2,730 research outputs found

    Evaluating the Impact of Altmetrics

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    Objectives: Librarians, publishers, and researchers have long placed significant emphasis on journal metrics such as the impact factor. However, these tools do not take into account the impact of research outside of citations and publications. Altmetrics seek to describe the reach of scholarly activity across the Internet and social media to paint a more vivid picture of the scholarly landscape. Methods: In order to examine the impact of altmetrics on scholarly activity, it is helpful to compare these new tools to an existing method. Citation counts are currently the standard for determining the impact of a scholarly work, and two studies were conducted to examine the correlation between citation count and altmetric data. First, a set of highly cited papers was chosen across a variety of disciplines, and their citation counts were compared with the altmetrics generated from Total-Impact.org. Second, to evaluate the hypothesized increased impact of altmetrics on recently published articles, a set of articles published in 2011 were taken from a sampling of journals with high impact factors, both subscription-based and open access, and the altmetrics were then compared to their citation counts

    The Impossible Thought of Georges Bataille: A Consciousness That Laughs and Cries

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    This thesis labors to unpack Georges Bataille’s enigmatic statement, “to laugh is to think”, treating this “impossible thought” as a paradigmatic expression of Bataille’s self-characterized “philosophy of laughter.” Overall, this thesis interrogates Bataille’s “philosophy of laughter” as an attempt to stimulate an “awakening” of consciousness to the dissolution of consciousness. En route, this thesis argues that such an “awakening” evokes a privileged expression of the movement of “communication” around which Bataille’s theoretical writing is structured, positing the “philosophy of laughter” as an effort to solder the movement of “communication” through the domain of epistemology itself

    Systematic versus opportunistic risk assessment for the primary prevention of cardiovascular disease

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    Background Screening programmes can potentially identify people at high cardiovascular risk and reduce cardiovascular disease (CVD) morbidity and mortality. However, there is currently not enough evidence showing clear clinical or economic benefits of systematic screening-like programmes over the widely practised opportunistic risk assessment of CVD in primary care settings. Objectives The primary objective of this review was to assess the effectiveness, costs and adverse effects of systematic risk assessment compared to opportunistic risk assessment for the primary prevention of CVD. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library, MEDLINE, EMBASE on 30 January 2015, and Web of Science Core Collection and additional databases on the Cochrane Library on 4 December 2014. We also searched two clinical trial registers and checked reference lists of relevant articles. We applied no language restrictions. Selection criteria We selected randomised controlled trials (RCTs) that assessed the effects of systematic risk assessment, defined as a screening-like programme involving a predetermined selection process of people, compared with opportunistic risk assessment which ranged from no risk assessment at all to incentivised case finding of CVD and related risk factors. Participants included healthy adults from the general population, including those who are at risk of CVD. Data collection and analysis Two review authors independently selected studies. One review author extracted data and assessed them for risk of bias and a second checked them. We assessed evidence quality using the GRADE approach and present this in a ’Summary of findings’ table. Main results Nine completed RCTs met the inclusion criteria, of which four were cluster-randomised. We also identified five ongoing trials. The included studies had a high or unclear risk of bias, and the GRADE ratings of overall quality were low or very low. The length of follow-up varied from one year in four studies, three years in one study, five or six years in two studies, and ten years in two studies. Eight studies recruited participants from the general population, although there were differences in the age ranges targeted. One study recruited family members of cardiac patients (high risk assessment). There were considerable differences between the studies in the interventions received by the intervention and control groups. There was insufficient evidence to stratify by the types of risk assessment approaches. Limited data were available on all-cause mortality (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.92 to 1.02; 3 studies,103,571 participants, I² = 0%; low-quality evidence) and cardiovascular mortality (RR 1.00, 95% CI 0.90 to 1.11; 2 studies, 43,955 participants, I² = 0%), and suggest that screening has no effect on these outcomes. Data were also limited for combined non-fatal endpoints; overall, evidence indicates no difference in total coronary heart disease (RR 1.01, 95% CI 0.95 to 1.07; 4 studies, 5 comparisons, 110,168 participants, I² = 0%; low-quality evidence), non-fatal coronary heart disease (RR 0.98, 95% CI 0.89 to 1.09; 2 studies, 43,955 participants, I² = 39%), total stroke (RR 0.99, 95% CI 0.90 to 1.10; 2 studies, 79,631 participants, I² = 0%, low-quality evidence), and non-fatal stroke (RR 1.17, 95% CI 0.94 to 1.47; 1 study, 20,015 participants). Overall, systematic risk assessment appears to result in lower total cholesterol levels (mean difference (MD) -0.11 mmol/l, 95% CI -0.17 to -0.04, 6 studies, 7 comparisons, 12,591 participants, I² = 57%; very low-quality evidence), lower systolic blood pressure (MD -3.05 mmHg, 95% CI -4.84 to -1.25, 6 studies, 7 comparisons, 12,591 participants, I² = 82%; very low-quality evidence) and lower diastolic blood pressure (MD -1.34 mmHg, 95% CI -1.76 to -0.93, 6 studies, 7 comparisons, 12,591 participants, I² = 0%; low-quality evidence). One study assessed adverse effects and found no difference in psychological distress at five years (1126 participants). Authors' conclusions The results are limited by the heterogeneity between trials in terms of participants recruited, interventions and duration of follow-up. Limited data suggest that systematic risk assessment for CVD has no statistically significant effects on clinical endpoints. There is limited evidence to suggest that CVD systematic risk assessment may have some favourable effects on cardiovascular risk factors. The completion of the five ongoing trials will add to the evidence base

    Galactic Plane HÎą\alpha Surveys: IPHAS & VPHAS+

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    The optical Galactic Plane HÎą\alpha surveys IPHAS and VPHAS+ are dramatically improving our understanding of Galactic stellar populations and stellar evolution by providing large samples of stars in short lived, but important, evolutionary phases, and high quality homogeneous photometry and images over the entire Galactic Plane. Here I summarise some of the contributions these surveys have already made to our understanding of a number of key areas of stellar and Galactic astronomy.Comment: 5 pages, 2 figures, refereed proceeding of the "The Universe of Digital Sky Surveys" conference, November 2014, to be published in the Astrophysics and Space Science Proceeding

    Disentangling the spatial substructure of Cygnus OB2 from Gaia DR2

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    Š 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyFor the first time, we have explored the spatial substructure of the Cygnus OB2 association using parallaxes from the recent second Gaia data release. We find significant line-of-sight substructure within the association, which we quantify using a parametrized model that reproduces the observed parallax distribution. This inference approach is necessary due to the non-linearity of the parallax distance transformation and the asymmetry of the resulting probability distribution. Using a Markov Chain Monte Carlo ensemble sampler and an unbinned maximum likelihood test, we identify two different stellar groups superposed on the association. We find the main Cygnus OB2 group at ∟1760 pc, further away than recent estimates have envisaged, and a foreground group at ∟1350 pc. We also calculate individual membership probabilities and identify outliers as possible non-members of the association.Peer reviewe

    Chandra observations of Cygnus OB2

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    Cygnus OB2 is the nearest example of a massive star forming region, containing over 50 O-type stars and hundreds of B-type stars. We have analyzed two Chandra pointings in Cyg OB2, detecting ~1700 X-ray sources, of which ~1450 are thought to be members of the association. Optical and near-IR photometry has been obtained for ~90% of these sources from recent deep Galactic plane surveys. We have performed isochrone fits to the near-IR color-magnitude diagram, deriving ages of 3.5(+0.75,-1.0) and 5.25(+1.5,-1.0) Myrs for sources in the two fields, both with considerable spreads around the pre-MS isochrones. The presence of a second population in the region, somewhat older than the present-day O-type stars, has been suggested by other authors and fits with the ages derived here. The fraction of sources with inner circumstellar disks (as traced by the K-band excess) is found to be very low, but appropriate for a population of age ~5 Myrs. We measure the stellar mass functions and find a power-law slope of Gamma = -1.09 +/- 0.13, in good agreement with the global mean value estimated by Kroupa. A steepening of the mass function at high masses is observed and we suggest this is due to the presence of the previous generation of stars that have lost their most massive members. Finally, combining our mass function and an estimate of the radial density profile of the association suggests a total mass of Cyg OB2 of ~30,000 Msun, similar to that of many of our Galaxy's most massive star forming regions.Comment: 6 pages, 4 figures, conference proceedings for JENAM 2010: Star Clusters in the Era of Large Surveys, Editors: A.Moitinho and J. Alve

    The massive star population of Cygnus OB2

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    We have compiled a significantly updated and comprehensive census of massive stars in the nearby Cygnus OB2 association by gathering and homogenizing data from across the literature. The census contains 169 primary OB stars, including 52 O-type stars and 3 Wolf–Rayet stars. Spectral types and photometry are used to place the stars in a Hertzsprung–Russell diagram, which is compared to both non-rotating and rotating stellar evolution models, from which stellar masses and ages are calculated. The star formation history and mass function of the association are assessed, and both are found to be heavily influenced by the evolution of the most massive stars to their end states. We find that the mass function of the most massive stars is consistent with a ‘universal’ power-law slope of Γ = 1.3.Peer reviewedFinal Accepted Versio

    Massive stars in the hinterland of the young cluster, Westerlund 2

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    Accepted for publication in MNRAS, 13 July 2018. 16 pages, plus one-page table in an appendix.An unsettled question concerning the formation and distribution of massive stars is whether they must be born in massive clusters and, if found in less dense environments, whether they must have migrated there. With the advent of wide-area digital photometric surveys, it is now possible to identify massive stars away from prominent Galactic clusters without bias. In this study we consider 40 candidate OB stars found in the field around the young massive cluster, Westerlund 2, by Mohr-Smith et al.: these are located inside a box of 1.5 × 1.5 deg 2 and are selected on the basis of their extinctions and K magnitudes.We present VLT/X-shooter spectra of two of the hottest O stars, respectively 11 and 22 arcmin from the centre of Westerlund 2. They are confirmed as O4V stars, with stellar masses likely to be in excess of 40 M ·. Their radial velocities relative to the non-binary reference object, MSP 182, in Westerlund 2 are -29.4 ± 1.7 and -14.4 ± 2.2 km s -1, respectively. Using Gaia DR2 proper motions we find that between 8 and 11 early O/WR stars in the studied region (including the two VLT targets, plus WR 20c and WR 20aa) could have been ejected fromWesterlund 2 in the last one million years. This represents an efficiency of massive-star ejection of up to ~ 25 per cent. On sky, the positions of these stars and their proper motions show a near N-S alignment. We discuss the possibility that these results are a consequence of prior sub-cluster merging combining with dynamical ejection.Peer reviewe

    Effects of higher dietary protein and fiber intakes at breakfast on postprandial glucose, insulin, and 24-H interstitial glucose in overweight adults

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    Dietary protein and fiber independently influence insulin-mediated glucose control. However, potential additive effects are not well-known. Men and women (n = 20; age: 26 ¹ 5 years; body mass index: 26.1 ¹ 0.2 kg/m²; mean ¹ standard deviation) consumed normal protein and fiber (NPNF; NP = 12.5 g, NF = 2 g), normal protein and high fiber (NPHF; NP = 12.5 g, HF = 8 g), high protein and normal fiber (HPNF; HP = 25 g, NF = 2 g), or high protein and fiber (HPHF; HP = 25 g, HF = 8 g) breakfast treatments during four 2-week interventions in a randomized crossover fashion. On the last day of each intervention, meal tolerance tests were completed to assess postprandial (every 60 min for 240 min) serum glucose and insulin concentrations. Continuous glucose monitoring was used to measure 24-h interstitial glucose during five days of the second week of each intervention. Repeated-measures ANOVA was applied for data analyses. The HPHF treatment did not affect postprandial glucose and insulin responses or 24-h glucose total area under the curve (AUC). Higher fiber intake reduced 240-min insulin AUC. Doubling the amount of protein from 12.5 g to 25 g/meal and quadrupling fiber from 2 to 8 g/meal at breakfast was not an effective strategy for modulating insulin-mediated glucose responses in these young, overweight adults.T32 HL116276 - NHLBI NIH HHS; UL1 TR001108 - NCATS NIH HH
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