1,450 research outputs found

    Direct and indirect effects of mood on risk decision making in safety-critical workers

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    The study aimed to examine the direct influence of specific moods (fatigue, anxiety, happiness) on risk in safety-critical decision making. It further aimed to explore indirect effects, specifically, the potential mediating effects of information processing assessed using a goodness-of-simulation task. Trait fatigue and anxiety were associated with an increase in risk taking on the Safety-Critical Personal Risk Inventory (S-CPRI), however the effect of fatigue was partialled out by anxiety. Trait happiness, in contrast was related to less risky decision making. Findings concerning the ability to simulate suggest that better simulators made less risky decisions. Anxious workers were generally less able to simulate. It is suggested that in this safety-critical environment happiness had a direct effect on risk decision making while the effect of trait anxiety was mediated by goodness-of-simulation

    Schwinger model on a half-line

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    We study the Schwinger model on a half-line in this paper. In particular, we investigate the behavior of the chiral condensate near the edge of the line. The effect of the chosen boundary condition is emphasized. The extension to the finite temperature case is straightforward in our approach.Comment: 4 pages, no figure. Final version to be published on Phys. Rev.

    Finite Temperature Correlators in the Schwinger Model

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    We discuss the correlation function of hadronic currents in the Schwinger model at finite temperature TT. We explicitly construct the retarded correlator in real time and obtain analytical results for the Euclidean correlator on a torus. Both constructions lead to the same finite temperature spectral function. The spatial screening lengths in the mesonic channels are related to the dynamical meson mass m=e/Ï€m=e/\sqrt{\pi} and not 2Ï€T2\pi T even in the infinite temperature limit. The relevance of our results for the finite temperature problem in four dimensions is discussed.Comment: in LATEX, 30 pages; two figures available on request from the authors; USITP-93-19, SUNY-NTG-43, (explanations to the figures have been clarified

    An XMM-Newton spatially-resolved study of metal abundance evolution in distant galaxy clusters

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    We present an XMM-Newton analysis of the X-ray spectra of 39 clusters of galaxies at 0.4<z<1.4, covering a temperature range of 1.5<=kT<=11 keV. We performed a spatially resolved spectral analysis to study how the abundance evolves with redshift not only through a single emission measure performed on the whole cluster but also spatially resolving the cluster emission. We do not observe a statistically significant (>2sigma) abundance evolution with redshift. The most significant deviation from no evolution (90% c.l.) is observed in the emission from the whole cluster (r<0.6r500), that could be parametrized as Z=A*(1+z)^(-0.8+/-0.5). Dividing the emission in 3 radial bins, no significant evidence of abundance evolution could be observed fitting the data with a power-law. A substantial agreement with measures presented in previous works is found. The error-weighted mean of the spatially resolved abundances in 3 redshift bins is consistent to be constant with z. Although the large error bars in the measure of the weighted-mean abundance prevent us from claiming any significant spatially resolved evolution, the trend with z in the 0.15-0.4r500 radial bin complements nicely the measures of Maughan et al., and broadly agrees with theoretical predictions. We also found that the data points derived from the spatially resolved analysis are well fitted by the relation Z(r,z)=Z0*(1+(r/0.15r500)^2)^(-a)*((1+z)/1.6)^(-gamma), showing a significant negative trend of Z with the radius and no significant evolution with the redshift. The present study is the first attempt made to spatially resolve the evolution of abundance with redshift. However, the sample size and the low statistics associated with most of the clusters in the sample prevents us to draw any statistically significant conclusion on the different evolutionary path that the different regions of the clusters may have traversed.Comment: 12 pages, 8 figures, A&A in press, minor changes (language editing

    Local Starbursts in a Cosmological Context

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    In this contribution I introduce some of the major issues that motivate the conference, with an emphasis on how starbursts fit into the ``big picture''. I begin by defining starbursts in several different ways, and discuss the merits and limitations of these definitions. I will argue that the most physically useful definition of a starburst is its ``intensity'' (star formation rate per unit area). This is the most natural parameter to compare local starbursts with physically similar galaxies at high redshift, and indeed I will argue that local starbursts are unique laboratories to study the processes at work in the early universe. I will describe how NASA's GALEX mission has uncovered a rare population of close analogs to Lyman Break Galaxies in the local universe. I will then compare local starbursts to the Lyman-Break and sub-mm galaxies high redshift populations, and speculate that the multidimensional ``manifold'' of starbursts near and far can be understood largely in terms of the Schmidt/Kennicutt law and galaxy mass-metallicity relation. I will briefly summarize he properties of starburst-driven galactic superwinds and their possible implications for the evolution of galaxies and the IGM. These complex multiphase flows are best studied in nearby starbursts, where we can study the the hot X-ray gas that contains the bulk of the energy and newly produced metals.Comment: Proceedings of the Conference "Starbursts: Fropm 30 Doradus to Lyman Break Galaxies

    Elevated arousal at time of decision-making is not the arbiter of risk avoidance in chickens

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    The somatic marker hypothesis proposes that humans recall previously experienced physiological responses to aid decision-making under uncertainty. However, little is known about the mechanisms used by non-human animals to integrate risk perception with predicted gains and losses. We monitored the behaviour and physiology of chickens when the choice between a high-gain (large food quantity), high-risk (1 in 4 probability of receiving an air-puff) option (HGRAP) or a low-gain (small food quantity), no-risk (of an air-puff) (LGNAP) option. We assessed when arousal increased by considering different stages of the decision-making process (baseline, viewing, anticipation, reward periods) and investigated whether autonomic responses influenced choice outcome both immediately and in the subsequent trial. Chickens were faster to choose and their heart-rate significantly increased between the viewing and anticipation (post-decision, pre-outcome) periods when selecting the HGRAP option. This suggests that they responded physiologically to the impending risk. Additionally, arousal was greater following a HGRAP choice that resulted in an air-puff, but this did not deter chickens from subsequently choosing HGRAP. In contrast to human studies, we did not find evidence that somatic markers were activated during the viewing period, suggesting that arousal is not a good measure of avoidance in non-human animals
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