publicationDate stringlengths 10 10 | abstract stringlengths 0 37.3k | title stringlengths 1 5.74k | doi stringlengths 11 47 ⌀ |
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1991-05-01 | A simple model of a population of asexually reproducing individuals, evolving in a flat fitness landscape, is defined. It is shown that the model is equivalent to a dynamical system with stochastic dynamics, the Annealed Random Map Model. Thus, it is possible to solve exactly for the genealogy statistics and for the ge... | Evolution in a flat fitness landscape | null |
1991-05-01 | The motion of spin particles in the Schwarzschild field is examined in this paper. It is shown that Mathisson-Papapetrou equations under additional conditions $$\mathop L\limits_j {\text{ }}S^{\alpha \beta } {\text{ = }}0$$ , where $$\mathop L\limits_j$$ is the Lie derivative of the Killing vector ξ_ j , permit only ra... | The spherically-symmetrical trajectories of spin particles in the Schwarzschild field | null |
1991-05-01 | A method for quantitative determination of cross-relaxation rates of macromolecules in solution is developed. The method is based on the analysis of the intensities of cross peaks in 3D NOE-NOE spectra. The linear combination of the intensities of 3D peaks (spin-diffusion peaks, back-transfer peaks) results in an expre... | Determination of cross relaxation rates by 3D NOE-NOE spectroscopy | null |
1991-04-01 | A new cluster-effective-field theory of spin glasses is formulated. Basic formulas for the spin-glass transition point and the spin-glass susceptibility in the high-temperature phase are obtained. The present theory combined with the coherent-anomaly method is shown to be useful to estimate the true critical point and ... | Effective-field theory of spin glasses and the coherent-anomaly method. I | null |
1991-04-01 | Using real replicas to describe the many-state phase space of the Sherrington-Kirkpatrick model of a spin glass, we rederive the Sompolinsky free energy for the ground state. We propose an interpretation of the order parameter function q(x), x ε 〈0,1〉, from the Sompolinsky free energy directly within the real replica s... | New interpretation of Parisi-Sompolinsky mean-field solution for spin glasses | null |
1991-03-01 | Spin dynamics of^3He-^4He dilute solution have been studied in the collisionless regime by NMR methods. In cw NMR experiments, we observed spin waves in a magnetic field gradient. The frequency difference between the first mode and the others obeyed a two-thirds power law in the strength of the field gradient. By using... | Nonlinear effects on spin waves in^3He-^4He dilute solutions | null |
1991-02-01 | Muon spin rotation studies of the role of solvent in captodative interactions of cyclohexadienyl radicals | null | |
1991-02-01 | The relationship between life-history characteristics and population dynamics were investigated in the onuphid polychaete Kinbergonuphis simoni (Santos, Day and Rice) between 1982 and 1987. The studied population is located in Upper Tampa Bay, Florida, USA. This worm attains sexual maturity at 5 to 10 mo of age, depend... | Life history and population dynamics ofKinbergonuphis simoni (Polychaeta: Onuphidae) | null |
1991-02-01 | Transverse-field (TF) muon-spin-relaxation (μSR) and Mössbauer experiments on the uniaxial insulating spin glass Fe_2−xTi_1+xO_5 ( x =0.25) have been performed near and below the spin-glass temperature ( T _g). The effect of a transverse field on the spin-freezing process and spin-glass state has been investigated by m... | Spin-cluster effects and frustration in the uniaxial spin glass Fe_2−xTi_1+xO_5
| null |
1991-02-01 | Muonium in liquid SiCl has been observed for the first time at low temperature (−65°C) The observed polarization of muonium is as much as 25% of the total spin polarization and shows a fast relaxation rate. | Muonium in silicon tetrachloride | null |
1991-02-01 | We analyze the apparent increase in entropy in the course of the spin-echo effect using algorithmic information theory. We show that although the state of the spins quickly becomes algorithmically complex, then simple again during the echo, the overall complexity of spins together with the magnetic field grows slowly, ... | Algorithmic treatment of the spin-echo effect | null |
1991-02-01 | In this paper we review our recent experiments conducted at TRIUMF on muonium diffusion in alkali halides. First, the technique of longitudinal-field muonium spin relaxation ( T _1) due to nuclear hyperfine interaction, an indispensable tour de force for the present work. is described. It is demonstrated in KCl that th... | Quantum diffusion of muonium in insulators | null |
1991-02-01 | Neural networks composed of neurons with Q _ N states and synapses with Q _ ℐ states are studied analytically and numerically. Analytically it is shown that these finite-state networks are much more efficient at information storage than networks with continuous synapses. In order to take the utmost advantage of network... | Finite-state neural networks. A step toward the simulation of very large systems | null |
1991-01-01 | This lecture is concerned with the critical behaviour introduced into the dynamics of dilute systems by the divergence of the correlation length at the percolation threshold. In particular, dynamical properties of the geometrical structure will be discussed. | Dilution-Induced Critical Dynamics | null |
1991-01-01 | We report on the ^205T1 NMR (nuclear magnetic resonance) spectra of one-, two-, three-layer T1 containing compounds below and above the superconducting transition temperature T_c. Two different T1 nuclei were observed, namely those of the T10 layers (dominant line) and a T1 defect replacing Ca in the two- and three-lay... | Local Hyperfine Interactions of Delocalized Electron Spins: ^205TL Investigations in TL Containing High-T_c Superconductors | null |
1991-01-01 | Following the discovery of the new class of oxide superconductors in 1987^1 some workers rapidly suggested a possible link between the magnetic properties of the systems and their superconducting properties.^2 The cuprate systems are unique in that they exhibit a square planar lattice of copper spins, with spin 1/2, co... | Raman Scattering from Spin Fluctuations in the Cuprates | null |
1991-01-01 | In this chapter we give a condensed introduction to the basic features of computer simulation methods. We particularly review the Monte Carlo method of importance sampling and the principles of molecular dynamics simulations. Some of the systematic effects associated with computer simulations, such as finite-size effec... | Computer Simulation Methods | null |
1991-01-01 | Although the general form of the electronic structure of the CuO _ 2 -planes on the larger energy scale (∼1 eV ) is generally agreed upon, the reduced model on the relevant energy scale for superconductivity (∼10^-1 e V ) continues to be debated. The key issue is usually represented in terms of the adequacy of a one-ba... | Microscopic Models for Spin Dynamics in the CuO_2-planes with application to NMR | null |
1991-01-01 | Before discussing the “theories” it is necessary to define the subject more precisely. The best way to do so is to specify those high P _⊥ ^2 spin effects which must be described by the relevant theories. These effects provide “test facility” for “High P _⊥ ^2 Spin Theories”. They are listed below ^/1/: rapid increase ... | High P
_⊥
^2
Spin Theories | null |
1991-01-01 | Over the last 15 years there has been a profound crisis in many European “mature industries”: firms associated with success in the 1960s have been doing badly in the late 1970s and early 1980s. This has given rise to a number of searching questions, the most important being: Is strategy choice important? and Must strat... | Competition Dynamics Behind the Mask of Maturity | null |
1991-01-01 | The problem of collective spin fluctuations in disordered media is still one of the most interesting and intriguing questions in the physics of magnetic phenomena. Metals, alloys, and semiconductors are, of course, the most typical conducting systems with delocalized electron spins. In these cases electrons form a stro... | Collective Spin Waves in Maxwellian Electron Plasma | null |
1991-01-01 | A theory of spin glass relaxation based on some assumptions about the ground-state morphology and some scaling hypothesis is presented. It yields a closed formula for the AC and time-dependent susceptibilities in close agreement with the experimental results. | A Stochastic Model of Spin Glass Dynamics | null |
1991-01-01 | The superconductivity in the perovskite systems is one of the least well understood, but most important, aspects of the Cuprates. Antiferromagnetism is another important facet of these systems, but the magnetism is very well understood in comparison to the superconductivity. The ease with which the magnetic phenomena a... | Copper Spin Correlations Induced By Oxygen Hole Motion | null |
1991-01-01 | Soft binary processes (π^−p→π°n,p°n) in Regge phenomenology are described by secondary pole exchange (p;A_2,π). Secondary Regge poles ex. correspond mainly to planar processes with constituent quarks. These processes have space-time picture (Kaidalov — LUND — Artu ...). |
^3
P
_0 Model of Soft Binary Processes | null |
1991-01-01 | The recent results of extensive neutron scattering studies of the spin dynamics in YBa_2Cu_3O_6+x single crystals are reviewed. In the antiferromagnetic region (x=0.15) the spin waves spectrum shows that YBa_2Cu_3O_6+x is a quasi two-dimensional Heisenberg bilayer system with a weak XY anisotropy. Adding oxygen (x=0.37... | Inelastic Neutron Scattering Study of Spin Dynamics in YBa_2Cu_3O_6+x
| null |
1991-01-01 | A large variety of problems can be entered under the classification of random frustrated systems. The dynamical response of such systems appears to possess some universal characteristics, features common to systems very different in nature. Such features may be considered as being consequences of these two properties: ... | Relaxational Processes in Frustrated Random Systems: A Spherical-Spin Model | null |
1991-01-01 | Dilute magnets with short range interactions provide an interesting laboratory for theories of percolation.^1 Corresponding to the qualitative change of geometry of the percolating cluster as the concentration of magnetic ions decreases to the percolation threshold, the low frequency dynamics are different: coefficient... | Low Frequency Dynamics of Dilute Antiferromagnets at Percolation | null |
1991-01-01 | Protein folding is perhaps the most complex process that can be usefully described in purely atomistic terms.^1, 2 In order to function, a protein generally must take on a specific three-dimensional structure. It is, at present, unknown how this process occurs in the living cell. It is possible and, indeed, likely, tha... | Search and Recognition: Spin Glass Engineering as an Approach to Protein Structure Prediction | null |
1991-01-01 | It has long been established [1] that the ^13C chemical shifts of polymers observed in high-resolution ^13C NMR spectra of their solutions are sensitive to their microstructures, i.e., stereoregularity, comonomer sequence, and defect structures. More recently [2,3] it has been demonstrated that the microstructural sens... | Solid State ^13C NMR Studies of the Structures, Conformations, and Dynamics of Semi-Crystalline Polymers | null |
1991-01-01 | Experimental methods for studying the dynamics of liquid water and aqueous solutions are reviewed. The application of pressure permits water at liquid densities to be studied well into the supercritical temperature range and also permits an extension of the studies into the deeply supercooled range. | High Pressure NMR Studies on Water and Aqueous Solutions | null |
1991-01-01 | Long flexible polymers constitute physical systems with many internal degrees of freedom. At large enough scales, various molecular properties exhibit universal behavior such as the radius of gyration Rg which scales as M^ ν , where M is the molecular mass and ν is an universal exponent (see also lecture notes by R.C. ... | Dynamical Scaling in Polymer Solutions | null |
1991-01-01 | In comparison with other spectroscopic techniques used in biophysical research (such as absorption, circular dichroism, infrared, raman, fluorescence or EPR...), NMR investigation of biomolecules can be divided into two classes, one that could be called the conventional approach ; the second the structural approach . | Structural Studies of Biomolecules at High Field | null |
1991-01-01 | Rational mappings of ℂ P ^1 and dynamic properties of their iterations once again attract the attention of mathematicians. The dynamic theory of such mappings has been developed in the classical works of G. Julia and P. Fatou. The recent investigations of Sullivan, Thurston, Douady and Hubbard throw new light upon this... | What Is an Integrable Mapping? | null |
1991-01-01 | The discovery of the new high temperature superconductors has been at the origin of renewed interest in the physics of the 2-D quantum antife- rromagnet. At low temperatures La_2CuO_4and YBa_2Cu_3O_6 are anisotropic insulating antiferromagnets with Neel temperatures of 245 and 415 °K, respectively^1,2. The in-plane exc... | Magnetic Excitations in the Disordered Phase of the 2-D Heisenberg Antiferromagnet | null |
1991-01-01 | Since ESR spectroscopists started to use the halocarbon matrix isolation technique about a decade ago to study radical cations, many unstable intermediates have been characterised [ 1 ]. Most notable in this context are perhaps the radical cations of saturated organic compounds. The radical cations of alkanes have thei... | ESR Studies of Radical Cations of Cycloalkanes and Saturated Heterocycles | null |
1991-01-01 | When the Electron Spin Resonance (ESR) technique became available to chemists some thirty years ago it was soon noted, that many inorganic ionic solids with polyatomic ions yielded well-resolved ESR signals after exposure to ionizing radiation. The ESR signals were initially assigned to paramagnetic ‘centers’ in analog... | Anion Radicals in Inorganic Crystals | null |
1991-01-01 | Electron spin echo modulation (ESEM) and electron spin resonance (ESR) studies have been carried out for a series of x-doxylstearic acids (x-DSA, x=5, 7, 10, 12 and 16) and 4-octanoyl-2,2,6,6-tetramethylpiperidinyl-1-oxy (C8-TEMPO) spin probes in micellar solutions of sodium dodecylsulfate (SDS) and dodecyltrimethylamm... | Electron spin echo modulation and electron spin resonance studies of sodium dodecylsulfate and dodecyltrimethylammonium bromide micellar solutions: Effect of urea addition | null |
1991-01-01 | The progress in the understanding of the general features of static and dynamic critical phenomena, allowed by the use of renormalization group methods [1–2], raised in recent years the interest in experiments on the dynamics of spin fluctuations in simple paramagnets. The interpretation of the experimental data of mag... | Results of Mode Coupling Theory for the Paramagnetic and Critical Spin Fluctuations in Heisenberg Magnets | null |
1991-01-01 | There is a current active debate on the mechanisms of freezing in model glasses. Experimental freezing temperatures, derived from susceptibilities, are often found to vary approximately linearly with the logarithm of the measuring frequency. The theoretical problem being far from settled, experiments are much in need. ... | Dynamical Scaling in a Model Structural Glass | null |
1991-01-01 | The dynamics of individual and pairs of vortices in a classical easy-plane Heisenberg spin model is studied. There are two types of vortices possible: in-plane, with small out-of-plane spin components present only at nonzero velocity, and out-of-plane, with large out-of-plane spin components even when at rest. As a res... | Equations of motion for vortices in 2-D easy-plane magnets | null |
1991-01-01 | In what follows I would like to discuss the intrinsic oscillatory dynamics of a large network of neurone-like analog units. Using an appropriate entropie quantity called the ∈-entropy, the spontaneous activity of the net will be shown to be intermediate between low-dimensional chaos and random noise. This kind of netwo... | Spontaneous Activity in a Large Neural Net: Between Chaos and Noise | null |
1991-01-01 | Layered cuprates have unusual properties both in the normal and the superconducting states^1–15. It is believed that many of these have to do with the dynamics of low frequency spin fluctuations. For instance, in YBa_2Cu_3O_7, nuclear relaxation rate T _1 ^–1 for O(2,3) nuclei exhibits a linear (“Korringa-like”) temper... | Weak Coupling Analysis of Spin Fluctuations in Layered Cuprates | null |
1991-01-01 | The importance of idealized two-level (spin) systems in the study of critical phenomena has long been recognized. Several years ago at the Oulu Workshop^1 we introduced a new approach to the quantum optics of N two-level atoms interacting with a nearly resonant coherent electromagnetic field. This approach, which has n... | Quantum Statistical Microdynamics and Critical Phenomena | null |
1991-01-01 | Spin polarization in the dimers is proposed instead of charge and geometric asymmetry for the Si(100)-2×1 surface. Current symmetric and asymmetric dimer models are considered. Core level shift and total energy calculations support this proposal. An energy gain of about 0.5 eV per surface atom is obtained by including ... | Spin vs Charge Asymmetry in the Dimers of the Si(100)-2×1 Surface | null |
1991-01-01 | The properties of water confined in environments of low dimensionality were investigated by means of ^1H magnetic resonance relaxation (NMRR) analysis. As “water-container”, a water-in-oil microemulsion, (n-hexadecane (O), K-oletae (S), n-hexanol (CoS), water (W)), was chosen because, differential scanning calorimetry ... | W/O microemulsions as model systems for the study of water confined in microenvironments: Low resolution ^1H magnetic resonance relaxation analysis | null |
1991-01-01 | Selected results from recent experiments at the injector and ring cyclotrons are presented and briefly discussed. Experiments with polarized beams and targets have a long tradition at SIN/PSI. Rather than reviewing the history I shall concentrate on recent results which will serve to illustrate some of the physical iss... | Experiments with Spin at PSI | null |
1991-01-01 | Neutron scattering lends itself as a prominently powerful and direct tool to the investigation of magnetic phenomena, under the assumption that the magnetic scattering effects can be unambiguously identified and separated from an often stronger background of non-magnetic signal. This is the case in particular with rela... | Disordered, Low Energy Component of the Magnetic Response in Both Antiferromagnetic and Superconducting Y-Ba-Cu-O Samples | null |
1991-01-01 | In this paper we will discuss the results of some neutron scattering studies of antiferromagnetic spin fluctuations in the superconductors YBa_2Cu_3O_6+x and La_2-_x Sr _x CuO_4. We begin by discussing spin wave measurements in the antiferromagnetic phases of these compounds and comparisons between experimental and the... | Antiferromagnetic Spin Fluctuations in Cuprate Superconductors | null |
1991-01-01 | We explore the influence of the antiferromagnetic correlations on the NMR experiments in the YBa_2Cu_3O_7 and YBa_2Cu_3O_6.63. We discuss several ways of determining the Cu and O hyperfine couplings. It is demonstrated that with an antiferromagnetic correlation length ξ(T) which is growing with decreasing temperature i... | Influence of the Antiferromagnetic Fluctuations on the Nuclear Magnetic Resonance in the CU-O High Temperature Superconductors | null |
1991-01-01 | Synergetic computers are a new class of highly parallel computers which are constructed on the basic principles of synergetics and which use the analogy between pattern recognition and pattern formation. We show that the information flow in such computers can be determined explicitly. In this way the channel capacity, ... | Aspects of Information Processing: Information Flow in Synergetic Computers | null |
1991-01-01 | An electro-hydrodynamic model is presented for horizontal thunderclouds in the atmospheric boundary layer combining turbulent shear flow with space charge from fair- weather electricity. Horizontal electrification is obtained from circulation of charged eddies carrying a spin current through wind-sheared air layers. Up... | Boundary Layer Model and Calculation for Horizontal Thundercloud Electrification Preceding Natural and Rocket-Triggered Lightning | null |
1991-01-01 | In recent studies, we have explored various strategies for using isotope labeling in conjunction with 1D, 2D, and 3D NMR spectroscopy to obtain information about how proteins work. With larger proteins, a concerted approach to the assignment of protein spectra that makes use of all available information about through-b... | Computational Aspects of Multinuclear NMR Spectroscopy of Proteins at NMRFAM | null |
1991-01-01 | Electrons generated by ionizing radiation or photoionization can be trapped in a variety of solids. Extensive studies have been carried out on trapped electrons in alkali halide crystals in which the electron is trapped in an anion vacancy in the crystal lattice [ 1 ]. These trapped electrons have an intense optical ab... | Trapped Electrons in Disordered Matrices | null |
1991-01-01 | In this contribution we will discuss the analog of classical solitons in quantum spin chains. Strictly speaking, we will deal with the analog of solitary excitations, being interested in the manifestations of solitons in real physical systems more than in the properties of solitons in a rigorous mathematical sense. Fro... | Solitons in Quantum Spin Chains | null |
1991-01-01 | We show that the three band model for the copper-oxygen planes is not equivalent to the t-J model in its low energy physics by calculating the oxygen-oxygen spin correlation function exactly in a ferromagnetic background, and comparing it with the result given by the Zhang and Rice approximation, i.e. zero The effect o... | Is there Spin on the Quasi-Particles in the Copper Oxygen Planes of High Temperature Superconductors? | null |
1991-01-01 | Supersymmetry concepts originally introduced in the high-energy physics have recently penetrated in the nuclear physics, condensed matter and statistical mechanics [1], In the last cases anticommuting variables are first introduced for pure combinatorical reasons, to replace the N→0 replica trick. But recently there ha... | Integrable N ≤ O Component Nonlinear Schrödinger Model, Phase Transitions and Supersymmetry | null |
1991-01-01 | During the last few years the Potts glass model has attracted more and more attention. It is considered as a first step towards modelling the phase transition of structural and orientational glasses. A mean-field approach /1/ predicts a low temperature behavior completely different from what is known from Ising spin gl... | Finite-Size Scaling Study of the Simple Cubic Three-State Potts Glass | null |
1991-01-01 | It was predicted by Sokolov and Ternov [1] that when electron and positrons circulate in a high energy storage ring, the particle spins become polarized by the emission of synchrotron radiation. In practice, the equilibrium degree of polarization is strongly affected by so-called depolarizing spin resonances. A formula... | Higher Order Spin Resonances in High Energy Electron Storage Rings | null |
1991-01-01 | We consider the dibaryon resonance (DR) manifestation in the differential d(e,e’p)n cross section measured at Bonn[1].In the consideration we analyse the sensitivity of various contributions in the d(e, e’p)n cross section to the spin structure of the deuteron wave function (DWF) at short distances. The γ * +d→n+p ( γ ... | Dibaryon Resonances in e^− + d → e^− + n + p and the Deuteron Wave Function Structure at Short Distances | null |
1991-01-01 | Liquid-crystalline polyesters of the type: [-O-CO-(C_6H_4)_3-CO-O-(CH_3)_2-[O-Si(CH_3)_2]_y-(CH_2)_x-]_n were studied by means of high resolution ^13C solid state NMR spectroscopy. Experiments were performed at various temperatures in the solid and mesomorphic phase. The results of a spinning sideband analysis provide ... | On the Motion of the Mesogenic Unit in Liquid-Crystalline Polyesters | null |
1991-01-01 | As is well known, the unique structural feature connecting the various high T _ c materials is the presence of copper oxide planes^1. By varying the out-of-plane constituents these planes may be doped into the metallic and eventually superconducting state. In the insulating phase, the Cu 2+ sites have a spin of 1/2 and... | Light Scattering in Oxide Superconductors | null |
1991-01-01 | Many optimization problems in physics and biology lead to highly rugged cost functions. The most important examples come from the theory of spin glasses and from biological evolution. During the last decade new algorithms were developed in order to deal with such complex systems. Two techniques — known as simulated ann... | Optimization and complexity in molecular biology and physics | null |
1991-01-01 | The rotational mobility of paramagnetic solutes dispersed in partially hydrated macromolecules (proteins, polysaccharides, synthetic polymers) was measured using Electron Spin Resonance. A critical minimum amount of water was observed to be necessary for these molecules to reach a level of mobility of the same order as... | Influence of Water on the Mobility of Small Molecules Dispersed in a Polymeric System | null |
1991-01-01 | Experimental developments over the last two to three decades have made feasible detailed studies on the structure and spectroscopy of singly charged molecular ions, and a substantial body of information now exists on positively charged diatomic and polyatomic molecules covering the spectral region from the microwave to... | Studies of Multiply Charged Molecules by Ion Collision Techniques and Ab Initio Theoretical Methods | null |
1991-01-01 | We compare two optimization algorithms which glean their heuristic from nature: simulated annealing and evolution strategy. These algorithms are applied to difficult optimization problems: finding binary sequences with low autocorrelation, calculating ground states of certain spin glass Hamiltonians, and giving the opt... | Optimizing complex problems by nature's algorithms: Simulated annealing and evolution strategy—a comparative study | null |
1991-01-01 | We show that it is possible to give a causal, continuous and deterministic description of the motion of an individual system undergoing a transition between states using the de Broglie — Bohm interpretation of quantum mechanics. | What Happens during a Quantum Transition? | null |
1991-01-01 | I consider it a privilege to contribute the opening article to this Festschrift on the occasion of the 60-th birthday of Rudolf Kalman . | Dynamical Systems, Controllability, and Observability: A Post-Modern Point of View | null |
1991-01-01 | In this session delegates were asked to pose question and direct comments to problems that need to be tackled in the future. | Final Discussion Session | null |
1991-01-01 | In these recent years many progresses have been done in the study of the behavior of disordered systems, focusing on those features which are proper of disorder. The most interesting results have been obtained when the laws which control the evolution of the system are themselves disordered, i. e., chosen at random (se... | Random Heteropolymers Folding | null |
1991-01-01 | The status of dibaryon resonances in I = 0 and I = 1 states is discussed together with new data. | Structures in the Nucleon-Nucleon System | null |
1991-01-01 | Aminoazaheterocycles are a group of organic molecules having an amino group attached to a carbon adjacent to a ring nitrogen in an aromatic system. The nucleic acid bases adenine, guanine, cytosine and the vitamin thiamine are examples of ortho-aminoazaheterocycles which exist naturally as essential compounds required ... | The role of cytochrome P-450 in the biological nuclear N-oxidation of aminoaza-heterocyclic drugs and related compounds | null |
1991-01-01 | Measurements of observables in antihyperon—hyperon production following the antiproton—proton collision in the threshold region offer an excellent opportunity to examine the dynamics of strangeness creation. At LEAR/CERN the PS185 collaboration has initiated and performed a set of measurements of the process: $$ \overl... | Investigation of the Reaction
$$
\bar pp \to \bar \Lambda \Lambda
$$
Close to Threshold at LEAR | null |
1991-01-01 | Recently there has been much interest in the study of the thermodynamics of many-body quantum mechanical systems by means of Quantum Monte Carlo (QMC) computer simulation techniques^(1–4). Applications of QMC methods to the study of spin systems, the Hubbard model, and to systems of boson and fermion particles have sho... | Quantum Monte Carlo Computation of Static and Time-Dependent Thermodynamic Properties of Lennard-Jones Crystals | null |
1991-01-01 | Granular metals consist of nanometer size metal granules embedded in an immiscible medium. They display a rich variety of physical properties as a result of their unique nanostructure and extra degrees of freedom. They are also suitable for the exploration of finite-size effects, enhanced and tailored properties of fun... | Granular Solids | null |
1991-01-01 | The 3.5-GeV electron stretcher ring ELSA has come into operation at Bonn university [1]. It is one of the first high duty factor machines which enable a new generation of experiments in the intermediate energy regime. | Polarization Program at ELSA | null |
1991-01-01 | The side chain motion of copoly(γ-methyl L -glutamate- co -γ- n -alkyl L -glutamate) was studied by a spin-probe technique to examine its dependence on the copolymer composition and alkyl side chain length. In a copolymer series with alkyl side chain length n =12 and 15 (where n is number of alkyl carbon), there is a t... | Side Chain Motion of Poly(L-glutamate)s Having Long Alkyl Side Chains as Studied by Spin-Probe Technique | null |
1991-01-01 | After a brief introduction on the subject, we review recent development on the theoretical understanding on the collective transport (Fröhlich conduction) in charge and spin density waves in quasi-one dimensional conductions. Especially the theoretical prediction on the depinning electric field in spin density wave (SD... | Collective Transport in Charge and Spin Density Waves | null |
1991-01-01 | Polynucleotide folding provides an example of a physically simple but mathematically still complex phenotype-genotype relation. The notion of the phenotype is extended to molecules. It is straightforward to identify the spatial structure of a polynucleotide with the phenotype. Tertiary structures are hard to encode in ... | Molecular Evolution as a Complex Optimization Problem | null |
1991-01-01 | I will discuss some experiments which study spin forces in high-P _⊥ ^2 proton-proton elastic scattering by using a polarized proton target and sometimes a polarized proton beam. Recall that if both protons are unpolarized then one can only measure the differential elastic cross-section. If either the beam or the targe... | Precise New High-P
_⊥
^2
Spin Measurements | null |
1991-01-01 | Spin-isospin excitations are common to all nuclei. The charge exchange reactions, (n,p) or (p,n), have been dominant in isolating these excitations. The quenching of the strength may be attributed to the excitation of Δ-isobar particle states. This is established by using two-body Ward-Takahashi relations that are a co... | Spontaneous-Symmetry Breaking and Gamow-Teller States | null |
1991-01-01 | Since the translocation of solutes across cell membranes is influenced by the physical state of the lipid bilayer, it was reasonable to assume that multidrug-resistant (MDR) cells, which maintain reduced intracellular levels of drugs, may have alterations in membrane lipids. Furthermore, alterations in membrane structu... | Membrane Lipids of Multidrug-Resistant Cells: Chemical Composition and Physical State | null |
1991-01-01 | In the history of Elementary Particle Physics quite a few experimental results aroused the interest of a broader Physics community. This time experiments with polarized electron and muon beams on polarized proton targets gave rise to excitements leading to headlines like [1] “The Proton Spin Crisis — Where, oh where is... | Ideas and Models for the Proton Spin | null |
1991-01-01 | Controlled solidification is one of the major techniques to produce engineering components since a close control of the microstructure, and thus of the properties of the material, is possible. Therefore, it is important to establish the precise correlation between the microstructure and the processing conditions. On th... | Array Disorder, Pattern Selection and Local Dendritic Transition in Cellular Directional Solidification | null |
1991-01-01 | In the past decade, the mathematical concept of fractal has exerted a great influence in a large variety of scientific disciplines. It is very common to find recent papers on the application of fractals to different fields in Physics, Chemistry, Biology, etc. The success of the fractal geometry in the description of ma... | Fractal Aspects of Galaxy Clustering | null |
1991-01-01 | This new release of the package contains 27 FORTRAN and 4 BASIC programs written for IBM-PC and compatible machines and Apple Macintosh II, Plus and SE personal computers. Widely used standard multivariate methods and specific data analytical techniques, some of them suggested by the author, are represented in the pack... | SYN-TAX IV. Computer Programs for Data Analysis in Ecology and Systematics | null |
1991-01-01 | This talk summarizes results on spin observables in the $$\bar p$$ p elastic and charge exchange reactions as measured at the Low Energy Antiproton Ring (LEAR) at CERN. In particular I will concentrate on the charge-exchange reaction, where the analyzing power has been measured for the first time. This study is part of... | First Measurements of Spin Observables in N
$$\bar N$$
Scattering Experiments at LEAR | null |
1991-01-01 | A brief examination of the physics we hope to learn from flavor production processes at low energies is presented. Results from the PS185 hyperon (strangeness) production experiment [2] at LEAR are discussed in a framework suitable for reactions taking place near threshold. Possible directions for future work in this f... | Flavor Production at Low Energies | null |
1991-01-01 | Since the beginning of this Symposium series our field has collected an impressive amount of data on the polarization of hyperons produced by high energy protons./1/ Unpolarized protons interacting with any target produce polarized Λ, ∑^+, ∑^−, ∑^0, Ξ^0, and Ξ^−when the produced hyperon is in the fragmentation region o... | Hyperon Polarization at High Energy | null |
1991-01-01 | The standard thermodynamic description of enzyme catalysis in terms of a single free energy surface implies a conflict between specificity and speed. The conflict seems not to be a prominent feature of nature, however, in part due to the fact that conformational motions of the enzyme actively help the substrate dock in... | Electronic Instabilities in Biological Information Processing | null |
1991-01-01 | Darwinian evolution is the outcome of the interplay of reproduction, mutation, and natural selection. One of the most important and difficult problems in understanding the emergence of life is to pinpoint the necessary conditions for the onset od Darwinian evolution. The beautiful experiments of Biebricher and collabor... | Disordered Systems and Evolutionary Models | null |
1991-01-01 | For the last ten years there has been considerable work on relativistic descriptions of proton scattering. By now, many of the basic ideas have been elucidated with detailed calculations. Therefore it is a good time to review relativistic effects on proton nucleus spin observables. First, a brief introduction is presen... | Relativistic Effects on Spin Observables | null |
1991-01-01 | The diffusion of water within a given pore and through adjacent pores has been studied in the porous silica, Vycor, using small angle neutron scattering and small-angle quasi-elastic neutron scattering. The spatial range measured -between 10 and 1000 Å - is below that observed by light scattering or spin-echo NMR but c... | Sans and Qens Studies of Vycor Containing D_2O/H_2O Mixtures | null |
1991-01-01 | The study of the spin-isospin response of nuclei induced by medium energy nucleon-nucleus scattering is of great interest, both, in theory and experiment. Major issues are: (1) the existence of spin resonances excited at forward angles and small energy loss, (2) the relative enhancement of the spin response as one appr... | The Nuclear Spin Response in Extended RPA Theories | null |
1991-01-01 | Our present understanding of the internal spin structure of the nucleon is very incomplete. | Future Experiments to Study the Internal Spin Structure of Nucleons | null |
1991-01-01 | In any angiographic technique, the different interaction of the technique with blood flowing in the vessels and stationary tissue determines the contrast and ultimate image quality. In MR angiography, these interactions fall into two general categories: a) phase-related and b) time-of-flight. | Basics of MR Angiography | null |
1991-01-01 | This workshop was the 2^ nd one on this topic, the first being held in Minneapolis in 1988.^1 With about 20 participants there was lots of discussion between the presentations. The main topics discussed were “Siberian Snakes”, “Proton Facilities” and “Electron Facilities”. This summary report is organized accordingly. | Summary of the 2nd Workshop on Siberian Snakes and Polarization in Circular Machines | null |
1991-01-01 | The CP ^ N ^-1-model for N ≫ 1 is considered as a model describing a disordered spin liquid phase within a controlled approximation. We show that integration over configurations of fields with a nonvanishing topological charge give rise to the ChernSimons term in the effective action for the RVB-gauge field. This term ... | Topological Effects in Disordered Phase of Two-Dimensional Magnet | null |
1991-01-01 | We study the problem of global smooth stabilization of cascade compositions of nonlinear globally asymptotically stable systems. Our main result is that global stabilization can be achieved if we can render the first system strictly passive for an output which spans the “unstable part” of the vector field of the second... | On Global Stabilization of Cascaded Nonlinear Systems | null |
1990-12-01 | A population of the grey red-backed vole, Clethrionomys rufocanus bedfordiae , was investigated on a 1 ha control grid and a 1 ha grid on which the voles were fed within a 2.1 ha outdoor enclosure in Hokkaido, Japan by live trapping from 1984 to 1986, for testing the Reproductive Suppression Model of Wasser and Barash ... | Lifetime reproductive success in reproductively suppressed female voles | null |
1990-12-01 | If f : Σ_ A → Σ_ A is an endomorphism of an irreducible shift of finite type, and p is a rational prime which divides the degree of f , then p divides every non-leading coefficient of χ_A. We also give constraints on the possible degrees of finite-to-one factor maps between shifts of finite type. | Degrees of finite-to-one factor maps | null |
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