bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Models for the Design of the LAPLAS Experiment
Authors: Piriz A. R. , Tahir N. A. , López Cela J. J. , Cortázar O. D. , Serna Moreno M. C. , Temporal M. , Hoffmann D. H. H. 
Published: June 2007

AbstractWe review the theoretical activity at the University of Castilla‐LaMancha directed to the design of the LAPLAS (Laboratory of Planetary Sciences) experiment in the framework of the HEDgeHOB international collaboration. We have developed analytical models for the different phases of LAPLAS, including models for the implosion of the cylindrical shell target, for the generation of an annular focal spot by means of a high‐frequency wobbler system and for the hydrodynamic instabilities that could affect the performance of the target implosion. These models have been complemented with one and two‐dimensional numerical simulations and such a combination have allowed us to have a powerful tool available for the design of the experiments as well as for the interpretation of their results. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Survey of Theoretical Work for the Proposed HEDgeHOB Experimental Schemes: HIHEX and LAPLAS
Authors: Tahir N. A. , Piriz A. R. , Shutov A. , Lomonosov I. V. , Gryaznov V. , Wouchuk G. , Deutsch C. , Spiller P. , Fortov V. E. , Hoffmann D. H. H. , Schmidt R. 
Published: June 2007

AbstractThis paper presents a review of the theoretical work that has resulted in a scientific proposal on studies of High‐Energy‐Density (HED) states in matter using intense beams of energetic heavy ions that will be available at the future Facility for Antiprotons and Ion Research (FAIR) at Darmstadt [W.F. Henning, Nucl. Inst. Meth B 24 (2003) 725‐729]. The proposal is named HEDgeHOB that stands for High Energy Density Matter Generated by Heavy Ion Beams. Two experimental schemes have been worked out for the HEDgeHOB experimental proposal, namely, HIHEX and LAPLAS. The first scheme allows for studies of HED states by isochoric and uniform heating of matter by an intense heavy ion beam that is followed by isentropic expansion of the heated material. Numerical simulations have shown that using the beam parameters that will be available at the FAIR, one can access all the interesting physical states of HED matter including an expanded hot liquid state, twophase liquid‐gas region, critical point parameters and strongly coupled plasmas for all the materials of interest. The second scheme involves a low‐entropy compression of a test material like hydrogen that is enclosed in a cylindrical shell of a high‐Z material like gold or lead. The target can be driven by a hollow or a circular beam. This compression scheme relies on multiple shock reflection between the hydrogen‐gold (lead) boundary and the cylinder axis. The hydrodynamic stability of the LAPLAS target has also been analyzed that shows that the implosion is completely stable to Rayleigh‐Taylor and Richtmyer‐Meshkov instabilities. LAPLAS implosion using a hollow beam is suitable for studying the problem of hydrogen metallization whereas the one employing a circular focal spot leads to physical conditions that are expected to exist in the interiors of the giant planets. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recombination Processes in Laser Produced Dense Cluster Plasma
Authors: Krainov V. P. , Sofronov A. V. 
Published: June 2007

AbstractVarious mechanisms of recombination of electrons with multiply charged atomic ions in atomic clusters irradiated by superintense femtosecond laser pulses are discussed. Some of the recombination mechanisms are shown to take a time considerably longer than the laser pulse duration and, hence, they can develop only in a homogeneous, fairly rarefied cluster plasma after pulse termination. All autoionization states of multiply charged ions in a dense cluster plasma have been found to be destroyed by the Holtsmark electric field. Therefore dielectric recombination does not take place in irradiated clusters during the laser pulse. Only collision recombination electron ‐ ion ‐ electron occurs effectively in dense cluster plasma due to high charge multiplicity of produced atomic ions inside the cluster. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exchange Correlation of Particles and Quantum Collision Integral in a Non‐Ideal Plasma with Polarization
Authors: Belyi V. V. , Kukharenko Yu. A. 
Published: June 2007

AbstractStarting with the quantum BBGKY‐hierarchy for the distribution functions, we have obtained the quantum non‐Marcovian kinetic equation including the dynamical screening of the interaction potential, which exactly takes into account the exchange scattering in the plasma. The collision integral is expessed in terms of the Green function of the linearized Hartree ‐ Fock equation.This quantum kinetic equation satisfies the law of total energy conservation with account of the polarization and exchange interaction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamic and Transport Properties of Nonideal Complex Plasmas on the Basis of Pseudopotential Models
Authors: Ramazanov T. S. , Dzhumagulova K. N. , Gabdullin M. T. , Akbarov A. Zh. , Nigmetova G. N. 
Published: June 2007

AbstractThe thermodynamic and transport properties of dense semiclassical plasmas were investigated on the basis of pseudopotential models taking into account quantum‐mechanical effects at short distances and screening effects at large distances. The equation of state was calculated using correlation functions. The cross sections, the composition of the aluminum plasma and the electrical conductivity of the hydrogen plasma are obtained on the basis of conventional methods. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical Properties and One‐Particle Spectral Function in Non‐Ideal Plasmas
Authors: Fortmann C. , Röpke G. , Wierling A. 
Published: June 2007

AbstractA basic concept to calculate physical features of non‐ideal plasmas, such as optical properties, is the spectral function which is linked to the self‐energy. We calculate the spectral function for a non‐relativistic hydrogen plasma in GW ‐approximation. In order to go beyond GW approximation, we include self‐energy and vertex correction to the polarization function in lowest order. Partial compensation is observed. The relation of our approach to GW and GW Γ calculations in other fields, such as the band‐structure calculations in semiconductor physics, is discussed. From the spectral function we derive the absorption coefficient due to inverse bremsstrahlung via the polarization function. As a result, a significant reduction of the absorption as compared to the Bethe‐Heitler formula for bremsstrahlung is obtained. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Equation of State for Dense Hydrogen and Plasma Phase Transition
Authors: Holst B. , Nettelmann N. , Redmer R. 
Published: June 2007

AbstractWe calculate the equation of state of dense hydrogen within the chemical picture. Fluid variational theory is generalized for a multi‐component system of molecules, atoms, electrons, and protons. Chemical equilibrium is supposed for the reactions dissociation and ionization. We identify the region of thermodynamic instability which is related to the plasma phase transition. The reflectivity is calculated along the Hugoniot curve and compared with experimental results. The equation‐of‐state data is used to calculate the pressure and temperature profiles for the interior of Jupiter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of the Temperature‐Anisotropy Relaxation Time of the Earth's Magnetosheath
Authors: Meister C.‐V. , Besser B. , Lebedeva V. 
Published: June 2007

AbstractIn the present paper, a short review of plasma waves and turbulence in the Earth's bow shock and magnetosheath is given. Magnetohydrodynamic models which are recently applied for the magnetosheath are presented. Further, results for the relaxation of the proton temperature‐anisotropy in the magnetosheath by proton pitch‐angle diffusion obtained for two different magnetohydrodynamic models are discussed. It is pointed out that the relaxation time is determined by the varying strength of the excitation of ion‐cyclotron and mirror waves in the different magnetosheath regions. Besides, there seems to be a background wave transfer from the solar wind into the magnetosheath. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shielding and Interaction of Dust Particles in Non‐Equilibrium Plasma
Authors: Starostin A. N. , Filippov A. V. , Pal A. F. , Momot A. I. , Zagorodny A. G. 
Published: June 2007

AbstractThis paper investigates the interaction of two dust particles in non‐equilibrium plasma at elevated pressures. On the basis of asymptotic shielding theory resulting in two‐exponential shielding the electrostatic energy of two charged fine particles is determined. The electrostatic energy dependence on interparticle distance proves to have a minimum as in an equilibrium plasma. The electrostatic interaction force of the particles is calculated. This force is proved to be non‐symmetric: for different charges the force acting on one dust particle was not equal to the force acting on the other dust particle. This is due to non‐symmetric charge separation in the vicinity of different charged dust particles. It is stated that likely charged particles repel each other and at the closest approach the attraction is only possible. Relationships to determine the modified nonideality parameter for the interaction potential, which consisted of two exponents with different shielding lengths, were obtained. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dinuclear (Arene)ruthenium Complexes Containing a Chiral‐at‐Phosphorus Phosphanido Bridge
Authors: Tschan Mathieu J.‐L. , Süss‐Fink Georg , Chérioux Frédéric , Therrien Bruno 
Published: June 2007

AbstractThe unsaturated diruthenium cation [(η6‐C6Me6)(η6‐p‐iPrMeC6H4)Ru2(μ2‐H)3]+ reacts with PPh2(CH2)3Ph to give the phosphanido complex [(η6‐C6Me6)(η6‐p‐iPrMeC6H4)Ru2{μ2‐PPh(CH2)3Ph}(μ2‐H)2]+ (1), which contains a stereogenic phosphorus atom in the bridge, and benzene. Heating of 1 in bromobenzene gives the first chiral‐at‐phosphorus diruthenium complex [(η6‐C6Me6)Ru2{μ2‐PPh(CH2)3‐η6‐Ph}(μ2‐Br)2]+ (3) due to the replacement of the p‐cymene ligand by the phenyl group at the pendant arm and hydrido bridges by bromido bridges. The single‐crystal X‐ray structure analysis of [3][BF4] reveals a racemic mixture of both enantiomers (RP)‐3 and (SP)‐3 in the crystal. Similarly, the reaction of [(η6‐C6Me6)(η6‐p‐iPrMeC6H4)Ru2(μ2‐H)3]+ and the enantiopure phosphane (R)‐PPh2(CH2)2CHMePh yields the complex [(η6‐C6Me6)(η6‐p‐iPrMeC6H4)Ru2{μ2‐(R)‐PPh(CH2)2CHMePh}(μ2‐H)2]+ (4) as a mixture of diastereomers. An optically active mixture (de = 4 %) of phosphanido‐bridged complexes [(η6‐C6Me6)Ru2{μ2‐(R)‐PPh(CH2)2CHMe‐η6‐Ph}(μ2‐Br)2]+ (6), containing the (RC,SP) and (RC,RP) diastereomers, is obtained upon heating of 4 in bromobenzene. The molecular structure of [6][BF4] reveals that the two diastereomers (RC,SP)‐6 and (RC,RP)‐6 exist as two conformers. The non‐chiral‐at‐phosphorus analogues [(η6‐C6Me6)2Ru2{μ2‐PPh(CH2)3Ph}(μ2‐H)2]+ (2) and [(η6‐C6Me6)2Ru2{μ2‐(R)‐PPh(CH2)2CHMePh}(μ2‐H)2]+ (5) have also been synthesized and structurally characterized by single‐crystal X‐ray structure analyses of [2][BF4] and [5][BF4].(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An improved hybrid Cartesian/immersed boundary method for fluid–solid flows
Authors: Gao Tong , Tseng Yu‐Heng , Lu Xi‐Yun 
Published: June 2007

AbstractAn improved hybrid Cartesian/immersed boundary method is proposed based on ghost point treatment. A second‐order Taylor series expansion is used to evaluate the values at the ghost points, and an inverse distance weighting method to interpolate the values due to its properties of preserving local extrema and smooth reconstruction. The present method effectively eliminates numerical instabilities caused by matrix inversion and flexibly adopts the interpolation in the vicinity of the boundary. Some typical fluid–solid flows, including viscous flow past a circular cylinder, a sphere, two cylinders in a side‐by‐side arrangement, and an array of 18 staggered cylinders, are examined. These benchmark simulations reasonably indicate the reliability and capability of the present method. Copyright © 2007
John Wiley & Sons, Ltd.
Prediction of wave pattern and wave resistance of surface piercing bodies by a boundary element method
Authors: Bal Sakir 
Published: June 2007

AbstractAn iterative boundary element method, which was originally developed for both two‐ and three‐dimensional cavitating hydrofoils moving steadily under a free surface, is modified and extended to predict the wave pattern and wave resistance of surface piercing bodies, such as ship hulls and vertical struts. The iterative nonlinear method, which is based on the Green theorem, allows the separation of the surface piercing body problem and the free‐surface problem. The free‐surface problem is also separated into two parts; namely, left and right (with respect to x axis) free‐surface problems. Those all (three) problems are solved separately, with the effects of one on the other being accounted for in an iterative manner. The wetted surface of the body (ship hull or strut, including cavity surface if exists) and the left and right parts with respect to x axis of free surface are modelled with constant strength dipole and constant strength source panels. In order to prevent upstream waves, the source strengths from some distance in front of the body to the end of the truncated upstream boundary are enforced to be zero. No radiation condition is enforced for downstream and transverse boundaries. A transverse wave cut technique is used for the calculation of wave resistance. The method is first applied to a point source and a three‐dimensional submerged cavitating hydrofoil to validate the method and a Wigley hull and a vertical strut to compare the results with those of experiments. Copyright © 2007 John Wiley & Sons, Ltd.
A higher‐order predictor–corrector scheme for two‐dimensional advection–diffusion equation
Authors: Man Chuanjian , Tsai Christina W. 
Published: June 2007

AbstractA higher‐order accurate numerical scheme is developed to solve the two‐dimensional advection–diffusion equation in a staggered‐grid system. The first‐order spatial derivatives are approximated by the fourth‐order accurate finite‐difference scheme, thus all truncation errors are kept to a smaller order of magnitude than those of the diffusion terms. Therefore, there is no need to add an artificial diffusion term to balance the unwanted numerical diffusion. For the time derivative, the fourth‐order accurate Adams–Bashforth predictor–corrector method is applied. The stability analysis of the proposed scheme is carried out using the Von Neumann method. It is shown that the proposed algorithm has good stability. This method also shows much less spurious oscillations than current lower‐order
accurate numerical schemes. As a result, the proposed numerical scheme can provide more accurate results for long‐time simulations. The proposed numerical scheme is validated against available analytical and numerical solutions for one‐ and two‐dimensional transport problems. One‐ and two‐dimensional numerical examples are presented in this paper to demonstrate the accuracy and conservative properties of the proposed algorithm by comparing with other numerical schemes. The proposed method is demonstrated to be a useful and accurate modelling tool for a wide range of transport problems. Copyright © 2007 John Wiley & Sons, Ltd.
Exploring the role of context‐dependent hippocampal activity in spatial alternation behavior
Authors: Ainge James A. , van der Meer Matthijs A.A. , Langston Rosamund F. , Wood Emma R. 
Published: June 2007

AbstractIn a continuous T‐maze spatial alternation task, CA1 place cells fire differentially on the stem of the maze as rats are performing left‐ and right‐turn trials (Wood et al. (2000) Neuron 27:623–633). This context‐dependent hippocampal activity provides a potential mechanism by which animals could solve the alternation task, as it provides a cue that could prime the appropriate goal choice. The aim of this study was to examine the relationship between context‐dependent hippocampal activity and spatial alternation behavior. We report that rats with complete lesions of the hippocampus learn and perform the spatial alternation task as well as controls if there is no delay between trials, suggesting that the observed context‐dependent hippocampal activity does not mediate alternation behavior in this task. However lesioned rats are significantly impaired when delays of 2 or 10 s are interposed. Recording experiments reveal that context‐dependent hippocampal activity occurs in both the delay and no‐delay versions of the task, but that in the delay version it occurs during the delay period, and not on the stem of the maze. These data are consistent with a role for context‐dependent hippocampal activity in delayed spatial alternation, but suggest that, according to specific task demands and memory load, the activity may be generated by different mechanisms and/or in different brain structures. © 2007 Wiley‐Liss, Inc.
Processing idiothetic cues to remember visited locations: Hippocampal and vestibular contributions to radial‐arm maze performance
Authors: Allen Kevin , Potvin Olivier , Thibaudeau Geneviève , Doré François Y. , Goulet Sonia 
Published: June 2007

AbstractThis research examined whether rats can use idiothetic cues to form spatial memories in the radial‐arm maze (RM) and whether the hippocampus is involved in such ability. A possible contribution of the vestibular system to RM performance was also investigated. Rats with excitotoxic hippocampal lesions and sham‐operated controls were trained on two versions of the RM task. In the Light condition, a unique visual insert was apposed on each arm floor and rats could choose which arm to enter next by relying on visual and/or idiothetic stimuli. In the Dark condition, the task was administered in darkness and success required processing of idiothetic cues to remember visited locations on the maze. In experiment 1, the performance of lesioned rats was impaired in the Light condition, but both control and lesioned rats learned to avoid already visited arms. In the Dark condition, the performance of controls improved over time whereas a severe deficit was observed in rats with hippocampal lesions. Thus, control rats, but not hippocampal lesioned rats, can form spatial memories by processing idiothetic inputs. Experiment 2 showed that vestibular lesions disrupt performance in both the Light and the Dark conditions and confirmed that rats use idiothetic information, especially vestibular cues, while navigating in the RM. Therefore, cues generated during locomotion play an important role in hippocampal‐dependent spatial memory. © 2007 Wiley‐Liss, Inc.
Efficient tests of long‐run causation in trivariate VAR processes with a rolling window study of the money–income relationship
Authors: Hill Jonathan B. 
Published: June 2007

AbstractThis paper develops a simple sequential multiple‐horizon non‐causation test strategy for trivariate VAR models (with one auxiliary variable). We apply the test strategy to a rolling window study of money supply and real income, with the price of oil, the unemployment rate and the spread between the Treasury bill and commercial paper rates as auxiliary processes. Ours is the first study to control simultaneously for common stochastic trends, sensitivity of test statistics to the chosen sample period, null hypothesis over‐rejection, sequential test size bounds, and the possibility of causal delays. Evidence suggests highly significant direct or indirect causality from M1 to real income, in particular through the unemployment rate and M2 once we control for cointegration. Copyright © 2007 John Wiley & Sons, Ltd.
The policy environment and relative price efficiency of Egyptian private sector manufacturing: 1987/88–1995/96
Authors: Getachew Lullit , Sickles Robin C. 
Published: June 2007

AbstractWe study the impact of policy and institutional constraints, and reforms undertaken to remedy them, on relative price efficiency and cost of the private manufacturing sector of Egypt. We undertake this study using a generalized cost function, which subsumes the standard neoclassical cost function as a special case. This approach allows us to assess the impact of such constraints, which include labor market, energy and financial sector ones, on relative prices and the structure of production, including factor demands, shares and cost. Our findings indicate the presence of substantial distortions in relative prices, and hence on cost, due to the policy environment. We also find improvements in relative price efficiency and cost performance as a result of policy reforms initiated to remove the constraints. Copyright © 2007 John Wiley & Sons, Ltd.
Small‐sample bias in synthetic cohort models of labor supply
Authors: Devereux Paul J. 
Published: June 2007

AbstractThis paper investigates small‐sample biases in synthetic cohort models (repeated cross‐sectional data grouped at the cohort and year level) in the context of a female labor supply model. I use the Current Population Survey to compare estimates when group sizes are extremely large to those that arise from randomly drawing subsamples of observations from the large groups. I augment this approach with Monte Carlo analysis so as to precisely quantify biases and coverage rates. In this particular application, thousands of observations per group are required before small‐sample issues can be ignored in estimation and sampling error leads to large downward biases in the estimated income elasticity. Copyright © 2007 John Wiley & Sons, Ltd.
A longitudinal study of mental health consumer/survivor initiatives: Part V–Outcomes at 3‐year follow‐up
Authors: Nelson Geoffrey , Ochocka Joanna , Janzen Rich , Trainor John , Goering Paula , Lomotey Jonathan 
Published: June 2007

AbstractThe objective of this study was to evaluate the impacts of participation in mental health Consumer/Survivor Initiatives (CSIs), organizations run by and for people with mental illness. A nonequivalent comparison group design was used to compare three groups of participants: (a) those who were continually active in CSIs over a 36‐month period (n = 25); (b) those who had been active in CSIs at 9‐ and 18‐month follow‐up periods, but who were no longer active at 36 months (n = 35); and (c) a comparison group of participants who were never active in CSIs (n = 42). Data were gathered at baseline, 9‐, 18‐, and 36‐month follow‐ups. The three groups were comparable at baseline on a wide range of demographic variables, self‐reported psychiatric diagnosis, service use, and outcome measures. At 36 months, the continually active participants scored significantly higher than the other two groups of participants on community integration, quality of life (daily living activities), and instrumental role involvement, and significantly lower on symptom distress. No differences between the groups were found on other outcome measures. Improvements in 36‐month outcomes for people with mental illness who participated in CSIs suggest the potential value of these peer support organizations. Further research is needed to determine the replicability of these positive findings. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 655–665, 2007.