publicationDate stringlengths 10 10 | abstract stringlengths 0 37.3k | title stringlengths 1 5.74k | doi stringlengths 11 47 ⌀ |
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1990-10-01 | Starting from prescriptions for the learning and retrieval of correlated time-independent patterns in spin glass models we present a class of learning rules for the implementation of temporal sequences of patterns into spin models with randomly delayed interactions. From biological motivation a learning process is devi... | On learning and recognition of temporal sequences of correlated patterns | null |
1990-10-01 | The variation of the convergence time τ , as a function of the storage capacity α is studied numerically for systems ranging in size from N =1000 to N =16,000 neurons. τ is found to increase like τ ∼exp[− A (α_c−α)] as one nears the critical storage capacity α _ c =0.142=0.002. | Slowing down of retrieval in the hopfield model | null |
1990-10-01 | A general description of the Electron Spin Polarization (ESP) dynamics is presented for photoinduced correlated radical ion spin pairs with particular significance to the respective primary processes in photosynthetic reaction centers. It applies to different coupling situations for the pair spins. The main emphasis is... | Time development of Electron Spin Polarization in magnetically coupled, spin correlated radical pairs | null |
1990-10-01 | The zitterbewegung is a local circulatory motion of the electron presumed to be the basis of the electron spin and magnetic moment. A reformulation of the Dirac theory shows that the zitterbewegung need not be attributed to interference between positive and negative energy states as originally proposed by Schroedinger.... | The zitterbewegung interpretation of quantum mechanics | null |
1990-10-01 | Physicochemical applications of the electron spin echo method | null | |
1990-10-01 | We reinvestigate the sign problem in the two-dimensional Hubbard model using the projector ground state Quantum Monte Carlo scheme with Langevin dynamics. Our interest is mainly motivated by the question: what is the parameter space in which simulations may be performed with reliable results and how does the average si... | Reinvestigation of the sign problem in the two-dimensional Hubbard model | null |
1990-10-01 | We rediscuss the Einstein-Podolsky-Rosen paradox in Bohm's spin version and oppose to it Bohr's controversial point of view. Then we explain Bell's theorem, Bell inequalities, and its consequences. We describe the experiment of Aspect, Dalibard, and Roger in detail. Finally we draw attention to the nonlocal structure o... | Bell's theorem and the nature of reality | null |
1990-09-01 | A nonlinear model of a warm-core ring is presented here. The model treats the warm core ring as a confined lens of fluid rotating on an f plane. A simple polynomial expansion of the hydrodynamic field variables about the center of mass of the lens provides the basis for an exact reduction of the hydrodynamic equations.... | Dynamics of warm-core mesoscale eddies | null |
1990-08-01 | The DPAC technique was applied to investigate the temperature dependence of the hyperfine interaction of^140Ce nuclei in yttrium metal. A weak damping of the anisotropy was observed, which is interpreted as a result of the short spin fluctuation time t _c for the Ce ions. | DPAC measurements on the Kondo system:^140Ce in yttrium | null |
1990-08-01 |
μ
^+ SR study of spin frustration in CsCoCl_3
| null | |
1990-07-01 | The temperature dependence of the local diffusion of fluorescent molecular probes of various polarities (alkane, long-chain fatty acid, short-chain alcohol and fatty acid), all labelled with 7-nitrobenz-2-oxa-1,3-diazol-4-yl in the cuticle of Clivia miniata Regel was studied by the technique of fluorescence recovery af... | Local motion and conformational changes in the cuticle of Clivia miniata Regel | null |
1990-07-01 | We have found a new long-lived mode that can be generated in the regime of pulsed NMR in^3He-B. The mode has a frequency different from both the Larmor one and that which was generated in the experiment of Corruccini and Osheroff by rf pulses longer than 104°. It does not correspond to stationary solutions of the Legge... | An attractor regime for pulsed NMR in^3He-B | null |
1990-07-01 | A Mössbauer time window has been positively used for studying the behavior of spins in Fe_ x Mn_1− x TiO_3 with x =0.50, 0.60 and 0.65 which are of typical Ising spin-glass systems. Spin dynamics above T _SG and T _N (RSG) (definition is given in the text) are discussed. In the RSG samples, the existence of contributio... | Studies on spin-glass freezing and antiferromagnetic long-range order in an Ising spin-glass system Fe_
x
Mn_1−x
TiO_3
| null |
1990-07-01 | We show how an inequality for the stiffness exponent for spin-glass models proposed by Fisher and Huse could be violated. We analyze their derivation and point out that their scaling arguments do not apply to investigations of the difference between systems with periodic and antiperiodic boundary conditions. As a conse... | Stiffness exponent, number of pure states, and Almeida-Thouless line in spin-glasses | null |
1990-07-01 | Determination of the composition and structure of paramagnetic coordination compounds in solutions from data on the spin relaxation of their nuclei | null | |
1990-06-01 | The “minimum linewidths” seen in the ESR linewidths against temperature plots, the dependence of line widths on the^63Cu nuclear magnetic quantum numbers and the Hubbard relation provide sufficient number of equations to determine the anisotropic ESR parameters in the case of axially symmetric Cu(II) complexes even whe... | Anisotropic ESR parameters of Cu(II) complexes in solutions and dynamics of solvent coordination: use of “minimum linewidths” | null |
1990-06-01 | Nuclear magnetic relaxation spectroscopy is used to study the molecular dynamics in a liquid crystal butoxy benzylidene pentylaniline (40.5) in the frequency range 4 to 30 MHz and the results are compared with two other members of the same homologous series (viz 40.8 and 40.6). Spin lattice relaxation time studies indi... | Proton magnetic relaxation studies of molecular diffusion in the liquid crystal 40.5 | null |
1990-06-01 | A theory is presented for nuclear spin conversion of methyl groups, where the total spin of the three protons changes from I =1/2 to I =3/2. The transition may be mediated by the magnetic dipolar interaction of the protons among themselves or with a nearby unpaired electron. In general the excess energy, i.e. the tunne... | Nuclear spin conversion of methyl groups | null |
1990-06-01 | Quantum Markov kinetic equation for a spin system with decay | null | |
1990-05-01 | Nonlinear dynamics and solitons in spin glasses | null | |
1990-05-01 | Based on the general solution given to a kind of linear tensor equations, the spin of a symmetric tensor is derived in an invariant form. The result is applied to find the spins of the left and the right stretch tensors and the relation among different rotation rate tensors has been discussed. According to work conjuga... | The invariant representation of spins with applications in the theory of finite deformations | null |
1990-05-01 | The hypothesis is advanced that nervous control of behavior is imprecise and that some behavioral evolution involves a selective pruning of variants similar to that which occurs in embryological canalization. Variations documented in many previous behavioral studies may have been selectively advantageous and therefore ... | Imprecision in the behavior ofLeptomorphus sp. (Diptera, Mycetophilidae) and the evolutionary origin of new behavior patterns | null |
1990-04-01 | Head trauma is often followed by epilepsy and may be related to the breakdown of red blood cells and hemoglobin within the CNS. Injection of hemoglobin or iron salts into the rat cortex is known to induce a chronic epileptic focus. We observed the formation of superoxide anion (O_2) and hydroxyl radical (·OH) after fer... | Biochemical pathogenesis of post-traumatic epilepsy | null |
1990-03-01 | The dynamics of glycan-protein interactions in immunoglobulins. Results of spin label studies | null | |
1990-03-01 | It is shown that the recently suggested energy-dependent torsion coupling constant can make the spin contributions of matter sources large enough to cancel the cosmological constant term at all stages in the early universe from the Planck epoch. | Torsion and the cosmological constant problem | null |
1990-03-01 | Cr(III) sorbed at the solid/water interface of latex and hectorite was studied by ESR spectroscopy in the presence of different inorganic ligands. The ESR spectra of the surface obtained in the presence of selenite, phosphate and fluoride can be explained in terms of ternary surface complex formation. This is contraste... | Study of inorganic ligand-chromium(III)-surface ternary complexes by ESR spectroscopy | null |
1990-03-01 | The various properties of quarkonium systems have been studies in the framework of a recently proposed potential model, which combines the asymptotic freedom at the large Q _2 and the multigluon effect at the lower Q _2 regions with the confinement at the large distance. Good agreements with experiments are found, incl... | A study of a possible unified potential model | null |
1990-02-01 | The residual motion of spin labels bound to cysteine β93 and to lysines of methemoglobin has been studied by electron paramagnetic resonance spectroscopy. To separate the influences of the solvent and the protein environment of the label fluctuations, the correlation times, τ, were analyzed as a function of temperature... | Residual motion of hemoglobin-bound spin labels and protein dynamics: viscosity dependence of the rotational correlation times | null |
1990-02-01 | The physical properties of lipid bilayers with a similar composition to the outer and inner leaflets of the human erythrocyte membrane have been examined in protein-free model systems. The outer leaflet (OL) was represented by a phospholipid mixture containing phosphatidylcholine and sphingomyelin extracted from human ... | Lateral diffusion of erythrocyte phospholipids in model membranes comparison between inner and outer leaflet components | null |
1990-02-01 | A study was made of the reproduction of Polydora variegata Imajima & Sato (Polychaeta:Spionidae) collected in Abashiri Bay on the Okhotsk Sea coast of Hokkaido, Japan, from May to December 1986. Large numbers of these bore into the shells of the cultured scallop Patinopecten yessoensis sown in Abashiri Bay. The spawnin... | Reproduction of the boring polychaetePolydora variegata inhabiting scallops in Abashiri Bay, North Japan | null |
1990-01-01 | A spin glass^l is a disordered and ‘frustrated’ magnetic system. Experimental results on some hundred spin glasses imply that these two general ingredients are the only requirements for the ‘universal’ behaviour of the dynamics. In this article I will exemplify some key observations of the zero-field spin glass dynamic... | Experiments on Spin Glass Dynamics | null |
1990-01-01 | Despite considerable experimental work^1, no general agreement could yet be reached in the analysis of the long time dynamical behavior of spin glass systems. The difficulty of such an analysis arises from the existence of a very broad non-stationary distribution of relaxation times. The large width of the distribution... | Attempt at a Comprehensive Description of the Slow Spin Glass Dynamics | null |
1990-01-01 | In the dynamics of random magnetic systems, the dimensionality of the magnetic lattice plays a crucial role. Two-dimensional (d= 2) Ising spin glasses do not order until T=0 K, and accordingly the dynamics at long length scales is anticipated to be dominated by thermal activation over energy barriers.^1–3 Upon approach... | Spin-Glass Dynamics in the Two-Dimensional Ising System Rb_2Cu_1-xCo_xF_4
| null |
1990-01-01 | High T_c granular superconductors are concrete examples of 3D disordered arrays of coupled junctions. While their static critical properties have been studied to some extent^1–2, the study of their critical dynamics properties is still an open subject and it is made difficult by the existence of both intergranular and ... | Quasi-Equilibrium Dynamics and Non-Debye Relaxation in High T_c Granular Superconductors | null |
1990-01-01 | We introduce a lattice gas for particles with discrete momenta (1, 0, −1) and local deterministic microdynamics, which exactly reproduces Creutz's microcanonical algorithm for the ferromagnetic Ising model. However, because of the manifest gauge invariance of our variables, both the Ising ferromagnetic and spin-glass s... | Gauge-invariant lattice gas for the microcanonical Ising model | null |
1990-01-01 | Vector electron paramagnetic resonance spectroscopy (V-EPR) was successfully applied to an oriented lipid multibilayer to explore the anisotropic dynamics of fluctuations in the multibilayer in the slow-motion domain. V-EPR analyzed accurately the slow anisotropic motions in the gel phase. Anisotropic structure in the ... | Anisotropic Dynamics in an Oriented Lipid Multibilayer Revealed by Vector EPR Spectroscopy | null |
1990-01-01 | The methods and theories of solid-state NMR spectroscopy make it possible to study larger and more complex biological systems than with conventional NMR methods. They are also capable of providing unique information about the structure and dynamics of proteins. There are now a number of books and reviews that describe ... | Solid-State NMR Spectroscopy of Proteins | null |
1990-01-01 | A major objective of scientists for years has been the determination of molecular structures in non-crystalline environments. In general, researchers were forced to accept limited structural information due to the techniques available; certainly high-resolution structures such as those derived from x-ray diffraction (X... | Determination of DNA and Protein Structures in Solution via Complete Relaxation Matrix Analysis of 2D NOE Spectra | null |
1990-01-01 | The concept of damage spreading in the context of Monte Carlo is introduced. Subtle differences between heat bath and Glauber dynamics give rise to totally different behavior in the damage spreading. In general, damage spreading defines new dynamical phase transitions which in some cases can be related exactly to usual... | Damage Spreading | null |
1990-01-01 | The dynamical behaviour of complex physical systems can often be described by (simple) hierarchical models with a direct interpretation as diffusion in an hierarchical, system-dependent space^1. Two examples of such systems are spin glasses^2 and fully developed turbulence^3. Since the introduction of ultrametric topol... | Complexity of Hierarchical Relaxation | null |
1990-01-01 | A Transient Non Equilibrium Molecular Dynamics (NEMD) experiment is performed on an isotropic diatomic fluid originally at equilibrium: at t=0, the molecular centre of mass velocities are given an additional systematic component corresponding to a purely rotational flow of vorticity γ. This velocity field is then kept ... | On the Coupling between the Intrinsic Angular Momentum of Molecules and the Fluid Vorticity | null |
1990-01-01 | Neural networks are a special class of distributed active systems that consist of discrete two-state elements linked by long-range activatory and inhibitory connections. The applicability of these formal models to description of the actual neural net of the brain remains doubtful. They give what is probably no more tha... | Neural Networks | null |
1990-01-01 | In Chapter 2 we were concerned only with free electrons, for which m v = ħ k , and we assumed that the effect of fields E and B on an electron moving with velocity v was given by the Lorentz force equation 2.16 $$ m\dot{v} = h\dot{k} = - e(E + v \times B) $$ | The dynamics of Bloch electrons | null |
1990-01-01 | These lectures review the basic aspects of learning in simple neural networks and outlines how one can study learning as a statistical dynamical process, stressing the role of phase transitions. | Statistical dynamics of learning | null |
1990-01-01 | In many disordered systems, such as glasses (mineral or polymeric) or spin glasses, slow relaxations are observed^1–3. The decay rate of fluctuations is not a constant, as it is for exponential relaxation, but it increases with time. The main question is: where do these slow relaxations come from? The various approache... | Dynamical Properties of Hierarchical Polymeric Cluster Solutions | null |
1990-01-01 | It is shown how correlations in spin systems can be described in terms of geometrical clusters. For the q-state Potts model exact relations are given between connectivity and thermal properties. A cluster dynamics developed by Swendsen and Wang is described. At criticality these clusters are shown to have a fractal str... | Correlations in Thermal & Geometrical Systems | null |
1990-01-01 | The nonexponential relaxation of spin glasses, and other complex physical system can be interpreted within two different paradigms. In the ‘parallel’ approach, one assumes the existence of ‘effectively’ independent entities, i.e. clusters or droplets as for instance in Refs. [1,2]. Each of these is characterized by a r... | Simple Models for Complex Relaxation | null |
1990-01-01 | Electron transfer reactions between porphyrins and chlorophylls in their photoexcited triplet state (electron donors) and duroquinone (electron acceptor) were studied by laser excitation-Fourier transform (FT)-EPR spectroscopy (∼10 ns time resolution). This highly time-resolved EPR spectroscopy enables to differentiate... | Photoelectron Transfer Reactions: Porphyrins-Quinone. FT- and CW- Time Resolved- EPR Spectroscoies | null |
1990-01-01 | An extension of the Hopfield model is studied, whereby a certain number of ‘privileged’ patterns are ‘marked’, during the learning process. The replica trick is used in studying the retrieval properties of such networks. The relevance of the extension to other biological processes is also discussed. | Learning and retrieving marked patterns | null |
1990-01-01 | The effect of the electron spin state on the differential Compton cross section in the field of a plane electromagnetic wave of different configurations is investigated in detail in relation to experiments on the observation of the electron self-polarization effect in collector rings. | Determination of the radiation polarization of charges | null |
1990-01-01 | We report in this paper our experiments about the magnetic excitations in the disordered system Mg_1-xCo_xCl_2. The compound CoCl_2 has the hexagonal CdC1_2 structure and is antiferromagnetic below 24.9K. The or- dered state spin structure is such that spins within a metal layer form a ferromagnetic sheet and the spins... | Magnetic Excitations in the Disordered System Mg_1-xCo_xCl_2
| null |
1990-01-01 | The reaction mechanism in ( γ,p ) and ( γ,n ) reactions at intermediate energies has been studied in the frame of the self-consistent RPA-SK3 continuum theory, fulfilling current conservation. Mean-field exchange currents, gauge-invariant with the RPA Hamiltonian, are expressed through an effective nucleon mass m ^SK (... | Photonuclear reactions at intermediate energies by self-consistent RPA-SK3 continuum theory: The mean-field quasideuteron effect | null |
1990-01-01 | Observations have been made on the effect of varying the concentration of a non-adsorbing polymer in sterically stabilised concentrated suspensions of organic crystals (a herbicide) using an ultrasound velocity scanning technique. The rate of sediment or floc consolidation is satisfactorily quantitatively interpreted u... | Consolidation of Depletion Flocculated Concentrated Suspensions Influence of Non-Adsorbing Polymer Concentration on Consolidation Rate Constants | null |
1990-01-01 | Properties of neural networks with multi-state neurons | null | |
1990-01-01 | The Kauffman model is used as an example of a cellular automaton with fractal and multifractal properties. A close connection between the Kauffman model and percolation is established and we are able to describe a general class of automata—the Ising cellular automata. The fractal properties of this family are numerical... | Damage Spreading: The Search for Multifractality & Multiscaling | null |
1990-01-01 | Organic free radicals and most transition metal ions are characterized by the presence in their structure of one or more unpaired electron(s), that is, they are paramagnetic, and may produce electron spin resonance (ESR) signals in both the free state and any organic and inorganic association in which they maintain unp... | Application of Electron Spin Resonance (ESR) Spectroscopy in Soil Chemistry | null |
1990-01-01 | The reason for studying the violent collisions of protons is to obtain information about the inner structure of the proton. To study the inner structure of the proton and to see what its constituents look like, one must observe large values of P _┴ which is the canonically conjugate variable to the impact parameter. No... |
$$\text{High-P}^2_\bot$$
spin dependent measurements | null |
1990-01-01 | Crystals of ^57Fe enriched reaction centers have been investigated by Mössbauer spectroscopy. The cytochrome irons are in the low spin ferric state. The non-heme iron of the electron accepting side is partly ferrous high spin and partly ferrous low spin (or ferric high spin). Under the conditions of the experiment sodi... | Mössbauer Spectroscopy on Photosynthetic Bacteria: Investigation of Reaction Centers of Rhodopseudomonas Viridis | null |
1990-01-01 | α-Lactalbumin (o-LA) plays a unique role in milk biochemistry. That is, its function appears to be only as a modifier protein in lactose biosynthesis by directing the specificity of galactosyl transferase from the acceptor substrate N-acetylglucosamine (GlcNAc) to glucose (Glc). Specifically, α-lactalbumin lowers the K... | NMR Studies of the Structure and Environment of the Milk Protein α-Lactalbumin | null |
1990-01-01 | Two-dimensional (2-d) magnetic systems show a variety of properties depending on the symmetry in the spin space, the interaction range, the quantum nature and also the symmetry of the lattice on which the spins are located. No real substance, however, is an ideal system for which the Hamiltonian can be written in terms... | Neutron Scattering Experiments on Two-Dimensional Heisenberg and Ising Magnets | null |
1990-01-01 | The changing macro-economic conditions accompanied by a changing international division of labour have led to reinforced entrepreneurial competition in industrialized countries since the early seventies and as a consequence speeded up industrial restructuring. In the course of this restructuring process many firms have... | Regional Differences and Determinants of Entrepreneurial Innovation — Empirical Results of an Austrian Case Study | null |
1990-01-01 | Portugal | null | |
1990-01-01 | Aging phenomena in spin glasses (SG) are very important and worth studying, but relaxation without aging may also be a good starting point. Recently, Granberg et al ^1 had experiments on such relaxation by observing the time decay of the saturated remanent magnetization. No aging was found because the initial state for... | Cluster Model for Non-Equilibrium Relaxation in Spin Glasses | null |
1990-01-01 | For many years it has been known that primary charge separation in photosynthetic reaction centers is associated with spin polarized EPR-signals. Such signals can be detected directly in preparations containing PS I whereas their observation in bacterial reaction centers or PS II requires removal or decoupling of the n... | The Transient Photosystem I EPR Spectra Correlated Spin Pair Concept and Structural Conclusions | null |
1990-01-01 | The Langmuir-Blodgett (LB) films are solid organized media, where the studies of the chemical reactivity lead to a better comprehension of molecular interactions in the solid state, and to a development of a true molecular engineering. The LB technique allows the building of different structures at the molecular level,... | Solid-State Molecular Engineering in Langmuir-Blodgett Films | null |
1990-01-01 | Starting with a brief historical sketch, the traditional observing techniques relevant to the extraction of data and knowledge about the nucleus are discussed. Next, in Sect. 2.3, the theories and models for the interpretation of the data prior to the spacecraft encounters are reviewed. The emphasis of the other sectio... | The Nucleus | null |
1990-01-01 | “Heavy fermion” systems belong to the class of “intermediate valent systems”, in which the occupancy of the interior f -shell (4 f - in rare earth, 5 f in actinide compounds) is close to an instability. For simplicity the discussion will be restricted to Ce compounds (e. g. CeAl_3), where the concept of “valence fluctu... | Heavy Fermions: Theoretical Aspects | null |
1990-01-01 | The requirement for high-power (dipolar) decoupling in order to obtain improved resolution for dilute spins in solids is discussed. Proton relaxation parameters T_1, T_1ρ and T_2 are briefly introduced. The concept of spin locking is mentioned and followed by a discussion of cross-polarization using a simple thermodyna... | Relaxation and Double-Resonance in Solid-State NMR | null |
1990-01-01 | The first carbon-13 NMR spectrum of a metal carbonyl was reported in 1958 for iron pentacarbonyl by Cotton and Waugh.[1] The result, a single resonance in the carbonyl region, has been shown to be correct by several subsequent investigations.[2] In fact the single resonance for Fe(CO)_5 persists to −160 °C.[3] The stru... | Solid State Carbon-13 NMR of Metal Carbonyls | null |
1990-01-01 | Muon Spin Relaxation (μSR) measurements on (BEDT - TTF)_2Cu(NCS)_2 show that the magnetic field penetration depth λ_bc within the conductive b-c plane is about 8000 Å at T → 0. This value corresponds to the superconducting carrier density n_s = 1.6 × 10^20/cm^3 for an in-plane effective mass m* = 3.5m_e. Comparisons wi... | Fundamental Similarities between Organic and Cuprate Superconductors Shown by Muon Spin Relaxation Studies | null |
1990-01-01 | In the past decade there has taken place a steadily increasing expansion of NMR spectroscopy resulting in new applications in chemistry, material sciences, biology, and medicine. The success of this spectroscopic technique to large extent is founded on the introduction of modem one- (1D) and two-dimensional (2D) pulse ... | Two Dimensional NMR Spectroscopy — Basic Principles | null |
1990-01-01 | We have measured the temperature dependence of the penetration depth λ and surface resistance R_s using a resonant microwave cavity technique for different orientations of the ac magnetic field with respect to the conducting layers. The behavior of λ(T) and R_s(T) strongly suggests singlet pairing, and the anisotropy o... | The Electrodynamics of the Superconducting State of κ-(BEDT-TTF)_2Cu(MCS)_2
| null |
1990-01-01 | Finite temperature behaviour of the exciton bound states in the compressible molecular chain | null | |
1990-01-01 | Correlation of protein activity with structure is essential to researchers seeking an understanding of life processes at the molecular level. It is becoming important as well to commercial enterprises, where protein production is geared toward medical, industrial, and agricultural applications. The number of identified... | Methods of Proton Resonance Assignment for Proteins | null |
1990-01-01 | The propagation of light in a random medium is considered. Coherent back scattering in the region of weak localization and near the mobility edge is discussed and a scaling theory is presented. Results on the fluctuations and correlations in the transmitted light are presented. The effects of inelastic scattering arisi... | Coherent Back Scattering and Other Optical Effects in Random Media | null |
1990-01-01 | This book thoroughly addresses problems confronting elderly individuals, particularly with respect to their health care problems. In this chapter we draw on such considerations but focus on the additional challenges created by acknowledging that elderly persons as a group are contenders for society’s inevitably limited... | Justice and the Allocation of Health Care Resources | null |
1990-01-01 | Some of the author’s views on the state of transition calculations in 1989, and on desirable future trends, are presented. Aeronautical applications are kept in mind, and the emphasis is on wall-bounded flows. It is argued that some of the effort now devoted to the late stages of transition in excessively confined peri... | Computation of Instability and Transition | null |
1990-01-01 | The major approaches to child clinical neuropsychology have used an adult model of neuropsychological functioning as an initial framework for analysis of cognitive dysfunction in childhood.^1-4 While this strategy seemed logical and initially proved useful as a model for the organization of ideas about brain-behavior r... | Neuropsychological Evaluation of Children | null |
1990-01-01 | The LEAR machine has been described on several occasions, in particular last year during the Second Course of this Erice School [3]. It will not be repeated here, but we will give some background information to show the time scale of the successive improvements in the machine. | Lear in the Nineties | null |
1990-01-01 | The transverse spin susceptibility for a Fermi liquid in a uniform magnetic field is calculated in the collisionless regime using the Landau theory of Fermi liquids. The singularities corresponding to the l=0 and l=1 spin waves are investigated in pure and dilute^3He as a function of the wave vector q up to the thresho... | Magnetic susceptibility and collisionless spin waves in liquid^3He and^3He-^4He mixtures | null |
1990-01-01 | The subtitle of my paper — The Lesson of Physics — is an overstatement in several ways: The lesson is, of course, no more than the lesson I have extracted from the history of physics for myself, and that I would like others to believe as well. Hence, it is only one lesson among several possible lessons, i.e. a view sug... | Method, Theory, and Statistics: The Lesson of Physics | null |
1990-01-01 | Statistical mechanics and error-correcting codes | null | |
1990-01-01 | Polycrystalline (CH_3)_4NOH·5 H_2O ( I ) and (CH_3)_4NOD·5D_2O ( II ) have been studied by^1H NMR lineshapes, second moments and spin-lattice relaxation times and by^2H NMR lineshapes as a function of temperature. From low temperatures the first motion to occur is reorientation of the internally rigid (CH_3)_4N^+ ion a... | NMR studies of molecular motion in tetramethylammonium hydroxide pentahydrate | null |
1990-01-01 | The aim of these notes is to provide a general view of the status of the violation of PC in the middle of 1988 from both the experimental and the theoretical sides. We concentrate our comparison between theory and experiment on the minimal standard model and we develop the necessary material for such a comparison empha... | Status of PC Violation | null |
1990-01-01 | We now turn to the second case of the general problem (Ĥ in the variables  _ i is not linearized) with examples of models of the Heisenberg chain with the Hamiltonian: 6.1 $$ \hat H = {\rm{ }} - \sum\limits_n {({I_x}\hat S_n^x\hat S_{n + 1}^x + {I_y}\hat S_n^y\hat S_{n + 1}^y + {I_z}\hat S_n^z\hat S_{n + 1}^z)} , $$ w... | Bose Gas, Integrable Nonlinear Schrödinger Equations and Landaulifshitz Models | null |
1990-01-01 | This paper is concerned with the analysis of historical records of abundance of coral and crown-of-thorns starfish Acanthaster planci) on the Great Barrier Reef. Analysis of the literature permitted the identification of 88 reefs for which coral and starfish abundances had been estimated on at least 3 occasions. Unfort... | Reef Syntax: An Exploratory Data Analysis of the Acanthaster Phenomenon Using Strings and Grammars | null |
1990-01-01 | Implementation of neural networks as a backbone of memory and user interface management systems allows greatly improve user-system interaction, as well as increased computer system performance. It does not violate the native structure of the system, but enables adaptive, situation-sensitive capability through presentat... | Neural Interactive Paradigm as a More Effective Computer System Environment | null |
1990-01-01 | Natural convection of a low Prandtl number fluid in a differentially heated shallow horizontal cavity has been studied numerically by means of a finite volume technique. The two dimensional flow undergoes a Hopf bifurcation as the Grashof number increases, and the oscillations are associated with growing and shrinking ... | Oscillatory Natural Convection in a Long Horizontal Cavity | null |
1990-01-01 | The Traveling Salesman Problem (TSP) is often cited as the prototypical “hard” combinatorial optimization problem. As such, it would seem to be an ideal candidate for nonstandard algorithmic approaches, such as simulated annealing, and, more recently, genetic algorithms. Both of these approaches can be viewed as varian... | Local optimization and the Traveling Salesman Problem | null |
1990-01-01 | In his book Mindstorms , Seymour Papert describes a vision of how computers can create “micro worlds” in which the innate beauty of mathematics, physics, and other sciences are revealed to children. Many of us who are interested in helping children develop their problem-solving skills share his vision. | Action Graphics | null |
1990-01-01 | The distributed termination problem : Formal solution and correctness based on petri nets | null | |
1990-01-01 | In this chapter we will discuss two systematic and structured methods of traversing the nodes and arcs of a graph. These traversal techniques can then be used as a powerful algorithm design tool on graph data types. These are indeed generalisations of the tree traversal methods which were used as a basis of efficient a... | Graph Traversals and Algorithms | null |
1989-12-01 | A review of temperature and salinity effects on rotifer population dynamics is presented together with original data of these effects for three clones of Brachionus plicatilis . There is a clear relationship between temperature and the intrinsic rate of increase, r : an increase of temperature — within the natural envi... | Salinity and temperature influence in rotifer life history characteristics | null |
1989-12-01 | We introduce a simple model describing the evolution of a population of information-carrying macromolecules. We discuss the asymptotic dependence of the variability of the population on different parameters, representing the severity or the fluctuations of the environment. We show the existence of a transition separati... | Population dynamics in a spin-glass model of chemical evolution | null |
1989-12-01 | We show that in 2-dimensional field theory, higher spin algebras are contained in the algebra of formal pseudodifferential operators introduced by Gelfand and Dickey to describe integrable nonlinear differential equations in Lax form. The spin 2 and 3 algebras are discussed in detail and the generalization to all highe... | Higher spin fields and the Gelfand-Dickey algebra | null |
1989-10-01 | We investigate the quantum dynamics of a periodically kicked nonlinear spin system which exhibits regular and chaotic dynamics in the classical regime. The quantum behaviour is characterised by the evolving eigenvalue distributions for the angular momentum components and the features, including recurrences in the quant... | The effect of measurement on the quantum features of a chaotic system | null |
1989-10-01 | We investigate the ratio of spin precession frequency to orbital frequency for a spinning charged particle confined to circular orbit in the equatorial plane of a compact object, with a uniform magnetic field, as described by the Wald and the Ernst potentials. In order to see the difference in behaviours for particles ... | Spin precession of a charged particle in a uniform magnetic field on a static space-time | null |
1989-08-01 | Growth of a floating-leaved plant, Hydrocharis dubia L., was examined under varying nutrient conditions between 0.3 and 30 mgN l^−1 total inorganic nitrogen. H. dubia plants cultured under the most nutrient-rich condition showed the highest maximum ramet density (736 m^−2), the highest maximum biomass (80.4 g dry weigh... | Growth and biomass turnover ofHydrocharis dubia L. cultured under different nutrient conditions | null |
1989-07-01 | The dynamics of a soft-spin version of the van Hemmen spin-glass model is considered in the thermodynamic limit. Phase and bifurcation diagrams for quenched distributions are given. Phase coexistence, metastability, and hysteretic phenomena are found. | Dynamics of a soft-spin van Hemmen model. I. Phase and bifurcation diagrams for stationary distributions | null |
1989-07-01 | Permeabilities for a homologous series of amine and carboxylate nitroxide spin probes were measured in human red blood cells by an electron paramagnetic resonance (EPR) method. Permeabilities determined in this study are much lower than would be predicted for a sheet of bulk hydrocarbon and the polarity of the rate-lim... | Amine and carboxylate spin probe permeability in red cells | null |
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