297 research outputs found

    Observers and Measurements in Noncommutative Spacetimes

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    We propose a "Copenhagen interpretation" for spacetime noncommutativity. The goal is to be able to predict results of simple experiments involving signal propagation directly from commutation relations. A model predicting an energy dependence of the speed of photons of the order E/E_Planck is discussed in detail. Such effects can be detectable by the GLAST telescope, to be launched in 2006.Comment: 10 pp; v2: equivalence of observers explicitely stated; v3: minor changes, references and remarks added, burst spreading with energy emphasized as a signature rather than nois

    Warped Phenomenology of Higher-Derivative Gravity

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    We examine the phenomenological implications at colliders for the existence of higher-derivative gravity terms as extensions to the Randall-Sundrum model. Such terms are expected to arise on rather general grounds, e.g., from string theory. In 5-d, if we demand that the theory be unitary and ghost free, these new contributions to the bulk action are uniquely of the Gauss-Bonnet form. We demonstrate that the usual expectations for the production cross section and detailed properties of graviton Kaluza-Klein resonances and TeV-scale black holes can be substantially altered by existence of these additional contributions. It is shown that measurements at future colliders will be highly sensitive to the presence of such terms.Comment: 29 pages, 8 figure

    Ethnic model of consumer practices tatars and Russians of republic of tatarstan in the period of globalization

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    © 2015, Review of European Studies. All right reserved. The purpose of this article is the comparative analysis of models of consumer practices of Tatars and Russians of the multiethnic region (Republic of Tatarstan, Russia) in the situation of globalization of consumer culture. The problem of modeling consumer practices of ethnic groups considered in the concept of economic anthropology (ethnology). It is concluded that a combination of two opposing processes within consumer practices of ethnic groups in the context of globalization: the erosion of ethno-cultural space and the revival of ethnic and cultural traditions. Value profiles of consumers working age of two ethnic groups of Tatarstan-Tatars and Russians, using the technique of LOV (List of Values), are constructed. Also value profiles further investigated by gender. Constructed value profiles of Tatars and Russians is one of the elements of the model of consumer practices of these ethnic groups. Consumer practices are constantly under the influence of external and internal factors, and their systematic study is the task of further work. Regular monitoring of the dynamics of the consumer practices of ethnic groups allows to monitor the socio-cultural and socio-economic processes in the interests of both the market subjects as well as various social groups

    Historical and cultural aspects of paganism among the peoples of tatarstan

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    Copyright © 2016 by Sochi State University.On the basis of the literature and field data the authors examine the phenomenon of "paganism" (traditional folk belief) among the Turkic (the Chuvashs) and Finnish (the Mari, the Udmurts) peoples of Tatarstan in the context of historical and ethno-cultural processes in the Volga-Urals region. There shown the history of the emergence of groups of "pagans" in Tatarstan, placing of their settlements, history of research in different periods (pre-revolutionary, Soviet and post-Soviet), the results of inter-confessional and inter-ethnic interactions in the formation of religious practices of "pagans" in the past and the present. Authors have marked objective and subjective factors in preserving the cultural and religious traditions, among them - The relative geographical and demographic isolation; predominantly rural style of life; the continuity of religious practices; "personality" factors. The conclusion of the favorable prospects for the development of ethnic and religious groups of the pagans, based on sufficient domestic capacity of communities and external public support for their ethnic and cultural distinctiveness was made

    New DRIE-Patterned Electrets for Vibration Energy Harvesting

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    This paper is about a new manufacturing process aimed at developing stable SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE) step for an application in electret-based Vibration Energy Harvesters (e-VEH). This process consists in forming continuous layers of SiO2/Si3N4 electrets in order to limit surface conduction phenomena and is a new way to see the problem of electret patterning. Experimental results prove that patterned electrets charged by a positive corona discharge show excellent stability with high surface charge densities that may reach 5mC/m^2 on 1.1\mu m-thick layers, even with fine patterning and harsh temperature conditions (up to 250{\deg}C). This paves the way to new e-VEH designs and manufacturing processes.Comment: Proc. European Energy Conference, 201

    Radiation Problem in Transplanckian Scattering

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    We investigate hard radiation emission in small-angle transplanckian scattering. We show how to reduce this problem to a quantum field theory computation in a classical background (gravitational shock wave). In momentum space, the formalism is similar to the flat-space light cone perturbation theory, with shock wave crossing vertices added. In the impact parameter representation, the radiating particle splits into a multi-particle virtual state, whose wavefunction is then multiplied by individual eikonal factors. As a phenomenological application, we study QCD radiation in transplanckian collisions of TeV-scale gravity models. We derive the distribution of initial state radiation gluons, and find a suppression at large transverse momenta with respect to the standard QCD result. This is due to rescattering events, in which the quark and the emitted gluon scatter coherently. Interestingly, the suppression factor depends on the number of extra dimensions and provides a new experimental handle to measure this number. We evaluate the leading-log corrections to partonic cross-sections due to the initial state radiation, and prove that they can be absorbed into the hadronic PDF. The factorization scale should then be chosen in agreement with an earlier proposal of Emparan, Masip, and Rattazzi. In the future, our methods can be applied to the gravitational radiation in transplanckian scattering, where they can go beyond the existing approaches limited to the soft radiation case.Comment: 41 pp, v2: minor changes and added refs, conforms with published versio

    Uranium stripping from tri-n-butyl phosphate by hydrogen peroxide solutions

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    The processes of uranium stripping from 30% tri-n-butyl phosphate (TBP) in "odorless" kerosene by H2O2 solutions both with and without NH4OH added were investigated in the temperature range of 20-50 C and with a volumetric ratio of 1 between the organic and aqueous phases. The uranium was selectively precipitated in the form of uranium peroxide during stripping from the organic phase by hydrogen peroxide. The stripping of uranium increased with increasing H2O2 content, increasing temperature and increasing concentration of NH3 in the range of 0-15 g/L. The use of a heated solution (40 C) that contained 4 mol H 2O2/mol U and NH3 12 g/L resulted in 99.7% of the uranium being stripped from TBP in the form of uranium peroxide. The uranium peroxide obtained by stripping is a highly pure product that exists in two different hydrated forms: UO4в̂™4H2O (92 mass %) and UO4в̂™2H2O. The mean particle diameter was 20.75 μm. The effect of hydrogen peroxide on the organic phase was studied by IR spectroscopy. No structural changes in TBP were observed after 30 cycles of extraction/stripping; thus, the use of hydrogen peroxide in this application is unrestricted. © 2013 Elsevier B.V

    Classical paradoxes of locality and their possible quantum resolutions in deformed special relativity

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    In deformed or doubly special relativity (DSR) the action of the lorentz group on momentum eigenstates is deformed to preserve a maximal momenta or minimal length, supposed equal to the Planck length. The classical and quantum dynamics of a particle propagating in kappa-Minkowski spacetime is discussed in order to examine an apparent paradox of locality which arises in the classical dynamics. This is due to the fact that the Lorentz transformations of spacetime positions of particles depend on their energies, so whether or not a local event, defined by the coincidence of two or more particles, takes place appears to depend on the frame of reference of the observer. Here it is proposed that the paradox arises only in the classical picture, and may be resolved when the quantum dynamics is taken into account. If so, the apparent paradoxes arise because it is inconsistent to study physics in which Planck's constant is zero but the Planck length is non-vanishing. This may be relevant for phenomenology such as observations by FERMI, because at leading order there is both a direct and a stochastic dependence of arrival time on energy, due to an additional spreading of wavepackets.Comment: LaTeX, 28 pages, no figures, substantially revise

    Spinning Conformal Correlators

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    We develop the embedding formalism for conformal field theories, aimed at doing computations with symmetric traceless operators of arbitrary spin. We use an index-free notation where tensors are encoded by polynomials in auxiliary polarization vectors. The efficiency of the formalism is demonstrated by computing the tensor structures allowed in n-point conformal correlation functions of tensors operators. Constraints due to tensor conservation also take a simple form in this formalism. Finally, we obtain a perfect match between the number of independent tensor structures of conformal correlators in d dimensions and the number of independent structures in scattering amplitudes of spinning particles in (d+1)-dimensional Minkowski space.Comment: 46 pages, 3 figures; V2: references added; V3: tiny misprint corrected in (A.9

    Neurogenic potential of dental pulp stem cells isolated from murine incisors

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    INTRODUCTION: Interest in the use of dental pulp stem cells (DPSC) to enhance neurological recovery following stroke and traumatic injury is increasing following successful pre-clinical studies. A murine model of autologous neural stem cell transplantation would be useful for further pre-clinical investigation of the underlying mechanisms. However, while human-derived DPSC have been well characterised, the neurogenic potential of murine DPSC (mDPSC) has been largely neglected. In this study we demonstrate neuronal differentiation of DPSC from murine incisors in vitro. METHODS: mDPSC were cultured under neuroinductive conditions and assessed for neuronal and glial markers and electrophysiological functional maturation. RESULTS: mDPSC developed a neuronal morphology and high expression of neural markers nestin, ßIII-tubulin and GFAP. Neurofilament M and S100 were found in lower abundance. Differentiated cells also expressed protein markers for cholinergic, GABAergic and glutaminergic neurons, indicating a mixture of central and peripheral nervous system cell types. Intracellular electrophysiological analysis revealed the presence of voltage-gated L-type Ca2+ channels in a majority of cells with neuronal morphology. No voltage-gated Na+ or K+ currents were found and the cultures did not support spontaneous action potentials. Neuronal-like networks expressed the gap junction protein, connexin 43 but this was not associated with dye coupling between adjacent cells after injection of the low-molecular weight tracers Lucifer yellow or Neurobiotin. This indicated that the connexin proteins were not forming traditional gap junction channels. CONCLUSIONS: The data presented support the differentiation of mDPSC into immature neuronal-like networks.Kylie M Ellis, David C O, Carroll, Martin D Lewis, Grigori Y Rychkov and Simon A Kobla
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