8,339 research outputs found

    Adaptive Monotone Shrinkage for Regression

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    We develop an adaptive monotone shrinkage estimator for regression models with the following characteristics: i) dense coefficients with small but important effects; ii) a priori ordering that indicates the probable predictive importance of the features. We capture both properties with an empirical Bayes estimator that shrinks coefficients monotonically with respect to their anticipated importance. This estimator can be rapidly computed using a version of Pool-Adjacent-Violators algorithm. We show that the proposed monotone shrinkage approach is competitive with the class of all Bayesian estimators that share the prior information. We further observe that the estimator also minimizes Stein's unbiased risk estimate. Along with our key result that the estimator mimics the oracle Bayes rule under an order assumption, we also prove that the estimator is robust. Even without the order assumption, our estimator mimics the best performance of a large family of estimators that includes the least squares estimator, constant-λ\lambda ridge estimator, James-Stein estimator, etc. All the theoretical results are non-asymptotic. Simulation results and data analysis from a model for text processing are provided to support the theory.Comment: Appearing in Uncertainty in Artificial Intelligence (UAI) 201

    Does abortion reduce self-esteem and life satisfaction?

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    PurposeThis study aims to assess the effects of obtaining an abortion versus being denied an abortion on self-esteem and life satisfaction.MethodsWe present the first 2.5 years of a 5-year longitudinal telephone-interview study that follows 956 women who sought an abortion from 30 facilities across the USA. We examine the self-esteem and life satisfaction trajectories of women who sought and received abortions just under the facility's gestational age limit, of women who sought and received abortions in their first trimester of pregnancy, and of women who sought abortions just beyond the facility gestational limit and were denied an abortion. We use adjusted mixed effects linear regression analyses to assess whether the trajectories of women who sought and obtained an abortion differ from those who were denied one.ResultsWomen denied an abortion initially reported lower self-esteem and life satisfaction than women who sought and obtained an abortion. For all study groups, except those who obtained first trimester abortions, self-esteem and life satisfaction improved over time. The initially lower levels of self-esteem and life satisfaction among women denied an abortion improved more rapidly reaching similar levels as those obtaining abortions at 6 months to one year after abortion seeking. For women obtaining first trimester abortions, initially higher levels of life satisfaction remained steady over time.ConclusionsThere is no evidence that abortion harms women's self-esteem or life satisfaction in the short term

    Relative proximity of chromosome territories influences chromosome exchange partners in radiation-induced chromosome rearrangements in primary human bronchial epithelial cells

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    Copyright © 2013 The Authors. This article is made available through the Brunel Open Access Publishing Fund. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.Copyright © 2013 The Authors. It is well established that chromosomes exist in discrete territories (CTs) in interphase and are positioned in a cell-type specific probabilistic manner. The relative localisation of individual CTs within cell nuclei remains poorly understood, yet many cancers are associated with specific chromosome rearrangements and there is good evidence that relative territorial position influences their frequency of exchange. To examine this further, we characterised the complexity of radiation-induced chromosome exchanges in normal human bronchial epithelial (NHBE) cells by M-FISH analysis of PCC spreads and correlated the exchanges induced with their preferred interphase position, as determined by 1/2-colour 2D-FISH analysis, at the time of irradiation. We found that the frequency and complexity of aberrations induced were reduced in ellipsoid NHBE cells in comparison to previous observations in spherical cells, consistent with aberration complexity being dependent upon the number and proximity of damaged CTs, i.e. lesion proximity. To ask if particular chromosome neighbourhoods could be identified we analysed all radiation-induced pair-wise exchanges using SCHIP (statistics for chromosome interphase positioning) and found that exchanges between chromosomes (1;13), (9;17), (9;18), (12;18) and (16;21) all occurred more often than expected assuming randomness. All of these pairs were also found to be either sharing similar preferred positions in interphase and/or sharing neighbouring territory boundaries. We also analysed a human small cell lung cancer cell line, DMS53, by M-FISH observing the genome to be highly rearranged, yet possessing rearrangements also involving chromosomes (1;13) and (9;17). Our findings show evidence for the occurrence of non-random exchanges that may reflect the territorial organisation of chromosomes in interphase at time of damage and highlight the importance of cellular geometry for the induction of aberrations of varying complexity after exposure to both low and high-LET radiation.Department of Healt

    Evaluation of the IHS Urban Health Business Office Concept

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    Purpose The Evaluation of the IHS Urban Health Business Office Concept, commonly called the Supplementary Security Income (SSI) Project, was a ten month grant demonstration project that was contracted to the American Indian Health Care Association (AIHCA) by the Indian Health Service (IHS) with cooperation of the Social Security Administration (SSA). The SSA was mandated to increase minority and target population enrollment for SSA benefits. The SSA provided funding to the IHS to oversee a project designed to locate and assist urban American Indians and Alaska Natives (AI/ANs) in applying for SSI. Methods Originally, the project was to be administered from the urban Indian clinics\u27 business offices. Since many urban clinics do not have a business office, AIHCA , IHS, and SSA agreed that locating eligible candidates would be more effectively conducted through established outreach programs. Three urban Indian health programs were chosen as project sites: Minneapolis, Minnesota; Seattle, Washington; and Detroit, Michigan. An AI/AN outreach worker was hired at each site with the responsibility to locate and assist potentially eligible clients from the clinic. The outreach worker reported their findings weekly to the Project Coordinator at AIHCA. Conference calls between the Project Coordinator and outreach workers allowed staff to exchange support and site information. The Project Coordinator made three site visits to each site over the course of the data collection period (March to June 1992). Results A total of 78 people participated in the SSI Project by completing the pre-screening forms and speaking to an outreach worker about the SSI program: 17 from Minneapolis; 13 from Seattle; and 48 from Detroit. Results from this analysis have shown that before this project, 41% of the clients that had completed the intake form had incorrect information about SSI; 17.9% had never heard of SSI before; and 11.5% did not know how to contact SSI. In addition, most staff at the urban Indian health programs had little or no information about SSI. Conclusion The SSI Project has furthered the objectives of the Social Security Administration as well as the American Indian Health Care Association, and has assisted the urban Indian health programs by identifying AI/ANs eligible for SSI as well as other SSA program benefits. This SSI study improved recipients\u27 lives and qualities of life by increasing their income, access to assistance services and health care benefits

    Current management of pregnancy-related low back pain: a national cross-sectional survey of UK physiotherapists.

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    BACKGROUND: Pregnancy-related low back pain (LBP) is very common. Evidence from a systematic review supports the use of exercise and acupuncture, although little is known about the care received by women with pregnancy-related back pain in the UK. OBJECTIVE: To describe current acupuncture and standard care management of pregnancy-related LBP by UK physiotherapists. DESIGN: Cross-sectional survey of physiotherapists with experience of treating women with pregnancy-related LBP from three professional networks of the Chartered Society of Physiotherapy. METHODS: In total, 1093 physiotherapists were mailed a questionnaire. The questionnaire captured respondents' demographic and practice setting information, and experience of managing women with pregnancy-related back pain, and investigated the reported management of pregnancy-related LBP using a patient case vignette of a specific, 'typical' case. RESULTS: The overall response rate was 58% (629/1093). Four hundred and ninety-nine physiotherapists had experience of treating women with pregnancy-related LBP and were included in the analysis. Most respondents worked wholly or partly in the UK National Health Service (78%). Most respondents reported that they treat patients with pregnancy-related LBP in three to four one-to-one treatment sessions over 3 to 6 weeks. The results show that a range of management strategies are employed for pregnancy-related LBP, and multimodal management is common. The most common reported treatment was home exercises (94%), and 24% of physiotherapists reported that they would use acupuncture with the patient described in the vignette. CONCLUSIONS: This study provides the first robust data on the management of pregnancy-related LBP by UK physiotherapists. Multimodal management is common, although exercise is the most frequently used treatment for pregnancy-related LBP. Acupuncture is used less often for this patient group

    Supramolecular structure in the membrane of Staphylococcus aureus

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    The fundamental processes of life are organized and based on common basic principles. Molecular organizers, often interacting with the membrane, capitalize on cellular polarity to precisely orientate essential processes. The study of organisms lacking apparent polarity or known cellular organizers (e.g., the bacterium Staphylococcus aureus) may enable the elucidation of the primal organizational drive in biology. How does a cell choose from infinite locations in its membrane? We have discovered a structure in the S. aureus membrane that organizes processes indispensable for life and can arise spontaneously from the geometric constraints of protein complexes on membranes. Building on this finding, the most basic cellular positioning system to optimize biological processes, known molecular coordinators could introduce further levels of complexity. All life demands the temporal and spatial control of essential biological functions. In bacteria, the recent discovery of coordinating elements provides a framework to begin to explain cell growth and division. Here we present the discovery of a supramolecular structure in the membrane of the coccal bacterium Staphylococcus aureus, which leads to the formation of a large-scale pattern across the entire cell body; this has been unveiled by studying the distribution of essential proteins involved in lipid metabolism (PlsY and CdsA). The organization is found to require MreD, which determines morphology in rod-shaped cells. The distribution of protein complexes can be explained as a spontaneous pattern formation arising from the competition between the energy cost of bending that they impose on the membrane, their entropy of mixing, and the geometric constraints in the system. Our results provide evidence for the existence of a self-organized and nonpercolating molecular scaffold involving MreD as an organizer for optimal cell function and growth based on the intrinsic self-assembling properties of biological molecules

    The Adsorption and Collapse Transitions in a Linear Polymer Chain near an Attractive Wall

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    We deduce the qualitative phase diagram of a long flexible neutral polymer chain immersed in a poor solvent near an attracting surface using phenomenological arguments. The actual positions of the phase boundaries are estimated numerically from series expansion up to 19 sites of a self-attracting self avoiding walk in three dimensions. In two dimensions, we calculate analytically phase boundaries in some cases for a partially directed model. Both the numerical as well as analytical results corroborate the proposed qualitative phase diagram.Comment: 8 pages, 8 figures, revte

    In vitro assembly of xenotropic murine leukemia virus-related virus CA-NC protein

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