768 research outputs found

    Comparing Bayesian Models of Annotation

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    The analysis of crowdsourced annotations in NLP is concerned with identifying 1) gold standard labels, 2) annotator accuracies and biases, and 3) item difficulties and error patterns. Traditionally, majority voting was used for 1), and coefficients of agreement for 2) and 3). Lately, model-based analysis of corpus annotations have proven better at all three tasks. But there has been relatively little work comparing them on the same datasets. This paper aims to fill this gap by analyzing six models of annotation, covering different approaches to annotator ability, item difficulty, and parameter pooling (tying) across annotators and items. We evaluate these models along four aspects: comparison to gold labels, predictive accuracy for new annotations, annotator characterization, and item difficulty, using four datasets with varying degrees of noise in the form of random (spammy) annotators. We conclude with guidelines for model selection, application, and implementation

    Observational measure of implementation progress in community based settings: The Stages of implementation completion (SIC)

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    <p>Abstract</p> <p>Background</p> <p>An increasingly large body of research is focused on designing and testing strategies to improve knowledge about how to embed evidence-based programs (EBP) into community settings. Development of strategies for overcoming barriers and increasing the effectiveness and pace of implementation is a high priority. Yet, there are few research tools that measure the implementation process itself. The Stages of Implementation Completion (SIC) is an observation-based measure that is used to track the time to achievement of key implementation milestones in an EBP being implemented in 51 counties in 53 sites (two counties have two sites) in two states in the United States.</p> <p>Methods</p> <p>The SIC was developed in the context of a randomized trial comparing the effectiveness of two implementation strategies: community development teams (experimental condition) and individualized implementation (control condition). Fifty-one counties were randomized to experimental or control conditions for implementation of multidimensional treatment foster care (MTFC), an alternative to group/residential care placement for children and adolescents. Progress through eight implementation stages was tracked by noting dates of completion of specific activities in each stage. Activities were tailored to the strategies for implementing the specific EBP.</p> <p>Results</p> <p>Preliminary data showed that several counties ceased progress during pre-implementation and that there was a high degree of variability among sites in the duration scores per stage and on the proportion of activities that were completed in each stage. Progress through activities and stages for three example counties is shown.</p> <p>Conclusions</p> <p>By assessing the attainment time of each stage and the proportion of activities completed, the SIC measure can be used to track and compare the effectiveness of various implementation strategies. Data from the SIC will provide sites with relevant information on the time and resources needed to implement MTFC during various phases of implementation. With some modifications, the SIC could be appropriate for use in evaluating implementation strategies in head-to-head randomized implementation trials and as a monitoring tool for rolling out other EBPs.</p

    Isolation and characterization of potent antifungal strains of the Streptomyces violaceusniger clade active against Candida albicans

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    Streptomyces strains were isolated from a sagebrush rhizosphere soil sample on humic acid vitamin (HV) agar and water yeast extract (WYE) agar supplemented with 1.5% (w/w) phenol as a selective medium. Acidic, neutral and alkaline pH conditions were also used in the isolation procedures. The phenol treatment reduced the numbers of both actinomycetes and non-actinomycetes on plates under all three pH conditions. From phenol-amended HV and WYE agar, 16 strains were isolated in pure culture; 14 from the HV agar and two from the WYE agar. All the isolates were tested for their antifungal activities against Pythium ultimum P8 and five yeast strains, including two antifungal drug-resistant Candida albicans strains. HV isolates that showed broad-spectrum antifungal antibiotic activities were all found to be members of the Streptomyces violaceusniger clade, while those that did not were non-clade members. The phenol treatment was not selective for S. violaceusniger clade members. Therefore, we tested the spores of both S. violaceusniger clade and non-clade members using two biocides, phenol and hydrogen peroxide, as selection agents. Spores of non-clade members, such as S. coelicolor M145 and S. lividans TK 21, survived these two biocides just as well as S. violaceusniger clade members. Thus, in our hands, biocide resistance was not S. violaceusniger clade specific as previously reported. However, isolates showing broad-spectrum antifungal and antiyeast activity were all members of the clade. We conclude that screening of isolates for broad-spectrum antifungal/antiyeast activity is the preferred method of isolating S. violaceusniger clade strains rather than biocide-based selection. Phylogenetic analysis of the phenol-resistant isolates revealed that the HV isolates that exhibited broad-spectrum antifungal antibiotic activity were all clustered and closely related to the S. violaceusniger clade, while the isolates that did not exhibit antifungal antibiotic activity were all non-clade members

    Glucose-induced down regulation of thiamine transporters in the kidney proximal tubular epithelium produces thiamine insufficiency in diabetes

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    Increased renal clearance of thiamine (vitamin B1) occurs in experimental and clinical diabetes producing thiamine insufficiency mediated by impaired tubular re-uptake and linked to the development of diabetic nephropathy. We studied the mechanism of impaired renal re-uptake of thiamine in diabetes. Expression of thiamine transporter proteins THTR-1 and THTR-2 in normal human kidney sections examined by immunohistochemistry showed intense polarised staining of the apical, luminal membranes in proximal tubules for THTR-1 and THTR-2 of the cortex and uniform, diffuse staining throughout cells of the collecting duct for THTR-1 and THTR-2 of the medulla. Human primary proximal tubule epithelial cells were incubated with low and high glucose concentration, 5 and 26 mmol/l, respectively. In high glucose concentration there was decreased expression of THTR-1 and THTR-2 (transporter mRNA: βˆ’76% and βˆ’53% respectively, p<0.001; transporter protein βˆ’77% and βˆ’83% respectively, p<0.05), concomitant with decreased expression of transcription factor specificity protein-1. High glucose concentration also produced a 37% decrease in apical to basolateral transport of thiamine transport across cell monolayers. Intensification of glycemic control corrected increased fractional excretion of thiamine in experimental diabetes. We conclude that glucose-induced decreased expression of thiamine transporters in the tubular epithelium may mediate renal mishandling of thiamine in diabetes. This is a novel mechanism of thiamine insufficiency linked to diabetic nephropathy

    Individual Heterogeneity in the Returns to Schooling: Instrumental Variables Quantile Regression Using Twins Data

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    Considerable effort has been exercised in estimating mean returns to education while carefully considering biases arising from unmeasured ability and measurement error. Recent work has investigated whether there are variations from the β€œmean” return to education across the population with mixed results. We use an instrumental variables estimator for quantile regression on a sample of twins to estimate an entire family of returns to education at different quantiles of the conditional distribution of wages while addressing simultaneity and measurement error biases. We test whether there is individual heterogeneity in returns to education and find that: more able individuals obtain more schooling and that higher ability individuals (those further to the right in the conditional distribution of wages) have higher returns to schooling consistent with a non-trivial interaction between schooling and unobserved abilities in the generation of earnings. The estimated returns are never lower than 9 percent and can be as high as 13 percent at the top of the conditional distribution of wages but they vary significantly only along the lower to middle quantiles. Our findings may have meaningful implications for the design of educational policies

    Unexpectedly rapid evolution of mandibular shape in hominins

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    Members of the hominins – namely the so-called β€˜australopiths’ and the species of the genus Homo – are known to possess short and deep mandibles and relatively small incisors and canines. It is commonly assumed that this suite of traits evolved in early members of the clade in response to changing environmental conditions and increased consumption of though food items. With the emergence of Homo, the functional meaning of mandible shape variation is thought to have been weakened by technological advancements and (later) by the control over fire. In contrast to this expectation, we found that mandible shape evolution in hominins is exceptionally rapid as compared to any other primate clade, and that the direction and rate of shape change (from the ape ancestor) are no different between the australopiths and Homo. We deem several factors including the loss of honing complex, canine reduction, and the acquisition of different diets may have concurred in producing such surprisingly high evolutionary rates. This study reveals the evolution of mandibular shape in hominins has strong morpho-functional and ecological significance attached

    Evaluation of preoperative intra-aortic balloon pump in coronary patients with severe left ventricular dysfunction undergoing OPCAB surgery: early and mid-term outcomes

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    <p>Abstract</p> <p>Background</p> <p>The purpose of the present study was to evaluate the safety and the cost-effectiveness of using preoperative IABP as support compared with postoperative IABP treatment in coronary patients with severe left ventricular dysfunction (SLVD) who is undergoing off-pump coronary artery bypass surgery (OPCAB), including early outcomes, hospital mortality and morbidity, and mid-term follow-up outcomes.</p> <p>Methods</p> <p>Between March 2000 and December 2008, we prospectively and randomly studied the insertion of preoperative IABP in 115 (7.4%) and postoperative IABP in 106 (6.8%) of the 1560 consecutive patients. Group A is preoperative IABP therapy. Group B is postoperative IABP therapy.</p> <p>Results</p> <p>There was no significant difference in the number of grafts used between the two groups. Completeness of revascularization did not differ between the two groups. The statistically significant difference was hospital mortality (2.6% in group A vs. 3.8% in group B) (<it>p </it>< 0.05). And there was significant reduction in postoperative low cardiac output, malignant arrhythmia, acute renal failure and length of stay in ICU in group A, compared with group B (<it>p </it>< 0.05). In the two groups, six-, 12-, 24- and 48-month survival rates were similar. In the study the degree of improvement in angina and quality of life did not differ significantly between the two groups.</p> <p>Conclusion</p> <p>The use of preoperative IABP in SLVD patients undergoing OPCAB is of safety and effectiveness. The combined use of preoperative IABP and OPCAB allows complete revascularization in SLVD patients with an important reduction in operative mortality and excellent mid-term results.</p

    Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle

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    Background Domestication of the now-extinct wild aurochs, Bos primigenius, gave rise to the two major domestic extant cattle taxa, B. taurus and B. indicus. While previous genetic studies have shed some light on the evolutionary relationships between European aurochs and modern cattle, important questions remain unanswered, including the phylogenetic status of aurochs, whether gene flow from aurochs into early domestic populations occurred, and which genomic regions were subject to selection processes during and after domestication. Here, we address these questions using whole-genome sequencing data generated from an approximately 6,750-year-old British aurochs bone and genome sequence data from 81 additional cattle plus genome-wide single nucleotide polymorphism data from a diverse panel of 1,225 modern animals. Results Phylogenomic analyses place the aurochs as a distinct outgroup to the domestic B. taurus lineage, supporting the predominant Near Eastern origin of European cattle. Conversely, traditional British and Irish breeds share more genetic variants with this aurochs specimen than other European populations, supporting localized gene flow from aurochs into the ancestors of modern British and Irish cattle, perhaps through purposeful restocking by early herders in Britain. Finally, the functions of genes showing evidence for positive selection in B. taurus are enriched for neurobiology, growth, metabolism and immunobiology, suggesting that these biological processes have been important in the domestication of cattle. Conclusions This work provides important new information regarding the origins and functional evolution of modern cattle, revealing that the interface between early European domestic populations and wild aurochs was significantly more complex than previously thought
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