5,303 research outputs found

    Prediction of VO\u3csub\u3e2\u3c/sub\u3e Peak Using Sub-Maximum Bench Step Test in Children

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    The purpose of this study was to develop a valid prediction of maximal oxygen uptake from data collected during a submaximum bench stepping test among children ages 8-12 years. Twentyseven active subjects (16 male and 11 female), weight 36.1 kg, height 144.4 cm and VO2 47.4 ± 7.9 ml/kg/min participated. Subjects completed a maximal oxygen consumption test with analysis of expired air and a submaximal bench stepping test. A formula to predict VO2max was developed from height, resting heart rate and heart rate response during the submaximum bench stepping test. This formula accounted for 71% of the variability in maximal oxygen consumption and is the first step in verifying the validity of the submaximum bench stepping test to predict VO2max. VO2max = -2.354 + (Height in cm * 0.065) + (Resting Heart Rate * 0.008) + (Step Test Average Heart Rate as a Percentage of Resting Heart Rate * -0.870

    Distance Education and Technology Infrastructure: Strategies and Opportunities

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    Distance education provides a wealth of opportunities and areas for innovation, but it also presents unique challenges for implementation and eventual success. To mitigate these challenges, this chapter will present four critical components—systems, objectives, evaluation, and personnel—that combine into one to create a technology infrastructure that can support distance delivery. Through this chapter, e-learning leaders will gain the knowledge to not only identify key features of tools used for distance delivery, but also understand and appreciate the correlation between a holistic infrastructure approach and quality distance delivery. The absence of one of these critical components will likely result in an unsuccessful technology integration. To aid in the explanation of these critical components, the chapter will focus on three main distance education delivery forms—webinars, classroom captures, and e-learning modules. The chapter will provide an overview of the types of questions and elements that should go into consideration of any distance education tool, and will aid in the effective assessment and evaluation of these tools, as well as personnel considerations that should be taken into account

    Does KIPP Grow Advantaged? Analyzing KIPP Campuses Over Time

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    Knowledge Is Power Program (KIPP) charter schools are regarded as among the most academically successful schools serving high poverty populations. KIPP schools serve students that are more likely to be poor and from racial minorities than their peers in nearby traditional public schools. Nevertheless, it is possible that, as parents become aware of KIPP’s seemingly successful track record, the student population at KIPP might become less disadvantaged over time. Using Common Core data, we examined demographic changes in 81 KIPP schools that opened between 1995 and 2011, finding no quantitative evidence that KIPP students are growing more advantaged over time. Interviews with KIPP leaders suggest that such stability may reflect purposeful marketing aimed at attracting the most disadvantaged students, though more research is needed

    Modeling soil organic carbon change in croplands of China

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    Using 1990 conditions, we modeled carbon (C) and nitrogen (N) biogeochemical cycles in croplands of China (and, for comparison, the United States) to estimate the annual soil organic-carbon (SOC) balance for all cropland. Overall, we estimate that China\u27s croplands lost 1.6% of their SOC (to a depth of 0.3 m) in 1990, and that U.S. cropland lost 0.1%. A key element in this difference was that ∌25% of aboveground crop residue in China was returned to the soil, compared to ∌90% in the United States. In China, SOC losses were greatest in the northeast (∌103 kg C·ha–1·yr–1), and were generally smaller (\u3c0.5 × 103 kg C·ha–1·yr–1) in regions with a longer cultivation history. Some regions showed SOC gains, generally \u3c103 kg C·ha–1·yr–1. Reduced organic-matter input to China\u27s cropland soils, and lower overall SOC levels in those soils, led to lower levels of N mineralization in the simulations, consistent with higher rates of synthetic-fertilizer application in China. C and N cycles are closely linked to soil fertility, crop yield, and non-point-source environmental pollution

    An experimental hut study to quantify the effect of DDT and airborne pyrethroids on entomological parameters of malaria transmission

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    <b>Background</b><p></p> Current malaria vector control programmes rely on insecticides with rapid contact toxicity. However, spatial repellents can also be applied to reduce man-vector contact, which might ultimately impact malaria transmission. The aim of this study was to quantify effects of airborne pyrethroids from coils and DDT used an indoor residual spray (IRS) on entomological parameters that influence malaria transmission.<p></p> <b>Methods</b><p></p> The effect of Transfluthrin and Metofluthrin coils compared to DDT on house entry, exit and indoor feeding behaviour of Anopheles gambiae sensu lato were measured in experimental huts in the field and in the semi-field. Outcomes were deterrence - reduction in house entry of mosquitoes; irritancy or excito-repellency – induced premature exit of mosquitoes; blood feeding inhibition and effect on mosquito fecundity.<p></p> <b>Results</b><p></p> Transfluthrin coils, Metofluthrin coils and DDT reduced human vector contact through deterrence by 38%, 30% and 8%, respectively and induced half of the mosquitoes to leave huts before feeding (56%, 55% and 48%, respectively). Almost all mosquitoes inside huts with Metofluthrin and Transfluthrin coils and more than three quarters of mosquitoes in the DDT hut did not feed, almost none laid eggs and 67%, 72% and 70% of all mosquitoes collected from Transfluthrin, Metofluthrin and DDT huts, respectively had died after 24 hours.<p></p> <b>Conclusion</b><p></p> This study highlights that airborne pyrethroids and DDT affect a range of anopheline mosquito behaviours that are important parameters in malaria transmission, namely deterrence, irritancy/excito-repellency and blood-feeding inhibition. These effects are in addition to significant toxicity and reduced mosquito fecundity that affect mosquito densities and, therefore, provide community protection against diseases for both users and non-users. Airborne insecticides and freshly applied DDT had similar effects on deterrence, irritancy and feeding inhibition. Therefore, it is suggested that airborne pyrethroids, if delivered in suitable formats, may complement existing mainstream vector control tools

    The Old Bailey proceedings and the representation of crime and criminal justice in eighteenth-century London

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    The Proceedings of the Old Bailey, published accounts of felony trials held at London’s central criminal court, were a remarkable publishing phenomenon. First published in 1674, they quickly became a regular periodical, with editions published eight times a year following each session of the court. Despite the huge number of trial reports (some 50,000 in the eighteenth century), the Proceedings, also known as the “Sessions Papers”, have formed the basis of several important studies in social history, dating back to Dorothy George’s seminal London Life in the Eighteenth Century (1925). Their recent publication online, however, has not only made them more widely available, but also changed the way historians consult them, leading to greater use of both quantitative analysis, using the statistics function, and qualitative examination of their language, through keyword searching. In the context of recent renewed interest in the history of crime and criminal justice, for which this is the most important source available in this period, the growing use of the Proceedings raises questions about their reliability, and, by extension, the motivations for their original publication. Historians generally consider the Proceedings to present accurate, if often incomplete, accounts of courtroom proceedings. From this source, along with manuscript judicial records, criminal biographies (including the Ordinary’s Accounts), polemical pamphlets such as Henry Fielding’s Enquiry into the Causes of the Late Increase of Robbers (1751), and of course the satirical prints of William Hogarth, they have constructed a picture of eighteenth-century London as a city overwhelmed by periodic crime waves and of a policing and judicial system which was forced into wide-ranging reforms in order to meet this challenge

    Survival Rates Indicate that Correlations Between Community-Weighted Mean Traits and Environments can be Unreliable Estimates of the Adaptive Value of Traits

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    Correlations between community-weighted mean (CWM) traits and environmental gradients are often assumed to quantify the adaptive value of traits. We tested this assumption by comparing these correlations with models of survival probability using 46 perennial species from long-term permanent plots in pine forests of Arizona. Survival was modeled as a function of trait-by-environment interactions, plant size, climatic variation, and neighborhood competition. The effect of traits on survival depended on the environmental conditions, but the two statistical approaches were inconsistent. For example, CWM specific leaf area (SLA) and soil fertility were uncorrelated. However, survival was highest for species with low SLA in infertile soil, a result which agreed with expectations derived from the physiological tradeoff underpinning leaf economic theory. CWM trait-environment relationships were unreliable estimates of how traits affected survival, and should only be used in predictive models when there is empirical support for an evolutionary tradeoff that affects vital rates
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