28 research outputs found

    Changing Higher Education Learning with Web 2.0 and Open Education Citation, Annotation, and Thematic Coding Appendices

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    Appendices of citations, annotations and themes for research conducted on four websites: Delicious, Wikipedia, YouTube, and Facebook

    Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

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    BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

    Origin of Galactic and Extragalactic Magnetic Fields

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    A variety of observations suggest that magnetic fields are present in all galaxies and galaxy clusters. These fields are characterized by a modest strength (10^{-7}-10^{-5} G) and huge spatial scale (~Mpc). It is generally assumed that magnetic fields in spiral galaxies arise from the combined action of differential rotation and helical turbulence, a process known as the alpha-omega dynamo. However fundamental questions concerning the nature of the dynamo as well as the origin of the seed fields necessary to prime it remain unclear. Moreover, the standard alpha-omega dynamo does not explain the existence of magnetic fields in elliptical galaxies and clusters. The author summarizes what is known observationally about magnetic fields in galaxies, clusters, superclusters, and beyond. He then reviews the standard dynamo paradigm, the challenges that have been leveled against it, and several alternative scenarios. He concludes with a discussion of astrophysical and early Universe candidates for seed fields.Comment: 67 pages, 17 figures, accepted for publication in Reviews of Modern Physic

    Exploring the Relationships Between Tutor Background, Tutor Training, and Student Learning: A Problem-based Learning Meta-Analysis

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    Despite years of primary research on problem-based learning and literature reviews, no systematic effort has been made to analyze the relationship between tutor characteristics and student learning outcomes. In an effort to fill that gap the following meta-analysis coded 223 outcomes from 94 studies with small but positive gains for PBL students (g = 0.24). Specific sub-group analyses indicate randomly controlled designs may be more sensitive to differences that favor PBL students, even while there is no relationship between tutor content expertise and student learning. Perhaps surprisingly, student learning decreases as tutor experience increases. Limitations and future work are discussed within a context of scholarly and practical significance

    PSY 7670 - Literature Reviews, Spring 2008

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    This course is designed to help students in doctoral programs write a literature review that is appropriate for a dissertation or thesis proposal. The course will emphasize skills for writing the Problem Statement and conducting and writing the Review of Literature. Even though the Procedures section is an important part of the dissertation proposal, it will not be dealt with extensively in this class. Other courses which deal specifically with the appropriate design, analysis, and interpretation issues which the student will use for his or her research should be taken prior to this course. Substantial time will be devoted to critiquing previously written Literature Reviews as a way of helping the student understand what differentiates between a well-written and poorly-written literature review

    Dispersal of Erwinia carotovora subsp. atroseptica in splash droplets

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    Water drops, diameter 4 mm, fell 13 mm onto suspensions of cells ofErwinia carotovora subsp.atroseptica containing Mg (ANS) dye. The resulting splash droplets were collected on ohotographic film, on Petri plates containing pectate agar or on fresh potato slices. Fewer droplets produced craters in the pectate than were detected on the film by fluorescence of the dye. Slices did not rot at some distances and with some bacterial concentrations, although craters developed in adjacent pectate plates suggesting that fewer bacteria could produce a crater than were needed to initiate a rot in a slice. The proportion of droplets producing craters increased as the concentration of bacteria increased from 102 to 108 cells ml1. In still air, droplets and craters were not detected beyond ca. 125 cm from the point oPeer reviewe

    Data from: Comparative genomics to explore phylogenetic relationship, cryptic sexual potential and host specificity of Rhynchosporium species on grasses

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    Background: The Rhynchosporium species complex consists of hemibiotrophic fungal pathogens specialized to different sweet grass species including the cereal crops barley and rye. A sexual stage has not been described, but several lines of evidence suggest the occurrence of sexual reproduction. Therefore, a comparative genomics approach was carried out to disclose the evolutionary relationship of the species and to identify genes demonstrating the potential for a sexual cycle. Furthermore, due to the evolutionary very young age of the five species currently known, this genus appears to be well-suited to address the question at the molecular level of how pathogenic fungi adapt to their hosts. Results: The genomes of the different Rhynchosporium species were sequenced, assembled and annotated using ab initio gene predictors trained on several fungal genomes as well as on Rhynchosporium expressed sequence tags. Structures of the rDNA regions and genome-wide single nucleotide polymorphisms provided a hypothesis for intra-genus evolution. Homology screening detected core meiotic genes along with most genes crucial for sexual recombination in ascomycete fungi. In addition, a large number of cell wall-degrading enzymes that is characteristic for hemibiotrophic and necrotrophic fungi infecting monocotyledonous hosts were found. Furthermore, the Rhynchosporium genomes carry a repertoire of genes coding for polyketide synthases and non-ribosomal peptide synthetases. Several of these genes are missing from the genome of the closest sequenced relative, the poplar pathogen Marssonina brunnea, and are possibly involved in adaptation to the grass hosts. Most importantly, six species-specific genes coding for protein effectors were identified in R. commune. Their deletion yielded mutants that grew more vigorously in planta than the wild type. Conclusion: Both cryptic sexuality and secondary metabolites may have contributed to host adaptation. Most importantly, however, the growth-retarding activity of the species-specific effectors suggests that host adaptation of R. commune aims at extending the biotrophic stage at the expense of the necrotrophic stage of pathogenesis. Like other apoplastic fungi Rhynchosporium colonizes the intercellular matrix of host leaves relatively slowly without causing symptoms, reminiscent of the development of endophytic fungi. Rhynchosporium may therefore become an object for studying the mutualism-parasitism transition

    The biology of Botrytis spp. on Vicia beans and chocolate spot disease-a review

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