291 research outputs found

    Preliminary calibration and test results from the National Transonic Facility

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    The National Transonic Facility (NTF) was operated to design condition of 120 million Reynolds number at a Mach number of 1.0. All systems were checked out except plenum isolation valves; modifications are being made to heaters on the actuators. Initial steady-state calibration indicates excellent steady flow characteristics. The first test of the Pathfinder 1 model indicated significant Reynolds number effects. Some effect of temperature on instrumentation were obtained. The cause of these effects is being evaluated

    Latitudinal dependency of geomagnetic polarity transition durations

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    Palaeomagnetic records of the Matuyama-Brunhes polarity transition were obtained from seven, low sedimentation rate, deepsea cores from the Pacific Ocean. The cores were taken near the 180° meridian and provide a latitudinal transect of transition records extending from 45.3° N to 33.4° S. Examination of these records suggests that low sedimentation rate cores may not be capable of recording the fine details of transitional field behaviour, but there are indications that these cores may, in fact, provide accurate records of the more general features of the reversal. Most notable of these features is that the duration of the transition is dependent on the site latitude, with durations at mid-latitudes being more than a factor of 2 longer than at equatorial latitudes

    A prevalence of dynamo-generated magnetic fields in the cores of intermediate-mass stars

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    Magnetic fields play a part in almost all stages of stellar evolution. Most low-mass stars, including the Sun, show surface fields that are generated by dynamo processes in their convective envelopes. Intermediate-mass stars do not have deep convective envelopes, although 10 per cent exhibit strong surface fields that are presumed to be residuals from the star formation process. These stars do have convective cores that might produce internal magnetic fields, and these fields might survive into later stages of stellar evolution, but information has been limited by our inability to measure the fields below the stellar surface. Here we report the strength of dipolar oscillation modes for a sample of 3,600 red giant stars. About 20 per cent of our sample show mode suppression, by strong magnetic fields in the cores, but this fraction is a strong function of mass. Strong core fields occur only in red giants heavier than 1.1 solar masses, and the occurrence rate is at least 50 per cent for intermediate-mass stars (1.6–2.0 solar masses), indicating that powerful dynamos were very common in the previously convective cores of these stars

    Neurobehavioral consequences of chronic intrauterine opioid exposure in infants and preschool children: a systematic review and meta-analysis

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    <b>Background</b><p></p> It is assumed within the accumulated literature that children born of pregnant opioid dependent mothers have impaired neurobehavioral function as a consequence of chronic intrauterine opioid use.<p></p> <b>Methods</b><p></p> Quantitative and systematic review of the literature on the consequences of chronic maternal opioid use during pregnancy on neurobehavioral function of children was conducted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched Cinahl, EMBASE, PsychINFO and MEDLINE between the periods of January 1995 to January 2012.<p></p> <b>Results</b><p></p> There were only 5 studies out of the 200 identified that quantitatively reported on neurobehavioral function of children after maternal opioid use during pregnancy. All 5 were case control studies with the number of exposed subjects within the studies ranging from 33–143 and 45–85 for the controls. This meta-analysis showed no significant impairments, at a non-conservative significance level of p < 0.05, for cognitive, psychomotor or observed behavioural outcomes for chronic intra-uterine exposed infants and pre-school children compared to non-exposed infants and children. However, all domains suggested a trend to poor outcomes in infants/children of opioid using mothers. The magnitude of all possible effects was small according to Cohen’s benchmark criteria.<p></p> <b>Conclusions</b><p></p> Chronic intra-uterine opioid exposed infants and pre-school children experienced no significant impairment in neurobehavioral outcomes when compared to non-exposed peers, although in all domains there was a trend to poorer outcomes. The findings of this review are limited by the small number of studies analysed, the heterogenous populations and small numbers within the individual studies. Longitudinal studies are needed to determine if any neuropsychological impairments appear after the age of 5 years and to help investigate further the role of environmental risk factors on the effect of ‘core’ phenotypes

    Eigengene networks for studying the relationships between co-expression modules

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    <p>Abstract</p> <p>Background</p> <p>There is evidence that genes and their protein products are organized into functional modules according to cellular processes and pathways. Gene co-expression networks have been used to describe the relationships between gene transcripts. Ample literature exists on how to detect biologically meaningful modules in networks but there is a need for methods that allow one to study the relationships between modules.</p> <p>Results</p> <p>We show that network methods can also be used to describe the relationships between co-expression modules and present the following methodology. First, we describe several methods for detecting modules that are shared by two or more networks (referred to as consensus modules). We represent the gene expression profiles of each module by an eigengene. Second, we propose a method for constructing an eigengene network, where the edges are undirected but maintain information on the sign of the co-expression information. Third, we propose methods for differential eigengene network analysis that allow one to assess the preservation of network properties across different data sets. We illustrate the value of eigengene networks in studying the relationships between consensus modules in human and chimpanzee brains; the relationships between consensus modules in brain, muscle, liver, and adipose mouse tissues; and the relationships between male-female mouse consensus modules and clinical traits. In some applications, we find that module eigengenes can be organized into higher level clusters which we refer to as meta-modules.</p> <p>Conclusion</p> <p>Eigengene networks can be effective and biologically meaningful tools for studying the relationships between modules of a gene co-expression network. The proposed methods may reveal a higher order organization of the transcriptome. R software tutorials, the data, and supplementary material can be found at the following webpage: <url>http://www.genetics.ucla.edu/labs/horvath/CoexpressionNetwork/EigengeneNetwork</url>.</p

    Regenerative grazing for climate, ecosystem, and human health

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    The brief is about the case study of two transformative land regeneration approaches developed in Africa: agroforestry and regenerative grazing management. These two approaches come together in silvopastoral systems - livestock grazing and browsing in tree-dotted grasslands - which have been ranked among the most effective carbon drawdown tools at our disposal. This was presented in COP27 in Sharm El-Sheikh, Egypt venue

    Weighted gene coexpression network analysis strategies applied to mouse weight

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    Systems-oriented genetic approaches that incorporate gene expression and genotype data are valuable in the quest for genetic regulatory loci underlying complex traits. Gene coexpression network analysis lends itself to identification of entire groups of differentially regulated genes—a highly relevant endeavor in finding the underpinnings of complex traits that are, by definition, polygenic in nature. Here we describe one such approach based on liver gene expression and genotype data from an F2 mouse intercross utilizing weighted gene coexpression network analysis (WGCNA) of gene expression data to identify physiologically relevant modules. We describe two strategies: single-network analysis and differential network analysis. Single-network analysis reveals the presence of a physiologically interesting module that can be found in two distinct mouse crosses. Module quantitative trait loci (mQTLs) that perturb this module were discovered. In addition, we report a list of genetic drivers for this module. Differential network analysis reveals differences in connectivity and module structure between two networks based on the liver expression data of lean and obese mice. Functional annotation of these genes suggests a biological pathway involving epidermal growth factor (EGF). Our results demonstrate the utility of WGCNA in identifying genetic drivers and in finding genetic pathways represented by gene modules. These examples provide evidence that integration of network properties may well help chart the path across the gene–trait chasm

    Adoption of practice guidelines and assessment tools in substance abuse treatment

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    <p>Abstract</p> <p>Background</p> <p>The gap between research and practice limits utilization of relevant, progressive and empirically validated strategies in substance abuse treatment.</p> <p>Methods</p> <p>Participants included substance abuse treatment programs from the Northeastern United States. Structural equation models were constructed with agency level data to explore two outcome variables: adoption of practice guidelines and assessment tools at two points in time; models also included organizational, staffing and service variables.</p> <p>Results</p> <p>In 1997, managed care involvement and provision of primary care services had the strongest association with increased use of assessment tools, which, along with provision of counseling services, were associated with a greater use of practice guidelines. In 2001, managed care involvement, counseling services and being a stand-alone drug treatment agency were associated with a greater use of assessment tools, which was in turn related to an increase in the use of practice guidelines.</p> <p>Conclusions</p> <p>This study provides managers, clinicians and policy-makers with a framework for understanding factors related to the adoption of new technologies in substance abuse treatment.</p
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