22,616 research outputs found

    Kingmakers or Cheerleaders? Party Power and the Causal Effects of Endorsements

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    When parties make endorsements in primary elections, does the favored candidate receive a real boost in his or her vote share, or do parties simply pick the favorites who are already destined to win? To answer this question, we draw on two research designs aimed at isolating the causal effect of Democratic Party endorsements in California’s 2012 primary election. First, we conduct a survey experiment in which we randomly assign a party endorsement, holding all other aspects of a candidate’s background and policy positions constant. Second, we use a unique dataset to implement a regression discontinuity analysis of electoral trends by comparing the vote shares captured by candidates who barely won or barely lost the internal party endorsement contest. We find a constellation of evidence suggesting that endorsements do indeed matter, although this effect appears to be contingent upon the type of candidate and voter: endorsements matter most for candidates in their party’s mainstream, and for voters who identify with that party and for independents. The magnitude of their impact is dramatically smaller than might be estimated from research designs less attuned to recent advances in causal inference

    Study of thermal insulation for airborne liquid hydrogen fuel tanks

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    A concept for a fail-safe thermal protection system was developed. From screening tests, approximately 30 foams, adhesives, and reinforcing fibers using 0.3-meter square liquid nitrogen cold plate, CPR 452 and Stafoam AA1602, both reinforced with 10 percent by weight of 1/16 inch milled OCF Style 701 Fiberglas, were selected for further tests. Cyclic tests with these materials in 2-inch thicknesses bonded on a 0.6-meter square cold plate with Crest 7410 adhesive systems, were successful. Zero permeability gas barriers were identified and found to be compatible with the insulating concept

    Decision-making for unmanned aerial vehicle operation in icing conditions

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    With the increased use of unmanned aerial systems (UAS) for civil and commercial applications, there is a strong demand for new regulations and technology that will eventually permit for the integration of UAS in unsegregated airspace. This requires new technology to ensure sufficient safety and a smooth integration process. The absence of a pilot on board a vehicle introduces new problems that do not arise in manned flight. One challenging and safety-critical issue is flight in known icing conditions. Whereas in manned flight, dealing with icing is left to the pilot and his appraisal of the situation at hand; in unmanned flight, this is no longer an option and new solutions are required. To address this, an icing-related decision-making system (IRDMS) is proposed. The system quantifies in-flight icing based on changes in aircraft performance and measurements of environmental properties, and evaluates what the effects on the aircraft are. Based on this, it determines whether the aircraft can proceed, and whether and which available icing protection systems should be activated. In this way, advice on an appropriate response is given to the operator on the ground, to ensure safe continuation of the flight and avoid possible accidents

    A simple interpretation of quantum mirages

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    In an interesting new experiment the electronic structure of a magnetic atom adsorbed on the surface of Cu(111), observed by STM, was projected into a remote location on the same surface. The purpose of the present paper is to interpret this experiment with a model Hamiltonian, using ellipses of the size of the experimental ones, containing about 2300 atoms. The charge distribution for the different wavefunctions is analyzed, in particular, for those with energy close to the Fermi energy of copper Ef. Some of them show two symmetric maxima located on the principal axis of the ellipse but not necessarily at the foci. If a Co atom is adsorbed at the site where the wavefunction with energy EFE_F has a maximum and the interaction is small, the main effect of the adsorbed atom will be to split this particular wavefunction in two. The total charge density will remain the same but the local density of states will present a dip at Ef at any site where the charge density is large enough. We relate the presence of this dip to the observation of quantum mirages. Our interpretation suggests that other sites, apart from the foci of the ellipses, can be used for projecting atomic images and also indicates the conditions for other non magnetic adsorbates to produce mirages.Comment: 3 pages, 3 Fig

    Higher physical fitness levels are associated with less language decline in healthy ageing

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    Healthy ageing is associated with decline in cognitive abilities such as language. Aerobic fitness has been shown to ameliorate decline in some cognitive domains, but the potential benefits for language have not been examined. In a cross-sectional sample, we investigated the relationship between aerobic fitness and tip-of-the-tongue states. These are among the most frequent cognitive failures in healthy older adults and occur when a speaker knows a word but is unable to produce it. We found that healthy older adults indeed experience more tip-of-the-tongue states than young adults. Importantly, higher aerobic fitness levels decrease the probability of experiencing tip-of-the-tongue states in healthy older adults. Fitness-related differences in word finding abilities are observed over and above effects of age. This is the first demonstration of a link between aerobic fitness and language functioning in healthy older adults

    Reduction in jejunal fluid absorption in vivo through distension and cholinergic stimulation not attributable to enterocyte secretion

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    Jejunal fluid absorption in vivo was reduced by distension and by hydrostatic pressure and further declined on adding E. coli STa enterotoxin but no net fluid secretion was detected. Luminal atropine reduced pressure mediated reductions in fluid absorption to normal values but intravenous hexamethonium was without effect. A neural component to inhibition of absorption by pressure (though not stretch) may be mediated by axon reflexes within cholinergic neurons.Perfusion of cholinergic compounds also reduced net fluid absorption but did not cause secretion. In order to show that these actions were not secretory processes stimulated by cholinergic compounds that offset normal rates of absorption, these compounds were tested for their ability to cause net secretion in loops that were perfused with solutions in which choline substituted for sodium ion. In addition, these perfusates additionally contained E. coli STa enterotoxin or EIPA (ethyl-isopropyl-amiloride) to minimize absorption.In these circumstances, where it might be expected to do so if it were acting through a secretory rather than an absorptive mechanism, carbachol did not cause net fluid secretion. Cholinergic stimulation and pressure induced distension are thought to reduce net fluid absorption through inducing secretion but are found only to reduce fluid absorption.In conclusion, distension and cholinergic stimulation of the small intestine are two further circumstances in which fluid secretion is assumed to explain their action on fluid movement, as required by the enterocyte secretion model of secretion but, which like STa enterotoxin, instead are only able to reduce fluid absorption. This casts further doubt on the widespread validity of the enterocyte secretion model for fluid appearance in the lumen in diarrhoeal diseases

    A note on the existence of soliton solutions in the Chern-Simons-CP(1) model

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    We study a gauged Chern-Simons-CP(1) system. We show that contrary to previous claims the model in the absences of a potential term cannot support finite size soliton solution in R2R^2.Comment: 12 pages, 5 figure

    Flourishing Mindfully: Mindfulness Moderates the Associations of Stress, Psychopathology, and Grit with Flourishing

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    Dispositional mindfulness includes greater present-moment attention and lower maladaptive responses to experience. Thus, theory proposes that dispositional mindfulness may be related to functional flourishing through greater engagement in valued activities, as well as less reactivity to the states that interfere with them (e.g., stress). This cross-sectional study tested the concurrent relationships proposed in these hypotheses. A random sample of 394 undergraduate students completed a survey that included the Cognitive and Affective Mindfulness Scale Revised, the Perceived Stress Scale, The Patient Health Questionnaire for Anxiety and Depression 4, the Short Grit Scale, and the Flourishing Scale. We used multiple linear regression to analyze a single combined model in which functional flourishing was predicted by mindfulness, stress, anxiety/depression, grit’s subfactors, and the interactions of mindfulness with each predictor. Higher mindfulness was significantly associated with higher functional flourishing. Higher mindfulness also significantly moderated the influence of stress and anxiety/depression on flourishing, weakening their negative associations. Lastly, mindfulness significantly strengthened the positive association between flourishing and perseverance, a grit subfactor. As theorized, mindfulness may be 1) associated with higher functional flourishing, 2) weaken the negative influence of aversive experiences on flourishing, and 3) strengthen the positive influence of beneficial traits on flourishing

    Heath beliefs of UK South Asians related to lifestyle diseases: a review of qualitative literature.

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    OBJECTIVE: To review available qualitative evidence in the literature for health beliefs and perceptions specific to UK South Asian adults. Exploring available insight into the social and cultural constructs underlying perceptions related to health behaviours and lifestyle-related disease. METHODS: A search of central databases and ethnic minority research groups was augmented by hand-searching of reference lists. For included studies, quality was assessed using a predetermined checklist followed by metaethnography to synthesise the findings, using both reciprocal translation and line-of-argument synthesis to look at factors impacting uptake of health behaviours. RESULTS: A total of 10 papers varying in design and of good quality were included in the review. Cultural and social norms strongly influenced physical activity incidence and motivation as well as the ability to engage in healthy eating practices. CONCLUSIONS: These qualitative studies provide insight into approaches to health among UK South Asians in view of their social and cultural norms. Acknowledgement of their approach to lifestyle behaviours may assist acceptability of interventions and delivery of lifestyle advice by health professionals
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