593 research outputs found

    Low noise optical receivers

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    the paper describes low noise first stage optical receivers.Analysis of operating conditions affecting signal-to-noise ratio has been carried out.Each preamplifier was carefully optimised to work with particular type of the detector

    Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient

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    We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide

    Prime movers : mechanochemistry of mitotic kinesins

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    Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

    Team faculty approach to introduce grant writing experience in an undergraduate nursing service learning course

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    Session presented on Monday, November 9, 2015 and Tuesday, November 10, 2015: Introduction: During the nursing program, students of great diversity are able to achieve knowledge, leadership and professional qualities while fostering collaboration with four diverse communities. Undergraduate nursing students are introduced to research, but the development of their research skills does not end after the research class. Threading service learning activities across the curriculum that promotes research skills such as grant writing is a faculty team approach. The purpose of this innovative educational project is to use an evidenced based approach to strategically identify high impact research activities to inspire service learning and research skills among nursing students in a newly developed undergraduate nursing program. The first step is providing a grant writing opportunity. This includes the collaboration of the faculty team, nursing students, and community leaders to support the activity. Faculty will direct students toward service learning activities that incorporate research skills. Background: A newly developed nursing program that began in 2012 at a faith-based Hispanic serving university in southeast Texas explored evidence to support the strategic placement of real-world experiences in development of nurse research scientists. The program requires the research course, clinical inquiry, during the second semester. The grant writing service learning activity is incorporated in the third semester community nursing course. The project is consistent with the BSN nursing program outcomes listed below. Provide relationship-centered nursing care that is grounded in nursing theory and guided by evidence based best practice standards to support individuals, families and communities in achieving their goals for healing and wholeness. Utilize nursing theory, nursing research and methods of clinical inquiry as the basis for continuously enhancing the quality of care. Participate in the social advocacy role of the nurse through membership in professional organizations and engagement in community service. Methods: The project will be evaluated using qualitative and quantitative surveys that target the faculty team, community nursing students, and community leaders. Surveys are focused on five areas. Provide instruction and guidance in grant writing; Allow student groups to submit for actual funds made available through a Teaching Enhancement Grant; Provide the ability to disseminate results via posters at various venues; Support the missions of the four designated communities during service-learning experiences; Support the goals and mission of the University and the School of Nursing. Implementation The 2016 nursing cohort completed a nursing research course the second semester of their nursing program. The community course (third semester of nursing program) continues to build toward the on-going professional development of nursing students. Students in the community course are divided into four groups and partnered with four identified diverse communities that have volunteered to participate in the following phases. Community Assessment: Development of community diagnosis of problem/needs and goals; Project Planning; Project Implementation; Project Evaluation and Dissemination of Results. A team of five faculty members in the community course are charged with guiding, instructing, and mentoring students in the application process, poster development and dissemination of results. The course coordinator will determine the grant awards based on the standardized criteria of feasibility, sustainability, merit, evaluation plan, and budget. Total project time allowed is three months. Results: Results pending. Survey results from the faculty team, students, and community leaders will be analyzed and presented at the end of the project. In addition, the number and quality of proposal applications submitted, and the number of proposals funded will be evaluated and presented. Conclusion: The project seeks to provide evidence to support a service learning grant writing activity in the curriculum. Findings will help to identify additional activities to enrich future courses and achieve enhanced community collaboration by transforming nursing practice

    YouTube Video Project: A Cool Way to Learn Communication Ethics

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    The millennial generation embraces new technologies as a natural way of accessing and exchanging information, staying connected, and having fun. YouTube, a video-sharing site that allows users to upload, view, and share video clips, is among the latest “cool” technologies for enjoying quick laughs, employing a wide variety of corporate activities, and also communicating relevant, engaging instructional content for today’s students. This article describes a YouTube video class project that is a natural fit with today’s students because it involves cutting-edge social media while addressing a critical component of professional development—communication ethics. This project encourages critical thinking, creativity, and applied learning in a team environment using a “cool” new media tool

    The Effect of Token Economies on Student Behavior in the Preschool Classroom: A Meta-Analysis

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    There has been a recent push in the literature to identify and use more evidence-based practices for positive behavioral supports for challenging student behaviors in the classroom environment. Further, interest in targeting early education environments such as preschool has been growing given the persistence of behavioral difficulties in the absence of early and effective intervention (Campbell & Ewing, 1990; Kazdin, 1987; Powell et al., 2006; Stormont, 2002). Two previous meta-analyses (Maggin et al., 2011; Soares et al., 2016) provided some initial support for effectiveness of token economies with challenging student behavior; however, the inclusion of the preschool setting was limited and both studies used older versions of design standards to evaluate the quality of studies in the literature. The present study served to extend those meta-analyses by targeting preschool classrooms. Further, the current study included the most recent What Works Clearinghouse Design Standards to evaluate whether token economies meet criteria as an evidence-based practice. Ten studies were included in the final analyses. Two sets of effect sizes were calculated: Baseline-Corrected Tau and Hedge’s g. An omnibus effect size showed an overall large effect; however, similar to previous meta-analyses, several methodological concerns were identified. Moderator analyses for several variables were conducted; however, no moderator analyses were significant. Limitations and future directions were discussed

    Imaging the nanoscale organization of peptidoglycan in living Lactococcus lactis cells

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    Peptidoglycans provide bacterial cell walls with mechanical strength. The spatial organization of peptidoglycan has previously been difficult to study. Here, atomic force microscopy, together with cells carrying mutations in cell-wall polysaccharides, has allowed an in-depth study of these molecules

    Rickettsiae Induce Microvascular Hyperpermeability via Phosphorylation of VE-Cadherins: Evidence from Atomic Force Microscopy and Biochemical Studies

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    The most prominent pathophysiological effect of spotted fever group (SFG) rickettsial infection of microvascular endothelial cells (ECs) is an enhanced vascular permeability, promoting vasogenic cerebral edema and non-cardiogenic pulmonary edema, which are responsible for most of the morbidity and mortality in severe cases. To date, the cellular and molecular mechanisms by which SFG Rickettsia increase EC permeability are largely unknown. In the present study we used atomic force microscopy (AFM) to study the interactive forces between vascular endothelial (VE)-cadherin and human cerebral microvascular EC infected with R. montanensis, which is genetically similar to R. rickettsii and R. conorii, and displays a similar ability to invade cells, but is non-pathogenic and can be experimentally manipulated under Biosafety Level 2 (BSL2) conditions. We found that infected ECs show a significant decrease in VE-cadherin-EC interactions. In addition, we applied immunofluorescent staining, immunoprecipitation phosphorylation assay, and an in vitro endothelial permeability assay to study the biochemical mechanisms that may participate in the enhanced vascular permeability as an underlying pathologic alteration of SFG rickettsial infection. A major finding is that infection of R. montanensis significantly activated tyrosine phosphorylation of VE-cadherin beginning at 48 hr and reaching a peak at 72 hr p.i. In vitro permeability assay showed an enhanced microvascular permeability at 72 hr p.i. On the other hand, AFM experiments showed a dramatic reduction in VE-cadherin-EC interactive forces at 48 hr p.i. We conclude that upon infection by SFG rickettsiae, phosphorylation of VE-cadherin directly attenuates homophilic protein–protein interactions at the endothelial adherens junctions, and may lead to endothelial paracellular barrier dysfunction causing microvascular hyperpermeability. These new approaches should prove useful in characterizing the antigenically related SFG rickettsiae R. conorii and R. rickettsii in a BSL3 environment. Future studies may lead to the development of new therapeutic strategies to inhibit the VE-cadherin-associated microvascular hyperpermeability in SFG rickettsioses
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