4,624 research outputs found

    The Effects of Two Modes of High-Intensity Intermittent Exercise on Postprandial Metabolism

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    The purpose of this study was to see if exercise in the form of Tabata or Sprinting would lower postprandial lipemia and glycemia. Tabata was composed of body-weight exercises. Both Tabata and Sprinting consisted of 5 rounds with each round lasting 4 minutes and included movements performed for 20 seconds followed by 10sec of rest. Following the completion of each round, participants received a 60 second break. Both exercise sessions were isocaloric and lasted 25min. Thirty minutes following exercise, participants were given a 75g-oral glucose solution and a high-fat meal two hours following exercise. The postprandial assessment lasted 6 hours. Results of the study showed no significant differences in the TG or glucose concentration compared to rest. There was a significant difference between the total area under the curve for glucose when comparing Tabata to Sprinting (p=.045). In conclusion, high-intensity interval exercise has no effect on postprandial lipemia or glycemia

    On Ptolemaic metric simplicial complexes

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    We show that under certain mild conditions, a metric simplicial complex which satisfies the Ptolemy inequality is a CAT(0) space. Ptolemy’s inequality is closely related to inversions of metric spaces. For a large class of metric simplicial complexes, we characterize those which are isometric to Euclidean space in terms of metric inversions

    Actual Versus Predicted VO2max: A Comparison of 4 Different Methods

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    ABSTRACT Measuring expired gases (EGs) while performing a maximal (max) effort exercise test is considered the most accurate evaluation of VO2 max. This methodology is not applicable for all populations. Submaximal (sub-max) protocols not measuring expired gases are more applicable, however their ability to accurately predict VO2max is not clear. PURPOSE: To compare VO2max results from 1) University of Houston Non-Exercise Test (UHNET), 2) McArdle Step Test (MST), 3) Bruce Protocol measuring EGs to max (Bruce-EGs), and 4) Bruce Protocol using time to max (Bruce-TM). METHODS: Recreationally active men and women {n= 24 (16M/8W); age = 25±7.7 years; body mass = 74.5±10.9kg; BMI = 24.3±2.9} completed 4 tests (on the same day) in the following order: 1) UHNET, 2) MST, 3) Bruce-EGs, and 4) Bruce-TM. For the UHNET, participants rated his/her physical activity (PAR). This was followed with a specified equation to estimate the participants VO2 max based on their PAR, age, BMI, and gender. Upon completion of the UHNET, participants performed the MST. The MST required participants to step on a 16.25inch bench at a specific cadence (different for men and women) for 3 minutes. Five seconds following the MST, radial pulse (RP) was assessed for 15 seconds. The radial pulse was converted to HR (beats/min) using the formula (RP*4). To estimate VO2max from the MST, the HR value was applied to a specific equation (different for men and women). Ten minutes after completing the MST, participants performed the Bruce protocol to max. For the Bruce Protocol, VO2max was calculated via 1) measurement of EGs and 2) the time it took to achieve max (TM). Expired gases were measured using a metabolic cart (Parvo Medics TrueOne 2400). To estimate VO2max using TM, the Bruce Protocol Time Formula (different for men and women) was applied. In addition to EGs and TM, HRmax, and Respiratory Exchange Ratio (RER) were assessed. Significant differences (p2 (Bruce-EGs) and estimated VO2 (UHNET, MST, and Bruce-TM) were determined using a one-way repeated measures ANOVA. Pearson correlations and liner regression were performed to determine the relationship between the estimated and actual VO2, as well as, determine how well the estimated VO2 predicted the actual VO2. RESULTS: For the Bruce protocol, HRmax=192±10.1bpm; RER=1.2±0.1, and TM=11.29±1.5 min. For the MST, the average HR was 144±23.3bpm. The actual VO2 (46.3±9.4 ml•kg-1•min -1) was similar to the estimated VO2 from UHNET (45.7±5.6 ml•kg-1•min-1) (p=.67) and MST (47.7±10.1 ml•kg-1•min-1) (p=.32). However, the VO2 obtained from the Bruce-TM (42.3±6.7 ml•kg-1•min-1) was significantly lower (p2 . Significant correlations (p2 and all predicted VO2 values. Liner regression equations expressed an R2 of .38, .61, and .65 for UHNET, MST, and Bruce-TM, respectively. CONCLUSION: Bruce-TM provided the most accurate estimation of the actual VO2max. The MST was slightly less predictive of VO2max though still a valid predictor. The results of this study suggest that to accurately predict VO2max, individuals will need to achieve max effort but might not need to have EGs analyzed. The MST results suggest that estimating VO2max on individuals who do not achieve max effort is still a valid option though might not be as accurate as when achieving max effort. These results should be taken with caution. This study was limited by 1) a small sample size, 2) evaluated only 2 modes of exercise, 3) a potential bias due to non-randomized trials, and 4) evaluated only healthy, active individuals. Increasing the sample size, comparing more methodologies, and randomizing the trials could strengthen the validity of any future investigations

    A global fit of top quark effective theory to data

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    In this paper we present a global fit of beyond the Standard Model (BSM) dimension six operators relevant to the top quark sector to currently available data. Experimental measurements include parton-level top-pair and single top production from the LHC and the Tevatron. Higher order QCD corrections are modelled using differential and global K-factors, and we use novel fast-fitting techniques developed in the context of Monte Carlo event generator tuning to perform the fit. This allows us to provide new, fully correlated and model-independent bounds on new physics effects in the top sector from the most current direct hadron-collider measurements in light of the involved theoretical and experimental systematics. As a by-product, our analysis constitutes a proof-of-principle that fast fitting of theory to data is possible in the top quark sector, and paves the way for a more detailed analysis including top quark decays, detector corrections and precision observables.Comment: Additional references and preprint code added. Minor error in generation of plots fixed, no conclusions affecte

    Adhesion, friction, and deformation of ion-beam-deposited boron nitride films

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    The tribological properties and mechanical strength of boron nitride films were investigated. The BN films were predominantly amorphous and nonstoichiometric and contained small amounts of oxides and carbides. It was found that the yield pressure at full plasticity, the critical load to fracture, and the shear strength of interfacial adhesive bonds (considered as adhesion) depended on the type of metallic substrate on which the BN was deposited. The harder the substrate, the greater the critical load and the adhesion. The yield pressures of the BN film were 12 GPa for the 440C stainless steel substrate, 4.1 GPa for the 304 stainless steel substrate, and 3.3 GPa for the titanium substrate

    Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander

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    Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial–interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change.This research was supported by the European Science Foundation (Frontiers of Speciation Research, Exchange grant 3318), and by the European Commission (Synthesys grant ES-TAF-1486), granted to RJP.During the preparation of this manuscript, RJP was funded by the European Union’s Horizon 2020 research and innovation programme, under the Marie Sklodowska-Curie grant agreement No 658706.Peer reviewe

    SALT Spectropolarimetry and Self-Consistent SED and Polarization Modeling of Blazars

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    We report on recent results from a target-of-opportunity program to obtain spectropolarimetry observations with the Southern African Large Telescope (SALT) on flaring gamma-ray blazars. SALT spectropolarimetry and contemporaneous multi-wavelength spectral energy distribution (SED) data are being modelled self-consistently with a leptonic single-zone model. Such modeling provides an accurate estimate of the degree of order of the magnetic field in the emission region and the thermal contributions (from the host galaxy and the accretion disk) to the SED, thus putting strong constraints on the physical parameters of the gamma-ray emitting region. For the specific case of the γ\gamma-ray blazar 4C+01.02, we demonstrate that the combined SED and spectropolarimetry modeling constrains the mass of the central black hole in this blazar to MBH109MM_{\rm BH} \sim 10^9 \, M_{\odot}.Comment: Submitted to Galaxies - Proceedings of "Polarized Emission from Astrophysical Jets", Ierapetra, Crete, June 12 - 16, 201
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