863 research outputs found

    Orion Aerodynamics for Hypersonic Free Molecular to Continuum Conditions

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    Numerical simulations are performed for the Orion Crew Module, previously known as the Crew Exploration Vehicle (CEV) Command Module, to characterize its aerodynamics during the high altitude portion of its reentry into the Earth's atmosphere, that is, from free molecular to continuum hypersonic conditions. The focus is on flow conditions similar to those that the Orion Crew Module would experience during a return from the International Space Station. The bulk of the calculations are performed with two direct simulation Monte Carlo (DSMC) codes, and these data are anchored with results from both free molecular and Navier-Stokes calculations. Results for aerodynamic forces and moments are presented that demonstrate their sensitivity to rarefaction, that is, for free molecular to continuum conditions (Knudsen numbers of 111 to 0.0003). Also included are aerodynamic data as a function of angle of attack for different levels of rarefaction and results that demonstrate the aerodynamic sensitivity of the Orion CM to a range of reentry velocities (7.6 to 15 km/s)

    Professional Writing in the English Classroom: Student Writers as Problem Solvers in Literature Classrooms

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    The article reports on the role of student writers in the U.S. to enhance the study of literature in the classroom. High school teacher Dawn Reed shares how students\u27 professional writing served as a starting point for deeper study and advocacy of American literature. It provides an overview of Katie Greene\u27s assessment system that creates flexibility while providing a model of evaluation which can be adapted for other professional writing experiences

    The retirement experiences of elite female gymnasts: Self identity and the physical self

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    This study explored experiences of retirement from elite sport among a sample of retired female gymnasts. Given the young age at which female gymnasts begin and end their sport careers, particular attention was afforded to the role of identity and the physical self in the process of adaptation. Retrospective, semi-structured interviews were conducted and interview transcripts analyzed using interpretative phenomenological analysis. Analysis indicated that retirement from gymnastics engendered adjustment difficulties for six of the seven participants. Identity loss was particularly salient, and for two gymnasts, physical changes associated with retirement were a further source of distress. The challenge of athletic retirement was intensified because the gymnasts had heavily invested in sport during adolescence, a period demarcated for the pursuit of an identity. Furthermore, their retirement coincided with a time when adolescents typically undergo profound changes physiologically. Practical suggestions to facilitate athletes' disengagement from sport are discussed

    Keeping it Real : An Evaluation Audit of Five Years of Youth-led Program Evaluation

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    Youth are increasingly seen as competent in participating in research and program evaluation, two activities previously reserved for adults. This paper is a report of the findings from an evaluation audit of Stand Up! Help Out!, a participatory action after-school youth leadership development program for disadvantaged urban youth that utilized youth evaluations to develop a best practices service model. The youths’ feedback assisted providers in improving services so that youth engagement in the program was 99% (by comparison with national highs of 79%). Here, we describe an important aspect of the process of youth-led program evaluation leading to such high youth engagement: How youth interviewed each other so as to optimize the authenticity of their program evaluations and contributions to program design. Drawing from over five years of program evaluation data collected by youth, the authors report on the youths’ experiences as informants and co-researchers, consider strategies used to help youth best describe their experiences in the program, and describe implications for other settings looking to incorporate youth-led program evaluation. Youth-led program evaluation has considerable promise for helping service providers make programs more meaningful for disadvantaged youth

    Early Detection of Ovarian Cancer using the Risk of Ovarian Cancer Algorithm with Frequent CA125 Testing in Women at Increased Familial Risk – Combined Results from Two Screening Trials

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    Purpose: Women at familial/genetic ovarian cancer risk often undergo screening despite unproven efficacy. Research suggests each woman has her own CA125 baseline; significant increases above this level may identify cancers earlier than standard 6- to 12-monthly CA125 > 35 U/mL. Experimental Design: Data from prospective Cancer Genetics Network and Gynecologic Oncology Group trials, which screened 3,692 women (13,080 woman-screening years) with a strong breast/ovarian cancer family history or BRCA1/2 mutations, were combined to assess a novel screening strategy. Specifically, serum CA125 q3 months, evaluated using a risk of ovarian cancer algorithm (ROCA), detected significant increases above each subject's baseline, which triggered transvaginal ultrasound. Specificity and positive predictive value (PPV) were compared with levels derived from general population screening (specificity 90%, PPV 10%), and stage-at-detection was compared with historical high-risk controls. Results: Specificity for ultrasound referral was 92% versus 90% ( P = 0.0001), and PPV was 4.6% versus 10% ( P > 0.10). Eighteen of 19 malignant ovarian neoplasms [prevalent = 4, incident = 6, risk-reducing salpingo-oophorectomy (RRSO) = 9] were detected via screening or RRSO. Among incident cases (which best reflect long-term screening performance), three of six invasive cancers were early-stage (I/II; 50% vs. 10% historical BRCA1 controls; P = 0.016). Six of nine RRSO-related cases were stage I. ROCA flagged three of six (50%) incident cases before CA125 exceeded 35 U/mL. Eight of nine patients with stages 0/I/II ovarian cancer were alive at last follow-up (median 6 years). Conclusions: For screened women at familial/genetic ovarian cancer risk, ROCA q3 months had better early-stage sensitivity at high specificity, and low yet possibly acceptable PPV compared with CA125 > 35 U/mL q6/q12 months, warranting further larger cohort evaluation. Clin Cancer Res; 23(14); 3628-37. ©2017 AACR

    Mitochondrial Dysfunction and Apoptosis in Cumulus Cells of Type I Diabetic Mice

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    Impaired oocyte quality has been demonstrated in diabetic mice; however, the potential pathways by which maternal diabetes exerts its effects on the oocyte are poorly understood. Cumulus cells are in direct contact with the oocyte via gap junctions and provide essential nutrients to support oocyte development. In this study, we investigated the effects of maternal diabetes on the mitochondrial status in cumulus cells. We found an increased frequency of fragmented mitochondria, a decreased transmembrane potential and an aggregated distribution of mitochondria in cumulus cells from diabetic mice. Furthermore, while mitochondrial biogenesis in cumulus cells was induced by maternal diabetes, their metabolic function was disrupted as evidenced by lower ATP and citrate levels. Moreover, we present evidence suggesting that the mitochondrial impairments induced by maternal diabetes, at least in part, lead to cumulus cell apoptosis through the release of cytochrome c. Together the deleterious effects on cumulus cells may disrupt trophic and signaling interactions with the oocyte, contributing to oocyte incompetence and thus poor pregnancy outcomes in diabetic females

    Pathologic Findings at Risk-Reducing Salpingo-Oophorectomy: Primary Results From Gynecologic Oncology Group Trial GOG-0199

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    Risk-reducing salpingo-oophorectomy (RRSO) lowers mortality from ovarian/tubal and breast cancers among BRCA1/2 mutation carriers. Uncertainties persist regarding potential benefits of RRSO among high-risk noncarriers, optimal surgical age, and anatomic origin of clinically occult cancers detected at surgery. To address these topics, we analyzed surgical treatment arm results from Gynecologic Oncology Group Protocol-0199 (GOG-0199), the National Ovarian Cancer Prevention and Early Detection Study

    Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

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    A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

    A case-only study to identify genetic modifiers of breast cancer risk for BRCA1/BRCA2 mutation carriers.

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    Breast cancer (BC) risk for BRCA1 and BRCA2 mutation carriers varies by genetic and familial factors. About 50 common variants have been shown to modify BC risk for mutation carriers. All but three, were identified in general population studies. Other mutation carrier-specific susceptibility variants may exist but studies of mutation carriers have so far been underpowered. We conduct a novel case-only genome-wide association study comparing genotype frequencies between 60,212 general population BC cases and 13,007 cases with BRCA1 or BRCA2 mutations. We identify robust novel associations for 2 variants with BC for BRCA1 and 3 for BRCA2 mutation carriers, P < 10-8, at 5 loci, which are not associated with risk in the general population. They include rs60882887 at 11p11.2 where MADD, SP11 and EIF1, genes previously implicated in BC biology, are predicted as potential targets. These findings will contribute towards customising BC polygenic risk scores for BRCA1 and BRCA2 mutation carriers
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