3,444 research outputs found

    Bose-Einstein condensation in quasi-2D systems: applications to high Tc superconductivity

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    We describe high-Tc superconductivity in layered materials within a BCS theory as a BEC of massless-like Cooper pairons satisfying a linear dispersion relation, and propagating within quasi-2D layers of finite width defined by the charge distribution about the CuO_2 planes. We obtain a closed formula for the critical temperature, Tc, that depends on the layer width, the binding energy of Cooper's pairs, and the average in-plane penetration depth. This formula reasonably reproduces empirical values of superconducting transition temperatures for several different cuprate materials near the optimal doping regime, as well as for YBCO films with different doping degrees.Comment: 5 pages, 1 figur

    The impact of maternal BMI, gestational weight gain, and breastfeeding on early childhood weight: Analysis of a statewide WIC dataset

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    Early childhood obesity is a persistent health concern with more frequent and significant impact on low-income families. Maternal weight factors impact offspring weight status, but evidence on whether breastfeeding protects against this impact is mixed. This analysis examined a model to predict early childhood obesity risk, simultaneously accounting for maternal pre-pregnancy body mass index (BMI), gestational weight gain, and breastfeeding. The team analyzed 27,016 unique maternal-child dyadic records collected via the Supplemental Nutrition Program for Wisconsin Women, Infants, and Children (WIC) between 2009 and 2011. Generalized Linear Modeling, specifically logistic regression, was used to predict a child\u27s risk of obesity given the mother\u27s pre-pregnancy BMI, gestational weight gain, and duration of breastfeeding. For each 1 kg/m2 increase in pre-pregnancy BMI, there was a 4.5% increase in risk of obesity compared to children with mothers of normal BMI. Children whose mothers had excessive gestational weight gain were 50% more likely to have obesity compared to those whose mothers had ideal weight gain. For each week of additional breastfeeding, there was a 1.9% increased risk of obesity. The risk models did not differ by race. In this model, accounting for pre-pregnancy weight, gestational weight gain, and breastfeeding among a diverse, low-income sample, women with pre-pregnancy overweight and obesity or who had excessive gestational weight gain had the highest risk of early childhood obesity. While breastfeeding is healthy for many reasons, providers should focus on maternal weight-related behaviors when counseling mothers about how to avoid risk of early childhood obesity

    Mediating Effects of Positive Thinking and Social Support on Suicide Resilience

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    Suicide has been the second leading cause of death for 18- to 24-year-olds in the United States since 2011. The stress experienced by undergraduate college students has the potential to increase one’s risk for suicide. Resilience theory was used as a theoretical framework to examine the interplay between risk and protective factors. A cross-sectional and correlational design was used to assess the mediating effects of positive thinking and/or social support on suicide resilience in 131 college students 18 to 24 years old who completed an online survey. The study found an indirect effect of self-esteem on suicide resilience through positive thinking and social support indicating that as self-esteem increases, positive thinking and social support also increase, which leads to an increase in resilience. The study also found a direct effect of self-esteem, positive thinking, and social support on suicide resilience. The findings inform the development of tailored interventions to build suicide resilience in college students

    In Search of the Community University Student

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    Around the first week of school, a young man stayed after class to speak to me, waiting until everyone left. Sam was in his late twenties, early thirties, a serious student in class with a permanent frown as he listened intently. He was worried about comments I had made concerning attendance and he explained that there might be times during the semester when he would have to be absent if his children were sick. He softly added that he was a single father of four small children. Several days later, I had the opportunity to ask him about his family and, as a proud father, he showed me pictures of his children
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