1,369 research outputs found

    Autoionization effects in ultraviolet absorption spectra of hot gases Scientific report no. 6

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    Autoionization effects in ultraviolet absorption spectra of hot gase

    Shock Tube Determination of Autoionization Lifetime and Oscillator Strengths of the 352 3P 2Po-353P2 2S1/2 Doublet of Al I Scientific Report No. 2

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    Shock tube measurement of autoionization lifetime and oscillator strengths of states above first ionization potential for aluminu

    Absorption line series and autoionization resonance structure analysis in the ultraviolet spectrum of Sr I

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    Photoelectric spectrometer to measure absorption line series and autoionization resonance in ultraviolet spectrum of strontium vapo

    A guide to chemokines and their receptors

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    The chemokines (or chemotactic cytokines) are a large family of small, secreted proteins that signal through cell surface G‐protein coupled heptahelical chemokine receptors. They are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes). Consequently, chemokines play a central role in the development and homeostasis of the immune system, and are involved in all protective or destructive immune and inflammatory responses. Classically viewed as inducers of directed chemotactic migration, it is now clear that chemokines can stimulate a variety of other types of directed and undirected migratory behaviour, such as haptotaxis, chemokinesis, and haptokinesis, in addition to inducing cell arrest or adhesion. However, chemokine receptors on leukocytes can do more than just direct migration, and these molecules can also be expressed on, and regulate the biology of, many non‐leukocytic cell types. Chemokines are profoundly affected by post‐translational modification, by interaction with the extracellular matrix (ECM), and by binding to heptahelical ‘atypical’ chemokine receptors that regulate chemokine localisation and abundance. This guide gives a broad overview of the chemokine and chemokine receptor families; summarises the complex physical interactions that occur in the chemokine network; and, using specific examples, discusses general principles of chemokine function, focussing particularly on their ability to direct leukocyte migration

    Symmetry breaking in crossed magnetic and electric fields

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    We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.Comment: 4 page REVTeX file including 5 postscript files (using psfig) Accepted for publication in Physical Review Letters. Difference from earlier preprint: we have discovered the cause of the earlier apparent discrepancy between experiment and theory and now achieve excellent agreemen

    Master\u27s Project: Evaluating the Effectiveness of Best Management Practices on Rural Backroads of Vermont: A Retrospective Assessment and Cost Analysis

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    Repeated erosion of over 7,000 miles of unpaved roads in Vermont is degrading water quality and draining limited town budgets. Best Management Practices (BMPs), including stone-lined ditches, turn outs, check dams, revetments, culverts and vegetative controls, are recommended by the Vermont Department of Transportation as low cost means of reducing the sediment and phosphorous run-off from backroads. However, their effectiveness, longevity and cost benefit are unknown. To address this gap, I assessed 100 BMPs at 43 erosion control projects constructed between 2005 and 2012 with funding from the Vermont Better Backroads program. BMP condition was compared to environmental factors that foreseeably affected how long they would remain intact. Increased road grade and exposure to flood events were the most significant predictors of project deterioration, although increased age affected specific BMPs. Only ten percent of assessed BMPs had failed, indicating that when properly maintained, BMPs may remain operable for over eight years. To understand the availability and distribution of town funds spent on backroad maintenance, I interviewed road foremen in five small, mountainous towns in Vermont. Town expenditures on repairing repeated road washouts were comparable to annual funds needed for “permanent fixes” of roads preliminarily identified to pose the highest risk to water quality. All towns indicated a willingness to construct more BMPs with further funding, suggesting that a proactive approach to erosion control on backroads will be an efficient use of state money allocated to improving water quality

    'I felt that I do live in the UK now':international students' self-reports of their English language speaking experiences on a pre-sessional programme

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    This article focuses on the English language experiences of a group of pre-sessional students, an under-represented group in the literature on language and education. In particular, it investigates the opportunities that such students have to use English outside the classroom, shown to be a key factor in student satisfaction with their study abroad experience. Drawing on data from questionnaires, interviews and on-line diaries, we show that students have a variety of opportunities to use English; however, these opportunities may require students to engage in complex negotiations right from the beginning of their sojourn in the UK. Micro-analysis of the data shows that agency is a key construct in understanding students' representations of their English encounters as they begin their lives in the UK. The article concludes with some suggestions as to how pre-sessional courses may develop students' linguistic and socio-cultural skills in order that they may interact successfully in English outside the classroom

    The Emerging Aversion to Inequality: Evidence from Poland 1992-2005

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    This paper provides an illustration of the changing tolerance for inequality in a context of radical political and economic transformation and rapid economic growth. We focus on the Polish experience of transition and explore self-declared attitudes of the citizens. Using monthly representative surveys of the population, realized by the Polish poll institute (CBOS) from 1992 to 2005, we identify a structural break in the relation between income inequality and subjective evaluation of well-being. The downturn in the tolerance for inequality (1997) coincides with the increasing distrust of political elites.http://deepblue.lib.umich.edu/bitstream/2027.42/64387/1/wp919.pd
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