240 research outputs found

    Development and Validation of the Cognitive Behavioral Physical Activity Questionnaire

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    Purpose: Develop and demonstrate preliminary validation of a brief questionnaire aimed at assessing social cognitive determinants of physical activity (PA) in a college population. Design: Quantitative and observational. Setting: A midsized northeastern university. Subjects: Convenience sample of 827 male and female college students age 18 to 24 years. Measures: International Physical Activity Questionnaire and a PA stage-of-change algorithm. Analysis: A sequential process of survey development, including item generation and data reduction analyses by factor analysis, was followed with the goal of creating a parsimonious questionnaire. Structural equation modeling was used for confirmatory factor analysis and construct validation was confirmed against self-reported PA and stage of change. Validation analyses were replicated in a second, independent sample of 1032 college students. Results: Fifteen items reflecting PA self-regulation, outcome expectations, and personal barriers explained 65% of the questionnaire data and explained 28.6% and 39.5% of the variance in total PA and moderate-to-vigorous–intensity PA, respectively. Scale scores were distinguishable across the stages of change. Findings were similar when the Cognitive Behavioral Physical Activity Questionnaire (CBPAQ) was tested in a similar and independent sample of college students (40%; R2 moderate-to-vigorous–intensity PA = .40; p \u3c .001). Conclusion: The CBPAQ successfully explains and predicts PA behavior in a college population, warranting its incorporation into future studies aiming at understanding and improving on PA behavior in college students

    A Millisecond Interferometric Search for Fast Radio Bursts with the Very Large Array

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    We report on the first millisecond timescale radio interferometric search for the new class of transient known as fast radio bursts (FRBs). We used the Very Large Array (VLA) for a 166-hour, millisecond imaging campaign to detect and precisely localize an FRB. We observed at 1.4 GHz and produced visibilities with 5 ms time resolution over 256 MHz of bandwidth. Dedispersed images were searched for transients with dispersion measures from 0 to 3000 pc/cm3. No transients were detected in observations of high Galactic latitude fields taken from September 2013 though October 2014. Observations of a known pulsar show that images typically had a thermal-noise limited sensitivity of 120 mJy/beam (8 sigma; Stokes I) in 5 ms and could detect and localize transients over a wide field of view. Our nondetection limits the FRB rate to less than 7e4/sky/day (95% confidence) above a fluence limit of 1.2 Jy-ms. Assuming a Euclidean flux distribution, the VLA rate limit is inconsistent with the published rate of Thornton et al. We recalculate previously published rates with a homogeneous consideration of the effects of primary beam attenuation, dispersion, pulse width, and sky brightness. This revises the FRB rate downward and shows that the VLA observations had a roughly 60% chance of detecting a typical FRB and that a 95% confidence constraint would require roughly 500 hours of similar VLA observing. Our survey also limits the repetition rate of an FRB to 2 times less than any known repeating millisecond radio transient.Comment: Submitted to ApJ. 13 pages, 9 figure

    Association Between Anthropometrics, Vertical Jump and Broad Jump to Pure and Transitional Acceleration in Junior College Baseball Players

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    Sprint acceleration is a key physical attribute in baseball players that can be characterized by two phases: pure (PURE) and transitional (TRANS) acceleration. In a linear sprint, PURE occurs from the initiation of movement to approximately 15-meters; TRANS acceleration occurs from approximately 15-meters until an athlete reaches top velocity. Since baseball fields are clearly marked at 13.7m (foul-line) and 27.4m (1st base), acceleration can be determined in a sports-specific environment and these data may be helpful in characterizing player success. Purpose The purpose of this study was to determine the relationship between anthropometrics, vertical, and broad jump ability to PURE and TRANS acceleration of junior college baseball players sprinting to first-base. Methods: Nineteen male junior college baseball players (19.6 ± 2.2y; 181.2 ± 6.9cm; 80.6 ± 11.7kg) volunteered as subjects. They performed tests of physical performance on three days, separated by one week. Initially, subject height and body mass (BM) were determined using a standard equipment. Percent fat (%Fat) was measured using skinfold calipers and a three-site equation. On a separate day, countermovement vertical jumps were performed on a force plate set to sample at 400 Hz. Vertical jump height (VJ), peak force (PF), peak power (PP), and relative power (PP rel) were determined from these data. Broad jump (BJ) distance was measured using a marked court and tape measure. During a third testing day, subjects performed linear sprints from the batter’s box to first-base. Time was recorded at the foul-line and first-base using hand-held stop watches. Acceleration was computed between the two 13.7 meter intervals to first-base: home-plate to the foul-line (PURE) and foul-line to first-base (TRANS). Pearson’s r were calculated between PURE and TRANS and the anthropometric and performance data. Alpha was set a p \u3c 0.05 which equated to r = 0.44 for df = 18. Results: Of the tested variables, PURE was only associated with %Fat (r = -0.50), TRANS was significantly correlated with %Fat (r = -0.61), VJ (r = -0.50), and PP rel (r \=-0.51). Conclusion: These preliminary data indicate a primary determinant of pure acceleration to first-base is %Fat. VJ and PP relative to body mass are also associated with acceleration from the foul-line to first-base. Interesting, body mass was not related to acceleration in either phase. Therefore, strength and conditioning programs that reduce body fat and develop increased peak vertical power capabilities may be helpful in improving overall acceleration to first-base

    VLA/Realfast Detection of a Burst from FRB 180916.J0158+65 and Tests for Periodic Activity

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    We report on the detection of a burst from FRB 180916 by realfast/Very Large Array and present software for interpreting fast radio bursts (FRB) periodicity. We demonstrate a range of periodicity analyses with bursts from FRB 180916, FRB 121102 and FRB 180814. Our results for FRB 180916 and FRB 121102 are consistent with published results. For FRB 180814, we did not detect any significant periodic episodes. The realfast-detected and other high-frequency bursts for FRB 180916 tend to lie at the beginning of the activity window, indicating a possible phase-frequency relation. The python package frbpa can be used to reproduce and expand on this analysis to test models for repeating FRBs

    VLA/Realfast Detection of a Burst from FRB180916.J0158+65 and Tests for Periodic Activity

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    We report on the detection of a burst from FRB180916 by realfast/VLA and present software for interpreting fast radio bursts (FRB) periodicity. We demonstrate a range of periodicity analyses with bursts from FRB180916, FRB121102 and FRB180814. Our results for FRB180916 and FRB121102 are consistent with published results. For FRB180814, we did not detect any significant periodic episodes. The realfast-detected and other high-frequency bursts for FRB180916 tend to lie at the beginning of the activity window, indicating a possible phase-frequency relation. The python package frbpa\texttt{frbpa} can be used to reproduce and expand on this analysis to test models for repeating FRBs.Comment: Published in Research Notes of the AA

    Microbial community structure from southern High Plains beef cattle feedyard manure and relationship with nitrous oxide emissions

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    Modern molecular techniques enable characterization of the microbial biome in livestock manure, from which there is particular concern over emission of greenhouse gases. This study evaluated how sampling depth, time, temperature, and artificial rainfall affected microbial community structure in feedyard manure, and relationships between the manure biome and known parameters related to nitrous oxide (N2O) emissions. In three large incubation chambers, maintained at different temperatures that received two applications of artificial rainfall, we evaluated manure microbiome composition and abundance of N2O-producing enzymes (nirK and nirS) using quantitative polymerase chain reaction (qPCR). These data were used with previously published data from the same study on N2O emissions and assessment of manure physicochemical properties, denitrification enzyme activity (DEA), and nitrification activity (NA). Microbiome composition was Firmicutes (50%), followed by 32% Actinobacteria, 11% Proteobacteria, 5% Bacteroidetes, 1% Chloroflexi, and small populations (\u3c0.5%) of Planctomycetes, Deinococcus-Thermus, Gemmatimonadetes, Verrucomicrobia, Tenericutes, and other organisms. Average bacterial populations varied largely as a function of sampling depth and time. Firmicutes increases tended to coincide with high N2O emissions. Overall, the largest change observed was increased Proteobacteria at 5–10 cm, where relative abundance increased from 10% (17.2 °C) to 24% (46.2 °C) over time and with increased temperature. Firmicutes and Actinobacteria predominated the microbial community of manure, but favorable conditions may lead to increases in Bacteroidetes, Proteobacteria, and Chloroflexi, which could influence N cycling and N2O emissions from feedyards. Copy numbers of nirS at the beginning of the experiment were higher than nirK. Differences in concentrations of nirK and nirS indicated that denitrifying enzymes in feedyard manure, particularly nirS, were sensitive to environmental changes

    The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102

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    The precise localization of the repeating fast radio burst (FRB 121102) has provided the first unambiguous association (chance coincidence probability p≲3×10−4p\lesssim3\times10^{-4}) of an FRB with an optical and persistent radio counterpart. We report on optical imaging and spectroscopy of the counterpart and find that it is an extended (0.6′′−0.8′′0.6^{\prime\prime}-0.8^{\prime\prime}) object displaying prominent Balmer and [OIII] emission lines. Based on the spectrum and emission line ratios, we classify the counterpart as a low-metallicity, star-forming, mr′=25.1m_{r^\prime} = 25.1 AB mag dwarf galaxy at a redshift of z=0.19273(8)z=0.19273(8), corresponding to a luminosity distance of 972 Mpc. From the angular size, the redshift, and luminosity, we estimate the host galaxy to have a diameter ≲4\lesssim4 kpc and a stellar mass of M∗∼4−7×107 M⊙M_*\sim4-7\times 10^{7}\,M_\odot, assuming a mass-to-light ratio between 2 to 3 M⊙ L⊙−1\,M_\odot\,L_\odot^{-1}. Based on the Hα\alpha flux, we estimate the star formation rate of the host to be 0.4 M⊙ yr−10.4\,M_\odot\,\mathrm{yr^{-1}} and a substantial host dispersion measure depth ≲324 pc cm−3\lesssim 324\,\mathrm{pc\,cm^{-3}}. The net dispersion measure contribution of the host galaxy to FRB 121102 is likely to be lower than this value depending on geometrical factors. We show that the persistent radio source at FRB 121102's location reported by Marcote et al (2017) is offset from the galaxy's center of light by ∼\sim200 mas and the host galaxy does not show optical signatures for AGN activity. If FRB 121102 is typical of the wider FRB population and if future interferometric localizations preferentially find them in dwarf galaxies with low metallicities and prominent emission lines, they would share such a preference with long gamma ray bursts and superluminous supernovae.Comment: 12 pages, 3 figures, Published in ApJ Letters. V2: Corrected mistake in author lis

    High-Throughput Label-Free Isolation of Heterogeneous Circulating Tumor Cells and CTC Clusters from Non-Small-Cell Lung Cancer Patients.

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    (1) Background: Circulating tumor cell (CTC) clusters are emerging as clinically significant harbingers of metastases in solid organ cancers. Prior to engaging these CTC clusters in animal models of metastases, it is imperative for technology to identify them with high sensitivity. These clusters often present heterogeneous surface markers and current methods for isolation of clusters may fall short. (2) Methods: We applied an inertial microfluidic Labyrinth device for high-throughput, biomarker-independent, size-based isolation of CTCs/CTC clusters from patients with metastatic non-small-cell lung cancer (NSCLC). (3) Results: Using Labyrinth, CTCs (PanCK+/DAPI+/CD45-) were isolated from patients (n = 25). Heterogeneous CTC populations, including CTCs expressing epithelial (EpCAM), mesenchymal (Vimentin) or both markers were detected. CTCs were isolated from 100% of patients (417 +/- 1023 CTCs/mL). EpCAM- CTCs were significantly greater than EpCAM+ CTCs. Cell clusters of \u3e/=2 CTCs were observed in 96% of patients-of which, 75% were EpCAM-. CTCs revealed identical genetic aberrations as the primary tumor for RET, ROS1, and ALK genes using fluorescence in situ hybridization (FISH) analysis. (4) Conclusions: The Labyrinth device recovered heterogeneous CTCs in 100% and CTC clusters in 96% of patients with metastatic NSCLC. The majority of recovered CTCs/clusters were EpCAM-, suggesting that these would have been missed using traditional antibody-based capture methods
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