36,912 research outputs found

    Digitale Langzeitarchivierung als Thema internationaler Institutionen und Organisationen : Ein bibliotheksorientierter Überblick

    Get PDF
    Long-term digital archiving is not only the concern of numerous national organizations, but also the topic of international institutions and projects. This article takes a survey and comments on the relevant activities of thirteen international and european organizations which are involved with education and information as a whole or librarianship in particular. These have dealt till now, however, primarily – sometimes multi-tracked – with fundamental or theoretical questions; the implementation of practical solutions has been rare and may well be left for the future. (journal editor's abstract

    Electrodynamics of superconductors

    Full text link
    An alternate set of equations to describe the electrodynamics of superconductors at a macroscopic level is proposed. These equations resemble equations originally proposed by the London brothers but later discarded by them. Unlike the conventional London equations the alternate equations are relativistically covariant, and they can be understood as arising from the 'rigidity' of the superfluid wave function in a relativistically covariant microscopic theory. They predict that an internal 'spontaneous' electric field exists in superconductors, and that externally applied electric fields, both longitudinal and transverse, are screened over a London penetration length, as magnetic fields are. The associated longitudinal dielectric function predicts a much steeper plasmon dispersion relation than the conventional theory, and a blue shift of the minimum plasmon frequency for small samples. It is argued that the conventional London equations lead to difficulties that are removed in the present theory, and that the proposed equations do not contradict any known experimental facts. Experimental tests are discussed.Comment: Small changes following referee's and editor's comments; to be published in Phys.Rev.

    The DLESE Community Review System: Gathering, Aggregating, and Disseminating User Feedback about the Effectiveness of Web-based Educational Resources

    Get PDF
    NOTE: This is a large file, 8 mb in size! The Community Review System (CRS) of the Digital Library for Earth System Education (DLESE) is intended to help educators seeking high-quality digital resources and resource creators who are seeking recognition for their resources. This article describes how CRS gathers web-based feedback from educators and learners who have used DLESE educational resources, plus specialist reviews by science and pedagogy experts. This information is used to identify exemplary resources to be showcased in the DLESE Reviewed Collection. Detailed, but anonymous, feedback is provided to the resource creator to encourage improvement of the resource. Educational levels: Graduate or professional, Graduate or professional

    Editor’s Note

    Get PDF
    Denna studie Ă€mnar att beskriva hur kunskapsintensiva företag hanterar den kunskap som konsulter bidrar med vid introduktion, i det dagliga arbetet och hur de möjliggör för överföring av kunskapen nĂ€r konsulten lĂ€mnar företaget. En fallstudie pĂ„ tvĂ„ stora internationella företag har genomförts och empiri samlades in genom semistrukturerade intervjuer. Resultatet visar att företagen har likartade introduktioner med fokus pĂ„ organisatoriska och individuella kunskaper. Vilket syfte konsulten har i företaget pĂ„verkar kunskapsintegreringen inom arbetet. Även organisationsstrukturen och konsultens placering inom företaget har effekter för kunskapsintegreringen. Konsulten bidrar med flexibilitet, vilket innebĂ€r att företaget bör strĂ€va efter att genomföra integrerande praktiker under arbetets gĂ„ng, och inte fokusera pĂ„ överlĂ€mningen enbart nĂ€r konsulten lĂ€mnar företaget

    Editor\u27s Introduction (Review Symposium on \u3ci\u3eConverging Divergences: Worldwide Changes in Employment Systems\u3c/i\u3e)

    Get PDF
    [Excerpt] During the past two decades there have been significant changes in employment systems across industrialized countries. Converging Divergences: Worldwide Changes in Employment Systems, by Harry C. Katz and Owen Darbishire, examines changes since 1980 in employment practices in seven industrialized countries—the United States, the United Kingdom, Australia, Germany, Japan, Sweden, and Italy—with a focus on the automotive and telecommunications industries. Katz and Darbishire find that variations in employment patterns within these countries have been increasing over the past two decades. The increase in variation is not simply a result of a decline in union strength in some sectors of the economy; variation has increased within both union and nonunion sectors. Despite this within-country divergence, Katz and Darbishire find that employment systems across countries are converging toward four common patterns of work practices: a low-wage employment pattern; the human resource management (HRM) employment pattern; a Japanese-oriented employment pattern; and a joint team-based employment pattern. Significant differences in national employment-related institutions have resulted in some variation across countries in how these work patterns are implemented. Still, Katz and Darbishire find that there are many commonalities in the employment systems of the seven countries and in the processes through which these commonalities have developed

    Editor\u27s Introduction

    Get PDF
    The editor\u27s introduction to this issue

    From the Editor\u27s Desk

    Get PDF

    Quantum Multibaker Maps: Extreme Quantum Regime

    Full text link
    We introduce a family of models for quantum mechanical, one-dimensional random walks, called quantum multibaker maps (QMB). These are Weyl quantizations of the classical multibaker models previously considered by Gaspard, Tasaki and others. Depending on the properties of the phases parametrizing the quantization, we consider only two classes of the QMB maps: uniform and random. Uniform QMB maps are characterized by phases which are the same in every unit cell of the multibaker chain. Random QMB maps have phases that vary randomly from unit cell to unit cell. The eigenstates in the former case are extended while in the latter they are localized. In the uniform case and for large ℏ\hbar, analytic solutions can be obtained for the time dependent quantum states for periodic chains and for open chains with absorbing boundary conditions. Steady state solutions and the properties of the relaxation to a steady state for a uniform QMB chain in contact with ``particle'' reservoirs can also be described analytically. The analytical results are consistent with, and confirmed by, results obtained from numerical methods. We report here results for the deep quantum regime (large ℏ\hbar) of the uniform QMB, as well as some results for the random QMB. We leave the moderate and small ℏ\hbar results as well as further consideration of the other versions of the QMB for further publications.Comment: 17 pages, referee's and editor's comments addresse
    • 

    corecore