bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma Heating and Diffusion in Stochastic Fields
Authors: Puri S.
Published: December 2004

Motion of electrons in a static magnetic field and a transverse random electric field is analyzed. A plasma consisting of ``test particles'' is found to extract energy from the electric field. Heating proceeds linearly in time, and the plasma retains a Maxwellian velocity distribution. The heating and diffusion rates have been computed in terms of the power spectrum of the fluctuating electric fields of arbitrary strength.
Burning-Wave Speed Enhancement by Electric Fields
Authors: Fowler R. G. , Corrigan S. J. B.
Published: December 2004

A significant relation has been observed between flame reaction rates and the intensity of an applied electric field in which the flame is immersed, which seems to establish the importance of electrons as reaction promoting agents.
Onset of Thermal Instability in a Horizontal Circular Cylinder
Authors: Sherman Michael
Published: December 2004

The classical Rayleigh thermal-stability problem of an infinite horizontal fluid layer heated from below is extended to the case of a fluid confined within a rigid, horizontal circular cylinder whose wall is nonuniformly heated. The temperature distribution on the wall is specified such that, in the quiescent state, a constant temperature gradient in the fluid is established in the direction of the body force. The governing perturbation equations form a self-adjoint eigenvalue problem for the critical Rayleigh number (the stability criterion). Two different variational principles are presented, each equivalent to the eigenvalue problem. Using these principles, two approximate methods are developed for calculating upper bounds to the critical Rayleigh number. It is found that the critical Rayleigh number for the cylindrical configuration (based on a unit diameter) is about 3.8 times that for the horizontal-layer configuration (based on a unit height). The value for the cylinder is considerably lower than values calculated in previous analyses.
Self-Consistent-Field Approach to Nonstationary Turbulence
Authors: Herring J. R.
Published: December 2004

The self-consistent-field method proposed earlier [J. R. Herring, Phys. Fluids 8, 2219 (1965)] to treat stationary turbulence is generalized to include the case of time dependent turbulence. The predictions of the method are compared to exact and direct-interaction solutions for simple model systems consisting of several interacting shear waves. The main features of the system's approach to equilibrium are correctly predicted by the method. The predicted single-mode-energy spectrum has small spurious oscillations, which result from truncating the perturbation series at second order. These oscillations are somewhat larger in amplitude than those that would result from using the direct-interaction approximation for the same system.
Axisymmetric Minimum Average B Configuration of a Triply Connected System
Authors: Yoshikawa S. , Christensen U. R.
Published: December 2004

An axially symmetric toroidal device with one floating conductor which has both minimum average B and high-shear properties is described. Both magnetic well and shear can approach the theoretical maximum in this device.
Faraday Rotation Measurement of Trapped Magnetic Fields in a Thetapinch Plasma
Authors: Bogen P. , Rusbüldt D.
Published: December 2004

Using a 3.39-μ He-Ne laser, trapped fields of −4 to +8 kG were measured in a 45-kG driving field (β > 0.97) when no bias field was applied. With antiparallel bias field, no trapped field reversal was observed at high densities.
Velocity Space Diffusion from Weak Plasma Turbulence in a Magnetic Field
Authors: Kennel C. F. , Engelmann F.
Published: December 2004

The quasi-linear velocity space diffusion is considered for waves of any oscillation branch propagating at an arbitrary angle to a uniform magnetic field in a spatially uniform plasma. The space-averaged distribution function is assumed to change slowly compared to a gyroperiod and characteristic times of the wave motion. Nonlinear mode coupling is neglected. An H-like theorem shows that both resonant and nonresonant quasi-linear diffusion force the particle distributions towards marginal stablity. Creation of the marginally stable state in the presence of a sufficiently broad wave spectrum in general involves diffusing particles to infinite energies, and so the marginally stable plateau is not accessible physically, except in special cases. Resonant particles with velocities much larger than typical phase velocities in the excited spectrum are scattered primarily in pitch angle about the magnetic field. Only particles with velocities the order of the wave phase velocities or less are scattered in energy at a rate comparable with their pitch angle scattering rate.
Negative Mass Instability
Authors: Landau Ronald W. , Neil V. Kelvin
Published: December 2004

A canonical formalism has been developed for the description of the negative mass instability. The formalism has been applied to the formulation of a kinetic equation which is solved by the method of characteristics (or integration over orbits). It is found that a spread in betatron oscillation amplitudes contributes to stability, in addition to the spread in the canonical angular momentum. The negative mass instability equation for two streams is also obtained, and the result is the same as though each stream were present separately. It is also shown that the linear two-stream equation does not apply for a circular beam geometry; instead, the negative mass instability two-stream equation applies.
Plasma Oscillations Perpendicular to a Weak Magnetic Field
Authors: Baldwin D. E. , Rowlands G.
Published: December 2004

The propagation of electrostatic waves perpendicular to a uniform magnetic field, the so-called Bernstein modes, are discussed. It is shown, in the limit as the strength of the magnetic field approaches zero, that these modes, which themselves are undamped, collectively act so as to form a single damped mode identical to the usual Landau damped mode appropriate to zero magnetic field. The behavior of the plasma for small but finite magnetic field is also considered. It is shown that damping due to phase mixing exists for a time short compared to ωc−1, the reciprocal of the cyclotron frequency. In times long compared to this, the plasma exhibits a quasi-periodic behavior with period 2π/ωc.
Taylor Instability in a Viscous Liquid
Authors: Miles John W. , Dienes John K.
Published: December 2004

The effects of viscosity and surface tension on the Taylor instability of a plane slab of liquid are calculated approximately. The resulting approximation to the maximum growth rate is compared with the exact result in the limiting case of a semi-infinite liquid.
Natural Convection in Horizontal Liquid Layers
Authors: Catton Ivan
Published: December 2004

Natural convection in horizontal layers is examined. The eigenvalue problem yielding the characteristic Rayleigh numbers for the first ten modes is solved using linear theory. The contribution to heat transfer is determined and compared with experiment.
Sphere Drag at High Knudsen Number and Low Mach Number
Authors: Willis D. Roger
Published: December 2004

Knudsen iteration is used to calculate sphere drag at low Mach and high Knudsen numbers, using the Bhatnager, Gross, Krook model to describe the intermolecular collisions. Comparisons are made with previous approximate calculations and with experiment.
Hydromagnetic Free Jet
Authors: Wilson D. H.
Published: December 2004

A two-dimensional jet of conducting fluid issuing from a slot in a wall and acted on by a transverse magnetic field is found to be split into two jets parallel to the wall.
Possibility of Excitation of the Kelvin-Helmholtz Instability in Rotating Plasmas
Authors: O/ster Flemming
Published: December 2004

A discussion of the possibility of excitation of the Kelvin-Helmholtz instability in a rotating plasma is given. It is found that this type of instability does not seem to occur. The effect of viscosity is not taken into account.
Experimental Investigation of Single Interaction Nonadiabatic Losses from Axisymmetric Magnetic Mirrors
Authors: Roth J. Reece
Published: December 2004

The magnetic field strength, mirror ratio, and particle energy responsible for the onset of single interaction nonadiabatic losses were found to be correlated by a power-law similarity relation, if they are expressed in terms of certain dimensionless parameters.
Spatial Instability of the Inviscid Jet and Wake
Authors: Betchov R. , Criminale W. O.
Published: December 2004

The stability of the plane inviscid jet and wake is investigated for possible growth in the downstream spatial direction. The combined stability problem in space and time is also explored and numerical results are presented for growth factors and phase velocities.
Generation of the Third-Harmonic Current Density in a Plasma
Authors: Tang Ting-wei
Published: December 2004

An explicit expression for the third-harmonic current density generated by an alternating electric field is obtained for a velocity-dependent collision frequency by using a perturbation-theoretic approach.
Velocity Gradient Instability
Authors: Grad Harold
Published: December 2004

A recently formulated variational definition of stability for a guiding center plasma confined by mirrors was found to yield as a necessary condition for stability that the equilibrium distribution function f0(ε,μ,α,β) be monotone in energy on each magnetic line, ∂f0/∂ε ≤ 0. We now show, conversely, that if ∂f0/∂ε has too large a negative value, the plasma is always unstable. A quantitative formulation of this condition yields two inequalities that are necessary for stability of an arbitrary contained plasma. The same inequalities are sufficient for stability against all localized disturbances. Thus any remaining instabilities can only involve large scale disturbances of the plasma (e.g., interchanges). The localized (small wavelength) instabilities are found to be micro-instabilities even though the latter are usually thought to be missing in a theory with zero gyro radius and zero Debye radius. These micro-stability criteria are related to conditions for the stability of an infinite homogeneous plasma, and they serve to correct and generalize certain estimates of the maximum pressure that can be stably contained in a magnetic well.
Excitation of the m = 2 Mode by the Helical Instability
Authors: Holter O/ivin , Johnson Roy R.
Published: December 2004

The conditions whereby the helical instability can excite higher modes in the plasma column are investigated. The wavelengths and frequencies of the helical and m = 2 modes are calculated at the onset of the m = 2 mode for the case of helium.
Convective Instabilities in Plane Couette Flow
Authors: Ingersoll Andrew P.
Published: December 2004

The stability to infinitesimal disturbances of plane Couette flow is considered in the presence of a negative vertical temperature gradient. The fluid is contained between horizontal planes which are maintained at different temperatures. The flow becomes unstable at the critical Rayleigh number for convection without shear. Below this critical Rayleigh number, the flow is stable in the limit of large and small Reynolds numbers. Numerical solutions at finite Reynolds numbers are given for stationary and traveling disturbances at Prandtl numbers equal to ten and infinity. For these cases, the flow appears stable at subcritical Rayleigh numbers, for all Reynolds numbers.
Experimentally Determined Plasma Perturbation by a Probe
Authors: Little Roger G. , Waymouth John F.
Published: December 2004

The perturbation of a plasma by a probe with radius large in comparison to a mean free path is examined with a small movable probe. Electron density, electron temperature, and plasma potential are determined as a function of distance from the large probe. The experimental conditions corresponded well to those assumed by Waymouth; Waymouth's theory applied to the large-probe electron current characteristic yields a value for electron density in the unperturbed plasma that is correct within a few percent. The electron temperature so determined is too low by 19%. A fundamental assumption of all theories, that electron temperature in the perturbed volume of plasma is independent of position, is found to be incorrect, at least in a plasma containing drift currents.
Coupling of Transverse and Longitudinal Waves at the Upper Hybrid Frequency
Authors: Horton C. W.
Published: December 2004

Propagation of an electromagnetic wave into an increasingly dense plasma perpendicularly to a constant magnetic field is considered. The reflection coefficient is calculated in the limit of small electron Larmor radius and high frequency.
Injection and Trapping of Plasma Vortex Structures
Authors: Wells Daniel R.
Published: December 2004

Injection of a high density plasma into a magnetic mirror has been accomplished by generating plasma vortex structures under both mirror coils. Observations indicated that the structures move toward the center of the mirror and collide. Trapped magnetic fields in the structures produced a field reversal at the center of the mirror. The collision was followed by an oscillating motion of the ring currents flowing in the highly ionized plasma. Plasma was trapped inside the mirror for times of the order of milliseconds. There was no recycling of the gas in the mirror system. The plasma thermalized and then left through the escape cones and by diffusion to the walls. The ion temperature was of the order of 200 eV. Plasma volume was approximately 1000 cm3. Confining field was 10 kG.
Numerical Study of Large-Amplitude Free-Surface Motions
Authors: Harlow Francis H. , Welch J. Eddie
Published: December 2004

The marker and cell method for high-speed computer was used to investigate the motion of a fluid whose free surface has been perturbed by an impulsive sinusoidal pressure. For gravity pointing out of the fluid, the resulting motion exhibits Rayleigh-Taylor instability, whose progress is followed from low amplitude to the asymptotic bubble and spike stage. The effects of small and large viscosity are contrasted. For gravity pointing into the fluid, the large-amplitude oscillatory motion exhibits a shift of resonance frequency and other effects of nonlinearity. Comparisons of results are presented wherever previous analytical or experimental work was available, and many new aspects of these types of flow are discussed. The calculations are based upon the full, time-dependent, nonlinear Navier-Stokes equations for an incompressible fluid.
Solutions of Euler's Equations containing Finite Eddies
Authors: Childress Stephen
Published: December 2004

Stationary, two-dimensional solutions of Euler's equations which contain closed regions of constant vorticity are studied. Formal approximations valid when the eddy is slender are used to reduce the interaction problem to a nonlinear integral equation. Solutions of the integral equation which represent (i) wake bubbles reducing to Riabouchinsky's model for zero vorticity and (ii) finite, cusped wakes attached to a slender wedge are derived. The branch structure of single-eddy solutions is discussed.
Density Variation due to Reflected Shock-Boundary-Layer Interaction
Authors: Dyner Harry B.
Published: December 2004

The interaction of the reflected shock with the incident shock boundary layer has been investigated using strip-film schlieren interferometry. The effect of boundary-layer separation was observed to disappear within 50 μsec after passage of the reflected shock; thus the late density behavior is governed solely by the flow properties ahead of the reflected shock and by the chemical properties of the gas. Marked reflected shock decelerations near the back wall were observed only when endothermic reactions occurred behind the reflected shock, with subsequent acceleration due to the increasing strength of boundary-layer separation and shock bifurcation. Reflected shock density varied according to [Δρ/ρ5(0)] = ktN (0.4 ≤ N ≤ 0.9), after boundary-layer-separation effects had disappeared and before the effect of transition occurring in the boundary layer ahead of the reflected shock was felt. Relative bifurcated foot velocities increased with increasing Mach number and decreasing specific heat ratio. The mechanism causing the growth of the foot is discussed.
Flow Calculations for Pulsating One-Dimensional Detonations
Authors: Fickett W. , Wood W. W.
Published: December 2004

The nature of the long-time flow in an idealized one-dimensional, piston-supported detonation is investigated by numerical solution of the time-dependent hydrodynamic equations. The method of characteristics is used, with shocks treated as jump discontinuities. The fluid is an ideal gas of constant heat capacity undergoing an exothermic, irreversible, unimolecular reaction A → B obeying an Arrhenius rate law. The results are consistent with Erpenbeck's linearized analysis of the stability of the steady detonation, which revealed some cases in which the usual steady-state solution is unstable to infinitesimal longitudinal perturbations. In a typical flow of this type, the shock pressure is found to oscillate about the steady-solution value with a peak pressure nearly 50% higher and with a period of about 9 steady-solution half-reaction times.
High-Frequency ``Loss-Cone'' Flute Instabilities Inherent to Two-Component Plasmas
Authors: Pearlstein L. D. , Rosenbluth M. N. , Chang D. B.
Published: December 2004

When a low-temperature homogeneous plasma is added to a high-temperature ``loss-cone'' limited homogeneous plasma in the presence of a uniform magnetic field, high-frequency ``flute''-type unstable oscillations occur. For a fractional density of hot plasma (Δ) on the order of unity, the frequency and growth rates are on the order of the ion (electron) cyclotron harmonic frequency, where the harmonic number (N) is determined by the ratio of plasma to cyclotron frequency for ions (electrons). If ΔN ∼ 1 the instability occurs at the lower (upper) hybrid frequency. For ΔN ≪ 1 the instability only occurs when the ion (electron) cyclotron harmonic is equal to the lower (upper) hybrid frequency.
Fluctuation Scattering and Absorption Cross Section in a Space Dispersive Plasma
Authors: Macrakis Michael S.
Published: December 2004

The fluctuation scattering and absorption cross section have been derived for a space and time dispersive plasma. Fluctuations are introduced in Maxwell's equation describing a space-time dispersive plasma by considering the Boltzmann-Vlasov equations with an external field, and the cross sections are derived by evaluating the imaginary part of the correction to the transverse dielectric coefficient due to fluctuation scattering. The scattering cross section describes the total incoherent scattering from density fluctuations in the plasma while the absorption cross section describes the parametric interaction of an external propagating field with the internal excitations of the plasma. It is shown that when a collisionless plasma is pumped at twice the plasma frequency, the absorption cross section becomes very large. This suggests the possibility of increasing the energy content of the electron fluctuations near the plasma frequency. The pump acts to decrease the interaction between the free electrons and the collective plasma mode, a mechanism considered to account of Landau damping.
Hamilton's Principle for Fluids
Authors: Penfield Paul
Published: December 2004

Hamilton's principle is used to derive the force equation for both nonrelativistic and relativistic flow of a compressible, one-species, inviscid fluid. Rotational flow is predicted by use of Lin's constraint. Lin's constraint is given a physical interpretation and found to be considerably simplified by use of four-dimensional notation.
Two-Parameter Intermolecular Potential Energy Functions for Simple Molecules
Authors: Dymond J. H. , Rigby M. , Smith E. B.
Published: December 2004

The applicability to the properties of simple gases and solids of Lennard-Jones n–6 potentials having n equal to 16, 18, and 20 has been investigated. Values of the second virial coefficients for the 16–6 and 20–6 potentials are reported, together with the third virial coefficients and collision integrals for the 16–6 and 18–6 potentials. Comparisons are made with the experimental data for the inert gases, and it is concluded that either the 16–6 or 18–6 potential is able to describe the gas phase properties as well as the Kihara model, while retaining the greater convenience associated with a two-parameter potential.
Diffusion of Species over Surfaces with Discontinuous Catalycity
Authors: Simpkins P. G.
Published: December 2004

Solutions to the diffusion equation are presented when subjected to a discontinuous catalytic-surface boundary condition for a chemically frozen partially dissociated gas. The method utilized is the Mellin-transform calculus which makes the diffusion equation more amenable to analytic solutions. Two cases are considered, a step change in catalycity and the problem of a narrow catalytic gauge situated on a noncatalytic wall. In both cases expressions are derived for the heat-transfer contributions due to atomic recombination, in terms of the Nusselt number.
Plasma Waves at Singular Turning Points
Authors: Gorman D.
Published: December 2004

Connection formulas at a singular turning point are presented for the WKB solutions to a biquadratic differential equation governing wave propagation in an inhomogeneous plasma.
Correlation Formulas for Laminar Shock Tube Boundary Layer
Authors: Mirels H.
Published: December 2004

The laminar boundary layer behind a moving shock is studied. The major objective is to obtain improved correlation formulas (valid for large W, where W is the density ratio across the shock) and to simplify the procedure for obtaining boundary-layer parameters. Numerical solutions for shear, heat transfer, and boundary-layer thicknesses are presented for 1 ≤ W ≤ ∞, σ = 0.67, 0.72, and 1.0 (σ is the Prandtl number) assuming constant ρμ (ρ is the density and μ, the viscosity) and an ideal gas. Correlation formulas are obtained which agree with these numerical results to within fractions of a percent. Approximate corrections for variable ρμ and real-gas effects are then introduced. Charts and tables are presented which describe boundary layers in air (Ms ≤ 22) and argon (Ms ≤ 10).
Approach to Equilibrium in a Moderately Dense Discrete Velocity Gas
Authors: Harris S.
Published: December 2004

A discrete velocity model is used to study the approach to equilibrium in a gas in which both binary and ternary collisions occur. It is found that an H-theorem can be shown for the three-particle collision term and that the equilibrium distribution is the analog for the model of the Maxwell-Boltzmann distribution.
Low-Temperature Quantum Corrections to the Second Virial Coefficient
Authors: Michels H. H.
Published: December 2004

The first and second quantum corrections to the second virial coefficient have been evaluated in closed form for a (6–12) potential. Such corrections are useful for studying the low-temperature behavior of a gas and for calculating the thermodynamic properties of diatomic gases at high temperatures where the system can be treated as a chemically reacting assembly of atoms with strong interactions. Calculated values of these quantum corrections and their first and second temperature derivatives are given.
Parametric Excitation of Transverse Waves in a Plasma
Authors: Montgomery David , Alexeff Igor
Published: December 2004

It is shown that an externally-imposed, oscillating electric field excites transverse electromagnetic waves propagating perpendicularly to it, in a cold plasma. The mechanism is closely related to the parametric excitation of longitudinal plasma oscillations recently predicted by Aliev and Silin. The problem provides an application of nonsecular perturbation methods, when the equations of motion are expanded in powers of the external electric field. Arbitrarily small perturbations which arise spontaneously in the plasma are amplified by the action of the electric field, for a certain range of the driving frequency. The growth rate of the oscillations is calculated.
First Correction to the Second Adiabatic Invariant of Charged-Particle Motion
Authors: Northrop T. G. , Liu C. S. , Kruskal M. D.
Published: December 2004

The second term has been obtained in the asymptotic series for the second (longitudinal) adiabatic invariant of charged-particle motion in a static magnetic field. This correction to the lowest-order invariant has two sources: the correction to the lowest-order magnetic moment and the integrated effect of the guiding-center drift across the field lines. The second term is found to vanish at the mirror points; therefore, during its motion between mirror reflections, the guiding center deviates from the surface on which the lowest-order invariant is constant and intersects this surface at reflection.
Electrostatic Probe in a Collisionless Plasma
Authors: Kiel R. E. , Gustafson W. A.
Published: December 2004

The theory developed differs from classical Langmuir theory in that the potential at the sheath's edge need not be the ambient potential and the velocity distribution function for each species is determined for all points in space, rather than at the probe surface only. The range of validity of the classical theory is discussed quantitatively by presentation of several solutions for the spatial distributions of potential. Examination of an earlier result given for a moderately negative probe and mono-energetic ions reveals an inconsistent formulation; an exact result is presented. A solution for the infinite collisionless field of arbitrary potential distribution is derived, and an approximate form of this solution is compared with numerical results.
Structure of the Vibrational Relaxation Zone of Shock Waves in Oxygen
Authors: Lutz Robert W. , Kiefer John H.
Published: December 2004

The vibrational relaxation zone of incident shock waves in oxygen has been observed with the laser schlieren technique. Thirty experiments were examined covering the temperature range 1000–3700°K. The experimental observations were subjected to an accurate numerical analysis based on the energy relaxation equation [dEν/dt=(Eνeq−Eν)/τ], and the temperature dependence of τ derived from individual experiments was compared with the temperature dependence derived from the entire set. The two temperature trends are found to agree, showing the adequacy of the energy equation as a description of relaxation in oxygen. The variation of the relaxation time with temperature is given by Pτ = (2.92 ± 0.20) × 10−10 exp [(126.0 ± 0.9)/T⅓] atm sec, which is in general agreement with previous data. Possible reasons for the apparent failure of the energy equation in the CO2 relaxation experiments of Johannesen et al. are discussed. A simple modification of the Blackman procedure for the analysis of relaxation data is suggested. This modification is shown to reduce the discrepancy between exact and approximate values of τ by a factor of three for O2 relaxation at temperatures greater than 1200°K.
Couple Stresses in Fluids
Authors: Stokes Vijay Kumar
Published: December 2004

The effects of couple stresses in fluids are considered. Linearized constitutive equations are proposed for force and couple stresses. A series of boundary-value problems are solved to indicate the effects of couple stresses as well as for experiments measuring the various material constants. It is found that a size effect comes in which is not present in the nonpolar case (couple stresses absent).
Poloidal Hydromagnetic Plasmaspheric Resonances
Authors: Carovillano R. L. , Radoski H. R. , McClay J. F.
Published: December 2004

Under conditions of axisymmetry, the vector hydromagnetic wave equation of an infinitely conducting, stationary plasma permeated by a magnetic dipole field decouples into independent toroidal and poloidal modes. A general treatment is provided of the poloidal mode for a wide variety of radial and latitude-dependent plasma densities. A harmonic decomposition of the poloidal wave equation is made, resulting in radial equations which are coupled except for the special case where the Alfvén speed is latitude independent. Exact solutions are obtained in the latter case, and these are used to provide a general solution to the coupled equations for the general case. The method is applied to a model plasma confined between spherical surfaces concentric with the dipole. Resonance periods are calculated for the separable case with various positions of the outer plasma boundary. Periods are also obtained for a spherically symmetric density, and an evaluation of earlier approximate studies of this case is made.
Attenuation in Shock Tubes
Authors: Slepička F.
Published: December 2004

Simple theoretical derivation is given of the empirical formula of Emrich and Wheeler which enables one to calculate the shock wave attenuation due to boundary layer effect from the initial pressure conditions in a shock tube.
RHAMM, a receptor for hyaluronan-mediated motility, compensates for CD44 in inflamed CD44-knockout mice: A different interpretation of redundancy
Authors: Nedvetzki Shlomo , Gonen Erez , Assayag Nathalie , Reich Reuven , Williams Richard O. , Thurmond Robin L. , Huang Jing-Feng , Neudecker Birgit A. , Wang Fu-Shang , Turley Eva A. , Naor David
Published: December 2004

We report here that joint inflammation in collagen-induced arthritis is more aggravated in CD44-knockout mice than in WT mice, and we provide evidence for molecular redundancy as a causal factor. Furthermore, we show that under the inflammatory cascade, RHAMM (receptor for hyaluronan-mediated motility), a hyaluronan receptor distinct from CD44, compensates for the loss of CD44 in binding hyaluronic acid, supporting cell migration, up-regulating genes involved with inflammation (as assessed by microarrays containing 13,000 cDNA clones), and exacerbating collagen-induced arthritis. Interestingly, we further found that the compensation for loss of the CD44 gene does not occur because of enhanced expression of the redundant gene (RHAMM), but rather because the loss of CD44 allows increased accumulation of the hyaluronic acid substrate, with which both CD44 and RHAMM engage, thus enabling augmented signaling through RHAMM. This model enlightens several aspects of molecular redundancy, which is widely discussed in many scientific circles, but the processes are still ill defined.
Golgi inheritance in small buds of
Saccharomyces cerevisiae
is linked to endoplasmic reticulum inheritance
Authors: Reinke Catherine A. , Kozik Patrycja , Glick Benjamin S.
Published: December 2004

According to the cisternal maturation hypothesis, endoplasmic reticulum (ER)-derived membranes nucleate new Golgi cisternae. The yeast
Saccharomyces cerevisiae
offers a unique opportunity to test this idea because small buds contain both ER and Golgi structures early in the cell cycle. We previously predicted that mutants defective in ER inheritance also would show defects in Golgi inheritance. Surprisingly, studies of
S. cerevisiae
have not revealed the expected link between ER and Golgi inheritance. Here, we revisit this issue by generating mutant strains in which many of the small buds are devoid of detectable ER. These strains also show defects in the inheritance of both early and late Golgi cisternae. Strikingly, virtually all of the buds that lack ER also lack early Golgi cisternae. Our results fit with the idea that membranes exported from the ER coalesce with vesicles derived from existing Golgi compartments to generate new Golgi cisternae. This basic mechanism of Golgi inheritance may be conserved from yeast to vertebrate cells.
A Novel System to Diagnose Cutaneous Adverse Drug Reactions Employing the Cellscan—Comparison with Histamine Releasing Test and Inf‐γ Releasing Test
Authors: Goldberg Ilan , Gilburd Boris , Kravitz Martine Szyper , Kivity Shmuel , Ben Chaim Berta , Klein Tirza , Schiffenbauer Yael , Trubniykovr Ela , Brenner Sarah , Shoenfeld Yehuda
Published: December 2004

Background: There are several mechanisms to describe allergic drug
reactions yet the methods to diagnose them are limited.

Objective: To compare several conventional clinical and laboratory
methods to diagnose skin reactions to drugs
to a new method of diagnosing drug reactions by the CellScan system.

Methods: The study entailed 21 patients who were diagnosed as
suffering from drug eruptions, and 105 healthy controls with no history of drug
allergy. The drugs were classified into two groups according to suspicion of
causing drug allergy: high and low. Most of the patients were on more than
one drug, leading to 41 patient‐drug interactions (assays). Histamine
releasing test (HRT), interferon (INF)‐γ releasing test and CellScan
examination were performed on lymphocytes of the patients and controls.

Results: The HRT was interpreted as positive in 9 out of 18 (50%)
patients and in 13 out of 35 (37%) assays. Based on the INF‐γ releasing test,
positive results were observed in 16 out of 21 (76%) patients and in 24 out of 41
(59%) assays. In the CellScan test (CST), positive results were observed in 17
out of 21 (81%) patients and in 29 out of 41 (71%) assays. The rate of identifying
the drug for eruption in the high suspicion level drugs was 9 out of 22 (41%)
assays in the HRT, 20 out of 24 (83%) assays in the INF‐γ releasing test, and 21
out of 24 (87%) studies with the CellScan method. The rate of determining of
the drug that caused the eruption in the low suspicion level drugs was 4 out of
13 (31%) in the HRT, 4 out of 17 (24%) assays in the INF‐γ releasing test, and 8
out of 17 (47%) analyses in the CST. When examined
in the CellScan, 99 out of 105 (94%) controls were interpreted as negative.

Conclusion: This preliminary study indicates that the CellScan seems to
be an easy and promising method for the detection of drugs responsible for
adverse skin reactions. In contrast to the HRT and to the Interferon‐γ secretion
test, the CellScan method is characterized by its ability to track and monitor
the reaction of individual cells. By measuring the kinetic parameters of selected
cells before and after adding the suspected drug, we were able to identify
the culprit drug. The CellScan method had the highest sensitivity, and the
interferon‐γ secretion test had the highest specificity for detection of the culprit
drug. In contrast, the analysis of 105
normal control sera disclosed a high specificity of 94% for the CellScan method.
Impaired IFN‐γ Production by Viral Immunodominant Peptide‐specific Tetramer+ CD8+ T Cells in HIV‐1 Infected Patients is not Secondary to HAART
Authors: Onlamoon Nattawat , Pattanapanyasat Kovit , Ansari Aftab A.
Published: December 2004

Studies on PBMC samples from HIV‐1 infected patients have shown that despite
substantial number of HIV specific CTLs, these patients gradually progress to AIDS.
The present study was conducted to determine whether this paradox was secondary
to the influence of protease inhibitors being utilized by these patients. Thus, aliquots
of PBMC samples from 10 HIV infected humans with no prior history of anti‐retroviral
drug therapy (ART) and 6 HIV‐infected patients that had been on HAART for >1 year
were analyzed for the frequency of HIV‐1 Nef and Gag dominant peptide specific
tetramer+ cells, respectively. The tetramer+ PBMCs were analyzed for their ability
to synthesize specific peptide induced IFN‐γ utilizing both the ELISPOT and the
intracellular cytokine (ICC) assays. Results of the studies showed that there was
an overall correlation between the frequency of Nef and Gag peptide tetramer+
cells and the frequency of IFN‐γ synthesizing cells as assayed by either ICC or
ELISPOT assay, markedly reduced values of IFN‐γ synthesizing cells per unit
tetramer+ cells were noted in both group of patients. These data suggest that
the frequency of HIV‐specific CD8+T cells is maintained during the chronic phase
of infection, their ability to function is compromised and is not a reflection of ART.
While the addition of IL‐2, anti‐CD40L and allogeneic cells led to partial increase
in the ability of the tetramer+ cells to synthesize IFN‐γ, the addition of IL‐4, IL‐12,
anti‐CD28 or a cocktail of anti‐TGF‐β, TNF‐α and IL‐10 failed to augment the IFN‐γ response.
The Effects of Enterococcus faecium and Selenium on Methotrexate Treatment in Rat Adjuvant‐induced Arthritis
Authors: Rovenský Jozef , šv­k Karol , Mat′ha Vladim­r , Itok Richard , Ebringer Ladislav , Ferenčík Miroslav , StanĨ­ková Mária
Published: December 2004

The effects of probiotic bacteria Enterococcus faecium (EF)
and selenium were studied on methotrexate (MTX) treatment in rats with adjuvant
arthritis (AA).

Arthritic rats were preventive treated orally with the following substances:
lyophilized EF (15 mg/kg/day, 5 days a week); sodium selenite pentahydrate
(SSe, 0.050 mg/kg containing 0.015 mg/kg selenium, 5 days a week); MTX (0.6
mg/kg/week), and their combinations for the period of 50 days from adjuvant
application. Levels of serum albumin, serum nitrite/nitrate concentrations, hind
paw swelling, arthrogram scores, whole body bone mineral density (BMD), and
bone erosions were evaluated
as markers of inflammation and destructive changes associated with arthritis.

Long‐term preventive treatment with low‐dose MTX significantly inhibited
the markers of both inflammation and arthritis. EF or SSe when administered
singly or in combination had no significant effect on given parameters in arthritic
rats. EF but not SSe potentiated the beneficial effects of MTX, which resulted in
a more significant reduction of hind paw swelling, arthrogram scores and whole
body BMD decrease. EF had a tendency to improve also the effect of MTX on
serum albumin and nitrite/nitrate concentrations.

Our results indicate that EF may increase the preventive effect of MTX
treatment in
rat AA by improving its anti‐inflammatory and anti‐arthritic effects.
Britain's Invisible Dividends
Authors: Clohesy Anthony M.
Published: December 2004

This article argues that the left is generally right in its claim that Britain is important and should be valued. However, it fails to consider two important arguments. The first is theoretical and draws broadly on discourse theory. It argues that Britain's value lies in the fact that it is an artificial and contingent entity. It is this that allows it to accommodate such a broad range of ethnicities and identities. This is related to my second argument. This proposes that the benefits of English regional authorities – citizenship, democratisation and greater economic prosperity – can only be realised fully in the context of a unified British state committed to the principles of inclusion and tolerance.
The Ladder of Abstraction: A Framework for the Systematic Classification of Democratic Regime Types
Authors: Daly Siobhan
Published: December 2004

This article argues that classificatory problems such as parochialism, misclassification, degreeism and conceptual stretching underpin the classification of democratic regime types. This is due to the safeguarding of the parliamentary/presidential dichotomy as a framework for the classification and comparison of democratic types of regime. Drawing upon Giovanni Sartori's ladder of abstraction, types of democratic regime are classified as part of a hierarchy of concepts. This approach enables scholars to avoid classificatory pitfalls as it facilitates the methodological expansion of the conceptual framework for the classification of democratic regime types. Therefore, democratic regime types are more conducive to systematic comparative research.
The Preparation of the Governance White Paper
Authors: Sloat Amanda
Published: December 2004

The European Commission's White Paper on Governance initiated a Europe-wide debate about the principles and practices of good policymaking. This article, which draws from the author's work with the team that prepared the White Paper, provides a first-hand examination of how the document was produced. Following a discussion about the meaning of governance, the article focuses on the timeline of events, the consultation procedures, and some of the challenges (linguistic, practical, and political) that arose. It concludes by placing the governance debate in the context of the ongoing European Convention and 2004 IGC.
Democracy and Political Scepticism: Comment on Bufacchi
Authors: Hyland James (Eddie)
Published: December 2004

The claim that democracy requires a particular type of political scepticism for its justification has an initial plausibility. The present article argues, however, that Bufacchi does not succeed in adequately identifying the relevant type of uncertainty. Secondly, it is claimed here that Bufacchi's analysis neglects a crucial element in the justification of democracy, namely, the positive evaluation of moral autonomy. When the role of autonomy is given its proper place epistemology becomes secondary, providing a basis not for scepticism but for a theory such as Rawls's theory of reasonable disagreement.
Effects of Fear and Anger on Perceived Risks of Terrorism
Authors: Lerner Jennifer S. , Gonzalez Roxana M. , Small Deborah A. , Fischhoff Baruch
Published: December 2004

The aftermath of September 11th highlights the need to understand how emotion affects citizens' responses to risk. It also provides an opportunity to test current theories of such effects. On the basis of appraisal-tendency theory, we predicted opposite effects for anger and fear on risk judgments and policy preferences. In a nationally representative sample of Americans (N = 973, ages 13–88), fear increased risk estimates and plans for precautionary measures; anger did the opposite. These patterns emerged with both experimentally induced emotions and naturally occurring ones. Males had less pessimistic risk estimates than did females, emotion differences explaining 60 to 80% of the gender difference. Emotions also predicted diverging public policy preferences. Discussion focuses on theoretical, methodological, and policy implications.
Effects of Experience on Fetal Voice Recognition
Authors: Kisilevsky Barbara S. , Hains Sylvia M.J. , Lee Kang , Xie Xing , Huang Hefeng , Ye Hai Hui , Zhang Ke , Wang Zengping
Published: December 2004

The ability of human fetuses to recognize their own mother's voice was examined. Sixty term fetuses were assigned to one of two conditions during which they were exposed to a tape recording of their mother or a female stranger reading a passage. Voice stimuli were delivered through a loudspeaker held approximately 10 cm above the maternal abdomen and played at an average of 95 dB SPL. Each condition consisted of three 2-min periods: no stimulus, voice (mother or stranger), and no stimulus. Fetal heart rate increased in response to the mother's voice and decreased in response to the stranger's; both responses were sustained for 4 min. The finding of differential behavior in response to a familiar versus a novel voice provides evidence that experience influences fetal voice processing. It supports an epigenetic model of speech perception, presuming an interaction between genetic expression of neural development and species-specific experience.
The Development of Numerical Estimation
Authors: Siegler Robert S. , Opfer John E.
Published: December 2004

We examined children's and adults' numerical estimation and the representations that gave rise to their estimates. The results were inconsistent with two prominent models of numerical representation: the logarithmic-ruler model, which proposes that people of all ages possess a single, logarithmically spaced representation of numbers, and the accumulator model, which proposes that people of all ages represent numbers as linearly increasing magnitudes with scalar variability. Instead, the data indicated that individual children possess multiple numerical representations; that with increasing age and numerical experience, they rely on appropriate representations increasingly often; and that the numerical context influences their choice of representation. The results, obtained with second graders, fourth graders, sixth graders, and adults who performed two estimation tasks in two numerical contexts, strongly suggest that one cause of children's difficulties with estimation is reliance on logarithmic representations of numerical magnitudes in situations in which accurate estimation requires reliance on linear representations.
Speech Shadowing While Driving
Authors: Spence Charles , Read Liliana
Published: December 2004

We investigated the role of cross-modal links in spatial attention in modulating the efficiency of dual-task performance. The difficulty of combining speech shadowing with a simulated driving task was modulated by the spatial location from which the speech was presented. In both single- and dual-task conditions, participants found it significantly easier to shadow one of two auditory streams when the relevant speech was presented from directly in front of them, rather than from the side. This frontal speech advantage was more pronounced when participants performed the demanding simulated driving task at the same time as shadowing than when they performed the shadowing task alone. These results demonstrate that people process auditory information more efficiently (with a lower overall dual-task decrement) when relevant auditory and visual stimuli are presented from the same, rather than different, spatial locations. These results are related to recent findings showing that there are extensive cross-modal links in spatial attention, and have clear implications for the design of better user interfaces.
Privatization morphs into ‘publicization’: businesses look a lot like government
Authors: Sellers Martin P.
Published: December 2004

Private companies become like public agencies because competition for contracts is keen and they must be perceived by the contacting agent, government, as being agreeable with the government's demands in order to be contracted with again. Government makes suggestions, sets requirements, and provides recommendations to private companies which, over time, cause the private companies/facilities to look more and more like government agencies – and company managers are left pressed between their need to re‐contract and the business instincts and acumen for which they’ve presumably been contracted with in the first place.

This paper will briefly visit the common arguments for and against privatization. Additionally, the results of a limited study of the effect of publicization on private prison companies operating nationally in the US will be examined.
Distributions Generated by Perturbation of Symmetry with Emphasis on a Multivariate Skewt-Distribution
Authors: Azzalini Adelchi , Capitanio Antonella
Published: December 2004

A fairly general procedure is studied to perturb a multivariate density satisfying a weak form of multivariate symmetry, and to generate a whole set of non-symmetric densities. The approach is sufficiently general to encompass some recent proposals in the literature, variously related to the skew normal distribution. The special case of skew elliptical densities is examined in detail, establishing connections with existing similar work. The final part of the paper specializes further to a form of multivariate skew t-density. Likelihood inference for this distribution is examined, and it is illustrated with numerical examples.
Functional Quasi-Likelihood Regression Models with Smooth Random Effects
Authors: Chiou Jeng-Min , Müller Hans-Georg , Wang Jane-Ling
Published: December 2004

We propose a class of semiparametric functional regression models to describe the influence of vector-valued covariates on a sample of response curves. Each observed curve is viewed as the realization of a random process, composed of an overall mean function and random components. The finite dimensional covariates influence the random components of the eigenfunction expansion through single-index models that include unknown smooth link and variance functions. The parametric components of the single-index models are estimated via quasi-score estimating equations with link and variance functions being estimated nonparametrically. We obtain several basic asymptotic results. The functional regression models proposed are illustrated with the analysis of a data set consisting of egg laying curves for 1000 female Mediterranean fruit-flies (medflies).