Showing papers by "Heidelberg University published in 1979"
01 Jan 1979
TL;DR: For the nonparametric estimation of regression functions with a one-dimensional design parameter, a new kernel estimate is defined and shown to be superior to the one introduced by Priestley and Chao (1972) as discussed by the authors.
Abstract: For the nonparametric estimation of regression functions with a one-dimensional design parameter, a new kernel estimate is defined and shown to be superior to the one introduced by Priestley and Chao (1972). The results are not restricted to positive kernels, but extend to classes of kernels satisfying certain moment conditions. An asymptotically valid solution for the boundary problem, arising for non-circular models, is found, and this allows the derivation of the asymptotic integrated mean square error. As a special case we obtain the same rates of convergence as for splines. For two optimality criteria (minimum variance, minimum mean square error) higher order kernels are explicitly tabulated.
834 citations
TL;DR: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus.
Abstract: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus. The sequence of the core antigen shows it to be a DNA binding protein. The core antigen gene is expressed in Escherichia coli and when injected into rabbits the bacterial product induces antibodies which react with core antigen isolated from human sources.
566 citations
TL;DR: An apparently overlooked symmetry of the disordered electron problem is derived in this article, which yields the well-known Ward-identity connecting the one and two-particle Green's function and conjecture that the critical behaviour near the mobility edge coincides with that of interacting matrices which have two different eigenvalues of multiplicity zero (due to replicas).
Abstract: An apparently overlooked symmetry of the disordered electron problem is derived. It yields the well-known Ward-identity connecting the one- and two-particle Green's function. This symmetry and the apparent shortrange behaviour of the averaged one-particle Green's function are used to conjecture that the critical behaviour near the mobility edge coincides with that of interacting matrices which have two different eigenvalues of multiplicity zero (due to replicas). As a consequence the exponents of the d.c. conductivity is expected to approach 1 for real matrices and 1/2 for complex matrices as the dimensionality of the system approaches two from above. In two dimensions no metallic conductivity is expected.
442 citations
TL;DR: The genetic basis of retinoblastoma is reviewed and the alternative possibility is suggested that in the nonhereditary variant a single mutational step—possibly a small chromosome aberration—could be enough to produce a tumor.
Abstract: The first well-documented observation of retinoblastoma (Rb) in several members of one family was published by Lerche (1821). Four of seven siblings, children of healthy parents, were affected. At that time, the tumor almost invariably led to death during infancy or early childhood. The first pedigrees with transmission through two or more generations were observed only after enucleation of the affected eye had been introduced by von Graefe. More recently, the mode of inheritance has been identified as autosomal dominant with incomplete penetrance; Fig. 13.1 shows a typical pedigree. Unilateral as well as bilateral cases may occur in the same family, and the tumor may even skip one generation. Statistical analysis of many families (see Vogel 1979) led to the conclusion that the penetrance of the dominant gene causing Rb is about 90%; i.e., 90% of heterozygotes will be affected.
407 citations
TL;DR: The location of those neurones in the brain stem that project to the intermediolateral column (ILC) from which preganglionic sympathetic neurones have their origin was studied by the method of retrograde transport of horseradish peroxidase (HRP).
Abstract: The location of those neurones in the brain stem that project to the intermediolateral column (ILC) from which preganglionic sympathetic neurones have their origin was studied by the method of retrograde transport of horseradish peroxidase (HRP). In cats 30--50 nl of a 30% HRP solution was injected into the region of the ILC at T3 or L1 on one side. After a survival period of 72 h the lower brain stem from C1 to the inferior colliculi was sectioned and prepared for histological study under brightfield illumination. Neurones stained with exogenous HRP were found in three regions: (a) in the ipsilateral, dorsomedial part of the nucleus of the solitary tract (NTS) (43% of all labeled neurones), in the cranial part of the NTS, and also on the contralateral side (7%); (b) in the ventrolateral reticular formation beginning at the level of the obex up to 8 mm cranial to the obex (25% ipsilateral, 3% contralateral); and (c) in the ventral part of the raphe nuclei (postpyramidal and inferior central nucleus) from 2 to 9 mm cranial to the obex (22%).
311 citations
TL;DR: The observations did not support the assumption that there exists a specific period for alcohol teratogenicity, and showed a wide spectrum of disorders ranging from severe dysraphic state to craniofacial dysmorphogenesis and palmar crease anomalies.
249 citations
213 citations
TL;DR: A new method for impregnation of biological specimens with thermosetting resins and elastomers is described, which has the advantage that the original relief of the surface is retained.
Abstract: A new method for impregnation of biological specimens with thermosetting resins and elastomers is described. The method has the advantage that the original relief of the surface is retained. The impregnation is carried out by utilizing the difference between the high vapor tension of the intermedium (e.g., methylene chloride) and the low vapor tension of the solution to be polymerized. After impregnation, the specimen is subject to polymerization conditions without surrounding embedding material. The optical and mechanical properties can be selected by proper choice from various kinds of resins and different procedures, for example, by complete or incomplete impregnation. Acrylic resins, polyester resins, epoxy resins, polyurethanes and silicone rubber have been found suitable for the method. Excellent results have been obtained using transparent silicone rubber since after treatment the specimens are still flexible and resilient, and have retained their natural appearance.
193 citations
TL;DR: The data indicate that cholinergic agonists inhibit cardiac adenylate cyclase by a process that requires (the hydrolyzable) GTP and involves sodium ions.
Abstract: In membrane-containing particles of rabbit myocardium, inhibition of adenylate cyclase (EC 4.6.1.1) by cholinergic agonists was studied. The cholinergic agonists, in the potency order oxotremorine > acetylcholine > carbachol, reduced basal adenylate cyclase activity with half-maximal effects at about 0.3, 1 and 3 μM, respectively; maximal inhibition observed was about 40%. The enzyme inhibition occurred without apparent lag phase and was reversed by the muscarinic cholinergic antagonist, atropine, which finding indicates that muscarinic cholinergic receptors are involved in this process.
167 citations
TL;DR: The demonstration of met-enkephalin-like immunoreactivity supports the concept that the Merkel cell is a member of the paraneuronal system and a potential neuroreceptor cell.
Abstract: The Merkel cells from sinus hair follicles of rats were investigated by immunohistochemistry using different antisera against neuropeptides and gastroenteropancreatic (GEP)-hormones. For the first time it has been demonstrated that Merkel cells exhibit an immunoreactivity towards metenkephalin (methionine-enkephalin). The met-enkephalin immunoreactivity was restricted to Merkel cells and was not found in associated nerve axons or terminals. Denervation of Merkel cells did not affect the met-enkephalin immunoreactivity. Antisera against leu-enkephalin (leucine-enkephalin) and other polypeptides did not produce an immunoreaction. The demonstration of met-enkephalin-like immunoreactivity supports the concept that the Merkel cell is a member of the paraneuronal system and a potential neuroreceptor cell.
146 citations
TL;DR: The results are interpreted as evidence for a general role of a calcium gradient in tip growth and for a cytoplasmic localization of the gradient in Acetabularia.
Abstract: With chlorotetracycline (CTC)-fluorescence a tip-to-base Ca2+ gradient is visualized in all tested, tip-growing plant cells: pollen tubes of Lilium longiflorum, root hairs of Lepidium sativum, moss caulonema of Funaria hygrometrica, fungal hyphae of Achlya and in the alga Acetabularia mediterranea. The fluorescence gradients in the different species vary in intensity and extension. Sometimes a punctate mobile CTC-fluorescence, in the size range of mitochondria, is observed. Bursting cells lose their fluorescence rapidly, indicating a cytoplasmic localization of the gradient. Only in Acetabularia is the wall also fluorescent with CTC. The results are interpreted as evidence for a general role of a calcium gradient in tip growth.
TL;DR: In this article, the neutrino energy range 30-200 GeV was investigated and the results were in agreement with the expectations of the quark parton model and QCD.
Abstract: We present results on charged current inclusive neutrino and antineutrino scattering in the neutrino energy range 30–200 GeV. The results include a) total cross-sections; b)y distributions; c) structure functions; and d) scaling violations observed in the structure functions. The results, as well as their comparison with the results of electron and muon inclusive scattering, are in agreement with the expectations of the quark parton model and QCD.
TL;DR: In this article, the authors measured the total cross section in units of the point-like e+e− → μ+μ- cross section at the highest PETRA energies and found that the observed average multiplicity, together with existing low energy data, indicate a rapid increase in multiplicity with increasing energy.
TL;DR: The findings support the following ideas on the arrangement of interphase chromosome: (1) Decondensed interphase chromosomes may occupy rather compact territories and (2) Chromosomes do not necessarily exhibit a close and permanent association with their respective homologues.
TL;DR: In this paper, an estimate of the distances of Riemannian manifolds by the distance of their boundary values was proved using a maximum principle. But it was not shown that the maximum principle can be used to estimate the distance between the norm of Jacobi fields along harmonic maps.
Abstract: Let M, N be Riemannian manifolds and let f1, f2: M→N be harmonic maps. Using a maximum principle, an estimate of the distances of these maps by the distances of their boundary values will be proved. Corresponding estimates will be stated for the norm of Jacobi fields along harmonic maps, and for the distances of solutions of the heat equation.
TL;DR: The low-voltage (N) group scored high in intelligence tests, especially in spatial orientation and personality scores revealed this group as ‘normal’, extravert, group-dependent, and not very energetic.
Abstract: Interpretation of the results from psychological examinations of 298 probands with inherited EEG variants requires (1) critical evaluation of previous literature on psychological EEG correlates, (2) knowledge of the main concepts and experimental approaches for elucidating the basic mechanisms of EEG rhythms, (3) discussion of previous attempts to link psychological variation in human populations with corresponding variation in brain function, and (4) interpretation of results from considerations at these three levels with the data from out own study.
TL;DR: In this article, absolute differential cross sections have been obtained using the split-field magnet detector facility (SFM) at the five standard energies for integrated luminosities ranging from 0.3 to 4.9 (pb) −1.
TL;DR: In this article, a theoretical approach to the construction of extrapolation methods for systems of the kind is presented, where the discretization schemes are required to be exact and to contain only solutions in the nullspace of the general linear differential operator of orderk.
Abstract: The paper presents a theoretical approach to the construction of extrapolation methods for systems of the kind.
$$L[y] = \varepsilon f(t,y,),$$
whereL is a general linear differential operator of orderk. For e=0, the discretization schemes are required to beexact and to contain only solutions in the nullspace ofL. For e≠0, the paper studies the construction of methods that permitquadratic extrapolation. In the special casek=2, a new two-step method is obtained that applies to systems of the type
$$y'' + Ay = \varepsilon f(t,y,y')$$
whereA is a real, symmetric, positive semi-definite matrix. This algorithm might be of use inregular celestial mechanics-apart from any other possible applications.
TL;DR: In this paper, a small circular wind-water tunnel was used to study the effect of wind speed on gas exchange and momentum transfer in the presence of rough waves, and the experiments clearly showed the enhancement of air-water exchange processes by waves.
Abstract: Gas exchange and momentum transfer have been studied by means of a small circular wind-water tunnel. Gas transfer velocity and friction velocity first grow linearly with wind speed. At a critical wind speed, with the onset of rough waves, both increase abruptly. The experiments clearly show the enhancement of air-water exchange processes by waves. Experimental conditions were varied-nitrogen/carbon dioxide atmosphere, temperature, circulation of water unconfined/confined by a dam-and found to influence gas exchange. This, and the differing results of various authors demonstrate that gas exchange is not a function of wind speed alone, nor of friction velocity, but that further parameters, such as wave spectra, have to be considered as well. DOI: 10.1111/j.2153-3490.1979.tb00911.x
TL;DR: The effects of the calcium inonophore A 23187 on growing pollen tubes of Lilium longiflorum Thunb.
Abstract: The effects of the calcium inonophore A 23187 on growing pollen tubes of Lilium longiflorum Thunb. cv. Ace were investigated with the light and electron microscope. Tip growth is slowed down and stopped within 20 min after application of 5x10-5 M ionophore A 23187. The main effects are the disappearance of the clear zone at the pollen tube tip and a thickening of the cell wall at the tip and at the pollen tube flanks. This effect on cell wall formation is confirmed under the electron microscope: The vesicular zone in treated pollen tubes is reduced, numerous vesicular contents are irregularly integrated in the pollen tube wall not only in the tip, but over a long distance of the pollen tube wall. In addition, effects on mitochondria and dictyosomes are observed. These results are interpreted as a disorientation of the Ca2+-based orientation mechanism of exocytosis after equilibration of the Ca2+-gradient
TL;DR: The theory of Bayesian games, as developped by W. Boge, is axiomatically treated in this article and a direct access to the system of complete reflections is shown.
Abstract: The theory of Bayesian games, as developped by W. Boge, is axiomatically treated. A direct access to the system of complete reflections is shown. Solutions for these games are defined and characterizations for their existence are given.
TL;DR: PAGS resulted in a decrease in the slope of the curve plotting discharge against temperature, without altering the threshold, and inhibition of the heat-evoked discharges rarely outlasted the PAGS.
Abstract: 1. Discharges of lumbar dorsal horn neurons were evoked by noxious radiant skin heating, and inhibition of the heat-evoked responses by stimulation of the mesencephalic periaqueductal gray was investigated in N2O-anesthetized cats. 2. Thirty-seven units selected on the basis of receiving afferent C-fiber input from the posterior tibial and/or superficial peroneal nerves responded vigorously to 50 degrees C heating of the plantar surface of the ipsilateral hindpaw. All discharges were inhibited by periaqueductal gray stimulation (PAGS) at current strengths of 300--900 microA; the mean threshold for inhibition was 167 microamperemeter. The mean frequency of the inhibited discharge was 39% of the control response. 3. Effective PAGS sites were distributed throughout the ventral PAG bilaterally. Stimulus current-distance estimates indicate that small (0.5--1.2 mm diameter) volumes of tissue within the PAG were stimulated. 4. A monotonic relationship between temperature and unitary discharge was found for skin heating from threshold to about 50 degrees C. PAGS resulted in a decrease in the slope of the curve plotting discharge against temperature, without altering the threshold. 5. Inhibition of the heat-evoked discharges rarely outlasted the PAGS. 6. Possible neural substrates for descending inhibition and correlates with neural mechanisms of analgesia are discussed.
TL;DR: Investigating the effect of administration of several pterins on serum phenylalanine concentration (Phe) and urinary pterin excretion was investigated in two patients with atypical phenylketonuria (PKU) and demonstrates that BH4, BH2, L -sepiapterin and Neh4, in admixture with ascorbic acid, can be absorbed easily upon oral administration.
TL;DR: In this paper, the 1 H-nmr signal of the equatorially orientated protons at C-3 of N-acetyl-D-neuraminic acid and its derivatives shows a quite characteristic dependence on the anomeric configurations.
TL;DR: In hamster fat cells, the influence of the cu-adrenergic component of epinephrine and of PGEr on adenylate cyclase is studied and it is reported here that GTP and Nd are required for the inhibition of the enzyme by these hormonal factors.
TL;DR: In this article, a numerically applicable stepsize control for discrete continuation methods of orderp is derived on a theoretical basis, and the theoretical results and the performance of the proposed algorithm are invariant under affine transformation of the nonlinear system to be solved.
Abstract: A numerically applicable stepsize control for discrete continuation methods of orderp is derived on a theoretical basis. Both the theoretical results and the performance of the proposed algorithm are invariant under affine transformation of the nonlinear system to be solved. The efficiency and reliability of the method is demonstrated by solving three real life two-point boundary value problems using multiple shooting techniques. In two of the examples bifurcations occur and are significantly marked by sharp changes in the stepsize estimates.
TL;DR: Throttling of freshwater inputs into the meromictic Dead Sea weakened the long-term stability of the water column, and complete overturn finally took place during the winter of 1978-1979.
Abstract: Throttling of freshwater inputs into the meromictic Dead Sea weakened the long-term stability of the water column. Between 1975 and 1978 successive deepenings of the pycnocline from 70 meters to beyond 200 meters were recorded. Complete overturn finally took place during the winter of 1978-1979. This unique process was accompanied by changes in the geochemistry of several components.
TL;DR: The position of the nick in the nucleotide sequence of the fd genome is reported, which shows strand specificity of nicking and the viral strand was cleaved into a full length linear form, whereas the complementary strand remained circular.
Abstract: DOUBLE-STRAND DNA replication of small single-stranded bacteriophages such as ΦX174 and filamentous phage fd is initiated by highly specific endonucleases. This was demonstrated in vitro with the isolation of ΦX cisA protein1 and more recently with that of fd gene II-protein2. Both endonucleases produce one single-strand break in the viral strand of superhelical RFI providing an origin for double-strand (ds) DNA replication3,4. For gene II-protein the strand specificity of nicking was demonstrated by cleavage of asymmetrically labelled fd RFI (viral strand 32P-labelled, complementary strand 3H-labelled) and subsequent alkaline sucrose sedimentation. As a result the viral strand was cleaved into a full length linear form, whereas the complementary strand remained circular (T.F.M. and K.G., submitted). Here we report the position of the nick in the nucleotide sequence of the fd genome.
TL;DR: In this article, the average natural uranium content of world rivers, for 35% of the water input to the ocean, was calculated to be µg l−1, which indicates that a low uranium content is due to low HCO−3 contents and not to lower contamination levels.
Abstract: α-SPECTROMETRIC uranium isotopes analyses on groundwater samples from the highly fertilised Handschuhsheimer Feld area in Heidelberg suggest that the uranium content of the groundwater is primarily of natural origin; uranium derived from phosphate fertilisers is adsorbed on the uppermost soil layers and the uranium content of the water is correlated to the HCO−3 content. A similar relationship between uranium and HCO−3 also applies for world rivers and lakes. We show here that this indicates that a low uranium content is due to low HCO−3 contents and not to lower contamination levels. On the basis of this correlation the average natural uranium content of world rivers, for 35% of the water input to the ocean, was calculated to be µg l−1.
TL;DR: In this paper, a mechanism for the first hydroxo-bridge cleavage of the triply-bridged complex was proposed, involving cis-trans isomerization of 2 as the rate determining step.
Abstract: Das zweikernige Tri-μ-hydroxo-bis[(1,4,7-triazacyclononan)cobalt(III)]-Kation (1) wird dargestellt. In saurer Losung entsteht daraus das trans-Diaqua-di-μ-hydroxo-bis[(1,4,7-triazacyclononan)cobalt(III)]-Kation (2), dessen Struktur rontgenographisch bestimmt wurde. Die Kinetik der Gleichgewichtseinstellung der Spaltung der ersten OH-Brucke von 1 wurde gemessen. Es wird ein Mechanismus vorgeschlagen. Bei dem die cis-trans-Isomerisierung von 2 den geschwindigkeitsbestimmenden Schritt darstellt, und der alle(auch fruhere) experimentelle Daten der OH-Bruckenspaltung sowie die Bildung von Tri-μ-hydroxo-bis[amincobalt(III)]-Komplexen widerspruchsfrei deutet.
Novel μ-Hydroxo-Transition Metal Complexes, I. Preparation and Crystal Structure of the trans-Diaqua-di-μ-hydroxo-bis[(1,4,7-triazacyclononane)cobalt(III)]Cation; Kinetics and Mechanism of its Formation
The binuclear tri-μ-hydroxo-bis[(1,4,7-triazacyclononane)cobalt(III)] cation (1) is prepared. In acidic solutions 1 forms the trans-diaqua-μ-hydroxo-bis[(1,4,7-triazacyclononane)cobalt(III)] cation (2), the structure of which has been established by single crystal X-ray diffraction. The equilibration kinetics of the first hydroxo-bridge cleavage of the triply-bridged complex 1 have been studied. A mechanism is proposed involving cis-trans isomerization of 2 as the rate determining step. The mechanism is consistent with all (including previously published) experimental data for the OH-bridge cleavage processes of tri-μ-hydroxo-bis[aminecobalt(III)] complexes.