1,836 research outputs found

    Modulation of inherent dynamical tendencies of the bisabolyl cation via preorganization in epi-isozizaene synthase.

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    The relative importance of preorganization, selective transition state stabilization and inherent reactivity are assessed through quantum chemical and docking calculations for a sesquiterpene synthase (epi-isozizaene synthase, EIZS). Inherent reactivity of the bisabolyl cation, both static and dynamic, appears to determine the pathway to product, although preorganization and selective binding of the final transition state structure in the multi-step carbocation cascade that forms epi-isozizaene appear to play important roles

    The uncontrolled cooking test : measuring three-stone fire performance in northern Mozambique

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    The assessment of cooking system performance in developing countries is a continued area of interest, with laboratory testing methods often being unrepresentative of real world use, and field based methods tending to be resource intensive with high levels of variability. This paper presents the Uncontrolled Cook Test (UCT), a relatively low cost field testing protocol that assesses the task-based performance of the system when cooking any meal and operated as per local conditions and practice. A total of 29 UCTs were conducted in households in a study village in rural northern Mozambique, all on wood-burning three stone fires. The UCT proved a capable method for the assessment of cooking system performance and, critically, returned a data set with less variation than is typically reported by existing field test methods, so offering the potential to use fewer resources to detect a statistically significant difference between baseline and ‘improved’ stove results

    Response to Intervention and the Impact on Eligibility for Special Education Services in Texas

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    Response to Intervention (RTI) trends and special education referrals were examined and compared with the self-reported data of special education directors and evaluation staff to determine the overall impact of RTI on special education referrals. A descriptive nonexperimental design study using existing data and survey methods was used. Findings from archival data demonstrated that during the period ranging from 2007 to 2011, trends at the state level, across regional services centers, and in one independent school district showed an increase in the number of students who were referred and found eligible for special education services. However, there was an average decrease in the number of students receiving special education services at the regional and state levels and an increase according to one district level. The trends that evolved suggest a possible relationship between the RTI process and increasingly accurate referrals for special education services. Findings from the survey administered at the Education Service Center (ESC) indicated the perceptions of special education directors and evaluation staff did not mirror the findings of the archival data. However, data gathered from the survey administered at the Independent School District (ISD) indicated the perceptions of the special education director and evaluation staff did mirror the findings of actual archival data

    Response of Sod-Seeded Annual Clover to Herbicide Residue

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    Last updated: 6/9/200

    Optimising the imbaula stove

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    In South Africa, human and environmental health implications from domestic solid fuel combustion have spurred interest in cleaner alternative sources of energy and better combustion technologies. Field research among wood and coal burning informal settlements in Johannesburg has shown that the most prevalent mode of combustion is self-made imbaula (brazier) stoves, manufactured from discarded 20 L steel drums. Such stoves are made without any measure of performance optimisation, leading to fuel inefficiency and high emissions - previous field surveys have indicated that the number, size and placement of primary and secondary air inlets (taken as holes below and above the fire grate respectively) vary over a wide range, starting from an extreme with no holes below the grate [1]. Researchers at SeTAR Centre, University of Johannesburg, have set out to develop an enhanced imbaula, by investigating performance in terms of size and distribution of primary and secondary air inlets, and height of grate level. The test imbaulas are constructed out of standard 20 L drums with a height of 360 mm and diameter of 295 mm. A range of hole configurations has been designed, from which selected test configurations are fabricated for experimental evaluation of thermal and emissions properties, using the SeTAR heterogeneous testing protocol. The results indicate that higher hole densities (above and below the grate) lead to higher power outputs and lower specific CO emissions, but with lower thermal efficiency. Further, results indicate that adequate air holes below the grate (primary air) are more important for proper combustion in an imbaula; however this should be synchronised with secondary air in-lets (above the grid) in order to have congruence of all the performance criteria. This study should lead to the development of a set of criteria that can further enhance emissions reductions and fuel efficiency obtained by top-down stove ignition methods (Basa njengo Magogo) for imbaula type stoves

    Establishing disability weights for congenital pediatric surgical conditions: A multi-modal approach

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    __Background:__ Burden of disease (BoD) as measured by Disability-Adjusted Life Years (DALYs) is one of the criteria for priority-setting in health care resource allocation. DALYs incorporate disability weights (DWs), which are currently expert-derived estimates or non-existent for most pediatric surgical conditions. The objective of this study is to establish DWs for a subset of key pediatric congenital anomalies using a range of health valuation metrics with caregivers in both high- and low-resource settings. __Method:__ We described 15 health states to health professionals (physicians, nurses, social workers, and therapists) and community caregivers in Kenya and Canada. The health states summaries were expert- and community-derived, consisting of a narrated description of the disease and a functional profile described in EQ-5D-5 L style. DWs for each health state were elicited using four health valuation exercises (preference ranking, visual analogue scale (VAS), paired comparison (PC), and time trade-off (TTO)). The PC data were anchored internally to the TTO and externally to existing data to yield DWs for each health state on a scale from 0 (health) to 1 (dead). Any differences in DWs between the two countries were analyzed. __Results:__ In total, 154 participants, matched by profession, were recruited from Kijabe, Kenya (n = 78) and Hamilton, Canada (n = 76). Overall calculated DWs for 15 health states ranged from 0.13 to 0.77, with little difference between countries (intra-class coefficient 0.97). However, DWs generated in Kenya for severe hypospadias and undescended testes were higher than Canadian-derived DWs (p = 0.04 and p < 0.003, respectively). __Conclusions:__ We have derived country-specific DWs for pediatric congenital anomalies using several low-cost methods and inter-professional and community caregivers. The TTO-anchored PC method appears best suited for future use. The majority of DWs do not appear to differ significantly between the two cultural contexts and could be used to inform further work of estimating the burden of global pediatric surgical disease. Care should be taken in comparing the DWs obtained in the current study to the existent list of DWs because methodological differences may impact on their compatibility

    Patient safety in dentistry: development of a candidate 'never event' list for primary care

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    Introduction The 'never event' concept is often used in secondary care and refers to an agreed list of patient safety incidents that 'should not happen if the necessary preventative measures are in place'. Such an intervention may raise awareness of patient safety issues and inform team learning and system improvements in primary care dentistry. Objective To identify and develop a candidate never event list for primary care dentistry. Methods A literature review, eight workshops with dental practitioners and a modified Delphi with 'expert' groups were used to identify and agree candidate never events. Results Two-hundred and fifty dental practitioners suggested 507 never events, reduced to 27 distinct possibilities grouped across seven themes. Most frequently occurring themes were: 'checking medical history and prescribing' (119, 23.5%) and 'infection control and decontamination' (71, 14%). 'Experts' endorsed nine candidate never event statements with one graded as 'extreme risk' (failure to check past medical history) and four as 'high risk' (for example, extracting wrong tooth). Conclusion Consensus on a preliminary list of never events was developed. This is the first known attempt to develop this approach and an important step in determining its value to patient safety. Further work is necessary to develop the utility of this method

    RAD-sequencing for estimating GRM-based heritability in the wild:a case study in roe deer

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    International audienceEstimating the evolutionary potential of quantitative traits and reliably predicting responses to selection in wild populations are important challenges in evolutionary biology. The genomic revolution has opened up opportunities for measuring relatedness among individuals with precision, enabling pedigree‐free estimation of trait heritabilities in wild populations. However, until now, most quantitative genetic studies based on a genomic relatedness matrix (GRM) have focused on long‐term monitored populations for which traditional pedigrees were also available, and have often had access to knowledge of genome sequence and variability. Here, we investigated the potential of RAD‐sequencing for estimating heritability in a free‐ranging roe deer (Capreolous capreolus) population for which no prior genomic resources were available. We propose a step‐by‐step analytical framework to optimize the quality and quantity of the genomic data and explore the impact of the single nucleotide polymorphism (SNP) calling and filtering processes on the GRM structure and GRMbased heritability estimates. As expected, our results show that sequence coverage strongly affects the number of recovered loci, the genotyping error rate and the amount of missing data. Ultimately, this had little effect on heritability estimates and their standard errors, provided that the GRM was built from a minimum number of loci (above 7,000). Genomic relatedness matrix‐based heritability estimates thus appear robust to a moderate level of genotyping errors in the SNP data set. We also showed that quality filters, such as the removal of low‐frequency variants, affect the relatedness structure of the GRM, generating lower h2 estimates. Our work illustrates the huge potential of RAD‐sequencing for estimating GRM‐based heritability in virtually any natural population
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