63 research outputs found

    Field localization in warped gauge theories

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    We present four-dimensional gauge theories that describe physics on five-dimensional curved (warped) backgrounds, which includes bulk fields with various spins (vectors, spinors, and scalars). Field theory on the AdS5_5 geometry is examined as a simple example of our formulation. Various properties of bulk fields on this background, e.g., the mass spectrum and field localization behavior, can be achieved within a fully four-dimensional framework. Moreover, that gives a localization mechanism for massless vector fields. We also consider supersymmetric cases, and show in particular that the conditions on bulk masses imposed by supersymmetry on warped backgrounds are derived from a four-dimensional supersymmetric theory on the flat background. As a phenomenological application, models are shown to generate hierarchical Yukawa couplings. Finally, we discuss possible underlying mechanisms which dynamically realize the required couplings to generate curved geometries.Comment: 24 pages, 12 figures; more explanation of nonuniversal gauge couplings added, typos corrected, references update

    Soft, collinear and non-relativistic modes in radiative decays of very heavy quarkonium

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    We analyze the end-point region of the photon spectrum in semi-inclusive radiative decays of very heavy quarkonium (m alpha_s^2 >> Lambda_QCD). We discuss the interplay of the scales arising in the Soft-Collinear Effective Theory, m, m(1-z)^{1/2} and m(1-z) for z close to 1, with the scales of heavy quarkonium systems in the weak coupling regime, m, m alpha_s and m alpha_s^2. For 1-z \sim alpha_s^2 only collinear and (ultra)soft modes are seen to be relevant, but the recently discovered soft-collinear modes show up for 1-z << alpha_s^2. The S- and P-wave octet shape functions are calculated. When they are included in the analysis of the photon spectrum of the Upsilon (1S) system, the agreement with data in the end-point region becomes excellent. The NRQCD matrix elements and are also obtained.Comment: Revtex, 11 pages, 6 figures. Minor improvements and references added. Journal versio

    A Phenomenological Analysis of Gluon Mass Effects in Inclusive Radiative Decays of the J/ψ\rm{J/\psi} and $\Upsilon

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    The shapes of the inclusive photon spectra in the processes \Jp \to \gamma X and \Up \to \gamma X have been analysed using all available experimental data. Relativistic, higher order QCD and gluon mass corrections were taken into account in the fitted functions. Only on including the gluon mass corrections, were consistent and acceptable fits obtained. Values of 0.7210.068+0.0160.721^{+0.016}_{-0.068} GeV and 1.180.29+0.091.18^{+0.09}_{-0.29} GeV were found for the effective gluon masses (corresponding to Born level diagrams) for the \Jp and \Up respectively. The width ratios \Gamma(V \to {\rm hadrons})/\Gamma(V \to \gamma+ {\rm hadrons}) V=\Jp, \Up were used to determine αs(1.5GeV)\alpha_s(1.5 {\rm GeV}) and αs(4.9GeV)\alpha_s(4.9 {\rm GeV}). Values consistent with the current world average αs\alpha_s were obtained only when gluon mass correction factors, calculated using the fitted values of the effective gluon mass, were applied. A gluon mass 1\simeq 1 GeV, as suggested with these results, is consistent with previous analytical theoretical calculations and independent phenomenological estimates, as well as with a recent, more accurate, lattice calculation of the gluon propagator in the infra-red region.Comment: 50 pages, 11 figures, 15 table

    Risk accelerators in disasters : insights from the typhoon Haiyan response on humanitarian information management and decision support

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    Published version of a chapter in the book: Advanced Information Systems Engineering. Also available from the publisher at: http://dx.doi.org/10.1007/978-3-319-07881-6_2Modern societies are increasingly threatened by disasters that require rapid response through ad-hoc collaboration among a variety of actors and organizations. The complexity within and across today's societal, economic and environmental systems defies accurate predictions and assessments of damages, humanitarian needs, and the impact of aid. Yet, decision-makers need to plan, manage and execute aid response under conditions of high uncertainty while being prepared for further disruptions and failures. This paper argues that these challenges require a paradigm shift: instead of seeking optimality and full efficiency of procedures and plans, strategies should be developed that enable an acceptable level of aid under all foreseeable eventualities. We propose a decision- and goal-oriented approach that uses scenarios to systematically explore future developments that may have a major impact on the outcome of a decision. We discuss to what extent this approach supports robust decision-making, particularly if time is short and the availability of experts is limited. We interlace our theoretical findings with insights from experienced humanitarian decision makers we interviewed during a field research trip to the Philippines in the aftermath of Typhoon Haiyan

    A 330 bp region of the spinach nitrite reductase gene promoter directs nitrate-inducible tissue-specific expression in transgenic tobacco.

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    Nitrite reductase is an enzyme in the nitrate assimilatory pathway whose expression is induced upon the addition of nitrate. Furthermore, it is known to be located in chloroplasts in leaves and plastids in roots. A 3.1 kb 5&prime; upstream region of the spinach nitrite reductase (NiR) gene promoter was shown previously to confer nitrate inducibility on the &beta;-glucuronidase (GUS) reporter gene expression in both the leaves and the roots of transgenic tobacco plants. In the present study, this 3.1 kb promoter fragment as well as a series of promoter deletion constructs, fused to a GUS gene, were utilized to delineate the region of NiR promoter involved in nitrate regulation of NiR expression by studying the cellular localization of NiR-GUS expression as well as its regulation by nitrate. In plants carrying the longest promoter fragment (-3100 from the transcription start site) and promoter sequences progressively deleted to -330 bp, the expression of GUS was markedly increased in the presence of nitrate, and this expression was found to occur in mesophyll cells in leaves and in the vascular tissues of stem and roots. When nitrate was added to NiR-GUS plants grown in the absence of nitrate, significant levels of GUS activity could be seen in the roots after 2 h and in the leaves after 6 h. Furthers 5&prime; deletion of the promoter to -200 bp abolished the nitrate induction of GUS expression, indicating that the 130 bp region of the nitrite reductase promoter located between -330 and -200 is required for full nitrate-inducible tissue-specific expression

    Isolation of the spinach nitrite reductase gene promoter which confers nitrate inducibility on GUS gene expression in transgenic tobacco.

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    Nitrite reductase is the second enzyme in the nitrate assimilatory pathway. The transcription of this gene is regulated by nitrate as well as a variety of other environmental and developmental factors. Genomic clones containing the entire nitrite reductase gene have been isolated from a spinach genomic library and sequenced. The sequence is identical in the transcribed region to a previously isolated spinach NiR cDNA clone (Back et al., 1988) except for the presence of three introns. The analysis of the genomic clones and DNA blot hybridization demonstrates that there is a single NiR gene per haploid genome in spinach. This is in contrast to what has been found for other plant species. The transcription initiation site has been determined by S1 mapping and the 5&prime; upstream region has been used to regulate the GUS reporter gene in transgenic tobacco plants. This gene was found to be regulated by the addition of nitrate in the transgenic plants

    Molekularbiologie der Senioren

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