1,002 research outputs found

    The white dwarf in dwarf nova SDSS J080434.20+510349.2: Entering the instability strip?

    Full text link
    SDSS J080434.20+510349.2 is the WZ type binary that displayed rare outburst in 2006 (Pavlenko et al., 2007). During the long-lasting tail of the late stage of the outburst binary shown the two-humped or four-humped profile of the orbital light modulation. The amplitude of orbital light curve decreased while the mean brightness decreased, more over that occurred \sim 10 times faster during the fast outburst decline in respect to the late quiet state of slow outburst fading. There were no white dwarf pulsations detected neither 1 - 1.5 months prior to the outburst nor in 1.5 - 2 months after the 2006 outburst in this system. However the strong non-radial pulsations with period 12.6 minutes and mean amplitude of 0.05^m were first detected in V band with 2.6-m Shajn mirror telescope of the Crimean astrophysical observatory in ~ 8 months after the outburst. The evolution of pulsations over two years in 2006 - 2008 is considered. It is supposed that pulsations first appeared when the cooling white dwarf (after the outburst) entered the instability strip although the possibility of temporary lack of pulsations at some occasions also could not be excluded.Comment: Submitted to Proceedings of 16th European White Dwarf Workshop (EUROWD08

    Superconductivity Controlled by Polarization in Field-Effect Devices of Confined Geometry

    Full text link
    We propose a concept for superconducting electric field-effect devices based on superconducting films sandwiched between ferroelectric layers. We provide theoretical calculations that indicate how the field effect in these devices could be amplified, which can be experimentally probed even at the current stage of film fabrication techniques.Comment: to appear in Applied Physics Letters, 3 pages RevTeX4, 3 figure

    Modulation of Superconducting Properties by Ferroelectric Polarization in Confined FE-S-FE Films

    Full text link
    We show that the electric polarization at the interface with ultrathin superconducting (S) films sandwiched between ferroelectric (FE) layers allows achievement of substantially stronger modulation of inner carrier density and superconducting transition temperature as compared to FE-S bilayers typically used in superconducting FETs. We find that not only the larger penetration depths but also the pairing symmetry should be responsible for the fact that the electric field effect in high temperature superconductors is much stronger than in conventional systems. Discussing the advantages of multilayers, we propose a novel design concept for superconducting electric field-effect transistors based on ferroelectric films.Comment: 5 pages RevTex4, 6 figure

    Lessons from Non-Abelian Plasma Instabilities in Two Spatial Dimensions

    Full text link
    Plasma instabilities can play a fundamental role in quark-gluon plasma equilibration in the high energy (weak coupling) limit. Early simulations of the evolution of plasma instabilities in non-abelian gauge theory, performed in one spatial dimension, found behavior qualitatively similar to traditional QED plasmas. Later simulations of the fully three-dimensional theory found different behavior, unlike traditional QED plasmas. To shed light on the origin of this difference, we study the intermediate case of two spatial dimensions. Depending on how the "two-dimensional'' theory is formulated, we can obtain either behavior.Comment: 15 pages, 10 figure

    The Abelianization of QCD Plasma Instabilities

    Full text link
    QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what non-linear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge-fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities in the non-linear regime may have close parallels to similar processes in traditional plasma physics. We conjecture that the physics of collisionless plasma instabilities in SU(2) and SU(3) gauge theory becomes equivalent, respectively, to (i) traditional plasma physics, which is U(1) gauge theory, and (ii) plasma physics of U(1)x U(1) gauge theory.Comment: 36 pages; 15 figures [minor changes made to text, and new figure added, to reflect published version

    Bilingual episodic memory: an introduction

    Get PDF
    Our current models of bilingual memory are essentially accounts of semantic memory whose goal is to explain bilingual lexical access to underlying imagistic and conceptual referents. While this research has included episodic memory, it has focused largely on recall for words, phrases, and sentences in the service of understanding the structure of semantic memory. Building on the four papers in this special issue, this article focuses on larger units of episodic memory(from quotidian events with simple narrative form to complex autobiographical memories) in service of developing a model of bilingual episodic memory. This requires integrating theory and research on how culture-specific narrative traditions inform encoding and retrieval with theory and research on the relation between(monolingual) semantic and episodic memory(Schank, 1982; Schank & Abelson, 1995; Tulving, 2002). Then, taking a cue from memory-based text processing studies in psycholinguistics(McKoon & Ratcliff, 1998), we suggest that as language forms surface in the progressive retrieval of features of an event, they trigger further forms within the same language serving to guide a within-language/ within-culture retrieval

    Topical form work on prevention of psychoactive substances young people in the context of information technology

    Full text link
    On the basis of a number of sociological studies proved the relevance of the work on prevention substance use among young people. The information provided indicates that the Internet and, in particular, social networks, provide great potential to form the basis of self-preservation behavior among young people and other groups.На основе ряда социологических исследований доказывается актуальность работы по профилактике употребления психоактивных веществ среди молодежи. Представленная информация свидетельствует о том, что Интернет и, в частности, социальные сети, содержат большой потенциал для формирования основ самосохранительного поведения среди молодежи и других категорий населения

    Magnetism and superconductivity at LAO/STO-interfaces: the role of Ti 3d interface electrons

    Full text link
    Ferromagnetism and superconductivity are in most cases adverse. However, recent experiments reveal that they coexist at interfaces of LaAlO3 and SrTiO3. We analyze the magnetic state within density functional theory and provide evidence that magnetism is not an intrinsic property of the two-dimensional electron liquid at the interface. We demonstrate that the robust ferromagnetic state is induced by the oxygen vacancies in SrTiO3- or in the LaAlO3-layer. This allows for the notion that areas with increased density of oxygen vacancies produce ferromagnetic puddles and account for the previous observation of a superparamagnetic behavior in the superconducting state.Comment: 5 pages, 4 figures, to appear in Physical Review B (Rapid Communications

    Socio-cultural analysis of the phenomenon of mobile health in the context of information technology

    Full text link
    Мобильность является одним из символов современной жизни, в которой значимым остается здоровье человека. Соединение технических инноваций и здоровья порождает новые социальные явления, которые автор рассматривает в рамках данной статьи.Mobility is one of the symbols of modern life, which remains a significant human health. Connection technological innovation and health creates new social phenomena, which the author considers the scope of this article
    corecore