12,113 research outputs found

    Promoting Identity Development in the Classroom: A New Role for Academic Faculty

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    This study examined the influence of a structured curricular intervention on the personal and social identity development of college students. The authors implemented a pretest/posttest design using the revised version of the Extended Objective Measure of Ego Identity Status-2 (EOMEIS-2). Significant posttest results supported faculty’s role in developing students’ capabilities beyond the intellectual domain. Finally, the authors discuss collaboration between academic faculty and student affairs practitioners in contributing toward students’ identity development

    A Survey for Outer Satellites of Mars: Limits to Completeness

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    We surveyed the Hill sphere of Mars for irregular satellites. Our search covered nearly the entire Hill Sphere, but scattered light from Mars excluded the inner few arcminutes where the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23.5, which corresponds to radii of about 0.09 km using an albedo of 0.07.Comment: 5 figures (1 color), 2 Tables, to appear in AJ Nov. 200

    Ten year change in forest succession and composition measured by remote sensing

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    Vegetation dynamics and changes in ecological patterns were measured by remote sensing over a 10 year period (1973 to 1983) for 148,406 landscape elements, covering more than 500 sq km in a protected forested wilderness. Quantitative measurements were made possible by methods to detect ecologically meaningful landscape units; these allowed measurement of ecological transition frequencies and calculation of expected recurrence times. Measured ecological transition frequencies reveal boreal forest wilderness as spatially heterogeneous and highly dynamic, with one-sixth of the area in clearings and early successional stages, consistent with recent postulates about the spatial and temporal patterns of natural ecosystems. Differences between managed forest areas and a protected wilderness allow assessment of different management regimes

    Structural variants are a major source of gene expression differences in humans and often affect multiple nearby genes

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    Structural variants (SVs) are an important source of human genome diversity, but their functional effects are poorly understood. We mapped 61,668 SVs in 613 individuals from the GTEx project and measured their effects on gene expression. We estimate that common SVs are causal at 2.66% of eQTLs, a 10.5-fold enrichment relative to their abundance in the genome. Duplications and deletions were the most impactful variant types, whereas the contribution of mobile element insertions was small (0.12% of eQTLs, 1.9-fold enriched). Multitissue analysis of eQTLs revealed that gene-altering SVs show more constitutive effects than other variant types, with 62.09% of coding SV-eQTLs active in all tissues with eQTL activity compared with 23.08% of coding SNV- and indel-eQTLs. Noncoding SVs, SNVs and indels show broadly similar patterns. We also identified 539 rare SVs associated with nearby gene expression outliers. Of these, 62.34% are noncoding SVs that affect gene expression but have modest enrichment at regulatory elements, showing that rare noncoding SVs are a major source of gene expression differences but remain difficult to predict from current annotations. Both common and rare SVs often affect the expression of multiple genes: SV-eQTLs affect an average of 1.82 nearby genes, whereas SNV- and indel-eQTLs affect an average of 1.09 genes, and 21.34% of rare expression-altering SVs show effects on two to nine different genes. We also observe significant effects on rare gene expression changes extending 1 Mb from the SV. This provides a mechanism by which individual SVs may have strong or pleiotropic effects on phenotypic variation

    Molecular characterization of Trichomonas gallinae isolates recovered from the Canadian Maritime provinces’ wild avifauna reveals the presence of the genotype responsible for the European finch trichomonosis epidemic and additional strains

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    Finch trichomonosis, caused by Trichomonas gallinae, emerged in the Canadian Maritime provinces in 2007 and has since caused ongoing mortality in regional purple finch (Carpodacus purpureus) and American goldfinch (Carduelis tristis) populations. Trichomonas gallinae was isolated from (1) finches and rock pigeons (Columbia livia) submitted for post-mortem or live-captured at bird feeding sites experiencing trichomonosis mortality; (2) bird seed at these same sites; and (3) rock pigeons live-captured at known roosts or humanely killed. Isolates were characterized using internal transcribed spacer (ITS) region and iron hydrogenase (Fe-hyd) gene sequences. Two distinct ITS types were found. Type A was identical to the UK finch epidemic strain and was isolated from finches and a rock pigeon with trichomonosis; apparently healthy rock pigeons and finches; and bird seed at an outbreak site. Type B was obtained from apparently healthy rock pigeons. Fe-hyd sequencing revealed six distinct subtypes. The predominant subtype in both finches and the rock pigeon with trichomonosis was identical to the UK finch epidemic strain A1. Single nucleotide polymorphisms in Fe-hyd sequences suggest there is fine-scale variation amongst isolates and that finch trichomonosis emergence in this region may not have been caused by a single spill-over event

    Expanded Thruster Mass Model Incorporating Nested Hall Thrusters

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143089/1/6.2017-4729.pd

    Freshwater Bacteria are Stoichiometrically Flexible with a Nutrient Composition Similar to Seston

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    Although aquatic bacteria are assumed to be nutrient-rich, they out-compete other foodweb osmotrophs for nitrogen (N) and phosphorus (P) an apparent contradiction to resource ratio theory. This paradox could be resolved if aquatic bacteria were demonstrated to be nutrient-poor relative other portions of the planktonic food web. In a survey of >120 lakes in the upper Midwest of the USA, the nutrient content of bacteria was lower than previously reported and very similar to the Redfield ratio, with a mean biomass composition of 102:12:1 (C:N:P). Individual freshwater bacterial isolates grown under P-limiting and P-replete conditions had even higher C:P and N:P ratios with a mean community biomass composition ratio of 875C:179N:1P suggesting that individual strains can be extremely nutrient-poor, especially with respect to P. Cell-specific measurements of individual cells from one lake confirmed that low P content could be observed at the community level in natural systems with a mean biomass composition of 259C:69N:1P. Variability in bacterial stoichiometry is typically not recognized in the literature as most studies assume constant and nutrient-rich bacterial biomass composition. We present evidence that bacteria can be extremely P-poor in individual systems and in culture, suggesting that bacteria in freshwater ecosystems can either play a role as regenerators or consumers of inorganic nutrients and that this role could switch depending on the relationship between bacterial biomass stoichiometry and resource stoichiometry. This ability to switch roles between nutrient retention and regeneration likely facilitates processing of terrestrial organic matter in lakes and rivers and has important implications for a wide range of bacterially mediated biogeochemical processes

    The Preservation and Protection of Native Biodiversity in the Guadalupe Nipomo Dunes Complex

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    The Guadalupe Nipomo Dunes Complex (GNDC) is located within the California Floristic Province, a biodiversity hotspot characterized by high rates of endemism and exceptional loss of habitat. In 1980, the US Fish and Wildlife Service described the GNDC as, “the most unique and fragile ecosystem in the State of California,” and ranked it first on a list of 49 habitat areas needing state protection. It is the largest coastal dune area in California and it is one of the last remaining, relatively intact ecosystems of its type and size in the western United States. The growing recognition of species decline and the limited number of dollars allocated to conservation and restoration have led to development of new conservation planning software and conservation strategies. Marxan and Zonation were selected for this project due to their worldwide acceptance in biodiversity conservation planning as well as their specialization in identifying priority zones for conservation. This document describes the unique use of conservation planning software to select areas for resource allocation. It outlines the process of selecting conservation targets, the habitats and species important to overall health of an ecosystem, by using the expert involvement approach. Most importantly, this document outlines areas of high biodiversity that will later be used to allocate resources for the preservation and protection of biodiversity within the Guadalupe Nipomo Dunes Complex. Introduced species are the second-leading cause (after habitat degradation/loss), causing or contributing to the decline in species abundance and diversity. Ehrharta calycina Smith has become highly invasive in the coastal dune communities of Central and Southern California and currently holds a “high” CAL-IPC inventory rating, defined as a species with severe ecological impacts on physical processes, plant and animal communities and vegetation structure as well as reproductive biology and other attributes conducive to moderate to high rates of dispersal and establishment. Ehrharta calycina is a prolific seeder and stores its seeds annually in the soil, collecting a substantial seedbank. Little is known about E.calycina outside its native range, as its invasion into California coastal ecosystem is fairly recent. A field experiment in the Guadalupe Nipomo Dunes Complex assessed the contribution of seeds originating from the seedbank as compared to seeds from above ground either dropping from maternal plants or blown in from outside the plots to the establishment of new E. calycina cover. After a nine month perios, new E. calycina cover from both sources was not significantly different. Visible coverage of E. calycina began 77 days (November 24, 2015) after plot installation. After nine months of surveying, coverage reached 19% in the Seedbank Present treatment and 21% in the Seedbank Absent treatment. There was no significant effect associated with the slope and aspect of the experimental locations. This experiment will aid in management of this invasive species by educating land managers to focus on preventing current seed production of established individuals as those sources of seed were as important as those originating in the seedbank. Stimulating germination of seeds from the seedbank with a concomitant management strategy such as herbicide application or physical removal will likely be the most effective methods for dealing with seeds in the seedbank

    Looking backward, looking forward: the city region of the mid-21st century

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    Emerging as a serious tool of analysis in the United States around 1950, the city region concept was increasingly applied in a European context after 1980. Since 2000, it has evolved further with recognition of the polycentric mega-city region, first recognised in Eastern Asia but now seen as an emerging urban form both in Europe and the United States. The paper speculates on the main changes that may impact on the growth and development of such complex urban regions in the first half of the 21st century, concluding that achieving the goal of polycentric urban development may prove more complex than at first it may seem
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