181 research outputs found

    Experimental Investigation of Drag Reduction on Automobiles with an Inflatable Boat-Tail

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    There is a growing demand for higher efficiency and more environmentally friendly vehicles, including better fuel economy, reduction in wind noise level, and greater vehicle performance and dynamic stability. These factors vary with aerodynamic performance. Overall, aerodynamic drag contributes to as much as 60% of a vehicles fuel consumption, motivating vehicle manufacturers to investigate new drag reduction applications. When streamlining a vehicle for aerodynamic performance, one method is by boat-tailing, or rear end tapering. This study includes an investigation of the overall potential of a lightweight yet rigid, inflatable drag reduction device, applied to a motor vehicle. Based on original concepts proposed by Toyota Research Institute North American (TRINA), combined with past research of inflatable technology, an inflatable drag reduction device is designed, manufactured, and tested. Peel strength of adhesive bonds testing provides detailed results of proper heat-sealable fabric utilization, and preferred materials are selected for inflatable models. Through multiple concept considerations and varying design stages ergonomic boat-tail designs evolve, as does construction, and manufacturing details are included. The inflatable boat-tail as a drag reduction device is examined through wind tunnel testing at Reynolds numbers O(10^5) by 2D wake survey and conservation of momentum theory, and multiple system designs are compared. Results show 10-80% decreased drag coefficients as a function of varying boat-tail construction compared to a baseline model. Wake survey is also performed at multiple heights along boat-tail sections, and 3D effects are investigated. Further investigations include wake survey velocity profiles as a function of angle of attack. Standard deviation and velocity fluctuations are compared for individual systems, and results are discussed.Mechanical and Aerospace Engineerin

    The PSEA promoter element of the Drosophila U1 snRNA gene is sufficient to bring DmSNAPc into contact with 20 base pairs of downstream DNA

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    Most of the major spliceosomal small nuclear RNAs (snRNAs) (i.e. U1, U2, U4 and U5) are synthesized by RNA polymerase II (pol II). In Drosophila melanogaster, the 5′-flanking DNA of these genes contains two conserved elements: the proximal sequence element A (PSEA) and the proximal sequence element B (PSEB). The PSEA is essential for transcription and is recognized by DmSNAPc, a multi-subunit protein complex. Previous site-specific protein–DNA photo-cross-linking assays demonstrated that one of the subunits of DmSNAPc, DmSNAP43, remains in close contact with the DNA for 20 bp beyond the 3′ end of the PSEA, a region that contains the PSEB. The current work demonstrates that mutation of the PSEB does not abolish the cross-linking of DmSNAP43 to the PSEB. Thus the U1 PSEA alone is capable of bringing DmSNAP43 into close contact with this downstream DNA. However, mutation of the PSEB perturbs the cross-linking pattern. In concordance with these findings, PSEB mutations result in a 2- to 4-fold reduction in U1 promoter activity when assayed by transient transfection

    International perspective on guidelines and policies for child custody and child maltreatment risk evaluations : A preliminary comparative analysis across selected countries in Europe and North America

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    Little knowledge exists on how evaluators in child custody and child maltreatment cases are informed by guidelines, the kinds of qualifications required and the types of training provided in different countries. The purpose of this paper is to provide an international preliminary comparison on how child custody and child maltreatment risk assessments are conducted in selected Western countries, and how the assessments are informed by best practice guidelines. Another aim is to increase knowledge on how the guidelines and best-practice standards could be developed further to reflect recent research findings. A total number of 18 guidelines were included in the analyses: four from Canada, five from the United States, three from the United Kingdom, three from the Netherlands, two from Finland, and one from Germany. We conducted a content analysis of the included guidelines in the database, focusing on how the guidelines address the best interest of the child criteria, guidelines for conducting the assessments, considerations for evaluative criteria, and specific guidance for conducting specific assessment procedures (e.g., interviews and observations). Findings show that the qualifications of and training provided to evaluators in child custody and child maltreatment risk evaluations are largely heterogeneous across the countries represented. Guidelines differ in whether and how they highlight the importance of evidence-based practices and scientifically validated assessment measures. Implications are drawn from the review and contextualized by international expert authors in the fields of forensic psychology, and family law. After the content analysis, discussion sessions within the expert group were held. The authors provide both commentaries and suggestions to improve the development of standard methods for conducting both child custody and child maltreatment risk evaluations and to consider a more transparent and judicious use of social science research to guide methods and the recommendations offered within these assessments.Peer reviewe

    An ‘economics’ window on an interdisciplinary crisis

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    The euro area crisis cannot be understood without combining insights from a variety of disciplines — economics and political science first and foremost. This introduction aims at explaining how the essays in this collection map onto a number of important debates in political science. We sketch four well-known areas for the political science community: the framework for multilevel governance, the role of ideas in policymaking, the interaction between power politics and distributive bargaining, and the challenge of popular legitimation. These critical themes in the current crisis are important areas of overlap in economic and political analysis. Hence, the aim of this introduction is to show how these themes emerge in the essays that follow

    Temperature-Induced Increase in Methane Release from Peat Bogs: A Mesocosm Experiment

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    Peat bogs are primarily situated at mid to high latitudes and future climatic change projections indicate that these areas may become increasingly wetter and warmer. Methane emissions from peat bogs are reduced by symbiotic methane oxidizing bacteria (methanotrophs). Higher temperatures and increasing water levels will enhance methane production, but also methane oxidation. To unravel the temperature effect on methane and carbon cycling, a set of mesocosm experiments were executed, where intact peat cores containing actively growing Sphagnum were incubated at 5, 10, 15, 20, and 25°C. After two months of incubation, methane flux measurements indicated that, at increasing temperatures, methanotrophs are not able to fully compensate for the increasing methane production by methanogens. Net methane fluxes showed a strong temperature-dependence, with higher methane fluxes at higher temperatures. After removal of Sphagnum, methane fluxes were higher, increasing with increasing temperature. This indicates that the methanotrophs associated with Sphagnum plants play an important role in limiting the net methane flux from peat. Methanotrophs appear to consume almost all methane transported through diffusion between 5 and 15°C. Still, even though methane consumption increased with increasing temperature, the higher fluxes from the methane producing microbes could not be balanced by methanotrophic activity. The efficiency of the Sphagnum-methanotroph consortium as a filter for methane escape thus decreases with increasing temperature. Whereas 98% of the produced methane is retained at 5°C, this drops to approximately 50% at 25°C. This implies that warming at the mid to high latitudes may be enhanced through increased methane release from peat bogs

    Hematopoietic stem and progenitor cells are a distinct HIV reservoir that contributes to persistent viremia in suppressed patients

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    Long-lived reservoirs of persistent HIV are a major barrier to a cure. CD4+ hematopoietic stem and progenitor cells (HSPCs) have the capacity for lifelong survival, self-renewal, and the generation of daughter cells. Recent evidence shows that they are also susceptible to HIV infection in vitro and in vivo. Whether HSPCs harbor infectious virus or contribute to plasma virus (PV) is unknown. Here, we provide strong evidence that clusters of identical proviruses from HSPCs and their likely progeny often match residual PV. A higher proportion of these sequences match residual PV than proviral genomes from bone marrow and peripheral blood mononuclear cells that are observed only once. Furthermore, an analysis of near-full-length genomes isolated from HSPCs provides evidence that HSPCs harbor functional HIV proviral genomes that often match residual PV. These results support the conclusion that HIV-infected HSPCs form a distinct and functionally significant reservoir of persistent HIV in infected people

    Routine Rapid HIV Screening in Six Community Health Centers Serving Populations at Risk

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    In 2006, to increase opportunities for patients to become aware of their HIV status, the Centers for Disease Control and Prevention released updated guidelines for routine, opt-out HIV screening of adults, adolescents, and pregnant women in healthcare settings. To date, there are few documented applications of these recommendations. To measure the impact of application of the guidelines for routine screening in health centers serving communities disproportionately affected by HIV in the southeastern US. A multi-site program implementation study, describing patients tested and not tested and assessing changes in testing frequency before and after new guidelines were implemented. All patients aged 13 to 64 seen in participating health centers. Routine rapid HIV screening in accord with CDC guidelines. The frequency of testing before and after routine screening was in place and demographic differences in offering and receipt of testing. Compared to approximately 3,000 patients in the year prior to implementation, 16,148 patients were offered testing with 10,769 tested. Of 39 rapid tests resulting in preliminary positives, 17 were newly detected infections. Among these patients, 12 of 14 receiving referrals were linked to HIV care. Nineteen were false positives. Younger patients, African Americans and Latinos were more likely to receive testing. By integrating CDC-recommended guidelines and applying rapid test technology, health centers were able to provide new access to HIV testing. Variation across centers in offering and receiving tests may indicate that clinical training could enhance universal access

    Overall Survival With Maintenance Olaparib at a 7-Year Follow-Up in Patients With Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation: The SOLO1/GOG 3004 Trial

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    In SOLO1/GOG 3004 (ClinicalTrials.gov identifier: NCT01844986), maintenance therapy with the poly(ADP-ribose) polymerase inhibitor olaparib provided a sustained progression-free survival benefit in patients with newly diagnosed advanced ovarian cancer and a BRCA1 and/or BRCA2 (BRCA) mutation. We report overall survival (OS) after a 7-year follow-up, a clinically relevant time point and the longest follow-up for any poly(ADP-ribose) polymerase inhibitor in the first-line setting. METHODS: This double-blind phase III trial randomly assigned patients with newly diagnosed advanced ovarian cancer and a BRCA mutation in clinical response to platinum-based chemotherapy to maintenance olaparib (n = 260) or placebo (n = 131) for up to 2 years. A prespecified descriptive analysis of OS, a secondary end point, was conducted after a 7-year follow-up. RESULTS: The median duration of treatment was 24.6 months with olaparib and 13.9 months with placebo, and the median follow-up was 88.9 and 87.4 months, respectively. The hazard ratio for OS was 0.55 (95% CI, 0.40 to 0.76; P = .0004 [P < .0001 required to declare statistical significance]). At 7 years, 67.0% of olaparib patients versus 46.5% of placebo patients were alive, and 45.3% versus 20.6%, respectively, were alive and had not received a first subsequent treatment (Kaplan-Meier estimates). The incidence of myelodysplastic syndrome and acute myeloid leukemia remained low, and new primary malignancies remained balanced between treatment groups. CONCLUSION: Results indicate a clinically meaningful, albeit not statistically significant according to prespecified criteria, improvement in OS with maintenance olaparib in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation and support the use of maintenance olaparib to achieve long-term remission in this setting; the potential for cure may also be enhanced. No new safety signals were observed during long-term follow-up

    International Coercion, Emulation and Policy Diffusion: Market-Oriented Infrastructure Reforms, 1977-1999

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    Why do some countries adopt market-oriented reforms such as deregulation, privatization and liberalization of competition in their infrastructure industries while others do not? Why did the pace of adoption accelerate in the 1990s? Building on neo-institutional theory in sociology, we argue that the domestic adoption of market-oriented reforms is strongly influenced by international pressures of coercion and emulation. We find robust support for these arguments with an event-history analysis of the determinants of reform in the telecommunications and electricity sectors of as many as 205 countries and territories between 1977 and 1999. Our results also suggest that the coercive effect of multilateral lending from the IMF, the World Bank or Regional Development Banks is increasing over time, a finding that is consistent with anecdotal evidence that multilateral organizations have broadened the scope of the “conditionality” terms specifying market-oriented reforms imposed on borrowing countries. We discuss the possibility that, by pressuring countries into policy reform, cross-national coercion and emulation may not produce ideal outcomes.http://deepblue.lib.umich.edu/bitstream/2027.42/40099/3/wp713.pd
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