3,653 research outputs found

    FLORA AND VEGETATION OF CONEFLOWER GLACIAL DRIFT HILL PRAIRIE NATURAL AREA, MOULTRIE COUNTY, ILLINOIS

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    The vascular flora of Coneflower Glacial Drift Hill Prairie Natural Area in Moultrie County, east-central Illinois, was studied during the growing seasons of 2002 and 2003. The prairie is located on a steep SW-facing hillside of the Cerro Gordo Glacial Moraine, overlooking the Kaskaskia River Valley and Lake Shelbyville. The flora was documented by general reconnaissance, and the structure of the vegetation was sampled in September 2003 using 0.25 m2 plots placed along two transects. The site supported 164 vascular plant species (including one named hybrid). The native grasses with the highest importance values were Andropogon gerardii (big bluestem) and Schizachyrium scoparium (little bluestem). Important forbs included Euphorbia cora/lata (flowering spurge), Helicmthus divaricatus (woodland sunflower), Ratibida pinna/a (drooping coneflower), and Comandra umbe/lma (false toadflax). Exotic species were represented by 28 taxa, 16.4% of the flora. The community had a Floristic Quality Index of 38.82, indicating a site of statewide significance

    Genes of the GadX-GadW Regulon in Escherichia coli

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    Acid in the stomach is thought to be a barrier to bacterial colonization of the intestine. Escherichia coli, however, has three systems for acid resistance, which overcome this barrier. The most effective of these systems is dependent on transport and decarboxylation of glutamate. GadX regulates two genes that encode isoforms of glutamate decarboxylase critical to this system, but additional genes associated with the glutamate-dependent acid resistance system remained to be identified. The gadX gene and a second downstream araC-like transcription factor gene, gadW, were mutated separately and in combination, and the gene expression profiles of the mutants were compared to those of the wild-type strain grown in neutral and acidified media under conditions favoring induction of glutamate-dependent acid resistance. Cluster and principal-component analyses identified 15 GadX-regulated, acid-inducible genes. Reverse transcriptase mapping demonstrated that these genes are organized in 10 operons. Analysis of the strain lacking GadX but possessing GadW confirmed that GadX is a transcriptional activator under acidic growth conditions. Analysis of the strain lacking GadW but possessing GadX indicated that GadW exerts negative control over three GadX target genes. The strain lacking both GadX and GadW was defective in acid induction of most but not all GadX target genes, consistent with the roles of GadW as an inhibitor of GadX-dependent activation of some genes and an activator of other genes. Resistance to acid was decreased under certain conditions in a gadX mutant and even more so by combined mutation of gadX and gadW. However, there was no defect in colonization of the streptomycin-treated mouse model by the gadX mutant in competition with the wild type, and the gadX gadW mutant was a better colonizer than the wild type. Thus, E. coli colonization of the mouse does not appear to require glutamate-dependent acid resistance

    Ultra-high energy cosmic rays may come from clustered sources

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    Clustering of cosmic-ray sources affects the flux observed beyond the cutoff imposed by the cosmic microwave background and may be important in interpreting the AGASA, Fly's Eye, and HiRes data. The standard deviation, sigma, in the predicted number, N, of events above 10^{20} eV is sigma/N = 0.9(r_0/10 Mpc)^{0.9}, where r_0 is the unknown scale length of the correlation function (r_0 = 10 Mpc for field galaxies). Future experiments will allow the determination of r_0 through the detection of anisotropies in arrival directions of ~ 10^{20} eV cosmic-rays over angular scales of Theta ~ r_0/30 Mpc.Comment: Accepted for publication in Astrophysical Journa

    Community Service Learning Increases Communication Skills Across the Business Curriculum

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    Community service learning offers a unique and rewarding way for business students to reinforce communication capabilities while developing lifelong career and social skills. This article defines community service learning, discusses its importance to business as well as higher education, and describes three community service learning projects. Students in these projects taught elementary students, designed a computer system for a community nonprofit, and developed accounting systems for university divisions. In doing so, they enhanced their understanding of classroom theories and communication skills through service-learning

    Evaluation of a Circumference-based Prediction Equation to Assess Body Composition Changes in Men

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    International Journal of Exercise Science 6(3) : 188-198, 2013. This study evaluated the validity of the current U.S. Department of Defense (DOD) circumference-based prediction equation for males to detect body composition changes in comparison to air-displacement plethysmography (ADP). Body composition was assessed using ADP and the DOD equation at the beginning and end of an academic school year among 21 male (18-29 years-old) Army ROTC cadets. Body mass significantly increased (+1.8 Kg) after 9 months. Significant method by time interactions for percent body fat (percent body fat), fat mass (FM), and fat-free mass were found (p = 0.022, p = 0.023, p = 0.023, respectively) as body composition changes were not tracked equally by the two methods. Regression and Bland-Altman analyses indicated a lack of agreement between methods as the DOD equation underestimated percent body fat and FM changes in comparison to ADP. Results suggest the DOD equation for males cannot adequately detect body composition changes following a small body mass gain

    Structural insights into the calcium-dependent interaction between calbindin-D28K and caspase-3

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    AbstractThe regulation of apoptosis involves a complicated cascade requiring numerous protein interactions including the pro-apoptotic executioner protein caspase-3 and the anti-apoptotic calcium-binding protein calbindin-D28K. Using isothermal titration calorimetry, we show that calbindin-D28K binds caspase-3 in a Ca2+-dependent fashion. Molecular docking and conformational sampling studies of the Ca2+-loaded capase-3/calbindin-D28K interaction were performed in order to isolate potentially crucial intermolecular contacts. Residues in the active site loops of caspase-3 and EF-hands 1 and 2 of calbindin-D28K were shown to be critical to the interaction. Based on these studies, a model is proposed to help understand how calbindin-D28K may deactivate caspase-3 upon binding.Structured summary of protein interactionsCalbindin-D28K and Caspase-3 bind by isothermal titration calorimetry (View interaction
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