5,038 research outputs found

    Physical activity mediates the relationship between perceived crime safety and obesity

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    pre-printObjective. The current cross-sectional study tests whether low perceived crime safety is associated with body mass index (BMI) and obesity risk and whether less moderate-to-vigorous physical activity (MVPA) accounts for part of this relationship. Method. Adults (n=864) from a relatively low-income and ethnically mixed neighborhood in Salt Lake City UT (2012) were assessed for perceived crime safety, objective physical activity, and BMI measures. Results. This neighborhood had lower perceived safety than for other published studies utilizing this safety measure. In a mediation test, lower perceived crime safety was significantly associated with higher BMI and greater risk of obesity, net of control variables. Residents with lower perceived safety had less MVPA. Lower MVPA partially explained the relationship between less safety and both elevated BMI and higher obesity risk, suggesting that perceiving less crime safety limits MVPA which, in turn, increases weight. Conclusion. In this neighborhood, with relatively low perceived safety from crime, residents' low perceived safety related to more obesity and higher BMI; lower MVPA among residents explained part of this relationship. If residents are to become more active in their neighborhood it may be important to address perceived crime safety as part of broader efforts to enhance active living

    Preparing University Adjunct Faculty to Teach

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    Colleges and universities employ adjunct faculty to fill personnel needs not met when availability of full time faculty is insufficient; as such, academic leaders should find ways to ensure the success of this vitally important faculty group. This qualitative research inquiry studied adjunct faculty perceptions regarding factors deemed necessary to acquire and hone pedagogical competence in university settings. Using a phenomenological approach, the research team studied how eight college and university adjunct faculty, both pre-service and in-service, perceived teaching preparation. Deliberate Practice Theory undergirded this inquiry. Three themes emerged from the study: preparation to teach, teaching content, and institutional support. The research team recommends the following practices to prepare adjunct faculty for teaching success: construct job embedded professional development, foster a robust system of observation and feedback, and create adjunct faculty mentoring programs. Citation: Parker, D. M., McAuley Brown, L.T., Holmes, B.D. (2018). Preparing University Adjunct Faculty to Teach. Journal of Higher Education Theory and Practice 18(7).https://openriver.winona.edu/educationeddfacultyworks/1008/thumbnail.jp

    Discovery of an ultramassive pulsating white dwarf

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    We announce the discovery of the most massive pulsating hydrogen-atmosphere (DA) white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 +/- 210 K WD with a log(g) = 9.08 +/- 0.06, which corresponds to a mass of 1.20 +/- 0.03 Msun. Stellar evolution models indicate that the progenitor of such a high-mass WD endured a stable carbon-burning phase, producing an oxygen-neon-core WD. The discovery of pulsations in GD 518 thus offers the first opportunity to probe the interior of a WD with a possible oxygen-neon core. Such a massive WD should also be significantly crystallized at this temperature. The star exhibits multi-periodic luminosity variations at timescales ranging from roughly 425-595 s and amplitudes up to 0.7%, consistent in period and amplitude with the observed variability of typical ZZ Ceti stars, which exhibit non-radial g-mode pulsations driven by a hydrogen partial ionization zone. Successfully unraveling both the total mass and core composition of GD 518 provides a unique opportunity to investigate intermediate-mass stellar evolution, and can possibly place an upper limit to the mass of a carbon-oxygen-core WD, which in turn constrains SNe Ia progenitor systems.Comment: 5 pages, 3 figures, Astrophysical Journal Letters, 771, L2 (2013

    Maternal plasma DHA levels increase prior to 29 days post-LH surge in women undergoing frozen embryo transfer: a prospective, observational study of human pregnancy

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    Context: Docosahexaenoic acid (DHA) is an important fatty acid required for neurological development but its importance during early fetal neurological organogenesis is unknown. Objective: To assess plasma fatty acid changes in early pregnancy in women undergoing natural cycle-frozen embryo transfer as a means of achieving accurately-timed periconceptual sampling. Design: Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinising hormone (LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography. Setting: Assisted Conception Unit, Glasgow Royal Infirmary, Scotland Main outcome measures: Plasma fatty acid concentrations, influence of twin pregnancies on DHA plasma concentration. Results: In pregnant women, there was a rapid, early increase in the maternal rate of change of plasma DHA concentration observed by 29 days post-LH surge (mean±SD, from 0.1±1.3 to 1.6±2.9 nmol DHA per mL plasma per day). This early pressure to increase plasma DHA concentration was further emphasised in twin pregnancies where the increase in DHA concentration over 45 days was two-fold higher than in singleton pregnancies (mean±SD increase, 74±39 nmol/mL versus 36±40 nmol/mL). An index of delta-6 desaturase activity increased 30% and positively correlated with the rate of change of DHA concentration between day 18 and 29-post LH surge (R-squared adjusted = 41%, P=0.0002). DHA was the only fatty acid with a continual accelerated increase in plasma concentration and a positive incremental area under the curve (mean±SD, 632±911 nmol/mL x day) over the first 45 days of gestation. Conclusions: An increase in maternal plasma DHA concentration is initiated in human pregnancy prior to neural tube closure which occurs at 28 days' gestation

    Effect of Essential Fatty Acid Deficiency on Cutaneous Sterol Synthesis

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    The fact that the skin is a major site of total body sterologensis, coupled both with the apparent absence of low density lipoprotein receptors on keratinocytes and with the lack of influence of serum cholesterol on epidermal sterologensis, has created the impression that epidermal lipid synthesis might be autonomous, i.e. nonregulatable. Recent studies have shown, however, that disruption of cutaneous barrier function with acetone or detergents stimulates epidermal sterologensis (J Lipid Res 26:418–427, 1985). To correlate further sterologenesis with barrier function, we measured de novo synthesis of cholesterol and total nonsaponifiable lipids in essential fatty acid-deficient (EFAD) hairless mice. Animals with defective barrier function, manifested by abnormal transepidermal water loss, demonstrated a 2-fold increase in epidermal cholesterol and total nonsaponifiable lipid synthesis over controls while synthesis in the dermis was unchanged. Epidermal sterologenesis in EFAd animals, repleted with linoleic acid either systematically or topically, returned toward normal as barrier function improved. Moreover, plastic occlusion of EFAD mouse skin normalized epidermal sterologensis at 1 and 3 days. These results provide further evidence that epidermal sterologenesis is not entirely autonomous, and can be regulated by water barrier requirements

    Decreased Epidermal Lipid Synthesis Accounts for Altered Barrier Function in Aged Mice

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    The epidermis of aged mice displays decreased stratum corneum (SC) lipid content and decreased extracellular bilayers, which result in impaired barrier recovery following the solvent treatment or tape stripping. We assessed the role of altered lipid synthesis as the cause of the abnormal barrier and lipid content in aged epidermis, both under basal conditions and in response to acute barrier perturbations. In aged epidermis (≥18months), synthesis of one of the three key lipid classes (cholesterol) is decreased under basal conditions, and sterologenesis fails to attain the levels reached in young epidermis following comparable acute perturbations. In contrast, fatty acid and sphingolipid synthesis in aged epidermis increase sufficiently to approach the levels attained in stimulated young epidermis. The abnormalities in sterologenesis in aged epidermis are paralleled by a decrease in activity of its rate-limiting enzyme, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, under basal conditions, and enzyme activity also fails to increase as much as in young epidermis after barrier disruption. That defective lipid generation contributes to the barrier defect is shown directly by the ability of either a cholesterol-containing mixture of SC lipids or cholesterol alone to enhance barrier recovery. Finally, lipid-induced acceleration of barrier recovery in aged epidermis correlates with repletion of the extracellular spaces with normal lamellar structures. Thus, a deficiency in lipid synthesis, particularly in cholesterologenesis, accounts for the barrier abnormality in aged epidermis

    The Lovastatin-Treated Rodent: A New Model of Barrier Disruption and Epidermal Hyperplasia

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    Recent studies have linked epidermal cholesterol synthesis with maintenance of the permeability barrier. To assess directly the importance of cholesterol synthesis, we applied lovastatin, a potent inhibitor of cholesterol synthesis, to hairless mouse skin. Transepidermal water loss (TEWL) began to increase after four to six daily applications. Co-application of cholesterol blocked the expected increase in TEWL, demonstrating the importance of cholesterol for development of the lesion. The histology of lovastatin-treated skin revealed epidermal hyperplasia, accompanied by accelerated DNA synthesis. Whereas cholesterol synthesis initially was reduced in lovastatin-treated epidermis, with further treatment cholesterol synthesis normalized, while fatty acid synthesis accelerated greatly. Although the total free sterol content of lovastatin-treated epidermis remained normal, the fatty acid content increased coincident with barrier disruption. Finally, morphologic abnormalities of both lamellar body structure and their deposited, intercellular contents occurred coincident with the emerging biochemical abnormalities. Thus, the abnormal barrier function in this model can be ascribed to an initial inhibition of epidermal sterol synthesis followed by an alteration in cholesterol and fatty acid synthesis, leading to an imbalance in stratum corneum lipid composition and abnormal membrane bilayer structure
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