1,439 research outputs found
Neutrino flavor mixing with moments
The successful transition from core-collapse supernova simulations using
classical neutrino transport to simulations using quantum neutrino transport
will require the development of methods for calculating neutrino flavor
transformations that mitigate the computational expense. One potential approach
is the use of angular moments of the neutrino field, which has the added appeal
that there already exist simulation codes which make use of moments for
classical neutrino transport. Evolution equations for quantum moments based on
the quantum kinetic equations can be straightforwardly generalized from the
evolution of classical moments based on the Boltzmann equation. We present an
efficient implementation of neutrino transformation using quantum angular
moments in the free streaming, spherically symmetric bulb model. We compare the
results against analytic solutions and the results from more exact multi-angle
neutrino flavor evolution calculations. We find that our moment-based methods
employing scalar closures predict, with good accuracy, the onset of collective
flavor transformations seen in the multi-angle results. However in some
situations they overestimate the coherence of neutrinos traveling along
different trajectories. More sophisticated quantum closures may improve the
agreement between the inexpensive moment-based methods and the multi-angle
approach.Comment: Accepted in Physical Review
Money and mental wellbeing : a longitudinal study of medium-sized lottery wins
One of the famous questions in social science is whether money makes people happy. We offer new evidence by using longitudinal data on a random sample of Britons who receive medium-sized lottery wins of between ÂŁ1000 and ÂŁ120,000 (that is, up to approximately US$ 200,000). When compared to two control groups â one with no wins and the other with small wins â these individuals go on eventually to exhibit significantly better psychological health. Two years after a lottery win, the average measured improvement in mental wellbeing is 1.4 GHQ points
âWe have to wait in a queue for our turn quite a bitâ Examining childrenâs physical activity during primary physical education lessons
The overall purpose of this study was to examine childrenâs physical activity (PA) during primary physical education (PE). This was achieved through the following two research objectives: (1) to measure childrenâs PA, lesson context and teacher promotion of PA during PE lessons; and (2) to explore teachersâ and childrenâs perspectives on PA levels during PE lessons. Evidence suggests that childrenâs PA during PE is below recommended levels and further research is required to understand the reasons why. Through a mixed method design, 138 children were observed using the System for Observing Fitness and Instruction Time, 80 children participated in group interviews, and 13 teachers were interviewed, across three primary schools in England. Findings indicated that the mean percentage of lesson time allocated to moderate to vigorous PA (MVPA) was 42.4% and the average lesson length was 35.3 minutes. Qualitative themes identified were: âknowledge and beliefsâ; âteacher pedagogyâ; and âteacher developmentâ. The findings indicate that a change in perspective is needed, which includes a focus on PA during primary PE lessons. Intervention work is required that targets teachersâ knowledge and beliefs towards PE along with the development of effective teaching strategies. However, this needs to be grounded in an ecological approach which will allow researchers and schools to target the various levels of influence. It is strongly recommended that interventions are grounded in behaviour change theory, as this study indicates that sharing knowledge about pedagogical strategies to increase childrenâs MVPA does not necessarily produce changes in teachersâ behaviours
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Comparison of four methods for assessing the importance of attitudinal beliefs: An international Delphi study in intensive care settings
Objectives: Behaviour change interventions often target âimportantâ beliefs. The literature proposes four methods for assessing importance of attitudinal beliefs: elicitation frequency, importance ratings, and strength of prediction (bivariate and multivariate). We tested congruence between these methods in a Delphi study about selective decontamination of the digestive tract (SDD). SDD improves infection rates among critically ill patients, yet uptake in intensive care units is low internationally.
Methods: A Delphi study involved three iterations (âroundsâ). Participants were 105 intensive care clinicians in the United Kingdom, Canada, and Australia/New Zealand. In Round 1, semiâstructured interviews were conducted to elicit beliefs about delivering SDD. In Rounds 2 and 3, participants completed questionnaires, rating agreement and importance for each beliefâstatement (9âpoint Likert scales). Belief importance was assessed using elicitation frequency, mean importance ratings, and prediction of global attitude (Pearson's correlations; betaâweights). Correlations between indices were computed.
Results: Participants generated 14 attitudinal beliefs. Indices had adequate variation (frequencies: 4â94, mean importance ratings: 4.93â8.00, Pearson's correlations: ±0.09 to ±0.54, betaâweights: ±0.01 to ±0.30). SDD increases antibiotic resistance was the most important belief according to three methods and was ranked second by betaâweights (behind Overall, SDD benefits patients to whom it is delivered). Spearman's correlations were significant for importance ratings with frequencies and correlations. However, other indices were unrelated. The top four beliefs differed according to the measure used.
Conclusions: Results provided evidence of congruence across three methods for assessing belief importance. Betaâweights were unrelated to other indices, suggesting that they may not be appropriate as the sole method
The SDO Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time
The Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program began as a series of discrete efforts implemented by each of the instrument teams and has evolved into a well-rounded program with a full suite of national and international programs. The SDO E/PO team has put forth much effort in the past few years to increase our cohesiveness by adopting common goals and increasing the amount of overlap between our programs. In this paper, we outline the context and overall philosophy for our combined programs, present a brief overview of all SDO E/PO programs along with more detailed highlight of a few key programs, followed by a review of our results up to date. Concluding is a summary of the successes, failures, and lessons learned that future missions can use as a guide, while further incorporating their own content to enhance the public's knowledge and appreciation of NASA?s science and technology as well as its benefit to society
The Solar Dynamics Observatory (SDO) Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time
We outline the context and overall philosophy for the combined Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program, present a brief overview of all SDO E/PO programs along with more detailed highlights of a few key programs, followed by a review of our results to date, conclude a summary of the successes, failures, and lessons learned, which future missions can use as a guide, while incorporating their own content to enhance the public's knowledge and appreciation of science and technology as well as its benefit to society
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Vegetable variety trials 2010
This publication is a compilation of vegetable variety trial notes from field trials conducted in summer 2010. It contains information on a wide variety of vegetables and focuses on quality characteristics and adaptability to western Oregon.Revised April 2011. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalogKeywords: vegetable, agriculture, variety trial, gardeningKeywords: vegetable, agriculture, variety trial, gardenin
Islet ÎČ-Cells Deficient in Bcl-xL Develop but Are Abnormally Sensitive to Apoptotic Stimuli
OBJECTIVE: Bcl-xL is an antiapoptotic member of the Bcl-2 family of proteins and a potent regulator of cell death. We investigated the importance of Bcl-xL for beta-cells by deleting the Bcl-x gene specifically in beta-cells and analyzing their survival in vivo and in culture. RESEARCH DESIGN AND METHODS: Islets with beta-cells lacking the Bcl-x gene were assessed in vivo by histology and by treatment of mice with low-dose streptozotocin (STZ). Islets were isolated by collagenase digestion and treated in culture with the apoptosis inducers staurosporine, thapsigargin, gamma-irradiation, proinflammatory cytokines, or Fas ligand. Cell death was assessed by flow cytometric analysis of subgenomic DNA. RESULTS: Bcl-xL-deficient beta-cells developed but were abnormally sensitive to apoptosis induced in vivo by low-dose STZ. Although a small proportion of beta-cells still expressed Bcl-xL, these did not have a survival advantage over their Bcl-xL-deficient neighbors. Islets appeared normal after collagenase isolation and whole-islet culture. They were, however, abnormally sensitive in culture to a number of different apoptotic stimuli including cytotoxic drugs, proinflammatory cytokines, and Fas ligand. CONCLUSIONS: Bcl-xL expression in beta-cells is dispensible during islet development in the mouse. Bcl-xL is, however, an important regulator of beta-cell death under conditions of synchronous stress. Bcl-xL expression at physiological levels may partially protect beta-cells from apoptotic stimuli, including apoptosis because of mediators implicated in type 1 diabetes and death or degeneration of transplanted islets
Scientific publishing and the reading of science in nineteenth-century Britain: a historiographical survey and guide to sources
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It is now generally accepted that both the conception and practices of natural enquiry in the Western tradition underwent a series of profound developments in the late eighteenth and early nineteenth centuryâdevelopments which have been variously characterized as a âsecond scientific revolutionâ and, much more tellingly, as the âinvention of scienceâ. As several authors have argued, moreover, a crucial aspect of this change consisted in the distinctive audience relations of the new sciences. While eighteenth-century natural philosophy was distinguished by an audience relation in which, as William Whewell put it, âa large and popular circle of spectators and amateurs [felt] themselves nearly upon a level, in the value of their trials and speculations, with more profound thinkersâ, the science which was invented in the late eighteenth and early nineteenth century was, as Simon Schaffer has argued, marked by the âemergence of disciplined, trained cadres of research scientistsâ clearly distinguished from a wider, exoteric public. Similarly, Jan Golinski argues that the âemergence of new instrumentation and a more consolidated social structure for the specialist communityâ for early nineteenth-century chemistry was intimately connected with the transformation in the role of its public audience to a condition of relative passivity. These moves were underpinned by crucial epistemological and rhetorical shiftsâfrom a logic of discovery, theoretically open to all, to a more restrictive notion of discovery as the preserve of scientific âgeniusâ, and from an open-ended philosophy of âexperienceâ to a far more restrictive notion of disciplined âexpertiseâ. Both of these moves were intended to do boundary work, restricting the community active in creating and validating scientific knowledge, and producing a passive public
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