8,406 research outputs found
A spectroscopic survey for strong galaxy-galaxy lenses
We present a spectroscopic survey for strong galaxy-galaxy lenses. Exploiting
optimal sight-lines to massive, bulge-dominated galaxies at redshifts with wide-field, multifibre spectroscopy, we anticipate the detection of
10-20 lensed Lyman- emitting galaxies at redshifts z \simgreat 3 from
a sample of 2000 deflectors. Initial spectroscopic observations are described
and the prospects for constraining the emission-line luminosity function of the
Lyman- emitting population are outlined
Poor Individual Risk Classification From Adverse Childhood Experiences Screening
Introduction: Adverse childhood experiences confer an increased risk for physical and mental health problems across the population, prompting calls for routine clinical screening based on reported adverse childhood experience exposure. However, recent longitudinal research has questioned whether adverse childhood experiences can accurately identify ill health at an individual level. // Methods: Revisiting data collected for the Adverse Childhood Experience Study between 1995 and 1997, this study derived approximate area under the curve estimates to test the ability of the retrospectively reported adverse childhood experience score to discriminate between adults with and without a range of common health risk factors and disease conditions. Furthermore, the classification accuracy of a recommended clinical definition for high-risk exposure (â„4 versus 0â3 adverse childhood experiences) was evaluated on the basis of sensitivity, specificity, positive and negative predictive values, and positive likelihood ratios. // Results: Across all health outcomes, the levels of discrimination for the continuous adverse childhood experience score ranged from very poor to fair (area under the curve=0.50â0.76). The binary classification of â„4 versus 0â3 adverse childhood experiences yielded high specificity (true-negative detection) and negative predictive values (absence of ill health among low-risk adverse childhood experience groups). However, sensitivity (true-positive detection) and positive predictive values (presence of ill health among high-risk adverse childhood experience groups) were low, whereas positive likelihood ratios suggested only minimal-to-moderate increases in health risks among individuals reporting â„4 adverse childhood experiences versus that among those reporting 0â3. // Conclusions: These findings suggest that screening based on the adverse childhood experience score does not accurately identify those individuals at high risk of health problems. This can lead to both allocation of unnecessary interventions and lack of provision of necessary support
Establishing consensus of position-specific predictors for elite youth soccer in England
Purpose: To construct a valid and reliable methodology for the development of position- specific predictors deemed appropriate for talent identification purposes within elite youth soccer in England. Method: N = 10 experts participated in a three-step modified e-Delphi poll to generate consensus on a series of generic youth player attributes. A follow up electronic survey completed by coaches, scouts and recruitment staff (n = 99) ranked these attributes to specific player- positions. Results: A final list of 44 player attributes found consensus using the three-step modified e-Delphi poll and the findings indicated that player-positional attributes considered most important at the youth phase are more psychological and technical than physiological or anthropometric. Despite âhiddenâ attributes (e.g. coachability, flair, versatility, vision etc) finding consensus on the e-Delphi poll, there was no evidence to support these traits when associated with a specific playing position. Conclusion: For those practitioners responsible for talent recruitment, our findings may provide greater understanding of the multiple attributes required for some playing positions. However, new ecological research is required to assess the veracity of our claims
A Creative Writing Case Study of Gender-Based Violence in Coach Education: Staceyâs Story
Creative nonfiction writing is the literary technique employed in this article to explore insights and assist our understanding of an âallegedâ sexual assault in a sport coach education environment. Creative nonfiction employs various narrative tools: characters, setting, figurative language, sequences of events, plot, sub-plot, and dialogue, designed to render the sensitive and controversial elements of sexual assault significant. Readers are, therefore, invited to engage with Staceyâs Story and reflect on the actions of both the perpetrator(s) and the victim. While there are risks associated with the sharing of stories, especially those which are considered dangerous, it is envisaged that Staceyâs Story will be viewed as an opportunity to develop more critical responses and advance our understanding of gender-based violence in sport
Chemical Vapor Deposition of Tin Sulfide from Diorganotin(IV) Dixanthates
We report the synthesis and single-crystal X-ray characterization of diphenyltin bis(2-methoxyethylxanthate) and diphenyltin bis(iso-butylxanthate). These xanthates have been used as a single-source precursor to deposit tin chalcogenide thin films by aerosol-assisted chemical vapor deposition. Grazing incidence X-ray diffraction and scanning transmission electron microscope imaging coupled with elemental mapping show that films deposited from diphenyltin bis(iso-butylxanthate) contain orthorhombic SnS, while films deposited from diphenyltin bis(2-methoxyethylxanthate) between 400 and 575 °C form a SnS/SnO2 nanocomposite. In synthesizing the thin films, we have also demonstrated an ability to control the band gap of the materials based on composition and deposition temperature
Measuring the effect of enhanced cleaning in a UK hospital : a prospective cross-over study
Increasing hospital-acquired infections have generated much attention over the last decade. There is evidence that hygienic cleaning has a role in the control of hospital-acquired infections. This study aimed to evaluate the potential impact of one additional cleaner by using microbiological standards based on aerobic colony counts and the presence of Staphylococcus aureus including meticillin-resistant S. aureus. We introduced an additional cleaner into two matched wards from Monday to Friday, with each ward receiving enhanced cleaning for six months in a cross-over design. Ten hand-touch sites on both wards were screened weekly using standardised methods and patients were monitored for meticillin-resistant S. aureus infection throughout the year-long study. Patient and environmental meticillin-resistant S. aureus isolates were characterised using molecular methods in order to investigate temporal and clonal relationships. Enhanced cleaning was associated with a 32.5% reduction in levels of microbial contamination at handtouch sites when wards received enhanced cleaning (P < 0.0001: 95% CI 20.2%, 42.9%). Near-patient sites (lockers, overbed tables and beds) were more frequently contaminated with meticillin-resistant S. aureus/S. aureus than sites further from the patient (P = 0.065). Genotyping identified indistinguishable strains from both handtouch sites and patients. There was a 26.6% reduction in new meticillin-resistant S. aureus infections on the wards receiving extra cleaning, despite higher meticillin-resistant S. aureus patient-days and bed occupancy rates during enhanced cleaning periods (P = 0.032: 95% CI 7.7%, 92.3%). Adjusting for meticillin-resistant S. aureus patient-days and based upon nine new meticillin-resistant S. aureus infections seen during routine cleaning, we expected 13 new infections during enhanced cleaning periods rather than the four that actually occurred. Clusters of new meticillin-resistant S. aureus infections were identified 2 to 4 weeks after the cleaner left both wards. Enhanced cleaning saved the hospital ÂŁ30,000 to ÂŁ70,000.Introducing one extra cleaner produced a measurable effect on the clinical environment, with apparent benefit to patients regarding meticillin-resistant S. aureus infection. Molecular epidemiological methods supported the possibility that patients acquired meticillin-resistant S. aureus from environmental sources. These findings suggest that additional research is warranted to further clarify the environmental, clinical and economic impact of enhanced hygienic cleaning as a component in the control of hospital-acquired infection
Sequential Extensions of Causal and Evidential Decision Theory
Moving beyond the dualistic view in AI where agent and environment are
separated incurs new challenges for decision making, as calculation of expected
utility is no longer straightforward. The non-dualistic decision theory
literature is split between causal decision theory and evidential decision
theory. We extend these decision algorithms to the sequential setting where the
agent alternates between taking actions and observing their consequences. We
find that evidential decision theory has two natural extensions while causal
decision theory only has one.Comment: ADT 201
MrsRF: an efficient MapReduce algorithm for analyzing large collections of evolutionary trees
<p>Abstract</p> <p>Background</p> <p>MapReduce is a parallel framework that has been used effectively to design large-scale parallel applications for large computing clusters. In this paper, we evaluate the viability of the MapReduce framework for designing phylogenetic applications. The problem of interest is generating the all-to-all Robinson-Foulds distance matrix, which has many applications for visualizing and clustering large collections of evolutionary trees. We introduce MrsRF (<it>MapReduce Speeds up RF</it>), a multi-core algorithm to generate a <it>t </it>Ă <it>t </it>Robinson-Foulds distance matrix between <it>t </it>trees using the MapReduce paradigm.</p> <p>Results</p> <p>We studied the performance of our MrsRF algorithm on two large biological trees sets consisting of 20,000 trees of 150 taxa each and 33,306 trees of 567 taxa each. Our experiments show that MrsRF is a scalable approach reaching a speedup of over 18 on 32 total cores. Our results also show that achieving top speedup on a multi-core cluster requires different cluster configurations. Finally, we show how to use an RF matrix to summarize collections of phylogenetic trees visually.</p> <p>Conclusion</p> <p>Our results show that MapReduce is a promising paradigm for developing multi-core phylogenetic applications. The results also demonstrate that different multi-core configurations must be tested in order to obtain optimum performance. We conclude that RF matrices play a critical role in developing techniques to summarize large collections of trees.</p
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