4,370 research outputs found

    Space Borne and Ground-Based Observations of Transient Processes Occurring Around Substorm Onset

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    The combined THEMIS five spacecraft in-situ and ground magnetic and visible camera arrays have advanced considerably our understanding of the causal relationship between midtail plasma flows, transient ionospheric features, and ground magnetic signatures. In particular recent work has shown a connection between equatorward moving visible ionospheric transients and substorm onset, in both white-light and 6300 nm emissions. These observations, together with THEMIS in-situ measurements of bulk flows, provides strict constraints on the sequence of events leading to substorm auroral onset.We first provide a brief summary of these observations, highlighting in particular areas where the two observations differ, and suggest reasons for the differences. Next, by combining the observed correlation of flow and Pi2 waveform with a unified model of global Pi2 generation and substorm current wedge initiation we present a self-consistent description of the dynamical processes and communicative pathways that occur just prior to and during substorm expansion onset

    Changes in public health preparedness services provided to local health departments by regional offices in North Carolina: a comparison of two cross-sectional studies

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    Background: In 2011, seven decentralized Public Health Regional Surveillance Teams (PHRSTs) were restructured into four centralized Public Health Preparedness and Response (PHP&R) regional offices to realign preparedness priorities and essential services with appropriate infrastructure; field-based staff was reduced, saving approximately $1 million. The objective of this study was to understand the impact that restructuring had on services provided to local health departments (LHDs) throughout North Carolina. Methods: A survey to document services that regional offices provide to LHDs in North Carolina was administered by the North Carolina Preparedness and Emergency Response Research Center in 2013. The results were compared to a similar survey from 2009, which identified services provided by regional teams prior to restructuring. Results: Of 69 types of assistance, 14 (20%) were received by 50% or more LHDs in 2012. Compared to 2009, there was a significant decrease in the proportion of LHDs receiving 67% (n = 47) of services. The size of the region served by regional offices was shown to inversely impact the proportion of LHDs receiving services for 25% of services. There was a slight significant decline in perceived quality of the services provided by regional teams in 2012 as comparison to 2009. Conclusions: Following a system-wide review of preparedness in North Carolina, the state’s regional teams were reorganized to refine their focus to planning, exercises, and training. Some services, most notably under the functions of epidemiology and surveillance and public health event response, are now provided by other state offices. However, the study results indicate that several services that are still under the domain of the regional offices were received by fewer LHDs in 2012 than 2009. This decrease may be due to the larger number of counties now served by the four regional offices

    How Dry Are Red Mergers?

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    The focus of current research in galaxy evolution has increasingly turned to understanding the effect that mergers have on the evolution of systems on the red sequence. For those interactions purported to occur dissipationlessly (so called "dry mergers"), it would appear that the role of gas is minimal. However, if these mergers are not completely dry, then even low levels of gas may be detectable. The purpose of our study is to test whether early type galaxies with HI in or around them, or "wet" ellipticals, would have been selected as dry mergers by the criteria in van Dokkum (2005, AJ, 130, 2647). To that end, we examine a sample of 20 early types from the HI Rogues Gallery with neutral hydrogen in their immediate environs. Of these, the 15 brightest and reddest galaxies match the optical dry merger criteria, but in each case, the presence of HI means that they are not truly dry.Comment: 8 pages plus 1 table and 5 figures; accepted for publication in A

    Identification of a Widespread Palmitoylethanolamide Contamination in Standard Laboratory Glassware

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    Introduction: Fatty acid ethanolamides (FAEs) are a family of lipid mediators that participate in a host of biological functions. Procedures for the quantitative analysis of FAEs include organic solvent extraction from biological matrices (e.g., blood), followed by purification and subsequent quantitation by liquid chromatography-mass spectrometry (LC/MS) or gas chromatography-mass spectrometry. During the validation process of a new method for LC/MS analysis of FAEs in biological samples, we observed unusually high levels of the FAE, palmitoylethanolamide (PEA), in blank samples that did not contain any biological material. Materials and Methods: We investigated a possible source of this PEA artifact via liquid chromatography coupled to tandem mass spectrometry, as well as accurate mass analysis. Results: We found that high levels of a contaminant indistinguishable from PEA is present in new 5.75″ glass Pasteur pipettes, which are routinely used by laboratories to carry out lipid extractions. This artifact might account for discrepancies found in the literature regarding PEA levels in human blood serum and other tissues. Conclusions: It is recommended to take into account this pitfall by analyzing potential contamination of the disposable glassware during the validation process of any method used for analysis of FAEs

    Complexity of matrix problems

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    In representation theory, the problem of classifying pairs of matrices up to simultaneous similarity is used as a measure of complexity; classification problems containing it are called wild problems. We show in an explicit form that this problem contains all classification matrix problems given by quivers or posets. Then we prove that it does not contain (but is contained in) the problem of classifying three-valent tensors. Hence, all wild classification problems given by quivers or posets have the same complexity; moreover, a solution of any one of these problems implies a solution of each of the others. The problem of classifying three-valent tensors is more complicated.Comment: 24 page

    Understanding students’ motivation towards proactive career behaviours through goal-setting theory and the job demands–resources model

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    The graduate labour market is highly competitive but little is known about why students vary in their development of employability. This study contributes to the literature by applying goal-setting theory and the job demands–resources model to investigate how motivational processes influence students’ proactive career behaviours. We tested four hypotheses using structural equation modelling and moderation/mediation analysis using a nested model approach; 432 undergraduates from 21 UK universities participated in this cross-sectional study. The results showed that students higher in mastery approach had greater perceived employability mediated by two proactive career behaviours (skill development and network building). Students’ career goal commitment was associated with all four proactive career behaviours (career planning, skill development, career consultation and network building). Students’ academic and employment workloads did not negatively impact their proactive career behaviours. University tutors and career services should therefore encourage students to set challenging career goals that reflect mastery approach

    Athletes’ Beliefs About and Attitudes Towards Taking Banned Performance-Enhancing Substances: A Qualitative Study

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    Elite athletes’ beliefs about, and attitudes toward, taking banned performance enhancing substances were explored in 8 focus-group discussions with 57 athletes from 7 different sports. Discussion was initiated by 3 broad open-ended questions pertaining to 3 important themes likely to affect beliefs and attitudes toward banned performance enhancing substances. Thematic content analysis of interview transcripts revealed 9 lower-order themes emerging under the 3 global themes: personal attitudes (reputation and getting caught, health effects, and financial incentives and rewards), social influences (coaches, parents, and medical staff and sport scientists), and control beliefs (i.e., insufficiency of doping testing, resource availability, and sport level and type). Findings provide insight into the beliefs and attitudes that likely underpin motives and intentions to take banned performance-enhancing substances. Results are generally consistent with, and complement, research adopting quantitative approaches based on social– cognitive models examining the beliefs and attitudes linked to taking banned performance-enhancing substances
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