3,584 research outputs found

    Unified Geostatistical Modeling for Data Fusion and Spatial Heteroskedasticity with R Package ramps

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    This article illustrates usage of the ramps R package, which implements the reparameterized and marginalized posterior sampling (RAMPS) algorithm for complex Bayesian geostatistical models. The RAMPS methodology allows joint modeling of areal and point-source data arising from the same underlying spatial process. A reparametrization of variance parameters facilitates slice sampling based on simplexes, which can be useful in general when multiple variances are present. Prediction at arbitrary points can be made, which is critical in applications where maps are needed. Our implementation takes advantage of sparse matrix operations in the Matrix package and can provide substantial savings in computing time for large datasets. A user-friendly interface, similar to the nlme mixed effects models package, enables users to analyze datasets with little programming effort. Support is provided for numerous spatial and spatiotemporal correlation structures, user-defined correlation structures, and non-spatial random effects. The package features are illustrated via a synthetic dataset of spatially correlated observation distributed across the state of Iowa, USA.

    New graduate registered nurses in public health

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    This presentation investigates the following objectives: 1) to discuss current challenges facing the public health nursing profession; 2) to synthesize existing literature regarding new graduate registered nurses (RNs) in public health; 3) to present the benefits of hiring new graduate RNs with baccalaureate degrees into public health agencies; 4) to utilize existing literature to suggest support measures that will optimize new graduate RNs’ success in public health

    A novel profluorescent dinitroxide for imaging polypropylene degradation

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    Free-radical processes underpin the thermo-oxidative degradation of polyolefins. Thus, to extend the lifetime of these polymers, stabilizers are generally added during processing to scavenge the free radicals formed as the polymer degrades. Nitroxide radical precursors, such as hindered amine stabilizers (HAS),1,2 are common polypropylene additives as the nitroxide moiety is a potent scavenger of polymer alkyl radicals (R„). Oxidation of HAS by radicals formed during polypropylene degradation yields nitroxide radicals (RRï‚ąNO„), which rapidly trap the polymer degradation species to produce alkoxyamines, thus retarding oxidative polymer degradation. This increase in polymer stability is demonstrated by a lengthening of the “induction period” of the polymer (the time prior to a sharp rise in the oxidation of the polymer). Instrumental techniques such as chemiluminescence or infrared spectroscopy are somewhat limited in detecting changes in the polymer during the initial stages of degradation. Therefore, other methods for observing polymer degradation have been sought as the useful life of a polymer does not extend far beyond its “induction period

    Software Reuse Issues

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    NASA Langley Research Center sponsored a Workshop on NASA Research in Software Reuse on November 17-18, 1988 in Melbourne, Florida, hosted by Software Productivity Solutions, Inc. Participants came from four NASA centers and headquarters, eight NASA contractor companies, and three research institutes. Presentations were made on software reuse research at the four NASA centers; on Eli, the reusable software synthesis system designed and currently under development by SPS; on Space Station Freedom plans for reuse; and on other reuse research projects. This publication summarizes the presentations made and the issues discussed during the workshop

    Unified Geostatistical Modeling for Data Fusion and Spatial Heteroskedasticity with R Package ramps

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    This article illustrates usage of the ramps R package, which implements the reparameterized and marginalized posterior sampling (RAMPS) algorithm for complex Bayesian geostatistical models. The RAMPS methodology allows joint modeling of areal and point-source data arising from the same underlying spatial process. A reparametrization of variance parameters facilitates slice sampling based on simplexes, which can be useful in general when multiple variances are present. Prediction at arbitrary points can be made, which is critical in applications where maps are needed. Our implementation takes advantage of sparse matrix operations in the Matrix package and can provide substantial savings in computing time for large datasets. A user-friendly interface, similar to the nlme mixed effects models package, enables users to analyze datasets with little programming effort. Support is provided for numerous spatial and spatiotemporal correlation structures, user-defined correlation structures, and non-spatial random effects. The package features are illustrated via a synthetic dataset of spatially correlated observation distributed across the state of Iowa, USA

    Delivery of Hepatotrophic Factors Fails to Enhance Longer-Term Survival of Subcutaneously Transplanted Hepatocytes

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    Tissue engineering approaches have been investigated as a strategy for hepatocyte transplantation; however the death of a majority of transplanted cells critically limits success of these approaches. In a previous study, a transient increase in hepatocyte survival was achieved through delivery of vascular endothelial growth factor (VEGF) from the porous polymer scaffold utilized for cell delivery. To enhance longer-term survival of the hepatocytes, this delivery system was modified to additionally deliver epidermal growth factor (EGF) and hepatocyte growth factor (HGF) in a sustained manner. Hepatocytes were subcutaneously implanted in SCID mice on scaffolds containing EGF and/or HGF, in addition to VEGF, and survival was monitored for two weeks. A short-term enhancement of hepatocyte survival was observed after one week and is attributed to VEGF-enhanced vascularization, which was not altered by EGF or HGF. Surprisingly, long-term hepatocyte engraftment was not improved, as survival declined to the level of control conditions for all growth factor combinations after two weeks. This investigation indicates that the survival of hepatocytes transplanted into heterotopic locations is dependent on multiple signals. The delivery system developed for the current study may be useful in elucidating the specific factors controlling this process, and bring therapeutic transplantation of hepatocytes closer to implementation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63254/1/ten.2006.12.235.pd

    Planned mode of birth after previous caesarean section and women's use of psychotropic medication in the first year postpartum:a population-based record linkage cohort study

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    Background: Policy in many high-income settings supports giving pregnant women with previous caesarean section a choice between an elective repeat caesarean section (ERCS) or planning a vaginal birth after previous caesarean (VBAC), provided they have no contraindications to VBAC. Despite the potential for this choice to influence women's mental health, evidence about the associated effect to counsel women and identify potential targets for intervention is limited. This study investigated the association between planned mode of birth after previous caesarean and women's subsequent use of psychotropic medications. Methods: A population-based cohort study of 31 131 women with one or more previous caesarean sections who gave birth to a term singleton in Scotland between 2010 and 2015 with no prior psychotropic medications in the year before birth was conducted using linked Scottish national datasets. Cox regression was used to investigate the association between planned mode of birth and being dispensed psychotropic medications in the first year postpartum adjusted for socio-demographic, medical, pregnancy-related factors and breastfeeding. Results: Planned VBAC (n = 10 220) compared to ERCS (n = 20 911) was associated with a reduced risk of the mother being dispensed any psychotropic medication [adjusted hazard ratio (aHR) 0.85, 95% confidence interval (CI) 0.78–0.92], an antidepressant (aHR 0.83, 95% CI 0.76–0.90), and at least two consecutive antidepressants (aHR 0.83, 95% CI 0.75–0.91) in the first year postpartum. Conclusions: Women giving birth by ERCS were more likely than those having a planned VBAC to be dispensed psychotropic medication including antidepressants in the first year postpartum. Further research is needed to establish the reasons behind this new finding

    Independent and Interactive Associations of Negative Affect, Restraint, and Impulsivity in Relation to Binge Eating Among Women

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    There is growing recognition that impulsivity may serve as an underlying risk factor for binge eating. In addition, the association of impulsivity with binge eating may be moderated by other affective and cognitive risk factors. This study examined independent and interactive associations of negative affect, dietary restraint, and facets of impulsivity with binge eating. A diverse sample of 566 undergraduate women completed online questionnaires of study variables. Results revealed a three-way interaction of negative affect, dietary restraint, and attentional impulsivity in relation to binge eating. Women who were high on each of these three variables reported the greatest levels of binge eating. In addition, a two-way interaction was found for negative affect and nonplanning impulsivity in relation to binge eating, such that nonplanning impulsivity strengthened the association between negative affect and binge eating. Attentional and nonplanning facets of impulsivity may function as an underlying trait-level risk factor interacts with affective and/or cognitive risk (e.g., negative affect, dietary restraint) factors to predict elevated binge eating

    Using Digital Technology for Sexual and Reproductive Health: Are Programs Adequately Considering Risk?

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    Digital technologies provide opportunities for advancing sexual and reproductive health and services but also present potential risks. We propose 4 steps to reducing potential harms: (1) consider potential harms during intervention design, (2) mitigate or minimize potential harms during the design phase, (3) measure adverse outcomes during implementation, and (4) plan how to support those reporting adverse outcomes
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