1,385 research outputs found

    Dynamics and structure of an aging binary colloidal glass

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    We study aging in a colloidal suspension consisting of micron-sized particles in a liquid. This system is made glassy by increasing the particle concentration. We observe samples composed of particles of two sizes, with a size ratio of 1:2.1 and a volume fraction ratio 1:6, using fast laser scanning confocal microscopy. This technique yields real-time, three-dimensional movies deep inside the colloidal glass. Specifically, we look at how the size, motion and structural organization of the particles relate to the overall aging of the glass. Particles move in spatially heterogeneous cooperative groups. These mobile regions tend to be richer in small particles, and these small particles facilitate the motion of nearby particles of both sizes.Comment: 7 pages; submitted to Phys. Rev. E. Revised with 1 new figure, improved tex

    Using non-participant observation to uncover mechanisms: insights from a realist evaluation

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    This article outlines how a realist evaluation of dementia care in hospitals used non-participant observation to support the refinement and testing of mechanisms likely to lead to the use of person-centred care. We found that comments and explanations of their actions from hospital staff during observation periods provided insights into the reasoning that generated their actions for care in real time. This informed subsequent data collection and analysis. Two worked examples of mechanisms first identified during non-participant observation demonstrate (1) how they were uncovered, and (2) how this informed research activities for theory refinement. Early, iterative engagement with the analytic process, primarily involving reflection and debate with the research team, maximised the potential of observation data to support surfacing underlying mechanisms, linking them to specific contexts and outcomes.Peer reviewedFinal Accepted Versio

    Mutual Fund Survivorship

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    This article provides a comprehensive study of survivorship issues using the mutual fund data of Carhart (1997). We demonstrate theoretically that when survival depends on multiperiod performance, the survivorship bias in average performance typically increases with the sample length. This is empirically relevant because evidence suggests a multiyear survival rule for U.S. mutual funds. In the data we find the annual bias increases from 0.07% for 1-year samples to 1% for samples longer than 15 years. We find that survivor conditioning weakens evidence of performance persistence. Finally, we explain how survivor conditioning affects the relation between performance and fund characteristics

    Coverage Gains for Children: Increased Participation in Medicaid and CHIP in 2009

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    Updates analyses of patterns in Medicaid and Children's Health Insurance Program enrollment by state, including increases due to eligibility expansion and those due to income declines. Offers insights into Medicaid expansion under healthcare reform

    Implementation of a Journal Prototype for Pregnant and Parenting Adolescents

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    Teenage pregnancy and childbearing remain pressing public health issues that have garnered attention from public health officials and social services agencies. This paper reports on the initial implementation and formative evaluation of a journaling program used as a means of communicating health information to pregnant and parenting adolescents (young women age 15-19) while also providing participants with a means of self-expression. The journaling prototype was implemented in a community-based agency in the Midwest by Family Support Specialists (FSSs) who made home visits on a monthly basis to assist pregnant and parenting adolescents (n = 52) with successful family planning and public health education. A mixed method approach of qualitative (analysis of journals, field notes, and responses of semi-structured interviews with FSSs) and quantitative (questionnaires from pregnant and parenting adolescent respondents) data with purposive sampling was employed to evaluate the implementation of the journaling intervention. Twenty of the 52 study participants were pregnant when the journaling intervention was implemented, while 32 were not pregnant, but recently had a child and were currently parenting. Two core themes emerged from analysis of the data after the implementation of the journals: (1) usefulness of the journal and responsiveness to participants' information needs and (2) functionality challenges. The results offer practical starting points to tailor the implementation of journaling in other contexts. Further, areas for improvement emerged regarding the distribution timeline for the journal and the content of the journal itself. As such, we discuss the lessons learned through this collaborative project and suggest opportunities for future phases of the journal intervention

    Test–retest reliability of the Friedreich’s ataxia rating scale

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    The modified Friedreich Ataxia Rating Scale (mFARS) is a disease specific, exam-based neurological rating scale commonly used as a outcome measure in clinical trials. While extensive clinimetric testing indicates it’s validity in measuring disease progression, formal test–retest reliability was lacking. To fill this gap, we acquired results from screening and baseline visits of several large clinical trials and calculated intraclass correlation coefficients, coefficients of variance, standard error, and the minimally detectable changes. This study demonstrated excellent test–retest reliability of the mFARS, and it’s upright stability subscore.Fil: Rummey, Christian. Clinical Data Science Gmbh; SuizaFil: Zesiewicz, Theresa A.. University of South Florida; ArgentinaFil: Perez Lloret, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Farmer, Jennifer M.. Friedreich Ataxia Research Alliance; Estados UnidosFil: Pandolfo, Massimo. Université Libre de Bruxelles; BélgicaFil: Lynch, David R.. Children’s Hospital of Philadelphia; Estados Unido

    Going Beyond Promoting: Preparing Students to Creatively Solve Future Problems

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    While we cannot know what problems the future will bring, we can be almost certain that solving them will require creativity. In this article we describe how our course, a first-year undergraduate mathematics course, supports creative problem solving. Creative problem solving cannot be learned through a single experience, so we provide our students with a blend of experiences. We discuss how the course structure enables creative problem solving through class instruction, during class activities, during out of class assessments, and during in class assessments. We believe this course structure increases student comfort with solving open-ended and ill-defined problems similar to what they will encounter in the real world

    Costs of care for persons with opioid dependence in commercial integrated health systems

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    BACKGROUND: When used in general medical practices, buprenorphine is an effective treatment for opioid dependence, yet little is known about how use of buprenorphine affects the utilization and cost of health care in commercial health systems. METHODS: The objective of this retrospective cohort study was to examine how buprenorphine affects patterns of medical care, addiction medicine services, and costs from the health system perspective. Individuals with two or more opioid-dependence diagnoses per year, in two large health systems (System A: n = 1836; System B: n = 4204) over the time span 2007–2008 were included. Propensity scores were used to help adjust for group differences. RESULTS: Patients receiving buprenorphine plus addiction counseling had significantly lower total health care costs than patients with little or no addiction treatment (mean health care costs with buprenorphine treatment = 13,578;vs.meanhealthcarecostswithnoaddictiontreatment=13,578; vs. mean health care costs with no addiction treatment = 31,055; p < .0001), while those receiving buprenorphine plus addiction counseling and those with addiction counseling only did not differ significantly in total health care costs (mean costs with counseling only: $17,017; p = .5897). In comparison to patients receiving buprenorphine plus counseling, those with little or no addiction treatment had significantly greater use of primary care (p < .001), other medical visits (p = .001), and emergency services (p = .020). Patients with counseling only (compared to patients with buprenorphine plus counseling) used less inpatient detoxification (p < .001), and had significantly more PC visits (p = .001), other medical visits (p = .005), and mental health visits (p = .002). CONCLUSIONS: Buprenorphine is a viable alternative to other treatment approaches for opioid dependence in commercial integrated health systems, with total costs of health care similar to abstinence-based counseling. Patients with buprenorphine plus counseling had reduced use of general medical services compared to the alternatives

    Cancer Incidence among Pesticide Applicators Exposed to Cyanazine in the Agricultural Health Study

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    BACKGROUND: Cyanazine is a common pesticide used frequently in the United States during the 1980s and 1990s. Animal and human studies have suggested that triazines may be carcinogenic, but results have been mixed. We evaluated cancer incidence in cyanazine-exposed pesticide applicators among the 57,311 licensed pesticide applicators in the Agricultural Health Study (AHS). METHODS: We obtained detailed pesticide exposure information from a self-administered questionnaire completed at enrollment (1993–1997). Cancer incidence was followed through January 2002. Over half of cyanazine-exposed applicators had ≥ 6 years of exposure at enrollment, and approximately 85% had begun using cyanazine before the 1990s. We used adjusted Poisson regression to calculate rate ratios (RRs) and 95% confidence intervals (CIs) of multiple cancer sites among cyanazine-exposed applicators. We calculated p(trend) values, and all statistical tests were two-sided. Two exposure metrics were used: tertiles of lifetime days of exposure (LD) and intensity-weighted LD. RESULTS: A total of 20,824 cancer-free AHS applicators reported ever using cyanazine at enrollment. Cancer incidence comparisons between applicators with the lowest cyanazine exposure and those with the highest exposure yielded the following for the LD metric: all cancers, RR = 0.99 (95% CI, 0.80–1.24); prostate cancer, RR = 1.23 (95% CI, 0.87–1.70); all lymphohematopoietic cancers, RR = 0.92 (95% CI, 0.50–1.72); non-Hodgkin lymphoma, RR = 1.25 (95% CI, 0.47–3.35); lung cancer, RR = 0.52 (95% CI, 0.22–1.25). CONCLUSIONS: We did not find any clear, consistent associations between cyanazine exposure and any cancer analyzed. The number of sites was small for certain cancers, limiting any conclusion with regard to ovarian, breast, and some other cancers
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