50 research outputs found

    Polar Phase Screens: A Comparison with Other Methods of Random Phase Screen Generation

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    This research provides the first organized comparison of random phase screen generation methods, including logarithmic polar Fourier series, using structure functions. Random phase screens are essential elements of simulating light propagation through turbulent media. In order to be effective, they must accurately reflect theory and be practical to implement. This research explains and evaluates three methods of generating random phase screens: using a Fourier series upon a polar frequency grid with logarithmic spacing; using the fast Fourier transform, with its Cartesian frequency grid; and using Zernike polynomials. It provides a comparison of the Polar Fourier Series technique with the two more common techniques (Fast Fourier Transform and Zernike), with the end result of giving the users enough information to choose which method best fits their needs. The evaluation criteria used are generation time (usability) and phase structure function (accuracy)

    Chorioamnionitis: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

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    Chorioamnionitis is a term encompassing a broad spectrum of disease during pregnancy that is characterized by inflammation and/or infection of intrauterine structures such as the placenta, the chorion and amnion. The clinical presentation of chorioamnionitis can vary based on clinical, microbiologic, and histologic factors which interact and overlap to varying degrees

    Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants

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    Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Peer reviewe

    Germline variation at 8q24 and prostate cancer risk in men of European ancestry

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    Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10−15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62–4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification

    Comparison of Simulium jenningsi (Diptera: Simuliidae) Larval Gut Contents across Instars

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    Black fly larvae (Diptera: Simuliidae) are a widely distributed and oftentimes dominant consumer in lotic ecosystems. However, detailed information on the composition of their diet across instars is lacking. Knowledge of their diet is important in order to understand their ecological significance as well as advance sustainable management efforts. For instance, differential instar susceptibility to Bacillus thuringiensis var. israelensis (Bti), the primary larvicide used to suppress pestiferous adult populations, has been identified. Further, current science suggests that larval diet, particularly diatoms, may contribute to impaired Bti effectiveness. Therefore, we examined gut diatom density, species composition, diversity, morphology, and ecological guilds across larval instars of Simulium jenningsi, the target species of management programs. Larval collections were made in conjunction with the Pennsylvania Department of Environmental Protection Black Fly Suppression Program from lotic systems primarily within the Susquehanna River basin (n= 14). We measured collected larvae and assigned them to size (instar) categories. Intact larvae were then subjected to a chemical digestion procedure yielding “cleaned” diatoms. A minimum of 300 diatom valves were identified to species and enumerated. Diatom community metrics were compared among instars and between geographic regions using ANOVA. A total of 134 diatom sp. were recovered from Simulium gut analyses. Preliminary results for community metrics will be discussed. Our work here provides a practical technique for detailed examination of Simulium larval gut contents across instars, ecological and spatial information on diatom consumption, and insight into a potentially important variable affecting Bti efficacy and population management of black flies in the commonwealth

    Molecular and morphological characterisation of Echinococcus from food producing animals in India

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    In view of the medical, veterinary and economic importance of hydatid disease in India, our study aimed to determine the prevalence and genotypes of Echinococcus present in domestic livestock in India. Out of 21,861 animals examined, cattle were found with the highest prevalence of hydatid cysts (5.10%) followed by buffaloes (3.81%), pigs (0.87%) and sheep (0.075%). Phylogenetic analysis of the cytochrome oxidase-1 gene revealed that the buffalo strain or G3 genotype was the predominant genotype (29/46) in all species of livestock followed by the cattle strain or G5 genotype (9/46), the G1 genotype or the common sheep strain (6/46) and the G2 genotype or Tasmanian Sheep strain (2/46). The ability of the G3 (buffalo) and G5 (cattle) genotypes of Echinococcus granulosus to infect and produce fertile hydatid cysts in pigs was also demonstrated for the first time. Both morphological and molecular results support earlier studies suggesting that Echinococcus of buffalo origin is phenotypically and genetically similar to the sheep (G1) and Tasmanian Sheep (G2) strains of Echinococcus, which adds further evidence to support its recognition as one species, viz., E. granulosus sensu stricto. Our molecular, morphological and biological characteristics also support earlier studies suggesting that Echinococcus of cattle origin, designated the G5 genotype, should be recognised as a separate species, viz. Echinococcus ortleppi. Finally, the study reveals that the prevalence of hydatidosis in urban centres in India has been showing a consistently declining trend over the past few decades, possibly owing to economic development and improved government legislation of abattoirs

    Metabolic cost adaptations during training with a soft exosuit assisting the hip joint.

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    Different adaptation rates have been reported in studies involving ankle exoskeletons designed to reduce the metabolic cost of their wearers. This work aimed to investigate energetic adaptations occurring over multiple training sessions, while walking with a soft exosuit assisting the hip joint. The participants attended five training sessions within 20 days. They walked carrying a load of 20.4 kg for 20 minutes with the exosuit powered and five minutes with the exosuit unpowered. Percentage change in net metabolic cost between the powered and unpowered conditions improved across sessions from -6.2 ± 3.9% (session one) to -10.3 ± 4.7% (session five), indicating a significant effect associated with training. The percentage change at session three (-10.5 ± 4.5%) was similar to the percentage change at session five, indicating that two 20-minute sessions may be sufficient for users to fully adapt and maximize the metabolic benefit provided by the exoskeleton. Retention was also tested measuring the metabolic reduction five months after the last training session. The percent change in metabolic cost during this session (-10.1 ± 3.2%) was similar to the last training session, indicating that the adaptations resulting in reduced metabolic cost are preserved. These outcomes are relevant when evaluating exoskeletons\u27 performance on naïve users, with a specific focus on hip extension assistance
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