Showing papers by "Heidelberg University published in 1980"
TL;DR: In this paper, the authors present a class of C*-algebras and point out its close relationship to topological Markov chains, whose theory is part of symbolic dynamics.
Abstract: In this paper we present a class of C*-algebras and point out its close relationship to topological Markov chains, whose theory is part of symbolic dynamics. The C*-algebra construction starts from a matrix A =(A (i,j))i,~ z, Z a finite set, A(i,j)c{0, l}, and where every row and every column of A is non-zero. (That A(i,j)e{O, 1} is assumed for convenience only. All constructions and results extend to matrices with entries in 2~+. We comment on this in Remark 2.18.) A C*-algebra 6~ A is then generated by partial isometries Si~O(i~X ) that act on a Hilbert space in such a way that their support projections Qi=S*S~ and their range projections P~ =SIS* satisfy the relations
1,042 citations
TL;DR: In this article, the authors proposed a standardization with respect to grain size effects, commonly achieved by analyzing the sieve fraction <63μm, which is used to pin point major sources of metal pollution and to estimate the toxicity potential of dredged materials.
Abstract: Sediment analyses are used to pin‐point major sources of metal pollution and to estimate the toxicity potential of dredged materials on agricultural land. For source assessments (Part I of the present review) standardization is needed with respect to grain size effects, commonly achieved by analyzing the sieve fraction <63μm. Further aspects include sampling methods, evaluation of background data and extent of anthropogenic metal enrichment.
530 citations
TL;DR: A survey and discussion of the various approaches which can be found in this literature is presented in this article. And a special effort is made to present an integrated view of the real resource and financial aspect: of banking activities.
468 citations
01 Nov 1980
TL;DR: In this article, a simplified scheme composed of two major extraction steps (acidified hydroxylamine and hydrogen peroxide) is proposed to determine the chemical associations of heavy metals with specific sedimentary phases, whereby the potential, availability of toxic compounds for biological uptake may eventually be estimated.
Abstract: Sequential extraction techniques are used to determine the chemical associations of heavy metals with specific, sedimentary phases, whereby the potential, availability of toxic compounds for biological uptake may eventually be estimated. The importance of such investigations in the classification of dredged materials is rapidly increasing. As in the case for the reduction of grain size effects (see Part I of the present review) a methodological standardization appears to be presently of special import. Available methods are discussed and a simplified scheme composed of two major extraction steps (acidified hydroxylamine and hydrogen peroxide) is proposed.
387 citations
TL;DR: In this paper, the average moments of the eigenfunctions of a particle in a random potential are considered near the mobility edge, and the exponents of the power laws are given in ane-expansion in one-loop order for ad=2+e dimensional system.
Abstract: The averaged moments of the eigenfunctions (including the inverse participation ratio) of a particle in a random potential are considered near the mobility edge. The exponents of the power laws are given in ane-expansion in one-loop order for ad=2+e dimensional system. The calculation is based on a recent formulation of the mobility edge problem which maps it onto a model of interacting matrices.
361 citations
TL;DR: In this paper, an individual barium ion, continuously observed by laser fluorescence, has been isolated in a Paul rf quadrupole trap at room temperature and its image has been reduced in thickness to 2 εm in the object plane, the diffraction limit.
Abstract: An individual barium ion, continuously observed by laser fluorescence, has been isolated in a Paul rf quadrupole trap at room temperature. By optical sideband cooling its microscopically measured image has been reduced in thickness to \ensuremath{\sim} 2 \ensuremath{\mu}m in the object plane, the diffraction limit. Estimated ion temperatures reached are ${T}_{i}\ensuremath{\simeq}10 \mathrm{to} l36$ mK. With cooling, the ion could be held indefinitely, without cooling \ensuremath{\sim} 30 s. In the future the technique seems capable of attaining kinetic temperatures \ensuremath{\sim} ${10}^{\ensuremath{-}8}$ K, much lower than realized so far by other means, with corresponding far-reaching implications.
344 citations
297 citations
TL;DR: In this article, a Lagrangian formulation of the gauge invariant n-orbital model for disordered electronic systems was given, without use of diagrams, and it identifies the previously discussed n→∞ limit as the saddle-point approximation of the Lagrangians formulation.
Abstract: We give a Lagrange formulation of the gauge invariantn-orbital model for disordered electronic systems recently introduced by Wegner. The derivation proceeds analytically without use of diagrams, and it identifies the previously discussedn→∞ limit as the saddle-point approximation of the Lagrangian formulation. We discover that the Lagrangian model crucially depends on the position with respect to the real axis of the energies involved. If the energies occur on both sides of the real axis as is the case in the calculation of the conductivity, then the order parameter field takes values in a set of complex non-hermitean matrices. If all energies are on the same side of the real axis then a hermitean matrix model emerges. This difference reflects a difference in the symmetries. Whereas in the latter case normal unitary symmetry holds, the symmetry in the former case is of hyperbolic nature. The corresponding symmetry group is not compact and this might be a source of singularities also in the region of localized states. Eliminating massive modes in tree approximation we derive an effective Lagrangian for the Goldstone modes. The structure of this Lagrangian resembles the non-linear σ-model and is a very general consequence of broken isotropic symmetry. We also consider the first correction to the tree approximation which is related to the invariant measure of the generalized non-linear σ-model.
284 citations
TL;DR: In this article, a critical review of all the data produced at the ISR on proton-proton elastic scattering and total cross sections is presented, which is used to compute the impact parameter distribution of the inelastic overlap integral.
236 citations
TL;DR: An electronic Hamiltonian appropriate for describing core-hole processes is derived and its properties are discussed in this article, where a many-body theory is presented, and a useful linked-cluster theorem is proven.
Abstract: An electronic Hamiltonian appropriate for describing core-hole processes is derived and its properties are discussed. Based on this Hamiltonian a many-body theory is presented, and a useful linked-cluster theorem is proven. A distinction between relaxation and correlation terms can be made in each order of the perturbation expansion. Under certain well-defined conditions the core-ionization process can be visualized as a Franck-Condon transition between two multidimensional potential-energy surfaces in an abstract bosonic space. The corresponding approximation, the boson approximation, is discussed and applied to the water molecule.
235 citations
TL;DR: In this paper, the topological distribution of charged and neutral hadrons from the reaction e+e− → multihadrons is studied at √s of about 30 GeV, and an excess of planar events is observed at a rate which cannot be explained by statistical fluctuations in the standard two-jet process.
TL;DR: GM1 ganglioside is detected on growing parallel fibers in situ and neurites in vitro but not on adult axons, suggesting differential localization at a later stage of development.
TL;DR: The parallel oriented cellulose microfibrils of the bristles of Canthosphaera zachariasi show difluorescence after staining with the fluorochrome calcofluor white ST, which is adsorbed oriented parallel to the microfibillar longitudinal axis.
Abstract: The parallel oriented cellulose microfibrils of the bristles ofAcanthosphaera zachariasi show difluorescence after staining with the fluorochrome calcofluor white ST This dye thus is adsorbed oriented parallel to the microfibrillar longitudinal axis
TL;DR: Results indicate that blood transfusion-induced suppression of cell-mediated immunity might be caused by an unspecific suppressor cell, and preliminary results show autologous and allogeneic MLR suppression when mitomycin-C treated patient cells taken after transfusion are added.
TL;DR: Three peroxidase isoenzyme-groups found in cell walls of tobacco were tested for their capacity to form H2O2 and Isoenzyme-group GI showed the highest Kapp-value, i.e., maximal H1O2-formation was received for group GIII which is ionically bound to the cell wall, while GI yields maximal polymerization rates for coniferyl- and p-coumarylalcohol.
Abstract: Three peroxidase isoenzyme-groups found in cell walls of tobacco were tested for their capacity to form H2O2. Isoenzyme-group GI, located only in cell walls (GII and GIII are also found in protoplasts) showed the highest Kapp-value for H2O2-formation. The lowest Kapp-value, i.e., maximal H2O2-formation was received for group GIII which is ionically bound to the cell wall. As shown before, GI yields maximal polymerization rates for coniferyl- and p-coumarylalcohol. These facts indicate that each of the peroxidase isoenzyme groups of the cell wall is involved with different catalytic functions within the same pathways of H2O2-formation and succeeding lignification. H2O2-formation catalyzed by all 3 groups was increased by very low concentrations of Mn2+-ions. The required amount of Mn2+ leading to maximal stimulation was in each case dependent on the basic rate of H2O2-formation. Maximal stimulation of H2O2-formation by phenolic compounds was achieved by coniferylalcohol at a concentration of 10-4M for all groups. Stimulation by p-coumaryl-and by sinapylalcohol was not as significant.
TL;DR: The results indicate that functionally separate descending inhibitory systems are activated by stimulation of PAG and LRF, and that descending inhibition is generated at sites throughout the mediolateral extent of the midbrain.
Abstract: 1. The inhibitory effects of electrical stimulation in midbrain periaqueductal gray (PAG) and lateral reticular formation (LRF) on spinal dorsal horn neuronal responses to noxious skin heating were...
TL;DR: In this paper, the authors used the hybridoma technique originally developed by Kohler and Milstein (1975) to establish 755 permanent lymphoid cell lines using the radioimmunoassay.
Abstract: Total nuclear protein from the embryonic D. melanogaster cell line Kc and crude hydroxyapatite fractions thereof were used for immunization of mice. From the spleen cells of these mice we established 755 permanent lymphoid cell lines using the hybridoma technique originally developed by Kohler and Milstein (1975). Radioimmunoassay showed 455 of these cell lines secreted antibodies which bound to component(s) contained in the antigen mixtures used for immunization. Screening of 311 cell lines using indirect immunofluorescence revealed 58 lines whose antibodies showed a highly selective staining pattern on polytene chromosomes from the salivary glands of D. melanogaster third instar larvae. Eight of these cell lines were cloned and further characterized. We were able to order the staining patterns into three distinct classes based on the staining behaviour of the monoclonal antibodies: staining of active regions, staining of phase dark bands or staining of most interbands. The molecular weight of those antigens against which the monoclonal antibodies were directed was determined in SDS polyacrylamide gels.
TL;DR: The interrelationship between the peripheral cytoplasm and the nucleus and the role of microtubules in maintaining and reestablishing cell polarity are discussed.
Abstract: In the caulonema tip cells of Funaria hygrometrica, chloroplasts, mitochondria, and dictyosomes have differences in structure which are determined by cell polarity. In contrast to the slowly growing chloronema tip cells the apical cell of the caulonema contains a tip body. Colchicine stops tip growth; it causes the formation of subapical cell protrusions, redistribution of the plastids, and a loss of their polar differentiation. Cytochalasin B inhibits growth and affects the position of cell organelles. After treatment with ionophore A23 187, growth is slower and shorter and wider cells are formed. D2O causes a transient reversion of organelle distribution but premitotic nuclei are not dislocated. In some tip cells the reversion of polarity persists; they continue to grow with a new tip at their base. During centrifugation, colchicine has only a slight influence on the stability of organelle anchorage. The former polar organization of most cells is restored within a few hours after centrifugation, and the cells resume normal growth. In premitotic cells the nucleus and other organelles cannot be retransported, they often continue to grow with reversed polarity. Colchicine retards the redistribution of organelles generally and increases the number of cells that form a basal outgrowth. The interrelationship between the peripheral cytoplasm and the nucleus and the role of microtubules in maintaining and reestablishing cell polarity are discussed.
TL;DR: In this paper, the mean annual rates of tritium input into the ocean averaged over 5° latitude bands are presented for the period 1952-1975, for the major oceans, by means of a hydrological model.
TL;DR: In this article, sediment cores from the central North Pacific were analyzed for 232Th, 231Pa and230Th activities, and for organic carbon contents to establish Late Quaternary sedimentation rates and organic carbon decomposition rates during early diagenesis.
TL;DR: The absence of antibodies directed against proteins possibly contaminating the antigens used for immunization allowed us to identify RNA polymerase unequivocally in interbands and puffs of polytene chromosomes.
Abstract: Monoclonal antibodies were raised against purified RNA polymerase II ( or B) from Drosophila melanogaster. The antibody produced by one hybridoma cell clone was found to be directed against the two large subunits of the enzyme. The absence of antibodies directed against proteins possibly contaminating the antigens used for immunization allowed us to identify RNA polymerase unequivocally in interbands and puffs of polytene chromosomes. Within a single heat shock puff (87C1) RNA polymerase was found to be clustered in two separate areas suggesting two distinct regions of RNA polymerase activity in this puff.
TL;DR: In ghosts of hamster adipocytes, the regulation of adenylate cyclase by prostaglandins, α-adrenergic agonists and nicotinic acid was studied, suggesting that an α2 of receptors is involved in this catecholamine-induced inhibition.
Abstract: In ghosts of hamster adipocytes, the regulation of adenylate cyclase (ATP: pyrophosphate lyase, cyclizing; EC 4.6.1.1) activity by prostaglandins, α-adrenergic agonists and nicotinic acid was studied. These three classes of antilipolytic agents caused adenylate cyclase inhibition without an apparent lag phase. Maximal inhibitions observed ranged between about 45% (by α-adrenergic agonists) and 60% (by prostaglandins and nicotinic acid). The order of potency for the inhibitory prostaglandins (PG) was PGE1 ≧ PGE2>PGF2α≅PGI2>PGD2>6-keto PGF1α. The IC50 values obtained were about 0.007, 0.06, 0.3 and 1 μM for PGE1, PGF2α, PGD2 and 6-keto PGF1α, respectively. α-Adrenergic agonists, studied in the presence of the β-adrenergic blocking agent, propranolol (30 μM), inhibited the fat cell enzyme with the order of potency (1)-adrenaline > (1)-α-methylnoradrenaline ≅ (1)-noradrenaline > clonidine ≅ tetryzoline > (1)-phenylephrine. The IC50 values obtained for (1)-adrenaline and (1)-noradrenaline were about 3 and 10 μM, respectively. The inhibitory effect of (1)-adrenaline was blocked by the α-adrenergic antagonists with the potency order yohimbine ≅ phentolamine > prazosin. These findings suggest that an α2 of receptors is involved in this catecholamine-induced inhibition. Nicotinic acid (10 μM) reduced adenylate cyclase activity by about 60% with half-maximal effectiveness at about 0.6 μM. The nicotinic acid derivatives, nicotinamide, β-pyridylcarbinol and NAD (up to 100 μM), had no effect on enzyme activity.
TL;DR: Renin-like immunoreactivity could be demonstrated in the nuclei paraventricularis, periventricularIS and supraopticus of the hypothalamus and in the cerebellar cortex of rats and mice, consistent with the assumption of an endogenous angiotensin-forming system in the brain.
TL;DR: In this paper, the same authors showed that CH2Cl2(1), (2), (3), (4), (5) and (6) compounds of stoichiometry (pe)2(PF6)1.1 × 0.6 THF, (pe(2(AsF6),1.5×0.5 THF), and (pe3(SbF6)2× 0.75 CH2CL2) have been obtained as crystalline samples by electrochemical deposition from CH 2Cl2 [(1, (2
Abstract: Compounds of stoichiometry (pe)2(PF6)1.1 × 0.8CH2Cl2(1) (pe = perylene), (pe)2(AsF6)1.1 × 0.7 CH2Cl2 (2), (pe)2(PF6)1.4 × 0.6 THF (3), (pe)2(AsF6)1.5 × 0.5 THF (4) and (pe)3(SbF6)2 × 0.75 CH2Cl2 (5) have been obtained as crystalline samples by electrochemical deposition from CH2Cl2 [(1), (2) and (5)] or from THF [(3) and (4)] solutions of perylene, containing the appropriate counterion. The three compounds (1)-(3) crystallize in isomorphous orthorhombic lattices. (1) forms black needles: space group Pnmn with a = 4.285 A, b = 12.915 A and c = 14.033 A, z = 1. (2) gives black needles, orthorhombic space group Pnmn with a = 4.294 A, b = 13.077 A, and c = 14.132 A, z = 1. The structures of (1) and (2) were solved by direct methods and refined by least squares to final R = 0.148 and R = 0.088 based on 476 and 322 observed reflections. The perylene forms segregated stacks in direction of the a-axis with interplanar distances of 3.40 A and an angle of 37.7° between the bc-plane and the perylene. The ch...
TL;DR: Hinweise für eine intravasale Gerinnung fanden sich — im Gegensatz zu Angaben der Literatur — in eigenen Untersuchungen nur selten, was auf eine erworbene Funktionsstörung hinweist geringfügig verkürzt.
Abstract: The risk of thromboembolic complications in patients with the nephrotic syndrome (NS) is higher than in any other condition encountered in internal medicine. Such thromboembolic complications comprise venous thromboses (calf, thigh, renal vein) with or without pulmonary embolism and arterial thromboses (coronary thromboses, cerebral artery thromboses, peripheral arterial thromboses). Several defects of the plasmatic coagulation system, fibrinolysis and platelet function had been recognized in the nephrotic syndrome. Increased hepatic synthesis causes a rise of coagulation factors, I, II, VII, VIII, X and increased renal loss causes lowering of the plasma concentration of antithrombin III concentration. There is little evidence for DIC. Plasminogen concentration is diminished, whereas total antiplasmin activity is increased. Low alpha-1-antitrypsin concentration secondary to renal loss is outweighed by increased concentrations of other inhibitors especially alpha-2-macroglobulin and alpha-2-antiplasmin. The common presence of material in the urine reacting as fibrin degradation products with passive hemagglutination techniques appears to be proteolytically degraded fibrinogen excreted as a result of non-selective glomerular proteinuria. Platelet counts are normal or slightly elevated and platelet survival time is slightly, decreased. Definite abnormalities of spontaneous aggregation and ADP- or collagen-induced aggregation are demonstrable. Furthermore, arachidonic acid induced platelet aggregation and malondialdehyde formation by platelets of NS patients are increased. Addition of albumin to platelets of NS patients normalises platelet aggregation. This finding points to some acquired defect of platelet function.
TL;DR: The results suggest an involvement of SP-innervation in the regulation of coronary blood flow, and substance P-immunoreactive nerve fibers and varicosities were identified in the adventitial layers of the aorta, the pulmonary trunk and the coronary arteries and veins in the guinea pig heart.
TL;DR: Single-stranded DNA vectors were constructed in vitro by insertion of various DNA fragments into the Intergenic Region of the single-Stranded DNA phage fd by introducing into the phage genome unique cleavage sites for restriction nucleases, suited for sticky joining in cloning experiments.
Abstract: Single-stranded DNA vectors were constructed in vitro by insertion of various DNA fragments into the Intergenic Region of the single-stranded DNA phage fd. These inserts introduce into the phage genome unique cleavage sites for restriction nucleases which are suited for sticky joining in cloning experiments. Since these sites are usually located within genes coding for antibiotic resistance, inactivation of a resistance gene by insertion can be used as a marker for the successful cloning of a DNA fragment. Resistance genes also allow to select for recombinant DNA phages and to minimize the loss of DNA inserts which otherwise becomes significant above an insert size of about one kb. Cloning of several DNA fragments is described and strand separation of double-stranded DNA fragments by means of cloning into fd DNA is given as an example for application of single-stranded DNA vectors.