818 research outputs found

    A Study of the 7-Li(p,n) 7-Be Excitation Function at Intermediate Energies Using Residual Activity

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    Supported by the National Science Foundation and Indiana Universit

    A Study of the 7-Li(p,n)7-Be Excitation Function at Intermediate Energies Using Residual Activity

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    This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

    Understanding the role of fathers in children's physical activity: A qualitative study

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    Background: Parents are influential in supporting children's physical activity, but relatively little is known about the role of fathers in children's physical activity. Methods: Semi-structured interviews (n = 24) were conducted with low-active and active fathers of children 3-11 years old. Deductive thematic analysis was used to identify fathers' physical activity practices and understand how fathers interact with their children around physical activity. Results: All fathers demonstrated coparticipation in physical activity with their children. Other physical activity practices commonly used by fathers included as follows: facilitation of active opportunities, modeling, involvement through coaching or teaching, and encouragement. In addition, fathers viewed physical activity as an opportunity to spend time with their children to bond and develop shared interests. Finally, fathers perceived their role in children's physical activity to be different compared with mothers. Regarding father activity level, active fathers discussed modeling more frequently and tended to engage in a variety of different activities compared with low-active fathers. Conclusions: Fathers play an important role in their children's physical activity, suggesting that physical activity may be one context in which to prompt paternal involvement, foster father-child relationships, and strengthen paternal parenting

    Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon

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    Results of observations of low energy nuclear and electron recoil events in liquid xenon scintillator detectors are given. The relative scintillation efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40 keV - 70 keV. Under the assumption of a single dominant decay component to the scintillation pulse-shape the log-normal mean parameter T0 of the maximum likelihood estimator of the decay time constant for 6 keV < Eee < 30 keV nuclear recoil events is equal to 21.0 ns +/- 0.5 ns. It is observed that for electron recoils T0 rises slowly with energy, having a value ~ 30 ns at Eee ~ 15 keV. Electron and nuclear recoil pulse-shapes are found to be well fitted by single exponential functions although some evidence is found for a double exponential form for the nuclear recoil pulse-shape.Comment: 11 pages, including 5 encapsulated postscript figure

    Comparative effectiveness of a standard behavioral and physical activity enhanced behavioral weight loss intervention in Black women

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    Black women typically lose small amounts of weight in behavioral weight loss interventions, partially due to low engagement in physical activity. Culturally relevant enhancement of the physical activity component may improve weight loss. This study compared the effectiveness of a culturally-relevant, physical activity-enhanced behavioral weight loss intervention to a standard behavioral weight loss intervention in Black women (n = 85) over 6 months. The study was conducted in two cohorts from March 2016 to February 2017 at the University of North Carolina at Chapel Hill. Participants had an average age of 48.30 ± 11.02 years with an average body mass index of 36.46 ± 4.50 kg/m2. Standard and enhanced groups’ weight change (−2.83 kg and −2.08 kg, respectively) and change in physical activity (43.93 min/ week and 15.29 min/week, respectively) did not differ between groups. Significantly more standard group participants lost 5% of baseline weight compared to enhanced group participants. This study produced typical weight loss results in Black women. Behavioral weight loss treatment remains moderately effective for Black women. Strategies to increase attendance and self-monitoring, and the inclusion of cultural contexts to weight-related behaviors are needed to improve outcomes

    Recent developments in planet migration theory

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    Planetary migration is the process by which a forming planet undergoes a drift of its semi-major axis caused by the tidal interaction with its parent protoplanetary disc. One of the key quantities to assess the migration of embedded planets is the tidal torque between the disc and planet, which has two components: the Lindblad torque and the corotation torque. We review the latest results on both torque components for planets on circular orbits, with a special emphasis on the various processes that give rise to additional, large components of the corotation torque, and those contributing to the saturation of this torque. These additional components of the corotation torque could help address the shortcomings that have recently been exposed by models of planet population syntheses. We also review recent results concerning the migration of giant planets that carve gaps in the disc (type II migration) and the migration of sub-giant planets that open partial gaps in massive discs (type III migration).Comment: 52 pages, 18 figures. Review article to be published in "Tidal effects in Astronomy and Astrophysics", Lecture Notes in Physic

    Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons

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    Using data collected with the BESII detector at e+e−e^{+}e^{-} storage ring Beijing Electron Positron Collider, the measurements of relative branching fractions for seven Cabibbo suppressed hadronic weak decays D0→K−K+D^0 \to K^- K^+, π+π−\pi^+ \pi^-, K−K+π+π−K^- K^+ \pi^+ \pi^- and π+π+π−π−\pi^+ \pi^+ \pi^- \pi^-, D+→K0ˉK+D^+ \to \bar{K^0} K^+, K−K+π+K^- K^+ \pi^+ and π−π+π+\pi^- \pi^+ \pi^+ are presented.Comment: 11 pages, 5 figure

    Renormalization and Chiral Symmetry Breaking in Quenched QED in Arbitrary Covariant Gauge

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    We extend a previous Landau-gauge study of subtractive renormalization of the fermion propagator Dyson-Schwinger equation (DSE) in strong-coupling, quenched QED_4 to arbitrary covariant gauges. We use the fermion-photon proper vertex proposed by Curtis and Pennington with an additional correction term included to compensate for the small gauge-dependence induced by the ultraviolet regulator. We discuss the chiral limit and the onset of dynamical chiral symmetry breaking in the presence of nonperturbative renormalization. We extract the critical coupling in several different gauges and find evidence of a small residual gauge-dependence in this quantity.Comment: REVTEX 3.0, 27 pages including 14 Extended Postscript files comprising 9 figures. Replacement: discussion of chiral limit corrected, and some minor typographical errors fixed. To appear in Phys. Rev.

    Development of a physiological model of human middle ear epithelium

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    Introduction Otitis media is an umbrella term for middle ear inflammation; ranging from acute infection to chronic mucosal disease. It is a leading cause of antimicrobial therapy prescriptions and surgery in children. Despite this, treatments have changed little in over 50 years. Research has been limited by the lack of physiological models of middle ear epithelium. Methods We develop a novel human middle ear epithelial culture using an air-liquid interface (ALI) system; akin to the healthy ventilated middle ear in vivo. We validate this using immunohistochemistry, immunofluorescence, scanning and transmission electron microscopy, and membrane conductance studies. We also utilize this model to perform a pilot challenge of middle ear epithelial cells with SARS-CoV-2. Results We demonstrate that human middle ear epithelial cells cultured at an ALI undergo mucociliary differentiation to produce diverse epithelial subtypes including basal (p63+), goblet (MUC5AC+, MUC5B+), and ciliated (FOXJ1+) cells. Mature ciliagenesis is visualized and tight junction formation is shown with electron microscopy, and confirmed by membrane conductance. Together, these demonstrate this model reflects the complex epithelial cell types which exist in vivo. Following SARS-CoV-2 challenge, human middle ear epithelium shows positive viral uptake, as measured by polymerase chain reaction and immunohistochemistry. Conclusion We describe a novel physiological system to study the human middle ear. This can be utilized for translational research into middle ear diseases. We also demonstrate, for the first time under controlled conditions, that human middle ear epithelium is susceptible to SARS-CoV-2 infection, which has important clinical implications for safe otological surgery. Level of Evidence NA
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