14,696 research outputs found

    Item Response Modeling of Multivariate Count Data With Zero Inflation, Maximum Inflation, and Heaping

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    Questionnaires that include items eliciting count responses are becoming increasingly common in psychology. This study proposes methodological techniques to overcome some of the challenges associated with analyzing multivariate item response data that exhibit zero inflation, maximum inflation, and heaping at preferred digits. The modeling framework combines approaches from three literatures: item response theory (IRT) models for multivariate count data, latent variable models for heaping and extreme responding, and mixture IRT models. Data from the Behavioral Risk Factor Surveillance System are used as a motivating example. Practical implications are discussed, and recommendations are provided for researchers who may wish to use count items on questionnaires

    Early estimates of seasonal influenza vaccine effectiveness in Europe: results from the I-MOVE multicentre case-control study, 2012/13

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    Baltazar Nunes: member of the I-MOVE case–control study teamWe conducted a test-negative case–control study based in five European sentinel surveillance networks. The early 2012/13 adjusted influenza vaccine effectiveness was 78.2% (95% CI: 18.0 to 94.2) against influenza B, 62.1% (95% CI: −22.9 to 88.3%) against A(H1)pdm09, 41.9 (95% CI: −67.1 to 79.8) against A(H3N2) and 50.4% (95% CI: −20.7 to 79.6) against all influenza types in the target groups for vaccination. Efforts to improve influenza vaccines should continue to better protect those at risk of severe illness or complications

    Growth Rate of Stony Corals of Broward County, Florida: Effects from Past Beach Renourishment Projects

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    The skeletal growth of hermatypic (reef-building) corals is a sensitive indicator of environmental conditions and perturbations. In particular, excessive sedimentation and turbidity act to depress coral growth because energy expenditure is required to remove sediment and because turbidity reduces light energy necessary for coral health and nutrition. Normalized annual growth (linear skeletal extension) rates of Broward County, Florida reef-building corals were over 16 years (1985-1970). Star corals (Montastrea annularis) and brain corals (Diploria labyrinthiformis) were collected from each of four reef sites at two depths (9m and 18m). Collection areas were located in the vicinity of possible adverse sedimentation/turbidity effects from one or more of six past beach renourishment projects. Coral growth differences among sites at particular years and among years within sites were statistically evaluated. Years tested included those of and subsequent to each of six past beach renourishment projects. The results are suggestive that, in general, Broward County beach renourishment projects have had minor or no influence on currently living off-shore corals. However, following the Hollywood-Hallandale renourishment project of 1979, D. labyrinthiformis from the Hollywood 18m site exhibited significantly lower normalized growth compared to other sites. This may not represent effects from the renourishment project. At the Hollywood site M. annularis from both 9m and 18m and D. labyrinthiformis from 9m did not exhibit significantly lowered growth in comparison to other sites. Site averages of absolute coral growth indicated that southern 9m specimens had higher rates of growth than northern counterparts for M. annularis. In the southern collection sites, 9m growth of both species tended to be greater than 18m growth. Correlation analysis indicated that the time pattern of coral growth is similar among sites, species, and depths. Comparison of time series of coral growth data to recorded environmental variables (temperature and salinity) revealed a positive relation with salinity (water density) variations

    Software Considerations for Subscale Flight Testing of Experimental Control Laws

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    The NASA AirSTAR system has been designed to address the challenges associated with safe and efficient subscale flight testing of research control laws in adverse flight conditions. In this paper, software elements of this system are described, with an emphasis on components which allow for rapid prototyping and deployment of aircraft control laws. Through model-based design and automatic coding a common code-base is used for desktop analysis, piloted simulation and real-time flight control. The flight control system provides the ability to rapidly integrate and test multiple research control laws and to emulate component or sensor failures. Integrated integrity monitoring systems provide aircraft structural load protection, isolate the system from control algorithm failures, and monitor the health of telemetry streams. Finally, issues associated with software configuration management and code modularity are briefly discussed

    Outbreak of Marburg hemorrhagic fever among miners in Kamwenge and Ibanda Districts, Uganda, 2007

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    Marburg hemorrhagic fever was detected among 4 miners in Ibanda District, Uganda, from June through September, 2007. Infection was likely acquired through exposure to bats or bat secretions in a mine in Kamwenge District, Uganda, and possibly human-to-human transmission between some patients. We describe the epidemiologic investigation and the health education response

    Early estimates of seasonal influenza vaccine effectiveness in Europe among target groups for vaccination: results from the I-MOVE multicentre case-control study, 2011/12

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    Colaboração de: Baltazar Nunes, investigador do DEPTo provide an early estimate of 2011/12 influenza vaccine effectiveness (VE), we conducted a multicentre case–control study based on seven sentinel surveillance networks. We included influenza-like illness cases up to week 7/2012 from the vaccination target groups, swabbed less than eight days after symptom onset. Laboratory-confirmed influenza A(H3) cases were compared to negative controls. Adjusted VE was 43% (95% confidence interval: -0.4 to 67.7), suggesting low to moderate VE against influenza A(H3) in the early 2011/12 season

    Developing and testing accelerated partner therapy for partner notification for people with genital Chlamydia trachomatis diagnosed in primary care: a pilot randomised controlled trial

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    Background Accelerated partner therapy (APT) is a promising partner notification (PN) intervention in specialist sexual health clinic attenders. To address its applicability in primary care, we undertook a pilot randomised controlled trial (RCT) of two APT models in community settings. Methods Three-arm pilot RCT of two adjunct APT interventions: APTHotline (telephone assessment of partner(s) plus standard PN) and APTPharmacy (community pharmacist assessment of partner(s) plus routine PN), versus standard PN alone (patient referral). Index patients were women diagnosed with genital chlamydia in 12 general practices and three community contraception and sexual health (CASH) services in London and south coast of England, randomised between 1 September 2011 and 31 July 2013. Results 199 women described 339 male partners, of whom 313 were reported by the index as contactable. The proportions of contactable partners considered treated within 6 weeks of index diagnosis were APTHotline 39/111 (35%), APTPharmacy 46/100 (46%), standard patient referral 46/102 (45%). Among treated partners, 8/39 (21%) in APTHotline arm were treated via hotline and 14/46 (30%) in APTPharmacy arm were treated via pharmacy. Conclusions The two novel primary care APT models were acceptable, feasible, compliant with regulations and capable of achieving acceptable outcomes within a pilot RCT but intervention uptake was low. Although addition of these interventions to standard PN did not result in a difference between arms, overall PN uptake was higher than previously reported in similar settings, probably as a result of introducing a formal evaluation. Recruitment to an individually randomised trial proved challenging and full evaluation will likely require service-level randomisation

    Sino-Soviet relations, 1964-1965

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    "Prepared for the Conference on Sino-Soviet Relations and Arms Control sponsored by Harvard University under contract with the Arms Control and Disarmament Agency, Airlie House, Warrenton, Virginia, August 30-September 4, 1965.""1596"--handwritten on coverIncludes bibliographical reference

    Evaluation and use of surveillance system data toward the identification of high-risk areas for potential cholera vaccination: a case study from Niger.

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    In 2008, Africa accounted for 94% of the cholera cases reported worldwide. Although the World Health Organization currently recommends the oral cholera vaccine in endemic areas for high-risk populations, its use in Sub-Saharan Africa has been limited. Here, we provide the principal results of an evaluation of the cholera surveillance system in the region of Maradi in Niger and an analysis of its data towards identifying high-risk areas for cholera

    Substitutions near the hemagglutinin receptor-binding site determine the antigenic evolution of influenza A H3N2 viruses in U.S. swine

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    Swine influenza A virus is an endemic and economically important pathogen in pigs, with the potential to infect other host species. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major component in swine influenza A vaccines. However, as a result of antigenic drift, vaccine strains must be regularly updated to reflect currently circulating strains. Characterizing the cross-reactivity between strains in pigs and seasonal influenza virus strains in humans is also important in assessing the relative risk of interspecies transmission of viruses from one host population to the other. Hemagglutination inhibition (HI) assay data for swine and human H3N2 viruses were used with antigenic cartography to quantify the antigenic differences among H3N2 viruses isolated from pigs in the United States from 1998 to 2013 and the relative cross-reactivity between these viruses and current human seasonal influenza A virus strains. Two primary antigenic clusters were found circulating in the pig population, but with enough diversity within and between the clusters to suggest updates in vaccine strains are needed. We identified single amino acid substitutions that are likely responsible for antigenic differences between the two primary antigenic clusters and between each antigenic cluster and outliers. The antigenic distance between current seasonal influenza virus H3 strains in humans and those endemic in swine suggests that population immunity may not prevent the introduction of human viruses into pigs, and possibly vice versa, reinforcing the need to monitor and prepare for potential incursions
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