Showing papers by "ETH Zurich published in 1971"
TL;DR: It is concluded that although the equilibrium conformation of the amide group may be planar or close to it, out-of-plane deformation can be made at a very modest energy cost.
319 citations
TL;DR: In this article, the authors discuss proposals for testing the presence of phase relations and for extracting them quantitatively by means of numerical bispectrum analysis, and derive their statistical properties and compare their relative merits.
Abstract: Harmonically related peaks in the spectrum of a stationary stochastic process may indicate the presence or wave components that are not sine-shaped, i.e., whose Fourier expansions contain phase-locked higher order terms. But the spectrum itself suppresses phase relations, and more refined methods are needed to decide such questions. Moreover, phase relations might also exist outside of the peaks. We discuss proposals for testing the presence of phase relations and for extracting them quantitatively by means of numerical bispectrum analysis, and we derive their statistical properties and compare their relative merits. Applications of these methods to EEG signals will be presented.
206 citations
TL;DR: The bispectrum allows a detailed analysis of the third central moment, which is influenced either by interrelations between frequency components or by non-stationarity of the signal, and may therefore display important additional information about the properties of a stochastic signal like the EEG.
109 citations
TL;DR: The Franciscan melange was pervasively sheared when the North American plate rode over a Cretaceous Neo-Franciscan plate as mentioned in this paper, and the densely spaced shear surfaces within the melange signify a westward migration of the plate junction as it was being underthrust.
Abstract: The traditional view representing eugeosynclines as elongate troughs having active volcanism is challenged. Eugeosynclinal rocks are commonly tectonic melanges, representing mixtures of rocks derived from more than one realm of deposition. The Franciscan melange includes ophiolites emplaced at a mid-ocean ridge, radiolarites deposited on an abyssal plain, and flysch turbidites poured into a deep-sea trench. The Franciscan melange was pervasively sheared when the North American plate rode over a Cretaceous Neo-Franciscan plate. The plate junction is not a single overthrust surface. The densely spaced shear surfaces within the melange signify a westward migration of the plate junction as the Franciscan was being underthrust. The Franciscan glaucophane schists, metamorphosed under very high pressure 130–150 m.y. ago, record a pre-Cretaceous Franciscan history. Geological evidence suggests that those once deeply buried rocks were squeezed out during a Late Jurassic alpine type of deformation (Nevadan orogeny), when the North American continent collided with a micro-continent (Salinia). The Cretaceous underthrusting along a consuming plate margin resulted in melange deformation and in lawsonite-schist metamorphism of the neo-Franciscan rocks, which are coeval with the Great Valley sequence.
100 citations
TL;DR: In this paper, a Ubersicht uber Messungen der Stofftransportgeschwindigkeit an gasentwickelnden Elektroden gegeben is given.
Abstract: Nach einer Beschreibung der elektrolytischen Gasentwicklung, die in drei Schritten (Keimbildung, Wachstum und Ablosen der Blasen) erfolgt, wird eine Ubersicht uber Messungen der Stofftransportgeschwindigkeit an gasentwickelnden Elektroden gegeben Bei H2-Entwicklung ist die effektive Diffusionsschichtdicke δN umgekehrt proportional der Wurzel der Gasentwicklungsgeschwindigkeit Bei Stromdichten von etwa 1 A/cm2 betragt δN nur einige μm Es werden Schlusfolgerungen fur die Praxis und einige Anwendungsbeispiele der experimentell erhaltenen Korrelationen beschrieben sowie ein theoretisches Modell fur den Stofftransport bei Gasentwicklung diskutiert Zum Vergleich wurden auch die Stofftransportgeschwindigkeiten bei Einleiten von Fremdgas in die Zelle gemessen Es ergaben sich hier keine so hohen Stoffubergangszahlen wie bei Gasentwicklung an der Elektrode; sie sind jedoch um eine Grosenordnung hoher als bei naturlicher Konvektion
90 citations
TL;DR: Die P-helikale Anordnung bedingt nach der Theorie von Linderberg & Michl einen negativen Rotationsbeitrag der langwelligsten asymmetrischen Absorptionsbande, was mit unseren CD.-Versuchen nun erstmals experimentell bestatigt wird.
Abstract: Im synthetischen [2, 7-Cystin]-Gramicidin S ist der Cyclodecapeptid-Ring mit einer Disulfidgruppe uberbruckt. NMR.-Untersuchungen zeigen, dass die Peptidkette der Verbindung (wie beim Gramicidin S) in der antiparallelen β-Konstellation vorliegt. Auf Grund von Abschirmungs-Effekten kann der Disulfid-Brucke die P-helikale Chiralitat zugewiesen werden. In Molekel-Modellen betragt der dihedrale Winkel φ etwa 120°. Die P-helikale Anordnung, verbunden mit |90°| < |φ| < 180°|, bedingt nach der Theorie von Linderberg & Michl einen negativen Rotationsbeitrag der langwelligsten asymmetrischen Absorptionsbande, was mit unseren CD.-Versuchen nun erstmals experimentell bestatigt wird (λmin = 271,5 nm, Θ = -7550, Athanol). Auch der theoretisch geforderte zweite Cotton-Effekt mit umgekehrtem Vorzeichen kann bei dieser Modellverbindung gut beobachtet werden (λmax = 230 nm, Θ = +60870, Athanol); allerdings sind in diesem Bereiche Beitrage von Peptid-n π*-Ubergangen nicht a priori auszuschliessen, was den diagnostischen wert dieser Bande vermindert.
90 citations
TL;DR: The origin of the Alpine geosyncline may have been related to the eastward motion of Africa relative to Europe during the Mesozoic, and orogenesis in western Europe could have been caused by a westward and then a northward movement of Africa.
Abstract: The origin of the Alpine geosyncline may have been related to the eastward motion of Africa relative to Europe during the Mesozoic, and orogenesis in western Europe could have been caused by a westward and then a northward movement of Africa.
79 citations
TL;DR: Synthese und Eigenschaften des p-Azido-L-phenylalanins und einiger seiner fur die PeptidsyNThese geeigneter Derivate werden beschrieben.
Abstract: Synthese und Eigenschaften des p-Azido-L-phenylalanins (1) und einiger seiner fur die Peptidsynthese geeigneter Derivate werden beschrieben. Infolge der photolytischen Spaltbarkeit in Stickstoff und das Imen 2 durfte dieses Analogon des Tyrosins als «photochemische Affinitatssonde» verwendbar sein.
79 citations
TL;DR: In this article, a new antiferromagnetic phase in EuSe was found to occur below 1.8 K in external magnetic fields smaller than 500 oe, and the spin structure of this phase is of the MnO-type.
71 citations
TL;DR: The fine structure of the cell envelopes of vegetative aerial hyphae and spores of Streptomyces coelicolor was studied by means of freeze-etching and negative staining.
64 citations
TL;DR: Aleurone tissue from non-germinated or germinating barley seeds, as well as from isolated aleurone layers imbibed with water or gibberellic acid, was frozen directly in Freon and investigated by the freeze-etching technique.
Abstract: Aleurone tissue from non-germinated or germinating barley seeds, as well as from isolated aleurone layers imbibed with water or gibberellic acid, was frozen directly in Freon and investigated by the freeze-etching technique. Aleurone grains remained spherical under all conditions, although the volume increased on hydration. They contained both protein crystalloids and globoids (phytin or lipid) embedded in the matrix. Globoids appeared to be membrane-enclosed. Spherosomes were evidently enclosed within a normal membrane, and they were in close contact with the membrane of aleurone grains, covering the surfaces of the latter. A highly-ordered particle structure was seen on some preparations of the plasmalemma. During germination no alterations were observed in membrane structure.
TL;DR: Spearman's correlation coefficients mean that subjects with a marked decrease in CFF or in grid tapping performance have a greater tendency to ‘ tired...
Abstract: Fatigue was measured on 68 air traffic controllers using the following methods: critical fusion frequency (CFF), tapping test, grid tapping test, self-rating. The measurements were taken 9 times within 24 hours over 3 weeks. Stress was measured on the basis of a questionnaire and of catecholamine excretion in urine. The four fatigue tests showed significant agreement. There was a marked decrease in the values after the 6th hour of work. During the night hours, the test values were lower, and the subjects stated they were more tired. For the first work hour and for the 9th to 11th work hour Spearman's correlation coefficients between the two sets of data were calculated. A significant correlation was found (a) between CFF and grid tapping (p<0·02); (b) between CFF and self-rating ‘ refreshed-tired ’ (p<0·05); (c) between grid tapping and self-rating ‘ refreshed-tired ’ (p<0·02). This means that subjects with a marked decrease in CFF or in grid tapping performance have a greater tendency to ‘ tired...
TL;DR: Cells of Saccharomyces cerevisiae that have been growing exponentially for many generations contain low activities of lysosomal enzymes, but differentiating or resting cells contain comparatively high activities of these enzymes.
Abstract: Cells of Saccharomyces cerevisiae that have been growing exponentially for many generations contain low activities of lysosomal enzymes. In contrast to such fully adapted cells, differentiating or resting cells contain comparatively high activities of these enzymes. Thus, the digestive enzymes seem to be involved in the process of biochemical differentiation.
TL;DR: The presence of large vesicles in the degenerating nerve terminals was shown to be independent of the method of fixation: paraformaldehyde, glutaraldehyde and acrolein with subseunt osmication gave essentially similar results to those obtained with osmic acid fixation alone.
TL;DR: In this paper, measurements of the differential cross section and the effective mass distribution of three-and five-pion coherent production on nuclei from Be to Pb are presented.
TL;DR: Comparison of the data on methionine coordination with data on the ability of the modified cytochromes c to restore the respiration of cytochrome c -depleted rat liver mitochondria indicates that the redox carrier properties of cy tochrome c are maintained only if meth ionine is bound to the heme iron in the oxidized and the reduced form.
01 May 1971
TL;DR: The optical constants of Eu-chalcogenide single crystals have been determined at room temperature for photon energies from 1 to 6 eV as discussed by the authors, and the transmission of thin evaporated films (except for EuO) has been measured with polarized light above and below the magnetic ordering temperature.
Abstract: The optical constants of Eu-chalcogenide single crystals have been determined at room temperature for photon energies from 1 to 6 eV. In the same energy range the transmission of thin evaporated films (except for EuO) has been measured with polarized light above and below the magnetic ordering temperature. The observed polarization-dependent splittings of the two main absorption maxima in the region of magnetic order suggest transitions from the 4f7-level into the crystal field split 5dt2g- and 5deg-states.
TL;DR: In this paper, a Schrittverfahren zur numerischen integration of gestorten linearen Differentialgleichungssystemen aufgestellt is presented.
Abstract: Es wird ein Schrittverfahren zur numerischen Integration von gestorten linearen Differentialgleichungssystemen aufgestellt. Die Grundlage dazu bildet die Definition einer Folge von ganzen Funktionen, die keine Polynome sind, aber eine einfache Potenzreihendarstellung besitzen. Im Gegensatz zu den ublichen Potenzreihenverfahren, wird nicht nach Potenzen der unabhangigen Variabeln, sondern nach diesen Funktionen entwickelt. Das Integrationsverfahren hat die Eigenschaft, dass die ungestorten Differentialgleichungen ohne Diskretisationsfehler integriert werden, und dass die Eigenwerte der Koeffizientenmatrix nicht berechnet werden mussen. Die Verbesserung gegenuber der gewohnlichen Potenzreihenmethode wird durch asymptotische Formeln fur die Residuen und durch numerische Beispiele belegt. Nach einer Einleitung uber Ziel und Zweck der Arbeit wird die Methode anhand eine: gestorten linearen Differentialgleichung zweiter Ordnung illustriert. Anschliessend wird das Integrationsverfahren auf beliebige gestorte lineare Systeme verallgemeinert.
TL;DR: The Ultrahelvetic Flysch basin was identified in this paper as the origin of the Flysch basins by the descent of the northward-moving Penninic plate under an island arc which was at the leading edge of the Helvetic plate.
Abstract: Arguments are presented to support the proposition that Ultrahelvetic Flysch basins were present on both sides of the Habkern island arc that was convex to the southeast during Paleocene time. The width of this Ultrahelvetic realm of sedimentation is estimated to have been at least 300 km in a northwest-southeast direction; this estimate is based upon comparison with the geometrical dimensions of modern basins and on paleoecological considerations. The deformational history of the Ultrahelvetic Flysch is interpreted in terms of plate tectonics. Two plates were involved, a Helvetic plate and a Penninic plate. The origin of the Flysch basins was related to the descent of the northward-moving Penninic plate under an island arc which was at the leading edge of the Helvetic plate. During late Eocene and early Oligocene, a plate flip took place and the Helvetic plate then descended below the Penninic plate. This reversal in plate relationships accounts for the occurrence of the discordant Bergell Pluton and concurrent andesitic volcanism, which supplied detritus to the North Helvetic Flysch.
TL;DR: Micrographs obtained from freeze-fractured monkey, cat, and rat spinal cord, cerebral cortex, and subfornical organ as well as from pigeon optic tectum suggest a special type of affinity between the two elements and indicate that presynaptic membranes may be involved.
Abstract: That synaptic vesicles with a diameter of about 50 nm could be demonstrated by the freeze-fracturing technique was an important contribution to the knowledge of synaptic fine structure (Moor, Pfenninger & Akert 1969; Akert, Moor, Pfenninger & Sandri 1969). The finding u spheric profiles (figures 1, 3 a, c) in rapidly frozen tissue renders an artefactual origin of vesicles very unlikely. However, the chief advantage of freeze-fracturing lies in the visualization of membrane surfaces which are of special interest in presynaptic nerve terminals. The present micrographs were obtained from freeze-fractured monkey, cat, and rat spinal cord, cerebral cortex, and subfornical organ as well as from pigeon optic tectum. Special attention was paid to areas in which large pieces of membranes remained attached to the surfaces of nerve cells (figures 1, 3 a ). This situation suggests a special type of affinity between the two elements, and the association of one of the membranes with clusters of synaptic vesicles indicates that presynaptic membranes may be involved.
TL;DR: Electron microscope observations based on the freeze-etching method indicate that the membranes are structurally complex entities, showing a consistent pattern of polarity and similarities of particle type and distribution.
Abstract: Publisher Summary Freeze-etching permits the study of four different views of a membrane. When isolated membrane vesicles are frozen and the ice subsequently removed by sublimation, the real outer or inner surface is disclosed. These surfaces are covered by a number of particles attached to a smooth layer. With a new double-fracturing method, the inner structure of a membrane can also be studied. It is evident that the middle layer is made up of particles. During fracturing, the particles are distributed between the two parts of the cleaved membrane. In the same type of membrane one type of particles is always removed from each side, which indicates that they must be anchored in the outer strata. It is postulated that the bulk of lipids is located at both surfaces and not in a central bilayer. Electron microscope observations based on the freeze-etching method indicate that the membranes are structurally complex entities, showing a consistent pattern of polarity and similarities of particle type and distribution. This view reflects the diversity of membrane function more adequately than the older concepts.
TL;DR: The increasing importance of high-temperature materials for science and technology has in the last ten years created a great demand for single crystals of compounds with a high melting point as discussed by the authors.
TL;DR: Mit Hilfe der Antennogramm-Methode wurdetrans-11-Tetracedenylacetat als spezifisches Attraktans für Männchen des LärchenwicklersZeiraphera diniana bestimmt.
Abstract: Mit Hilfe der Antennogramm-Methode wurdetrans-11-Tetracedenylacetat als spezifisches Attraktans fur Mannchen des LarchenwicklersZeiraphera diniana bestimmt. In geeigneter Konzentration ist die Attraktivitat der synthetischen Substanz derjenigen virginer Weibchen ebenburtig.
TL;DR: In this paper, the effect of shear forces and other stress components on the buckling load of a prismatic bar of arbitrary slenderness, hinged at both ends, was considered for the cases of narrow rectangular (plane stress or strain) and elliptic cross sections.
Abstract: The effect of shear forces and other stress components on the buckling load of a prismatic bar of arbitrary slenderness, hinged at both ends, is considered for the cases of narrow rectangular (plane stress or strain) and elliptic cross sections (three-dimensional problem). The problem is solved, using the asymptotic method, and the buckling loads are obtained as series with increasingly minor corrections.
01 Mar 1971
TL;DR: In this paper, the authors present a Messung of the Lichtverhältnisse of anorganischen Stickstoffkoraponenten in the Kjeldahl-Methode.
Abstract: M e t h o d e n P h y s i k a l i s c h e M e t h o d e n . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Terapera tu rmessung . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Messung der Lichtverh~ltnisse " . . . . . . . . . . . . . . . . . . . . . . . 5 C h ~ i s c h e A n a l y s e n m e t h o d ~ n . . . . . . . . . . . . . . . . . . . . . . . . . 5 Bes t immung der anorganischen Stickstoffkoraponenten . . . . . . . . . . . . . 5 Bes t immung der organischen Stickstoffkoraponenten . . . . . . . . . . . . . . 5 Bes t i ramung des part ikul~ren organischen Stickstoffs rait der Kjeldahl-Methode . . 6 Bes t immung des gel6sten organischen Kjeldahl-Stickstoffs . . . . . . . . . . . 8 Bestinu'~ung des Kjeldahl-Stickstoffs ira aufgefangenen Sediment . . . . . . . . 10 Bes t i rnmung der Phosphorkomponenten . . . . . . . . . . . . . . . . . . . 10 Bestirrtraung des gel6sten Sauerstoffs und des Sulfids . . . . . . . . . . . . . . 10 Bes t immung des anorganischen Gesaratkohlenstoffs . . . . . . . . . . . . . . 10 B i o l o g i s c ~ U n t e r s u c h u n g s m e t h o d e n . . . . . . . . . . . . . . . . . . . . . . 10 Produkt ionsr~essung Knit der CXt-Methode . . . . . . . . . . . . . . . . . . 10 P lank tonun te r suchungen . . . . . . . . . . . . . . . . . . . . . . . . . . 11
TL;DR: In this paper, the authors give a function-theoretic proof that complete intersections of dimensions greater than three which have isolated singularities have local rings which are unique factorization domains.
Abstract: Let (X,
x
O) be a normal complex analytic space andA⋐X a connected Stein compact set, i.e. a compact subset ofX which has a basis of open neighborhoods which are Stein spaces. We restrict attention to thoseA such thatR=H
0
O) is Noetherian. In Section I various exact sequences involving the divisor class group ofR, denotedC(R), are developed. (IfA is a point, one of these sequences is well-known [24], [39].) LetB be a connected compact Stein set on a normal varietyY such thatS=H
o(B,
Y
O) andT=H
o(A×B,
X×Y
O are Noetherian. In II we give a Kunneth-type formula which relatesC(R), C(S) andC(T). In III we show certain analytic local rings are unique factorization domains, study the divisor class groups of local rings on the quotient of an analytic space by a finite group, and prove a simple result on the topology of germs of complex analytic sets. We give a function-theoretic proof that complete intersections of dimensions greater than three which have isolated singularities have local rings which are unique factorization domains.
TL;DR: In this paper, the authors showed that Europium orthosilicate can be stabilized at room temperature only if Eu 3+ is present, and that the orthorhombic structure can not be stabilized by sublimation, solidification, or solid state reaction.
TL;DR: Eggs and embryos of the viviparous paedogenetic gallmidge Heteropeza pygmaea can be cultivated in vitro throughout the entire period of egg follicle growth and embryonic development.
Abstract: Eggs and embryos of the viviparous paedogenetic gallmidge Heteropeza pygmaea can be cultivated in vitro throughout the entire period of egg follicle growth and embryonic development. During this process they increase in volume more than 100 times. The culture medium, consisting of hemolymph and fat body cells, is obtained from Z-ray sterilized, full grown larvae of the same species. Embryonic development in this medium is essentially the same as it is in vivo.
If the fat body cells of the culture medium have been damaged during their explanation, the embryos on the culture show vacuoles in their yolk syncytium after some time and do no develop further. If all fat body cells in a preparation stay intact, some of the embryos develop completely, whereas the others dissolve. Intact fat body lobes can not be used for in vitro culture, because they generally show degeneration which prevents embryonic development.
The suitability of the culture method is discussed.