22,705 research outputs found

    Coherent states for compact Lie groups and their large-N limits

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    The first two parts of this article surveys results related to the heat-kernel coherent states for a compact Lie group K. I begin by reviewing the definition of the coherent states, their resolution of the identity, and the associated Segal-Bargmann transform. I then describe related results including connections to geometric quantization and (1+1)-dimensional Yang--Mills theory, the associated coherent states on spheres, and applications to quantum gravity. The third part of this article summarizes recent work of mine with Driver and Kemp on the large-N limit of the Segal--Bargmann transform for the unitary group U(N). A key result is the identification of the leading-order large-N behavior of the Laplacian on "trace polynomials."Comment: Submitted to the proceeding of the CIRM conference, "Coherent states and their applications: A contemporary panorama.

    The Turkey Ig-like receptor family: identification, expression and function.

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    The chicken leukocyte receptor complex located on microchromosome 31 encodes the chicken Ig-like receptors (CHIR), a vastly expanded gene family which can be further divided into three subgroups: activating CHIR-A, bifunctional CHIR-AB and inhibitory CHIR-B. Here, we investigated the presence of CHIR homologues in other bird species. The available genome databases of turkey, duck and zebra finch were screened with different strategies including BLAST searches employing various CHIR sequences, and keyword searches. We could not identify CHIR homologues in the distantly related zebra finch and duck, however, several partial and complete sequences of CHIR homologues were identified on chromosome 3 of the turkey genome. They were designated as turkey Ig-like receptors (TILR). Using cDNA derived from turkey blood and spleen RNA, six full length TILR could be amplified and further divided according to the typical sequence features into one activating TILR-A, one inhibitory TILR-B and four bifunctional TILR-AB. Since the TILR-AB sequences all displayed the critical residues shown to be involved in binding to IgY, we next confirmed the IgY binding using a soluble TILR-AB1-huIg fusion protein. This fusion protein reacted with IgY derived from various gallinaceous birds, but not with IgY from other bird species. Finally, we tested various mab directed against CHIR for their crossreactivity with either turkey or duck leukocytes. Whereas no staining was detectable with duck cells, the CHIR-AB1 specific mab 8D12 and the CHIR-A2 specific mab 13E2 both reacted with a leukocyte subpopulation that was further identified as thrombocytes by double immunofluorescence employing B-cell, T-cell and thrombocyte specific reagents. In summary, although the turkey harbors similar LRC genes as the chicken, their distribution seems to be distinct with predominance on thrombocytes rather than lymphocytes

    R-parity violating resonant stop production at the Large Hadron Collider

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    We have investigated the resonant production of a stop at the Large Hadron Collider, driven by baryon number violating interactions in supersymmetry. We work in the framework of minimal supergravity models with the lightest neutralino being the lightest supersymmetric particle which decays within the detector. We look at various dilepton and trilepton final states, with or without b-tags. A detailed background simulation is performed, and all possible decay modes of the lighter stop are taken into account. We find that higher stop masses are sometimes easier to probe, through the decay of the stop into the third or fourth neutralino and their subsequent cascades. We also comment on the detectability of such signals during the 7 TeV run, where, as expected, only relatively light stops can be probed. Our conclusion is that the resonant process may be probed, at both 10 and 14 TeV, with the R-parity violating coupling {\lambda}"_{312} as low as 0.05, for a stop mass of about 1 TeV. The possibility of distinguishing between resonant stop production and pair-production is also discussed.Comment: 20 pages, 4 figures, 6 tables; Version accepted by JHE

    High strength and formable Mg-6.2Zn-0.5Zr-0.2Ca alloy sheet processed by twin roll casting

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    Twin roll cast and hot rolled Mg-6.2 wt%Zn alloys microalloyed with Zr, Ca, and Ag show tensile yield strength exceeding 300 MPa in the T6 (peak-aged) condition with reasonable formability in the T4 condition. The addition of Zr and Ca plays a critical role in the development of weak textured recrystallized microstructure in Mg-6.2 wt%Zn alloys so Mg-6.2Zn-0.5Zr-0.2Ca (wt%) alloy shows equivalent mechanical properties with Mg-6.2Zn-0.5Zr-0.2Ca-0.4Ag (wt%) alloy even without expensive Ag. (C) 2014 Elsevier B.V. All rights reserved.X112224Ysciescopu

    Exploring Consumers’ Attitudes of Smart TV Related Privacy Risks

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    A number of privacy risks are inherent in the Smart TV ecosystem. It is likely that many consumers are unaware of these privacy risks. Alternatively, they might be aware but consider the privacy risks acceptable. In order to explore this, we carried out an online survey with 200 participants to determine whether consumers were aware of Smart TV related privacy risks. The responses revealed a meagre level of awareness. We also explored consumers’ attitudes towards specific Smart TV related privacy risks. We isolated a number of factors that influenced rankings and used these to develop awareness-raising messages. We tested these messages in an online survey with 155 participants. The main finding was that participants were generally unwilling to disconnect their Smart TVs from the Internet because they valued the Smart TV’s Internet functionality more than their privacy. We subsequently evaluated the awareness-raising messages in a second survey with 169 participants, framing the question differently. We asked participants to choose between five different Smart TV Internet connection options, two of which retained functionality but entailed expending time and/or effort to preserve privacy

    Total material requirement for the global energy transition to 2050: A focus on transport and electricity

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    © 2019 The Author(s) Global energy transitions could fundamentally change flows of both minerals and energy resources over time. It is, therefore, increasingly important to holistically and dynamically capture the impacts of large-scale energy transitions on resource flows including hidden flows such as mine waste, as well as direct flows. Here we demonstrate a systematic model that can quantify resource flows of both minerals and energy resources under the energy transition by using stock-flow dynamics and the concept of Total Material Requirement (TMR). The proposed model was applied to the International Energy Agency's scenarios up to 2050, targeting 15 electricity generation and 5 transport technologies. Results indicate that the global energy transition could increase TMR flows associated with mineral production by around 200–900% in the electricity sector and 350–700% in the transport sector respectively from 2015 to 2050, depending on the scenarios. Such a drastic increase in TMR flows is largely associated with an increased demand for copper, silver, nickel, lithium and cobalt, as well as steel. Our results highlight that the decarbonization of the electricity sector can reduce energy resource flows and support the hypothesis that the expansion of low-carbon technologies could reduce total resource flows expressed as TMR. In the transport sector, on the other hand, the dissemination of Electric Vehicles could cause a sharp increase in TMR flows associated with mineral production, which could offset a decrease in energy resource flows. Findings in this study emphasize that a sustainable transition would be unachievable without designing resource cycles with a nexus approach

    Yukawa unification in SO(10) with light sparticle spectrum

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    We investigate supersymmetric SO(10) GUT model with \mu<0. The requirements of top-bottom-tau Yukawa unification, correct radiative electroweak symmetry breaking and agreement with the present experimental data may be met when the soft masses of scalars and gauginos are non-universal. We show how appropriate non-universalities can easily be obtained in the SO(10) GUT broken to the Standard Model. We discuss how values of BR(b-->s \gamma) and (g-2)_\mu simultaneously in a good agreement with the experimental data can be achieved in SO(10) model with \mu<0. In the region of the parameter space preferred by our analysis there are two main mechanisms leading to the LSP relic abundance consistent with the WMAP results. One is the co-annihilation with the stau and the second is the resonant annihilation via exchange of the Z boson or the light Higgs scalar. A very interesting feature of SO(10) models with negative \mu is that they predict relatively light sparticle spectra. Even the heaviest superpartners may easily have masses below 1.5 TeV in contrast to multi-TeV particles typical for models with positive \mu.Comment: 23 pages, 5 figure

    Resting electrocardiographic and echocardiographic findings in an urban community in the Gambia

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    The presence of Left Ventricular Hypertrophy (LVH) in a patient with systemic hypertension deserves serious attention and makes its clinical diagnosis a priority. Over the years various criteriahave been proposed for the electrographic (ECG) diagnosis of LVH and the sensitivity and specificity of these criteria have been extensively studied in Caucasians. Recent evidence indicates that they areinapplicable to people of African descent. Unlike echocardiography (ECHO), the ECG is generally available, cheap but has a lower sensitivity in detecting LVH compared to echocardiography. Thisstudy was conducted to evaluate ECG criteria against 2-dimensional (2-D) guided M-mode echocardiography in the diagnosis of LVH in adult Gambians. Secondly, to determine the ECG criteria usingthe Minnesota, Araoye, Sokolow and Lyon or Wolff criteria with the overall best accuracy for the diagnosis of LVH. Two hundred and eight (208) consecutive patients with systemic hypertension (BP.140/90mmHg) with or without treatment and an age matched group of 108 non-hypertensive patients were enrolled from outpatient clinics. A questionnaire was filled. All patients were investigated with 2-D guided M-mode echocardiography and a standard 12-1ead ECG. Anthropometric measurements were also taken. The gold standard was the Penn formula to determine the left ventricular mass index (of 125 g/m2 in males and 110 g/m2 in females as the cut-off for LVH). Using this gold standard the prevalence of echocardiographic LVH was 47.5% and 27.8 % in the hypertensives and non-hypertensives respectively (P 0.05). Sokolow and Lyon criterion had overall best accuracy for the electrocardiographic diagnosis of left ventricular hypertrophyin hypertensives and is further recommended for use as such. But for non-hypertensives, the Wolff criterion had overall best accuracy

    On SUSY GUTs with a degenerate Higgs mass matrix

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    Certain supersymmetric grand unified models predict that the coefficients of the quadratic terms in the MSSM Higgs potential should be degenerate at the GUT scale. We discuss some examples for such models, and we analyse the implications of this peculiar condition of a GUT-scale degenerate Higgs mass matrix for low-scale MSSM phenomenology. To this end we explore the parameter space which is consistent with existing experimental constraints by means of a Markov Chain Monte Carlo analysis.Comment: 31 pages, 27 figures; v2: typos correcte
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