486 research outputs found

    Th e role of prescribed burning in maintenance of an endangered plant species, Lomatium bradshawii.

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    Abstract. Responses of a federally listed endangered plant species, Lomatium bradshawii, to the use of fire as a management tool for maintaining remnant wetland prairies were evaluated at two public land areas in the Willamette Valley of western Oregon. Areas containing L. bradshawii were treated with two or three fall season prescribed burns during a nine-year period. Foliar crown area, height, umbellets, and schizocarps of 150 L. bradshawii at Rose Prairie and 250 at Fisher Butte and the recruitment and density of L. bradshawii in 2-m 2 plots at both sites were documented during 1988-1996. When both sites were considered together, crown area, height, umbellets, and schizocarps per plant initially responded positively to burn treatments, but increases were not consistent across years or sites. Crown area tended to increase and then decline after each burn. Burning initially enhanced schizocarp production at both sites; schizocarps declined one or two years after burning but remained much higher in the burn treatments than in controls until 1996. Seedling production was not correlated with schizocarp production at either site. Umbellet and schizocarp production were not correlated with January-June temperatures or precipitation at the nearest weather station. Burning accentuated differences in size and reproductive capacity of L. bradshawii at the two sites and differentially affected recruitment and density. Random resampling of L. bradshawii in 1997 indicated that effects of repeated burning during the previous eight years were hard to detect. At Rose Prairie, foliar crown area, height, number of leaves, umbellets, and schizocarps in 1997 were similar or lower with burning than in unburned controls. At Fisher Butte, L. bradshawii in the two burn treatment were similar to control plants, but three burns significantly increased foliar crown area, number of leaves, and schizocarps. Monitoring recovery for one or two years after a burn may only capture the initial stimulation provided by burning and may foster unrealistically high expectations concerning the viability of an endangered plant population

    Cyborg Activism: Exploring the reconfigurations of democratic subjectivity in Anonymous

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    This article develops the concept of cyborg activism as novel configuration of democratic subjectivity in the Information Age by exploring the online collectivity Anonymous as a prototype. By fusing elements of human/machine and organic/digital the cyborg disrupts modern logics of binary thinking. Cyborg activism emerges as the reconfiguration of equality/hierarchy, reason/emotion, and nihilism/idealism. Anonymous demonstrates how through the use of contingent and ephemeral digital personae hierarchies in cyborg activism prove more volatile than in face-to-face settings. Emotions appear as an essential part of a politics of passion, which enables pursuing laughter and joy, expressing anger, and experiencing empowerment as part of a reasoned, strategic politics. Anonymous’ political content reconfigures nihilist sentiments, frustration, and political disenchantment on the one hand with idealist world views on the other. This enables the cohabitation and partial integration of a great diversity of political claims rooted in various ideologies

    Communication in Diagnostic Radiology

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    Communication in the diagnostic radiology department in regard to the current work load has been discussed with certain recommendations being made to increase efficiency. The need for improvement in communication equipment and techniques is necessitated by problems facing diagnostic radiology today.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73519/1/j.1440-1673.1972.tb01316.x.pd

    Phenome-Wide Association Study (PheWAS) for Detection of Pleiotropy within the Population Architecture using Genomics and Epidemiology (PAGE) Network

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    Using a phenome-wide association study (PheWAS) approach, we comprehensively tested genetic variants for association with phenotypes available for 70,061 study participants in the Population Architecture using Genomics and Epidemiology (PAGE) network. Our aim was to better characterize the genetic architecture of complex traits and identify novel pleiotropic relationships. This PheWAS drew on five population-based studies representing four major racial/ethnic groups (European Americans (EA), African Americans (AA), Hispanics/Mexican-Americans, and Asian/Pacific Islanders) in PAGE, each site with measurements for multiple traits, associated laboratory measures, and intermediate biomarkers. A total of 83 single nucleotide polymorphisms (SNPs) identified by genome-wide association studies (GWAS) were genotyped across two or more PAGE study sites. Comprehensive tests of association, stratified by race/ethnicity, were performed, encompassing 4,706 phenotypes mapped to 105 phenotype-classes, and association results were compared across study sites. A total of 111 PheWAS results had significant associations for two or more PAGE study sites with consistent direction of effect with a significance threshold of p<0.01 for the same racial/ethnic group, SNP, and phenotype-class. Among results identified for SNPs previously associated with phenotypes such as lipid traits, type 2 diabetes, and body mass index, 52 replicated previously published genotype-phenotype associations, 26 represented phenotypes closely related to previously known genotype-phenotype associations, and 33 represented potentially novel genotype-phenotype associations with pleiotropic effects. The majority of the potentially novel results were for single PheWAS phenotype-classes, for example, for CDKN2A/B rs1333049 (previously associated with type 2 diabetes in EA) a PheWAS association was identified for hemoglobin levels in AA. Of note, however, GALNT2 rs2144300 (previously associated with high-density lipoprotein cholesterol levels in EA) had multiple potentially novel PheWAS associations, with hypertension related phenotypes in AA and with serum calcium levels and coronary artery disease phenotypes in EA. PheWAS identifies associations for hypothesis generation and exploration of the genetic architecture of complex traits

    Variation in LPA Is Associated with Lp(a) Levels in Three Populations from the Third National Health and Nutrition Examination Survey

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    The distribution of lipoprotein(a) [Lp(a)] levels can differ dramatically across diverse racial/ethnic populations. The extent to which genetic variation in LPA can explain these differences is not fully understood. To explore this, 19 LPA tagSNPs were genotyped in 7,159 participants from the Third National Health and Nutrition Examination Survey (NHANES III). NHANES III is a diverse population-based survey with DNA samples linked to hundreds of quantitative traits, including serum Lp(a). Tests of association between LPA variants and transformed Lp(a) levels were performed across the three different NHANES subpopulations (non-Hispanic whites, non-Hispanic blacks, and Mexican Americans). At a significance threshold of p<0.0001, 15 of the 19 SNPs tested were strongly associated with Lp(a) levels in at least one subpopulation, six in at least two subpopulations, and none in all three subpopulations. In non-Hispanic whites, three variants were associated with Lp(a) levels, including previously known rs6919246 (p = 1.18×10−30). Additionally, 12 and 6 variants had significant associations in non-Hispanic blacks and Mexican Americans, respectively. The additive effects of these associated alleles explained up to 11% of the variance observed for Lp(a) levels in the different racial/ethnic populations. The findings reported here replicate previous candidate gene and genome-wide association studies for Lp(a) levels in European-descent populations and extend these findings to other populations. While we demonstrate that LPA is an important contributor to Lp(a) levels regardless of race/ethnicity, the lack of generalization of associations across all subpopulations suggests that specific LPA variants may be contributing to the observed Lp(a) between-population variance
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