Showing papers by "University of Bremen published in 1981"

Concepts of Vestibular Compensation

Abstract: Peripheral vestibular lesions such as unilateral labyrinthectomy or unilateral vestibular nerve transection result in characteristic gross disturbances of posture and movement. These symptoms disappear spontaneously with time and normal behavior is restored. This compensation process encompasses all observed deficits. The pattern of disturbances following the lesion and the time course of the compensation processes are basically similar but not identical in different vertebrates. A detailed description of the similarities and differences in the symptomatology and recovery processes in different species is given by Schaefer and Meyer (1974). The basic phenomena of the compensation process have been well known since the classical investigations of Bechterew (1883) and Ewald (1892). Magnus (1924) realized that compensation must involve an extensive reorganization of the remaining structures of the vestibular system.

Heterogeneous Labour and the Fundamental Marxian Theorem

Abstract: As was pointed out by Morishima at the end of his famous book on Marx's Economics, the heterogeneity of labour is a "serious dilemma" for Marx's theory of exploitation, especially for the so called Fundamental Marxian Theorem. The problem, which should be separated from the peculiarities of joint production, consists in finding an appropriate reduction of the various types of labour to one common unit. Recently Bowles and Gintis have undertaken an interesting reformulation of the Marxian theory of value with respect to heterogeneous labour by avoiding any reduction at all (Bowles and Gintis 1977, 1978. Cf. also Steedman 1977, Holliinder 1978). But for the purpose of the Fundamental Marxian Theorem this only shifts the problem from the heterogeneity of labour to the heterogeneity of the respective rates of exploitation. The aim of the present paper is to extend the Fundamental Marxian Theorem (without joint production) from homogeneous to heterogeneous labour (Section 3). This extension is based on a new concept called the standard reduction of labour, because of its dual relationship to Sraffa's standard commodity (Section 2). For some arguments a certain type of matrices, called Sraffa matrices, is needed, which generalize the quasiirreducible matrices as introduced by Bowles and Gintis (Appendix). Standard reduction implies always a uniform rate of exploitation, whereas the same is true for the reduction by wage rates only in special cases (for example: uniform consumption; labour inputs only; prices proportional to labour values. For the first two cases cf. Morishima 1978). Hence, in general standard reduction and reduction by wage rates are different.

Evidence for cellular circadian rhythms in isolated fluorescent dye-labelled salivary glands of wild type and an arrhythmic mutant ofDrosophila melanogaster

Abstract: Fluorescence intensity of isolated salivary gland cells of wild-type and arrhythmic (pero)Drosophila melanogaster larvae was measured in constant conditions. The glands were incubated in a medium containing 3.5×10−6M 3,3′-dihexyl-oxacarbocyanine iodide for which cellular concentrations is probably controlled by the membrane potential. In wild-type cells significant rhythmicity of fluorescence intensity was measured over the cytoplasmic as well as the nuclear areas. In pero cells, arrhythmic and rhythmic changes were registered, the latter showing lower amplitudes. We conclude that the decreased amplitude and the lower number of significant cellular rhythms in pero mutants might lead to an apparent arrhythmicity at the behavioural level, i.e. activity and eclosion.

A non-empirical molecular orbital study on loewenstein's rule and zeolite composition

Abstract: The role of the “aluminum avoidance rule” in zeolite frameworks and its relation to the electronic structure and stability of various structural units of alumosilicates were studied by non-empirical SCF—MO techniques. Al—O—Al-type linkages are unstable according to the calculations. The presence of cations in the neighbourhood of T1—O—T2 bridges (T1, T2 = Si or Al) is the least stabilizing when T1 = T2 = Al.

Oxidative Additionen an 2‐Amino‐4,4,5,5‐tetrakis(trifluormethyl)‐1,3,2‐dioxaphospholan

Abstract: Durch oxidative Addition von HF, Cl2 und (CF3)2CO and die Titelverbindung 6 entstehen die Phosphorane 2, 9 und 3; mit NH4[OC(CF3)2C(CF3)2OH] (4) wird unter Abspaltung von NH3 und oxidativer Addition das Hydrophosphoran 1 erhalten. Durch Substitution von Chlor lassen sich aus 9 die Aminoalkoxyphosphorane 5 und 8 synthetisieren, wahrend die Thermolyse unter HCl-Abspaltung zu dem auserst bestandigen Phosphazen 10 fuhrt. Verbindung 3 zeigt im 19F-NMR-Spektrum wegen eingeschrankter dynamischer Prozesse acht magnetisch nicht aquivalente CF3-Gruppen. Durch 19F-Homoentkopplungsexperimente werden weitreichende Raumkopplungen nachgewiesen. Die Rontgenstrukturanalyse von 3 ergibt eine annahernd trigonal-bipyramidale Koordination des Phosphors, F2PNH2 und tBu2PNH2, zur vergleichenden Betrachtung herangezogen, reagieren mit Hexafluoraceton unter Bildung von (CF3)2CNH sowie des Amino-fluorphosphorans 11 und des Phosphorsaureesters F2P(O)OCH(CF3)2 (13) bzw. von tBu2P(O)H (12) und tBu2P(O)OCH(CF3)2 (14). Oxidative Additions to 2-Amino-4,4,5,5-tetrakis(trifluoromethyl)-1,3,2-dioxaphospholane Oxidative addition of HF, Cl2 and (CF3)2CO to the title compound 6 furnishes the phosphoranes 2, 9, and 3, respectively. In the case of NH4[OC(CF3)C(CF3)2OH] (4) the hydrospirophosphorane 1 is obtained via a substitution reaction followed by an oxidative addition. Compound 9 is a precursor for the aminotetraalkoxyphosphoranes 5, 8, and the very stable phosphazene 10 which is formed by loss of HCl by thermolysis. Due to a slow ligand exchange the 19F NMR spectrum of phosphorane 3 exhibits eight magnetically non equivalent CF3 groups. By means of 19F homodecoupling experiments extensive through space coupling is found in the molecule. The x-ray structure analysis of 3 shows a slight distortion from the trigonal bipyramidal geometry at phosphorus. For comparison, F2PNH2 and tBu2PNH2 react with (CF3)2 to form (CF3)2CNH, the aminofluorophosphorane 11, F2P(O)OCH(CF3)2 (13) bzw. von tBu2P(o) (12) and tBu2P(O)OCH(CF3)2 (14), respectively.

Homogeneous Spaces from a Complex Analytic Viewpoint

Abstract: Manifolds having many automorphisms play a fundamental role in geometry. If X is a compact complex manifold, then the group Aut(X) of holomorphic automorphisms of X is, when equipped with the compact-open topology, a complex Lie group. If G = Aut(X), then an orbit G(p) , p∈X, may be holomorphical ly identified with the quotient manifold G/H, where H := {g ∈ G|g(p) = p} is the isotropy group of the G-action at p. Thus, studying quotients G/H of a complex Lie group G by a closed subgroup H becomes relevant. A natural first step is to analyze the structure of compact homogeneous spaces X = G/H. In the early 1950’s, with development of Lie theory along with the theory of algebraic groups, a number of very sharp results were obtained by algebraic methods. The works of Borel (e.g., [10]), Goto [22], Tits [64] and Wang [67] are typical of this direction. Later, but still in an algebraic geometry spirit, many general methods were developed (e.g., see the papers of Hochschild, Mostow, Rosenlicht et al.).

Polymere Phthalocyanine und ihre Vorstufen, 3. In situ Gasphasensynthese und einführende elektrochemische Charakterisierung polymerer Phthalocyanine auf metallischen Trägern†‡

Abstract: The gas phase reaction of 1,2,4,5-tetracyanobenzene (3) with metal sheets like Cu, Ni, Co, Fe, and Ti exhibits the in situ formation of polymeric phthalocyanine coatings 1. The electrochemical behaviour of layers of 1 is investigated by means of cyclic voltametric measurements. Determination of layer-thickness and electrical resistance is also performed.

Melatonin Rhythms in Human Serum

Abstract: Publisher Summary This chapter discusses melatonin rhythms in human serum. In a study described in the chapter, the circadian rhythm of the melatonin serum concentration (MSC) was ascertained by melatonin determinations at time differences. The test persons did not take medicaments and/or contraceptives. All investigators who determined human melatonin agreed that the secretion of the hormone in man exhibits a circadian rhythmicity. The age-dependence of the MSC is established in the circadian rhythmicity. During the menstrual cycle, the melatonin secretion exhibits a circadian rhythm. The circadian rhythm of the melatonin serum level stays at the first day of cycle, at the ovulation time and in the third decade of the menstrual cycle. The circadian rhythm of the MSC is a basic rhythm, where menstrual cycle—and seasonal—sub-rhythms influence the basic rhythm as a whole.

Low-Insertion-Loss Fin-Line Filters for Millimetre-Wave Applications

Abstract: A design theory is described for low-insertion-loss fin-line filters with fin-line gap widths over the total height of the waveguide housing. The theory includes both higher order mode propagation and the finite thicknesses of the dielectric and the metallic fins. An evolution strategy synthesis method yields optimum design data for three- and five resonator-type fin-line filters with several substrate thicknesses. The midband frequencies chosen are about 13, 34, 66, and 75 GHz. Measured minimum insertion-losses in the passband are about 0.2 dB (13 GHz), 0.5 dB (34 GHz), and 1.9 dB (65 GHz) for three-resonator-type filters as an example.

Ruthenium complexes with diazadienes. I. Synthesis and crystal structure ofcis-Ru(dad)2Cl2 (dad = 2,7-dimethyl-3,6-diaza-3,5-octadiene)

Abstract: Reduction of RuCl3 · 3 H2O in the presence of the title diazadiene i-PrN=CH-CH=NPr-i (from the condensation of glyoxal and isopropylamine) gives the intensely colouredcis-Ru(dad)2Cl2 (2) in moderate yield. The crystal and molecular structure was determined by x-ray diffraction. Complex (2) crystallizes in space group P ¯1 witha = 1110.2(10),b = 1360.3(6) andc = 1427.6(8) pm;a = 85.05(4), β = 79.07(6) and γ=82.65(6)° with four molecules in the unit cell. Electronic and1H n.m.r. spectra are discussed. An abnormally small vicinal coupling of the azomethine protons is detected.