213 research outputs found

    US and foreign alloy cross-reference database

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    Marshall Space Flight Center and other NASA installations have a continuing requirement for materials data from other countries involved with the development of joint international Spacelab experiments and other hardware. This need includes collecting data for common alloys to ascertain composition, physical properties, specifications, and designations. This data is scattered throughout a large number of specification statements, standards, handbooks, and other technical literature which make a manual search both tedious and often limited in extent. In recognition of this problem, a computerized database of information on alloys was developed along with the software necessary to provide the desired functions to access this data. The intention was to produce an initial database covering aluminum alloys, along with the program to provide a user-interface to the data, and then later to extend and refine the database to include other nonferrous and ferrous alloys

    Attitudes and Beliefs of Marriage and Family Therapists Regarding Psychotropic Drugs and Therapy

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    Clinical members of AAMFT were solicited by means of a randomized multi-staged clustering technique to identify their attitudes and beliefs regarding psychotropic drugs. All participants were blind to the overall purpose of the study (n = 322) and were directed to read a clinical vignette and then identify what course of action they would take with the client. They were then asked to complete a small questionnaire regarding their attitudes and beliefs regarding psychotropic drugs. Results of the study showed that 35.7% of the clinicians identified medication and a medication referral as a viable treatment option they might pursue with a client meeting criteria for major depressive episode. Clinicians who reported having a dedicated university class (17.2%) in psychopharmacology were more likely to identify medication referral as a treatment option. However, 80% of the AAMFT clinicians we surveyed reported that they were not adequately trained about psychotropic medications in their graduate programs. Further implications regarding diagnostic practices are also discussed, as 26% of clinicians failed to explicitly diagnose the client in the case vignette with depression

    Social support, physical activity and sedentary behavior among 6(th)-grade girls: a cross-sectional study

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    BACKGROUND: Despite the importance of social support in promoting physical activity, little is known about the relative influence of the type or source of social support on adolescent girls' physical activity and sedentary behaviors. This study examined the associations of two types of social support (social participation in and social encouragement for physical activity) and two social support sources (family and friends) with self-reported daily minutes of physical activity and sedentary behavior among sixth-grade girls in Texas. METHODS: A secondary analysis of 718 sixth-grade girls between the ages of 10 to 14 was performed using cross-sectional baseline data from an osteoporosis prevention intervention study. Physical activity and sedentary behaviors (television-video viewing and computer-video game playing) were assessed using 3 administrations of the Self-Administered Physical Activity Checklist; social support indicators were assessed with Likert-type items from a psychosocial questionnaire. RESULTS: In multiple linear regression analyses, friend physical activity participation (partial correlation coefficient (r) = 0.10, p = .009) and friend (r = 0.12) and family encouragement (r = 0.11) (p < .01, respectively) were positively related to moderate-to-vigorous physical activity in the full model with other support variables, BMI and ethnicity; friend encouragement was the only variable positively related to vigorous physical activity (r = 0.11, p = .005). Family participation in physical activity had the strongest negative correlation with total minutes of television-video viewing and computer-video playing (r = -0.08, p < .05). CONCLUSION: Findings lend support to the importance of social support for physical activity among adolescent girls but suggest that the source and type of social support may differ for physical activity and sedentary behaviors. Further research is needed to assess the causal or reciprocal relation between the roles of friends and family in promoting physical activity and of family physical activity in decreasing sedentary behaviors among early adolescent girls

    Variation in DNA methylation patterns is more common among maize inbreds than among tissues

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    Chromatin modifications, such as DNA methylation, can provide heritable, epigenetic regulation of gene expression in the absence of genetic changes. A role for DNA methylation in meiotically stable marking of repetitive elements and other sequences has been demonstrated in plants. Methylation of DNA is also proposed to play a role in development through providing a mitotic memory of gene expression states established during cellular differentiation. We sought to clarify the relative levels of DNA methylation variation among different genotypes and tissues in maize (Zea mays L.). We have assessed genomewide DNA methylation patterns in leaf, immature tassel, embryo, and endosperm tissues of two inbred maize lines: B73 and Mo17. There are hundreds of regions of differential methylation present between the two genotypes. In general, the same regions exhibit differential methylation between B73 and Mo17 in each of the tissues that were surveyed. In contrast, there are few examples of tissue-specific DNA methylation variation. Only a subset of regions with tissue-specific variation in DNA methylation show similar patterns in both genotypes of maize and even fewer are associated with altered gene expression levels among the tissues. Our data indicates a limited impact of DNA methylation on developmental gene regulation within maize

    Pervasive gene content variation and copy number variation in maize and its undomesticated progenitor

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    Individuals of the same species are generally thought to have very similar genomes. However, there is growing evidence that structural variation in the form of copy number variation (CNV) and presence-absence variation (PAV) can lead to variation in the genome content of individuals within a species. Array comparative genomic hybridization (CGH) was used to compare gene content and copy number variation among 19 diverse maize inbreds and 14 genotypes of the wild ancestor of maize, teosinte. We identified 479 genes exhibiting higher copy number in some genotypes (UpCNV) and 3410 genes that have either fewer copies or are missing in the genome of at least one genotype relative to B73 (DownCNV/PAV). Many of these DownCNV/PAV are examples of genes present in B73, but missing from other genotypes. Over 70% of the CNV/PAV examples are identified in multiple genotypes, and the majority of events are observed in both maize and teosinte, suggesting that these variants predate domestication and that there is not strong selection acting against them. Many of the genes affected by CNV/PAV are either maize specific (thus possible annotation artifacts) or members of large gene families, suggesting that the gene loss can be tolerated through buffering by redundant functions encoded elsewhere in the genome. While this structural variation may not result in major qualitative variation due to genetic buffering, it may significantly contribute to quantitative variation

    Genomic distribution of H3K9me2 and DNA methylation in a maize genome

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    DNA methylation and dimethylation of lysine 9 of histone H3 (H3K9me2) are two chromatin modifications that can be associated with gene expression or recombination rate. The maize genome provides a complex landscape of interspersed genes and transposons. The genome-wide distribution of DNA methylation and H3K9me2 were investigated in seedling tissue for the maize inbred B73 and compared to patterns of these modifications observed in Arabidopsis thaliana. Most maize transposons are highly enriched for DNA methylation in CG and CHG contexts and for H3K9me2. In contrast to findings in Arabidopsis, maize CHH levels in transposons are generally low but some sub-families of transposons are enriched for CHH methylation and these families exhibit low levels of H3K9me2. The profile of modifications over genes reveals that DNA methylation and H3K9me2 is quite low near the beginning and end of genes. Although elevated CG and CHG methylation are found within gene bodies, CHH and H3K9me2 remain low. Maize has much higher levels of CHG methylation within gene bodies than observed in Arabidopsis and this is partially attributable to the presence of transposons within introns for some maize genes. These transposons are associated with high levels of CHG methylation and H3K9me2 but do not appear to prevent transcriptional elongation. Although the general trend is for a strong depletion of H3K9me2 and CHG near the transcription start site there are some putative genes that have high levels of these chromatin modifications. This study provides a clear view of the relationship between DNA methylation and H3K9me2 in the maize genome and how the distribution of these modifications is shaped by the interplay of genes and transposons.The research was supported by a grant from the National Science Foundation (IOS-1237931) to MWV and NMS. This work also used resources or cyberinfrastructure provided by iPlant Collaborative. The iPlant Collaborative is funded by a grant from the National Science Foundation (DBI-0735191; www. iplantcollaborative.org). Start-up funds from the University of Georgia and a research grant from the National Science Foundation (IOS-1339194) to RJS supported aspects of this study

    Distribution, functional impact, and origin mechanisms of copy number variation in the barley genome

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    BACKGROUND There is growing evidence for the prevalence of copy number variation (CNV) and its role in phenotypic variation in many eukaryotic species. Here we use array comparative genomic hybridization to explore the extent of this type of structural variation in domesticated barley cultivars and wild barleys. RESULTS A collection of 14 barley genotypes including eight cultivars and six wild barleys were used for comparative genomic hybridization. CNV affects 14.9% of all the sequences that were assessed. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. CNVs are enriched near the ends of all chromosomes except 4H, which exhibits the lowest frequency of CNVs. CNV affects 9.5% of the coding sequences represented on the array and the genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases. Sequence-based comparisons of CNV between cultivars Barke and Morex provided evidence that DNA repair mechanisms of double-strand breaks via single-stranded annealing and synthesis-dependent strand annealing play an important role in the origin of CNV in barley. CONCLUSIONS We present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley, and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance. We also identify potential mechanisms that can generate variation in copy number in plant genomes.This work was financially supported by the following grants: project GABI-BARLEX, German Federal Ministry of Education and Research (BMBF), #0314000 to MP, US, KFXM and NS; Triticeae Coordinated Agricultural Project, USDA-NIFA #2011-68002-30029 to GJM; and Agriculture and Food Research Initiative Plant Genome, Genetics and Breeding Program of USDA’s Cooperative State Research and Extension Service, #2009-65300- 05645 to GJM
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