803 research outputs found
Spectral Variations in Early-Type Galaxies as a Function of Mass
We report on the strengths of three spectral indicators - Mg_2, Hbeta, and
Hn/Fe - in the integrated light of a sample of 100 field and cluster E/S0
galaxies. The measured indices are sensitive to age and/or and metallicity
variations within the galaxy sample. Using linear regression analysis for data
with non-uniform errors, we determine the intrinsic scatter present among the
spectral indices of our galaxy sample as a function of internal velocity
dispersion. Our analysis indicates that there is significantly more intrinsic
scatter in the two Balmer line indices than in the Mg_2 index, indicating that
the Balmer indices provide more dynamic range in determining the age of a
stellar population than does the Mg_2 index. Furthermore, the scatter is much
larger for the low velocity dispersion galaxies, indicating that star formation
has occurred more recently in the lower mass galaxies.Comment: 4 pages, 1 figure, 1 table, to appear in the Astrophysical Journal
Letter
Foraging environment determines the genetic architecture and evolutionary potential of trophic morphology in cichlid fishes
Phenotypic plasticity allows organisms to change their phenotype in response to shifts in the environment. While a central topic in current discussions of evolutionary potential, a comprehensive understanding of the genetic underpinnings of plasticity is lacking in systems undergoing adaptive diversification. Here, we investigate the genetic basis of phenotypic plasticity in a textbook adaptive radiation, Lake Malawi cichlid fishes. Specifically, we crossed two divergent species to generate an F3 hybrid mapping population. At early juvenile stages, hybrid families were split and reared in alternate foraging environments that mimicked benthic/scraping or limnetic/sucking modes of feeding. These alternate treatments produced a variation in morphology that was broadly similar to the major axis of divergence among Malawi cichlids, providing support for the flexible stem theory of adaptive radiation. Next, we found that the genetic architecture of several morphological traits was highly sensitive to the environment. In particular, of 22 significant quantitative trait loci (QTL), only one was shared between the environments. In addition, we identified QTL acting across environments with alternate alleles being differentially sensitive to the environment. Thus, our data suggest that while plasticity is largely determined by loci specific to a given environment, it may also be influenced by loci operating across environments. Finally, our mapping data provide evidence for the evolution of plasticity via genetic assimilation at an important regulatory locus, ptch1. In all, our data address long-standing discussions about the genetic basis and evolution of plasticity. They also underscore the importance of the environment in affecting developmental outcomes, genetic architectures, morphological diversity and evolutionary potential
Spatiotemporally Complete Condensation in a Non-Poissonian Exclusion Process
We investigate a non-Poissonian version of the asymmetric simple exclusion
process, motivated by the observation that coarse-graining the interactions
between particles in complex systems generically leads to a stochastic process
with a non-Markovian (history-dependent) character. We characterize a large
family of one-dimensional hopping processes using a waiting-time distribution
for individual particle hops. We find that when its variance is infinite, a
real-space condensate forms that is complete in space (involves all particles)
and time (exists at almost any given instant) in the thermodynamic limit. The
mechanism for the onset and stability of the condensate are both rather subtle,
and depends on the microscopic dynamics subsequent to a failed particle hop
attempts.Comment: 5 pages, 5 figures. Version 2 to appear in PR
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Cost effectiveness of school-located influenza vaccination programs for elementary and secondary school children.
BackgroundStudies have noted variations in the cost-effectiveness of school-located influenza vaccination (SLIV), but little is known about how SLIV's cost-effectiveness may vary by targeted age group (e.g., elementary or secondary school students), or vaccine consent process (paper-based or web-based). Further, SLIV's cost-effectiveness may be impacted by its spillover effect on practice-based vaccination; prior studies have not addressed this issue.MethodsWe performed a cost-effectiveness analysis on two SLIV programs in upstate New York in 2015-2016: (a) elementary school SLIV using a stepped wedge design with schools as clusters (24 suburban and 18 urban schools) and (b) secondary school SLIV using a cluster randomized trial (16 suburban and 4 urban schools). The cost-per-additionally-vaccinated child (i.e., incremental cost-effectiveness ratio (ICER)) was estimated by dividing the incremental SLIV intervention cost by the incremental effectiveness (i.e., the additional number of vaccinated students in intervention schools compared to control schools). We performed deterministic analyses, one-way sensitivity analyses, and probabilistic analyses.ResultsThe overall effectiveness measure (proportion of children vaccinated) was 5.7 and 5.5 percentage points higher, respectively, in intervention elementary (52.8%) and secondary schools (48.2%) than grade-matched control schools. SLIV programs vaccinated a small proportion of children in intervention elementary (5.2%) and secondary schools (2.5%). In elementary and secondary schools, the ICER excluding vaccine purchase was 86.51 per-additionally-vaccinated-child, respectively. When additionally accounting for observed spillover impact on practice-based vaccination, the ICER decreased to 53.40). These estimates were higher than the published practice-based vaccination cost (median = 45.48). Also, these estimates were higher than our 2009-2011 urban SLIV program mean costs (12.97 per-additionally-vaccinated-child) and higher project coordination costs in 2015-2016. One-way sensitivity analyses showed that ICER estimates were most sensitive to the SLIV effectiveness.ConclusionsSLIV raises vaccination rates and may increase practice-based vaccination in primary care practices. While these SLIV programs are effective, to be as cost-effective as practice-based vaccination our SLIV programs would need to vaccinate more students and/or lower the costs for consent systems and project coordination.Trial registrationClinicalTrials.gov NCT02227186 (August 25, 2014), updated NCT03137667 (May 2, 2017)
Baseline configuration selection, Voyager Task C
This report talks about Baseline Configuration Selection, Voyager Task
Inpatient costs, mortality and 30-day re-admission in patients with central-line-associated bloodstream infections
AbstractPrevious work has suggested that central-line-associated bloodstream infection (CLABSI) is associated with increased costs and risk of mortality; however, no studies have looked at both total and variable costs, and information on outcomes outside of the intensive-care unit (ICU) is sparse. The aim of this study was to determine the excess in-hospital mortality and costs attributable to CLABSI in ICU and non-ICU patients. We conducted a retrospective cohort and cost-of-illness study from the hospital perspective of 398 patients at a tertiary-care academic medical centre from 1 January 2008 to 31 December 2010. All CLABSI patients and a simple random sample drawn from a list of all central lines inserted during the study period were included. Generalized linear models with log link and gamma distribution were used to model costs as a function of CLABSI and important covariates. Costs were adjusted to 2010 US dollars by use of the personal consumption expenditures for medical care index. We used multivariable logistic regression to identify independent predictors of in-hospital mortality. Among both ICU and non-ICU patients, adjusted variable costs for patients with CLABSI were c. $32 000 (2010 US dollars) higher on average than for patients without CLABSI. After we controlled for severity of illness and other healthcare-associated infections, CLABSI was associated with a 2.27-fold (95% CI 1.15–4.46) increased risk of mortality. Other healthcare-associated infections were also significantly associated with greater costs and mortality. Overall, CLABSI was associated with significantly higher adjusted in-hospital mortality and total and variable costs than those for patients without CLABSI
Learning disability today fourth edition: The essential handbook for support staff, service providers, families and carers
This fully revised and updated edition of Learning Disability Today provides an accessible and thought-provoking introduction to some of the key issues in the lives of people with learning disabilities and the practice of those who support them. Learning Disability Today was first published in 2007 to meet the need for a handbook which, while well-grounded in latest research and practice, was accessible for staff occupying many roles, such as support workers and managers in learning disability service settings, community learning disability teams and professionals who may find themselves supporting a person with an intellectual disability from time to time, families and voluntary supporters, as well as students of learning disability/intellectual disability. It has continued to be a highly successful title, and has been published in three previous editions over the past nine years. This new, fourth edition is a complete revision, aiming to address key knowledge requirements, challenges and concerns for people working in the field and provide opportunities for reflection and continuing professional development. The content is illustrated throughout by case studies to help the reader explore how best to address issues in practice
Imputing Amino Acid Polymorphisms in Human Leukocyte Antigens
DNA sequence variation within human leukocyte antigen (HLA) genes mediate susceptibility to a wide range of human diseases. The complex genetic structure of the major histocompatibility complex (MHC) makes it difficult, however, to collect genotyping data in large cohorts. Long-range linkage disequilibrium between HLA loci and SNP markers across the major histocompatibility complex (MHC) region offers an alternative approach through imputation to interrogate HLA variation in existing GWAS data sets. Here we describe a computational strategy, SNP2HLA, to impute classical alleles and amino acid polymorphisms at class I (HLA-A, -B, -C) and class II (-DPA1, -DPB1, -DQA1, -DQB1, and -DRB1) loci. To characterize performance of SNP2HLA, we constructed two European ancestry reference panels, one based on data collected in HapMap-CEPH pedigrees (90 individuals) and another based on data collected by the Type 1 Diabetes Genetics Consortium (T1DGC, 5,225 individuals). We imputed HLA alleles in an independent data set from the British 1958 Birth Cohort (N = 918) with gold standard four-digit HLA types and SNPs genotyped using the Affymetrix GeneChip 500 K and Illumina Immunochip microarrays. We demonstrate that the sample size of the reference panel, rather than SNP density of the genotyping platform, is critical to achieve high imputation accuracy. Using the larger T1DGC reference panel, the average accuracy at four-digit resolution is 94.7% using the low-density Affymetrix GeneChip 500 K, and 96.7% using the high-density Illumina Immunochip. For amino acid polymorphisms within HLA genes, we achieve 98.6% and 99.3% accuracy using the Affymetrix GeneChip 500 K and Illumina Immunochip, respectively. Finally, we demonstrate how imputation and association testing at amino acid resolution can facilitate fine-mapping of primary MHC association signals, giving a specific example from type 1 diabetes
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