127 research outputs found

    The Thermal Design, Characterization, and Performance of the SPIDER Long-Duration Balloon Cryostat

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    We describe the SPIDER flight cryostat, which is designed to cool six millimeter-wavelength telescopes during an Antarctic long-duration balloon flight. The cryostat, one of the largest to have flown on a stratospheric payload, uses liquid helium-4 to deliver cooling power to stages at 4.2 and 1.6 K. Stainless steel capillaries facilitate a high flow impedance connection between the main liquid helium tank and a smaller superfluid tank, allowing the latter to operate at 1.6 K as long as there is liquid in the 4.2 K main tank. Each telescope houses a closed cycle helium-3 adsorption refrigerator that further cools the focal planes down to 300 mK. Liquid helium vapor from the main tank is routed through heat exchangers that cool radiation shields, providing negative thermal feedback. The system performed successfully during a 17 day flight in the 2014-2015 Antarctic summer. The cryostat had a total hold time of 16.8 days, with 15.9 days occurring during flight.Comment: 15 pgs, 17 fig

    Transition from reciprocal cooperation to persistent behaviour in social dilemmas at the end of adolescence.

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    While human societies are extraordinarily cooperative in comparison with other social species, the question of why we cooperate with unrelated individuals remains open. Here we report results of a lab-in-the-field experiment with people of different ages in a social dilemma. We find that the average amount of cooperativeness is independent of age except for the elderly, who cooperate more, and a behavioural transition from reciprocal, but more volatile behaviour to more persistent actions towards the end of adolescence. Although all ages react to the cooperation received in the previous round, young teenagers mostly respond to what they see in their neighbourhood regardless of their previous actions. Decisions then become more predictable through midlife, when the act of cooperating or not is more likely to be repeated. Our results show that mechanisms such as reciprocity, which is based on reacting to previous actions, may promote cooperation in general, but its influence can be hindered by the fluctuating behaviour in the case of children

    Integrated HIV Testing, Malaria, and Diarrhea Prevention Campaign in Kenya: Modeled Health Impact and Cost-Effectiveness

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    Efficiently delivered interventions to reduce HIV, malaria, and diarrhea are essential to accelerating global health efforts. A 2008 community integrated prevention campaign in Western Province, Kenya, reached 47,000 individuals over 7 days, providing HIV testing and counseling, water filters, insecticide-treated bed nets, condoms, and for HIV-infected individuals cotrimoxazole prophylaxis and referral for ongoing care. We modeled the potential cost-effectiveness of a scaled-up integrated prevention campaign.We estimated averted deaths and disability-adjusted life years (DALYs) based on published data on baseline mortality and morbidity and on the protective effect of interventions, including antiretroviral therapy. We incorporate a previously estimated scaled-up campaign cost. We used published costs of medical care to estimate savings from averted illness (for all three diseases) and the added costs of initiating treatment earlier in the course of HIV disease.Per 1000 participants, projected reductions in cases of diarrhea, malaria, and HIV infection avert an estimated 16.3 deaths, 359 DALYs and 85,113inmedicalcarecosts.EarliercareforHIVinfectedpersonsaddsanestimated82DALYsaverted(toatotalof442),atacostof85,113 in medical care costs. Earlier care for HIV-infected persons adds an estimated 82 DALYs averted (to a total of 442), at a cost of 37,097 (reducing total averted costs to 48,015).Accountingfortheestimatedcampaigncostof48,015). Accounting for the estimated campaign cost of 32,000, the campaign saves an estimated 16,015per1000participants.Inmultivariatesensitivityanalyses,8316,015 per 1000 participants. In multivariate sensitivity analyses, 83% of simulations result in net savings, and 93% in a cost per DALY averted of less than 20.A mass, rapidly implemented campaign for HIV testing, safe water, and malaria control appears economically attractive

    Prevalence of Dysglycemia Among Coronary Artery Bypass Surgery Patients with No Previous Diabetic History

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    <p>Abstract</p> <p>Background</p> <p>Dysglycemia is a major risk factor for atherosclerosis. In many patient populations dysglycemia is under-diagnosed. Patients with severe coronary artery disease commonly have dysglycemia and there is growing evidence that dysglycemia, irrespective of underlying history of diabetes, is associated with adverse outcome in coronary artery bypass graft (CABG) surgery patients, including longer hospital stay, wound infections, and higher mortality. As HbA1c is an easy and reliable way of checking for dysglycemia we routinely screen all patients undergoing CABG for elevations in HbA1c. Our hypothesis was that a substantial number of patients with dysglycemia that could be identified at the time of cardiothoracic surgery despite having no apparent history of diabetes.</p> <p>Methods</p> <p>1045 consecutive patients undergoing CABG between 2007 and 2009 had HbA1c measured pre-operatively. The 2010 American Diabetes Association (ADA) diagnostic guidelines were used to categorize patients with no known history of diabetes as having diabetes (HbA1c ≥ 6.5%) or increased risk for diabetes (HbA1c 5.7-6.4%).</p> <p>Results</p> <p>Of the 1045 patients with pre-operative HbA1c measurements, 40% (n = 415) had a known history of diabetes and 60% (n = 630) had no known history of diabetes. For the 630 patients with no known diabetic history: 207 (32.9%) had a normal HbA1c (< 5.7%); 356 (56.5%) had an HbA1c falling in the increased risk for diabetes range (5.7-6.4%); and 67 (10.6%) had an HbA1c in the diabetes range (6.5% or higher). In this study the only conventional risk factor that was predictive of high HbA1c was BMI. We also found a high HbA1c irrespective of history of DM was associated with severe coronary artery disease as indicated by the number of vessels revascularized.</p> <p>Conclusion</p> <p>Among individuals undergoing CABG with no known history of diabetes, there is a substantial amount of undiagnosed dysglycemia. Even though labeling these patients as "diabetic" or "increased risk for diabetes" remains controversial in terms of perioperative management, pre-operative screening could lead to appropriate post-operative follow up to mitigate short-term adverse outcome and provide high priority medical referrals of this at risk population.</p

    Targeting FGFR4 Inhibits Hepatocellular Carcinoma in Preclinical Mouse Models

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    The fibroblast growth factor (FGF)-FGF receptor (FGFR) signaling system plays critical roles in a variety of normal developmental and physiological processes. It is also well documented that dysregulation of FGF-FGFR signaling may have important roles in tumor development and progression. The FGFR4–FGF19 signaling axis has been implicated in the development of hepatocellular carcinomas (HCCs) in mice, and potentially in humans. In this study, we demonstrate that FGFR4 is required for hepatocarcinogenesis; the progeny of FGF19 transgenic mice, which have previously been shown to develop HCCs, bred with FGFR4 knockout mice fail to develop liver tumors. To further test the importance of FGFR4 in HCC, we developed a blocking anti-FGFR4 monoclonal antibody (LD1). LD1 inhibited: 1) FGF1 and FGF19 binding to FGFR4, 2) FGFR4–mediated signaling, colony formation, and proliferation in vitro, and 3) tumor growth in a preclinical model of liver cancer in vivo. Finally, we show that FGFR4 expression is elevated in several types of cancer, including liver cancer, as compared to normal tissues. These findings suggest a modulatory role for FGFR4 in the development and progression of hepatocellular carcinoma and that FGFR4 may be an important and novel therapeutic target in treating this disease

    The Evolution of Religion: How Cognitive By-Products, Adaptive Learning Heuristics, Ritual Displays, and Group Competition Generate Deep Commitments to Prosocial Religio

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    Understanding religion requires explaining why supernatural beliefs, devotions, and rituals are both universal and variable across cultures, and why religion is so often associated with both large-scale cooperation and enduring group conflict. Emerging lines of research suggest that these oppositions result from the convergence of three processes. First, the interaction of certain reliably developing cognitive processes, such as our ability to infer the presence of intentional agents, favors—as an evolutionary by-product—the spread of certain kinds of counterintuitive concepts. Second, participation in rituals and devotions involving costly displays exploits various aspects of our evolved psychology to deepen people's commitment to both supernatural agents and religious communities. Third, competition among societies and organizations with different faith-based beliefs and practices has increasingly connected religion with both within-group prosociality and between-group enmity. This connection has strengthened dramatically in recent millennia, as part of the evolution of complex societies, and is important to understanding cooperation and conflict in today's world
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