Do the precise measurements of the Casimir force agree with the expectations?

An upper limit on the Casimir force is found using the dielectric functions of perfect crystalline materials which depend only on well defined material constants. The force measured with the atomic force microscope is larger than this limit at small separations between bodies and the discrepancy is significant. The simplest modification of the experiment is proposed allowing to make its results more reliable and answer the question if the discrepancy has any relation with the existence of a new force.Comment: 9 pages, LaTeX, 2 Postscript figure

On the Strength of Spin-Isospin Transitions in A=28 Nuclei

The relations between the strengths of spin-isospin transition operators extracted from direct nuclear reactions, magnetic scattering of electrons and processes of semi-leptonic weak interactions are discussed.Comment: LaTeX, 8 pages, 1Postscript with figur

A VLA Search for the Geminga Pulsar: A Bayesian Limit on a Scintillating Source

We derive an upper limit of 3 mJy (95% confidence) for the flux density at 317 MHz of the Geminga pulsar (J0633+1746). Our results are based on 7 hours of fast-sampled VLA data, which we averaged synchronously with the pulse period using a period model based on CGRO/EGRET gamma-ray data. Our limit accounts for the fact that this pulsar is most likely subject to interstellar scintillations on a timescale much shorter than our observing span. Our Bayesian method is quite general and can be applied to calculate the fluxes of other scintillated sources. We also present a Bayesian technique for calculating the flux in a pulsed signal of unknown width and phase. Comparing our upper limit of 3 mJy with the quoted flux density of Geminga at 102 MHz, we calculate a lower limit to its spectral index of 2.7. We discuss some possible reasons for Geminga's weakness at radio wavelengths, and the likelihood that many of the unidentified EGRET sources are also radio-quiet or radio-weak Geminga-like pulsars.Comment: 27 pages, including figures. Published in Ap

Toward An Empirical Theory of Pulsar Emission. VII. On the Spectral Behavior of Conal Beam Radii and Emission Heights

In this paper we return to the old problem of conal component-pair widths and profile dimensions. Observationally, we consider a set of 10 pulsars with prominent conal component pairs, for which well measured profiles exist over the largest frequency range now possible. Apart from some tendency to narrow at high frequency, the conal components exhibit almost constant widths. We use all three profile measures, the component separation as well as the outside half-power and 10% widths, to determine conal beam radii, which are the focus of our subsequent analysis. These radii at different frequencies are well fitted by a relationship introduced by Thorsett (1991), but the resulting parameters are highly correlated. Three different types of behavior are found: one group of stars exhibits a continuous variation of beam radius which can be extrapolated down to the stellar surface along the ``last open field lines''; a second group exhibits beam radii which asymptotically approach a minimum high frequency value that is 3--5 times larger; and a third set shows almost no spectral change in beam radius at all. The first two behaviors are associated with outer-cone component pairs; whereas the constant separation appears to reflect inner-cone emission.Comment: 21 pages, 11 figures, accepted for publication in Astrophysical Journal, uses aaste

The magnetocaloric effect in materials with a second order phase transition: Are T C and T peak necessarily coincident?

Using the Arrott–Noakes equation of state it is shown that the Curie point TC and the temperature where the magnetic entropy change is maximum Tpeak coincide only in the mean field approximation, but the Heisenberg model implies that Tpeak TC even for homogeneous materials. The distance between Tpeak and TC increases with applied magnetic field following a power law. In both cases, TC corresponds to a singular point in the temperature dependence of the magnetic entropy change. The field dependence of the magnetic entropy change is exactly the same at the Curie temperature and at the temperature of the peak

Electron Correlations in the Low Carrier Density LaFeAsO0.89F0.11 Superconductor (Tc = 28 K)

The crystal structure and numerous normal and superconducting state properties of layered tetragonal (P4/nmm) LaFeAsO, with F-doping of 11 %, are reported. Resistivity measurements give an onset transition temperature Tc = 28.2 K, and low field magnetic susceptibility data indicate bulk superconductivity. In applied magnetic field, analysis of the resistive transition results in a critical field Hc2 = 30 T and a coherence length 35 A. An upper limit for the electron carrier concentration of 1 x 10^21 cm-3 is inferred from Hall data just above Tc. Strong electron-electron correlations are suggested from temperature-dependent resistivity, Seebeck coefficient, and thermal conductivity data. Anomalies near Tc are observed in both Seebeck coefficient and thermal conductivity data.Comment: 13 pages, 8 figure

Перспективы использования концепции «шести сигм» в менеджменте качества судебно-экспертной деятельности: «за» и «против»

The article analyzes modern trends in the development of forensic activities. The author notes that under conditions of constant growth of the number of expert tasks and increase their complexity, we developed the objective prerequisites for the introduction in the forensic activities of the quality management system. Special attention is paid to analysis of the most modern concepts of quality management are “six sigma”, revealed its content, the author briefly describes the history and implementation of management practices foreign forensic laboratories. The possibilities of this approach to ensure comparability of results of monitoring various indicators of quality. The author notes that this method of management of the organization is an important mechanism in ensuring economical production, which is important for forensic organizations in the current economic conditions. The strengths and weaknesses of the application of this concept in forensic science, and proposes options for its integration with traditional methods of quality management.В статье анализируются современные тенденции развития судебно-экспертной деятельности. Автор отмечает, что в условиях постоянного роста количества экспертных заданий и возрастания уровня их сложности сложились объективные предпосылки для внедрения в судебно-экспертную деятельность систем менеджмента качества. Особое внимание уделено анализу наиболее современной концепции управления качеством «шесть сигм», раскрыто ее содержание, кратко рассмотрена история возникновения и внедрения в практику управления зарубежных судебно-экспертных лабораторий. Показаны возможности данного подхода в области обеспечения сопоставимости результатов мониторинга различных показателей качества. Автор обращает внимание, что данная методика управления организацией является важным механизмом в обеспечении экономичного производства, что имеет большое значение для судебно-экспертных организаций в современных экономических условиях. Показаны сильные и слабые стороны применения данной концепции в судебной экспертизе, а также предложены варианты ее комплексирования с традиционными методами управления качеством

Современные модели менеджмента качества в судебно-экспертной деятельности

The article contains analysis of modern approaches to quality management in the forensic science institutions, reviewed evolution of the view about quality as an object of management. Author considered a structure and a volume of notion of forensic science activity and mark out the elements of structure that form complex factor that affects the quality. Based on international and one’s country experience is given the historical retrospective of process of development and deployment of mechanisms of managements of quality in production and forensic science. The conceptual approaches to quality problems enshrined in the series ISO 9000 and ISO/IEC 17025 international standards, their similarities and distinction, and also applicability limits concerning activity of the forensic science institutions are analyzed. The special attention is paid to the analysis of problems arising in the design and implementation of quality management systems, identified their causes, and made recommendations for improving the effectiveness of management.В статье содержится анализ современных подходов к менеджменту качества в судебно-экспертных организациях, проанализирована эволюция представлений о качестве как объекте управления. Автором рассмотрена структура и объем понятия судебно-экспертной деятельности и выделяются те ее элементы, которые формируют комплекс влияющих на качество факторов. На основе международного и отечественного опыта дана историческая ретроспектива процесса разработки и внедрения механизмов управления качеством в производстве и судебной экспертизе. Проанализированы концептуальные подходы к проблемам качества, закрепленные в международных стандартах ИСО серии 9000 и ИСО/МЭК 17025, их сходства и различия, а также пределы применимости в отношении деятельности судебно-экспертных организаций. Особое внимание уделено анализу проблем, возникающих в процессе проектирования и внедрения систем управления качеством, выявлены их причины и даны рекомендации по повышению эффективности менеджмента

Electronic structure, magnetic and optical properties of intermetallic compounds R2Fe17 (R=Pr,Gd)

In this paper we report comprehensive experimental and theoretical investigation of magnetic and electronic properties of the intermetallic compounds Pr2Fe17 and Gd2Fe17. For the first time electronic structure of these two systems was probed by optical measurements in the spectral range of 0.22-15 micrometers. On top of that charge carriers parameters (plasma frequency and relaxation frequency) and optical conductivity s(w) were determined. Self-consistent spin-resolved bandstructure calculations within the conventional LSDA+U method were performed. Theoretical interpetation of the experimental s(w) dispersions indicates transitions between 3d and 4p states of Fe ions to be the biggest ones. Qualitatively the line shape of the theoretical optical conductivity coincides well with our experimental data. Calculated by LSDA+U method magnetic moments per formula unit are found to be in good agreement with observed experimental values of saturation magnetization.Comment: 16 pages, 5 figures, 1 tabl

A CLEAN-based Method for Deconvolving Interstellar Pulse Broadening from Radio Pulses

Multipath propagation in the interstellar medium distorts radio pulses, an effect predominant for distant pulsars observed at low frequencies. Typically, broadened pulses are analyzed to determine the amount of propagation-induced pulse broadening, but with little interest in determining the undistorted pulse shapes. In this paper we develop and apply a method that recovers both the intrinsic pulse shape and the pulse broadening function that describes the scattering of an impulse. The method resembles the CLEAN algorithm used in synthesis imaging applications, although we search for the best pulse broadening function, and perform a true deconvolution to recover intrinsic pulse structre. As figures of merit to optimize the deconvolution, we use the positivity and symmetry of the deconvolved result along with the mean square residual and the number of points below a given threshold. Our method makes no prior assumptions about the intrinsic pulse shape and can be used for a range of scattering functions for the interstellar medium. It can therefore be applied to a wider variety of measured pulse shapes and degrees of scattering than the previous approaches. We apply the technique to both simulated data and data from Arecibo observations.Comment: 9 pages, 6 figures, Accepted for publication in the Astrophysical Journa