19,756 research outputs found

    Background effects on reconstructed WIMP couplings

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    In this talk, I presented effects of small, but non-negligible unrejected background events on the determinations of WIMP couplings/cross sections.Comment: 4 pages, 5 eps figures, to appear in the proceedings of the 12th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2011), September 5-9, 2011, Munich, German

    Determining Ratios of WIMP-Nucleon Cross Sections from Direct Dark Matter Detection Data

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    Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. So far the usual procedure for constraining the WIMP-nucleon cross sections in direct Dark Matter detection experiments have been to fit the predicted event rate based on some model(s) of the Galactic halo and of WIMPs to experimental data. One has to assume whether the spin-independent (SI) or the spin-dependent (SD) WIMP-nucleus interaction dominates, and results of such data analyses are also expressed as functions of the as yet unknown WIMP mass. In this article, I introduce methods for extracting information on the WIMP-nucleon cross sections by considering a general combination of the SI and SD interactions. Neither prior knowledge about the local density and the velocity distribution of halo WIMPs nor about their mass is needed. Assuming that an exponential-like shape of the recoil spectrum is confirmed from experimental data, the required information are only the measured recoil energies (in low energy ranges) and the number of events in the first energy bin from two or more experiments.Comment: 33 pages, 20 eps figures; v2: typos fixed, references added and updated, revised version for publicatio

    Analyzing direct dark matter detection data with unrejected background events by the AMIDAS website

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    In this talk I have presented the data analysis results of extracting properties of halo WIMPs: the mass and the (ratios between the) spin-independent and spin-dependent couplings/cross sections on nucleons by the AMIDAS website by taking into account possible unrejected background events in the analyzed data sets. Although non-standard astronomical setup has been used to generate pseudodata sets for our analyses, it has been found that, without prior information/assumption about the local density and velocity distribution of halo Dark Matter, these WIMP properties have been reconstructed with ~ 2% to <~ 30% deviations from the input values.Comment: 9 pages, 10 eps figures, 1 table, to appear in the proceedings of the Seventh International Workshop on the Dark Side of the Universe (DSU 2011), September 26-30, 2011, Beijing, Chin

    Signal Recognition Particle (SRP) and SRP Receptor: A New Paradigm for Multistate Regulatory GTPases

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    The GTP-binding proteins or GTPases comprise a superfamily of proteins that provide molecular switches in numerous cellular processes. The “GTPase switch” paradigm, in which a GTPase acts as a bimodal switch that is turned “on” and “off” by external regulatory factors, has been used to interpret the regulatory mechanism of many GTPases for more than two decades. Nevertheless, recent work has unveiled an emerging class of “multistate” regulatory GTPases that do not adhere to this classical paradigm. Instead of relying on external nucleotide exchange factors or GTPase activating proteins to switch between the on and off states, these GTPases have the intrinsic ability to exchange nucleotides and to sense and respond to upstream and downstream factors. In contrast to the bimodal nature of the GTPase switch, these GTPases undergo multiple conformational rearrangements, allowing multiple regulatory points to be built into a complex biological process to ensure the efficiency and fidelity of the pathway. We suggest that these multistate regulatory GTPases are uniquely suited to provide spatial and temporal control of complex cellular pathways that require multiple molecular events to occur in a highly coordinated fashion

    The effects of an individual, multistep intervention on adherence to treatment in hemodialysis patients

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    Purpose: The present study was conducted to investigate the effect of individual, multistep intervention on adherence to treatment in hemodialysis patients referred to a hemodialysis center in Shahrekord, Iran. Method: In this interventional study, hemodialysis patients referring the center of the study were randomly assigned into two control and intervention groups (each 33). The control group received routine treatment, recommended dietary and fluid restrictions. The intervention group participated in eight individual interventional sessions accompanied routine treatment. At the beginning and the end of the study, routine laboratory tests and end-stage renal disease-adherence questionnaire were filled out for patients in both groups. The data were analyzed using Mann-Whitney and Wilcoxon tests. Results: At the end of the study, the two groups showed a significant difference in all domains of adherence except adherence to diet and adherence was better in the intervention group (p < 0.05). In demographic characteristic, only age indicated a positive correlation with adherence to dialysis program (p = 0.04, r = 0.254). After intervention, serum phosphorus decreased significantly in the intervention group (p < 0.05). Conclusions: Adherence to treatment is one of the major problems in hemodialysis patients; however, comprehensive interventions are required in view of individual condition. ▸ Implications for Rehabilitation • Adherence to treatment means that all patients behaviors (diet, fluids and drugs intake) should be in line with the recommendations given by healthcare professionals. • There is evidence on the association between adherence to treatment and decreased risk of hospitalization in dialysis patients. • Individual structured programs are most likely to be successful in encouraging adherence to treatment. © 2015 Informa UK Ltd. All rights reserved

    Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass

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    In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ~20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ~10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94 GeV^{+55%}_{-33%} for background-free data sets).Comment: 27 pages, 22 eps figures; v2: revised version for publication, references added and update

    W±HW^{\pm}H^{\mp} associated production at LHC in the general 2HDM with Spontaneous CP Violation

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    Spontaneous CP violation motivates the introduction of two Higgs doublets in the electroweak theory. Such a simple extension of the standard model has three neutral Higgs bosons and a pair charged Higgs, especially it leads to rich CP-violating sources including the induced Kobayashi-Maskawa CP-violating phase, the mixing of the neutral Higgs bosons due to the CP-odd Higgs and the effective complex Yukawa couplings of the charged and neutral Higgs bosons. Within this model, we present the production of a charged Higgs boson in association with a W boson at the LHC, and calculate in detail the cross section and the transverse momentum distribution of the associated W boson.Comment: 16 pages, 6 figures, omitted 3 figures, motivations for Type III 2HDM with SCPV is emphasized, to be published in PR
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