Showing papers by "Karlsruhe Institute of Technology published in 1991"
TL;DR: Using a monoclonal antibody raised against a surface glycoprotein of the metastasizing rat pancreatic carcinoma cell line BSp73ASML, cDNA clones have been isolated that encode glycoproteins with partial homology to CD44, a presumed adhesion molecule.
1,703 citations
TL;DR: Experimental techniques commonly used for high strain-rate testing of concrete in compression, together with the methods used for measurement and recording of stress and strain, are critically assessed in the first part of this paper as discussed by the authors.
Abstract: Experimental techniques commonly used for high strain-rate testing of concrete in compression, together with the methods used for measurement and recording of stress and strain, are critically assessed in the first part of this paper. The physical capability of each loading method is discussed and some consideration is given to the definitions used for specifying the loading rate. The second part reviews the dynamic compressive strength (mostly uniaxial rather than bi- or triaxial) of plain concrete, while in the third part a review on deformation behaviour indicates that uncertainty and disagreement exist concerning changes in axial strain at high strain rates.
1,167 citations
TL;DR: In this paper, the DELPHI Collaboration data was used to show that in the minimal non-supersymmetric standard model with one Higgs doublet a single unification point is excluded by more than 7 standard deviations.
1,114 citations
TL;DR: In this article, a library of Monte Carlo programs for leptonic and semileptonic decays of the τ lepton is presented, which can be easily attached to any Monte Carlo program simulating the production of τ's.
400 citations
TL;DR: Leaves preconditioned in this way could prevent or reduce damage to photosynthetic function caused by short wavelength UV‐B radiation.
Abstract: —
Ultraviolet-B radiation induces the accumulation of UV-absorbing pigments of the flavonoid type in the epidermal layer of rye seedlings. The content of pigments identified as isovitexin derivatives was about 4 times higher in leaves preirradiated for up to 24 h with long wavelength UV-B radiation as compared to control plants without any UV-B pretreatment. Leaves preconditioned in this way could prevent or reduce damage to photosynthetic function caused by short wavelength UV-B radiation. Photosynthetic activity monitored by variable fluorescence was reduced in unprotected leaves compared to protected leaves when expressed as a fluorescence decrease ratio value, as quantum yield of photosystem II (Fvm/Fm) or as leaf vitality index (Fm/Fo).
379 citations
TL;DR: The so-called hypoelastic constitutive equations, defined by the equationℸ=h(T, D), are limited by the requirement that h is linear in D.
Abstract: The so-called hypoelastic constitutive equations, defined by the equationℸ=h(T, D), are limited by the requirement thath is linear inD. Dropping this requirement and retaining positive homogeneity of the first degreen inD leads to a broader class of equations which can be calledhypoplastic. Such equations are appropriate to describe the anelastic behaviour of granular materials. Some properties of hypoplastic equations are discussed in this paper including the new notions of yield and bound surfaces which are given a completely different meaning than in classical elastoplasticity. Possiblities to enlarge hypoplasticity towards rate-dependence and more complex intrinsic memory of the material are pointed to.
351 citations
07 Jan 1991
336 citations
TL;DR: In this article, the π0-form factor of the η-meson was determined from its decay modes π+π−π0, π +π−γ and the neutral decay mode γγ.
Abstract: We present measurement of the π0γ*γ, ηγ*γ and η′γ*γ form factors. The π0-form factor is for the first time observed in the space-like region. The transition form factor of the η-meson is determined from its decay modes π+π−π0, π+π−γ and the neutral decay mode γγ. The decay of the η′ is observed in the decay channels ργ, ηπ+π− with η→γγ and in the four charged prong final state stemming from ηπ+π− with the η decaying into π+π−(π0/γ). All form factors agree well with a simple ρ-pole predicted by the vector meson dominance model and also with the QCD inspired Brodsky-Lepage model.
277 citations
TL;DR: In this article, a calibration scheme for accurate spin-echo self-diffusion measurements in liquids is described, and reference data for selfdiffusion coefficients in various liquids and solutions which may serve for calibrating 1H, 2D, 6Li, 7Li, '3C, 19F, 23Na, 3'P, and 133CS self diffusion measurements are reported.
236 citations
TL;DR: In this paper, a higher-resolution and bounded discretization scheme is proposed for calculations of incompressible steady flows with finite-volume methods, which combines a second-order upstream-weighted approximation with the first-order upwind differencing under the control of a convection boundedness criterion.
Abstract: A higher-resolution and bounded discretization scheme is proposed for calculations of incompressible steady flows with finite-volume methods. The scheme combines a second-order upstream-weighted approximation with the first-order upwind differencing under the control of a convection boundedness criterion. It is easy to implement for calculations of multi-dimensional flows, and the resulting finite-difference coefficient matrix is always diagonally dominant. Applications to three test problems, two linear and one non-linear, and comparisons with two commonly used schemes, hybrid upwind/central differencing and QUICK, demonstrate the capability of the method in capturing steep gradients while maintaining the boundedness of solutions.
234 citations
01 Jan 1991
TL;DR: A technique, called ISDN-Mixes, which shows thatUntraceable communication for services like telephony is often considered infeasible in the near future because of bandwidth limitations, but this is not the case.
Abstract: Untraceable communication for services like telephony is often considered infeasible in the near future because of bandwidth limitations. We present a technique, called ISDN-Mixes, which shows that this is not the case.
09 Apr 1991
TL;DR: An algorithm for robot localization using visual landmarks is described, which determines both the correspondence between observed landmarks and a preloaded map, and the location of the robot from those correspondences.
Abstract: An algorithm for robot localization using visual landmarks is described. This algorithm determines both the correspondence between observed landmarks (in this case vertical edges in the environment) and a preloaded map, and the location of the robot from those correspondences. The primary advantages of this algorithm are its use of a single geometric tolerance to describe observation error, its ability to recognize ambiguous sets of correspondences, its ability to compute bounds on the error in localization, and its fast execution. The current version of the algorithm has been implemented and tested on a mobile robot system. In several hundred trials the algorithm has not failed, and computes location accurate to within a centimeter in less than half a second. >
TL;DR: Blue fluorescence emission seems to be caused by substances like the alkaloid berberine and quercetin, while Riboflavine, NADPH and phyllohydroquinoneK1 seem to contribute little to the BF and GF emission as compared to the other plant compounds.
Abstract: The UV-B radiation (e.g. 337 nm) induced blue fluorescence (BF) and red chlorophyll fluorescence spectra (RF) of green leaves from plants with different leaf structure were determined and the possible nature and candidates of the blue fluorescence emission investigated. The blue fluorescence BF is characterized by a main maximum in the 450 nm region and in most cases by a second maximum/shoulder in the 530 nm region. The latter has been termed green fluorescence GF. The red chlorophyll fluorescence RF, in turn, exhibits two maxima in the 690 and 730 nm region. In general, the intensity of BF, GF and RF emission is significantly higher in the lower than the upper leaf side. The ratio of BF to RF emission (F450/F690) seems to vary from plant species to plant species. BF and GF emission spectra appear to be a mixed signal composed of the fluorescence emission of several substances of the plant vacuole and cell wall, which may primarily arise in the epidermis. Leaves with removed epidermis and chlorophyll-free leaves, however, still exhibit a BF and GF emission. Candidates for the blue fluorescence emission (λ max near 450 nm) are phenolic substances such as chlorogenic acid, caffeic acid, coumarins (aesculetin, scopoletin), stilbenes (t-stilbene, rhaponticin), the spectra of which are shown. GF emission (λ max near 530 nm) seems to be caused by substances like the alkaloid berberine and quercetin. Riboflavine, NADPH and phyllohydroquinoneK
1 seem to contribute little to the BF and GF emission as compared to the other plant compounds. Purified naturalβ-carotene does not exhibit any blue fluorescence.
TL;DR: It will be shown that the magnitude of persistent currents increases the more that fluctuations in the charge are suppressed, which explains the peculiar role of the Coulomb interactions between electrons and ions which enforces local charge neutrality.
Abstract: It will be shown that the magnitude of persistent currents increases the more that fluctuations in the charge, i.e., in the electron density, are suppressed. This explains the peculiar role of the Coulomb interactions between electrons and ions which enforces local charge neutrality.
TL;DR: In this article, the potentials of so-called linear semi-iterative methods are considered for the approximate solution of linear ill-posed problems and ill conditioned matrix equations, and various direct and converse results are derived to illustrate the properties of this concept.
Abstract: In this paper, the potentials of so-calledlinear semiiterative methods are considered for the approximate solution of linear ill-posed problems and ill conditioned matrix equations. Several efficient two-step methods are presented, most of which have been introduced earlier in the literature. Stipulating certain conditions concerning the smoothness of the solution, a notion of optimal speed of convergence may be formulated. Various direct and converse results are derived to illustrate the properties of this concept.
If the problem's right hand side data are contaminated by noise, semiiterative methods may be used asregularization methods. Assuming optimal rate of convergence of the iteration for the unperturbed problem, the regularized approximations will be of order optimal accuracy.
To derive these results, specific properties of polynomials are used in connection with the basic theory of solving ill-posed problems. Rather recent results onfast decreasing polynomials are applied to answer an open question of Brakhage.
Numerical examples are given including a comparison to the method of conjugate gradients.
TL;DR: In this article, the Yang-Baxter equation is solved in two dimensions giving rise to a two-parameter deformation of GL(2), and the transformation properties of quantum planes are briefly discussed.
Abstract: The Yang-Baxter equation is solved in two dimensions giving rise to a two-parameter deformation ofGL(2). The transformation properties of quantum planes are briefly discussed. Non-central determinant and inverse are constructed. A right-invariant differential calculus is presented and the role of the different deformation parameters investigated. While the corresponding Lie algebra relations are simply deformed, the comultiplication exhibits both quantization parameters.
TL;DR: Two different types of interaction between the radiation used for measurement and the investigated vector fields are discussed and some experimental results are presented showing the reconstruction of flow velocity fields based on ultrasonic time-of-flight measurements.
Abstract: The application of tomography to the reconstruction of vector fields is considered. Two different types of interaction between the radiation used for measurement and the investigated vector fields are discussed. A complete reconstruction of a vector field can only be obtained if measurements based on both types of interaction are available. Otherwise, only curl-free or source-free components of the field can be reconstructed. In the case of nonhomogeneous boundary conditions, additional harmonic field components occur. Some experimental results are presented showing the reconstruction of flow velocity fields based on ultrasonic time-of-flight measurements. >
TL;DR: Genes for respiratory nitrite reduction (denitrification) of Pseudomonas stutzeri are clustered within 7 kbp and structural genes for cytochromes have a signal sequence for protein export.
Journal Article•
TL;DR: The high [Ca2+]i found in the tube tip with fura-2 seems to indicate the real Ca2+ concentration and is probably responsible for vesicle fusion, fragmentation of actin filaments, and inhibition of cytoplasmic streaming.
TL;DR: In this paper, the response of the capacitance dilatometer to superconducting order was studied using an ultrahigh-resolution capacitive dilatometers, and the onset of superconductivity is accompanied by highly anisotropic jumps of the expansivities in the a-b plane, which leads to a reduction of the orthorhombic splitting below the threshold.
Abstract: The response of the ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ lattice to superconducting order is studied using an ultrahigh-resolution capacitance dilatometer. The onset of superconductivity is accompanied by highly anisotropic jumps of the expansivities in the a-b plane. This leads to a reduction of the orthorhombic splitting below ${\mathit{T}}_{\mathit{c}}$, which suggests that superconductivity favors a symmetric (b=a) ${\mathrm{CuO}}_{2}$ plane. Little effect is seen along the c axis. Superconducting fluctuations are for the first time clearly observed in the lattice expansion.
01 Oct 1991
TL;DR: In this article, the authors present a scheme for absolute calibration of a polarimetric scattering range, based on network analysis, which requires the precise calculation of only one reference target.
Abstract: The authors present a scheme for absolute calibration of a polarimetric scattering range. All free-space polarimetric radar cross section (RCS) and antenna measurements are subject to errors like coupling and residual reflections. The modeling of these errors results in a 12-term error correction. The procedure for the error correction with three linear independent calibration targets and an isolation measurement is shown. Based on network analysis, a single reference calibration is introduced. This single reference calibration requires the precise calculation of only one reference target. As single references, spheres or flat plates are used. The references of the other targets are determined by the calibration procedure. The single reference calibration is suitable for all narrow and wideband, complex, polarimetric RCS, and antenna measurements. Measurements are shown for different targets which demonstrate the benefits of the single reference calibration. >
TL;DR: A tomographic image of the seismic structure beneath the Kenya rift shows its three-dimensional character, suggesting that the amount of crustal modification also varies along the length of the rift.
Abstract: A tomographic image of the seismic structure beneath the Kenya rift shows its three-dimensional character. In the lower crust, an axial zone of high seismic velocity varies in width and magnitude along the axis, suggesting that the amount of crustal modification also varies along the length of the rift. In the upper mantle, a steep-sided low-velocity body indicates the presence of partial melt, and its shape suggests that diapirs rise from a narrow wedge of asthenosphere beneath the rift axis in response to extension by pure shear.
TL;DR: In this article, the authors examined the properties of the quantum Lorentz group SOq(3, 1) using the matrix given in Ref. 14 and showed that this matrix together with the q-deformed metric C provide a representation of a BWM algebra.
Abstract: We examine the properties of the quantum Lorentz group SOq(3, 1) using the matrix given in Ref. 14. We show that this matrix together with the q-deformed metric C provide a representation of a BWM algebra. Using the projection operators which decompose the matrix into irreducible components, we give the general definition of the corresponding quantum space, i.e. the q-deformed Minkowski space and the q-deformed Clifford algebra. We also construct the q analog of Dirac matrices and show that they form a matrix representation of the q-deformed Clifford algebra.
TL;DR: It is shown that nitrous oxide reductase contains 2 distinct copper centres of which one is assigned to an electron‐transfer function, centre A, and the other to a catalytic site, centre Z, which may be a binuclear copper centre with at least 1 cysteine ligand.
TL;DR: In this article, a number of modifications are introduced to the linear elastic approach to establish a new parameter which is capable of correlating both long crack and short crack fatigue crack growth data.
TL;DR: The 1979 Fennoscandian Long-Range Project (FENNOLORA) was aimed at the determination of the detailed structure in the earth's mantle down to a depth of about 400 km as mentioned in this paper.
TL;DR: In this paper, a differential calculus for non-commutative Euclidean spaces is presented, which is required to be manifestly covariant under SO q (N) transformations.
Abstract: We construct a differential calculus on theN-dimensional non-commutative Euclidean space, i.e., the space on which the quantum groupSO q (N) is acting. The differential calculus is required to be manifestly covariant underSO q (N) transformations. Using this calculus, we consider the Schrodinger equation corresponding to the harmonic oscillator in the limit ofq→1. The solution of it is given byq-deformed functions.
TL;DR: This paper deals with the design of interpolating developable Bezier patches and deduces simple design criteria from necessary and sufficient conditions for these patches to be free of singular points.
TL;DR: An overview of research of high-speed transport components is given, and a parallel implementation of Open Systems Interconnection (OSI) protocols on transputer networks based on the parallel concepts discussed is described.
Abstract: An overview of research of high-speed transport components is given. High-speed protocols as well as high-speed implementations are considered. The use of parallelism to increase the performance of communication nodes is considered. A parallel implementation of Open Systems Interconnection (OSI) protocols on transputer networks based on the parallel concepts discussed is described. Selected performance values of the implementations are presented. The outlook on the design of high-speed transport components for future communication systems is examined. >
TL;DR: The model code for the design of concrete structures of the Comite Euro-International du Beton (CEB) includes extensive information on constitutive relations for concrete and reinforcing steel.
Abstract: The new model code for the design of concrete structures of the Comite Euro-International du Beton (CEB) includes extensive information on constitutive relations for concrete and reinforcing steel. In this model code relations are also proposed to predict fracture properties of concrete on the basis of fracture mechanics concepts. In particular fracture energy G F is given as a function of concrete grade, maximum aggregate size and temperature. In addition, bilinear stress-strain and crack opening relations are presented. In this paper these relations are verified on the basis of theoretical considerations and available experimental data.