Showing papers by "University of Bonn published in 1986"
TL;DR: In this article, a learning theory is proposed which models the influence of experience on end behavior in finite Prisoner's Dilemma supergames, which explains shifts in the intended deviation period.
Abstract: A learning theory is proposed which models the influence of experience on end behavior in finite Prisoner's Dilemma supergames. The theory is compared with experimental results. In the experiment 35 subjects participated in 25 Prisoner's Dilemma supergames of ten periods each against anonymous opponents, changing from supergame to supergame. The typical behavior of experienced subjects involves cooperation until shortly before the end of the supergame. The theory explains shifts in the intended deviation period. On the basis of parameter estimates for each subject derived from the first 20 supergames, successful predictions could be obtained for the last five supergames.
584 citations
TL;DR: This work gives a polynomial algorithm for the minimum cost flow and multicommodity flow problems in which the number of arithmetic steps is independent of the size of the costs and capacities.
Abstract: Khachiyan, and recently Karmarkar, gave polynomial algorithms to solve the linear programming problem. These algorithms have a small theoretical drawback; namely, the number of arithmetic steps depends on the size of the input numbers. We present a polynomial linear programming algorithm whose number of arithmetic steps depends only on the size of the numbers in the constraint matrix, but is independent of the size of the numbers in the right-hand side and objective vectors. In particular, it gives a polynomial algorithm for the minimum cost flow and multicommodity flow problems in which the number of arithmetic steps is independent of the size of the costs and capacities. The algorithm makes use of an existing polynomial linear programming algorithm. The problem of whether any algorithm has a running time that is independent even of the size of the numbers in the constraint matrix remains open.
495 citations
TL;DR: In this article, the existence of radial solutions to the problem of changing sign is studied for an arbitrary domain Ω = BR(0) ⊂ R n, if λ ϵ ]0, λ 1[ and n ⩾ 6.
297 citations
TL;DR: In this paper, the scaling of the central density ρ(0) at energies up to 900 GeV has been studied and a new form of central region scaling involving the densityρn(0)/ρ(0), expressed as a function ofz=n/〈n〉 is found.
Abstract: New data are presented on charged particle pseudorapidity distributions for inelastic events produced at c.m. energies\(\sqrt s \)=200 and 900 GeV. The data were obtained at the CERN antiproton-proton Collider operated in a new pulsed mode. The rise of the central density ρ(0) at energies up to\(\sqrt s \)=900 GeV has been studied. A new form of central region scaling is found involving the densityρn(0) for charged multiplicityn, namely that the scaled central densityρn(0)/ρ(0) expressed as a function ofz=n/〈n〉 is independent ofs. Scaling in the fragmentation region holds to 10–20%, and the small amount of scalebreaking observed here could be accommodated within the framework suggested by Wdowcyk and Wolfendale to account for both accelerator and cosmic ray data.
249 citations
TL;DR: A theory for adiabatic electron transfer reactions at metal electrodes is presented in this paper, which is similar to that of the Levich and Dogonadze theory for nonadiabatic reactions, but the rate is not calculated from perturbation theory but by techniques familiar from the Anderson-Newns model for adsorption.
239 citations
TL;DR: A broad spectrum of redox catalysts currently in use includes, inter alia, metal salts in very low or high oxidation states, halogens in various oxidation states and a wide variety of transition-metal complexes.
Abstract: The electrochemical formation and regeneration of redox agents for organic syntheses (indirect electrolysis) widens the potential of electrochemistry, as higher or totally different selectivities can often be obtained while at the same time the energy input can be lowered significantly. Higher current densities can also be obtained by preventing otherwise often encountered electrode inhibition. New types of redox catalysts can be formed in-situ and can be regenerated after reaction with the substrates. This principle is of increasing importance also for the application of already known redox agents with regard to environmental protection, since large amounts of a product can be generated in a closed circuit using only relatively small amounts of the redox reagent. Consequently the operation of such a process can be greatly simplified, and the release of ecologically objectionable spent reagents into the environment can be prevented. The broad spectrum of redox catalysts currently in use includes, inter alia, metal salts in very low or high oxidation states, halogens in various oxidation states, and, in particular, a wide variety of transition-metal complexes. A great deal of progress has recently been made in the application of organic electron transfer agents, since compounds have been found that are sufficiently stable in both the reduced as well as the oxidized state.
211 citations
TL;DR: It is shown that the Chvátal rank of a polyhedron can be bounded above by a function of the matrixA, independent of the vectorb, a result which, as Blair observed, is equivalent to Blair and Jeroslow's theorem that ‘each integer programming value function is a Gomory function.’
Abstract: We consider integer linear programming problems with a fixed coefficient matrix and varying objective function and right-hand-side vector. Among our results, we show that, for any optimal solution to a linear program max{wx: Ax≤b}, the distance to the nearest optimal solution to the corresponding integer program is at most the dimension of the problem multiplied by the largest subdeterminant of the integral matrixA. Using this, we strengthen several integer programming ‘proximity’ results of Blair and Jeroslow; Graver; and Wolsey. We also show that the Chvatal rank of a polyhedron {x: Ax≤b} can be bounded above by a function of the matrixA, independent of the vectorb, a result which, as Blair observed, is equivalent to Blair and Jeroslow's theorem that ‘each integer programming value function is a Gomory function.’
197 citations
TL;DR: It is suggested that low-dose sitostanol might be a useful hypolipidemic agent for the treatment of mild hypercholesterolemia.
180 citations
TL;DR: In this article, the authors present a model of the double layer of a semiconductor/molten salt interface with the first explicit contributions from the solvent and electronic structure and give an excellent description of the interfacial capacitance with at most one parameter.
169 citations
TL;DR: In this paper, the relation between perfectly competitive and monopolistically competitive equilibria is analyzed for a single market in which capacity constrained firms choose prices as strategies. And the authors provide a justification for perfect competition that is based on an explicit account of price formation.
Abstract: The relation between perfectly competitive and monopolistically competitive equilibria is analysed for a Bertrand-Edgeworth model of a single market in which capacity constrained firms choose prices as strategies. The market always has a Nash equilibrium in pure or mixed strategies. As the number of firms increases, the corresponding equilibria converge in distribution to a perfectly competitive price. This result provides a justification for perfect competition that is based on an explicit account of price formation. However, monopoly prices persist with a positive but vanishing probability. Regularity or well defined inverse demand functions are not required.
168 citations
TL;DR: Using a Y-organ in vitro assay to measure repression of ecdysteroid synthesis in the presence of putative moult-inhibiting hormone (MIH), it was found that both the hyperglycemic hormone (CHH) and a novel peptide (argued to represent the MIH) inhibited ecdystersoid synthesis.
Abstract: Using a Y-organ in vitro assay to measure repression of ecdysteroid synthesis in the presence of putative moult-inhibiting hormone (MIH), in conjunction with HPLC separation of sinus gland neuropeptides ofCarcinus maenas, it was found that both the hyperglycemic hormone (CHH) and a novel peptide (argued to represent the MIH) inhibited ecdysteroid synthesis. The latter was purified to homogeneity, and amino acid analysis showed that it is a 61 residue peptide (minimum molecular mass 7,200 Da) with the following amino acid composition: Asx9; Thr2; Ser2; Glx7; Pro1; Gly4; Ala2; 1/2 Cys4; Val4; Met1; Ile3; Leu5; Tyr1; Phe3; His3; Trp2; Lys2; Arg6. The N-terminus appears to be blocked. MIH is at least 20 times more potent than CHH in repressing ecdysteroid synthesis and is active at concentrations of less than 250 pmol/l. There may be structural similarities between CHH and MIH, howeve, MIH displays no CHH radioimmunoreactivity or hyperglycemic activity. The physiological significance of CHH in controlling ecdysteroid titres is not known.
TL;DR: In this paper, a negative binomial distribution is used to describe the energy variation of the average charged multiplicity at the CERN antiproton-proton collider operated in a new pulsed mode.
TL;DR: The uptake of α-[ 14 C] methylglucoside by the phosphoenolpyruvate-dependent phosphotransferase system was stimulated by Pep 5, supporting previous results that pep 5 abolishes the membrane potential.
Abstract: The cationic bactericidal peptides Pep 5 and nisin render membranes permeable to low-M r compounds. All Gram-positive bacteria treated with these peptides showed an immediate efflux of entrapped radioactive markers. The uptake of α-[ 14 C] methylglucoside by the phosphoenolpyruvate-dependent phosphotransferase system was stimulated by Pep 5, supporting previous results that pep 5 abolishes the membrane potential. Oxygen consumption was inhibited, presumably due to lack of ADP. Escherichia coli became sensitive to Pep 5 and nisin when the outer membrane was bypassed by osmotic shock or by formation of cytoplasmic membrane vesicles. In contrast, Mycoplasma cells and erythrocytes were unaffected by Pep 5 and nisin in concentrations up to 1 mM. Human lung fibroblasts released only small amounts of ATP when treated with Pep 5 and nisin in μM concentrations. Eukaryotic and Mycoplasma cells were disrupted more effectively by the bee venom peptide melittin, which displays overall structural similarities to Pep 5 and nisin. Various artificial membranes were not affected by Pep 5, nisin, or melittin.
TL;DR: A highly polymorphic DNA probe genetically linked to the locus of autosomal dominant polycystic kidney disease was used in linkage studies for prenatal diagnosis in a nine-week fetus at risk for the disease.
TL;DR: Using the orthogonal complement likehood function, an iterative procedure for the maximum likelihood estimates of the variance and covariance components is derived in this article, and it is shown that these estimates are identical with the reproducing estimates of a locally best invariant quadratic unbiased estimation of variance.
Abstract: Using the orthogonal complement likehood function, an iterative procedure for the maximum likelihood estimates of the variance and covariance components is derived. It is shown that these estimates are identical with the reproducing estimates of the locally best invariant quadratic unbiased estimation of variance and covariance components. Successive approximations of the maximum likelihood estimates are given in addition.
TL;DR: A vertex operator construction for affine Kac-Moody algebras associated with non-simply-laced finite-dimensional Lie algesbras, using free boson and interacting fermion fields, is given in this paper.
Abstract: A vertex operator construction is given for the level one representations of the affine Kac-Moody algebras associated with non-simply-laced finite-dimensional Lie algebras, using free boson and interacting fermion fields. The fermion fields are constructed explicitly and a detailed discussion is given of the theory of the cocycles necessary for this and other vertex operator constructions. The construction is related in detail to the folding of Dynkin diagrams and a generalisation of it yields Freudenthal's magic square.
TL;DR: In this paper, a study of centrally produced mesons in 3 × 106 events with two small-angle protons at the CERN Intersecting Storage Rings is presented, where the reaction mechanism is dominated by double pomeron exchange.
TL;DR: In this article, an approach to the problem for the case of tangential magnetic fields at the heliopause was described by a complete set of two-fluid plasma equations including a hybrid MHD-formulation of wave-particle interaction effects.
Abstract: Existing heliopause models are critically rediscussed under the new aspect of possible plasma mixing between the solar wind and the ambient ionized component of the local interstellar medium (LISM). Based on current kinetic plasma theories, effective diffusion rates across the heliopause are evaluated for several models with turbulence caused by electrostatic or electromagnetic interactions that could be envisaged in this context. Some specific cases that may lead to high diffusion rates are investigated, especially in regard to their LISM magnetic field dependence. For weak fields (less than 10−7 G), macroscopic hydrodynamic instabilities, such as of Rayleigh-Taylor or Kelvin-Helmholtz-types, can be excited. The resulting plasma mixing rates at the heliopause may amount to 20–30% of the impinging mass flow. Recently, an unconventional new approach to the problem for the case of tangential magnetic fields at the heliopause was published in which a continuous change of the plasma properties within an extended boundary layer is described by a complete set of two-fluid plasma equations including a hybrid MHD-formulation of wave-particle interaction effects. If a neutral sheet is assumed to exist within the boundary layer, the magnetic field direction is proven to be constant for a plane-parallel geometry. Considering the electric fields and currents in the layer, an interesting relationship between the field-reconnection probability and the electric conductivity can be derived, permitting a quantitative determination of either of these quantities. An actual value for the electrical conductivity is derived here on the basis of electron distribution functions given by a superposition of Maxwellians with different temperatures. Using two-stream instability theory and retaining only the most unstable modes, an exact solution for the density, velocity, and magnetic and electric fields can be obtained. The electrical conductivity is then shown to be six orders of magnitude lower than calculated by conventional formulas. Interestingly, this leads to an acceptable value of 0.1 for the reconnection coefficient. By analogy with the case of planetary magnetopauses, it is shown here for LISM magnetic fields of the order of 10−6 G or larger that field reconnection processes may also play an important role for the plasma mixing at the heliopause. The resulting plasma mixing rate is estimated to amount to an average value of 10% of the incident mass flow. It is suggested here that the dependence of the cosmic-ray penetration into the heliosphere on the distribution of reconnecting areas at the heliopause may provide a means of deriving the strength and orientation of the LISM field. A series of observational implications for the expected plasma mixing at the heliopause is discussed in the last part of the paper. In particular, consequences are discussed for the generation of radio noise at the heliopause, for the penetration of LISM neutrals into the heliosphere, for the propagation of cosmic rays towards the inner part of the solar system and for convective electric field mergings into the heliosphere during the course of the solar cycle, depending on the solar cycle variations. With concern to a recent detection of electrostatic plasma waves by plasma receivers on Voyagers 1 and 2, we come to an interesting alternate explanation: the heliopause, rather than the heliospheric shock front, could be responsible for the generation of these waves.
TL;DR: In this article, the transition moments between the three lowest gerade X 3∑-g, a 1Δ g and b 1∑+ g and ungerade states c 1 ∑- u, A′ 3Δ u and A 3 ∑+ u of the oxygen molecule have been calculated as a function of internuclear separation from 2·1 a.u. to 3·5 au.u, where the wavefunctions have thereby been expanded in a perturbation sum whereby the individual terms are large-scale MRD-CI
Abstract: The transition moments between the three lowest gerade X 3∑- g , a 1Δ g and b 1∑+ g and ungerade states c 1∑- u , A′ 3Δ u and A 3∑+ u of the oxygen molecule have been calculated as a function of internuclear separation from 2·1 a.u. to 3·5 a.u. The wavefunctions have thereby been expanded in a perturbation sum whereby the individual terms are large-scale MRD-CI wavefunctions and the expansion coefficients are the spin-orbit coupling coefficients obtained by using the Breit-Pauli one- and two-particle operator. A total of 18 states has been considered in the perturbation expansions; the corresponding potential energy curves are also given for all states. The AO basis set was of double-zeta plus polarization and Rydberg quality and involves a total of 56 contracted gaussians. The absorption oscillator strengths are also determined; the predicted values are 0·06 × 10-7 for c 1∑- u — X 3∑- g , 0·32 × 10-7 for A′ 3Δ u (Ω = ± 1) — X 3∑- g and 1·6 × 10-7 calculated for the strongest A 3∑+ u — X 3∑- g transition,...
TL;DR: The general bounds are improved to show that if G is a perfect graph with n nodes and w is a vector of integral node weights, then there exists a minimum w -covering of the nodes that uses at most n distinct cliques.
TL;DR: The electrogenerated products of propylenecarbonate and of its usual conducting electrolytes have been identified by on line mass spectrometry and their rate of formations have been measured as a function of the electrode potential.
TL;DR: In this article, an intertemporal model of consumption and bequest behavior is specified and analyzed as a game between generations and the main feature of this game is that no a priori restrictions (like linearity) are placed on the strategy choice of generations.
Abstract: An intertemporal model of consumption and bequest behaviour is specified and analysed as a game between generations The main feature of this game is that no a priori restrictions (like linearity) are placed on the strategy choice of generations The paper gives an existence proof for perfect (Nash) equilibria in finite and infinite horizon versions of the model and determines characteristic properties of equilibrium strategies The main result is to demonstrate existence of stationary perfect equilibrium if the time horizon is infinite
TL;DR: The data indicate that the basis of the differences in oxidative capacity between EM and PM subjects is more likely to be due to a variant isozyme with defective catalytic properties than to a decreased amount of the isozyme.
Abstract: 1. The formation of the two major metabolites of the antiarrhythmic and oxytocic drug sparteine (2- and 5-dehydrosparteine) exhibits a genetic polymorphism. Two phenotypes, extensive (EM) and poor metabolizers (PM) are observed in the population. The frequency of the PM phenotype in various populations (Caucasian and Japanese) ranges from 2·3 to 9%2. The metabolism of sparteine is determined by two allelic genes at a single gene locus. PM subjects are homozygous for an autosomal recessive gene.3. The metabolism of sparteine is predominantly under genetic control as treatment with drugs such as antipyrine and rifampicin known to induce oxidative drug metabolism elicited only marginal changes in sparteine metabolism.4. The formation of 2-dehydrosparteine in human liver microsomes from EM and PM subjects showed a more than 40-fold difference in Km between EM and PM subjects. However, Vmax-values were almost identical in both groups. These data indicate that the basis of the differences in oxidative capacity ...
TL;DR: Concentrated salt solutions (brines) occur widely in the natural form of coastal lagoons, salt or soda lakes as well as in the man-made form of salterns or saltworks, inhabited by a limited number of specialized microorganisms, which use different strategies of haloadaptation.
Abstract: Concentrated salt solutions (brines) occur widely in the natural form of coastal lagoons, salt or soda lakes as well as in the man-made form of salterns or saltworks. They are inhabited by a limited number of specialized microorganisms, which use different strategies of haloadaptation. Extremely halophilic archaebacteria (Halobacteriaceae) compensate the high osmotic pressure of brines by high cytoplasmic K+ion concentrations. This requires appropriate adaptations of both the intracellular and extracellular functional macromolecules. Only some of the halophilic, halotolerant and extremely halophilic eubacteria follow this strategy; while the majority of them, and the halophilic algae, synthesize and accumulate in their cells organic compatible solutes (mono-, disaccharides, glycosylglycerols, sugar alcohols, amino acids, betaines). These compounds have besides their water-binding activity, protective functions for enzymes. In eubacteria the most important compatible solute is glycine betaine. Besides this substance, further new substances have been found, such as ectoine, for which functions as well as biosynthetic pathways have yet to be elucidated.