1,599 research outputs found

    A BIOMECHANICAL AND PHYSIOLOGICAL ANALYSIS OF EFFICIENCY AT DIFFERENT RUNNING PACES

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    The purpose of this study was to investigate the differences between several biomechanical and physiological variables associated with two different paces in treadmill running. The treadmill speed was adjusted to simulate an easy warm-up pace and a race pace for a 5000 m run. Another purpose was to study the contribution of both biomechanical and physiological variables toward total efficiency. The biomechanical variables included: (a) stride frequency, (b) stride length, (c) time of stride, and (d) percent of support. The physiological variables included: (a) heart rate, (b) R value, (c) V02, (d) percent of V02max, and (e) blood lactate. Nine intercollegiate distance runners from the north Texas area were filmed twice (5 min and 15 min) .from a sagittal view with a 16 mm high speed camera operating at 100 fps during two running paces. Joint segment markers were attached to the runners and one complete stride was digitized. The X/Y coordinates were used to determine the work per stride. Since physiological data were being collected simultaneously during the treadmill protocol, these were matched to the 5 min and 15 min film data intervals to determine total efficiency. A one-way repeated measures ANOVA was utilized with two paces and two times to investigate the biomechanical, physiological, and efficiency variables. Maximum experimentwise error control for Type I errors was necessary since ten dependent variables were utilized and the correlation matrix indicated that the data were nonorthogonal. A Bonferroni inequality test was also used and produced a modified alpha level of .005. No significant interactions for time by pace were found for any of the dependent variables. However, a trend does exist for several of the variables

    Rapid Evolution of BRCA1 and BRCA2 in Humans and Other Primates

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    The maintenance of chromosomal integrity is an essential task of every living organism and cellular repair mechanisms exist to guard against insults to DNA. Given the importance of this process, it is expected that DNA repair proteins would be evolutionarily conserved, exhibiting very minimal sequence change over time. However, BRCA1, an essential gene involved in DNA repair, has been reported to be evolving rapidly despite the fact that many protein-altering mutations within this gene convey a significantly elevated risk for breast and ovarian cancers. Results: To obtain a deeper understanding of the evolutionary trajectory of BRCA1, we analyzed complete BRCA1 gene sequences from 23 primate species. We show that specific amino acid sites have experienced repeated selection for amino acid replacement over primate evolution. This selection has been focused specifically on humans and our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). After examining BRCA1 polymorphisms in 7 bonobo, 44 chimpanzee, and 44 rhesus macaque (Macaca mulatta) individuals, we find considerable variation within each of these species and evidence for recent selection in chimpanzee populations. Finally, we also sequenced and analyzed BRCA2 from 24 primate species and find that this gene has also evolved under positive selection. Conclusions: While mutations leading to truncated forms of BRCA1 are clearly linked to cancer phenotypes in humans, there is also an underlying selective pressure in favor of amino acid-altering substitutions in this gene. A hypothesis where viruses are the drivers of this natural selection is discussed.National Institutes of Health R01-GM-093086, 8U42OD011197-13National Science Foundation BCS-07115972Burroughs Wellcome FundMolecular Bioscience

    A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment

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    The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200 meV/c^2 (90% C.L.) by a precision measurement of the shape of the tritium ÎČ\beta-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software "Kassiopeia", which was developed in the KATRIN collaboration over recent years.Comment: 19 pages, 16 figures, submitted to European Physical Journal

    emiT: an apparatus to test time reversal invariance in polarized neutron decay

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    We describe an apparatus used to measure the triple-correlation term (\D \hat{\sigma}_n\cdot p_e\times p_\nu) in the beta-decay of polarized neutrons. The \D-coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction beta-decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the proton detectors, beta detectors and the electronics used in the data collection system are presented. The neutron beam characteristics, the spin-transport magnetic fields, and polarization measurements are also described.Comment: 15 pages, 13 figure

    Lessons Learned From all For them: Best Practices For a Cross-Collaboration approach to Hpv Vaccination in Public Schools

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    The Community Preventive Services Task Force endorses vaccination programs in schools to increase access to vaccinations. However, implementing a school-based approach requires substantial coordination, planning, and resources. All for Them (AFT) is a multilevel, multicomponent approach to increase HPV vaccination among adolescents attending public schools in medically underserved areas in Texas. AFT comprised a social marketing campaign, school-based vaccination clinics, and school nurse continuing education. Process evaluation metrics and key informant interviews to understand experiences with AFT program implementation informed lessons learned. Lessons emerged in six domains: strong champion, school-level support, tailored and cost-effective marketing approaches, mobile provider collaboration, community presence, and crisis management. Strong support at district and school levels is vital for gaining principal and school nurse buy-in. Social marketing strategies are integral to program implementation and should be adjusted to maximize their effectiveness in motivating parents to vaccinate children against HPV, which also can be achieved through increased community presence of the project team. Preparing contingency plans and flexibility within the program can facilitate appropriate responses to provider restrictions in mobile clinics or in the event of unforeseen crises. These important lessons can offer useful guidelines for the development of prospective school-based vaccination programs

    Observed Coupling of the Mesosphere Inversion Layer to the Thermal Tidal Structure

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    Rayleigh lidar observations of mesosphere temperature profiles obtained from 40 to ∌100 km from Logan, Utah (41.7, 111.8 W, altitude, 1.9 km) over 10 nights in late February, 1995, revealed an interesting development between 60 to 75 km of a winter mesosphere inversion layer with an amplitude of ∌20–30 K and a downward phase progression of ∌1 km/hr. The data also showed two altitude regions exhibiting significant cooling of 10–30 K in extent. These were located below and above the peak of the inversion layer, respectively, at altitudes of ∌50–55 km and ∌70–80 km. When these results were compared with the predictions of a global wave scale model (GSWM), the observed thermal mesosphere structure is similar to the computed composite tidal structure based upon the semi‐diurnal and diurnal tides with the exception that observed amplitudes of heating and cooling are ∌10x larger than predicted GSWM values. We suggest that these events over Utah are caused through a localized mechanism involving the coupling of gravity waves to the mesopause tidal structure

    Integrative analyses identify modulators of response to neoadjuvant aromatase inhibitors in patients with early breast cancer

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    Introduction Aromatase inhibitors (AIs) are a vital component of estrogen receptor positive (ER+) breast cancer treatment. De novo and acquired resistance, however, is common. The aims of this study were to relate patterns of copy number aberrations to molecular and proliferative response to AIs, to study differences in the patterns of copy number aberrations between breast cancer samples pre- and post-AI neoadjuvant therapy, and to identify putative biomarkers for resistance to neoadjuvant AI therapy using an integrative analysis approach. Methods Samples from 84 patients derived from two neoadjuvant AI therapy trials were subjected to copy number profiling by microarray-based comparative genomic hybridisation (aCGH, n = 84), gene expression profiling (n = 47), matched pre- and post-AI aCGH (n = 19 pairs) and Ki67-based AI-response analysis (n = 39). Results Integrative analysis of these datasets identified a set of nine genes that, when amplified, were associated with a poor response to AIs, and were significantly overexpressed when amplified, including CHKA, LRP5 and SAPS3. Functional validation in vitro, using cell lines with and without amplification of these genes (SUM44, MDA-MB134-VI, T47D and MCF7) and a model of acquired AI-resistance (MCF7-LTED) identified CHKA as a gene that when amplified modulates estrogen receptor (ER)-driven proliferation, ER/estrogen response element (ERE) transactivation, expression of ER-regulated genes and phosphorylation of V-AKT murine thymoma viral oncogene homolog 1 (AKT1). Conclusions These data provide a rationale for investigation of the role of CHKA in further models of de novo and acquired resistance to AIs, and provide proof of concept that integrative genomic analyses can identify biologically relevant modulators of AI response

    Multi-layer scintillation detector for the MOON double beta decay experiment: Scintillation photon responses studied by a prototype detector MOON-1

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    An ensemble of multi-layer scintillators is discussed as an option of the high-sensitivity detector Mo Observatory Of Neutrinos (MOON) for spectroscopic measurements of neutrino-less double beta decays. A prototype detector MOON-1, which consists of 6 layer plastic-scintillator plates, was built to study the sensitivity of the MOON-type detector. The scintillation photon collection and the energy resolution, which are key elements for the high-sensitivity experiments, are found to be 1835+/-30 photo-electrons for 976 keV electrons and sigma = 2.9+/-0.1% (dE/E = 6.8+/-0.3 % in FWHM) at the Qbb ~ 3 MeV region, respectively. The multi-layer plastic-scintillator structure with good energy resolution as well as good background suppression of beta-gamma rays is crucial for the MOON-type detector to achieve the inverted hierarchy neutrino mass sensitivity.Comment: 8 pages, 16 figures, submitted to Nucl.Instrum.Met

    Searches for neutrinoless double beta decay

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    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136^{136}Xe. The sensitivities of the different proposals are reviewed.Comment: 8 pages, prepared for TAUP 201
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