421 research outputs found

    A Long Baseline Laser Strainmeter for the Exploratory Studies Facility at Yucca Mountain

    Full text link
    This Scientific Investigation Plan (SIP), for work under the second Department of Energy/University and Community College System of Nevada (DOE/UCCSN) Cooperative Agreement (10/01/03), DEFC28- 04RW12232, is intended to cover the laser strainmeter operation and monitoring task being conducted by the University of California, San Diego (UCSD), under the oversight of the Nevada Seismological Laboratory of the University of Nevada-Reno (NSL/UNR). UCSD has carried out the design, engineering, and installation of the east-west laser strainmeter (LSM) currently in place in the Exploratory Studies Facility (ESF) at Yucca Mountain

    Longbase laser strainmeter measurements from the South Ramp of the Yucca Mountain facility

    Full text link
    Under subcontract (DOE/UCCSN DE-FC28-98NV12081, Task 7) from the Seismological Laboratory of the University of Nevada-Reno, the University of California, San Diego (UCSD), has designed, installed, and operated a laser strainmeter (LSM) in the Exploratory Studies Facility (ESF) at Yucca Mountain, Nevada. This instrument provides precise deformation monitoring of the (proposed) repository block. This document describes the history of the installation, outlines the principles of operation of the system, documents the integral recording and control system and file formats used, and provides information on how QA has been implemented, with the aim of being a self-contained description which could be used (in conjunction with the data files at the TDMS) to understand the measurements made by the LSM. Appendix A gives the unique digital signatures for all data files submitted to the TDMS. The instrument was installed along the south wall of the tunnel, between 69+46 m and 65+41 m (tunnel coordinates). The resulting azimuth (91°) provides good sensitivity to the posited long-term strains from geologic sources. Designing an instrument for the tunnel was a challenge, as was installing it, given the usual, strict local operating procedures; these two elements combined to increase substantially the overall time to completion, though the experience gained has put us in a good position for further work in this setting. We have fully documented (SN) all aspects of the installation, and have complete engineering plans of the LSM available (Appendix B). The instrument began operating to QA standards on 2002:233 (August 21, 2002), and has recorded strain since that time, though with interruptions caused by the very strong shaking from the mining trains, which both caused sizeable gaps in the series and caused the lasers to degrade much more rapidly: both problems have been dealt with successfully. The instrument is producing quality records. Preliminary results from the laser strainmeter suggest that seismic waves and tides cause strains with no obvious anomalous response or nonlinearity; and that air-pressure changes can cause significant strains, with a response that depends on the spatial pattern of pressure applied. With the data so far available, we can constrain the long-term strain rate to be less than 0.2 /z£/yr. A longer-term record should greatly improve this constraint

    A randomised placebo-controlled Phase III multicentre trial: low-dose intravenous immunoglobulin treatment for long-standing complex regional pain syndrome (LIPS trial)

    Get PDF
    BACKGROUND: Complex regional pain syndrome (CRPS) is a rare, severe post-traumatic pain condition affecting distal limbs. Patients who do not spontaneously improve in 12 months are classed as having ‘long-standing CRPS’ and often cannot be effectively treated, leading to a poor prognosis. CRPS is associated with functional autoantibodies. Two small trials, including a randomised controlled trial, have suggested that low-dose intravenous immunoglobulin (IVIg) may be an effective treatment for some patients. OBJECTIVE: We hypothesised that low-dose IVIg is effective for reducing pain in long-standing CRPS. METHODS: A randomised, double blinded placebo-controlled multicentre trial in seven UK pain management centres. Patients were eligible if they had moderate or severe long-standing CRPS that they had experienced for up to 5 years. Participants were randomly allocated to receive 0.5 g/kg IVIg, the active intervention, or visually indistinguishable 0.1% albumin in saline placebo. Randomisation was initiated by study sites via an independent online randomisation system and was 1 : 1 with varying block sizes, stratified by study centre. Participants, investigators and assessors were blinded to group assignment. The study drug/placebo was infused intravenously at the study centres on day 1 and day 23 after randomisation. The primary outcome was the 24-hour average pain intensity between day 6 and day 42, on an 11-point (0–10) numeric rating scale, compared between the groups. Outcomes were analysed using a mixed-effects regression model that used 37 measurements of pain intensity (the primary outcome) per participant. All patients who received an infusion and provided any outcome were included in the intention-to-treat analysis. RESULTS: A total of 111 patients were recruited and assigned between 27 August 2013 and 28 October 2015. Three patients were excluded because they had been inappropriately randomised, five patients were withdrawn from the primary analysis because they provided no outcomes and 103 patients were analysed for the primary outcome. The average pain score in the IVIg group was 0.27 units (95% confidence interval –0.24 to 0.80 units) higher than in the placebo group. Therefore, there is no significant evidence of a treatment effect at the 5% level and there was no significant difference between groups. Six serious adverse events but no suspected unexpected serious adverse reactions were reported during the blinded and open-label phase. CONCLUSION AND FUTURE WORK: Low-dose immunoglobulin was not effective in relieving pain in patients with moderate to severe CRPS of 1–5 years’ duration. Better drug treatments for long-standing CRPS are urgently required. TRIAL REGISTRATION: Current Controlled Trials ISRCTN42179756. FUNDING: This project was funded by the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research partnership. Additional funding was obtained by the Pain Relief Foundation. Biotest UK Ltd provided the active study medication at no cost

    WMAP-Compliant Benchmark Surfaces for MSSM Higgs Bosons

    Get PDF
    We explore `benchmark surfaces' suitable for studying the phenomenology of Higgs bosons in the minimal supersymmetric extension of the Standard Model (MSSM), which are chosen so that the supersymmetric relic density is generally compatible with the range of cold dark matter density preferred by WMAP and other observations. These benchmark surfaces are specified assuming that gaugino masses m_{1/2}, soft trilinear supersymmetry-breaking parameters A_0 and the soft supersymmetry-breaking contributions m_0 to the squark and slepton masses are universal, but not those associated with the Higgs multiplets (the NUHM framework). The benchmark surfaces may be presented as M_A-tan_beta planes with fixed or systematically varying values of the other NUHM parameters, such as m_0, m_{1/2}, A_0 and the Higgs mixing parameter mu. We discuss the prospects for probing experimentally these benchmark surfaces at the Tevatron collider, the LHC, the ILC, in B physics and in direct dark-matter detection experiments. An Appendix documents developments in the FeynHiggs code that enable the user to explore for her/himself the WMAP-compliant benchmark surfaces.Comment: Minor corrections, references added. 43 pages, 10 figures. Version to appear in JHE

    Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

    Get PDF
    The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure

    Search for the standard model Higgs boson decaying to a bbˉb\bar{b} pair in events with no charged leptons and large missing transverse energy using the full CDF data set

    Get PDF
    We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at s=1.96\sqrt{s} = 1.96 TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb1^{-1}. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a bb quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and 150GeV/c2150 \mathrm{GeV}/c^2. For a Higgs boson mass of 125GeV/c2125 \mathrm{GeV}/c^2, the observed (expected) limit is 6.7 (3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let

    Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set

    Get PDF
    We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by PRL

    Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set

    Get PDF
    We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let

    The 2020 photovoltaic technologies roadmap

    Get PDF
    Over the past decade, the global cumulative installed photovoltaic (PV) capacity has grown exponentially, reaching 591 GW in 2019. Rapid progress was driven in large part by improvements in solar cell and module efficiencies, reduction in manufacturing costs and the realization of levelized costs of electricity that are now generally less than other energy sources and approaching similar costs with storage included. Given this success, it is a particularly fitting time to assess the state of the photovoltaics field and the technology milestones that must be achieved to maximize future impact and forward momentum. This roadmap outlines the critical areas of development in all of the major PV conversion technologies, advances needed to enable terawatt-scale PV installation, and cross-cutting topics on reliability, characterization, and applications. Each perspective provides a status update, summarizes the limiting immediate and long-term technical challenges and highlights breakthroughs that are needed to address them. In total, this roadmap is intended to guide researchers, funding agencies and industry in identifying the areas of development that will have the most impact on PV technology in the upcoming years

    Search for Higgs bosons of the minimal supersymmetric standard model in p-pbar collisions at sqrt(s)=1.96 TeV

    Get PDF
    We report results from searches for neutral Higgs bosons produced in p-pbar collisions recorded by the Dzero experiment at the Fermilab Tevatron Collider. We study the production of inclusive neutral Higgs boson in the tautau final state and in association with a b quark in the btautau and bbb final states. These results are combined to improve the sensitivity to the production of neutral Higgs bosons in the context of the minimal supersymmetric standard model (MSSM). The data are found to be consistent with expectation from background processes. Upper limits on MSSM Higgs boson production are set for Higgs boson masses ranging from 90 to 300 GeV. We exclude tanBeta>20-30 for Higgs boson masses below 180 GeV. These are the most stringent constraints on MSSM Higgs boson production in p-pbar collisions.Comment: Submitted to Phys. Lett.
    corecore