131 resultados para Vortex matter
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The most influential current idea in the theory of conflict management concerns the design features and supposed superior outcomes of conflict management systems combining interest-based and rights-based practices for resolving conflict in organizations. Yet much of the literature in the area is highly prescriptive and draws heavily either on exemplary case studies or descriptive data. Using focus groups of HR practitioners and experts in conflict resolution to develop a questionnaire covering the main conflict management practices associated with the theory of conflict management systems, the study analyzes data from a survey of firms in the Republic of Ireland to examine quantitatively the effects of conflict management systems on organizational outcomes. While proactive line management and supervisory engagement in conflict resolution as a key dimension of conflict management systems is found to be positively associated with a range of organizational outcomes, no evidence is found for the kind of system effects proposed in the theoretical and prescriptive literature. © 2012 Wiley Periodicals, Inc.
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Building on a body of previous research by the author and colleagues in relation to multiple adverse childhood experiences (MACE), this paper addresses the question of ‘why multiples matter’ in relation to issues of cumulative adversity. Illustrative evidence is drawn from three research domains, epidemiology, multiple services use and child maltreatment to demonstrate the collective weight of evidence to suggest a targeting of those children and families experiencing multiple adversities to diminish the effects of such adversities realised across the life-course. Whilst the history of previous largely unsuccessful attempts to widen the range of children prioritised for intervention by child and family social workers might lead to pessimism in relation to their ability to respond to a MACE informed public health agenda, there are clear possibilities for developing agency structures, assessment tools and social work practices directed toward meeting the needs of those sub populations already prioritised by social workers: namely Children in Need, Children in need of Protection and Looked after Children.
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This paper describes an experimental investigation into the effect of restricting the vortex-induced vibrations of a spring-mounted rigid cylinder by means of stiff mechanical endstops. Cases of both asymmetric and symmetric restraint are investigated. Results show that limiting the amplitude of the vibrations strongly affects the dynamics of the cylinder, particularly when the offset is small. Fluid-structure interaction is profoundly affected, and the well-known modes of vortex shedding observed with a linear elastic system are modified or absent. There is no evidence of lock-in, and the dominant impact frequency corresponds to a constant Strouhal number of 0.18. The presence of an endstop on one side of the motion can lead to large increases in displacements in the opposite direction. Attention is also given to the nature of the developing chaotic motion, and to impact velocities, which in single-sided impacts approach the maximum velocity of a cylinder with linear compliance undergoing VIV at lock-in. With symmetrical endstops, impact velocities were about one-half of this. Lift coefficients are computed from an analysis of the cylinder’s motion between impacts.
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Objectives: To explore the associations of working hours ( paid, domestic, commuting, and total) with sickness absence, and to examine whether these associations vary according to the level of employee control over daily working hours.
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Using direct numerical magneto-hydrodynamic (MHD) simulations, we demonstrate the evidence of two physically different types of vortex motions in the solar photosphere. Baroclinic motions of plasma in non-magnetic granules are the primary source of vorticity in granular regions of the solar photosphere, however, there is a significantly more efficient mechanism of vorticity production in strongly magnetised intergranular lanes. These swirly motions of plasma in intergranular magnetic field concentrations could be responsible for the generation of different types of MHD wave modes, for example, kink, sausage and torsional Alfven waves. These waves could transport a relevant amount of energy from the lower solar atmosphere and contribute to coronal plasma heating.
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This paper compares the Random Regret Minimization and the Random Utility Maximization models for determining recreational choice. The Random Regret approach is based on the idea that, when choosing, individuals aim to minimize their regret – regret being defined as what one experiences when a non-chosen alternative in a choice set performs better than a chosen one in relation to one or more attributes. The Random Regret paradigm, recently developed in transport economics, presents a tractable, regret-based alternative to the dominant choice paradigm based on Random Utility. Using data from a travel cost study exploring factors that influence kayakers’ site-choice decisions in the Republic of Ireland, we estimate both the traditional Random Utility multinomial logit model (RU-MNL) and the Random Regret multinomial logit model (RR-MNL) to gain more insights into site choice decisions. We further explore whether choices are driven by a utility maximization or a regret minimization paradigm by running a binary logit model to examine the likelihood of the two decision choice paradigms using site visits and respondents characteristics as explanatory variables. In addition to being one of the first studies to apply the RR-MNL to an environmental good, this paper also represents the first application of the RR-MNL to compute the Logsum to test and strengthen conclusions on welfare impacts of potential alternative policy scenarios.
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Experiments were performed in which intense laser pulses (up to 9x10(19) W/cm(2)) were used to irradiate very thin (submicron) mass-limited aluminum foil targets. Such interactions generated high-order harmonic radiation (greater than the 25th order) which was detected at the rear of the target and which was significantly broadened, modulated, and depolarized because of passage through the dense relativistic plasma. The spectral modifications are shown to be due to the laser absorption into hot electrons and the subsequent sharply increasing relativistic electron component within the dense plasma.
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Experimental demonstration of negative ion acceleration to MeV energies from sub-micron size droplets of water spray irradiated by ultra-intense laser pulses is presented. Thanks to the specific target configuration and laser parameters, more than 109 negative ions per steradian solid angle in 5% energy bandwidth are accelerated in a stable and reliable manner. To our knowledge, by virtue of the ultra-short duration of the emission, this is by far the brightest negative ion source reported. The data also indicate the existence of beams of neutrals with at least similar numbers and energies.