1997 142th. |
|
Greber Urs F |
Viruses as parasites and gene
transfer vehicles into cells. |
3-12. (1) |
|
Viruses emerge randomly
but frequently among the human population. Successful viruses are able
to infect a large number of individuals. These viruses have learnt to exploit
cellular mechanisms to enter their host cells and escape the host's immune
surveillance. Type C adenovirus, a human cold virus, aims at delivering
its DNA genome into the nucleus of epithelial cells in the respiratory
tract. It enters target cells by receptor-mediated endocytosis, penetrates
the endosomal membrane and is transported to the cell nucleus. It attaches
to nuclear pore complexes and then disassembles and releases its genome
into the nucleus. What are the molecular mechanisms which control this
finely tuned entry and disassembly program? |
Bandtlow Christine
E |
How nerve fibers find their targets. |
13-21. (1) |
Neuronal growth cones
traverse long distances along appropriate pathways to find their correct
targets. Secreted and cell surface molecules in the growth cone's surface,
trigger second messenger signals, and lead to appropriate steering decisions.
Growth cones appear to be guided by at least four different mechanisms:
contact-mediated attraction, chemoattraction, contact-mediated inhibition,
and chemorepulsion. These mechanisms are mediated by different families
of guidance molecules, including neural cell adhesion molecules of the
immunoglobulin superfamily, netrins, and membrane bound inhibitors such
as RAGS, all of which appear to be highly specific in their activity on
certain growth cones. We are just beginning to gain insights into the function
of these and other molecules in the developing and regenerating nervous
system. |
Mensch Roland, Känel
Barbara, Uehlinger Urs |
Short-term effects of weed removal
on a stream of the Swiss plateau. |
23-31. (1) |
In May and June 1995,
we studied the short-term effects of macrophyte removal in a nutrient rich
stream on macroinvertebrates and ecosystem metabolism. Following removal
of macrophytes, water depth decreased by more than 50% and flow velocity
doubled. Macroinvertebrate density was reduced by 65% after macrophyte
removal. Chironomids and Simuliids were most affected because macrophytes
are important habitats for these taxa. Asellus and Gammarus decreased after
the removal of the plants presumable due to changed hydraulic conditions.
Primary production was reduced by more than 50% after the removal of macrophytes.
Community respiration, as well as respiration at the sediment surface,
were little affected. Macroinvertebrates and macrophytes showed no recovery
within 4 weeks after the disturbance, whereas primary production recovered
within 4 weeks. |
Gassmann Fritz |
Complex systems: The combination
of chaos and order. |
41-48. (2) |
|
During the last two
decades, new perceptions grew within the exact natural sciences relativating
basic notions such as determinism and predictability of macroscopic phenomena.
The result was a surprising opening towards life phenomena giving much
hope for the possibility of a physical understanding of biology. The basic
notions of chaos and self-organization are introduced from a historical
point of view and then illustrated with a water wheel as a model system.
On the basis of this system, we report also a new discovery concerning
noise-induced chaos-order transitions. Finally, some questions are raised
towards the calculability of natural systems and the possible physical
understanding of life. |
Simon Hans Uwe |
The physiological and pathophysiological
impact of programmed cell death. |
49-53. (2) |
|
During the past few
years, some progress has been made in understanding the control and mechanisms
of programmed cell death (PCD). Nevertheless, major aspects remain undefined.
However due to the availability of several important genes which play a
role in the regulation of apoptosis, it should be possible to identify
further proteins involved in this process. In addition to defining the
molecular mechanisms of PCD, one should define the survival factors and
the receptors for these factors for every cell type. Besides basic research,
it is important to study the role and regulation of PCD in disease. Such
clinical research will not only lead to more pathophysiological insights
into diseases, but may also facilitate the design of new drugs to normalize
dysregulated PCD. This review gives an introduction into our current understanding
of both the physiological and pathophysiological role of PCD in humans. |
Leu Urs B |
History of dinosaur-research. |
55-67. (2) |
|
There follows a description
of the history of the reconstruction of the dinosaurs with reference to
some rare documents preserved in the Paleontological Museum and the Central
Library in Zurich. The history of Swiss research is also discussed as well
as the first report of Swiss dinosaurs which has been published in 1824.
Because the ichthyosaurs and pterosaurs are often commonly associated with
the dinosaurs, they are also subjects of this paper. |
Brinkmann Winand |
Ichthyosaurs (Reptilia) from the
Middle Triassic of Monte San Giorgio (Ticino, Switzerland) and Besano (Lombardy,
Italy): The present state of research. |
69-78. (2) |
|
Middle Triassic marine
sedimentary layers (Grenzbitumenzone, Lower Meride Limestone, Kalkschieferzone)
from the Ticino calcareous Alps at the Swiss-Italien border have long been
recognized by specialists as a classical fossiliferous area (Monte San
Giorgio/Besano), rich in exquisitely preserved fishes and especially many
different kinds of marine reptiles, among them ichthyosaurs. Palaeontologists
of the University of Zurich have been studying the abundant ichthyosaur
material from that region in detail for some years. The aim of the paper
is to give an overview of the present state of the research. The Ichthyosaurian
fauna of the "Grenzbitumenzone" or Besano Formation of the Ticino calcareous
Alps is very diverse. The fauna consists of individuals of the small mixosaurs
Mixosaurus, which are very frequent, and Phalarodon, one specimen, as well
as some larger shastasaurids, for example Besanosaurus and Cymbospondylus.
The mixosaur material, including some remains of embryos of Mixosaurus,
and an additional shastasaurid from Monte San Giorgio are currently being
studied Here, for the first time, the occurrence of the genus Phalarodon
in Southern Ticino and the respective conclusions are reported. |
Hantke, René Adrian E.
Scheidegger |
Zur Morphogenese der Zürichseetalung |
89-95, (3) |
|
|
|
McKenzie Judith A,
Andres Miriam S, Vasconcelos Crisogono |
How do bacteria make rocks? |
97-104.(3) |
An earth-system-science
approach to the study of chemically produced sedimentary rocks is multidisciplinary,
involving an integration of biology, chemistry and physics. With this approach,
the study of rocks on a geological time scale is linked to processes observed
in modern natural environments, which in turn provide material and models
that can be tested in the laboratory. Studies of ancient rocks demonstrate
that the interaction of bacteria with their environment has resulted in
the precipitation of chemical sediments throughout geologic time, beginning
with the oldest known sedimentary rocks from 3.5 Ga, whereas studies of
modem environments provide information on the conditions prevailing in
the geologic past. Dolomite precipitation is presented as an example of
a chemical sediment that illustrates the influence of geomicrobial activity
on the production of the rock dolomite throughout geologic time. |
Lippuner Mario |
Agile frog (Rana dalmatina Bonaparte,
1840) new for the cantons of Zurich and Thurgau. |
105-113. (3) |
|
Rana dalmatina is
described as a faunal element of the cantons of Zurich and Thurgau. In
the mchlt Red List mchgt of Switzerland the species is listed as mchlt
endangered mchgt north of the Alps. It has been known to occur in the canton
Of Schaffhausen and in Southern Germany north of the River Rhine which
has been regarded as the southern boundary of range. The fact that R. dalmatina-specific
habitats exist south of the River Rhine in the neighbouring parts of the
cantons of Zurich and Thurgau led the author to explore some wet-sites
in this area in April 1996. He found R. dalmatina in two places: one in
the community of Unterschlatt, canton of Thurgau, and one in the community
of Trullikon, canton of Zurich. In spring 1997 further findings followed
in 13 objects. In' the present report the records and the corresponding
habitats are described. Comparison of the habitats with bibliographical
references led to recommendations for the protection of R. dalmatina. Measuring
the adults, of two different populations showed that males have an average
head-trunk-length (AHTL) of 51.5 mm and 49.1 mm respectively and an average
weight (AW) of 16.4 g and 15.7 g respectively. The corresponding values
of the females were: AHTL = 62.8 mm and 62.1 mm respectively; AW = 34.2
g and 31.7 g respectively. Furthermore a morphological character distinguishing
the larvae of R. dalmatina from R. temporaria is presented. |
Braegger Christian P |
Is there a need for basic research
in clinical medicine? New immunosuppressive treatment strategies in Crohn's
disease. |
115-122. (3) |
|
Crohn's disease is
a chronic inflammatory bowel disease of unknown etiology. During the last
20 years there has been a steady rise in the incidence and prevalence of
the disease in Europe and the United States. The rise in the incidence
is even greater in children. In more than 30% of the patients the disease
begins during childhood. Treatment of Crohn's disease is often not effective
enough and associated with many side effects. However recent findings in
immunology and molecular biology provided new insights into the pathogenesis
of the disease. New experimental approaches of immunosuppressive treatment
are currently developed. |
Martin A. Suhm |
Aus dem Gesellschaftsleben eines
kleinen Moleküls:Eine Einführung in die Molekularsoziologie |
133-143, (4) |
Jovan Pavlovic |
Abwehrstrategien gegen Grippeviren
Induktion antiviraler Mx-Proteine durch Interferon |
145-152, (4) |
Urs Boutellier |
Auch die Atmung limitiert die
körperliche Leistung bei gesunden Personen |
153-159, (4) |
Nazario Pavoni |
Geologische Exkursion an die Lägern
vor 160 Jahren |
161-168, (4) |
Nazario Pavoni |
Diskussionsbeitrag zum Forum-Artikel
"Zur Morphogenese des Zürichseetalung" von R.Hantke & A.E. Scheidegger |
169-172, (4) |
1996 141th. |
|
|
Ruth Dreifuss |
Ethik und Verantwortung in der
Wissenschaft |
3-7, (1) |
J. Osterwalder |
Atomare Struktur auf Katalysatoroberflächen |
9-15, (1) |
Opravil Milos |
How do microorganisms profit from
immune deficiency? |
17-28. (1) |
|
In the course of evolution,
microorganisms found different ways to escape the immune defence. One of
the viral strategies is the introduction of their genetic information into
chronically infected human cells, as shown for the herpes viruses and HIV
Some bacteria or parasites can persist in the macrophages or in a cyst
during the whole life without causing any symptoms. Frequent mutations
and antigenic shift can additionally impair the recognition by the immune
system. The cells of the immune system itself may also become infected
which will directly or indirectly damage the immune defence. Immune deficiency
will facilitate the establishment of an infection, even by microorganisms
that are usually not pathogenic. Additionally, reactivations of latent
infections occur frequently and lead to serious and chronic diseases. Without
the adequate functioning of the immune system, antibiotic treatment alone
will not be able to eliminate the microbes. Moreover, better conditions
for the growth of microorganisms will promote the development of resistance
with further impairment of the treatment effect. |
Hilbrecht Heinz, Graf
Pinthus Brigitte |
3-D morphometry of palates with
simple image analysis. |
29-33. (1) |
A variety of methods
exists for the medical treatment of cleft lips and palates, with a common
goal to establish a normal geometry of the palate. Using x-ray absorption
we transformed the three-dimensional height variation in gypsum casts of
palates to a two-dimensional image, computed thicknesses of gypsum through
correlation of gray values in the image with measured thicknesses, and
measured the height variation along three lines across the palate with
an image analysis system. One criterium to choose methods for image generation,
image analysis, data evaluation, and presentation was to involve medical
doctors without specialised experience in image analysis and morphometric
data handling, who should be able to evaluate and to apply results based
on their medical experience with the patients. Both analysed methods for
the medical treatment of cleft lips and palates produce comparable results.
One method, however, achieves its goal to cure the patients after significantly
shorter time. |
Nadal David |
Epstein-Barr virus in tumor cells:
Stowaway or helmsman? |
45-52. (2) |
|
The specifically human
Epstein-Barr virus (EBV), a member of the herpes virus family, has been
discovered more than 20 years ago and can be found in certain tumors. This
justifies the question whether it acts as causative agent. The primary
infection is usually acquired in early life and may result in infectious
mononucleosis. Despite targeted immune response the virus cannot be cleared
from the organism. Approximately 95% of the adult human population harbours
the EBV The main targets are the B lymphocytes in which the virus exhibits
either lytic (productive) or latent infection. The latter confers to B
lymphocytes increased potency to proliferate. In immunologically healthy
individuals, the incited proliferation is confined by cytotoxic T lymphocytes.
However the EBV may escape the attack by reduced expression or mutation
of latency genes. The expressed gene patterns suggest that in tumors of
immunocompetent individuals the EBV behaves as a stowaway or as a camouflaged
saboteur. By contrast, there is no doubt that in tumors of immunocompromised
persons the EBV acts as a helmsman. |
Schuepp Hannes, Frey
Beat |
The complex and dynamic interactions
between the arbuscular mycorrhizal fungi and the plants. |
53-63. (2) |
Arbuscular mycorrhizas
are an universal, mutually beneficial, symbiosis between plants and fungi.
They are most common in almost all plant species in natural and agroecosystems.
They form abundant internal structures within the roots and extensive external
mycelia throughout the soil. Arbuscular mycorrhizal fungi act as a major
interface between the plants and the biotic and abiotic components of the
soil. The complex positive interactions of the symbiosis concerning nutrition
and development of plants as well as the improving soil structure and enhancement
of bioactivity has become only in recent years a topic of comprehensive,
interdisciplinary research. Some results are presented concerning the dynamics
of the biomass of the mycorrhizal fungi and their role in the nitrogen
cycle mainly with regard to transport and availability of nitrogen. |
Vogel Ralph Bernd,
Egger Heinz, Schweingruber Fritz Hans |
Interpretation of extreme tree
ring values in Switzerland based on records of climate between 1525 and
1800 A.D. |
65-76. (2) |
After the astronomer
Andrew Ellicot Douglass succeded in dating the famous cliff-dwellings of
Pueblo Bonito by means of wood remains, historians and archaeologists throughout
the world began increasingly to include dating by tree rings in their research.
In Europe the felling dates of thousands of trees were set in their historic
context. Nevertheless, climatological interpretation was largely unsuccessful
as the tree rings in wood remains from former settlements contained little
information. However where extremely broad or narrow rings were observable
it became possible to determine a relationship to extreme climatic events.
By mapping of what are termed pointer values and intervals of climatically
uniform Mittelland, it has proved possible, with the aid of climatic records,
to recognise and explain years with extreme events, for instance years
with very cold winters (e.g. 1624) and dry or wet summers (e.g. 1636 or
1673). In some years the dendrochronological data do not match the climatic
records. Consequently it may be possible in future to supplement the data
from climatic records with dendrochronological information. |
Bucher Fritz |
Rhinoceros protection: An example
from Kenya. |
77-80. (2) |
|
The survival of all
rhinoceros species is endangered on a global scale, because the area of
their habitats decreases and because they are killed for their horns. Even
the formerly quite numerous African black rhinoceros with populations estimated
in 1968 to still number 11 000 to 13 500 individuals has meanwhile been
drastically reduced to about 2500 individuals. In many African countries
it is by now extinct or close to extinction. Only in South Africa, Namibia,
and Kenya the populations are stable or even increasing. Similar or worse
reports concern the other rhinoceros species in, Africa aid Asia respectively.
After a short historical survey on the rhinoceros slaughter in the 19th
century the author analyzes the present situation and comes to the conclusion
that the rhinoceros species have only a chance of survival when guarded
in well watched surveyable and fence-protected sanctuaries. Important is
that the native human population is included into the protection programme
and profits from it. - As a specific example the Ngare Sergoi Rhino Sanctua
in Lewa Downs (Kenya) is described in more detail. |
Minder Elisabeth I,
Schneider Yin X, Schäfer B, Rüfenacht U |
Porphyrias in changing times:
From biochemistry to gene therapy. |
93-101. (3) |
Porphyrias are a group
of inherited disorders of porphyrin metabolism. The main symptoms of porphyrias
can be either repeated attacks of abdominal pain and psychotic symptoms,
or a hypersensitivity to the sunlight Well-known dignitaries, who might
have suffered from porphyrias, were Vincent van Gogh and King George III
of England. The diagnosis of porphyrias can be established by increased
levels of porphyrines in various body fluids. Defects in the enzymes of
the heme-biosynthetic pathway are the causes of porphyrias. Many of these
defects have been identified in the respective genes. In vitro substitution
of the normal gene sequence by a defect one allows the study of the effect
of this particular defect on the enzyme activity and the correlation with
clinical expression. Since there is no effective therapy for most of the
porphyrias, people focus their attention on the gene therapy research,
ie. replacing the defect genes by normal ones that might bring a correction
of the disorders and in turn cure the patients. Successful in vitro gene
therapy experiments have shown promising results in two forms of porphyrias.
However, there are still some obstacles to be overcome before applying
gene therapy to patients. |
Scheib Stefan |
The Gamma Knife: Medical physics
meets neurosurgery. |
103-111. (3) |
|
The first and to date
only Gamma Knife in Switzerland was installed at the "Klinik Im Park" in
Zurich in September 1994. This treatment facility is designed to perform
stereotactic radiosurgery of small intracranial tumours (both malignant
and benign) and arterio-venous malformations. Stereotactic radiosurgery
is a technique in which a single high dose of radiation is applied with
an extremely high degree of spatial accuracy. The method can be used instead
of or in addition to neurosurgery. The Gamma Knife uses 201 converging
beams of 60cobalt radiation and this "crossfiring" technique gives a small
sphere of high dose at the target lesion with sparing of the surrounding
normal brain tissue. By positioning one or more such dose spots within
the target lesion virtually any required 3-dimensional dose distribution
can be produced, in order to cover the target volume with the required
dose. To date over 42 000 patients have been treated with this technique
at over 70 centers world wide. The complete treatment procedure last between
about 3 and 8 hours and can be carried out either on an outpatient basis,
or with a short stay in hospital. |
Spichiger Keller Ursula
E |
How far do chemical sensors resemble
sensillae? |
113-122. (3) |
The structure of biological
sense organs such as the antennulae of crabs or even simple taste or olfactory
hair-sensillae of insects is complex and their supply with nutrients as
well as their response functions are complex, too. The goal of developing
chemical sensors is, however, to design sound, simple and efficacy tools
to use in analytical chemistry. Chemical sensors in a strict sense are
designed and realized based on synthetic host molecules. The environment
of the host-guest interaction contributes significantly to the selectivity
of this tool. Components of biological sense organs e.g. enzymes or other
receptor molecules are used in chemical sensors in order to have access
to the natural discrimination of interfering substances. Such sensors are
specified as Biosensors. Common to all chemical sensors is their reversible
or rapidly regenerable response to varying concentrations of "stimulating"
molecules or target analytes. This feature allows to operate those sensors
in continuous monitoring. The various types of chemical sensors can be
described schematically by a common model involving, firstly, the section
of molecular recognition; secondly, the transducing section where the molecular
recognition process is translated into a physical quantity, and thirdly,
a secretion responsible for signal processing and yield of information. |
Urmi Edwin, Schnyder
Norbert |
A digital system of physiographic
surface units in Switzerland and in Liechtenstein. |
123-131. (3) |
The authors propose
a digitalized system of physiographic units allowing to produce automatically
bryophyte distribution maps. The units were generated to be comparable
in size and to be as homogeneous as possible regarding geology and climate.
The system was designed for ARC/INFO but it can be applied together with
other geographical information systems. It consists of 413 physiographic
units of Switzerland with an average surface of exactly 100 km-2 and of
2 smaller units of Liechtenstein. It proved useful for the purpose for
which it was originally assigned with or without modifications, it is expected
to facilitate the processing and the presentation of other geographical
data, too. |
Klaus Ensslin |
Klassisches Chaos und Quantentransport:
Experimente an Halbleiter-Nanostrukturen |
146-152. (4) |
Keller Beat |
Traditional and molecular use
of the biodiversity of wild grasses for wheat breeding. |
153-160. (4) |
|
The improvement of
disease resistance is one of the most important goals in wheat breeding.
Many of the desired resistances against fungal and viral pathogens are
not present in the wheat gene pool. However, such genes are often found
in wild grasses which are related to wheat. It is possible to transfer
resistance genes from a number of wild grasses into wheat by sexual crosses
and cytogenetic methods. In these introgressions, large chromosomal fragments
are transferred from the wild grasses into wheat. Besides the desired resistance
gene, there is a large number of additional genes on these fragments which
often result in undesired traits in modern wheat varieties. Therefore,
only a small number of the useful traits present in the gene pool of wild
grasses has been introduced into commercial wheat varieties. To use the
genetic diversity of resistance genes of wild grasses to a larger extent
in wheat breeding, the genes will have to be isolated with molecular methods
to allow the separation from other genes of the wild grass. The progress
in the characterisation of resistance genes in small grain cereals is briefly
described for rice and wheat. In the next years, we can expect the isolation
of a larger number of resistance genes from wheat and its related grasses. |
Schlumpf Margret,
Lichtensteiger Walter |
Environmental endocrine disruptors:
Their role in loss of animal species. |
161-171. (4) |
The impressive loss
of animal species in the 20th century is caused mainly by human activity.
Of great concern is the yet unexplained accelerated decrease of animal
species during the last 3 to 5 decades. Habitat degradation and chemical
pollution are among the primary determinants contributing to this process.
Numerous examples from plancton to humans document the relationship between
chemical burden (organic chemicals and heavy metals) and impaired reproduction
and development. However, at present it is not possible to assess the significance
of a prolonged exposure to environmental chemicals, in particular because
of insufficient information on toxic effects in the low dose range with
long-lasting exposure (one generation or longer). Reproduction and ontogeny
are highly sensitive to chemical insults, especially by chemicals known
as endocrine disruptors, interacting with the regulation of physiological
functions by hormones. In adults such interactions may interfere directly
with reproduction; during critical phases of development they may lead
to persistent changes in structure, biochemistry, and function of various
organs including the reproductive organs. At the present time, we are faced
with a discrepancy between the paucity of data on reproductive and developmental
toxicology of environmental chemicals and the enormous number of bioaccumulating
xenobiotics. |
Jeanmonod Daniel,
Magnin Michel, Morel Anne |
Common thalamic physiopathology
for sensory, motor, and limbic positive symptoms in man. |
173-181. (4) |
Positive symptoms
arise after lesions of the nervous system. They include neurogenic pain,
tinnitus, abnormal movements, epilepsy and certain neuropsychiatric disorders.
Stereotactic medial thalamotomies were performed on 104 patients with chronic,
therapy resistant positive symptoms. Peroperative recordings of 2012 single
units revealed an overwhelming unresponsiveness (915%) to sensory stimuli
or motor activation. Among these unresponsive cells, 45% presented a bursting
activity with a rhythm between 3 and 5 Hz. These bursts fulfilled the criteria
for "low threshold calcium spike (LTS) bursts", which are strictly related
to thalamic cell inhibition. These bursts were identical for all positive
symptoms. Operations in the medial thalamus and in the pallidum allow a
reduction or relief of the positive symptoms. On the basis of these electrophysiological
and clinical results, we propose a unified concept for all positive symptoms,
centered on a self perpetuating thalamic cell membrane hyperpolarization,
similar to the one seen in slow wave sleep. |
1995 140th. |
|
|
Akeret Beat, Stössel
Fred |
Comparative ecological investigations
in nine ponds north of Zurich (Switzerland). |
3-17. (1) |
We measured temperature,
conductivity and several chemical parameters in 9 ponds. We also investigated
animal and plant diversity. The ponds ranged from regularly and thoroughly
mixed to stratified. Concentrations of nutrients spanned a wide range.
All ponds were at least partially anoxic, especially in summer - and even
near the surface oxygen concentrations were low. Nevertheless, biodiversity
was high in 7 of the 9 ponds. Overall, 192 taxa were found but only 1 species
occurred in all ponds. 9% (18) were found in more than four ponds, 20%
in two and 65% (124) only in one pond. Our study shows that each pond is
unique and is therefore hardly comparable to other ponds. |
Weibel Robert |
Spatial data handling and digital
terrain modelling. |
19-29. (1) |
|
Digital terrain modelling
allows to numerically model topographic relief and to simulate relief dependent
processes. Here, we use digital terrain modelling as an example to illustrate
the application opportunities and the potential of spatial data handling,
an essential component of modern geographical research. Three central objectives
of spatial data handling - information extraction, quantitative modelling
of spatial processes, and visualization of complex spatial relations -
are illustrated by application examples of terrain modelling. The corresponding
methods are briefly described. |
Hanggi Gaby, Felder
Peter |
Lasers in medicine. |
31-34. (1) |
In the past few years,
the continuous development of laser technology has led to remarkable progress
in medical therapy and diagnostics. Lasers are used in surgery as localized
heat sources to achieve tissue removal and coagulation of surrounding blood
vessels. Photodynamic therapy is a tumor treatment modality in which laser
light is applied to activate suitable photosensitisers. Shock waves generated
by means of pulsed high power lasers are used for the destruction of various
types of intracorporeal stones. |
Krause Martin |
Infectious diseases on the way:
Molecular aspects of pathogenesis. |
35-41. (1) |
|
First brief account
on the history of infectious disease and the successful therapy by means
of prevention and antibiotics is given. The growing problems caused by
developing microbial resistance to antibiotics and the appearance of new
infectious diseases as well as the reappearance of "old" infections require
further intensive research. Over a long time the study of the pathogens
was neglected in favor of the research on the immune system of the host
and its signal substances. Today it is accepted that during infection the
microbe is at least as important as the host and its defense lines. The
terms "pathogenicity" and "virulence of the infecting agent" are discussed.
Special attention is drawn to the pathogenesis of Vibrio cholerae (cholera
toxin) with its disastrous effects, to salmonellae and the regulation of
their virulence genes, and of Yersinia pestis with is adaptive mechanisms
in response to the changing temperatures in the rat, in the rat-flea, and
in humans. |
Burg Jean Pierre |
How many years can mountains exist
before they disappear in the sea? |
51-60. (2) |
|
The natural deformation
of rocks tells the rheological response of crustal material to forces due
to large movements between lithospheric plates. Geological structures also
tell about the slow collapse of mountain ranges due to the applied on thick
and hot, softened crusts. The subsequent vertical movements and topographic
changes may force changes in the wind circulation and, therefore, in the
global climate. In the lecture the unexpected relationship between internal
and external geodynamic systems is developed and some records in the geological
and climatic history of the Earth nearly 300 My ago are traced. |
Hatt Jean Michel |
Falcon and Cheetah: Man's hunting
companions. |
61-68. (2) |
|
For centuries man
has used certain animals and birds to hunt prey where technical means of
hunting were lacking. Countless sources testify to the intensive relationship
which built up between man and beast beyond the initial need. In this article
the history of hunting with the aid of cheetahs and falcons will be studied.
Both traditions have been deeply influenced by the development of modern
arms. The decrease in the cheetah population has led to the disappearance
of this method of hunting. Falconry, however, fortunately has a good chance
of survival in Europe due to great efforts of falconers in the protection
of birds of prey and their environment. |
Schmid Werner |
Genetic mosaicism in man. |
69-74. (2) |
|
Various kinds of genetic
mosaicism are not only scientifically interesting phenomena but are of
clinical relevance as well. This is particularly so for mutations occurring
in the early embryo, for the mutations leading to cancerous cells, and
for mosaicism in patients with chromosome aberrations. Random events in
conjunction with the inactivation of one or the other X chromosome in female
cells give rise to the occasional heterozygous woman who is clinically
manifest for hemophilia or muscular dystrophy. Mosaicism is widespread
among the newly discovered triplet repeat diseases, among them Huntington's
chorea and myotonic dystrophy. Their triplet expansions are unstable not
only meiotically but mitotically as well. Diseases caused by mutations
or deletions in the mitochondrial chromosome can be compatible with life
only in mosaic condition. |
Sengstag Christian |
Predisposition to colorectal cancer:
Familial inheritance of mutant DNA repair genes. |
75-82. (2) |
Recent research results
confirm the hereditary nature of certain forms of colorectal cancer Systematic
screening of individual members within cancer-prone families revealed four
novel genes which are present in an altered state in affected family members.
The newly identified genes hMSH2, hMLH1, hPMS1 and hPMS1 exhibit good similarity
to known bacterial genes and they were identified to code for proteins
which are involved in the recognition and repair of DNA mismatches. The
observed alterations in the genes lead to a defect in the removal of spontaneous
DNA damage, the consequence of which is the outbreak of cancer. This review
describes the scientific route that has led to the identification of these
four genes. |
Ryffel Bernhard |
Interleukin 12: Adjuvant in tumor
therapy? |
83-87. (2) |
|
Interleukin 12 (IL-12)
is produced in the body by macrophages and B-lymphocytes in response to
bacterial infections and intracellular parasites and establishes a link
between natural defense mechanisms and acquired immunity. IL-12 stimulates
the immune system, especially natural killer cells and cytotoxic T-lymphocytes,
which play an important role against infections and tumor cell growth.
The biological properties of IL-12 are briefly reviewed and the encouraging
results from experimental cancer studies are presented. The potential application
of IL-12 for cancer therapy in patients is discussed along with the expected
adverse effects of such a therapy. |
Hanggi Gabriella |
Contrast agents for diagnostic
imaging. |
97-104. (3) |
|
Over the past twenty
years the imaging techniques available for diagnostic use have experienced
a rapid and impressive development. Traditional radiology was revolutionized
with the advent of digital recording technology and associated computer
analysis. In addition to x-ray tomography, novel diagnostic imaging methods
based on entirely different physical principles, such as ultrasonography
and magnetic resonance imaging, have been introduced. By appropriate use
of these techniques detailed visualization of pathological alterations
in the human body can be achieved. However, this is not only due to progress
in instrumentation, but also to the development of suitable contrast agents.
For x-ray imaging, several well tolerated iodine-containing contrast agents
are now available, thus providing a wide application range. For contrast
enhancement in ultrasonography, a product based on microscopic air bubbles
has been developed which, however, is currently limited to the use in cardiology.
Paramagnetic gadolinium complexes are well established in magnetic resonance
imaging for a sensitive detection of tumors and metastases in the brain
and in soft tissue. Superparamagnetic magnetite particles show selective
accumulation in healthy liver tissue and thereby permit an earlier and
more reliable diagnosis of liver tumors. |
Hansjörg Seiler |
Umweltrisiken als Gegenstand interdisziplinärer
Risikoforschung |
105-112 (3) |
Wilfried Haeberli |
Permafrost und Blockgletscher
in den Alpen |
113-121 (3) |
Gmur Rudolf |
Aggressive opportunistic bacteria
and a deregulated immune response: Triggers of periodontitis. |
123-131. (3) |
|
Periodontitis is caused
by a destructive inflammation of the tissues which, as a functional unit,
anchor the teeth. Prerequisite for the disease is the colonization of the
teeth and in particular the gingival crevice with aggressive opportunistic
bacteria. Certain substances from the bacterial flora are directly toxic
to host cells, others are capable to strongly stimulate the local immune
response which may result in immunopathological tissue destruction. In
general, periodontal bacteria alone seem not to be able to cause periodontitis
as long as polymorphonuclear granulocytes are present and functional. If
the bacteria succeed in outflanking or eliminating the phagocytes (rarely
the case) severe periodontitis is an immediate consequence. Much more often,
a basically sound by chronically overstimulated local immune defense is
associated with periodontitis. In such cases, a critical change in the
cytokine profile, presumably caused by external or other destabilizing
factors (smoking, drugs, age, diabetes, stress, etc.), may be essential
in triggering a burst of periodontitis. |
Pellegrini Antonio |
Lysozyme: An old protein keeps
the interest of research constantly awake. |
133-140. (3) |
|
Since its discovery
by Alexander Fleming 70 years ago, lysozyme has attracted the attention
of a large number of biological and medical scientists. Because of the
greater antibacterial activity of penicillin, lysozyme was neglected for
30 years. However, starting in 1960 a revival took place; lysozyme became
the first enzyme whose molecular structure was completely analyzed. Recently
it has been shown that the bactericidal activity of lysozyme is independent
of its enzymatic activity. The finding that a pentadecapeptide derived
from the enzymatic digestion of lysozyme shows antibacterial and antiviral
activity is new. |
Arnold O. Benz |
Koronen: Heisse Hüllen kühler
Sterne |
149-153 (4) |
Billeter Martin |
Water molecules within and around
proteins. |
155-161. (4) |
|
Proteins participate
in almost all biological processes; they thus affect many properties of
living organisms. The multitude of protein functions is made possible by
an even larger multitude of three-dimensional protein structures. The function
of a protein depends on direct contacts to other molecules; therefore protein
functions are strongly correlated to protein surface structures. The study
of interactions of proteins with their environment requires the consideration
of neighboring water molecules. Different experimental techniques (X-ray
crystallography, NMR) show different aspects of protein-water interactions.
By combining these results a model emerges, in which water does not simply
fill the space between larger molecules but also enables fluctuating interaction
networks between proteins and other molecules with the resulting entropic
advantages. Complexes of proteins with DNA, where the proteins "read" the
genetic information of the DNA, illustrate this model. |
|
|
|
Leuthold Walter |
Changes of the vegetation in the
Tsavo National Park, Kenya, From 1970 to 1994. |
163-171. (4) |
|
Two series of photographs
taken at spatially fixed locations in 1970 and 1994 document the development
of woody vegetation under changing ecological conditions in Tsavo National
Park. Kenya, over nearly a quarter-century. The original vegetation was
altered considerably through the combined influences of elephants and fire
in the 1950s and 1960s. Meanwhile, the elephant population has decreased
substantially as a result of large-scale poaching for ivory during the
1980s. Presumably as a result, trees and shrubs have reappeared in large
numbers at the majority of locations sampled. The influence of fire in
impeding regeneration of woody vegetation has also been documented locally. |
Schmid Christoph |
Insulin-like growth factor: Hormone
and cytokine. |
173-180. (4) |
|
Insulin-like growth
factors (IGFs) were discovered by three independent groups interested in
biological activities exerted by serum: stimulation of proteoglycan synthesis
(sulfate incorporation) in cartilage by a growth hormone-dependent "sulfation
factor" (somatomedin), insulin-like activity (non-suppressible by anti-insulin
antibodies, NSILA) on adipose tissue and mitogenic activity on fibroblasts
in vitro (multiplication-stimulating activity). IGF I works as a somatomedin
in animals and in man. It is currently being tested in patients with diabetes
mellitus. Apart from its functioning as a blood-borne, liver-derived endocrine
hormone, it is produced in most tissues where it contributes to tissue
growth, repair, and remodeling (e.g. of bone) in a paracrine/autocrine
fashion. |
Rüetschi Bernhard |
Environmental pollutants and allergies. |
181-184. (4) |
With our present lifestyle,
we come into contact with an increasing number of substances which irritate
the skin and the mucous membranes, affecting the barrier function within
the respiratory passages and leading to increased susceptibility to infectious
diseases or allergens. Hence the number of allergic reactions world-wide
has increased over the past few years. New studies indicate that the interaction
of a number of factors is responsible for causing illness, in particular
for the increase of allergic reactions. For example, allergies are more
likely to arise in highly polluted areas. the coexistence and simultaneous
effect of environmental pollutants, allergens,a nd infectious agents can
cause latent allergies to develop. Smoking, active and passive, can also
contribute to the development of allergies. Multiplex interactions are
often encountered when tracing the cause of illness within a household.
There, one person can be completely healthy, while another is sensitive
to irritants, and yet another shows symptoms of an allergy. Most toxic
and allergic illnesses are polycausal and therefore difficult to understand
and explain. A diagnosis including detection of the damaging substances
or allergens and appropriate treatment is in many cases not possible. therefore,
preventive measures, especially the maximum possible elimination of noxious
substances, should have first priory. |
1994 139th. |
|
|
Jetzer, P. |
Gravitational lenses |
5-13, (1) |
|
Light rays are deflected
by masses, a fact,which is correctly described in the framework of the
Theory of General Relativity. If a mass is located approximately on the
line of sight of a more distant source, its light rays get focused on the
observer, due to the gravitational light deflection. Thus the mass acts
as a lens. One refers to it as gravitaional lens. We present the main historical
depelopments which lead to the recognition that light gets deflected by
masses, and to the discovery on the first gravitationla lens system in
1979. We discuss also the main applications of gravitational lenses in
astrophysics and cosmology, in particular for the dark matter detection. |
Bachofen, R. |
Biochemical cycles, microorganisms
and atmospheric trace gases. |
15-22. (1) |
|
The activity of a
variety of microorganisms in soil and water contributes to a natural increase
of the concentration of gases which influence the absorption of infrared
radiation in the atmosphere and therefore may change the climate on our
planet. Besides carbon dioxide (CO-2) methane (CH-4) and dinitrogenoxide
(N-2O) are of main importance. An increase in temperature will stimulate
microbial activity in most parts of the world and thus further increase
the production of these greenhouse gases. Certain algae and bacterial form
methylated reduced volatile sulfur compounds such as methanethiol, dimethylsulfide
(DMS), and dimethyldisulfide (DMDS). These gases are oxidized in the atmosphere
to sulfur dioxide acting as cloud nuclei. The microbial formation of reduced
sulfur gases may therefore reduce solar input and thus partially compensate
for the process of global warming. Microorganisms may also produce volatile
methylated compounds of other elements such as selenium, tellurium, arsenic,
lead, quicksilver, cadmium and tin. Many of these reduced organic metal
compounds are unstable and therefore might be involved in atmospheric chemistry. |
Lubini, Verena |
Biological investigations in the
Lower Reach of the Thur River (Canton of Zurich, Switzerland): I. Odonata,
Ephemeroptera, Plecoptera, Trichoptera and Megaloptera. |
23-31. (1) |
|
In the lower reach
of the Thur River aquatic insects were investigated in the years 1990/91
to calculate the effects of the lowering of the riverbed on the populations
and to control the recolonization. In this work only the faunistic results
are presented. During the investigation 3 species of odonata, 33 species
of Ephemeroptera, 21 species of Plecoptera, 43 species of Trichoptera and
one species of Megaloptera were recorded. 15 of the 33 species of Ephemeroptera
are rare. For two of then (Caenis rivulorum, Baetis buceratus) the Thur
is till now the only known locality in Switzerland. For the first time
larvae of Onychogomphus forcipatus (Odonata) are recorded in the Thur.
Sialis nigripes (Megaloptera) is recorded in Switzerland for the third
time. Therefore, the lower reach of the Thur is for the occurrence of several
species of national, in the case of Rhithrogena germanica (Ephemeroptera)
also of European importance. Abundance and biomass of insect larvae were
reduced only temporarily by two ten-year-floods, which occurred in February
1990 and in May 1991. |
Gasser Theo |
The statistical analysis of human
growth. |
33-41. (1) |
|
Traditional statistical
methods for analyzing longitudinal growth data rely on longitudinal models,
which proved to be inexact in applications. In this paper new statistical
approaches are presented which work without specifying a priori a model.
Their application to the analysis of skeletal growth and to the analysis
of parameters related to fat and weight led to new insight regarding human
growth. These developments will be illustrated by selected examples. |
Durrer Ruth |
Big Bang Cosmology: Answers and
problems. |
51-59. (2) |
|
Since it exists, humanity
has been interested in Cosmology, the question about the entire Universe.
In the 20th century, cosmology has evolved into a modern science which
today, due to new observing technologies, is in an especially active period.
In this contribution, I describe the most important cosmological findings
like isotropic Hubble expansion, primordial nucleosynthesis and the relic
microwave background radiation. They have led to a reasonably complete
picture of our Universe, leaving, however, a couple of open problems, some
which are mentioned at the end. |
Lang Walter |
Pathogenetic concepts of Alzheimer
dementia. |
61-70. (2) |
|
Alzheimer disease
is the most common form of dementia in old age. It is clinically characterized
by a progressive disturbance of higher brain functions such as language,
memory, visuo-spatial thinking, and cognition. Structural changes in the
brain include neurofibrillary tangles, senile plaques, congophilic angiopathy,
and neuropil threads. At present the etiology of the disease is unknown.
However, numerous pathogenetic concepts have been developed, which will
be discussed in this review. |
Erni Guido, Preisig
Hans Rudolf |
Biological investigations in the
lower reach of the Thur River (Canton of Zurich, Switzerland)-II. Algae. |
71-78. (2) |
Algal samples were
collected at nine different sampling stations in April, July and September
1990. In total, 123 algal taxa (118 species and 5 varieties) were found.
Diatoms dominated with 89 taxa (84 species); chlorophytes (26 species),
cyanophytes (6 species) and chrysophytes (one species) were also present.
The algal diversity is comparable to that of similar rivers, which have
been investigated in equal detail. Really rare species did not occur. Although
some of the diatoms have not been recorded frequently in the literature
so far, these are probably not rare, but have only been overlooked or misidentified
in previous studies. We used diatoms as biological indicators of water
quality. Our studies generally indicate moderately polluted conditions.
However, at least sometimes a critical state of pollution also occurred. |
Keller Peter, Hanselmann Kurt |
Evaluation of the success of lake
restoration treatments: Dynamics of mineralization in hypolimnetic water
layers close to the sediment (Lake Pfaeffikon, Canton of Zurich). |
79-92. (2) |
|
Lake Pfaffikon is
one of the highly eutrophic lakes in the pre-alpine region of Switzerland.
For the last few years, the oxygen supplied to the hypolimnion during springtime
circulation was consumed regularly during the stagnation period by microbial
degradation reactions. Internal restoration of lake Pfaffikon was started
in 1992. During the winter months when the lake is destratified, the water
is artificially circulated by injecting compressed air at the deepest location.
As part of the impact assessment we followed the rates of consumption of
oxygen, nitrate and nitrite as well as the production of ammonia and phosphate
during the summer of 1993. Our results indicate that - dissolved compounds
are distributed in the water layer closest to the sediment not only by
turbulent diffusion but also through horizontal water movements, - microbial
mineralization is not only active in the uppermost sediment layers but
also in the hypolimnetic water layers just above the sediment, - the biogenically
produced heat which is released into the hypolimnetic mineralization horizons
leads to measurable changes in the temperature profile near the sediment,
- by the additional enrichment of the hypolimnion with oxygen in winter
the oxic conditions near the - sediment can be maintained until the end
of May, - the elevated oxygen content in the hypolimnion is still insufficient
for aerobical degradation of the sedimenting biomass - and to maintain
oxic conditions at the sediment surface. |
Straumann Norbert |
Albert Einstein: On the way to
the theory of gravitation. |
103-112. (3) |
Einstein's early contributions
to a relativistic gravitation theory are discussed in the light of his
publications and his extensive correspondence, which has recently appeared
in volume five of the Collected Papers. We are trying to exhibit the course
of development of the theory until spring 1914. |
Kaiser Klaus Felix |
On the trail of the glacial climate
by tree-rings and snail shells. |
113-122. (3) |
The Alpine glaciation
reached its maximum extent around 20,000 to 18,000 years B.P. The Limmattal
Lobe of the Linth-Rhine Glacier, e.g., formed the stadials of Killwangen
and Schlieren. The climatic development that had started during this coldest
phase of the last ice age becomes more and more evident towards the end
of the Glacial. The Late-glacial began around 12,500 years B.P., when the
disintegration of the ice lobes had progressed. It forms the most interesting
phase of the last Glacial and is characterized by abrupt climatic improvements
interrupted by several shorter or longer reversals. The environmental conditions
calm down with tile beginning of the Holocene, when the actual interglacial
started. The following paper focuses on this transition between Full-glacial
and early Holocene and its variations evidenced by the features of mollusc
shells and annual rings of fossil trees (Abb. 1). |
Knoepfel T |
How nerve cells communicate. |
123-130. (3) |
|
The neurosciences
involve a wealth of data increasingly difficult to be integrated by the
single scientist but also covers more general principles which have to
be considered. This article on "how nerve cells communicate" is organized
as a journey through the fields of neurophysiology. We start by using simplistic
drawings to illustrate some general principles of interneuronal communication.
How nerve cells communicate in the cerebellum, a specific brain structure,
will then be described at a level of the neuronal network. The journey
will finally lead to receptors for the neurotransmitter glutamate, providing
examples for an outline at the structural level of molecules. |
Meier Sybille, Voser Peter |
Clear signs: The Lake of Zurich
is recovering (Changes of the submerged vegetation as a result of improved
water quality). |
131-139. (3) |
|
In summer 1993 we
studied the submerged vegetation in different places in the Lake of Zurich.
The comparison of our data with recordings from around 1900 and from the
early seventies showed encouraging results. The Lake of Zurich seems to
be recovering. The waterplants seem to react to the improved water quality.
The most important changes that we noticed are the following: The water
is generally clearer than it was a few years ago. The abundant vegetation
of Potamogeton pectinatus that used to predominate the submerged vegetation
has disappeared in many places. Large areas of Characeae (an indicator
of clean water) were found in several places. Najas marina, only rarely
observed before, is now growing in the Lake of Zurich in large areas of
up to one hectar. Some red-list species are spreading again. The efforts
of water-protection have been successful. However, we should do everything
to keep or even improve the water quality of the Lake of Zurich. |
Oesch Bruno |
Prions, Mad Cow Disease and Other
Prion Diseases: Molecular Concepts. |
149-154. (4) |
|
Spongiform encephalopathies
are neurodegenerative diseases such as Creutzfeldt-Jakob disease in humans,
scrapie in sheep or bovine spongiform encephalopathy in cattle. The infectious
particle has been characterized in molecular detail leading to the identification
of a host encoded protein (denominated prion protein) which in a modified
form is part of the infectious particle. Different concepts for the infectious
particle and the role of the prion protein in the normal and the infected
animal will be discussed in this review. |
Pircher Hanspeter |
How does the immune system distinguish
between self and foreign? |
155-163. (4) |
|
The generation of
an effective immune response involves lymphocytes which are able to react
against foreign invadors. In contrast, lymphocytes do normally not respond
against self structures This state of specific immunologic non-responsiveness
against self is called tolerance. Why does the immune system not respond
to self? The low frequency of lymphocytes, reactive to a particular antigen
and the lack of appropriate reagents to detect such cells in vivo hampers
the experimental analysis of immunologic tolerance. To circumvent these
problems, transgenic mice were generated which expressed on most T-lymphocytes
one type a particular receptor specific self antigen. These mice allowed
new approaches to investigate the mechanisms of T-lymphocyte tolerance
which is discussed in this review. |
Amann Anton |
The Gestalt Problem in Chemistry:
The Generation of Molecular Shape by the Environment. |
165-174. (4) |
|
Quantum systems have
a holistic structure which implies that they cannot be divided into parts.
In order to create subobjects of a system, the Einstein-Podolsky-Rosen
correlations between all the subentities, e.g., all the molecules in a
substance, must be suppressed in the perceptional process. It is not at
all clear how this happens in detail! One can think of a psychological
or a quantum-mechanical explanation. In the latter case, it would be necessary
to discuss the observer (or at least a measurement apparatus) quantum-mechanically.
I do not want to go as far as that. My only intention is to make plausible
that very similar aspects and problems are interesting for Gestalt perception
and quantum mechanics (not all of them will be discussed): Holistic aspects,
creation of objects, dressing procedures, influence of the "observer",
classical quantities and classical structures. It is possible, in particular,
to explain the main characteristic features of quantum mechanics using
phenomena of Gestalt perception (and hence without using the mathematical
formalism of quantum mechanics). Optical "illusions" and single molecules
will be used to illustrate that point. Incidentally, it will be argued
here that at least part of a molecule's shape can be generated "automatically"
by the environment. A molecular shape of this sort arises in addition to
Lamb shift-type energy corrections. |
1993 138th. |
|
|
Kissling, E. |
Seismic Tomography: Imaging the
Earth's Interior with Earthquake Waves |
1-20, (1) |
|
Seismic tomography
has evolved from a combination of mathematical solutions to the inverse
problem of medical tomography and classical methods of seismology into
the most powerful tool available at present to image the 3-dimensional
structure of the Earth's interior. Under ideal circumstances and when top
quality data are used we may presently resolve complex structures of the
size of a few kilometers with high confidence. Tomographic images of the
Earth's mantle reveal large-scale lateral variations of seismic velocities
that generally correlate well with continents and mid-ocean ridges and
may be interpreted as the result of large-scale convection in the mantle
as postulated by plate tectonics. Subduction zones are destructive plate
boundaries where two plates converge thus forcing one of the plates to
plunge into the mantle where it slowly disolves at great depth. In southern
Alaska the oceanic Pacific plate is subducted beneath the continental North
American plate and this process results in high seismic, volcanic, and
tectonic activity. High-resolution tomographic images of subduction zones
may contribute to a better understanding of the subduction processes. Local
earthquake seismic tomography has been successfully applied to study in
detail the 3-dimensional subsurface structure of volcanoes. As demonstrated
by examples from Long Valley (California) and Yellowstone (Wyoming) the
method is particularly valuable when searching for magma chambers. |
Blum Hubert E |
Recombinant DNA technology: Principle
and medical applications. |
21-36. (1) |
|
Recombinant DNA technology
is of increasing significance for the diagnosis, therapy and prevention
of human diseases. The principle of recombinant DNA technology is demonstrated
and the medical applications are discussed. Apart from unanswered scientific
and medical questions, legal and ethical issues have to be solved. |
Woelfli Willy |
Accelerator mass spectrometry
and environmental research. |
37-66. (1) |
|
Accelerator Mass Spectrometry
(AMS) is a new ultra-sensitive single atom counting method, allowing to
determine the concentrations of the most relevant long-lived cosmogenic
radionuclides. These isotopes are deposited chronologically in the archives
of our earth, such as trees, polar ice, lake and deep sea sediments. By
measuring their concentration profiles, which in most cases is possible
with AMS only, information on past changes in solar activity, geomagnetic
field and earth climate can be obtained over long time intervals. After
a brief description of the method, three examples of application will be
given to demonstrate how this complex profiles can be deciphered and what
consequences this information for modern environmental science have. |
Wehrli Bernhard |
Chemistry at the sediment surface
in lakes. |
69-79. (2) |
|
Biogeochemical cycles
in lakes are strongly influence by thin biofilms at the sediment-water
interface. Rapid transformation reactions at this boundary determine the
fate of chemical species: Dissolved components diffuse back into the lake,
solid fractions are burried with the sediments and remain isolated from
the biosphere for geological time scales. High resolution in-situ sampling
with dialysis samplers and direct measurements of diffusive fluxes with
sediment landers yield quantitative estimates of the dominant processes
at the sediment water interface. The application of such methods is illustrated
with results from a study in Lake Sempach, an eutrophic Lake in central
Switzerland. This lake is artificially oxygenated in order to keep oxygen
concentrations in the deep waters above a limit of 4 mg O-2/l. However,
this technology cannot prevent that the sediment surface turns anoxic in
summer. As a consequence manganese and iron oxides dissolve and the adsorption
capacity of the sediments for phosphorus remains low. A decrease in external
phosphorus loading from agriculture is necessary in order to diminish the
sedimentation rates of organic carbon and to restore the phosphorus binding
capacity of the sediments. |
Oertli J Jakob |
Problems of analysing the environment. |
81-104. (2) |
|
A useful analysis
of the environment must be capable of predicting events in the system.
Energy and matter are exchanged between environment and object, and an
analysis of the environment should predict the type, velocity and extent
of these interactions. Taking soil analyses as an example, it has been
shown that the above-mentioned conditions are rarely if ever met. The reason
for this is that the experimenter is usually satisfied with having obtained
a particular analytical value of uncertain relevance; local soil conditions
are taken into consideration only insufficiently or not at all. A remedy
may be the mapping and measuring of stable soil properties which determine
soil reactivity (e.g. towards potassium or phosphorus). Once this reactivity
is known, it is sufficient to make simple analyses periodically so as to
establish the actual state of the system in order to make accurate predictions
and choose the best management. Such procedures pave the way for adequate
agricultural production with minimal damage to the environment and form
the basis for establishing legislation whose aim is environmental protection. |
Schoop, Ralph W. |
Alptransit - The Railway Tunnels
through the Base of the Swiss Alps - Geologic Considerations |
105-119, (3) |
|
Planning and construction
of the two rail tunnels through the Swiss Alps will be strongly influenced
by the geologic prognosis and its effectiveness in predicting zones of
different rockfabric. This is especially important in the Gotthard, where
the former sedimentary cover has been strongly altered during the alpine
orogeny. An early treatment of these sheared shists and sucrose dolomites
will be necessary to avoid delays in the progression of the Fullbore Tunneling
Machines which will be used wherever possible.
Because of the length of the Gotthard tunnel, 50 km,
and an overburden of up to 2500 m it is planned to start construction from
both ends and from one or two intermediate shafts in order to optimize
time and costs. About half of the Lötschberg tunnel (total length
35 km) will be in the sediments of the Helvetic and Ultrahelvetic nappes.
The flat lying folded marls and shales are difficult to predict and require
numerous shallow boreholes. The drainage system in the karstified limestone
of the Doldenhorn nappe is largely unknown and may cause problems during
construction. Special attention has to be taken to avoid influencing the
groundwater system of the deeply incised valleys of the Kander and Gaster. |
Sticher Otto |
Ginkgo biloba: A modern phytomedicine. |
125-168. (3) |
|
Phytomedicines based
on extracts from the leaves of Ginkgo biloba are used in the Federal Republic
of Germany and in France a rather long time for the treatment of peripheral
vascular insufficiency and cerebrovascular insufficiency, and disturbances
of cerebral function. In Europe, commercially available preparations based
on the special extract EGb 761 have a turnover of about 500 million US
dollars. Meanwhile also in Switzerland various Ginkgo preparations are
on the market. In this review taxonomy, botany, chemistry, pharmacology
and clinical applications as well as quality control of Ginkgo biloba and
phytomedicines based on leaf extracts of this plant are described. Research
work of the own laboratory dealing with quality control is discussed in
detail. |
Oertli J J |
The ascent of sap in trees. |
169-190. (3) |
|
A large, vigorous
tree can in the course of a day raise 1000 liters of water from the soil
into the crown and transpire it into the atmosphere. This corresponds to
several ten thousand liters per hectare and day. The tallest trees known
today reach heights of 100 m. This raises the question how it is possible
that such large quantities of water are transported to these heights. There
is no evidence of a pressure pump mechanism and a suction pump is, according
to the teachings of physics, restricted to a maximum lift of ten meters.
Capillarity in conductive elements can raise water to a few meters at best.
Our current view is that, nevertheless, water is raised by some kind of
suction. As a consequence, the sap pressure must be negative, i.e. it is
under tension. However, under these conditions water vapor is more stable
and the liquid water should boil. Boiling, however, is hindered because
of a high activation energy required for the formation of a critical bubble
size. Nuclei that usually assist the formation of vapor bubbles are missing
in the flow system of plants. They can be introduced by air entry through
pores in the surrounding walls. The danger of an air seeding increases
with the pore size. Bubble formation causes an emboly of the conductive
element. It will be emptied of liquid water and becomes dysfunctional.
It can become functional again only under specific conditions that are
rare in a tall tree. Several mechanisms offer some protection against negative
turgor pressures and their consequences. Reinforcements of vessel walls
protect against collapse, long vessels of wide diameter reduce pressure
losses during flow, and thus the incidence of an emboly whereas small,
short vessels offer a better protection after an emboly has occurred, because
the damage is localized. Bordered pits of gymnosperms possess some kind
of valve that closes the pits after an emboly has occurred in a tracheid.
This way, embolism is kept from spreading to other conductive elements.
Perhaps embolism is a critical factor that limits the heights of trees. |
Kucera Ladislav J |
City trees. |
191-202. (3) |
Trees fulfil in settlement
areas along roadsides or in parks numerous tasks. At the same time, they
are exposed to some extremely negative growth and living conditions. These
conditions lead to an accelerated aging (expressed by low vitality) as
well as to numerous diseases, caused in many cases by wood-destroying fungi.
Non-vital or diseased trees constitute a high risk for their environment
by creating accidents through broken or overthrown branches and stems.
It is one of the most important tasks of urban tree care to recognize such
potential risks and to take the necessary steps to eliminate them. In this
present paper, methods and instruments for the investigation of the internal
tree condition are presented. Particular attention is paid to the Vitamat,
an instrument developed at the SFIT in Zurich. This instrument makes the
detection of hidden fungal decay in stems and branches possible in a quick
and quasi-nondestructive manner. |
Sauter Willi |
The entomological collections
at the Institute of Entomology of the Swiss Federal Institute of Technology. |
203-218. (3) |
|
The history of the
Institute of Entomology has been presented several times on the occasion
of jubilees with emphasis on teaching and research. As a complement the
museological aspect will be stressed here and above all events during my
time as a curator of the collections are reported. A commented list of
the collections that are preserved in our collections is given. |
Burckhardt, J.J. |
Rudolf Wolf (1816-1893) |
227-229 (4) |
Larcher, Verena |
The Diary of Rudolf Wolf 1835-1841 |
231-240 (4) |
|
Rudolf Wolf kept a
diary for the years 1835-1841 which is mainly devoted to his study trips
to Vienna, Berlin and Paris and his first two years in Berne. These notes
are a valuable source not only to Wolf's biography, but also to the cultural
history of the period. The following text aims to give an impression of
the diary. |
Balmer, H. |
Rudolf Wolf at Berne |
241-256 (4)
|
|
In his time as a college
teacher in the Swiss town of Berne since 1839, Wolf made his fundamental
discovery of the connection between sunspots and geomagnetism. But nearly
nobody heard about this. Wolf was known as a good teacher for geometry
and physics, and even more as a friend of gymnastics and an excellent guide
for summer wanderings with his pupils in the Alps. Since 1847, he was responsible
for the little observatory of the University. In the small Bernese scientific
Society, he spoke about many subjects, e.g. meteorology or earlier Swiss
mathematicians. Many of these communications have been printed in the Reports
which he founded in 1843 and edited till 1855, when he went back to Zurich.
He was also the keeper of the archives of the Swiss Society of Natural
Sciences. They are still preserved at Berne. Wolf was very active for them
and created an immense collection of original letters written by naturalists
between 1760 and 1870. |
Lutstorf, H. |
Rudolf Wolf's Years in Zurich,
1855-1893 |
257-266 (4)
|
|
Rudolf Wolf lived
and worked after 1855 until his decease 1893 in Zurich, holding a lectorate
at the University and a professorship at the Polytechnicum for astronomy.
Until 1861 he was also a teacher of mathematics at the Upper Gymnasium.
Being director of the astronomical observatory he initiated the erection
of the new Federal Observatory (1862-1864). As head librarian of the Polytechnicum
he created the present ETH-Bibliothek with its rich treasures of first
editions (15th to 19th centuries). At the same time Wolf acted as president
of the Geodetical and the Meteorological Commissions. |
Friedli, T.K. |
Rudolf Wolf as a Pioneer of Sunspot
Research |
267-281 (4)
|
|
Fascinated by the
sighting of a large sunspot-group, Rudolf Wolf began his continuous sunspot
observations at Berne Observatory in 1848. As an apt index to quantify
the apparent sunspot activity, he introduced sunspot relative numbers
by adding ten times the number of groups to the number of individual spots.
This index soon became an international standard and is still in use today.
In 1852 he discovered independently of A. Gautier and E. Sabine the correlation
between the periodicities of sunspot- and geomagnetic-activity. To support
this discovery, he made use of historical sunspot records and thus was
able to verify the sunspot periodicity back to the year 1610 and to determine
the average duration of the sunspot cycle to 11.11 years. After moving
to Zurich in 1855 he was appointed Professor of Astronomy at the newly
established Eidgenössische Technische Hochschule (ETH). Here he founded
the Swiss Federal Observatory in 1864 whose first Director he became; he
initiated the famous series of Zurich sunspot observations which was continued
by his successors A. Wolfer, W. Brunner and M. Waldmeier, and is still
continued today on Wolf's original telescope. |
Ineichen, R. |
«... and I will stand the
hazard of the die» |
283-298 (4)
|
|
The empirical estimations
of probabilities play an important role in the applications of probability
theory. In order to get such empirical estimations, the astronomer Rudolf
Wolf performed an impressive number of experiments involving dice, needles
and cards. - The present work starts with a description of the notion of
«statistical regularity». We then go to some of Wolf's dice
experiments and we describe his tentative theory of the «real dice».
We conclude with his results about the ancestor of Monte Carlo's method
in the context of Buffon's needle problem and the random matching of two
equivalent decks of cards («probleme de rencontre»). |
1992 137th. |
|
|
Bentor, Y. K. |
Geological Events in the Bible |
1-27(1)
|
|
The books of the bible
contain numerous, frequently very exact, descriptions of geological events.
Some of these are discussed here: earthquakes and their accompanying landslides
(the crossing of the River Jordan), seiches and tsunamis (the flood), flooding
(Sodom and Gomorrah), faulting, burning gas seepages (the Burning Bush)
and volcanism (Mount Sinai). These geological events appear in the biblical
text mainly for artistic reasons; they serve as a suitable background to
dramatize the biblical account; they create a supernatural atmosphere for
the main stories, but the time and place at which they occurred are of
no importance to the narrator and might be shifted freely. |
Embrechts, P. |
Randomness |
23-40 (1)
|
|
Randomness enters
human thinking and behaviour, and physical modelling at every possible
level. Starting from every day interest on lotteries, to for instance intricate
problems related to nuclear reactor safety, most human endavour is to some
extend governed by the laws of chance. In the present paper we give a more
detailed description of one particular experiment allowing us to travel
the often winding road from experiment to mathematical theory. Via a short
excursion through the history of probability theory we spend some more
time on stochastic modelling in insurance by discussing some of the key
questions asked in risk theory. Finally, some examples relating to lottery
problems should warn the reader that a superficial intuition on randomness
often leads to false conclusions. |
Primas H |
Reorientation in natural sciences |
41-62 (1) |
Huber M |
Fibonacci numbers |
65-76 (2) |
|
After a brief introduction
to the life and the work of the Italian mathematician Leonardo Fibonacci
(about 1170-1240) his famous rabbit problem and its solution are presented.
This solution consists of a recursively described sequence of numbers,
today called «Fibonacci numbers». The explicit formula for
the Fibonacci sequence is named after Binet; it contains the ratio t
of the golden section. Another interesting connection between the golden
section and the Fibonacci numbers was already described by Kepler in his
«Harmonices mundi». This background may help to explain the
important role that Fibonacci numbers play in the leaf and floret arrangement
of plants (phyllotaxis). For instance, they appear in the capitulum of
compositae; the florets of a sunflower head are arranged in two families
of spirals, and the numbers of these spirals are, with rare exceptions,
two consecutive Fibonacci numbers. |
Busch, G. |
Albert Mousson, 1805-1890, Erster
Professor für Experimentelle Physik in Zürich |
77-89 (2) |
Holenstein E. |
Philosophy, the (other) Sciences,
and Life |
91-105 (2) |
|
The special sciences,
according to a common view, successively emancipated themselves from philosophy
and became independent disciplines. However, medicine can also claim mothership
in the genealogy of sciences. Moreover, there can be seen today a counter-movement,
a kind of rephilosophization of the sciences. The reason thereof is the
theory-ladenness of all experience. The openness of the problems of foundation
has as its consequence that philosophy can no longer assume the role of
a normative and critical judge, but only a task of evaluation. Divergent
world views are compatible with one and the same science. It is possible
to interpret these views as continuations of pre-scientific conceptions. |
Cogoli Augusto |
Biology and biotechnology in space. |
109-122. (3) |
|
Although biological
experiments are carried out in Space since two decades, it is only after
the advent of the european laboratory Spacelab in 1983 that scientists
are able to carry out a systematic program of investigations. The focus
of this paper is on cell biology. The results available today clearly show
that cells from all steps of evolution change their behavior dramatically
in space. Microgravity and cosmic radiation as well may be responsible
for the effects. The objectives of space biology are basic research, biomedical
diagnostic and bioprocessing. With the advent of the permanent manned space
station Columbus at the end of this century a significant expansion of
the research in microgravity is expected. |
Balderer Werner |
Saltwater-Freshwater, a problem
of coastal areas only? |
123-142. (3) |
|
The availability of
freshwater is an essential condition for the existence of life on the continents.
As source of drinking water rain-, surface- and ground water with low mineralisation
can be used according to the legal standards for drinking water. In coastal
areas the fresh groundwater is underlain by the heavy mineralized sea water.
The two liquids remain separated by the interface. Its location is given
by the state of hydrodynamic equilibrium (M.K.Hubbert, 1940). Within the
continents saline groundwaters (and brines) are present within sedimentary
basins and the deep crystalline basement. In regions of semi-arid to arid
climate shallow saline groundwaters can be formed under unfavorable or
disturbed natural conditions of equilibrium of the different components
of the water cycle. Therefore it is of vital importance not to disturb
the natural conditions by agricultural land use practices and groundwater
exploitation in such a way that derogation of landscape and/or freshwater
containing aquifers results by the process of salting or of saltwater intrusion,
respectively. |
Wäffler, H. |
Kernphysik an der ETH Zürich
zu Zeiten Paul Scherrers (no Abstract) |
143-176 (3)
|
Jetzer, P. |
Dark Matter in the Universe |
181-206 (4)
|
|
A number of astronomical
observations show that at least 90% of the gravitating matter in the Universe
is dark. We discuss in some detail the evidence for this and present also
arguments for the hypothesis that the average density of the Universe might
well be close to the critical value. In this likely case 99% of the matter
must be dark and the main content of the Universe consists of unknown nonbaryonic
forms of matter. The questions of the nature, origin and distribution of
dark matter belong to the most important issues of present day astronomy
and fundamental physics. |
König Gabriele
M, Wright Anthony D, Oechslin Stephan M, Sticher Otto |
Natural products from marine organisms
and higher plants. |
207-225. (4) |
Natural products play
an important role in drug discovery. The isolation of bioactive compounds
depends on the careful selection and fractionation of biological material.
Consideration of these criteria led, in our laboratory, to the isolation
and structure elucidation of new and/or biologically active natural products
from samples belonging to a wide range of taxa. The natural products discussed
provide an insight into some of the characteristic secondary metabolites
to be found in marine algae, sponges and higher plants of the family Papaveraceae.
Explanations concerning the structure elucidation of compounds focus mainly
on the use of two-dimensional NMR-techniques. Sensitive in vitro bioassays
were applied to evaluate the biological activity of the isolated natural
products. Compounds with antimalarial, antiinflammatory and cytotoxic activity
are discussed. |
Endress Peter K |
On Christian Konrad Sprengel's
work two hundred years after its publication |
227-233. (4) |
|
In 1793 Christian
Konrad Sprengel's classical work «The Discovered Secret of Nature
in the Structure and Fertilization of Flowers » appeared (five years
earlier the book had been announced for the first time in the «Magazin
für die Botanik», published in Zurich, the first botanical journal
of the world). Sprengel's work initiated floral biology as a scientific
discipline. Sprengel investigated almost 500 species of flowering plants
and discovered the pervasive role of insects in the pollination of flowers;
he showed many fundamental adaptations in the structure of flowers to these
symbioses. Floral biology has developed and expanded in the last decades.
But due to the worldwide threat of biodiversity it becomes increasingly
apparent how many aspects of these symbioses are unknown, especially on
the level of entire ecosystems and larger scale diversity. |
1991 136th. |
|
|
Börner, G. |
The Spatial Distribution of Galaxies |
1-12, (1) |
|
During the last few
years redshift measurements of galaxies have revealed a variety of spatial
structures in the distribution of the lumious matter. The difficulties
to understand these distributions in the framework of a cosmological model
stem from the contrast between this inhomogenous distribution and the remarably
uniform cosmic microwave background. A special model, the so-called pancake
model is briefly described. |
Bonsen K J M |
Vessel occlusions in hardwoods. |
13-50 ( 1) |
|
Vessel occlusions
in 65 species (45 genera, 24 families) have been investigated. Occurrence,
types and morphology are given, relations between occlusion type and tree
species, initiation (causes, circumstances), development, function, technological
consequences and the prevention of vessel occlusions are discussed. The
study is based on a literature survey. Swiss grown woods show two main
types of vessel occlusions: tyloses and gums. Whether a plant produces
gums only, or gums and tyloses depends on the gap size of the vessel-parenchyma-pits;
is this larger than 3 mu-m tyloses are produced. In evolution the first
angiosperms occluded their vessels with tyloses. Later the pit sizes decreased
and the plants occluded their vessels by gum plugs. Because of the increasing
vessel diameter plants had to return to tylosis formation secondarily.
Tylose formation is initiated by oxygen, hormones (endogenous or microorganisms'
hormones), or a break-down of the osmotic regulation of the parenchyma
cells. Occlusion of vessels only takes place when the parencyma cells are
vital enough, when there is sufficient water and starch available and when
the temperature range is right. Taking part in the compartmentalization
is the primary function of vessel occlusions. |
Zbinden Gerhard |
Toxicological assessment of drugs
obtained by biotechnology. |
51-65 (1) |
|
Through application
of fundamentally new methods of biotechnology it has become possible to
manufacture pure. biologically highly active proteins and polypeptides.
With these substances exciting new therapeutic possibilities were created.
For the experimental assessment of safety of biotechnology product. many
new problems have arisen. The major ones are the species-specificity of
many of these agents that normally occur only in humans, and the immunological
processes set into motion when these proteins and polypeptides are administered
to laboratory animals. Nevertheless. experience gathered up to date indicates
that at least part of the adverse effects of biotechnologically manufactured
drugs can be detected in animal experiments. However, it is necessary to
abandon the conventional safety testing methods and to develop testing
strategies that take into consideration all biological and chemical characteristics
of each individual new drug. |
Dimroth Peter |
Energy conservation in anaerobic
bacteria. |
77-91 (2) |
|
The first forms of
life on the earth were anaerobes, because an 02-containing atmosphere
formed only after the development of photosynthesis. Extended 02-free
areas exist even on earth today, which are occupied by anaerobic microorganisms.
These organisms can degrade a broad spectrum of organic compounds, but
use only a few mechanisms for the conservation of biological energy. These
mechanisms are in part identical or similar to those of their aerobic counterparts.
A huge number of anaerobic bacteria synthesize ATP entirely by substrate-level
phosphorylation. Others use a chemiosmotic mechanism for ATP synthesis.
The electrochemical gradient of protons required as driving force for the
ATPase is created by an anaerobic respiratory chain, in which oxygen as
terminal electron acceptor is replaced by a less strong oxidant, e.g. sulfate
or sulfur. In Propionigenium modestum, an electrochemical Na+ion
gradient is created over the membrane by decarboxylation of methylmalonyl-CoA,
which is used for ATP synthesis by a particular Na+-translocating
ATPase.
Oxalobacter formigenes in a 1:1 exchange of oxalate for
formate forms an electrochemical proton gradient which is used for ATP
synthesis. The exchange is driven by the decarboxylation of oxalate, developing
a concentration gradient over the membrane which for oxalate is directed
from the outside to the inside and for formate from the inside to the outside. |
Gassmann F. |
The most important findings related
to the greenhouse problem. |
93-104 (2) |
|
The physical basis
of the greenhouse effect can easily be understood qualitatively and quantitatively
by a few simple relations. The scientific conclusions of the World Climate
Conference 1990, which are identical with the IPCC report, can be reproduced
and critically analysed. We must be aware that the long range climate forecasts
probably have to be corrected towards higher temperatures. Even without
this possible intensification of the problem, we have to judge future climate
change on the paleoclimatological background as dramatic in respect to
its amplitude and also to its rate of change. Atmospheric concentrations
of carbon dioxide and methane together with temperature variations during
the last ice age suggest an instable global climate system amplifying small
perturbations. In spite of many scientific uncertainties, it is clear today,
that planet earth is going to execute a major transient having important
implications on its development for a very long time. If this anthropogenic
process will be in favour of mankind and the whole biosphere is uttermost
questionable. |
Merz B |
The fruit-flies of the town of
Zurich (Switzerland) (Diptera: Tephritidae). |
105-111 ( 2) |
|
31 fruit-fly species
(Diptera: Tephritidae) were found in the town of Zurich between 1987 and
1990. Crepis taraxacifolia is a new host plant for Tephritis matricariae
(LOEW). The phenology, host plant relationships and the association of
the flies to different habitats are discussed. |
Schwyzer M |
Which came first, the virus or
the host? |
113-130 ( 2) |
|
Neither the viruses
nor their pathogenesis have left a fossil record. No existing virus isolates
are more than 80 years old. Yet, epidemiology and molecular analysis of
contemporary viruses infecting animals and man contribute to an increasingly
clear view of their distant predecessors. Viruses and viroids also inspire
speculation about their possible involvement in the origin of life, because
they are among the simplest entities carrying instruction for their own
multiplication. However, since the rate of virus evolution is roughly a
million times higher than that of the host, this question may never lead
to a conclusive answer. |
Sticher H |
Conservation of our natural resources:
The soil case. |
137-149 ( 3) |
|
Soil protection includes
all direct and indirect measures which support the conservation of the
different soil functions in a balance proportion. In order to preserve
the soil as the basis of life and as an adequate habitat of mankind, animals
and plants, it is essential to keep a sufficient area for primary production,
to secure fertility and productivity of the soil at long sight, to maintain
adequate nature protection reserves and to limit land consumption. Following
general considerations about the endangering of soil quality by human activities,
the soil protection policy of Switzerland is presented, present regulations
are critically reviewed and somm supplementary measures are suggested. |
Apel K |
The light-dependent control of
chloroplast development in higher plants. |
151-161 ( 3) |
|
In the absence of
light higher plants form etiolated seedlings whose plastids are devoid
of chlorophyll. In these socalled etioplasts the biosynthesis of chlorophyll
leads only to the formation of the immediate precursor of chlorophyll,
to protochlorphyllide. The subsequent reduction of protochlorphyllide to
chlorophyllide requires light. Upon illumination of etiolated higher plants
chlorophyll accumulation starts and at the same time the photosynthetically
active membrane system of chloroplasts develops. The light-induced transformation
of etioplasts to chloroplasts is controlled by at least two different genetic
systems. To a lesser part plastid proteins are encoded by the plastid DNA
and the resulting mRNAs are translated at plastid-specific ribosomes. The
majority of plastid proteins are encoded by nuclear genes and are synthesized
in the cytosol as higher molecular weight precursor polypeptides that are
transported into and processed within the plastid compartment. The interaction
of the two genetic systems is under the control light. The effect of light
is mediated by at least two distinct photoreceptors. Phytochrome as one
of these photoreceptors controls the transcription of nuclear genes that
encode light-dependent plastid proteins. The second photoreceptor, the
protochlorphyllide reductase, catalyzes the light-dependent reduction of
protochlorophyllide to chlorophyllide within the plastid and affects also
the light-dependent chloroplast development. The interaction of these photoreceptors
has been studied in mutants in which the function of either one of the
two photoreceptors has been abolished by mutations. |
Turner H |
Inventory and threat situation
of the molluscs in the canton Zurich, Switzerland. |
163-181 ( 3) |
|
Almost 100 years after
the first catalogue of the Zurich molluscs, which comprised approximately
100 valid species, its revised edition is presented. During the last two
centuries c.160. Recent species of molluscs (106 land snail, 33 freshwater
snail and 21 bivalve species) were recorded in the canton Zurich, i.e.
60% of the number of Recent molluscs species in all-Switzerland. It is
likely that 13 additional species (mainly slugs) may be detected through
intense search. Six species are supposed to have disappeared from the canton
Zurich since a prolonged period, and ten additional species could only
be detected as fossils in deposits of the Quarternary, Gyraulus laevis
and Unio crassus are rated to be in danger of extinction (threat-category
1), whereas eight species must be classified as strongly threatened (threat-category
2). No less than 47 additional species appear to be threatened due to decline
and destructiuon of their habitats or to their rarity (threat-categories
3 and d4). Altogether, 40% of the mollusc species in the canton Zurich
either have disappeared for appear to be endangered. Separately treated
are eight adventitious species of which only a few became established.
Five species immigrated (or were imported) during very recent times and
are expanding. In conclusions, on the basis of the Swiss mollusc data bank
some habitats are designated which are in need of protection because of
occurrence of threatened or rare species. |
Blum H |
Greenhouse effect and plant growth. |
189-206 (4) |
|
Calculations of present
day climate with models indicate great errors. These models are not validated.
They proved to be very sensitive on variations of different cloud parameters
which have not been determined yet with sufficient accuracy. Some sensitive
processes are not yet included. The model predictions are not reliable.
The increase of global temperature for the last 100 years has been evaluated
with questionable assumptions and coffections. The value of approx. 0.5
0C is within natural variation of climate. The amount and the
geographical pattern of this increase don't agree with the predictions.
The antarctic tee-cores contradict the greenhouse-relevant cause-effect
relation. The CO2 increase promotes plant growth mainly by two
effects: A CO2 doubling increases photosynthesis significantly,
such that a growth increase of approx. 25-100% is effected. The optimum
temperature of growth increases about 2 0C, thus plants would
even profit from a moderate temperature increase. A decrease of transpiration
which can cause a growth increase, too. Water use efficiency is approx.
doubled, i.e. with limiting water supply, plant growth would nearly double.
These effects all continue to increase beyond a CO2 doubling.
The demand for a reduction of CO2 production is reasonable for
the most industrialized countries but it would be catastrophic for the
developing countries. |
Egloff F G |
Permanence and change in the flora
of Laegern. |
207-270 ( 4) |
|
The geological and
topographical diversity of the region of Laegern (Switzerland, cantons
Aargau and Zuerich) shows a flora rich of vascular plant species which
is typical for the lowland of Switzerland and for the northeastern Jura
Mountains on the one side, specific for this region on the other side.
The landscape has undergone an intensive change since the turn of the century,
which shows an influence on the flora. The past flora of a number of areas
and localities and of the whole region is partially reconstructed by the
study of old herbaria, excursion notes and of floristical publications,
and comparisons with the present state are made. Factors of threats and
possibilities for preserving the floristical diversity and the local historic
species are debated. |
1990 135th. |
|
|
Niederer P |
High technology in medicine. |
1-16 (1) |
|
Present diagnostic
methods are aimed on the one hand at allowing for a preferably noninvasive
application and, on the other hand, at being specific for a certain disease.
An unspecific and useless application should a priori be avoided. Many
procedures which are available or still being further developed today and
which fulfil these requirements to a high degree, are in essential need
of high technology. In many cases a procedure could not even be envisaged
without the use of high technology.
Computed tomography, ultrasound methods and new procedures
of computerassisted evaluation of x-ray images serve as examples to document
the importance of high technology. Furthermore, in therapy improved treatment
methods become available due to the use of advanced technology. A well-known
example for such a development is lithotripsy with the aid of mechanical
shock waves. |
Burga C A |
Vegetation history and paleoclimatology. |
17-30 (1) |
|
The introduction gives
a short overview to the palaeobotanical and palynological research in Europe.
The main important palaeoclimatological methods are the following: Pollen
analysis, dendrochronology, oxygen isotopes analysis, CO2 analysis, glacier
oscillations, löss stratigraphy, weathering, erosion and accumulation
of soils, sea/lake level fluctuations, planktonic foraminifera, fossil
beetles assemblages, etc. The main problems of palaeoecological reconstructions
with pollen analytical methods are discussed. The following points are
important: Natural succession, soil forming phases, plant immigration,
immigration pathways and possibilities, concurrence, vertical vegetation
zonation.
Late Würmian and holocene Swiss alpine climate oscillations
and timber-line fluctuations since the Alleröd-Interstadial are discussed.
In the western Central Alps the timber-line increased during 1000 years
at the beginning of Holocene at about 500-600 m. During the post-glacial
climate optimum (Atlantic) the timber-line reached its highest extension
at about 2300 m above sea level, and the snow-line reached up to 3100 m.
The most important climatic deterioration during the Boreal (8500-7200
years B. P.) is characterized in the Central Alps by a marked recession
of Pinus cembra (Oberhalbstein-/Schams-/Venediger-Oscillation). This recession
has been recorded in several pollen diagrams in the Grisons, the Valais,
the Bernese Alps, the Salzkammergut, the Hohen Tauern, and the Southern
Tyrol.
Boreal dry periods may explain the Pinus cembra recession
as a result of frost dryness. At the end the paper gives an outline of
the development of the Swiss central alpine forest belt and the snow-line
since the late Würmian. |
Nievergelt B |
Ecological strategies as a model
to understanding problems of animals and man in a particular environment. |
31-46 (1) |
|
With the well-known
r-K-strategies we have a simple ecological model, that is helpful in efforts
to understand complex systems such as a particular species of animals or
plants in their specific environment. As examples the Kingfisher, the Roe
deer and the Alpine ibex are treated. In addition - although in a more
speculative manner - human society is considered for which a partial and
therefore especially critical change in strategy is described.
In applying a simple ecological model to reality, which
is always more complex, we can never expect a complete correspondence.
However, it is shown that the value of a model becomes particularly evident
in the analysis of those characters that do not coincide between reality
and model. |
Stettler, P |
Martin Wagenschein's Nature-Philosophical
Approach |
47-61 (1) |
|
In the introduction
we briefly describe the pedagogical work of Martin Wagenschein, in whose
centre stands original understanding and precise thinking. The process
of understanding physics can only succeed if it is not regarded without
certain presumptions, but as limiting itself on the measurable. It is this
self-limitation of their subject that many physicists seem do disregard,
if they want to interpret a meaning of the universe from its unified theory.
Wagenschein's philosophical interest centres on the creation of physics
from the living world. This epistemological path is described in the example
of a cord's sound. On the question about the nature of light it is pointed
out in a Wagenscheinian manner that light as such is not visible. By this
means even the beginner will realize the parabolic character of light-waves
and photons and their complementary relationship. Wagenschein sees the
true pedagogical value in the understandability of nature, in the discovery
of an enigmatic order in the universe. |
Hitzig, W. H. |
Long-term Observations of Diseases
in Childhood |
73-88 (2) |
|
In my fare-well lecture
on retiring from the Kinderspital Zurich, I discussed with the students
longterm observations in patients with blood diseases. As a common denominator
I pointed out the decisive influence of medical knowledge and skills on
quality of life or on survival of these children. - The patients presented
the following problems:
1. A hereditary hemoglobin anomaly (Hb Zurich): the bearers
of this gene are essentially asymptomatic, but suffer severe hemolytic
attacks after ingestion of sulfonamides and other drugs. - This is a typical
example of an iatrogenic disease.
2. A cancer of the kidney (nephroblastoma, Wilms-tumor)
which may help to understand the pathogenesis of malignant degeneration.
This child was cured by combined therapy, but toxic side-effects of a drug
damaged the myocardium and later necessitated a heart transplantation.
3. A case of leukemia in a 4-year-old girl was successfully
treated 23 years ago. She could later lead a normal life, got married and
gave birth to two normal children.
4. A boy with familial congenital severe combined immunodeficiency
syndrome (SCID) was successfully treated by bone-marrow transplantation
two years ago and is now normally developped. |
Klingler J, Kunz P, Buser A |
The vector nematode Xiphinema
diversicaudatum and the arabis mosaic virus of strawberries on the Swiss
plateau (Switzerland). |
89-96 (2) |
|
The ditribution of
X. diversicaudatum in Switzerland is shown in a map (figure). Compared
with earlier maps new finds have been added, but the known geographical
distribution pattern remains unchanged: East of the Walensee and Zurichsee
basins and of the Limmat valley, Switzerland remains void of any finds
of this species. According to Sturhan, the same is true for the adjacent
south German area. X. diversicaudatum has been found west of the just mentioned
geographical axis exclusively. The hypothesis therefore is maintained that
this species is not occurring in soils originating from deposits of the
eastern Alps which are rich in chalk, whereas it occurs in soils derived
from deposits of the central and western Alps, which are rich in silicates.
The occurrence of the arabis mosiac virus (AMV), which is vectored by X.
diversicaudatum, is strongly related to the abundance of the vector. The
virus has always been found if populations exceeded 400 nematodes per liter
of soil; it has never been detected in places where vector densities were
below 100. In between, the virus has sometimes been found and sometimes
not been found (table). These relations enable prognoses to be made regarding
the risk run by strawberry plantation to the damaged by the arabis mosiac
virus. The occurrence of X. diversicaudatum is related to soil parameters.
It was confirmed to clearly acid to neutral soils. Among the soil types,
most findings were made in sandy loam and - less frequently - in loam. |
Eiberle K |
The importance of forests for
the animal kingdom |
117-127 (2) |
Hasler F |
Perspectives on the pathogenesis
of rheumatoid arthritis. |
129-138 (3) |
|
Rheumatoid arthritis
(RA) is a complex disease of unknown etiology in which genetic, hormonal,
and immunologic factors interact to produce joint and systemic manifestations.
Both the humoral and cellular arms of the immune response appear to participate.
Locally produced antibodies complex with an inciting antigen, yet to be
identified, within the joint and activate the complement system, resulting
in articular inflammation mediated primarily by polymorphonuclear leukocytes
and their products. Chronic inflammatory cells then produce soluble factors
that induce both tissue destruction and inflammation. RA is an example
of a disease in which the central immune recognition event involves CD4
lineage helper T cells interacting with polymorphic class II HLA molecules. |
Mancktelow, Neil |
Displacement, Deformation and
Fabric of Rocks |
139-154 (3) |
|
Deformation structures
can be observed on all scales within orogenic zones such as the Alps, where
two continental land masses have collided. They represent the final form
acquired due to relative movements of the rocks over millions of years,
and their geometry is relatively well known from detailed field studies.
The current challenge is to attempt a reconstruction of the movement history,
i.e. the kinematics, from the available field data. To this end, various
forms of scale models are particularly useful, as they allow study of the
progressive development of deformation structures. The models may be smaller-scale
field examples of major structures, rock mechanics experiments in which
time, stress and temperature are scaled but the rock material is the same,
models using analogue materials (e.g. paraffin wax), or mathematical models.
The results of modelling can then be applied to field studies: as an example,
in interpreting movements on major fault zones such as the low-angle extensional
normal fault which is well-exposed between the Simplonpass (Valais) and
Domodossola (Italy). |
Schonle E J |
The child with diabetes mellitus:
Between immunology and psychology. |
155-168 (3) |
|
Childhood diabetes
(Type-1-diabetes) is based on the lack of the essential hormone insulin.
It is now widely accepted, that the development of Type-1-diabetes is the
consequence of an autoimmune destruction of the insulin-producing beta
cells of the pancreas. However, a genetic predisposition is required. In
addition recent results from molecular genetic research suggest a susceptibility
gene in the HLA-region on chromosome 6. Trigger substances inducing the
initial beta cell destruction are not known today. Finally all insulin
producing cells are destroyed, life long insulin replacement therapy cannot
be circumvented. Optimal treatment delays or prevents diabetic late complications.
Precondition for optimal therapy is an extensive education of the child
an the parents, an exact diet with known amounts of carbohydrates, multiple
insulin injections and home blood glucose monitoring. Prevention of the
autoimmune destruction is not yet possible up to now. |
Merkle H P |
Delivery systems for transdermal
therapy: Approaches, chances and limits. |
169-190 (3) |
|
There are not many
fields in drug formulation where the complexity of modern pharmaceutical
research can be so clearly demonstrated as by the sequence of ups and downs
taking place in the field of transdermal delivery system development. The
basics to this area include the anatomy and biochemistry of the skin, the
polymer chemistry of relevant polymers, the manufacturing of laminated
polymer patches and the pharmacokinetics and pharmacodynamics of controlled
delivery of drugs. Equally important are questions about the effect of
so-called absorption enhancers on the integrity of the skin, the mechanisms
of transport control in laminate systems and how to affect the thermodynamic
activity of drugs in relevent carriers. The essential question, however,
is concerned with the safety and the risks of such therapy. This work is
aimed to illustrate the need for a multi-disciplinary approach to make
progress become possible in spite of rather narrow boundary conditions. |
Siegmann H C |
Combustion aerosols. |
197-219 (4) |
|
Progress in many areas
has led to an improved knowledge of the deleterious effects of the primary
(smoke) and the secondary (smog) combustion aerosols on human health, weather,
and plants. Physical characterization and measurement of the combustion
aerosols provides the basis for urgent improvement of the air quality.
The notoriously difficult soot is built from homogeneous spherules, the
primary tar particles, on which poisonous chemicals are adsorbed depending
on the type and mode of operation of the combustion device. Soot particles
are agglomerates of hundreds of primary tar particles, yet their optical
absorption is adequately described by the concept of fractal structure
despite the bizarre shapes, and their size range in the transition between
the applicability of Mie- and Rayleigh-theory. The adsorbates of the soot
particles may be classified according to their desorption temperature by
photoelectric charging. Additionally, the photoelectric aerosol sensor
offers a simple way to dynamically determine the total mass of the carcinogenic
polycyclic aromatic hydrocarbons (PAH) adsorbed on the particles. Legislature
should thus be able to generate new rules for the survey of combustion
devices that are better adapted to the present needs and state of knowledge. |
Grauer R |
The disposal of highly radioactive
wastes: Chemical aspects. |
221-238 (4) |
|
The safety of the
storage of highly radioactive wastes relies on a system of sequential technical
and natural barriers. Wastes from reprocessing of fuel elements are immobilised
in glass and the glass is embedded in steel canisters of 25 cm wall thickness.
The disposal tunnels are backfilled with swelling bentonite clay. The backfill
has approximately one meter thickness and represents an efficient transport
barrier because of its low hydraulic conductivity and goood sorption properties.
Very long-lived radionuclides, only, survive transport in the backfill.
Some of these have low solubilities in groundwater. For most of them migration
through host rocks and overlaying sediments is retarded by adsorption.
For all of them matrix diffusion contributes to retardation. Safety assessments
have to prove that dose exposition resulting from disposal does not exceed
the regulatory limit. For a reliable safety analysis knolwedge of long-term
performance of technical barriers and chemical behaviour of radionuclides
along a potential migration path is necessary. In this, a phenomenological
description is insufficient; required is the understanding of relevant
reaction mechanisms. |
Vonarburg C, Ruoss
E, Burga C A |
Bioindication with epiphytic lichens
on horse-chestnut trees around Lake Zurich (Switzerland). |
239-258 (4) |
At sites close to
the shore along Lake Zurich the lichen vegetation has been studied on 131
horsechestnut tree-trunks (Aesculus spec.). A lichen index calculated from
the total cover and the number of species showed in the investigation area
a clear gradient to a better developed lichen vegetation towards southeastern
direction. Even at sites with a high lichen index, species sensitive to
air pollution are rare and show little cover. Furthermore, a clear tendency
to a better developed lichen vegetation has been made evident from sites
close to the center towards sites which are situated outside urban areas.
Similar trends are shown by the zonation into six lichen zones including
further parameters like damage and vitality of lichens. According to the
results of zonation and lichen index, there is a decreasing concentration
of lichen damaging pollutants from the northwestern towards the southeastern
part of the investigation area. Compared to the results of the lichen studies
the immission data of technical measurements indicate a dominant role of
sulphure dioxide as lichen damaging pollutant whereas a synergistic effect
together with other substances is very probable. |
Schiess H |
Reed stands as habitat islands
of birds. |
259-265 (4) |
|
The influence of various
ecological parameters on the occurrence, species diversity, and species
frequency of breeding birds was investigated in reed stands of the Lake
of Zurich and Obersee, Switzerland. The homogeneous and sharply delimited
reed stands constitute habitat islands in the surrounding landscape. A
total of 212 reed stands were mapped photographically and their form, size,
and structure were determined. Three types of reed stands could be distinguished,
each with characteristic features and typical avifauna. A survey of breeding
birds in these stands revealed 1816 pairs of the following 13 species,
listed in order of decreasing frequency: Grebes, Coots, Reed Warblers,
Reed Buntings, Marsh Warblers, Great Reed Warblers, Moerhens, Mute Swans,
Little Grebes, Water Rails, Savi's Warblers, Gray Herons, and Little Bitterns.
The relationships of site parameters are discussed, and detailed observations
are presented on Little Grebes, Little Bitterns, Reed Buntings, Marsh Warblers,
Reed Warblers, and Great Reed Warblers. Statistical analysis showed area
of the reed stand to be the single most important site parameter. |
1989 134th. |
|
|
Schneebeli M, Kuettel M, Faeh
J |
Three-dimensional development
of a peat bog on a slope in Toggenburg, Switzerland. |
1-32 (1) |
|
In connection with
the restauration of a peat bog on slope the development of the peat was
investigated with palynological methods. The bog is situated in the Upper
Toggenburg (Switzerland) and is partially exploited or drained. A boring
core for the reference pollen profile was taken at one of the deepest sites
of peat. Every 5 to 10 cm a pollen sample was counted. Additionally 10
samples are radiocarbon dated. To determine growth and spread of the peat
on a grid with 50 m side length at 43 sites, samples were taken at the
interface between peat and underlying mineral soil and on two transsect
in three depths. The history of vegetation of the mire of the past 10,000
years, as well as of the region, could be interpreted by means of the reference
profile. Calculation of the pollen accumulation rate enhanced the interpretation
in the early phases of development. The visual stratification of the percentage
pollen diagram was used to relate the basis and transsect samples to the
biostratigraphical zones. In a second approach the basis and transsect
samples are dated through numerical correlation between reference profile
and sample. The resulting date was more precise than the visually related
sample where the pollen percentages are appropriately transformed. An estimation
of error by application of different correlation methods showed that 90%
of the samples could be dated within +- 880 y. The dated samples are visualized
with maps. The bogs has spread from two centres at the edge upward. During
this spread it climbed over several steps. Although the horizontal spread
ceased about at 0 A.C. because of geological reasons, no decrease of the
vertical growth is visible until the 19th century. |
Niederer, U. |
Comets, Moons, New Stars: the
role of Observation in the Copernican Revolution |
33-54 (1) |
|
While observations
played a minor role for Copernicus himself they later influenced considerably
the improvement and the reception of the Copernican system. Several types
of influence may be distinguished. The observations made by Tycho Brahe
were the primary motive for Kepler to modify and develop the system. The
newly appeared stars of 1572 and 1604 and the comet of 1577 showed that
changes in the heavens were possible, hence the Aristotelian views on the
nature of celestial bodies, which formed the basis of traditional astronomy,
could no longer be correct. The moons of Jupiter, discovered by Galileo
in 1610, demonstrated that there were other centers of motion besides the
earth, which in turn made the heliocentric system more credible. Newer
and better observations made it ever more obvious that in applicability,
too, the new astronomy was superior to the older one. |
Scharfetter C |
Medicine and anthropology. |
56-66 (1) |
|
Science (and therefore
medicine too) is a culturally determined system of cognitive structuring.
A holistic approach to medicine should take into consideration somatic-physiological,
psychological, social as well as transpersonal perspectives towards illness
and healing. The ubiquitous suffering creates a multitude of healing offers.
Western academic medicine has developed as a profession with claim for
monopoly as the only valid healing system, based on empirical positivism
of natural science. Common factors appear to be operative in various healing
procedures. |
Landolt E |
Environmental tolerance test:
Introduction and conclusions. |
67 (1) |
Schmid W A |
Basic principles of methodological
procedure in environmental tolerance tests. |
68-73 (1) |
Margulies H P; Trachsler H |
First experiences with administering
environmental tolerance testing. |
74-80 (1) |
Duetsch H U |
The Antarctic ozone hole: An anthropogenic
feature. |
85-108 (2) |
|
The very complex modern
photochemical theorie of atmospheric ozone is described in which odd oxygen
destruction is predominantly produced by catalytic cycles with reactive
radicals. It is demonstrated that the observed ozone distribution can only
be understood on the basis of a tight coupling between similarly complicated
chemical and transport processes.
The ozone hole which developed in the Antarctic spring
since the late seventies is produced by anthropogenic chlorine which is
activated in the extremely cold air at the end of the polar night in the
lower stratosphere predominantly by heterogeneous reactions. This process
happens in an air mass which covers most of the Antarctic continent .and
which is due to the prevailing dynamic conditions practically isolated
from the surroundings. The active chlorine destroys after the return of
the sun the ozone by catalytic cycles which are more complicated than these
of the normal photochemistry. There is a tight relationship (feed back
mechanisms) between chemistry and circulation. |
Bolliger T, Eberhard
M |
New fossils from the upper freshwater
molasse of the Hoernli region (Eastern part of Switzerland). |
109-138 (2) |
The Molasse sediments
of the Hoernli fan have been divided by different authors into lithologically
different sequences and thus widely correlated. This artificial division
is not satisfactory and of minor value due to the fast changing sedimentary
conditions within fluvial deposits. Fossils were only occasionally found.
E. Letsch 1899 first described the occurrence of a thin coaly marl with
fossil leaves on Chlihoernli at 930 m. In 1986 M. Weidmann (Jongny VD)
successfully prepared some other dark marls for Microfossils. More recently
our systematic search for fossils in that region lead to the discovery
of several additional horizons in the profile. A provisional biostratigraphy
of the uppermost fossil-containing layers indicates the presence of MN
6-7. (MN means Micromammal-Unit of Neogene age). Phytozonation indicates
that OSM 3a-3b are present. The plant associations of Leiachertobel and
Chlihoernli are that of modern mixed mesophytic forests. Climatically,
both Chlihoernli horizons can be described as warm temperate, with a mean
annual temperature of 15-17 degree C and a mean annual precipitation of
over 1300 mm. At Leiachertobel the provisional results indicate a slightly
cooler climate. Paleotopography at Chlihoernli (930 m) was rather flat
and at or lower than 350 m above sea level, whereas at Chlihoernli (1000
m) the increase of mesophytic and mountainous species indicates an accentuated
paleorelief. |
Specker, E. |
Logic or the Art of Programming |
139-150 (2) |
|
The fundamental ideas
of logic programming are explained by considering a puzzle (the Towers
of Hanoi). The possible positions of the puzzle form a graph, two positions
being joined by an edge if they can be transformed into one another by
a legal move. Two realizations of this graph are introduced: one in our
material world with the help of a copying machine, the other in the ideal
world of Herbrand with the help of logic programming. |
Potrykus I |
Gene technology in plants. |
165-174 (3) |
|
Methods have been
developed during the recent years which open up the possibility to transfer
isolated genes into somatic plant cells and to regenerate subsequently
complete plants from these genetically altered cells. Such "transgenic"
plants differ normally from the original plants only with regard to the
novel character caused by the gene added. The "foreign" gene can originate
either from a plant or from other organisms. As soon as it is integrated
into the genome of the acceptor cell it behaves exactly like other original
genes of the host plant. The foreign gene can also be changed prior to
its transfer, e.g. by an alteration in the regulatory signals which decide
where and when in the plant the gene will be activated. Gene technology
thus offers possibilities for precise and predictable alterations of plants.
This is understood by part of the population as great opportunity, by others
as a big danger. Both views probably exaggerate. It is rather difficult
to construct dangers on the basis of transgenic plants, and the possibilities
for plant improvement via gene technology are rather limited. |
Kucera L J |
Potential applications of NMR
tomography in wood research. |
175-196 (3) |
|
The nuclear magnetic
resonance tomography is a non-destructive method, which renders two dimensional
figures of water distribution in wood. The potential applications of this
method in forest and wood research are summarized. In the introductory
chapter, the role of the water in tree physiology, wood science and wood
technology is outlined. A critical review of the established methods of
the determination of the water content in wood is presented. The fundamentals
of the nuclear magnetic resonance tomography are briefly outlined. The
advantages of this new method are visualized by numerous examples. In conclusion,
a list of the potential uses of the nuclear magnetic resonance tomography
in the research fields of tree physiology, wood science and wood technology
is presented. |
Mittelstrass, J. |
Copernican or Keplerian Revolution?
- Kepler's Cosmology, Philosophy and Methodology |
197-215 (3) |
|
In the history of
science and ideas the name Copernicus stands for a fundamental change in
theoretical and methodological matters. Here, the fact is overlooked that
the Copernican programme is in reality a conservative one and that the
revolution in question takes place no earlier than within the framework
of the Keplerian astronomy. Copernicus tries to revalidate an old research
programme in astronomy, whereas Kepler breaks with this programme and starts
with a new development which, from the point of view of physics too, leads
far beyond classical astronomy. In order to illustrate a «Keplerian
revolution» attention is paid to Kepler's kinematical and dynamical
explanations. Further passages deal with the Keplerian achievements, the
harmonies of the cosmos and the Keplerian unity of philosophy and science
of nature. |
Wolters G |
Fourteen philosophy of science
theses on the problem of new kinds of forest damage. |
216-223 (3) |
Lubini-Ferlin V |
Ecological survey of streams within
the city of Zurich (Switzerland). |
229-250 (4) |
|
The habitat structure
of 84 streams with a total length of 70 km was surveyed from 1986 to 1988
within the city limits of Zurich. The faunal composition of ten selected
streams was studied in more detail. Twelve species of mayflies, fourteen
species of stoneflies and 48 species of caddisflies were found. For the
first time in the canton of Zurich, I recorded the occurrence of species
of mayfly, Baetis scambus and Ecdyonurus helveticus, and found larvae of
the dragonfly Cordulegaster bidentatus at two new localities. Overall,
109 taxa were recorded during the study. In general, more species were
found in large and highly structured streams with a regular water flow
than in small streams with a periodic water flow. Waterweeds in high abundance
were found in Sagentobelbach, Dorfbach Affoltern and Katzenbach. The evaluation
revealed that eighteen out of 84 streams were in a satisfactory ecological
condition. A comparison of my fauna list with data from the end of the
last century suggests that the fauna composition of stoneflies and caddisflies
in Wehrenbach and Stockentobel has changed over this period. |
Straumann, N. |
Neutrinophysics and Supernova
Explosions |
251-280 (4) |
|
At the end of the
thermonuclear evolution of a massive star the burned out central region
becomes unstable and collapses in almost free fall. Thereby a neutron star
or a black hole is formed. The exterior parts of the progenitor star may,
under certain circumstances, be expelled by a powerful shock wave. This
cosmic firework appears then as a supernova. By far the largest part of
the energy released in the collapse is, however, radiated away in a gigantic
neutrino pulse. This neutrino radiation was the first time detected in
underground laboratories a few hours before the supernova SN 1987A flared
up in the Large Magellanic Cloud. This enabled us to test quantitatively
our theoretical ideas on gravitational collapse and neutron star formation.
Detailed observations of the further evolution of SN 1987A are of invaluable
importance for the study of stellar evolution, nucleosynthesis, and the
physical processes at the birth of a neutron star. The supernova 1987A
in the Large Magellanic Cloud will be a major focus for astrophysical research
for many years to come. |
1988 133th. |
|
|
Bolliger T, Gatti H, Hantke R |
Geology and paleontology of the
Zurich Oberland (Switzerland). |
1-24 (1) |
|
New scientific research
within the Zurich Oberland may add some new aspects to the knowledge of
Molasse and Ice Age. Several nodular limestones are explained as calcicrusts,
built up under semi-arid conditions. Coarse, chaotic conglomerate sequences
may be interpreted as sediments of cooler climates. The finer grained homogeneous
conglomerates are still thought to be of fluvial genesis. The fossil remains
of plants and mammals found in marls indicate warmer climates than today.
The mollusks of the Upper Freshwater Molasse prove that there were only
a few places within the region with stagnant waters, such as lakes and
ponds. The Upper Marine Molasse is a 100 m thick sequence of sediments,
built up during a short period of a marine influx. It shows sedimentary
structures due to rapid changed depositary conditions. Dense forests protected
the landscape from erosion during warmer periods; valleys must have been
deepended in colder times. Toss and tributaries eroded along thrusts, faults
and regions of weak and soft lithologies. The Upper Lake Zurich basin is
the remainder of a broken up anticlinical system. The main events from
the Molasse times to late Ice Age shaped the landscape of the Zurich Oberland. |
Zürcher E |
Methods for the diagnosis of tree
health and vitality. |
25-42 (1) |
|
The morphological,
physiological, chemical, and physical aspects of ageing in wood, and of
changes in the xylem cell vitality, are presented. The influence of microorganisms
upon these processes is outlined. Methods of ascertaining tree health and
vitality as related to the current forest decline are described. In conclusion,
extended applications of the established procedures and equipments as well
as promising new methods in this field are reviewed. |
Stoll K |
Developments during four decades
of arboriculture in Switzerland. |
43-50 (1) |
|
In Switzerland the
traditional forms of arboriculture with standard fruit trees has been replaced
by intensively managed areas with dwarfing rootstocks. The rising need
for table fruits with long storage abilities has given impulses for growing
new varieties. But oecologistic circles and lovers of old varieties are
angry about this radical change. The traditional standard tree may still
maintain his place for delivering fruits in home use and in the industry
of fruit products. |
Schweizerische
Arbeitsgruppe für Reflexionsseismik |
First Results
of the Traverses Across the Alps of NFP-20 |
61-98 (2) |
|
NFP-20 is a research
program of the Swiss National Science Foundation, with the goal to study
the crustal structure of the alps. Three reflexion seismic traverses across
the alps are supported by 20 additional projects in the field of geoscience.
The eastern and western traverses were recorded in 1986
and 1987, the southern traverse is planned for fall 1988. The data processing
is done internally in the Swiss institutes, the ETH in Zurich and the EPF
in Lausanne.
First results of the eastern and western traverses show
the regular southward plunge of the european crust underneath the alps.
The highly reflective lower crust and the Moho band can be traced to a
depth of 16-17 sec. (48-51 km) below the pennine nappes. There they end
abruptly, to reappear again in the southern portion qf the eastern traverse
at a depth of 15 sec. (45 km). The refraction Moho however is continuous
across.
The external massives appear as upthrusted portions of
variscan upper crust with a detachement surface near the top of the lower
crust.
The pennine front can be traced as a strong band of reflectors,
plunging southward from the Rhone valley to a depth of 5-6 sec. near the
Swiss-Italian border. The sedimentary layers between the Gneis nappes show
up as good reflectors.
The two traverses shot so far, cover only the northern
protion of the alps. The structural features on the southern slope of the
alps, such as the so called root zone and the lvrea body will be studied
this fall in the southern traverse. |
Schluechter C |
New geological observation at
the mammoth site at Niederweningen (canton of Zurich) (Switzerland). |
99-108 (2) |
|
Geological and geotechnical
investigation in the area of the famous Mammuthus primigenius site at Niederweningen
give evidence for a more precise litho- and climatestratigraphic positioning
of the fossiliferous Quaternary beds: these sediments including an underlying
Eemian peat are highly deformed by thermokarst diapirism and by later compaction
faulting. The geocryologically active event is correlated tentatively in
climatestratigraphic terms with the maximum ice extent of the Last Glaciation.
The Niederweningen fauna is older than this event as evidenced by palynostratigraphic
data as well. |
Sauter W, Huber P |
Pharyngomyia picta (Meigen) (Diptera,
Oestridae) as the agent of human ophthalmomyiasis. |
109-113 (2) |
A case of human ophthalmomyiasis
externa caused by Pharyngomyia picta from the Puschlav valley (Grison)
is reported. So far this species was not known as a human parasite, his
genuine host is the red deer (Cervus elaphus). There are only few dates
on the distribution of Ph. picta in Switzerland, all are located in the
canton of Grison. |
Wolters,
G. |
Evolutionary
Epistemology - a Polemic |
125-142
(3) |
|
Evolutionary epistemology
can be viewed as an evolutionary, i.e. not as a "philosophical" but as
a scientific" investigation of our epistemological capability and its achievements.
The presumed, at least partial correspondence between the structure of
our knowledge and the structure of the world is the ma in problem. I argue
in this paper that the evolutionary approach to knowledge is circular and
"metaphysical". This approach, moreover, is inadequate from a conceptual
point of view and represents an obsolete variant of Darwinism that is capable
of "explaining" almost everything in evolutionary terms ("Panglossism").
The anthropological and ethical claims made under the name of "Copernican
revolution" are a new edition of what is in principle an unsuitable and
unacceptable attempt at a scientific grounding ("naturalism") of human
self-understanding. |
Diebold, P. |
The Young Palaeozoic Trough of
Northern Switzerland and its Prospects for Bituminous Coal |
143-174 (3) |
|
The paper reviews
on the basis of data published by Nagra aspects of sedimentation, tectonics
and coal prospects of the Young Palaeozoic Trough of Northern Switzerland.
The sedimentary fill of the Trough consists mainly of
terrestrial fluviatile and lacustrine deposits and has been subdivided
in two parts:
The older part, of Stephanian to Autunian age, seems
to be restricted to the central part of the Trough and comprises e.g. the
coal measures and the Lacustrine-Series, the latter characterised by bituminous
shales. The Lower Alluvial Fan-Series is indicative of synsedimentary tectonics
and placed at the upper boundary of the sequence.
The younger part is reaching unconformably far beyond
the central part of the Trough and comprises the Playa- and the Upper Alluvial
Fan-Series.
The structure of the Young Palaeozoic Trough is dominated
by probably synsedimentary, transpressive tectonic features characterised
by strong lateral variations in relief, folds and over-thrusts. After this
transpressive phase culminating at the boundary between Lower- and Upper
Permian, only weak extensional faulting is suspected for the period of
the Upper Permian.
The coal measures discovered in the well Weiach contain
approx. 60 seams and stringers varying in thickness from 0.1 to 4 m with
a total of approx. 32 m of coal. The coals are limnic, allochthonous and
have a high ash content. They range from subbituminous- to medium volatile
bituminous. The main seam of 4 m is at a depth of approx. 1585 m and has
the following quality: Ash content (Raw coal): 10-18%; Volatile Matter:
31-33%; Calorific value: 28-31 MJ/kg; Sulphur: 0.48% (WAF); Coking property:
positive; Vitrinite reflectivity: 1.01 (R max).
Today no mature technology is available to work the seam.
However, speculative coal prospects exist at a viable depth between 900-1200
m in the overthrust blocks located west of Weiach. |
Hächler,
P. |
Analysis
of the Weather Situations Leading to Severe and Extraordinary Avalanche
Situations |
175-186
(3) |
|
Based on the records
of the Swiss Federal Institute of Snow and Avalanche Research (SFISAR)
some of the most severe and disastrous avalanche situations for about 100
years were selected. Northerly and southerly exposed regions are described
separately. It was found in nearly all cases that a quasi stationary trough
has led to such situations. Frontal developments, led by strong winds towards
the Alps have intensified much the quantities of snowfall, specially at
the windward slopes. The barrage gradients seem to be important, but there
were no extremely high values found. For the recent cases upper air information
is also considered. Usually there was a well defined jet found, indicating
active frontal mechanisms. Finally the possibilities of modern methods
are discussed. It is shown that numerical modeling gives quite reliable
indications for several days. |
Hürlimann J, Schanz F |
Characterization of two connected
ponds with a small catchment area on the basis of plankton biocenoses and
nutrient loadings. |
205-224 (4) |
|
An investigation of
chemical, physical and biological parameters in two connected ponds (catchment
area = 0.7 km-2) in Kusnacht, Canton Zurich, was carried out from February
to October 1987. The most important results, described in sections 3.1-3.5,
are summarized here: 1) both Rumensee and Schubelweiher have a mean depth
of 1.1 m. The mean inflow is 370 m-3/d into Rumensee and 320 m-3/d into
Schubelweiher (mean water residence times: 38 and 52 days respectively).
2) Oxygen conditions were found to be good even when the ponds were iced
over. Oxygen concentrations below 4 mg O-2/l were observed only once during
the summer. 3) Both Rumensee with 66 taxa and Schubelweiher with 95 taxa
were found to possess extremely species-rich plankton biocenoses. Blooms
of Chrysophyceae species suggest nutrient-poor conditions. 4) For each
pond, the phosphorus freight due to the inflows was around 5 kg P/yr and
that due to direct precipitation on to the pond surface was around 1 kg
P/yr (total phosphorus loading: 408 mg P/m-2 cntdot yr in Rumensee; 374
mg P/m-2 cntdot yr in Schubelweiher). According to the nutrient loading
models of R. A. Vollenweider (1976), the phosphorus loading in both ponds
exceeds the critical level of tolerance-this conflicts however with the
biological assessment. 5) The fact that the two ponds are connected results
in the existence of rather better physical, chemical and biological conditions
in the lower-lying Schubelweiher than in Rumensee, which, as the higher
of the two, takes on the function of a nutrient retention basin. |
Bosshardt Hs. Paul |
Developments in agricultural pest
control. |
225-240 (4) |
|
Intensification of
agricultural production has reached limits: further increases would result
in production of surpluses and in environmental contaminations and other
damages to soil and water. This situation requires a more pronounced orientation
of agricultural production towards integrated production, i.e. towards
high quality goods and improved, ecologically sound methods. Plant protection
against pests, diseases and weeds is an important sector. Integrated plant
protection tries to solve this difficult problem by combining a variety
of methods adapted to the annually changing situation: agronomic methods
(crop plant varieties selected according to local conditions, crop rotation),
administrative measures (plant quarantine), use of biological (beneficial
arthropods, fungi, bacteria and virus) and biochemical agents (pheromones),
application of carefully selected chemicals (specifically active, degradable
compounds in appropriate formulations and well aimed applications) and
the use of technical means (traps, weed combs) are combined to an effective,
environmentally sound and socially acceptable system. By this flexible
system, which requires precise observations of nature, the farmer can safeguard
natural productivity and harvest good and sufficient crops. |
Arnold Benz |
Radio Astronomy of the Sun and
the Stars |
241-256 (4) |
|
In the last few years
more and more stars have been found to emit radio waves. Most of these
discoveries are made with the Very Large Array, the most powerful radio
telescope of the world. The experience of the past 40 years of solar radio
astronomy is tapped to interpret the stellar sources. Radio emission mainly
carries information on the outer atmosphere of stars, in particular on
the density, the temperature, the magnetic field and its related very energetic
processes, which widely determine the state of atmospheres. These processes
also occur - with mostly unknown consequences - during the formation of
stars out of the interstellar gas. Young stars are extraordinarily active
and emitters of radio waves. |
1987 132th. |
|
|
Gensler G A |
The climate of Zurich (Switzerland). |
1-18 (1) |
|
Weather systems produce
the variety of instantaneous states of the atmosphere. Climate introduces
the longer time scales and may be regarded as average weather or long-term
state of the atmosphere, including mean values as well as frequencies and
extremes. The urban climate of Zurich and its environment is influenced
by local terrain features, modifying the regional macroclimate within the
temperate westerly wind belt in mid-latitudes. Zurich climate data, mainly
based on the site of the Swiss Meteorological Institute (SMI), show, a
temperate, humid climate with prevailing unsettled weather, especially
in spring and early summer. Relatively pleasant is autumn with its longer
spells of fine weather. Autumn and winter present a gradual increase in
temperature during this century; spring and summer are again at a normal
stage after the remarkable warm and dry period between 1942 and 1953. Due
to local topography the natural ventilation is reduced, causig increased
problems in air pollution. |
Straub M |
Muskrats in the canton of Zurich
(Switzerland). |
19-25 (1) |
|
Musk-rats escaped
from animal-farms for furs begin to behave like indigenous species in several
parts of Europe, so in the canton of Zurich. By digging their holes they
damage engineering works along rivers. For this reason they are controlled
and their further expansion is being prevented by different measures. |
Burga C A |
Geomorphological and pollen analytical
investigations on late- and post-Wuermian deposits in the Grisons (Swiss
Alps). |
26-44 (1) |
|
This study presents
some results of investigations about late- and post-wurm maximum glacier
extensions in the Grisons (Swiss Alps). The last Wurm-maximum glacier extension
terminated before the Oldest Dryas (before 13,000 BP), and the Bolling-interstadial
was characterized by the spreading of Pinus, Betula, Juniperus, and Hippophae.
Until the end of Bolling the Wurm glacier transfluences over the alpine
passes of Lukmainer, Bernhardin, Julier, Maloja, Bernina, La Stretta, and
Viola have been terminated. After the Bolling-interstadial, the alpine
glaciers grew again to the Egesen-stage. During the Allerod-interstadial,
Pinus spread up to 1600 meters above sea level. The climatic depression
of the Younger Dryas lead to a clear diminuation of Pinus and to an increase
in herbaceous plant vegetation cover. Investigations in the Wurm ice-marginal
zones of Feldkirch, Sargans, Chur, and Valtellina allow to model the glacier
melting process since the Wurm-maximum. During the Gschnitz-stage, several
glaciers (Hinterrhein, Landwasser, Inn, Poschiavino, and Adda) existed
independent from each other and, in the Central Alps, the tree line climbed
over 2100 meters above sea level since the early Holocene. The Post-Glacial
can be characterized by the following climatic fluctuations: Palu (Praeboreal),
Oberhalbstein (Boreal), Misox (Older Atlanticum), Piora I/II (Younger Atlanticum),
and Goschenen I/II (Subatlanticum). |
Brunner, W. |
Stone with cup-marks near Wetzwil
(municipality of Herrliberg, ct. of Zurich) |
45-52 (1) |
|
From the stones with
cup-marks, which are today near the Swiss Federal museum, was that of Wetzwil,
Herrliberg, the most remarkable. Astronomical and geographical analysis
shows, that all directions of sunrises and sunsets at the beginning of
the seasons can be found by tangents on the brims of the cup-marks for
the astronomical and the natural horizon (a0... f36 and g-4). Extreme differences
of directions from 42° to 46.5° to east-west by moonrise and moonset
over the 1° elevated natural horizon are marked with cups (h45, i45...
m42. . .and q46.5). In the year 2700 B.C. the North Polar Star was a
Draconis (Thuban) and the meridian t90 could be oriented with it. Later
on in the year 1700 B.C. Thuban oscillated 9° to the north direction.
The extreme deviations were noted by cup-marks fixing r81 and s81. The
stone shows also directions to other stones with cup-marks and cult centres.
It is uncertain if and when all those possibilities were practised. |
Nievergelt B, Anzenberger
G, Stucki B, Zingg R |
Altitudinal zonation of mammals,
birds, and some selected plants on the western slopes of Mount Kenya (Kenya). |
53-64 (1) |
In a reconnaissance
study along the routes to and from Point Lenana characteristic species
of plants and all observed mammals and birds were recorded systematically
in steps of 50 meters. This study was done to enable comparisons with other
afroalpine regions. It was conducted within an ethological and ecological
field ocurse of the Zoological Institute at Zurich University, section
Ethology and Wildlife Research, in northern Kenya. Table 1 shows the altitudinal
zonation of the vegetation and the range of the registered plants including
their flowering phase. The Hagenia-Hypericum-zone was most clearly separated
from the adjoining zones. In a second table the recorded mammals and birds
are listed with their altitudinal ranges. We would like to mention for
the montane belt Black and White Colobus, Bushbuck, Hartlaub's Turaco,
for the alpine belt Rock Hyrax in rocky places, Augur Buzzard, Jackson's
Francolin. Slender-billed Chestnut-wing Starling, Scarlet-tufted Malachite
Sunbird and Tacazze Sunbird were found only in places with flowering lobelias.
Most common and striking animals were the Hunter's Cisticola sbd a duetting
bird species sbd and the Hill Chat. In comparison with corresponding zones
in the more extended alpine ranges of the Simen mountains of Ethiopia,
the species diversity seems to be definitely lower and in the abundances
of some characteristic plant species the wetter climate became apparent. |
Heinloth,
K. |
Are fossil
fuels an alternative to nuclear energy? |
69-87 (2) |
|
As large sources of
energy actually only fossil fuels and nuclear energy are disponible, renewable
energy sources cover - at least in the FR of Germany - just a small amount
of energy demand. In further future solar and fusion power plants are perhaps
disponible as large energy sources. Utilization of fossil fuels and nuclear
energy are connected with high damage risks: Continued utilization of fossil
fuels in actual rates causes an increase of global temperatures by 2 to
4 centigrades by release of carbon dioxide and another 2 to 4 centigrades
by emission of trace gases within the next 100 years. A thus involved climatic
catastrophe would destroy the living space of hundreds of millions of men.
Harm risk of actual utilization of nuclear energy concerns
mainly big nuclear accidents such as Tchernobyl. Those accidents may be
avoided by construction of inherent safe reactors.
The menace of a C02-climatic catastrophe urges a drastic
decrease in utilization of fossil fuel. This in future only may be attained,
if all possibilities of saving energy, of all renewable energy sources
and nucelar energy by inherent safe nuclear power plants are pursued. |
Thierstein,
H. R. |
Paleoceanography:
Global change in the history of the earth |
88-103 (2) |
|
The central question
of oceanographic research is the circulation of the oceans. Paleoceanography,
in turn, is concerned with the history of the oceans and past circulation
changes. As a relatively new, multidisciplinary field it has grown very
rapidly, mostly due to recent developments in oceanography, marine geology,
and micropaleontology. Oceanographic research results have demonstrated
the great influence that oceanic circulation exerts on global environmental
changes in climate, primary productivity, and chemistry of the atmosphere.
Intensive geological exploration of the ocean floors in the last two decades
has revealed that distribution and shape of the world's oceans have been
continuously changing over geological time scales. Recent developments
in micropaleontology hold the promise of improving our understanding of
the causes and timing of these global paleoenvironmental changes. |
Schär,
M. |
Actual situation
in the problem of alcoholism |
104-112
(2) |
|
1. Consumption of
alcoholic beverages increased in Switzerland from 10 liters of pure alcohol
per year and person aged over 15 years to 14 liters in the years 1945 to
1965.
2. Since then the total amount of consumption is stagnant,
but we observe a significnat shifting in distribution
of age of consumers.
3. Were are the main points in fighting against alcoholism
to be put? |
Kyburz,
W. |
Aged, but
not out of date. Geology of Zurich by Alexander Wettstein |
113-117
(2) |
|
One of the most outstanding
geological theses concerning the geology of the aera of Zurich was published
100 years ago. Its main lines are still remarkable and it is well worth
being remembered again |
Britt H |
Lichens as bioindicators of air
pollution, illustrated in an IAP-map of Winterthur (Switzerland). |
123-134 (3) |
|
The following study
presents a contribution to the problem of the air pollution. To get a view
of the air condition it is necessary to measure and map the degree of the
air pollution. The use of bioindicators is particularly apt in this case,
because bioindicators can show the manner the pollutants affect the organisms.
The study especially describes the use of lichens as bioindicators and
a method to map the air pollution following the principles of the "Index
of Atmospheric Purity" (IAP). |
Schluechter C, Maisch
M, Suter J, Fitze P, Keller W A, Burga C A, Wynistorf E |
The profile of foliated peat at
Gossau (canton of Zurich) (Switzerland), and its stratigraphic position
within the last glaciation. |
135-174 (3) |
The reference section
at the Gossau gravel pit has been re-investigated by a multidisciplinary
approach and the bearing of its stratigraphy as well as of the geochronology
on the evolution of the landscape is evaluated. The compressed peat beds
represent the time span from 54,000 to 28,000 y BP and consist of several
overbank depositional cycles of different magnitude without glacigenic
influence. Only after 28,000 y BP a glacial advance occurred, passing the
Gossau area. This advance is not just an important oscillation only, but
represents an independent advance from the Alpine Border to the Foreland.
The palynostratigraphy of the beds between the delta-complex (bottom) and
the most recent flavioglacial/glacigenic accumulative cycle (top) reveals
several oscillations of stadial/interstadial type of vegetation. Below
the Upper Peat Bed a subaerial pedogenesis is detected. |
Kyburz W. |
The weather of Zurich 1986 |
175-181 (3) |
|
The main climatological
dates of meteorological and rain-gauge-stations in the aera of Zurich are
compiled and commented. |
Caratsch C G |
The importance of peripherally
acting neurotoxins for the investigation of neurophysiological processes. |
191-258 (4) |
|
This essay is divided
into two parts. The first part contains a survey of the peripherally acting
neurotoxins (NT) and a characterization of their effects. According to
their specific activity the NT are classified in three groups: (1) presynaptically
acting NT, (II) postsynaptically acting NT - two groups which take effect
mainly on neuromuscular junctions - and (III) NT with an effect on ionic
channels, especially on the sodium channel of excitable membranes. The
second part is a report on studies of my own in order to analyze the mechanism
of action of beta-Bungarotoxin (beta-Bu Tx), a presynaptically acting snake
neurotoxin. The complex action of beta-Bu Tx was studied in detail with
immunological and particularly electrophysiological techniques. |
1986 131th. |
|
|
Schaub,
M. C. |
Mobility
and life |
1-32
(1) |
|
Mobility and motility
represent a basic requirement for life. Cellular sequestration by membranes
against the environment is a prerequisite for life involving metabolism
and self-reproduction. It is dependent on movement of the entire organism
as well as for intracellular transport. The function of movement of flagella
and cilia at the cell surface as well as intracellular amoeboid movement
by the contractile proteins myosin and actin, its regulation by calcium
ions and the necessary energy production are discussed in connection with
the evolution from prokaryotes up to fungi, plants and animals. Formation
and specialization of muscle tissues only occurs in the animal kingdom. |
Schacher,
J., Wyler, D. |
Intermediale
vector bosons W and Z: their significance for particle physics |
33-51 (1)
|
|
The intermediate vector
bosons W and Z were found experimentally in 1983 at the European Centre
for Particle Physics, CERN. In this essay we first describe the theoretical
developments leading to the predictions of these particles and their importance
for the understanding of the fundamental forces. Then we sketch the experimental
aspects and show why they could be observed only recently. |
Ribi Georg, Arter H |
Colonization of Lake Zurich (Switzerland)
by the prosobranch snail, Potamopyrgus jenkinsi, between 1980 and 1984. |
52-57 (1) |
|
The fresh water prosobranch
snail Potamopyrgus jenkinsi colonized most of the Lake Zurich (total length
40 km) within a period of a few years after it became established in the
lake. In 1982 local population densities surpassed 100,000 individuals
per square meter. In 1983 the density dropped by at least two orders of
magnitude and was still low in 1984. |
Wyler R, Engels M,
Metzler A E |
Bovine infectious rhinotracheitis
virus. |
73-91 (2) |
Bovine Herpesvirus
1 (BHV-1) is the causative virus of infectious bovine rhinotracheitis (IBR)
and of infectious pustular vulvovaginitis (IPV). In the present paper it
is shown that by means of restriction patterns and mapping of restriction
sites of the DNA, BHV-1 strains can be grouped into three types. Type 3
was isolated from tissues of calves with nonpurulent meningo-encephalitis.
Cross-hybridization revealed a close antigenic relationship between the
three types. It may therefore be assumed that the three types are differentiated
from each other only by short regions of the genomes. Additionally the
immunogenic components of BHV-1 are dealt with. By means of radioactive
labelling of viral proteins during replication in cells with subsequent
separation of proteins using electrophoresis in polyacrylamide slab gels
and by means of monoclonal antibodies it could be demonstrated that two
complexes of glycosylated viral proteins jointly were responsible for a
humoral immune response by inducing neutralizing and cytotoxic antibodies. |
Glaser,
D. |
Gustatory
Research in Primates |
92-110 (2) |
|
The
function of the gustatory sense organ and the importance upon the quality
of life are mentioned. The efficiency of this organ is discussed within
the order of primates. When comparing both, behavioural and electrophysiological
methods, it appears that those compounds that elicited unequivocal behavioural
reactions (either preference or rejection) produced identical results with
both methods. Special effects in phenylthiocarbamide (PTC), some sweeteners,
proteins and 'taste modifiers' were studied. Furthermore videotaped behaviour
reaction patterns were analyzed. Finally, in accordance with the findings
that are presented here, the sphere - a possible model for the relationship
of gustatory qualities - is presented. |
Waldmeier,
M. |
The Corona
at the Total Eclipse of the Sun on July 31, 1981 |
111-118
(2) |
|
The eclipse was observed
under ideal conditions near Bratsk (Siberia). By a camera of 50 cm focal
length 16 pictures were obtained during the totality which lasted for 84
seconds. They were used for the study of the light distribution and the
structure of the corona. It was a repetition of a programme that was carried
out at earlier eclipses with a view to study the coronas variation during
the activity cycle of the sun. The eclipse took place 1½ years after
the sunspot maximum. Accordingly the streamers were straight and radial
(Fig. 4) as it is the case in a maximum corona. On the other side the isophotes
show a strong flattening (Fig. 7), typical for a minimum corona. Incidentally
the temperature of the air was recorded during the eclipse. The minimum
of the temperature was reached 14 minutes after totality and was 70 lower
than the temperature to be expected without the eclipse (Fig. 1). |
Schmid P |
More finds: More knowledge? The
history of recoveries and interpretation of human evolution. |
145-160 (3) |
|
One of the major developments
in the past 100 years has been the recovery of a substantial number of
hominid fossils all over the world. A general view of the main events in
the history of the finds is given. The discussion of gracile australopithecines
demonstrates that the improved knowledge of human evolution required the
acquisition of different classes of information. Hypothesis of narrative
and mechanism can be formulated based only on findings in comparative biology.
The fossils, the "hard evidence", serve to test these hypothesis. The fossil
record only build up the "quantity" of possible tests. The growing amount
of knowledge in comparative primatology in connection with historical information
causes the change of "quality" in phylogenetical interpretations. |
Buchmueller K S |
Characteristics of annual rings
and vessel lengths of Fagus sylvatica. |
161-182 (3) |
|
Characteristics of
annual rings and vessel lengths determine the hydraulic architecture of
wood, which is of importance for physiology, pathology and technology.
The characteristic of annual rings deals with the dimension, shape and
frequency of vessels, and also with the proportion and the arrangement
of vessel tissue in the transverse section of growth rings. Vessels are
conducting units of the xylem of a finite number of individual vessel elements
arranged end to end; measurement of vessel length supply new information
on the indigenous deciduous trees. Observation of annual ring features
shows that broad rings exhibit fewer but wider vessels than narrow ones.
The actual proportion of vessel tissue varies little with ring width, although
it tends to be somewhat greater in narrow rings. The maximum vessel length
was nearly 88 cm. Vessels with broad lumina tended to be longer than those
with narrow lumina. |
Wildi O |
New methods in vegetation mapping. |
183-189 (3) |
|
Vegetation mapping
is aimed to reveal states and processes in space and time. It relies on
plant-ecological bases, which are a matter of scientific search. With regard
to our rapidly changing environment, the topic becomes rather acute. Results
have to be immediatley available, as detailed as possible and relevant
for wide areas. In order to solve this problem of optimization, three approaches
are presented: Specialized maps, simulation of maps based on external information
related to space, and statistical sampling. While environmental changes
in the past have sometimes been recognized too late, an efficient control
of the vegetation is becoming operational using the new tools. |
Meier, C.A. |
Die Wildnis
und die Suche nach der Seele des heutigen Menschen |
191-203 (4)
|
Huber, G. |
Wissenschaft
und Ethos |
229-233 (4)
|
Zürcher E R |
Stem ontogeny of wych elm (Ulmus
glabra Huds.) under normal and long day conditions. |
235-294 (4) |
|
Subject of this thesis
is the development and structure of the secondary stem xylem of wych elm
(Ulmus glabra Huds.) in relation to formation and structure of the terminal
shoot. Observations were carried out on plants one and three years old,
growing under long day (greenhouse) and normal (nursery bed)conditions.
Both longitudinal and radial growth exhibit periodicity which is the more
apparent the longer primary growth is in progress. In the case of longitudinal
growth, the length of internodes are a direct parameter of the varying
degrees of shoot elongation. The first phase of longitudinal growth is
the formation of that part of the shoot that has been preformed in the
winter bud. During the subsequent phase additional growth occurs which
may show a depression during summer. Plants growing under greenhouse conditions
show longer internodes and thinner stems than those growing under normal
conditions. The "basipetal gradient of xylem formation" is thus more pronounced
in the former. Unlike in adult elms, in juvenile ones the innermost ring
of early wood pores is differentiated simultaneously with the resumption
of apical growth, and it is connected with the preformed part of the new
shoot. Within one growth ring the conducting elements show variation with
reference to dimension and arrangement. Early wood pores are significantly
wider in greenhouse plants than in normal plants. After completion of longitudinal
growth, late wood vessels are formed in a typical banded (ulmiform) arrangement.
In plants growing under normal conditions this formation occurs already
after the growth depression in summer. |
Krause W |
An attempt to determine subfossil
oospores of Charophyta from Swiss lake deposits. |
295-313 (4) |
|
This paper deals with
the possibility to determine oospores of Charophytes from prealpine lake
sediments, which was thought to be impossible up to now. The remainders
are well preserved and therefore can be compared with specimens of recent
species. Difficulties arise from the vagueness of specific characters and
from the broad intraspecific variability within the large genus Chara.
The main problem for the investigator is to bring aberrant oospores (Fig.
3) in relation to typical ones (Fig. 2). The genera Nitella, Tolypella,
Nitellopsis, and Lychnothamnus are rather uniform in shape of their oospores.
In spite of the difficulties, determination is largely possible by comparison
of the unknown oospores with reliably defined recent ones. To master the
enormous number of oospores in subfossil material, the binocular microscope
is the most suitable instrument. Figs. 6 and 7 show oospores from neolithic
lake dwellings, Fig. 7/4 demonstrates a plant which was not yet found in
the prealpine region. |
1985 130th. |
|
|
Rasche,G. |
Das physikalische
Werk Peter Debye's.
no abstract; german only |
1-17 (1) |
Busch,G. |
Peter Debye
(1884 -1966). Werden und Wirken eines grossen Naturforschers.
no abstract; german only |
19-33 (1) |
Kucera,Ladislav.J. |
The morphology of the intercellular
spaces in the wood rays: 1. Present stand of our knowledge on the intercellular
spaces. |
35-74 (1) |
|
A literature review
is presented summarizing our knowledge on the nomenclature and typology,
ontogeny, systematic and histologic distribution, shap and size, constitution,
functions and importance of the intercellular spaces in plant tissues. |
Fritzsche Robert |
The influence of optimal and defective
nutrition of crops on quality of the products. |
75-91 (1) |
|
The available supply
of necessary minerals from the soil for crops, and their relation to one
another, has decisive effects on the quality of the products. Optimal supply
of N is critical. The oft-cited statement that farmers increase their yields
with high N doses without affecting the quality is simply not true, since
the maximum yield for crops is quickly reached with increasing N dosage
but declines significantly above a defined optimum. Clear reductions in
quality occur, together with increasing predisposition to fungal infection.
Despite well developed soil analysis systems, it is still difficult to
define the soil's available supply of individual minerals; this is especially
true of N with the many indistinguishable and changing processes in the
soil. The results of soil analysis must be accompanied by observations
on the crops, especially regarding early developing disorder symptoms,
and continuously improved by further research work. Above all, ionic exchange
competition must be taken into consideration. Many nutritional disorders,
especially in perennial plants, are not caused primarily by unharmonic
absorption of nutrient, but by metabolic disorders. In such cases, allowance
must be made for equilibration between the vegetative and the generative
phases of plant growth, that means between the different organs and metabolic
processes in the formation of the plant, for example the treetop, to eliminate
disorders arising from opposing processes. For this, the specific influence
on metabolic processes by the different growth promoters, such as auxin,
GA and growth inhibitors such as ethylene, must be considered. In recent
years, agriculture benefited from the basic research work of the Federal
Institutes of Technology and the Research Stations on nutritional requirements
of cultivated plants, with clear effects on the improvement of quality
and texture of the products. |
Hantke René |
Relief development and climatic
history of the central and eastern Swiss Alps: 1. Middle Oligocene to early
Miocene. |
92-114 (1) |
|
The history of valley
formation and climatic variation result from combined studies of tectonics,
gravel and heavy mineral contents, stratigraphy and paleoecology of Molasse
fans and fission track datings of igneous rocks. Orogenic uplifts caused
changes in Alpine drainage pattern, but main valley excavations were produced
by early glacier advances during cool phases. Relict reliefs still exist
on the former continental divide. The early-middle Oligocene Altdorf fan
had 2 sources: the western Middle Grisons and the valleys of the Brenno
della Greina river. In late Oligocene, after the Gotthard massif uplift,
these valleys had become tributaries of the Ticino river. The Molasse fans
were formed by release of lakes dammed by landslides or mudflows. The Rigi-Rossberg
fans had their sources in the Schams, Rheinwald and Avers valleys. The
succeeding Hohronen fan was built during the latest-Oligocene climatic
deterioration. Uplift also increased glacial activity, which widened the
valley-heads from the Sursess back to the Bergell and Bernina mountains,
so that ice flowed through the Septimer and Julier passes to Tiefencastel.
Its meltwaters initiated the Schin gorge and formed a connection with the
Posterior Rhine. The Speer fan, corresponding to the lower Rigi deposits,
originated in the Sursess and Arosa area, and the early Miocene Pfingstboden-Kronberg
fan added the Prattigau valley to its source area. The Gaebris fan was
built up by an early Ill river: the younger Sommersberg and Pfander fans
were derived from the Flysch mountains of the Faneren and Vorarlberg by
the Lutz, Frutzbach and Bregenzer Ach rivers. |
Burckhardt,Johann
Jakob |
Paul Nigglis
Verdienste um die Herausgabe des Buches "Die Bewegungsgruppen der Kristallographie".
Note; no abstract, German only |
115-117.
(1) |
Gansser,Augusto. |
The cup-stones
of the Kinabalu
a contribution to the world-wide
distribution of cup-stones |
121-143.
(2) |
|
Prehistoric cup like
depressions, cut into the surface of rocks, are cultural objects which
occur world-wide in the same way, form ans layout. Well known from the
alpine areas, here mostly in connection with other petroglyphs of various
significances, they have also been observed in very remote regions, such
as little known examples from Himalaya, the Easter-Island, Australia and
in particular from the summit region of the Kinabalu in northern Borneo,
illustrate. The cup-stones of the Kinabalu, actually one of the best occurrences,
seem to be related to the death cult of this peculiar mountain. |
Hantke,R. |
Relief development
and climatic history of the Central and Eastern Swiss Alps.
Part 2: Middle Miocene to early
Pleistocene |
144-156.
(2). |
|
Subsidence,
infilling and climatically controlled sea-level fluctuations caused again
a flooding of the Swiss Plain by a shallow sea in the middle Miocene. The
initial uplift of the Aar massif interrupted drainage through the Panix
- Bisistal channel and reversed the flow direction: Anterior and Posterior
Rhines flowed to Chur and Sargans, capturing the Plessur and Landquart
rivers. The united Grisons Rhine built up the Hoernli fan to a much larger
size than its Oligocene individual predecessors. At the emplacement of
Helvetic and Austroalpine nappes, the drainage of the Grisons Rhine river
followed the fault zone of the Alpine Rhine valley towards the newly formed
Lake Constance and to the Danube. Later, the Rhine was diverted towards
the Burgund Gate. In the early Pleistocene, it changed its direction into
the Upper Rhine Plain. |
Kucera L J |
The morphology of the intercellular
spaces in the wood rays: 2. Studies with the scanning electron microscope. |
157-198 (2) |
|
Wood rays of Fagus
sylvatica L., Quercus robur L. and Q. petraea Ehrh were examined by scanning
electron microscopy (SEM), quantitative tissue analysis and the optical
shuttle method. Special attention is given to splitting as a method of
preparation for SEM studies. Triangular and rectangular intercellular spaces
were observed and grouped into 4 categories according to their course.
Pitting, perforations, sculpturing and contents of the intercellular spaces
are described. The occurrence in the Fagaceae of ray sections with and
without intercellular spaces is a useful criterion for ray classification. |
Wysling,Hans |
Gedenkblatt
für Chlyjogg (1716-1785).
No abstract |
213-227,
(3) |
Hünermann,K.A. |
Pleistocene
Mammals of the Canton Zurich. |
229-250,
(3) |
|
A synopsis of the
pleistocene mammals from the Canton Zurich is given in chronological sequence
with detailed comments. |
Kucera,L.J. |
The morphology
of the intercellular spaces in the wood rays: Part 3: Histological Analysis |
251-310
(3) |
|
Shape, size and distribution
of intercellular spaces are statistically analysed. Beech is shown to differ
from the two oak species; however, the results for the two oak species
are identical. The parameters of the intercellular spaces are strongly
correlated with those of the adjacent ray cells. In the Fagaceae broad
rays consist of outer areas with intercellular spaces and inner areas where
intercellular spaces do not occur. Certain relationships between the intercellular
spaces and their position within the growth ring or the trunk radius arise
from the process of ray ontogeny. |
Zürcher,E.,
Kucera,L. & Bosshard,H.H. |
Bildung
und Morphologie der Thyllen: Eine Literaturübersicht.
No abstract |
311-333
(3) |
Cogoli,A. |
Weltraumbiologie:
Das Verhalten der Zellen in Mikrogravität.
No abstract |
334-336
(3) |
Hitzig,W.H. |
Prof.Gian
Töndury zum Gedächtnis. |
343 (3) |
Ziegler,E. |
Biochemical
influences of the excess in refined carbohydrates on the development and
function of the brain - hypothesis or fact?
abstract and title |
345-373
(4) |
|
In "western food"
the excess in sugar and the other refined carbohydrates influences the
neuronal and hormonal regulation of the complex biochemical and biological
processes and probably disturbs through disregulations the structural development,
and in children and juveniles, also the function of the brain. Similar
to behaviour teratogens the sugar-excess of the mother probably induces
some early behaviour problems in the child. The excess in sugar of the
grown-up child seems to be the main cause of growth acceleration and of
the procession of physical maturity. Sugar addiction of the accelerated
juveniles of today enhances the puberal problems and causes frequently
through the postprandial centraJ glucopenia the subjective symptoms of
the pseudohypoglycemia, which may also enhance the juvenile delinquency. |
Kucera,L.J. |
On the Morphology
of the Intercellular Spaces in the Wood Rays.
Part 4: Investigations Using Optical
Shuttle Microscopy and General Review |
374-397
(4) |
|
In both beech and
oak, radial intercellular spaces constitute a complex network of cavities,
which in spite of structural differences between the species are of equal
importance for gas exchange. The intercellular spaces in the rays of oak
are shorter but more intensively interconnected than those of beech. The
radical development of the ray areas with intercellular spaces in the xylem
part of the ray is connected with the sclerification processes in the phloem
part of the ray, in terms of both development and function. |
Guyer,E.V. |
Ein Querschnitt
durch die Geschichte der NGZ in losen Folgen. |
398-406
(4) |
1984 129th. |
|
|
Straumann,N. |
Particle physics and the early
universe |
1-20 (1) |
|
Recent developments
in particle physics have important cosmological implications. The violation
of baryon number in grand unified gauge theories has led, for the first
time, to a rational qualitative explanation of the matter-antimatter asymmetry
of the Universe. Other basic cosmological questions appear in a new light.
Of particular importance are the expected phase transitions, which are
associated to the hierarchy of spontaneous symmetry breakdowns of the gauge
symmetry and of other symmetries in the course of the evolution of the
very early Universe. The new theories have also led to speculations about
the existence of exotic matter (massive neutrinos, magnetic monopoles,
photinos, gravitinos, etc.), which might be important for the dynamics
of the Universe and for the origin and composition of Galaxies. |
Fröhlich,E. |
Radiation-induced Cancer: The
methods and the problems of quantitative risk assessment |
21-37 (1) |
|
The quantitative assessment
of radiation-induced cancer risk is a two-step procedure. First, the increase
in cancer incidence in an exposed population has to be determined and its
relation to the measured or estimated radiation dose has to be explored.
Secondly, different mathematical models are used to derive probabilities
for the dose-dependent extra-risk. Risk factors for small and very small
exposure levels are of great consequence owing to the widespread public
concern focused on this issue. This paper reports a summary of the methods
which are a pre-requisite to understand the results of the BEIR III report. |
Burkart,W. |
Genetic risks from ionizing radiation:
yesterday, today, tomorrow |
39-50 (1) |
|
The published results
in the BEIR III-report of the National Academy of Sciences (1980) concerning
the genetic risks to populations exposed to low levels of ionizing radiation
are summarized and commented. The various problems which appear in extrapolating
animal data to humans as well as the uncertainties found in determining
the radiation risk after accidental whole-body exposure lead the subcommittee
to the decision to express the risk values in variation-ranges. The comparison
with the UNSCEAR-reports 1977/1982 suggests that the weight of these estimations
lies in the lower part of this spectrum. The genetic risk is newly defined
as the number of induced effects per generation and rem. A direct estimation
of first-generation expression of damage is described as well as the conventional
method based on the relative mutation risk. The most important results
are summarized in table 1. |
Hutter,K. |
Mathematical prediction of barotropic
and baroclinic processes in the Lake of Zurich and the Lake of Lugano |
51-92 (1) |
|
Some of the current
and thermistor-chain data that was collected in Lake of Zurich and Lake
of Lugano is physically interpreted by means of hydrodynamic models. The
shallow water equations are used to determine the periods and structures
of the surface seiches. The equations are integrated using finite difference
and finite element methods and the Kantorovich technique. The results obtained
with these methods are compared and the advantages of the various methods
are discussed. Then, wind-induced currents of a homogeneous lake are treated
and it is explained why satisfactory prediction of the barotropic motion
in Lake of Zurich requires a three-dimensional circulation model. It turns
out that the non-linear advective terms must be included in the analysis,
if the local transport should qualitatively correctly be predicted. A simple
criterion permits estimation when two-dimensional models are sufficient
and when a three-dimensional model is necessary. Internal seiches are interpreted
by means of two-layer models. Such models exist in various approximations.
These are discussed, and their range of validity is delimited by determining
the periods and structures of the eigenmodes. Finally, baroclinic, wind-induced
currents in Lake of Zurich are discussed. The corresponding FD-model is
delimited with respect to its applicability, and it is shown that it predicts
quite accurately these lake processes which are directly subject to the
wind; the oscillations which set in after the cessation of the wind are,
however, too much attenuated. |
Bosshard,W. |
Die schweizerischen Waldbesitzer
vor der Bedrohung sterbender Wälder. |
93-98 (1) |
|
(note) |
Michel C; Meier M |
Radiation effects on prenatal
development. |
105-123 (1984) |
|
Prenatal development
is characterized by its high radiosensitivity. Therefore, radiation exposure
of an embryo or a fetus is of great concern for human health. Irradiation
during gestation can cause death, growth retardation, malformations, functional
impairment and malignant diseases in childhood. These effects are strongly
related to the developmental stage and the radiation dose. The 1st trimester
is regarded as the period with the highest risk of cancer and malformations.
At present there is considerable agreement, that doses of lt 1 rad would
not have widespread effects on the developing embryo or fetus (BEIR III).
Different commissions on radiological protection recommend to keep exposures
below 1 rad, except when vital indications demand higher doses. The possibility
of interactions between radiation and drugs, stress, diet, genetic and
other factors adds a cautionary element to risk estimations. As consequences,
unnecessary exposures of embryos and fetuses should be avoided and further
information is highly desirable particularly at the low doses of interest
for radiation protection. |
Fritz-Niggli Hedi |
Risks of health damage by ionizing
radiation: Yesterday, today, tomorrow. |
124-141 (2) |
|
The risks of health
damage due to low levels of ionizing radiation are always embedded in the
variation of the natural (spontaneous) rate of damage, in the variation
of radiation exposure and the influence of additional noxes. The average
of the radiation exposure (equivalent dose) for Swiss people is 250 mrem
with a fluctuation from 138-436 mrem. Medical applications of 150 mrem
are responsible for most artificial radiation exposure. Earlier assessments
of possible risks of health damage due to low doses mainly considered the
genetic damage, but nowadays studies of somatic risks are placed in the
foreground. The effect of doses between 0.5-10 rem can only be estimated
by interpolating different dose response functions. It is advisable to
use the linear dose response model for radiation exposure estimates. The
risk estimations for genetic and somatic risk have not changed considerably
for 10 yrs. |
Schneider F |
Geometry and degree of resolution
of an animal receptor of gravitational waves. |
142-171 (2) |
|
After discovery of
magnetic orientation of animals in 1957 additional experiments with cockchafers
(Melolontha vulgaris F.) proved the great influence of terrestrial and
cosmic masses on ultraoptic orientation and activity. This influence has
the character of waves. Today's current meaning of the word gravitational
wave has to be extended. The paper deals with the analysis of an animal
receptor of gravitational waves (graviceptor) based on 72 photographs and
952 azimutal measurements (accuracy +- 0.5 degree ). The experimental results
correspond with a graviceptor model composed of 6 mutually turned octahedrons.
The graviceptor is dipped in the direction of the head. These 2 experiments
prove again the capacity of animals to perceive exactly the directions
of terrestrial and cosmic masses (walls, sun, moon) in spite of exclusion
of any optic, magnetic, electric and electromagnetic information. |
Ørn,Ch .G. |
Development of wind conditions
in the cold season from 1891 to 1982 and its effect on annual hypolimnetic
oxygenation in Lake Zurich |
172-180 (2) |
|
In the sub-alpine
Lake Zurich (A = 65 km2, zMax= 136 m, z mean = 51 m) annual hypolimnetic
reoxygenation begins during autumnal cooling and ends with summer stratification.
A stable winter stagnation rarely occurs, so vernal circulation is normally
found between January and March/beginning of April. Analysis of hourly
wind velocities at the nearby meteorological station SMA Zurich since the
year 1891 proved that wind activity in these months has decreased (fig.
1). Strong winds have become rarer. Previous studies have shown that winds
> 20 km/h (wind velocity 4) are of particular importance for the wind-related
oxygen increase in the hypolimnion of Lake Zurich.
The decrease becomes even more apparent when estimating
the wind energy working on the lake surface. Around the turn of the century
energy sums totalling > 2 MJ/m2 of lake surface were calculated for numerous
years (table 1). Since the beginning of the continuous limnological monitoring
of Lake Zurich in 1936 they have varied from 0.04 MJ/m2 in 1964 - the worst
hypolimnetic oxygen year - to 1.15 MJ m2 in 1970 - the best oxygen year
for a long time. The second worst oxygen year occurred in 1963, when the
lake was completely ice-covered from 24th February to 28th March. Deducting
the winds recorded during the period of ice cover ("ice winds") only 0.03
MJ/m2 of wind energy remained to oxygenate the lake. As in 1964, the hypolimnion
thus entered summer stratification burdened with a serious oxygen deficiency
(table 2). From a limnological point of view the decreasing wind trend
is a negative natural phenomenon. More wind action would favour turbulent
uptake of atmospheric oxygen in the cold season. |
Hotz Bolliger H |
Morphology and behavior of the
hirudinean, Haementeria steineri, new species. |
181-206 (2) |
|
H. steineri sp. nov.,
discovered in Switzerland, was probably imported from the Brazilian Amazon
region. They parasitize aquatic snails and appear to reproduce via parthenogenesis.
The coelomic and circulatory morphologies are compared with those of Helobdella
stagnalis (Glossiphoniinae). The new species is described and the genus
is transferred from the Haemeuteriinae to the Glossiphoniinae. The comparative
structures of the coelom and gut of Piscicolidae and Glossiphoniidae demonstrate
that the latter is more primative. |
Burgen,A.S.V. |
Current aspects of synaptic transmission
in the nervous system. |
207-208 (2) |
Müller,St. |
Deep structure, dynamics and evolution
of the Mediterran-Alpine region |
217-245 (3) |
|
The geodynamic processes
in the Mediterranean-Alpine region are primarily governed by the relative
motion between the African and the Eurasian lithospheric plates. It presently
results in a predominantly compressional regime leading to lithospheric
shortening (of about 5 to 10 mm per year) and rifting in old, pre-conditioned
zones of weakness. The boundary between these two major plates as defined
by the recent seismicity is rather complex: it clearly extends all the
way into the Alps due to the presence of the "Adriatic promontory" of the
African plate. Thus a reasonable explanation is provided for the particular
geographical location of the Alps and their deep structure as the consequence
of a massive continent-continent collision which has led to a "delamination"
of parts of the lithosphere, i.e. in particular "flaking" in the upper
crust, combined with a thickening of the entire crust and the formation
of a pronounced, relatively cold, dense, slowly subsiding "lithospheric
root" beneath the mountain chain. In this still ongoing plate collision
process the lower parts of the lithosphere apparently have penetrated the
upper mantle to a depth of 100 to 200 km in a nearly vertical "zone of
subfluence". On this scale the presently continuing uplift of the Alpine
chain (by 1 to 2 mm per year) is a secondary effect due to isostatic rebound
of less dense crustal masses which previously had been pushed to greater
depths. A configuration of this type generates regionally a dynamics of
its own on which - within a wider framework - rotational processes may
be superimposed. |
Straumann,N. |
White dwarfs, neutrino stars and
black holes |
246-267 (3) |
|
The physics of the
compact final states of stars has made remarkable progress since the discovery
of pulsars in 1967. Because these end products of stellar evolution span
an enormous density range, their analysis requires a deep physical understanding
of the structure of matter and of the nature of interparticle interactions
over a vast range of parameters. All fundamental interactions play an essential
role in the formation, the structure, and the stability of compact objects.
The modifications of the enormous gravitational field strength due to general
relativity become quantitavely important for neutron stars. General relativity
is indispensable for even a qualitative understanding of black holes. Neutron
stars can be observed directly as pulsating radio sources and indirectly
as X-ray sources (X-ray pulsars and X-ray bursters) and more recently as
g-bursters. The opening of the "X-ray window"
led also to the discovery of a black hole in the irregular, rapidly fluctuating
source Cyg X-l. The energy source of quasars and other active galactic
nuclei may involve accretion of matter onto supermassive black holes because
this is the most efficient way to convert rest mass into radiation, and
thus generate in a small volume the enormous luminosities observed from
quasars. |
Säuberli,H. |
Surgical treatment of peptic ulcer |
268-293 (3) |
|
Today vagotomy should
be an integral part of every operation which is done by ulcer disease.
Truncal vagotomy with pyloroplasty is because of its simplicity the preferred
operation in complications (bleeding, perforation). For elective surgery
vagotomy should be only selective, that means limited to the stomach. If
the innervation of the antrum is preserved it is possible to do a proximal
selective vagotomy without pyloroplasty. As a result of recent trials the
result of proximal selective vagotomy (PSV) can now be judged with more
certainty: The rate of recurrence is higher than after partial gastrectomy
or combined procedures, but mortality is low and sequelae are rare. Recurrent
ulcers after PSV usually have a good prognosis. It is not justified today
to do as primary operation the resection or a truncal or a selective gastric
vagotomy because mortality, morbidity as well as sequelae occur in a higher
percentage of cases than in cases of a proximal selective vagotomy without
drainage. |
Gerber,E.K. & Scheidegger,A.E. |
A chronical slide in argillaceous
material |
294-315 (3) |
|
Geomorphological processes
are influenced by three factors: the topography (form), the material involved
and the dynamic conditions. As an example of a geomorphological process,
a chronic slide in argillaceous material in the Jura Mountains in the Canton
of Aargau, Switzerland, has been investigated over a period of 18 years.
It is shown that the properties of the material influence the course of
the slide decisively: because a transition from solid to plastic and thence
to fluid behavior has to take place, the slide occurs intermittently: short
periods of activity alternate with long periods of quiescence. The active
phases are triggered by heavy precipitation in winter combined with melting
of the snow. A correlation-study shows that the precipitation causes motion
at the fissures at the head of the slide after 1 day, in its upper part
after 3-6 days, and at its bottom after 10-12 days. In this fashion, a
complete dynamic model of the process is obtained. |
Speiser,D. |
Leonhard Euler, 1707-1783, Mathematiker
- Physiker - Ingenieur.
German |
325-338 (4) |
Bangerter U M |
The occlusion of longitudinal
wounds on the stem of Larix decidua and Picea abies. |
339-398 (4) |
|
Histology and partly
histochemistry were studied on specimens collected periodically from numerous
simultaneously wounded 4 yr-old stems of larch and spruce. The immediate
phenomena leading to wound occlusion were investigated as well as wound
induced changes within the cambial differentiation pattern in the vicinity
of the wound edge. On the average wound reactions start earlier and are
stronger in Larix than in Picea. An histochemical barrier against pathogenic
infections is effected by excretion of resin and by synthesis of polyphenolic
compounds in parenchyma cells of that portion of the secondary xylem which
is near the wound edges, and has been formed immediately before and after
wounding. On the phloem side of the wound the barrier consists of a wound
periderm which differentiates below a zone of lignified, dying tissue (wound
bark scale). The tissue deficit caused by wounding is compensated gradually
by 2 wound ribs which are formed near the cambial wound edge. These wound
ribs consist of callus produced by the cambium and the wound phellogen.
Cambial regeneration sets in from the edges of the remaining cambium by
means of periclinal cell divisions in the callus. By the end of the growing
season, the products of these divisions differentiate gradually into fusiform
and ray initials. When the 2 wound ribs join there is fusion of the wound
periderms as well as of the edges of the regenerating cambia bordering
the wound. |
Guyer,E.V. |
Ein Querschnitt durch die Geschichte
der NGZ in losen Folgen. |
399-404 (4) |
1983 128th. |
|
|
Fierz,M. |
On the Origin of Wave-Optics |
1-20 (1) |
|
The picture physicists
form of the origin and development of wave-optics contains several misunderstandings.
In some measure they are due to the fact that the difference Newton introduced
between descriptive "theories" and explanatory "hypotheses" was not taken
seriously enough. Further one did not realize that the word "wave" had
not the same meaning for Hooke and Huygens as it has today. In this respect
Newton's sketch of a wave-theory is nearer to the modern view. But just
because of his deeper insight he was baffled by a difficulty to which only
Fresnel found a plausible answer, and only at the end of the 19th century
was the question really cleared up. |
Wildermuth,H. & Krebs,A. |
Man-made Wetlands as Habitats
for Dragonflies |
21-42 (1) |
|
In Switzerland 58
% of the dragonfly species must be considered as endangered or are already
extinct. The main causes for the qualitative and quantitative decline of
the odonate fauna are pollution, change and destruction of the various
larval habitats. Most of the endangered species inhabit natural or nearly
natural biotopes. These dragonflies can only be protected by the conservation
of the still existing remains of intact breeding sites. Investigations
in the Swiss midlands show that odonata using anthropogenic wetlands (gravel
pits, nature conservancy ponds, factory ponds and peat-diggings) for their
propagation seem to have a better chance for survival, because those types
of habitats are permanently reproduced. In gravel pits 39 species (31 certainly
or probably breeding) were observed. Peat-diggings are colonized by 37
species (30 certainly or probably breeding). In garden ponds and nature
conservancy pools 24 species were found (18 certainly or probably breeding),
whereas the numbers in the factory pools is rather poor: 22 species, 8
certainly or probably breeding. The total number of species recorded in
the four types of man-made wetlands was 43. Breeding was confirmed in 27
species and probable in 10.16 out of 43 species (11 certainly or probably
breeding) belong to the category of endangered odonata. The dragonfly coenoses
of the anthropogenic habitats are composed of more or less adaptable species.
Presumably they inhabited the stagnant water bodies of the (now disappeared)
natural stream valleys, bogs, ponds and lake shores. The conservation of
the still existing populations dwelling in manmade habitats is only possible
by protection, increase and suitable management of these sites. |
Philipp,B.J. |
Arnold Heim's unsuccessful oil
exploration and successful water exploration in northeastern Arabia in
1924 |
43-73 (1) |
|
In the mid-twenties
Arabia's rich oil deposits were still undiscovered. In 1924 the then university
lecturer Dr. Arnold Heim (1882-1965) from Zurich, by order of the Eastern
& General Syndicate, London, conducted an expedition with 60 participants,
which served for the exploration of the oil and water resources in the
geologically still little explored areas of Kuwait, al-Hasa (in present-day
Saudi Arabia) and Bahrain in northeastern Arabia. After his two-months
exploration, during which he and his work suffered from the summer climate
of the Persian-Arabian Gulf region, he was convinced of the failure of
future oil drilling, but of the success of future water drilling at some
places in those areas. The results of his voluntary water exploration in
Bahrain were exploited before long with great practical benefits. A second
geological exploration in Arabia, which he aspired to during the following
decade, did not materialize, and the Arabian journey undertaken in 1924
quickly fell into oblivion, although Heim took advantage of part of his
research material by means of several magazine articles and lantern-slide
lectures. |
Schütz,J.P. |
Emanations délétères,
précipitations acides et dépérissement de forêts.
(french only, summary of a symposium) |
75-79 (1) |
Tittmar H G |
Gravity as a Zeitgeber: The mechanism. |
81-88 (2) |
|
Gravity is not only
a physical vector providing organisms with a spatial reference frame, but
it may also be utilized to provide a temporal reference frame, thereby
acting as a synchronizer. The mechanism inherent in this is traced to the
Arousal I system of Routtenberg's Two Arousal Hypothesis. There may be
no single center for the biological clock and sensing may not be continuous. |
Klingler,J., Güntzel,0.
& Kunz,W. |
Xiphinema and Longidorus Species
(Nematoda) on the Swiss Plateau. |
89-114 (2) |
The distribution of
the species of these genera was investigated systematically in vineyards
and in apple orchards and sporadically in some other crops (e.g. strawberries).
Three species of the genus Xiphinema were found: X. diversicaudatum, X.
vuittenezi and X. index. (A fourth species, X. pachtaicum. originates from
the Valais.) Of the genus Longidorus the species L. elongatus, L. macrosoma,
L. profundorum, L. caespiticola and L. leptocephalus are present. Moreover
there are two further species, resembling L. goodeyi and L. elongatus respectively.
The localities of the finds of all the species are given in fig. 4-6. X.
diversicaudatum shows a striking geographical distribution pattern: it
is lacking in Eastern Switzerland and in the adjacent South German area
(fig. 7), but occurs west of the basin of Walensee and Zu"nchsee and of
the Limmat valley. The boundary line of distribution corresponds about
to the line of touching between the Linth and the Reuss glacier during
the time of maximum glaciation.
L. profundorum preferably occurs in the fallow strips
of modern apple orchards, which refers to a possible phytopathological
significance. X. diversicaudatum, X. index and L. macrosoma were associated
in several cases with the occurrence of NEPO-viruses on host plants. The
relatively frequent finds of X. diversicaudatum, L. elongatus and L. macrosoma
mainly occurred in sandy loam and somewhat less often in loam soil; the
latter two species sporadically also in lighter and in heavier soils. L.
profundorum prefers loam soil. The soils in which X. diversicaudatum were
found were acid or neutral, those in which L. macrosoma and L. profundorum
occurred, were clearly alkaline - apart from some exceptions. |
Lienhard,Ch. |
The Psocids from the Region of
Zurich, Switzerland (Insecta: Psocoptera). |
115-129 (2) |
|
Psocids predominantly
belong to the fauna of forests, where they are inhabiting trees, shrubs
and sometimes leaf litter. Several species are frequently found indoors
and associated with human habitations. Psocids are generally feeding on
microflora growing at these places. At present 60 species are known from
the canton of Zurich, especially from the surroundings of the city of Zurich.
For every species some information is given on its habitat preferences,
phenology and abundance in this region. There are also made some general
remarks on faunistics, phenology and ecology of these insects in this area.
Densities of psocids (number of species and density of individuals) on
different plant species and merotopes (e.g. living or dead branches) are
remarkably similar. Beyond the often very clear preference for conifers
or deciduous trees quite a number of species prefer also a particular merotope.
Specializations in individual plant species are usually much less evident. |
Schlatter ,R. |
The Liassic ammonites described
by Karl Mayer-Eymar (1826-1907). |
131-134 (2) |
|
In an issue of diverse
works, published in the years 1864-1875, Karl Mayer-Eymar described a number
of badly known or completely new Jurassic ammonites. The systematics of
the Liassic ammonites, listed therein, are treated in this paper. Under
the new species described by K. Mayer-Eymar, Paracoroniceras militaris
has to be emphasized. |
Jost,R. |
Walter Heitler (1904-1981). |
139-141 (2) |
Jost,R. |
The Nature of Matter and Force:
Emil du Bois-Reymonds World Model. |
145-165 (3) |
|
Emil du Bois-Reymonds
materialistic-mechanistic world view and his rejection of the German romantic
"Naturphilosophie" are analyzed. A sketch of the development of Field-Theory
starting with M. Faraday is given. |
Lüscher ,H .R. |
Self-organization as an ordering
principle in the central nervous system |
167-180 (3) |
|
Despite the fact that
the reductive approach in neurobiological research has led to spectacular
discoveries, more and more scientists believe that the orderly function
of the brain cannot be satisfactorily understood from the analysis of its
buildingblocks alone and their mutual interactions. In this paper an attempt
is made to explain the highly ordered functioning of the brain as being
due to a self-organizing process, the roots of which are found in the collective
behaviour of large populations of nerve cells. In a first example a hypothesis
is presented concerning the rhythmogenesis of respiration. By means of
the Lotka-Volterra model the collective behaviour of a group of neurons
making up the respiratory centers is described. In a second example it
is proposed that the "size principle" of motoneuron recruitment is due
to a self-organizing process during development of the connectivity between
sensory nerve cells and motoneurons. This example illustrates how a probabilistic
mechanism on the level of the single cell can lead to a deterministic behaviour
of a large group of neurons. |
Stranzinger,G. |
Genetic engineering in animal
breeding - present state and research. |
181-194 (3) |
|
The article describes
from different views the use of gene technology in animal breeding and
genetics. Reasons for the use of gene technology in combination with genetic
engineering in animal breeding are documented, with special attention given
to aspects of world nutrition and the use of genetic peculiarities and
resources. The mechanical complexity of the problem of the genetic manipulation
of mammalian cells is visualized through selected examples which compare
the genome size for viruses, bacteria and mammalian cells to each other.
A description of natural and artificially produced chimeras in cattle,
the development and existence of these animals and the biological consequences
of chimerism give us a better understanding of the interference between
gene transfer and other micromanipulation techniques. The exemplatory description
of the gene transfer method should help to elucidate several mentioned
general research activities in animal breeding, which can be seen as preliminary
to the application of further advanced techniques. |
Schanz, F. & Thomas
E A |
The Walenseeli, a small lake near
Baech (Canton Schwyz (Switzerland)) connected with Lake Zurich. |
195-205 (3) |
|
The Walenseeli is
a small lake of glacial origin, connected by a channel 3 m deep and 50
m broad to Lake Zurich. The western part of the lake is 14.3 m deep; the
eastern part is shallow. As a result of the lake's small surface area (0.104
km2) and of the fact that it is protected from wind by surrounding
hills, the surface water warms up faster; thus a stable stratification
forms earlier than in the adjoining Lake Zurich. The seasonal variations
in O2, nitrate and phosphate concentrations in the surface water
clearly show that the spring plankton bloom develops more intensely in
the Walenseeli than in Lake Zurich. Hypolimnetic O2 conditions
also point to the Walenseeli being more highly eutrophic than Lake Zurich:
the hypolimnion of the Walenseeli is completely anaerobic at the end of
the summer stagnation period, in contrast to Lake Zurich, where even directly
over the sediments high O2 concentrations are found during the
whole year. As a result the sediments of Lake Zurich are light gray in
color; those of the Walenseeli are gray-black. No evidence of any influence
of Lake Zurich on the Walenseeli can be found. The Walenseeli can be considered
as a lake in its own right, independent of lake Zurich. |
Pavoni, N. |
Earthquakes and global tectonics. |
213-231 (4) |
|
The belt of young
fold mountains and the belt of active oceanic ridges represent the major
tectonically active systems of the earth. They are clearly outlined by
the distribution of earthquakes. Specialized seismological investigations
give valuable information about the type and orientation of earthquake
generating fault movements and therewith about the present state of deformation
and stress in the crust and lithosphere of seismically active areas. In
many regions of the Cenozoic fold mountain belt Switzerland included the
present tectonic movements are in close relation or even direct continuation
of neotectonic movements. They are part of large-scale continuous tectonic
processes. Emphasis is given to a Pacific - anti-Pacific hemispherical
symmetry in global tectonics which is apparent in the geotectonic evolution
of the African and Pacific hemispheres during last 150 million years. |
van der Waerden,B.L. |
Models of dose-effect curves after
irradiation |
233-242 (4) |
|
For the evaluation
of the risks of radiation damage it is important to know how the damage
depends on the dosis. Three possibilities are considered: a linear function
a pure quadratic function and a mixed "linear-quadratic" function. In the
present paper a sequence of experiments on Drosophila are analyzed. The
flies were exposed to small middle and large doses of radiation and mutations
in the first generation were observed. A statistical analysis yielded the
following results: 1. The most frequently observed mutations were caused
by the loss of an X- or Y-chromosome. in these cases the results can very
well be described by a linear function of the dosis. The deviations from
the linear function are statistically insignificant. 2. Two kinds of partial
chromosome loss were observed. In one of these cases a pure quadratic or
linear-quadratic function could be appropriate. 3. In all other cases the
number of mutations is too small to draw valid conclusions. The safest
assumption is always a linear function. In all cases in which the mechanism
of the damage is unknown one should assume a linear function. |
Neuenschwander,E. |
René Descartes and the
Development of Modern Mathematics |
243-281 (4) |
|
The present paper
traces the development of modern mathematics from the end of the Middle
Ages to the time of Leibniz and Newton. Part I begins by identifying a
number of factors which played a decisive role in the emergence of the
"New Science" and then goes on to present a brief survey of the main areas
of mathematical research in the 16th and 17th centuries. Part 2 provides
a more detailed examination of the development of algebra from the Greek
"geometrical algebra" to the "symbolic algebra" of Viète and Descartes:
it also investigates the transmission of knowledge between the various
cultural eras and the first algebraic solution of third degree equations
in Italy. Part 3 describes the creation of the calculus. In particular,
the successive elaboration of methods of integration in the 16th and 17th
centuries is illustrated by examples drawn from the works of Kepler, Cavalieri,
Wallis, Fermat and Newton, and details are given of the Cavalieri principle,
the various methods of differentiation in use at the time. and the dispute
over priority claims between Leibniz and Newton. The paper ends with a
brief consideration of Descartes contribution to these developments. and
of the calculisation of mathematics during this period. |
Fritz-Niggli, Hedi |
Die Wirkung kleiner Dosen ionisierender
Strahlen auf die Bevölkerung. |
283 (4) |
Thomas, E.A. |
Edwin Messikommer (1891-1983). |
285-287 (4) |
1982 127th. |
|
|
Max Waldmeier |
Observation of the Total Eclipse
of the Sun on February 16, 1980 |
1:1-18 |
|
The eclipse was observed
under ideal conditions at Yellapur (India). Two cameras were used, one
of 50 cm focal length, the other one of 120 cm. During the totality 34
pictures were obtained for the study of the light distribution and the
structure of the corona. The eclipse took place almost exactly at the time
of the maximum of the solar activity. The same programme was carried out
at the eclipse of October 23, 1976 which coincided with the minimum of
the solar activity (Fig. 2). These two eclipses yield the material for
a comparative study of the extreme forms of the corona (Fig. 4, 5, 7 and
11). At maximum the corona is twice as bright as at minimum and its isophotes
are almost circular (Fig. 3). The different behaviour of the two hemispheres
results from a phase shift, the development of the northern corona being
ahead of that of the southern one by several months (Fig. 4, 6, 9 and 11).
The streamers are nearly rectilinear but in general they deviate from the
radial direction. These inclinations are of a systematic character, being
strongest at the equator and the poles (Fig. 13). |
Hansruedi Wildermuth, René
Hantke und Jacques Burnand |
The Drumlin Landscape of the Zurich
Oberland |
1:19-28 |
|
The purpose of the
annual excursion 1981 of the Society of Natural Sciences of Zurich was
to look at the drumlin scenery near Wetzikon (BLN-Object 14.01) and the
gravel-pit of Langfur-Gossau. In addition to the remarks given by the different
guides in charge this report shows the geological and biological importance
of this region and the reasons why it should come under protection. |
Hans Heinrich Bosshard, Ladislav
J. Kucera und Ursula Stocker |
The Vessel System in the Prejuvenile
Wood of Ash |
1: 29-48 |
|
The vessel system
of ash (Fraxinus excelsior L.) is known to display a ring-porous arrangement
in the juvenile and adult wood. In the prejuvenile phase, this typical
pattern is not developed: Pores do not differ much in size nor are they
ordered in closed tangential rows along the growth-ring boundary.
In our three-dimensional investigations of the material
we have measured a larger radial displacement of single vessels as compared
with beech (Fagus silvatica L.). In this latter species the tangential
displacement dominates. In oak (Quercus robur L.) we have found an accordance
with ash.
This tendency of a radial displacement of the vessels
in the ring-porous species is even more pronounced through the presence
of growth-ring bridges.
As it has been shown by K. Ladefoged (1952) the cambial
activity in ring-porous species starts earlier than the bud-break, in diffuse
porous species later. Considering the special arrangement of the pores
in prejuvenile wood we may state that the ring-porous pattern is not only
a topographic fact but even more strongly one dependent on time. |
Manfred Hesse |
Chemistry in the Age of Enlightenment |
1: 49-70 |
|
After a short survey
of the history of chemistry the author discusses how the development of
the combustion theory in the 17th and 18th centuries changed chemistry
from being dependent on other sciences to becoming a scientific discipline
in its own right. Particular attention is paid to the phlogiston theory
of Becher and Stahl and how it was disproved by Scheele, Priestley, Cavendish
and especially Lavoisier. Modern chemistry was created in the Age of Enlightenment.
Alchemistic tendencies which continued parallel to the scientific ones
at that time are briefly mentioned at the end of the paper. |
Bosshard, H.H. |
... Hr. Doctor juris Göthe von Frankfurt |
1:71-78 |
Rieber, H. |
Das Paläontologische Institut und Museum der Universität |
1:79-80 |
Thomas, E.A. |
Die hydrobiologisch-limnologische Station der Universität |
1:81-83 |
Ernst Ott |
Morphological and Physiological Ageing of Secondary Phloem
in Larix decidua Mill. |
2: 89-166 |
|
The secondary phloem
of young European larch was investigated microscopically and histochemically.
Shortly after the loss of their functioning capability, the sieve cells
collapse whereby the sieve areas and the thickness of the cell walls do
not change actively. Their percentage area in the tissue is reduced from
70 to 8% within three years through subsidence of the tangential walls
and the folding of the radial walls. The axial and ray parenchyma cells
increase their percentage in the tissue from 21 to 64% by growing and rounding
off of their shape. Stored starch is dissolved not only in the Strasburger
cells which collapse at the same time as the sieve cells but also in the
young sclereids before they incrust their secondary walls with lignin.
The thinly-walled fusiform crystalliferous cells adjust their shape to
a large extent to the growth movement of the surrounding tissue.
Intercellular spaces originate schizogenously and constitute
nearly 20% of the tissue in three year-old, transversely-sectioned phloem.
The histochemical localization of peroxidase and b-glucosidase
activities indicates that these two enzymes not only participate in the
synthesis of lignin but may also play a role in the active expansion of
the cell wall. The observation of the succinic dehydrogenase and cytochromoxidase
activities reveals that the sieve and the Strasburger cells die together
at the latest one year after their differentiation. The acid phosphatase
is detectable mainly in sieve and phloem ray cells, which serve as conductors
of assimilates. |
Gerhard Zbinden |
Promotors, Chemical Pace-Makers
of Carcinogenesis |
2:167-176 |
|
Promotors are substances
which do not cause cancer but have the ability to stimulate growth of cancerous
("initiated") cells. The various biological properties of these agents
were mostly investigated with the help of the mouse-skin model. The possible
relevance of the promotors for human carcinogenesis is discussed. |
Vincent Ziswiler |
Biology in the Period of Enlightenment |
2:177-191 |
|
If; by the period
of enlightenment of a science, one understands its rational infiltration
as being based on an empirical foundation, then one can easily see how
the period of enlightenment in biology and the classical enlightenment
of the time coincide.
The voyages of discovery and the invention of the microscope
opened up new horizons in biology in the 17th century. Besides the purely
descriptive salient points and the cataloguing of living creatures and
their essential parts, there was more and more intellectual interpretation
of biological phenomena, whereby the methodology and axioms of the empirical
and rational philosophers stood the scientists in good stead.
Preferred subjects of discussion during this enlightenment
period were the theory of conception, the search for a natural order, the
question of the variability of species and the interpretation of fossils. |
Wydler,P. |
Lärmbekämpfung - ein
vordringliches Problem. |
2: 193-195 |
Urbanska, Krystyna M. |
Lebensstrategien der Pflanzen von semiariden Ökosystemen
Nordamerikas |
2:196 |
Kahle, Hans-Gert |
Moderne geodätische Messtechniken und ihre Anwendungsmöglichkeiten
in der Geodynamik |
2:196-197 |
Dressler, Kurt |
Moleküle im Weltraum - Molekularspektroskopie |
2:197 |
Gerhard Zbinden |
Promotoren, chemische Schrittmacher bei der Krebsentstehung |
2:197 |
Hünermann, Karl A. |
Tropische Säugetiere als Zeitmarken im Tertiär
des Zürcher Raumes |
2:198 |
Anliker, Max |
Biomedizinische Technik an den Zürcher Hochschulen |
2:198-199 |
Rybach, Ladislaus |
Geothermische Energienutzung in der Schweiz - Möglichkeiten
und Grenzen |
2:199-200 |
Scherrer, Kurt |
Die Satelliten-Bodenstation Leuk |
2:200 |
Landolt, Elias |
Dr.h.c.Walter Höhn-Ochsner (1885-1981) |
2:203-204 |
Niederer, Ueli |
Galileo Galilei and the Rise of Physics |
3: 205-229 |
|
After a short review
of the life of Galileo (1564-1642) two of his principal scientific works
are discussed. The Sidereal Messenger (Sidereus Nuncius, 1610) is important
not only because it contains the first historic results of observations
of the sky with a telescope, among them the discovery of Jupiter's four
moons, but also because it clearly shows the objective and openminded attitude
of Galileo as a scientist. In the Discourses (Discorsi, 1638) Galileo created
the theory of motion as a pure kinematics. Starting from the basic law
according to which the natural fall of a body is a uniformly accelerated
motion, he developed his theory of fall and projectile motion mathematically
and confirmed it by experiments on the inclined plane. The importance of
Galileo however goes beyond his individual results because he put science
on a new basis and set new goals. His science is characterized by three
elements: mathematization, experiment and abstraction. His scientific method
which proceeds through the steps of hypothesis, deduction and confirmation
unites the three elements to the physics we know and of which he was a
founder. |
Kurt Eiberle, Jean-François
Matter und Othmar Wettmann |
On the Population Development
of field Hare in the Canton of Zurich (Switzerland) |
3: 231-245 |
|
The purpose of the
present investigation was to assess the influence of air temperature and
precipitation on the annual kill results of field hare (Lepus europaeus)
in the canton of Zurich in the period of 1930 to 1979. The investigation
showed that the influence of the weather factors at different seasons varies
with the length of time involved and that the monthly meteorological values
show more pronounced dependencies than seasonal values. Air temperatures
were of decisive importance for the population development of the field
hare during the reproductive season. However, the long-lasting consequences
of mild winters too were particularly important since such winters encourage
the outbreak of coccidiosis. Precipitation played merely a subordinate
role within the given general climatic conditions. A combination of the
relevant weather elements made it possible to explain the actual kill development
with a remarkably high coefficient of determination of 87 percent. |
Hans-Niklaus Müller |
The Lateglacial Advances of Gondo
and Zwischbergen (Simplon, Valais, Switzerland) |
3: 247-255 |
|
Moraines in the Zwischbergental
(Simplon, Valais) allow the reconstruction of former glacial surfaces.
From this the lowering of the corresponding equilibrium line altitudes
in relation to a mid-19th century datum level can be calculated.
This reveals a series of glacial advances between the
mouth of the valley at Gondo and the modern glaciers at the head of the
valley, covering the timespan from the Lateglacial until the mid-19th century
maxima.
The lowering of the equilibrium line altitude of the
largest glacial advance amounts to 660 m as compared with 1850. To this
advance the local name «Gondo-Advance» is assigned. It is the
correlative to the Gschnitz-Advance of the Eastern Alps.
Deposits of prominent advances can be found between the
Gschnitz-Advance and the Daun-Advance to which the local name «Zwischbergen-Advance»
is assigned. The lowering of the equilibrium line amounts to 500 m as compared
with 1850. The criteria for the delineation of the Zwischbergen advance
are similar to those which were used for a subdivision of the GschnitzAdvance
in the older literature. |
Max Schüepp |
New Development in Weather forecasts |
3: 257-271 |
|
Development in the
field of weather forecasts during the past 50 years is analysed. Several
changes have taken place. New technical aids have been introduced: Observation
of cloud systems by satellite, precipitation areas by radar and currents
in the free atmosphere by radiosondes and other instrumental methods, e.g.
equilibrated balloons. This material and the Swiss automatic weather stations
have improved the medium range forecasts of modern computers considerably.
The development should lead to a change in the nature of forecasting work:
More persons will be engaged in research, fewer in the daily service. |
Gutermann,Th. |
Internationales Feldexperiment
ALPEX. |
3: 272 |
Wanner,H. |
Eugen A.Thomas. Zum siebzigsten Geburtstag 19.November
1982. |
3: 277-279 |
Sven Björk |
Exploitation, Protection and Management of Tropical Wetlands
- Examples from Jamaica |
4: 281-298 |
|
A plan for peat extraction
is being developed for the Negril (23 km2) and Black River (71 km2) morasses
in Jamaica. The preparatory work for the project is organized in such a
way by the Jamaican authorities that extraction plans are designed in a
joint cooperation between ecologists and engineers.
The Negril morass was badly damaged due to water level
lowering in 1959 and the Black River morass is threatened by a series of
interferences. Investigations carried out so far clearly indicate that
peat extraction offers possibilities to rejuvenate the morasses as wetlands
with a mosaic structure. The ecological preinvestigations include palaeoecological
studies, chemical and physical water and peat analyses and a detailed mapping
of the organism communities. Furthermore experiments concerning structural
and functional development of marsh ecosystems are carried out in lakes
and ponds dug out in the peat. |
Clifford H. Mortimer and Wilfried
Horn |
Internal wave dynamics and their
implications for plankton biology in the Lake of Zurich |
4: 299-318 |
|
Knowledge of wind-induced
displacements of water layers in the Lake of Zurich, the subject of 1949-1951
observations by E. A. Thomas, has been recently extended by multi-position
and multi-depth records of flow and temperature obtained during August
and September 1978 by the "Versuchsanstalt für Wasserbau, Hydrologie
und Glaziologie", ETH, Zurich. The large body of new data, thus acquired,
is still being analysed. Some of the principal findings, relating to internal
seiches and internal surges, are described here. E. A. Thomas also showed
that the storm-induced displacements of the lake's layers from equilibrium
had strong repercussions on the water chemistry and plankton biology of
the lake. That discovery is taken here as a point of departure for speculation
on probable interactions between plankton population dynamics and on the
hydrodynamic events and mechanisms disclosed by the 1978 study.
Particular emphasis is laid on the current shears produced
by the to-and-fro passages of internal surges (travelling as waves of depression
along the thermocline interface) here seen and described in detail for
the first time in the Lake of Zurich. If' after strong wind, the surge
amplitude is large enough, flow in the neighbourhood of the thermocline
will become temporarily unstable, i.e. when the local value of the Richardson
number falls below the critical value of ¼. Vertical mixing by turbulence
will suddenly increase; this will disperse any plankton populations which
are congregated (as often happens) in or near the thermocline; and a pulse
of nutrient-rich subthermocline water will be injected into the often nutrient-starved
layers above. Evidence from the 1978 findings suggests that this type of
instability is very likely to occur, during the stratified season in the
Lake of Zurich, whenever strong currents are generated by wind action or
by the passages of the internal surges, which follow after the wind impulse
has subsided.
The question of whether the surges are reflected at the
basin ends or generated anew by each strong downstroke of the thermocline
is still an open one. The Zurich results suggest that the latter mechanism
is important. |
Roland Pechlaner |
Limnological requirements in protective
hydro-engineering |
4: 319-336 |
|
In connection with
the hydro-engineering measures entailed in flood control there is an increasing
awareness of the necessity for planning and constructing in a manner aimed
at preserving the valuable ecosystems involved. Unfortunately, there is
still too great a discrepancy between what an engineer understands by nature-oriented
water technology and what could be achieved if the limnological specifications
of each stretch of water were to be taken into consideration at the planning
stage. This discrepancy must be reduced at the earliest possible date if
the ecological requirements and technical alternatives are to be combined
to produce the optimum solution for the environment.
In the hope of promoting interdisciplinary cooperation,
the significance of some important milieu factors (current mosaics, temperature
and chemistry of water, light climate) on the diversity and unhindered
development of the plant and animal species, on the ecological equilibrium,
self-cleansing, recreational value and fish yield of mountain streams and
rivers in the Alps will be considered.
In addition, certain problems raised in discussion by
hydro-engineers, with regard to river bed stability, redisposition of bottom
sediments, optimization of methods of step-like regulation, preservation
of meanders and the best type of cross section for the construction in
question are commented upon from the limnologist's point of view.
To ensure that adequate attention is paid to the vast
complexity of factors and situations encountered in aquatic ecosystems
the collaboration of trained specialists whose professional, full-time
occupation lies in the field of limnology is essential. The consistent
employment of suitably qualified limnologists is a vital necessity in the
planning and execution of every project involving hydro-engineering of
inland waters. |
Pierre-André Tschumi, Bruno
Bangerter, Daphne Zbären |
Ten Years of Limnological Research
on Lake Biel (1972-1981) |
4: 337-355 |
|
At the beginning of
the century lake Biel was still oligotrophic. After 1930 its trophic state
changed rapidly and since the sixties the lake has been eutrophic. The
very high nutrient loadings (153 g/m2. a N03-N and 22.5 g/m2 a Pt0t) are
related to the fact that since 1878 the river Aare has been diverted into
the lake. This increased its drainage area 2.6 times. Between 1972 and
1981 the phosphorus loading and concentrations have markedly decreased
due to improved sewage treatment. However, gross primary production rates
remained unchanged (400 g/m2. a C) as also the hypolimnion oxygen consumption
rates (2000 mg/m2. d). From 1973 to 1981 no release of phosphorus from
the sediment could be detected. Phosphorus is incorporated into the sediment
at a rate of 6 g/m2. a.
Phytoplankton biomass and composition change in the course
of the year and from year to year. After the spring algal bloom, a drastic
reduction occurs regularly in early summer accompanied by increased water
transparency. Low radiation and high runoff may contribute to this phenomenon.
However, the main cause seems to be grazing by the zooplankton. Until now
the rotifer and crustacean plankton have been studied. In 1974 and 1978
the crustacean annual production was 40 g/m2 of which 23 g/m2 were lost
in the outflow. |
Ferdinand Schanz |
Light conditions in Lake Zurich
1979-1981 Part I: Secchi disk transparency |
4: 357-367 |
|
In Lake Zurich weekly
measurements of Secchi disk transparency were made over a period of three
years, from 1979-1981. Simultaneously the light intensity and the dry weight
of suspended matter were determined at several depths from the surface
down to 20 metres. Periodically chlorophyll a concentrations were also
measured.
Based on all available data, five periods with similar
properties of transparency can be distinguished during the year. The daily
oscillations of light energy have only a moderate influence on the transparency.
At a Secchi disk depth of 2 metres 22 % of the subsurface light intensity
was measured, at 12 metres 3 00. The exponential decrease found is a result
of the decrease in the concentration of suspended particles which gives
rise to less intense occultation and light scattering. An exponential relationship
between transparency and total extinction coefficient was found. Based
on the data presented in this paper, a theoretical maximum in the Secchi
disk transparency was estimated to be 25 metres. |