bluuebunny/crossref_metadata_2025 huggingface dataset:
Exact interior solutions in Einstein–Cartan–Yukawa theory
Authors: Krori K. D. , Borgohain P. , Das Kanika , Sarma Arunima
Published: October 2017

A simple method of obtaining singularity-free interior solutions in Einstein–Cartan–Yukawa theory is presented here. The validity of the solution is shown by considering two types of configurations, one Schwarzschild-like and the other Tolman-IV-like. We recover the Schwarzschild and Tolman-IV solutions as soon as the Cartan and Yukawa effects are switched off. In both cases the necessary physical conditions are satisfied. The possible role of torsion in halting the collapse of a massive star is also studied.
Is the anapole moment a physical observable?
Authors: Czyz H. , Kołodziej K. , Zrałek M. , Christova P.
Published: October 2017

The gauge dependence of the static (q2 = 0) characteristics of charged leptons in the framework of the GSW (Glashow–Salam–Weinberg) model was studied. It was found that the anapole moments of leptons are gauge dependent and hence cannot be considered as observables.
Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid
Authors: Merkulov I. A. , Papava Yu. I. , Ponomarenko V. V. , Vasiliev S. I.
Published: October 2017

A phase transition of the nuclear spin system of a solid with dipolar and indirect scalar interactions is considered. Monte Carlo simulations of the spin-system isothermic states and of the adiabatic demagnetization process have been made. The structures and energies of the ground states and the values of the critical temperatures, Tc, and minimal polarizations, ρc, at which adiabatic demagnetization leads to spontaneous spin ordering, calculated for the GaAs and CaF2 nuclear spin systems, are presented. The results of numerical simulations are compared with the experimental data for CaF2. The Weiss-field model is extended to the case of adiabatic demagnetization. The fluctuations of the local field are taken into account in the Gaussian approximation. It is shown that the proposed approach allows one to obtain asymptotically correct results both for [Formula: see text] and [Formula: see text]. The results of the calculations in the Gaussian approximation are compared with the numerical simulations.
Computer simulation of hopping conductivity in lightly doped two-dimensional semiconductors
Authors: Shegelski Mark R. A. , Barrie Robert
Published: October 2017

We present the results of a numerical simulation of a two-dimensional lightly doped compensated semiconductor. We choose a flat density of states with width Δε. We model the semiconductor as a Miller and Abrahams type resistor network; we use the full form of the resistance and do not take the low-temperature asymptotic form because we carry out the simulation at temperatures for which kT is of order Δε. We find that there is a wide temperature range for which [Formula: see text] with ε3 = 0.28Δε. This value of ε3 is considerably smaller than values found by others. We believe that the difference between our result and those of other workers may be attributed to their use of the low-temperature form of the resistance [Formula: see text] in a temperature range in which kT is of order Δε.
Sensitivity of experimental measurements in fitting interatomic potential energy curves
Authors: Keil Mark , Danielson Laurie J.
Published: October 2017

The sensitivity of scattering cross sections and dilute gas properties to the interatomic potential energy is determined directly for low reduced mass van der Waals interactions. The results are used to develop the most fruitful multiproperty fitting procedure for extracting reliable pair potentials. Error bounds can be estimated for the potentials thus obtained.
Calculation of the squeezing spectrum using a Feynman-diagram technique
Authors: Zaidi H.R.
Published: October 2017

The squeezing spectrum of a parametric amplifier, with a quantized pump field, is calculated using the Feynman-diagram technique. The results of the existing theories are recovered. The connection with the theory of superconductivity becomes transparent in this approach.
Anomalous behaviour in the capacitance of selenium Schottky diodes
Authors: Champness C. H. , Pan J.
Published: October 2017

Measurements on Se–Tl, Se–Bi, and Se–Au Schottky diodes, fabricated by evaporation of thallium, bismuth, or gold respectively, on a layer of crystallized selenium have shown an anomalous minimum of incremental capacitance with variation of applied voltage at a frequency below about 1 kHz. The voltage of the minimum varies consistently with the estimated barrier height of the junctions and suggests that it arises from a deep level located some 0.4 eV above the valence band of trigonal selenium. The disappearance of the effect with increasing frequency, while qualitatively consistent with this interpretation, indicates the level to be at 0.6 eV.
Auroral influence on ionospheric electron content
Authors: Niciejewski R. J. , Forsyth P. A.
Published: October 2017

A number of earlier investigations have established that regions of enhanced electron concentration in the ionosphere are often associated, both temporally and spatially, with optical auroral features. Attempts to determine whether these enhancements are completely accounted for by the same particle precipitation that causes the aurora have been only partially successful, largely because it is difficult to collect data over a sufficient time with sufficient spatial resolution to permit accurate modelling. This paper attempts to take one more step along this road by using photometer records, taken over a period of three quarters of an hour before a satellite pass, in a model computation to predict the total electron content of the ionosphere as observed during the satellite pass. The procedure is successful when the auroral activity is strong enough to dominate, but is unsuccessful when the aurora is weak and other ionospheric processes dominate.
Dynamics of roughening and growth of two-dimensional self-avoiding walks
Authors: Stauffer Dietrich , Jan Naeem
Published: October 2017

The one-dimensional surface of a two-dimensional lattice fluid is simulated by a method producing self-avoiding walks of varying lengths. Below the critical temperature, the surface width varies as the square root of the surface length in equilibrium, and at the critical point it varies as (time)1/3. Above the critical temperature, the width and the length of the surface increases initially as (time)1/2, whereas finally the "surface" fills the whole lattice. If, instead, we start above the critical point from a small ring, its squared radius of gyration and its length increase initially as (time)2/3. At the critical point, this growth from a small ring gives an average radius proportional to (length)0.75, as for self-avoiding walks.
Modèles pour l'interaction hadronique à haute énergie
Authors: Margolis B. , Valin P.
Published: October 2017

We report on a comprehensive analysis of inclusive as well as exclusive high-energy data on hadron–proton scattering. We are led to conclude that the parton model correctly describes inelastic phenomena and its shadow, the elastic channel, when additional geometric information in impact parameter space is added. The following scenario emerges: at low energies, collisions between quarks dominate, whereas at higher energies, gluon-initiated reactions are responsible for the total cross-section rise, which is due to the gluon's singular behaviour at small fractional longitudinal momentum. We obtain excellent agreement with all experimental high-energy data considered.
Constituent approach to total hadronic cross sections and high-energy elastic scattering
Authors: Buenerd M.
Published: October 2017

Total hadronic cross sections are analyzed in terms of the relative influence of the hadron geometry and of the interaction dynamics between the constituents, by means of a simple analytic model. It is shown that the interaction dynamics plays a dominant role. A numerical approach to the problem confirms this conclusion. It also allows us to perform a phenomenological analysis of existing data and to predict hyperon–nucleon differential cross sections on the basis of this analysis.
Experimental searches for exotic multiquark particles
Authors: Siebert H. -W.
Published: October 2017

Experimental searches for "exotic" multiquark hadrons are reported. In a hyperon beam experiment at the Organisation Européenne pour la Recherche Nucléaire-superproton synchrotron (CERN-SPS), evidence was found for narrow states at 3.1 GeV/c2, with charges + 1,0, and −1, decaying into Λ, [Formula: see text], and pions. Similar signals were also seen in a neutron beam experiment at Serpukhov. These states, called U (3100), are tentatively explained as [Formula: see text] systems, i.e., [Formula: see text]. Such states were proposed more than a decade ago. New hyperon beam experiments in preparation at CERN and Fermilab will study these states, provided they exist. The proposed multiquark systems H = uuddss and [Formula: see text] are also discussed. One candidate for the decay H(2175) → Σ−p was observed in a propane buble chamber exposed to a proton beam. At Brookhaven National Laboratory, a missing-mass experiment in a high-intensity K− beam will search for the H, and the new hyperon beam experiments will search for inclusive production of both H and P.
An estimate for 12-quark cluster probabilities
Authors: Eich E. , Faissner H. , Kim B. R. , Rein D. , Rodenberg R.
Published: October 2017

Using quark density functions and the equivalent uniform model of nuclear physics, we give an estimate for 12-quark cluster probabilities as a function of the mass number A.
Quarks lourds, spectroscopie des
Authors: Bélanger G.
Published: October 2017

Two issues in [Formula: see text] spectroscopy are discussed. The calculation of the hadronic transitions of the triplet D state is reviewed showing that the radiative transitions remain the best signature for this state. A model, which was proposed to explain the anomalous spectra of the pions in the [Formula: see text] transition, is reviewed. The inclusion of a four-quark resonance in the [Formula: see text] channel, together with π+ π− final-state interactions, may explain the presence of two peaks in the [Formula: see text] spectrum.
The light-cone approach for the calculation of hadronic states
Authors: Girard Ralph , Langnau Alexander
Published: October 2017

We present an application of the recently proposed method of discretized light-cone quantization to quantum chromodynamics (QCD). We present the general method of light-cone quantization and point out its usefulness for the derivation of covariant integral equations for bound states. We then apply it to QCD and obtain the integral equation for the bound states in the valence sector of the mesons. The numerical solution of the integral equation shows a nice transition to the continuum. The conclusion summarizes the main results and discusses briefly what should be the next improvements of this method.
Skyrmions and effective Lagrangians
Authors: Loiseau B.
Published: October 2017

The need to model quantum chromodynamics (QCD) at low energy is emphasized. An outline of the1/NC expansion of QCD, for large NC, shows the deep link between the Skyrme effective Lagrangian and QCD. The Skyrme model, built from the nonlinear σ model plus a stabilizer term related to vector dominance, is briefly described. The model satisfies like QCD chiral symmetry. We illustrate how the gauged Wess–Zumino action demonstrates that the topological current can be identified with the baryon current. We recall how one can show that the topological soliton is a fermion for odd NC. An example of an effective Lagrangian, built from π and low-mass vector mesons, ω, ρ, and A1 fields, is given. It describes rather well low-energy meson and baryon physics. Predictions of effective Lagrangians of the Skyrme type on meson–meson, meson–baryon, and baryon–baryon scatterings at low energy are depicted. A two-phase chiral symmetric model, the chiral bag, is introduced. It contains an inner core of confined quarks and gluons surrounded by meson fields in the topological configuration of a Skyrmion. It can describe nuclei from the low- to the high-energy range.
The NN interaction and baryon structures
Authors: Harvey M.
Published: October 2017

A brief review is given of the author's research, with collaborators, on the nontopological chiral soliton model with interpretation in terms of the Nambu–Jona-Lasinio model and restrictions determined using the Dyakanov–Petrov ansatz. A discussion of early results on the effects of polarization of the Dirac sea with profile functions for mean fields is recorded.
A survey of the LEAR experimental programme
Authors: Duclos Jean
Published: October 2017

During the first period of operation of the low energy antiproton ring (LEAR) from 1983 to 1986, antiproton beams were supplied for several experiments at an intensity between 105 and [Formula: see text]. A first exploration was made of several subjects in physics, including [Formula: see text] and [Formula: see text]–nucleus interactions, [Formula: see text]–atoms, and various annihilation channels. After an improvement by a factor of 5 for the [Formula: see text] production at CERN in 1987, a new generation of experiments is expected to complete the previous studies and to cover new subjects concerning fundamental symmetries.
Réaction antiproton–proton aux basses énergies (Expérience PS173 au LEAR)
Authors: Brückner W. , Dworschak K. , Kneis H. , Paul S. , Povh B. , Treichel M. , Cujec B. , Döbbeling H. , Güttner F. , Majewski S. , Nomachi M. , Shibata T.-A. , Ransome R. D. , Walcher Th.
Published: October 2017

The antiproton–proton interaction has been studied by measuring the elastic scattering, charge exchange, and annihilation cross sections simultaneously, for beam momenta between 180 and 600 MeV/c. Here we describe the experimental setup and present partial results of the experiment. We have not found any evidence of the existence of the X (1935) resonance. It is possible to reproduce the elastic scattering and charge exchange differential cross sections with potential models. The Re f(0)/Im f(0) ratio shows an anomaly at low energy.[Journal Translation]
Looking for nonstrange dibaryonic resonances at intermediate energies
Authors: Lafrance Paul
Published: October 2017

The observable effects of perturbative quantum chromodynamics on hadronic reactions are quantitatively predictable in the f-matrix formalism. The resulting exotic six-quark states coupled to the nucleon–nucleon channel are described and their signatures identified. There is a good agreement between the predicted measurable signals and the available pp scattering data at medium energies.
Dileptons as a probe of excited nuclear matter
Authors: Gale Charles , Kapusta Joseph
Published: October 2017

The general features of dilepton production from nucleon–nucleon and nucleus–nucleus collisions are discussed. Estimates are made of the thermal production rates arising from incoherent nucleon–nucleon scattering and from two-pion annihilation. It may be possible to infer the pion dispersion relation in hot, dense nuclear matter by measuring the invariant mass distribution of back-to-back electrons and positrons in the center of mass frame in high energy nucleus–nucleus collisions. Comparison with recent data on p + Be → e+e−X at 4.9 GeV from the Bevalac is made.
Quelques aspects de la physique des collisions noyau–noyau à énergie ultra relativiste
Authors: Leroy Claude
Published: October 2017

We discuss the results of the measurements of the energy flow and multiplicity for the collisions of 16O and 32S with a set of target nuclei at an incident energy of 60 and 200 GeV/nucleon and 200 GeV/nucleon, respectively. These measurements have been performed at the European Organization for Nuclear Research (CERN) super proton synchroton by NA-34/HELIOS (high energy lepton and ion spectrometer), NA-35, NA-36, NA-38, and WA-80 in various pseudorapidity regions. The measurements of the transverse energy (ET) distributions provide an understanding of the concept of the stopping power and the estimates of the energy density reached. The energy densities reached in these collisions (~ 5 GeV/fm3) are at least an order of magnitude larger than the normal nuclear density (0.15 GeV/fm3) and are also in the region of the critical value of ~ 2.5 GeV/fm3 obtained from lattice gauge theory. [Formula: see text], obtained by combining the transverse energy and the multiplicity measurements, is compared with earlier results reported in cosmic-ray studies. The pT spectra of the charged particles and photons produced in these collisions are compared with the corresponding spectra measured in proton–nucleus collisions. The present situation suggests the study of new observables.
Production de J/ψ dans les collisions de proton, oxygène et soufre sur cibles lourdes, à 200 GeV/N
Authors: Baglin Ch. , Bussière A. , Guillaud J. P. , Staley F. , Ogren H. , Sonderegger P. , Baldit A. , Castor J. , Devaux A. , Fargeix J. , Felgeyrolles X. , Force P. , Fredj L. , Landaud G. , Borenstein S. , Busson Ph. , Charlot C. , Chaurand B. , Kluberg L. , Romana A. , Salmeron R. , Abreu M. C. , Barreira G. P. , Bordalo P. , Casaca A. , Ferraz A. , Ferreira R. , Gago J. M. , Gomes P. , Lourenco C. , Maio A. , Peralta L. , Pimenta M. , Ramos S. , Varela J. , Alimi M. , Bedjidian M. , Contardo D. , Descroix E. , Drapier O. , Grossiord J. Y. , Guichard A. , Haroutunian R. , Pizzi J. R. , Gerschel C. , Sinquin A. , Britz J. , Gorodetzky Ph. , Kraus L. , Linck I. , Racca C. , Cases R.
Published: October 2017

The production of J/ψ at 200 GeV/N, in proton, oxygen, and sulfur collisions with copper and uranium targets has been studied by the NA38 collaboration. When the energy density reached in the collisions increases a suppression of the muon pairs coming from the J/ψ disintegration, relative to those from the continuum, is observed. This relative suppression is stronger when the J/ψ transverse momentum is smaller.[Journal translation]
La physique de la matière hadronique à haute température telle que décrite par la chromodynamique quantique sur réseau espace–temps
Authors: Potvin Jean
Published: October 2017

The numerical simulation of quantum chromodynamics on a space–time lattice allows for the calculation of many properties of hadronic matter at high temperature in a direct and in a nonperturbative fashion. This paper will be a review of the calculation techniques and results published in the past 5 years. Among other things, I will discuss the order of the phase transition, the critical temperature, the force between heavy quarks, as well as the thermodynamics and the spectroscopy of the quark–gluon plasma.
Factorial moments in high-multiplicity events in 800 GeV proton interactions with AgBr nuclei
Authors: Shivpuri R. K. , Verma V. K.
Published: October 2017

The scaled factorial moments were investigated for secondary particles in high-multiplicity events produced by 800 GeV proton interactions with AgBr nuclei in a nuclear emulsion. The results show clear evidence for power-law behavior of scaled factorial moments. The variation of dimension as a function of order of the moment was also studied. The presence of phase transitions is not indicated from our data. From the behavior of the third-differential moment, we do not find any evidence for the clustering of particles in any pseudorapidity region.
Relaxation behaviour of Pb(Ni1/3Nb2/3)O3 ceramics
Authors: Sharma Seema , Sati R. , Choudhary R. N. P.
Published: October 2017

Polycrystalline samples of a cubic perovskite structure with an estimated 2.9% of a minor pyrochlore phase of Pb(Ni1/3,Nb2/3)O3 were synthesized by a high-temperature solid-state reaction technique. Dielectric studies show that the material is a good relaxor with a high dielectric constant. Diffuse phase transition through a wide Curie-temperature range was observed. The activation energy in a specified range of temperature for the material is estimated.
Electron impact excitation of He 21P in the presence of a nonresonant laser field
Authors: Wallbank B. , Holmes J. K. , Weingartshofer A.
Published: October 2017

We report experimental differential cross sections for inelastic scattering of electrons from helium atoms in the presence of an intense (~108 W cm−2) carbon dioxide laser. The cross sections for excitation of the 21P state of helium with the simultaneous absorption or emission of one laser quantum were measured over the incident electron energy range of 36–70 eV and scattering angles of 13–31°.
Radiative corrections in a nonlocal field theory
Authors: McKeon D. G. C.
Published: October 2017

We extend the notion of a scalar field [Formula: see text] to that of a field Φ(Xμ(σ)) so that the space-time point Xμ(σ) depends on a parameter [Formula: see text]. A straightforward generalization of the [Formula: see text] interaction is considered (viz: a [Formula: see text] theory). Radiative corrections in both cases can be evaluated using a technique involving quantum mechanical path integrals. For the [Formula: see text] model, this involves the classical Lagrange density [Formula: see text] (viz: that of a particle in the "proper time gauge") while for the [Formula: see text] model the Lagrange density [Formula: see text] (viz: that of a string in the "conformai gauge") must be considered. The two-point function is examined in both cases.
Generation of harmonics treated by a new integral equation method
Authors: Varró S , Ehlotzky F.
Published: October 2017

We derive a new integral equation for the nonperturbative evaluation of transition matrix elements of multiphoton processes at high laser field intensities. Our approach to the problem is partly based on the use of the Kramers–Henneberger transformation. As a specific example, we apply our method to the generation of harmonics by an electron in a short range potential, supporting a single bound state. We evaluate the rates R2m+1 for the odd harmonics created in this process for a set of specifically chosen parameters and we compare our results with presently available experimental data.
The low-field Hall mobility of an amorphous Hubbard model
Authors: Liu K. L.
Published: October 2017

We study the low-field Hall conductivity of a structurally disordered Hubbard model near half-filling and in the strong-correlation limit. The electronic transfer integral is taken to have a quasi-exponential form. We use a diagrammatic method to calculate the required current correlation function to second order in the inverse temperature and up to the eighth order in the electronic hopping. A positive Hall coefficient is obtained. The Hall mobility μH is calculated for various atomic concentrations at high temperatures. We find that μH is larger than the corresponding drift mobility μD. In contrast to the results obtained for the case of nearest-neighbor hopping on a simple cubic lattice, the Hall mobility of our model shows a weak thermal variation at high temperatures, but the ratio μH/μD increases approximately linearly with temperature. These differences are discussed.
Impulsive forces and the Heisenberg equations of motion for a particle in a box
Authors: Atkinson W. A. , Razavy M.
Published: October 2017

The quantum mechanical problem of a particle bouncing between two walls is formulated both in terms of the Heisenberg equations of motion and the Schrödinger equation. The reason for considering the Heisenberg equations is to understand the quantal nature of the impulsive forces. It is shown that these two formulations are compatible if, in addition to the classical impulsive forces, there are singular forces proportional to [Formula: see text] and [Formula: see text], i.e., forces of quantum origin. When these forces are added to the free-particle Hamiltonian then the total Hamiltonian is self-adjoint, and from it one can derive the boundary condition that must be imposed on the wave function. As an application of this formulation one can study the quantum mechanics of classical dynamical systems expressible as difference equations, e.g., the problem of a particle trapped between two walls moving relative to each other. The total Hamiltonian can also be used to study the question of the separability of the wave equation for such a motion.
Chiral symmetry-breaking and scaling properties of (2 + 1)-dimensional QED with four-fermion interactions
Authors: Kang Sin Kyu , Kim Jae Kwan
Published: October 2017

We study the chiral symmetry-breaking (2 + 1)-dimensional quantum electrodynamics with four-fermion interactions. Solving the Dyson–Schwinger equation with a boundary condition identical to an equation of state, we determine the phase diagram of this model and obtain a large anomalous dimension of the operator [Formula: see text]. By substituting a. symmetry-breaking solution in the equation of state, we find the critical exponents and show that they satisfy the hyperscaling laws. Some comments are given on the equation of hierarchy between the chiral symmetry-breaking scale and the fundamental scale in our model.
Traitement des données physiques : remarques sur la corrélation
Authors: Féménias Jean-Louis , Cheval Gérard
Published: October 2017

The interpretation of some latest very accurate physical data (like spectroscopical data) needs sophisticated models that often lead to correlation problems. The aim of this paper is to show that, when necessary, it is possible to work beyond correlation. The problems of numerical correlation with linear or nonlinear model or the problem of exact correlation with nonlinear models can be solved (applications are made in the real case of the red system of NbN). This latter situation leads to a new and interesting statistical point of view of the data treatment; however, computations are generally far longer than in the usual situation of weak correlation. The proposed point of view is compared with other recent works about the problems encountered in data reduction.
On the relation between thermodynamic temperature and kinetic energy per particle
Authors: Nettleton R. E.
Published: October 2017

In a computer simulation of a steady state in a fluid far from equilibrium, one needs to calculate temperature that is held constant. In classical thermodynamics and the local equilibrium approximation to nonequilibrium thermodynamics, T = TK ≡ (2/3Nκ) [Formula: see text], where [Formula: see text] is the kinetic energy, T is the temperature recorded by a thermometer in thermal equilibrium with the system. In extended thermodynamics, TK – T is of the order of squares of the heat and particle fluxes, shear-rate, or chemical reaction rate. Explicit estimates are made here of TK – T for binary isotopic diffusion, heat flow, steady Couette flow, and a classical model of a dissociation reaction. We use the maximum entropy formalism to calculate [Formula: see text] plus results from earlier extended thermodynamic treatments of these processes. In the cases considered, far enough from equilibrium for nonlinear effects, [Formula: see text]. In other cases where we do not know how to calculate thermodynamic forces, there are consistency tests of the assumption [Formula: see text].
Double differential cross sections in the electron impact ionization of helium
Authors: Brajamani S. , Singh N. Ranjit , Babuyaima M. , Mazumdar P. S.
Published: October 2017

The double differential cross sections for electron impact ionization of helium are evaluated in the framework of a distorted wave approximation that takes into account the effects of initial channel, final channel, and target distortion. The present results are in fair agreement with the measured values and rigorous DWBA (distorted-wave Born approximation) results of McCarthy and Zhang.
Schrödinger-Iike equations for spin measurements, states, and wave functions, based on the statistical approach of Guiasu
Authors: Slater Paul B.
Published: October 2017

Guiasu employed a statistical estimation principle to derive time-independent Schrödinger equations for the position but, as is usual, not the spin of a particle. Here, on the other hand, this principle is used to obtain Schrödinger-like equations for the spin but not the position of a particle. Steady states are described by continuous probability distributions, obtained by information-theoretic arguments, over spin measurements, states, and wave functions. These distributions serve as weight functions for orthogonal polynomials. Associated "wave functions," products of the polynomials and the square root of the weight function, satisfy differential equations, reducing to time-independent Schrödinger form at the point corresponding to the fully mixed spin-1/2 state.
A treatment of the equatorial magnetic Kerr effect using the 4 × 4 matrix formalism
Authors: Smet D. J. De
Published: October 2017

Expressions for the elements of the Jones matrix describing the reflection of polarized light from a material with an applied static magnetic field directed parallel to the intersection of the plane of incidence and the plane of the surface are derived using the 4 × 4 matrix formalism.
Celestial mechanics via quaternions
Authors: Vrbik Jan
Published: October 2017

The two-body perturbed problem is solved using a modified Kustaanheimo–Stiefel equation recast in a form suitable for perturbation-theory treatment. The power and elegance of the new technique is demonstrated by deriving major components of the Moon's motion in literally a few lines.
Singularities in the complex time plane and exactly solvable dynamical systems
Authors: Steeb W.-H. , Fatykhova Assia
Published: October 2017

A powerful tool in the study of nonlinear dynamical systems is the investigation of the singularity structure in the complex time plane. In most cases the singularity structure can only be found numerically. Here we give two models that can be solved exactly, i.e., we can give the singularities in the complex time plane. The two models play a central role in quantum mechanics. Then we compare them with the numerical study of the nonlinear differential equation.
Properties of the transition superoperator
Authors: Snider R. F. , Muga J. G.
Published: October 2017

Two different transition superoperators naturally arise in physical theories. First, there is the abstract transition superoperator that arises in the quantum Boltzmann equation and collision cross sections. Second, there is a transition superoperator that arises in the theory of spectral line broadening. The latter is parameterized by the frequency of the light being observed. At present the standard method of evaluating the effects of transition superoperators is through the use of transition operators. However, the connection between transition superoperators and operators has been the subject of controversy while the diversity of transition superoperators and operators can be confusing. This paper reviews the basic definitions and methods of relating these quantities, exemplifying these properties by using a separable potential with explicit calculations for a particular one-dimensional model. In this way the validity of previously presented abstract mathematical arguments is demonstrated explicitly.
Fast-neutron-scattering cross sections in soft nuclei: 56Fe
Authors: Cabezas R. , Lubian J.
Published: October 2017

The neutron elastic, inelastic, and total cross sections in 56Fe are calculated in the energy range 1–5 MeV using the coupled-channel method and statistical Hauser–Feshbach theory. Reduced matrix elements for coupled-channel calculations were computed in the frame of the Davydov–Chaban model (DCM) including nonaxial hexadecapole modes. The DCM calculations are compared with those using the harmonic vibrational model and we prove that the first model is appropriate for this nucleus. Good agreement with experimental data is reached.
Traitement semi-analytique du champ d'une source linéique de courant à proximité d'une bande conductrice mince
Authors: Attaf M. T. , Allab D.
Published: October 2017

The authors study the electromagnetic interaction, in steady state conditions, between a straight conductor carrying sinusoidal current, and a finite thickness metallic plate. First, they develop a solution in terms of magnetic vector potential. Then, they give a special attention to the numerical évaluation of the field components in their integral form. A high stability appropriate quadrature method is proposed. The effect of some parameters on field diffusion within the metallic plate is also examined.
Spectroscopic and thermochemical investigation of alkaline earth metal salts of 2-oximinopropionate
Authors: Apblett A.W. , Georgieva G.D. , Mague J.T.
Published: October 2017

Alkaline earth metal 2-oximinopropionates were prepared by the reaction of sodium 2-oximinopropionate with the respective metal nitrates or chlorides in water at room temperature. These compounds were characterized by infrared and multinuclear NMR spectroscopy and thermogravimetric analysis. The thermal decomposition of the salts occurs in the range 144-188°C and exhibits a trend towards lower temperature with increasing size of the cation. In all cases, the decomposition yields a metal carbonate. The molecular structure of calcium 2-oximinopropionate hydrate was determined by single-crystal X-ray crystallography. Crystal data: C6H10N2O7Ca, MW = 262.24 g/mol, triclinic, space group P͞1 (No.2), a = 8.954(1) Å, b = 9.3851(7) Å, c = 6.2445(7) Å, α = 97.209(8)°, β = 104.917(9)°, γ = 87.250(8)°, V = 503.0(2) Å3, Z = 2, Dcalc = 1.73 g cm–3, R = 0.03 and Rw = 0.04. Key words: crystal structure, alkaline earth, 2-oximinopropionate, thermal decomposition.
Synthesis and characterization of the mixed valence Cu(l)/Cu(ll) 3,5-bis(trifluoromethyl)-pyrazolate complex, [Cu(ll)2Cu(l)(F6dmpz)5]
Authors: Ehlert Martin K. , Storr Alan , Summers David A. , Thompson Robert C.
Published: October 2017

The reaction of molten 3,5-bis(trifluoromethyl)pyrazole (F6dmpzH) with copper metal shot under an atmosphere of dioxygen yields the green trimetallic mixed valence [Cu(II)2Cu(1)(F6dmpz)5]. Crystals of [Cu(II)2Cu(I)(F6dmpz)5] are triclinic, a = 9.0557(2), b = 9.6164(2), c = 11.8874(3) Å, α= 105.406(1)°, β = 112.317(1)°, γ = 90.662(1)°, Z= 1, space group P͞1. The crystal structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R value of 0.0538 for 2591 reflections with I≥2σ(I). Magnetic susceptibility studies over the range 2–300 K reveal strong antiferromagnetic exchange coupling between the two copper(II) centers. Fits of the magnetic data to the Bleaney-Bowers equation for two interacting S= ½ centers gives the exchange coupling constant J = –235 cm–1.

Key words: trimetallic, copper, 3,5-bis(trifluoromethyl)pyrazolates, X-ray structure, antiferromagnetism.
Influence of the antrum on the acid response to distension of the body of the stomach in dogs
Authors: Preshaw R. M.
Published: October 2017

In dogs with innervated antral pouches, distension of the body of the stomach caused an increase in acid output. This response was inhibited by acidification of the antral pouch, or vagal denervation of the antral pouch. In other dogs with denervated fundic pouches, distension of the body of the stomach failed to induce a significant response from the pouch, but was effective in stimulating the main stomach. These experiments indicate that the gastric secretory response to distension of the body of the stomach is enhanced by an antral mechanism.
Effect of vagotomy on the acid response to gastric distension
Authors: Preshaw R. M.
Published: October 2017

Distension of the body of the stomach, in conscious dogs with vagally innervated antral pouches, caused an increase in gastric acid output, and an increase in antral motor activity. Truncal vagotomy inhibited the acid response to distension, but had no effect on the antral motor response. Denervation of the antral pouch by separating it from the main stomach caused little further diminution in the response.
Effect of increased dietary phosphorus on calcium metabolism of young rats
Authors: Shah B. G. , Meranger J. C.
Published: October 2017

In a previous long-term experiment increased dietary phosphorus caused a decrease in bone mineral. The present experiment was undertaken to ascertain whether this effect was mediated through intestinal absorption of Ca and P or the turnover rate of bone mineral. Two groups of weanling rats which were injected with 45CaCl2 and fed stock diet for 9 days were fed diets containing 1.26% Ca, 0.55% P (group A) or 1.31% Ca, 1.15% P (group B) for about 5 weeks. Representative rats from each group were killed at 16, 26, 33, and 42 days, and blood, femur, and tibia collected. During the last week Ca and P balances were determined. The treatments did not affect the turnover rate of bone mineral, but the true absorption of calcium, allowing for the endogenous fecal loss, from diet A was 40% higher than from diet B. Although there was no difference in the P balance, the amount of Ca retained by rats in group A was 16% higher than the balance of Ca in group B, intake being approximately equal. The difference in femur Ca paralleled the Ca balance.
Pulmonary fate of histamine, isoproterenol, physalaemin, and substance P
Authors: Boileau Jean-Claude , Campeau Lucien , Biron Pierre
Published: October 2017

The biological inactivation of four vasodilator agents during a single passage through the pulmonary circulation was studied by means of an assay based on systemic depressor responses. Isoproterenol was tested in humans undergoing cardiac catheterization and in anesthetized normal dogs. Histamine and physalaemin were tested in anesthetized normal rats and dogs; substance P was tested in rats. The degree of inactivation of these four vasodilator agents was either negligible or small, rarely exceeding 15%. It is concluded that the lung is not an important site for the removal of these substances from the circulation. The small degree of pulmonary inactivation of histamine suggests that it could play some role as a "circulating" hormone. Unlike bradykinin, the "tachykinins" physalaemin and substance P undergo little pulmonary inactivation. The absence of lung inactivation of isoproterenol explains its entry into the systemic circulation when given by inhalation.
Effect of radiation on lecithin metabolism, surface activity, and compliance of rat lung
Authors: Naimark A. , Newman D. , Bowden D. H.
Published: October 2017

The effect of ionizing radiation on lecithin metabolism, surface activity, and compliance of the lung was studied in rats. At intervals of 1 to 4 months after irradiation of the right hemithorax (3000 R, single dose) exposed lungs were compared with contralateral shielded lungs and with the right lungs of nonirradiated control rats. Four months after exposure, irradiated lungs did not differ in DNA content from controls but exhibited decreased lecithin content, depressed incorporation of palmitate-1-14C into lecithin in vitro, and a decrease in the percentage of palmitic acid in the lecithin fraction. Changes in other phospholipids were qualitatively similar. The stability of bubbles expressed from the cut surface of irradiated lungs decreased progressively with time, indicating impaired surface activity of the lung-lining layer. This was associated with a progressive decrease in compliance of the lung. Electron microscopy revealed no qualitative changes in the alveolar epithelial cells. Morphologic evidence of injury was most prominent in the capillaries and could be detected before changes in phospholipid content, surface activity, and compliance. Our studies indicate that irradiation of the lung is associated with alterations in lecithin content, in surface activity, and in compliance of the lung, and suggest that such changes are secondary to endothelial damage rather than a reflection of a primary effect on surface activity.
The static elastic properties of carotid arteries from fetal sheep
Authors: Roach Margot R.
Published: October 2017

Simultaneous measurements of volume, pressure, and length were made on 91 cylindrical segments of isolated carotid arteries from 61 fetal sheep of 85 to 141 days gestation (term = 147 days). Tension–length curves were calculated from these data by utilizing the Law of Laplace (tension = pressure × radius). Analysis of the curves suggests that the elastance (tension/strain) increased exponentially with age in all regions of the curve (i.e. for elastin, collagen, and in the physiological range). The unstretched radius, the wall thickness of non-distended sections of the arteries, and the interconnections or 'links' between collagen fibers all appeared to increase linearly with age. Histological sections indicate that these arteries develop an external elastic membrane between 85 and 92 days of gestation. With maturation, the medial elastic lamellae become less organized owing to ingrowth of collagen and muscle. Weight may be more important than age in assessing maturity since arteries from twins of different weights behaved quite differently. The mathematical problems encountered in assessing geometrical relationships over restricted regions of curves are discussed in detail.
The identification of acetyl-l-carnitylcholine in rat brain extracts and the comparison of its cholinomimetic properties with acetylcholine
Authors: Hosein E. A. , Kato A. , Vine E. , Hill A. M.
Published: October 2017

Acetyl-l-carnitylcholine (l-ACCh) was identified in rat brain extracts on paper chromatograms developed in butanol–water for 138 h. l-ACCh was also identified in brain extracts fractionated on t.l.c. plates and on Sephadex G-10 columns. In every instance l-ACCh was separated from the acetylcholine (ACh) present and the ACh-like activity of l-ACCh was about 20% of the total activity in the extract. Both l-ACCh and ACh were found to be inseparable in a variety of chromatographic systems including electrophoresis. Treatment of these choline esters with cholinesterases showed that while true acetylcholinesterase hydrolyzed both l-ACCh and ACh, pseudocholinesterase destroyed only ACh. On a molar basis, the ACh-like activity of ACCh is one-half that of ACh on both the guinea pig ileum and frog rectus preparations. Like ACh, the ratio of the nicotinic to muscarinic potency of l-ACCh is unity. Mixtures of l-ACCh and ACh show summation of ACh-like activity on both the guinea pig ileum and frog rectus preparations.
Tolerance of unacclimated and cold-acclimated rats to exercise in the cold: serum, red and white muscle enzymes, and histological changes
Authors: Dieter M. P. , Altland P. D. , Highman B.
Published: October 2017

Unacclimated and cold-acclimated rats were exercised for 3 h, 5 h, or 9 h in a cold room maintained at 1.7 °C. The cold-acclimated rats tolerated these exercise periods, but two-thirds of the unacclimated rats died during 9 h exercise. In red and white muscle the intermediate exercise interval (5 h) induced significantly greater increases in the activities in muscle of creatinephosphokinase and glycolytic enzymes of unacclimated rats, while during 9 h exercise enzyme activity declined in muscles of unacclimated rats and increased in cold-acclimated ones. The rise in serum enzyme activity during exercise was consistently greater in unacclimated than in cold-acclimated rats. Apparently the reduction in exercise tolerance was associated with and may have been in part due to loss of enzyme content and activity in muscles. Collectively, these and other biochemical responses suggested that homeostatic mechanisms had been exhausted in the rats dually stressed by cold exposure and exercise. Except for the activities of aldolase and the ratio of lactic dehydrogenase to alpha-glycerophosphate dehydrogenase, those enzymes associated with "aerobic" function (transaminases) showed the predominant changes in red muscle, and those associated with "anaerobic" function (glycolytic enzymes) the predominant changes in white muscle. The greater responses of the glycolytic enzymes in a predominantly "aerobic" tissue suggest that the biochemical adaptability of red muscle is greater than that of white muscle.
Etude de l'influence de jeûnes périodiques sur la croissance, la glycémie, quelques caractéristiques du métabolisme hépatique et la composition corporelle du poulet
Authors: Simon J. , Blum J. C.
Published: October 2017

Le poulet en croissance est soumis à des inanitions totales périodiques. L'animal alterne entre des phases de jeûne (diète hydrique) et d'alimentation libre, ces deux phases définissant une "période". Dans tous les cas, le développement pondéral est ralenti, le ralentissement est d'autant plus marqué que la durée totale du jeûne est plus grande. Mais la croissance varie également avec la longueur de la période : pour les périodes les plus courtes, le gain de poids est plus important. Pendant les phases d'alimentation, la vitesse de croissance et l'efficacité alimentaire sont accrues. Les animaux manifestent une hyperphagie qui augmente en cours d'expérience, surtout lorsque la période est courte. Pendant la séquence d'inanition, les pertes de poids dépendent seulement de la taille des animaux mais il faut noter que la glycémie de jeûne est plus faible dans tous les lots entraînés à l'alimentation discontinue. Le métabolisme hépatique est modifié: hypertrophie pendant les phases d'alimentation, déplétion pendant le jeûne. De plus, la glycogénogénèse est stimulée. Le dépôt de lipides corporels est accru mais seulement lorsque les animaux sont alimentés plus longtemps qu'ils ne jeûnent. Par ailleurs la protéinogénèse reste constante.
Effect of Two Types of Feed Restriction, Intermittent Total Starvation or Intermittent Protein Starvation, on Growth, Lipogenesis, and Fatty Acid Composition of Liver and Adipose Tissues in Chicks
Authors: Simon J. , Brisson G. J.
Published: October 2017

Seventy-two 4-week-old Arbor Acres male chicks were divided into four groups: group ITS 1-1 was intermittently starved for 1 day and fed a balanced diet ad libitum for the next day throughout the experiment; group ITS 2-4 was intermittently starved for 2 days and then fed ad libitum for the next 4 consecutive days; group IPS 1-1 was alternately fed a protein-free diet for 1 day and a balanced diet for the next day; a fourth group was used as control and fed ad libitum throughout. The experiment lasted 50 days. Growth rate in all restricted groups was slower than in control birds but within the restricted groups there was no difference (P = 0.05). Hyperphagia was observed in all restricted groups, but was insufficient to completely prevent the growth retardation induced by the feed restriction schedules. Fat deposition, as measured by weight of abdominal tissue, considerably increased in the protein-restricted birds, when compared to all other groups. Lipogenesis, measured in vitro with sodium acetate-1-14C, was stimulated by both types of feed restriction, but to a greater extent by the ITS treatments. In liver and abdominal fat tissues of all restricted birds, oleic acid was increased and linoleic acid decreased. This might be the result of an increased endogenous fatty acid synthesis.