1,553 research outputs found

    Development, Justification, and use of a Projection Operator in Path Integral Calculations in Continuous Space

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    A projection operator, similar to one previously used by us for problems with a finite set of basis functions, is suggested for use with continuous basis sets. This projection operator requires knowledge of the nodes of the density matrix at all temperatures. We show that a class of nodes, determined from the noninteracting density matrix and present at high temperatures in the interacting system are preserved to first order in the interaction at low temperatures. While we cannot show that the nodes are present at intermediate temperatures, we suspect they do exist and, as a test of this conjecture, we perform a calculation of two electrons confined in a harmonic well, using the projection operator. We find that accurate results are obtained at a range of temperatures, suggesting that our conjecture is indeed correct. We find that the error limits determined using the projection operator are 1–2 times smaller than those obtained with straightforward Monte Carlo integration (corresponding to a reduction in time of 1–4 in obtaining a desired level of accuracy)

    U.S. Women's Intended Sources for Reproductive Health Care

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    Introduction: The current sociopolitical climate and context of the Affordable Care Act have led some to question the future role of family planning clinics in reproductive health care. We explored where women plan to get their future contraception, pelvic exam/pap smears, and sexually transmitted infection testing, with a focus on the role of family planning clinics. Methods: Data were drawn from a study of United States adults conducted in January 2013 from a national online panel. We focused on English-literate women aged 18?45 years who answered items on intended sources of care (private office/health maintenance organization [HMO], family planning clinic, other, would not get care) for reproductive health services. We used Rao-Scott F tests to compare intended sources across sociodemographic groups, and logistic regression to model odds of intending to use family planning clinics. Probability weights were used to adjust for the complex sampling design. Results: The response rate was 61% (n?=?2,182). Of the 723 respondents who met the inclusion criteria, approximately half intended to use private offices/HMOs. Among some subgroups, including less educated (less than high school), lower annual incomes (<$25,000) and uninsured women, the proportion intending to use family planning clinics was higher than the proportion intending to use private office/HMO in unadjusted analyses. Across all service types, unmarried and uninsured status were associated with intention to use family planning clinics in multivariable models. Conclusions: While many women intend to use private offices/HMOs for their reproductive health care, family planning clinics continue to play an important role, particularly for socially disadvantaged women.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140133/1/jwh.2014.5116.pd

    Monitoring Direct Effects of Delta, Atlas, and Titan Launches from Cape Canaveral Air Station

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    Launches of Delta, Atlas, and Titan rockets from Cape Canaveral Air Station (CCAS) have potential environmental effects that could arise from direct impacts of the launch exhaust (e.g., blast, heat), deposition of exhaust products of the solid rocket motors (hydrogen chloride, aluminum oxide), or other effects such as noise. Here we: 1) review previous reports, environmental assessments, and environmental impact statements for Delta, Atlas, and Titan vehicles and pad areas to clarity the magnitude of potential impacts; 2) summarize observed effects of 15 Delta, 22 Atlas, and 8 Titan launches; and 3) develop a spatial database of the distribution of effects from individual launches and cumulative effects of launches. The review of previous studies indicated that impacts from these launches can occur from the launch exhaust heat, deposition of exhaust products from the solid rocket motors, and noise. The principal effluents from solid rocket motors are hydrogen chloride (HCl), aluminum oxide (Al2O3), water (H2O), hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2). The exhaust plume interacts with the launch complex structure and water deluge system to generate a launch cloud. Fall out or rain out of material from this cloud can produce localized effects from acid or particulate deposition. Delta, Atlas, and Titan launch vehicles differ in the number and size of solid rocket boosters and in the amount of deluge water used. All are smaller and use less water than the Space Shuttle. Acid deposition can cause damage to plants and animals exposed to it, acidify surface water and soil, and cause long-term changes to community composition and structure from repeated exposure. The magnitude of these effects depends on the intensity and frequency of acid deposition

    Establishing Foundation Archives: A Reader and Guide to First Steps

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    This publication is an anthology of papers presented at a conference held at the Rockefeller Archive Center in January 1990, and sponsored by the Council on Foundations. This collaboration of the Archive Center and the Council provided a rare opponunity for foundations to learn both why preserving documents is imponant and how several foundations have approached finding a repository or setting up and managing an archives. Participants in the conference had the added privilege of conferring with experts and seeing an operating archive as they toured the Rockefeller Archive Center.Foundations are institutions that are shaping private initiatives for the public good, so documenting this aspect of American society falls uniquely under the stewardship of the organizations themselves. Foundation documents often provide the only surviving records of the important contributions of nonprofits and foundations to civic life. These records will help to inform future judgments and ensure that the history of the field is not lost. The publication of this volume was intended to make the information shared at the conference more widely available and to provide an entry point and a primer for foundations as they begin their records and archives journey

    Evaluation Research and Institutional Pressures: Challenges in Public-Nonprofit Contracting

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    This article examines the connection between program evaluation research and decision-making by public managers. Drawing on neo-institutional theory, a framework is presented for diagnosing the pressures and conditions that lead alternatively toward or away the rational use of evaluation research. Three cases of public-nonprofit contracting for the delivery of major programs are presented to clarify the way coercive, mimetic, and normative pressures interfere with a sound connection being made between research and implementation. The article concludes by considering how public managers can respond to the isomorphic pressures in their environment that make it hard to act on data relating to program performance.This publication is Hauser Center Working Paper No. 23. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers

    Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk.

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    Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of Type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single-nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1184 genotyped and imputed SNPs in 6608 Caucasian cases and 37 925 controls, and 895 Asian cases and 1968 controls, revealed the best signal of association for SNP rs11263763 (P = 8.4 × 10(-14), odds ratio = 0.86, 95% confidence interval = 0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumor samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high-to-moderate linkage disequilibrium as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression
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