5,553 research outputs found

    Prospects for Higgs Search at D0

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    The status of the Higgs search at the upgraded D0 detector is discussed.Comment: Proceedings submitted for PASCOS03, Mumbai, India, Jan 3-8, 200

    Measurements of the Top Quark Mass at D0

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    We present measurements of the top quark mass based on 3.6 fb^-1 of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We present results in the dilepton and lepton+jets final states. We also present the measurement of the mass difference between t and tbar quarks observed in lepton+jets final states of ttbar events in 1 fb^-1 of data.Comment: Proceedings of the 17th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY09

    Predicting postoperative troponin in patients undergoing elective hip or knee arthroplasty: A comparison of five cardiac risk prediction tools

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    BACKGROUND: Elderly patients undergoing hip or knee arthroplasty are at a risk for myocardial injury after noncardiac surgery (MINS). We evaluated the ability of five common cardiac risk scores, alone or combined with baseline high-sensitivity cardiac troponin I (hs-cTnI), in predicting MINS and postoperative day 2 (POD2) hs-cTnI levels in patients undergoing elective total hip or knee arthroplasty. METHODS: This study is ancillary to the Genetics-InFormatics Trial (GIFT) of Warfarin Therapy to Prevent Deep Venous Thrombosis, which enrolled patients 65 years and older undergoing elective total hip or knee arthroplasty. The five cardiac risk scores evaluated were the atherosclerotic cardiovascular disease calculator (ASCVD), the Framingham risk score (FRS), the American College of Surgeon\u27s National Surgical Quality Improvement Program (ACS-NSQIP) calculator, the revised cardiac risk index (RCRI), and the reconstructed RCRI (R-RCRI). RESULTS: None of the scores predicted MINS in women. Among men, the ASCVD ( CONCLUSION: In elderly patients undergoing elective hip or knee arthroplasty, several of the scores modestly predicted MINS in men and correlated with POD2 hs-cTnI

    Vitamin D Supplementation and Immune Response to Antarctic Winter

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    Maintaining vitamin D status without sunlight exposure is difficult without supplementation. This study was designed to better understand interrelationships between periodic cholecalciferol(vitamin D3) supplementation and immune function in Antarctic workers. The effect of 2 oral dosing regimens of vitamin D3 supplementation on vitamin D status and markers of immune function were evaluated in people in Antarctica with no ultraviolet light exposure for 6 mo. Participants were given a 2,000-IU (50 g) daily (n=15) or 10,000-IU (250 g) weekly (n=14) vitamin D3 supplement for 6 mo during a winter in Antarctica. Biological samples were collected at baseline and at 3 and 6 mo. Vitamin D intake, markers of vitamin D and bone metabolism, and latent virus reactivation were determined. After 6 mo the mean (SD) serum 25-hydroxyvitamin D3 concentration increased from 56 plus or minus 17 to 79 plus or minus 16 nmol/L and 52 plus or minus 10 to 69 plus or minus 9 nmol/L in the 2,000-IU/d and 10,000-IU/wk groups (main effect over time P less than 0.001). Participants with a greater BMI (participant BMI range = 19-43 grams per square meter) had a smaller increase in 25-hydroxyvitamin D3 after 6 mo supplementation (P less than 0.05). Participants with high serum cortisoland higher serum 25-hydroxyvitamin D3 were less likely to shed Epstein-Barr virus in saliva (P less than 0.05). The doses given raised vitamin D status in participants not exposed to sunlight for 6 mo, and the efficacy was influenced by baseline vitamin D status and BMI. The data also provide evidence that vitamin D, interacting with stress, can reduce risk of latent virus reactivation during the winter in Antarctica

    Subfactors of index less than 5, part 1: the principal graph odometer

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    In this series of papers we show that there are exactly ten subfactors, other than AA_\infty subfactors, of index between 4 and 5. Previously this classification was known up to index 3+33+\sqrt{3}. In the first paper we give an analogue of Haagerup's initial classification of subfactors of index less than 3+33+\sqrt{3}, showing that any subfactor of index less than 5 must appear in one of a large list of families. These families will be considered separately in the three subsequent papers in this series.Comment: 36 pages (updated to reflect that the classification is now complete

    Reliability and Validity of Ultrasound Cross Sectional Area Measurements for Long-Duration Spaceflight

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    Limb muscle atrophy and the accompanying decline in function can adversely affect the performance of astronauts during mission-related activities and upon re-ambulation in a gravitational environment. Previous characterization of space flight-induced muscle atrophy has been performed using pre and post flight magnetic resonance imaging (MRI). In addition to being costly and time consuming, MRI is an impractical methodology for assessing in-flight changes in muscle size. Given the mobility of ultrasound (US) equipment, it may be more feasible to evaluate changes in muscle size using this technique. PURPOSE: To examine the reliability and validity of using a customized template to acquire panoramic ultrasound (US) images for determining quadriceps and gastrocnemius anatomical cross sectional area (CSA). METHODS: Vastus lateralis (VL), rectus femoris (RF), medial gastrocnemius (MG), and lateral gastrocnemius (LG) CSA were assessed in 10 healthy individuals (36+/-2 yrs) using US and MRI. Panoramic US images were acquired by 2 sonographers using a customized template placed on the thigh and calf and analyzed by the same 2 sonographers (CX50 Philips). MRI images of the leg were acquired while subjects were supine in a 1.5T scanner (Signa Horizon LX, General Electric) and were analyzed by 3 trained investigators. The average of the 2 US and 3 MRI values were used for validity analysis. RESULTS: High inter-experimenter reliability was found for both the US template and MRI analysis as coefficients of variation across muscles ranged from 2.4 to 4.1% and 2.8 to 3.8%, respectively. Significant correlations were found between US and MRI CSA measures (VL, r = 0.85; RF, r = 0.60; MG, r = 0.86; LG, r = 0.73; p < 0.05). Furthermore, the standard error of measurement between US and MRI ranged from 0.91 to 2.09 sq cm with high limits of agreement analyzed by Bland-Altman plots. However, there were significant differences between absolute values of MRI and US for all muscles. CONCLUSION: The present results indicate that utilizing a customized US template provides reliable measures of leg muscle CSA, and thus could be used to characterize changes in muscle CSA both in flight and on the ground

    Top Quark Physics at the Tevatron

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    The discovery of the top quark in 1995, by the CDF and D0 collaborations at the Fermilab Tevatron, marked the dawn of a new era in particle physics. Since then, enormous efforts have been made to study the properties of this remarkable particle, especially its mass and production cross section. In this article, we review the status of top quark physics as studied by the two collaborations using the p-pbar collider data at sqrt(s) = 1.8 TeV. The combined measurement of the top quark mass, m_t = 173.8 +- 5.0 GeV/c^2, makes it known to a fractional precision better than any other quark mass. The production cross sections are measured as sigma (t-tbar) = 7.6 -1.5 +1.8 pb by CDF and sigma (t-tbar) = 5.5 +- 1.8 pb by D0. Further investigations of t-tbar decays and future prospects are briefly discussed.Comment: 119 pages, 59 figures, 17 tables Submitted to Int. J. Mod. Phys. A Fixed some minor error

    Subfactors of index less than 5, part 3: quadruple points

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    One major obstacle in extending the classification of small index subfactors beyond 3+\sqrt{3} is the appearance of infinite families of candidate principal graphs with 4-valent vertices (in particular, the "weeds" Q and Q' from Part 1 (arXiv:1007.1730)). Thus instead of using triple point obstructions to eliminate candidate graphs, we need to develop new quadruple point obstructions. In this paper we prove two quadruple point obstructions. The first uses quadratic tangles techniques and eliminates the weed Q' immediately. The second uses connections, and when combined with an additional number theoretic argument it eliminates both weeds Q and Q'. Finally, we prove the uniqueness (up to taking duals) of the 3311 Goodman-de la Harpe-Jones subfactor using a combination of planar algebra techniques and connections.Comment: 21 page

    A10 – Human Factors Considerations of UAS Procedures and Control Stations: Tasks PC-1 through PC-3 Pilot and Crew (PC) Subtask, Recommended Requirements and Operational Procedures

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    The Alliance for System Safety of UAS through Research Excellence (ASSURE) conducted research focused on minimum pilot procedures and operational practices used by unmanned aircraft systems (UAS) operators today for the purpose of developing recommendations. This research recommends four pilot and 46 operational minimum procedures to operate a civil single-engine, fixed-wing, single-pilot-configured UAS flying in beyond visual line-of-sight (BVLOS) conditions. These recommendations are anticipated to support potential future aircrew procedure requirements for UAS larger than 55 lbs. operating in the National Airspace System (NAS). These procedures were validated using representative Control Stations in simulated environments
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