Showing papers by "University of Göttingen published in 1975"

Source coding with side information and a converse for degraded broadcast channels

Abstract: Let \{(X_i, Y_i,)\}_{i=1}^{\infty} be a memoryless correlated source with finite alphabets, and let us imagine that one person, encoder 1, observes only X^n = X_1,\cdots,X_n and another person, encoder 2, observes only Y^n = Y_1,\cdots,Y_n . The encoders can produce encoding functions f_n(X^n) and g_n(Y^n) respectively, which are made available to the decoder. We determine the rate region in case the decoder is interested only in knowing Y^n = Y_1,\cdots,Y_n (with small error probability). In Section H of the paper we give a characterization of the capacity region for degraded broadcast channels (DBC's), which was conjectured by Bergmans [11] and is somewhat sharper than the one obtained by Gallager [12].

Investigations on inheritance of quantitative characters in animals by gene markers I. Methods.

Abstract: The method described uses monogenic inherited characters as markers by which the transmission of homologous chromosome sections from parents to progeny can be controlled. The procedure then attributes effects on continuously varying characters to marked chromosome sections. It allows the mapping of effects having a share in quantitative characters in natural or breeding populations.

Models of hearing

Abstract: People have thought about their ears (and those of certain animals) for a long time. Intelligent speculation, supplemented by experiment (and vice versa), has brought us a long way toward understanding how the ear works-from subtle monaural phase effects (verboten by Ohm's law of acoustics) to expansive binaural stereophony (hailed by almost everyone). Much of this new gained knowledge, some of it acquired only very recently, has found its formal expression-as it has in other fields-in models: mathematical models or physical models (or both) of how the ear "does it" ... or might do it if it had been designed by fanciful model builders instead of by pragmatic evolution. In this paper, after a brief introduction into the human ear, a selection of models of both kinds is presented-not with claims of exhaustiveness, but with the intent to give a flavor of what is going on in a very active field on a fascinating, and ultimately still mysterious, subject: man's sense of hearing.

Geochemical controls on a calcite precipitating spring

Abstract: A small spring fed stream was found to precipitate calcite by mainly inorganic processes and in a nonuniform manner. The spring water originated by rainwater falling in a 0.8 km2 basin, infiltrating, and dissolving calcite and dolomite followed by dissolution of gypsum or anhydrite. The Ca2+/Mg2+ indicates that calcite is probably precipitated in the subsurface from a supersaturated solution. This water emerges from the spring still about 5 times supersaturated with respect to calcite and continues calcite precipitation. When 10 times supersaturation is reached, due to CO2 degassing the precipitation is more rapid. The calcite accumulation from the stream with a flow of 5 l/s is calculated to be 12600 kg/yr with the highest rates in areas where CO2 degassing is the greatest. The non-equilibrium, as shown by the high calcite supersaturation, is also reflected in a variable partitioning pattern for Sr2+ between the water and calcite.

Target cell-dependent T cell-mediated lysis of vaccinia virus-infected cells.

Abstract: Vaccinia virus specific cytotoxicity against infected target cells was observed in vitro. Spleen lymphocytes from normal and immunized mice of the inbred strains C3H and DBA/2 were incubated with vaccinia virus-infected and non-infected 51Cr-labeled mastocytoma P-815-X2 cells and L-929 fibroblasts, which were used as targets. Cytotoxic lymphocytes could be isolated from the mice as early as 2 days after infection with vaccinia virus. The highest cytotoxic effect was obtained with lymphocytes taken 6 days after infection. The degree of lysi was correlated with the ratio of immune lymphocytes to target cells. Specific blocking of target cell lysis resulted after addition of anti-vaccinia antibody from different sources. The effector cells could be characterized as T cells by elimination of macrophages and B cells. Target cell killing was only possible in a syngeneic system; allogeneic infected target cells were not lysed significantly.

Lipodystrophy of the extremities. A dominantly inherited syndrome associated with lipatrophic diabetes

Abstract: A female patient with the following symptoms has been observed: complete absence of subcutaneous fat on the arms and legs, well developed adipose tissue on the trunk and face, severe hyperlipidemia, eruptive xanthomas, insulin resistant diabetes mellitus with lack of ketoacidosis, hepatomegaly and elevated basal metabolic rate. The patient thus exhibited all characteristics of lipatrophic diabetes (Lawrence type of diabetes).

On uniqueness of $KMS$ states of one-dimensional quantum lattice systems

Abstract: Uniqueness of KMS states is proved for one-dimensional quantum lattice system. Sakai's theorem on uniqueness of KMS states is generalized to cases of non-commutative generators.

Developmental studies on microbodies in wheat leaves : III. On the photocontrol of microbody development.

Abstract: 1. In etiolated wheat (Triticum aestivum L.) leaves, the development of the microbody enzymes catalase, hydroxypyruvate reductase, and glycolate oxidase was specifically stimulated by short treatments of the seedlings with red light, although the increases were less than observed after treatment with continuous white light. A comparison of the effects of short red and far-red exposures indicated the involvement of phytochrome. 2. Continuous far-red light treatments also enhanced the development of microbody enzymes. Catalase activity continued to increase at a high rate even after return from a prolonged far-red illumination to darkness, while the increase in the activities of glycolate oxidase and hydroxypyruvate reductase fell to the dark rates when the tissue was removed from the light. However, even at higher intensities of continuous far-red light the microbody enzymes reached only considerably lower activities than in white light. During continuous irradiation of equal quantum flux, the microbody enzymes reached higher activities in red than in far-red light, but the highest activities were observed in blue light, which had similar effects as white light. The quantitative difference between the effects of prolonged red or blue light depended also on the seed material and growing conditions. In the presence of the herbicide 3-amino-1,2,4-triazole the increase of glycolate-oxidase activity was reduced in red light but was affected much less, if at all, in blue light. 3. Continuous irradiations with all three light qualities used (red, far-red, blue) influenced the properties of the microbody particles to form a distinct band sharply confined close to an equilibrium density of 1.25 g cm-3 on sucrose gradients which was not observed in preparations from plant material raised in complete darkness. In preparations from all light-grown plants a special peak in the activity profile of malate dehydrogenase was found in the microbody fraction while it was lacking on gradients from dark-grown leaves. The heights of the activities of malate dehydrogenase as well as of the other enzymes found in the microbody fractions from plants grown in either far-red, red, or blue light differed in the same way as did the activities from total leaf homogenates. 4. Glycolate oxidation by segments of intact leaf tissue was higher with tissue from light- than from dark-grown plants, but after light treatments of different spectral quality its magnitude did not correspond to the extractable activities of glycolate oxidase.

Tool marks in bones and cartilage.

Abstract: The identification of the implement used is an important factor in the explantion of the causes of violent deaths. Hitherto existing knowledge has been almost exclusively confined to the damages to skull bones. This paper draws attention to tool marks in the area of pierced rib cartilage and considers the possibilities of their analysis. The evaluation of saw marks is further discussed on the basis of sawing experiments. Also, there are features and peculiarities which can help to solve the problems posed by criminal dismemberment.

Synthesen mit α‐metallierten Isocyaniden, XXIX. Höhere Aminosäuren durch Alkylieren von α‐metallierten α‐Isocyan‐propionsäure‐ und ‐essigsäureestern

Abstract: Aus α-Isocyanpropionsaure-athylester (1a) erhalt man uber die α-metallierten Derivate (2a) mit Alkylierungsmitteln (3) hohere 1-Isocyan-1-methyl-1-alkancarbonsaure-athylester (4). Mit Isocyanessigsaure-athylester (1b) und 3 dominiert die Bis-Alkylierung zu den 1-Isocyan-1-alkancarbonsaureestern 5, mit 1,2-Dibromathan, Bis(2-chlorathyl)-ather und 1,4-Dibrombutan isoliert man die 1-Isocyan-1-cycloalkancarbonsaureester 8, 9, und 10. Beim Isocyanessigsaure-tert-butylester (1c) ist die Mono-Alkylierung zu 6 begunstigt. Die Isocyan-Gruppe hydrolysieren. D.h. die baseninduzierte Alkylierung niederer α-Isocyan-alkancarbonsaureester, gekoppelt mit der Hydrolyse der Isocyan-Gruppe, stellt ein neues Verfahren dar zum Aufbau hoherer Aminosauren. Syntheses with α-Metalated Isocyanides, XXIX. Higher Amino Acids by Alkylation of α-Metalated Ethyl α-Isocyanopropionate and Alkyl Isocyanoacetates Ethyl α-isocyanopropionate (1a) reacts with alkylating agents (3) via the α-metalated derivatives 2a to give higher ethyl α-isocyano-α-methylalkanoates (4). In the reaction of ethyl isocyanoacetate (1b) with 3 bis-alkylation dominates to yield 5. 1,2-Dibromoethane, bis(2-chloroethyl) ether, and 1,4-dibromobutane react with 1b or 1c to form the 1-isocyano-1-cycloalkanecarboxylic esters 8, 9, or 10. With tert-butyl isocyanoacetate (1c), however, monoalkylation occurs to give 6. The isocyano group in the alkylated products can be converted by mild acid hydrolysis to the N-formylamino or amino group. Thus the base-induced alkylation of lower alkyl α-isocyanoalkanoates followed by acid hydrolysis represents a novel route to higher amino acids.

A simple method for the determination of poly-β-hydroxybutyric acid in microbial biomass

Abstract: Poly-β-hydroxybutyric (PHB) acid can be determined IR-spectrophotometrically following chloroform extraction from bacterial biomass. The limit of sensitivity with the present instrument was 50 μg/ml. Interferring triglycerides can be estimated by selective adsorption of PHBS on silica gel.

Gastric inhibitory polypeptide: effect on glucose-induced insulin release from isolated rat pancreatic islets in vitro.

Abstract: Gastric Inhibitory Polypeptide (GIF; 1 or 10 μg/ml) potentiated glucose-induced (8 or 16.6 mM) insulin (IRI) release from isolated rat pancreatic islets. Basal release was unaffected. The threshold concentration of glucose necessary for GIF to modulate IRI release was between 6 and 8 mM. GIP had no effect on IRI release from islets submitted to a maximal glucose stimulus (25 mM).

Fluid Inclusion and Carbon Isotope Study from Bamble Granulites (South Norway)

Abstract: The carbon isotopic composition of CO2 from fluid inclusions in granulite facies rocks has been determined. The “primary” carbonic fluid — most probably being of Upper Mantle origin — appears to have δ 13C-values around −15%. or even lighter up to −20%. During the late stages of retromorphosis an enrichment in the heavy carbon isotope seems to occur resulting in δ-values between −5 and −7%. which, on the basis of 13C/12C ratios of carbonatites, kimberlites and diamonds have been taken up till now as representative for juvenile carbon. The implications of these findings are discussed.

Effects of Thiopental (Trapanal®) on Coronary Blood Flow and Myocardial Metabolism in Man

Abstract: The influence of thiopental (Trapanal®) on coronary blood flow (MBF), myocardial oxygen consumption (MVO2), and general haemodynamics was investigated in seven patients without heart disease. Besides measurement of MBF, the amount of substrates (glucose, lactate, pyruvate and free fatty acids (FFA)) was also determined in arterial and coronary sinus blood samples. Thiopental was given intravenously in a mean dose of 4 mg/kg b.w. MBF was measured by means of the argon method. After injection of thiopental, all seven patients showed a significant increase of MBF and MVO2, a fact which can essentially be explained by the increase of heart rate. The effects of thiopental on arterial concentrations, arterio-coronary substrate differences, myocardial uptake, and O2-extraction ratio of the different substrates are discussed. ZUSAMMENFASSUNG Die Veranderungen der Koronardurchbluting, des myokardialen O2-Verbrauches, der allgemeinen Hamodynamik sowie der wichtigsten Substrate des Herzstoffwechsels unter dem Einflus von Thiopental wurden an insgesamt 7 herzgesunden Patienten untersucht. Die verabreichte i.v., Dosis von Thiopental betrug 4 mg/kg Korpergewicht. Die Koronardurchblutng wurde mittles der Argon-Fremdgasmethode bestimmt. Nach Injektion von Thiopental in der angegebenen Dosierung kam es bei allen Patienten zu einem signifikanten Anstieg desMBF und des MVO2, eine Tatsache, die im wesentlichen mit der Herzfrequenzsteigerung erklart werden kann. Der Einfluss von Thiopental auf die arteriellen Substratkonzentrationen, auf die Substrataufnahme und Sauerstoffextraktionsquotienten werden diskutiert.

Homogeneous thermal oxidation of methane in reflected shock waves

Abstract: The homogeneous thermal oxidation of methane-oxygen mixtures, highly diluted with argon, was investigated in shock waves by following emission and absorption of various species during the course of the reaction. The equivalence ratio =2[CH 4 ]/[O 2 ] was various from 0.2 to 2.0. The total density extended from 2·10 −5 to 2·10 −3 mole/cm 3 , corresponding to pressures from 3 to 200 atm at 1800 o K. In the present paper data on induction periods for the oxidation of these mixtures are reported for a very wide range of experimental conditions. For mixtures with more than 1% methane and oxygen, and toward higher densities, the following expression describes the induction period τ i − 2.5 · 10 − 15 [ C H 4 ] 0.25 [ O 2 ] − 1.02 [ A r ] 0.0 exp ⁡ + 222 k J m o l R T [ s ] concentrations in mole/cm 3 For very dilute mixtures the experiments indicate an increase of the apparent activation energies and a change in the concentration dependence of τ i .

Soil and Compost Filters of Malodorant Gases

Abstract: Removing low concentrations of pollutant gases from air streams is difficult and expensive.1,2 Removal techniques include water scrubbing (with and without permanganate, hypochlorite, or lime), burning, and sorption by activated charcoal. The shortcomings of these techniques are that they require fuel, maintenance, water, high capital costs, they pollute the wash water, and/or some concentrate only, rather than remove the offender.

Vektorbündel vom rang 2 über dem n-dimensionalen komplex-projektiven raum

Abstract: In this paper we construct holomorphic vector-bundles of rank 2 on complex-projective spaces to canonical data. More detailed results for the projective plane are given.

Massenspektrometrische Untersuchungen über Erzeugung und Reaktionen von C2H‐Radikalen

Abstract: Bei der massenspektrometrischen Analyse der im Plasma von Mikrowellenentladungen in Bromacetylen-Helium-Gemischen gebildeten Teilchen konnten u. a. die Radikale C, C2 und C2H nachgewiesen und deren Konzentrationsabfall nach Verlassen der Entladungszone in Abhangigkeit von der Reaktionszeit verfolgt werden. Durch Einstellung geeigneter Entladungsstarken liesen sich maximale Konzentrationen bestimmter Teilchen erzeugen: so konnten bei geringer Entladungsenergie relativ hohe C2H-Konzentrationen dargestellt werden. Von dieser Tatsache wurde zur Untersuchung der Reaktionen des C2H-Radikals mit H2, O2 und C2H2 Gebrauch gemacht. In a masspectrometric analysis of the products of a microwave-flow-discharge in bromoacetylene-helium-mixtures the radicals C, C2 and C2H were identified, and their concentrations were monitored downstream of the discharge as a function of reaction-time. By ad-lusting the discharge energy, a maximum concentration of a given radical generated in the plasma could be obtained. In this way relatively high C2H-concentrations were produced at low discharge energy. This was taken as a good opportunity to study the reaction of C2H with H2, O2 and C2H2.

Kinkenbildung in geladenen Versetzungen

Abstract: Es wird vorgeschlagen, die beobachtete Abhangigkeit der Versetzungsgeschwindigkeit in einem Halbleiter von seiner Dotierung durch einen elektrostatischen Beitrag zur Kinken-bildungsenergie zu erklaren. Dieser ist vollstandig bekannt, wenn die Ladung auf der Versetzung aus Messungen des Halleffektes bestimmt wird. Die Theorie gibt die Dotierungs-abhangigkeit der Kinkenbildungsenergie richtig wieder, allerdings nicht ihre Temperatur-abhangigkeit. Auf eine Anwendung der Theorie zur Erklarung des „chemo-mechanischen Effekts” wird hingewiesen. It is proposed to explain the dependence of the dislocation velocity in a semiconductor on doping by an electrostatic contribution to the kink formation energy. This can be calculated from the dislocation charge as determined by Hall measurements. The theory seems to explain well the effect of doping on the kink formation energy, although it is difficult to understand why this is rather temperature independent. The theory may help to understand the “chemomechanical effect”.

Three‐Dimensional Structure of the Actinomycins

Abstract: Many complicated three-dimensional structures can be formulated for the actinomycins, red chromopeptide antibiotics distinguished by pronounced antineoplastic activity, because of their unique constitutional type. Since these structures largely determine the specific activity of the actinomycin molecules in the host cells, knowledge of the structural forms occurring naturally in solution is a decisive prerequisite for detailed insight into the mode of biological action of the actinomycins. Investigations by several methods have shown that, in spite of their deviating primary structures, all important actinomycins assume only one very characteristic, pseudo-C2-symmetrical, and remarkably stable three-dimensional structural type.