5,251 research outputs found

    Time Evolution of Entropy in Gravitational Collapse

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    We study the time evolution of the entropy of a collapsing spherical domain wall, from the point of view of an asymptotic observer, by investigating the entropy of the entire system (i.e. domain wall and radiation) and induced radiation alone during the collapse. By taking the difference, we find the entropy of the collapsing domain wall, since this is the object which will form a black hole. We find that for large values of time (times larger than t/Rs≈8t/R_s\approx8), the entropy of the collapsing domain wall is a constant, which is of the same order as the Bekenstein-Hawking entropy.Comment: 9 pages, 6 figure

    Second-order analytic solutions for re-entry trajectories

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76344/1/AIAA-1993-3679-680.pd

    An evaluation of the usage of the career information system of Iowa in secondary subscriber schools as reported by C.I.S.I. contact personnel

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    The Career Information System of Iowa (C.I.S.I.) has been a functioning part of the Department of Public Instruction (D.P.I.) since August 1, 1974. Its primary function has been to provide each school\u27s staff with information and assistance in order that the challenging career education task may be accomplished. (Eilbert & Crowley, 1975, p. 1

    Under the Cover Infant Pose Estimation using Multimodal Data

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    Infant pose monitoring during sleep has multiple applications in both healthcare and home settings. In a healthcare setting, pose detection can be used for region of interest detection and movement detection for noncontact based monitoring systems. In a home setting, pose detection can be used to detect sleep positions which has shown to have a strong influence on multiple health factors. However, pose monitoring during sleep is challenging due to heavy occlusions from blanket coverings and low lighting. To address this, we present a novel dataset, Simultaneously-collected multimodal Mannequin Lying pose (SMaL) dataset, for under the cover infant pose estimation. We collect depth and pressure imagery of an infant mannequin in different poses under various cover conditions. We successfully infer full body pose under the cover by training state-of-art pose estimation methods and leveraging existing multimodal adult pose datasets for transfer learning. We demonstrate a hierarchical pretraining strategy for transformer-based models to significantly improve performance on our dataset. Our best performing model was able to detect joints under the cover within 25mm 86% of the time with an overall mean error of 16.9mm. Data, code and models publicly available at https://github.com/DanielKyr/SMa

    Higher-order analytic solutions for critical cases of ballistic entry

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77179/1/AIAA-1996-3425-378.pd

    Performance of an Operating High Energy Physics Data Grid: D0SAR-Grid

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    The D0 experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of D0 collaborators poses further serious difficulties for optimal use of human and computing resources. These difficulties will exacerbate in future high energy physics experiments, like the LHC. The computing grid has long been recognized as a solution to these problems. This technology is being made a more immediate reality to end users in D0 by developing a grid in the D0 Southern Analysis Region (D0SAR), D0SAR-Grid, using all available resources within it and a home-grown local task manager, McFarm. We will present the architecture in which the D0SAR-Grid is implemented, the use of technology and the functionality of the grid, and the experience from operating the grid in simulation, reprocessing and data analyses for a currently running HEP experiment.Comment: 3 pages, no figures, conference proceedings of DPF04 tal

    Early intervention for stigma towards mental illness? Promoting positive attitudes towards severe mental illness in primary school children

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    Purpose Stigma towards severe mental illness (SMI) is widespread, exacerbating mental health problems, and impacting on help-seeking and social inclusion. Anti-stigma campaigns are meeting with success, but results are mixed. Earlier intervention to promote positive mental health literacy rather than challenge stigma, may show promise, but little is known about stigma development or interventions in younger children. This study will investigate (i) children’s knowledge, attitudes and behaviour towards SMI and (ii) whether we can positively influence children’s attitudes before stigma develops. Design/methodology/approach A cross sectional study investigated mental health schema in 7-11 year olds. An experimental intervention investigated whether an indirect contact story-based intervention in 7-8 year olds led to more positive mental health schema. Findings: Young children’s schema were initially positive, and influenced by knowledge and contact with mental illness & intergroup anxiety, but were more stigmatising in older girls as intergroup anxiety increased. The indirect contact intervention was effective in promoting positive mental health schema, partially mediated by knowledge. Social Implications: Intervening early to shape concepts of mental illness more positively, as they develop in young children, may represent a more effective strategy than attempting to challenge and change mental health stigma once it has formed in adolescents and adults. Originality/Value: This study is the first to investigate an intervention targeted at the prevention of stigma towards severe mental illness, in young children, at the point that stigma is emerging

    Effect of membrane character and solution chemistry on microfiltration performance

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    To help understand and predict the role of natural organic matter (NOM) in the fouling of low-pressure membranes, experiments were carried out with an apparatus that incorporates automatic backwashing and long filtration runs. Three hollow fibre membranes of varying character were included in the study, and the filtration of two different surface waters was compared. The hydrophilic membrane had greater flux recovery after backwashing than the hydrophobic membranes, but the efficiency of backwashing decreased at extended filtration times. NOM concentration of these waters (7.9 and 9.1 mg/L) had little effect on the flux of the membranes at extended filtration times, as backwashing of the membrane restored the flux to similar values regardless of the NOM concentration. The solution pH also had little effect at extended filtration times. The backwashing efficiency of the hydrophilic membrane was dramatically different for the two waters, and the presence of colloid NOM alone could not explain these differences. It is proposed that colloidal NOM forms a filter cake on the surface of the membranes and that small molecular weight organics that have an adsorption peak at 220 nm but not 254 nm were responsible for “gluing” the colloids to the membrane surface. Alum coagulation improved membrane performance in all instances, and this was suggested to be because coagulation reduced the concentration of “glue” that holds the organic colloids to the membrane surface

    Individual component analysis of the multi-parametric cardiovascular magnetic resonance protocol in the CE-MARC trial

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    Background: The CE-MARC study assessed the diagnostic performance investigated the use of cardiovascular magnetic resonance (CMR) in patients with suspected coronary artery disease (CAD). The study used a multi-parametric CMR protocol assessing 4 components: i) left ventricular function; ii) myocardial perfusion; iii) viability (late gadolinium enhancement (LGE)) and iv) coronary magnetic resonance angiography (MRA). In this pre-specified CE-MARC sub-study we assessed the diagnostic accuracy of the individual CMR components and their combinations. Methods: All patients from the CE-MARC population (n = 752) were included using data from the original blinded-read. The four individual core components of the CMR protocol was determined separately and then in paired and triplet combinations. Results were then compared to the full multi-parametric protocol. Results: CMR and X-ray angiography results were available in 676 patients. The maximum sensitivity for the detection of significant CAD by CMR was achieved when all four components were used (86.5 %). Specificity of perfusion (91.8 %), function (93.7 %) and LGE (95.8 %) on its own was significantly better than specificity of the multi-parametric protocol (83.4 %) (all P < 0.0001) but with the penalty of decreased sensitivity (86.5 % vs. 76.9 %, 47.4 % and 40.8 % respectively). The full multi-parametric protocol was the optimum to rule-out significant CAD (Likelihood Ratio negative (LR-) 0.16) and the LGE component alone was the best to rue-in CAD (LR+ 9.81). Overall diagnostic accuracy was similar with the full multi-parametric protocol (85.9 %) compared to paired and triplet combinations. The use of coronary MRA within the full multi-parametric protocol had no additional diagnostic benefit compared to the perfusion/function/LGE combination (overall accuracy 84.6 % vs. 84.2 % (P = 0.5316); LR- 0.16 vs. 0.21; LR+ 5.21 vs. 5.77). Conclusions: From this pre-specified sub-analysis of the CE-MARC study, the full multi-parametric protocol had the highest sensitivity and was the optimal approach to rule-out significant CAD. The LGE component alone was the optimal rule-in strategy. Finally the inclusion of coronary MRA provided no additional benefit when compared to the combination of perfusion/function/LGE. Trial registration: Current Controlled Trials ISRCTN77246133

    Transmission efficiency and noise, vibration and harshness refinement of differential hypoid gear pairs

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    This article presents a combined multi-body dynamics and lubricated contact mechanics model of vehicular differential hypoid gear pairs, demonstrating the transient nature of transmission efficiency and noise, vibration and harshness performance under various driving conditions. The contact of differential hypoid gears is subjected to mixed thermo-elastohydrodynamic regime of lubrication. The coefficient of friction is obtained using an analytical approach for non-Newtonian lubricant shear and supplemented by boundary interactions for thin films. Additionally, road data and aerodynamic effects are used in the form of resisting torque applied to the output side of the gear pair. Sinusoidal engine torque variation is also included to represent engine order torsional input resident on the pinion gear. Analysis results are presented for New European Driving Cycle transience from low-speed city driving condition in second gear to steady-state cruising in fourth gear for a light truck. It is shown that the New European Driving Cycle captures the transmission efficiency characteristics of the differential hypoid gear pair under worst case scenario, with its underlying implications for fuel efficiency and emissions. However, it fails to address the other key attribute, being the noise, vibration and harshness performance. In the case of hypoid gears, the resultant noise, vibration and harshness characteristics can be particularly annoying. It is concluded that broader transient manoeuvres encompassing New European Driving Cycle are required for assessment, in order to obtain a balanced approach for transmission efficiency and noise, vibration and harshness performance. This approach is undertaken in this article, which is not hitherto reported in the literature
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