2,484 research outputs found

    Spin Axioms in Relativistic Continuum Physics

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    The 24 components of the relativistic spin tensor consist of 3+3 basic spin fields and 9+9 constitutive fields. Empirically only 3 basic spin fields and 9 constitutive fields are known. This empirem can be expressed by two spin axioms, one of them identifying 3 spin fields, and the other one 9 constitutive fields to each other. This identification by the spin axioms is material-independent and does not mix basic spin fields with constitutive properties. The approaches to the Weyssenhoff fluid and the Dirac-electron fluid found in literature are discussed with regard to these spin axioms. The conjecture is formulated, that another reduction from 6 to 3 basic spin fields which does not obey the spin axioms introduces special material properties by not allowed mixing of constitutive and basic fields.Comment: 15 pages, dirac-electron example has been rewritte

    The Distribution of Stock Return Volatility

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    We exploit direct model-free measures of daily equity return volatility and correlation obtained from high-frequency intraday transaction prices on individual stocks in the Dow Jones Industrial Average over a five-year period to confirm, solidify and extend existing characterizations of stock return volatility and correlation We find that the unconditional distributions of the variances and covariances for all thirty stocks are leptokurtic and highly skewed to the right, while the logarithmic standard deviations and correlations all appear approximately Gaussian. Moreover, the distributions returns scaled by the realized standard deviations are also Gaussian. Furthermore, the realized logarithmic standard deviations and correlations all show strong dependence and appear to be well described by long-memory processes, consistent with our documentation of remarkably precise scaling laws under temporal aggregation. Our results also show that positive returns have less impact on future variances and correlations than negative returns of the same absolute magnitude, although the economic importance of this asymmetry is minor. Finally, there is strong evidence that equity volatilities and correlations move together, thus diminishing the benefits to diversification when the market is most volatile. By explicitly incorporating each of these stylized facts, our findings set the stage for improved high-dimensional volatility modeling and out-of-sample forecasting, which in turn hold promise for the development of better decision making in practical situations of risk management, portfolio allocation, and asset pricing.

    The Distribution of Stock Return Volatility

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    We exploit direct model-free measures of daily equity return volatility and correlation obtained from high-frequency intraday transaction prices on individual stocks in the Dow Jones Industrial Average over a five-year period to confirm, solidify and extend existing characterizations of stock return volatility and correlation. We find that the unconditional distributions of the variances and covariances for all thirty stocks are leptokurtic and highly skewed to the right, while the logarithmic standard deviations and correlations all appear approximately Gaussian. Moreover, the distributions of the returns scaled by the realized standard deviations are also Gaussian. Consistent with our documentation of remarkably precise scaling laws under temporal aggregation, the realized logarithmic standard deviations and correlations all show strong temporal dependence and appear to be well described by long-memory processes. Positive returns have less impact on future variances and correlations than negative returns of the same absolute magnitude, although the economic importance of this asymmetry is minor. Finally, there is strong evidence that equity volatilities and correlations move together, possibly reducing the benefits to portfolio diversification when the market is most volatile. Our findings are broadly consistent with a latent volatility fact or structure, and they set the stage for improved high-dimensional volatility modeling and out-of-sample forecasting, which in turn hold promise for the development of better decision making in practical situations of risk management, portfolio allocation, and asset pricing.

    Пространство эстетизации повседневных жизненных практик:динамика, противоречия, социальный контекст

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    Научно-квалификационная работа посвящена актуальной проблеме, обусловленной дискуссионным характером социокультурных изменений, вызванных "пространственным поворотом", эстетизацией повседневности и обществом переживаний. Эстетизация, затрагивающая все сферы человеческой деятельности, и дигитализация, меняющая способ коммуникации современного индивида и формирующая новый "фокус" восприятия мира, определяют современное "общество переживаний" и "экономику впечатлений", трансформируют характер и цель социального взаимодействия, отношения человека с миром, ведут к смещению ценностных ориентиров. В работе дается характеристика концепций "общества переживаний", "экономики впечатлений", "эстетизация повседневности"; проанализирована эволюция этих идей.The scientific and qualification work is devoted to the actual problem, caused by the controversial nature of the sociocultural changes caused by the "spatial turn", aesthetisation of everyday life and the experience society. Aesthetization, affecting all spheres of human activity, and digitalization, changing the way of communication of a modern individual and forming a new "focus" of the world perception determine the modern "experience society" and " experience economy", transform the nature and purpose of social interaction, human relations with the world, lead to the displacement of value points. The work describes the concepts of the "experience society", " experience economy", " aesthetisation of everyday life "; The evolution of these ideas is analyzed

    Das Internet als Basis für die Produktinformation im Bauwesen

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    Die Gesamtheit der Produktinformationen im Bauwesen stellt sich als sehr inkonsistente und redundante Informationsmenge dar. Die Hersteller stehen vor der Aufgabe, diese Produktinformationen nicht nur in der üblichen Katalogform sondern auch in neuen Medien wie CD-ROM und WWW zu publizieren. Einmal betriebener Erfassungsaufwand muß sich dabei durch eine einfache Mehrfachverwendung der Daten rentieren. Wegen seiner technologischen Eigenschaften eignet sich das WWW sehr gut als primäre Quelle für Produktinformationen. Vor allem wegen der möglichen Aktualität sollte es Grundlage für Publikationen in den anderen Medien sein. Mit verhältnismäßig geringem Aufwand lassen sich die WWW-Präsentation von Produktdaten so strukturieren, daß eine automatisierte Erfassung und Verarbeitung dieser Daten vereinfacht wird. So kann die Datenkonsistenz von der visuellen Präsentation in herkömmlichen Katalogen bis zur automatisch erstellten Produktdatenbank durchgängig gesichert werden. Vor dem Hintergrund der von Schnittstellenproblemen, heterogener Softwarestruktur und unzureichender Ausnutzung der Möglichkeiten der Informatik gekennzeichneten Situation im Bauwesen wird in generalisierter Ansatz mittels SGML vorgestellt. Mit einem derartigen Datenangebot werden neue, verteilte und vernetzte Anwendungen auf Grundlage derselben Produktdaten ermöglicht

    Between Europeanism and Nativism: Exploring a Cleavage Model of European Public Sphere in Social Media

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    The European Union’s common public sphere project dates back to the 1960s and relies on Europeanisation through the gradual eradication of communication boundaries between its member countries. However, it is evident by now that Europeanisation of national public spheres is hard to achieve by increasing overlaps between national public spheres, synchronisation of news reporting across national boundaries, or diffusion of Europeanist norms into national politics. The European Union’s common public sphere project may hence be in danger. This calls for explorations of other imaginable models of the public sphere for Europe. Are there traces of other modes of transnational public sphere emerging in Europe? In this article, we explore a models of the transnational public sphere which is based on an alternative concept of Europeanisation derived from the cleavage theory. By drawing on social media data and employing tools of social network analysis, we demonstrate the empirical possibility of a cleavage model of the European public sphere.publishedVersio

    Comment on: Dynamic and Static Properties of the Randomly Pinned Flux Array

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    We reconsider the model of the randomly pinned planar flux array (or the two-dimensional XY-model with random fields and no vortices) in extensive Monte Carlo simulations. We show that contrary to what has been reported recently [Phys.\ Rev.\ Lett.\ {\bf 72}, 4133 (1994)] the disorder-averaged displacement correlation function is different from the pure case for larger values of the disorder. Its slope as a function of the logarithm of disorder is compatible with newer RG-calculation results.Comment: 6 pages, RevTeX, 2 postscript figures included as uuencoded Z-compressed .tar file created by uufile

    Bacterial feeding induces changes in immune-related gene expression and has trans-generational impacts in the cabbage looper (Trichoplusia ni)

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    <p>Abstract</p> <p>Background</p> <p>Poly- and oligophagous insects are able to feed on various host plants with a wide range of defense strategies. However, diverse food plants are also inhabited by microbiota differing in quality and quantity, posing a potential challenge for immune system mediated homeostasis in the herbivore. Recent studies highlight the complex interactions between environmentally encountered microorganisms and herbivorous insects, pointing to a potential adaptational alteration of the insects' physiology. We performed a differential gene expression analysis in whole larvae and eggs laid by parents grown on different diets to identify potential novel genes related to elevated microbial content in the caterpillars' food.</p> <p>Results</p> <p>We used GeneFishing, a novel differential display method, to study the effects of dietary bacteria on the general gene expression in different life stages and tissues of the cabbage looper (<it>Trichoplusia ni</it>). We were able to visualize several hundred transcripts on agarose gels, one fifth of which were differentially expressed between treatments. The largest number of differentially expressed genes was found in defense-related processes (13) and in recognition and metabolism (16). 21 genes were picked out and further tested for differential gene expression by an independent method (qRT-PCR) in various tissues of larvae grown on bacterial and bacteria-free diet, and also in adults. We detected a number of genes indicative of an altered physiological status of the insect, depending on the diet, developmental stage and tissue.</p> <p>Conclusion</p> <p>Changes in immune status are accompanied by specific changes in the transcript levels of genes connected to metabolism and homeostasis of the organism. Our findings show that larval feeding on bacteria-rich diet leads to substantial gene expression changes, potentially resulting in a reorganization of the insects' metabolism to maintain organismal homeostasis, not only in the larval but also in the adult stage. Furthermore, differences in gene expression levels can also be seen in the next generation, strongly influenced by parental diet.</p
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