210 research outputs found

    One-dimensional quasi-relativistic particle in the box

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    Two-term Weyl-type asymptotic law for the eigenvalues of one-dimensional quasi-relativistic Hamiltonian (-h^2 c^2 d^2/dx^2 + m^2 c^4)^(1/2) + V_well(x) (the Klein-Gordon square-root operator with electrostatic potential) with the infinite square well potential V_well(x) is given: the n-th eigenvalue is equal to (n pi/2 - pi/8) h c/a + O(1/n), where 2a is the width of the potential well. Simplicity of eigenvalues is proved. Some L^2 and L^infinity properties of eigenfunctions are also studied. Eigenvalues represent energies of a `massive particle in the box' quasi-relativistic model.Comment: 40 pages, 4 figures; minor correction

    FUZZY SUBOPTIMAL FEEDBACK CONTROLLER

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    The paper concerns the time-optimal control of objects described by a differential equation representing the second law of Newtonian mechanics and taking into account a discon- tinuous model of resistances to motion. Such a task has broad technical applications, especially in robotics. A fuzzy approach is used to design a suboptimal closed-loop con- trol structure, convenient in practice thanks to its many advantages, especially in respect to robustness

    Are book publications disappearing from scholarly communication in the social sciences and humanities?

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    In the social sciences and humanities book publishing takes a prominent role, both in terms of communicating with international peers and with a broader intelligentsia (Hicks, 2004; Verleysen & Engels, 2014). Empirical evidence regarding the evolution of the share of scholarly book publications in the total volume of scholarly publications in a given country is rare. In this study we intend to fill this gap with an analysis of the comprehensive coverage data on the share of peer reviewed book publications (book chapters, edited volumes and monographs) that are available from Flanders and Slovenia for the period 2004 to 2015. We supplement these data with data on peer reviewed book chapters and monographs from Norway for the period 2005-2015 as well as data on all types of peer reviewed book publishing for the period 2009 to 2014 for Poland and 2011 to 2015 for Finland

    Are book publications disappearing from scholarly communication in the social sciences and humanities?

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    © 2018, Tim C.E. Engels, Andreja Istenič Starčič, Emanuel Kulczycki, Janne Pölönen and Gunnar Sivertsen. Purpose: The purpose of this paper is to analyze the evolution in terms of shares of scholarly book publications in the social sciences and humanities (SSH) in five European countries, i.e. Flanders (Belgium), Finland, Norway, Poland and Slovenia. In addition to aggregate results for the whole of the social sciences and the humanities, the authors focus on two well-established fields, namely, economics & business and history. Design/methodology/approach: Comprehensive coverage databases of SSH scholarly output have been set up in Flanders (VABB-SHW), Finland (VIRTA), Norway (NSI), Poland (PBN) and Slovenia (COBISS). These systems allow to trace the shares of monographs and book chapters among the total volume of scholarly publications in each of these countries. Findings: As expected, the shares of scholarly monographs and book chapters in the humanities and in the social sciences differ considerably between fields of science and between the five countries studied. In economics & business and in history, the results show similar field-based variations as well as country variations. Most year-to-year and overall variation is rather limited. The data presented illustrate that book publishing is not disappearing from an SSH. Research limitations/implications: The results presented in this paper illustrate that the polish scholarly evaluation system has influenced scholarly publication patterns considerably, while in the other countries the variations are manifested only slightly. The authors conclude that generalizations like “performance-based research funding systems (PRFS) are bad for book publishing” are flawed. Research evaluation systems need to take book publishing fully into account because of the crucial epistemic and social roles it serves in an SSH. Originality/value: The authors present data on monographs and book chapters from five comprehensive coverage databases in Europe and analyze the data in view of the debates regarding the perceived detrimental effects of research evaluation systems on scholarly book publishing. The authors show that there is little reason to suspect a dramatic decline of scholarly book publishing in an SSH

    VIRGO sensitivity to binary coalescences and the Population III black hole binaries

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    We analyze the properties of VIRGO detector with the aim of studying its ability to search for coalescing black hole binaries. We focus on the remnants of the Population III stars, which currently should be massive black holes (1001000M\sim 100-1000 M_\odot), some of them bound in binary systems. The coalescence of such binaries due to emission of gravitational waves may be currently observable. We use a binary population synthesis to model the evolution of Population III binaries. We calculate the signal to noise ratios of gravitational waves emitted by the system in each of the coalescence phase: inspiral, merger and ringdown, and provide simple formulae for the signal to noise ratio as a function of masses of the binaries. We estimate the detection rates for the VIRGO interferometer and also compare them with the estimates for the current LIGO. We show that these expected rates are similar to, or larger than the expected rates from coalescences of Population I and II compact object binaries.Comment: sumbitted to A&

    Influence of timing on CSF tests value for Creutzfeldt-Jakob disease diagnosis

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    Background: The analysis of markers in the cerebrospinal fluid (CSF) is useful in the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). However, the time at which the study of these markers is most sensitive remains controversal. Objective: To assess the influence of time of sampling on the value of CSF tests in the diagnosis of sCJD. Method: In the framework of a multinational European study, we studied the results of 14-3-3, S100b, neurone specific enolase (NSE) and tau protein in 833 CSF samples from sCJD patients at different stages of disease and in 66 sequentially repeated lumbar punctures (LP). Results: 14-3-3 and tau protein tended to increase in sensitivity from onset (88%, 81%) to the advanced stage (91%, 90%). This was significant only in the methionine-valine (MV) heterozygous group of patients at codon 129. The absolute levels of S100b (p < 0.05), NSE and tau protein increased in the last stage of disease. High levels of tau protein, NSE and S100b were associated with shorter survival times (p < 0.01). Sixty-six sCJD patients underwent repeated LP. These sCJD patients were younger, had longer disease durations and were more frequently MV at codon 129 (p < 0.001) than the whole group. 14-3-3 sensitivity increased from 64% to 82% in the second LP (p = 0.025) and 88% sCJD patients had at least one positive result. Conclusions: Sensitivity and absolute levels of CJD markers increased with disease progression and were modulated by the codon 129 genotype. Early negative results should be inter-preted with caution, especially in young patients or those who are MV at codon 129

    Symmetric Jump Processes and their Heat Kernel Estimates

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    We survey the recent development of the DeGiorgi-Nash-Moser-Aronson type theory for a class of symmetric jump processes(or equivalently, a class of symmetric integro-differential operators). We focus on the sharp two-sided estimates for the transition density functions (or heat kernels) of the processes, a priori Holder estimate and parabolic Harnack inequalities for their parabolic functions. In contrast to the second order elliptic differential operator case, the methods to establish these properties for symmetric integro-differential operators are mainly probabilistic.Comment: To appear in Science in China Series A: Mathematic

    Kinetics of biodegradation of diethylketone by Arthrobacter viscosus

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    The performance of an Arthrobacter viscosus culture to remove diethylketone from aqueous solutions was evaluated. The effect of initial concentration of diethylketone on the growth of the bacteria was evaluated for the range of concentration between 0 and 4.8 g/l, aiming to evaluate a possible toxicological effect. The maximum specific growth rate achieved is 0.221 h-1 at 1.6 g/l of initial diethylketone concentration, suggesting that for higher concentrations an inhibitory effect on the growth occurs. The removal percentages obtained were approximately 88%, for all the initial concentrations tested. The kinetic parameters were estimated using four growth kinetic models for biodegradation of organic compounds available in the literature. The experimental data found is well fitted by the Haldane model (R2 = 1) as compared to Monod model (R2 = 0.99), Powell (R2 = 0.82) and Loung model (R2 = 0.95). The biodegradation of diethylketone using concentrated biomass was studied for an initial diethylketone concentration ranging from 0.8–3.9 g/l in a batch with recirculation mode of operation. The biodegradation rate found followed the pseudo-second order kinetics and the resulting kinetic parameters are reported. The removal percentages obtained were approximately 100%, for all the initial concentrations tested, suggesting that the increment on the biomass concentration allows better results in terms of removal of diethylketone. This study showed that these bacteria are very effective for the removal of diethylketone from aqueous solutions.The authors would like to gratefully acknowledge the financial support of this project by the Fundacao para a Ciencia e Tecnologia (FCT), Ministerio da Ciencia e Tecnologia, Portugal and Fundo Social Europeu (FSE). Cristina Quintelas thanks FCT for a Post-Doc grant
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