236 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

    Travelling Randomly on the Poincar\'e Half-Plane with a Pythagorean Compass

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    A random motion on the Poincar\'e half-plane is studied. A particle runs on the geodesic lines changing direction at Poisson-paced times. The hyperbolic distance is analyzed, also in the case where returns to the starting point are admitted. The main results concern the mean hyperbolic distance (and also the conditional mean distance) in all versions of the motion envisaged. Also an analogous motion on orthogonal circles of the sphere is examined and the evolution of the mean distance from the starting point is investigated

    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

    A new trans-Ionian spider species for the Italian fauna: Habrocestum graecum Dalmas, 1920 (Araneae, Salticidae)

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    The salticid spider Habrocestum graecum Dalmas, 1920, until now only known from Greece, is for the first time recorded in Italy. Observations on ecology and behavior are also reported and pictures of its habitus and genitalia are provided. Furthermore, the first DNA barcode sequence for H. graecum is produced and made publicly available. The species has been observed in Puglia, in South-Eastern Italy, and a trans-Ionian dispersal pattern is most likely the cause of its presence both in Greece and Southern Italy, as reported for other taxa with similar distribution in different animal groups

    How to identify peer-reviewed publications: Open-identity labels in scholarly book publishing

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    This work was supported by the Ministry of Science and Higher Education in Poland (https://www.gov.pl/nauka/) within the DIALOG Programme: the project title ‘Research into Excellence Patterns in Science and Art’. Tim Engels and Raf Guns thank the Flemish government for its funding of the Center for R&D Monitoring (ECOOM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.This article discusses the open-identity label, i.e., the practice of disclosing reviewers’ names in published scholarly books, a common practice in Central and Eastern European countries. This study’s objective is to verify whether the open-identity label is a type of peer-review label (like those used in Finland and Flanders, i.e., the Flemish part of Belgium), and as such, whether it can be used as a delineation criterion in various systems used to evaluate scholarly publications. We have conducted a two-phase sequential explanatory study. In the first phase, interviews with 20 of the 40 largest Polish publishers of scholarly books were conducted to investigate how Polish publishers control peer reviews and whether the open-identity label can be used to identify peer-reviewed books. In the other phase, two questionnaires were used to analyze perceptions of peer-review and open-identity labelling among authors (n = 600) and reviewers (n = 875) of books published by these 20 publishers. Integrated results allowed us to verify publishers’ claims concerning their peer-review practices. Our findings reveal that publishers actually control peer reviews by providing assessment criteria to reviewers and sending reviews to authors. Publishers rarely ask for permission to disclose reviewers’ names, but it is obvious to reviewers that this practice of disclosing names is part of peer reviewing. This study also shows that only the names of reviewers who accepted manuscripts for publication are disclosed. Thus, most importantly, our analysis shows that the open-identity label that Polish publishers use is a type of peer-review label like those used in Flanders and Finland, and as such, it can be used to identify peer-reviewed scholarly books

    Journal article publishing in the social sciences and humanities: a comparison of Web of Science coverage for five European countries

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    This study compares publication pattern dynamics in the social sciences and humanities in five European countries. Three are Central and Eastern European countries that share a similar cultural and political heritage (the Czech Republic, Slovakia, and Poland). The other two are Flanders (Belgium) and Norway, representing Western Europe and the Nordics, respectively. We analysed 449,409 publications from 2013-2016 and found that, despite persisting differences between the two groups of countries across all disciplines, publication patterns in the Central and Eastern European countries are becoming more similar to those in their Western and Nordic counterparts. Articles from the Central and Eastern European countries are increasingly published in journals indexed in Web of Science and also in journals with the highest citation impacts. There are, however, clear differences between social science and humanities disciplines, which need to be considered in research evaluation and science policy

    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

    Aflatoxin levels, plasma vitamins A and E concentrations, and their association with HIV and hepatitis B virus infections in Ghanaians: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Micronutrient deficiencies occur commonly in people infected with the human immunodeficiency virus. Since aflatoxin exposure also results in reduced levels of several micronutrients, HIV and aflatoxin may work synergistically to increase micronutrient deficiencies. However, there has been no report on the association between aflatoxin exposure and micronutrient deficiencies in HIV-infected people. We measured aflatoxin B<sub>1 </sub>albumin (AF-ALB) adduct levels and vitamins A and E concentrations in the plasma of HIV-positive and HIV-negative Ghanaians and examined the association of vitamins A and E with HIV status, aflatoxin levels and hepatitis B virus (HBV) infection.</p> <p>Methods</p> <p>A cross-sectional study was conducted in which participants completed a demographic survey and gave a 20 mL blood sample for analysis of AF-ALB levels, vitamins A and E concentrations, CD4 counts, HIV viral load and HBV infection.</p> <p>Results</p> <p>HIV-infected participants had significantly higher AF-ALB levels (median for HIV-positive and HIV-negative participants was 0.93 and 0.80 pmol/mg albumin, respectively; p <0.01) and significantly lower levels of vitamin A (-16.94 μg/dL; p <0.0001) and vitamin E (-0.22 mg/dL; p <0.001). For the total study group, higher AF-ALB was associated with significantly lower vitamin A (-4.83 μg/dL for every 0.1 pmol/mg increase in AF-ALB). HBV-infected people had significantly lower vitamin A (-5.66 μg/dL; p = 0.01). Vitamins A and E levels were inversely associated with HIV viral load (p = 0.02 for each), and low vitamin E was associated with lower CD4 counts (p = 0.004).</p> <p>Conclusions</p> <p>Our finding of the significant decrease in vitamin A associated with AF-ALB suggests that aflatoxin exposure significantly compromises the micronutrient status of people who are already facing overwhelming health problems, including HIV infection.</p
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