Scattering a pulse from a chaotic cavity: Transitioning from algebraic to exponential decay

The ensemble averaged power scattered in and out of lossless chaotic cavities decays as a power law in time for large times. In the case of a pulse with a finite duration, the power scattered from a single realization of a cavity closely tracks the power law ensemble decay initially, but eventually transitions to an exponential decay. In this paper, we explore the nature of this transition in the case of coupling to a single port. We find that for a given pulse shape, the properties of the transition are universal if time is properly normalized. We define the crossover time to be the time at which the deviations from the mean of the reflected power in individual realizations become comparable to the mean reflected power. We demonstrate numerically that, for randomly chosen cavity realizations and given pulse shapes, the probability distribution function of reflected power depends only on time, normalized to this crossover time.Comment: 23 pages, 5 figure

Business valuation in bankruptcy : a nonhauthoritative guide; Consulting services practice aid, 02-1

https://egrove.olemiss.edu/aicpa_news/1167/thumbnail.jp

Libby Amphibole Contamination in Tree Bark Surrounding Historical Vermiculite Processing Facilities

Over a 70-year period, a mine near Libby, MT supplied nearly 80% of the world’s vermiculite. Raw vermiculite, which was contaminated with naturally occurring amphibole in veins throughout the deposit, was shipped to processing sites throughout the United States for exfoliation. In this pilot study, tree bark samples were collected near processing facili-ties in Spokane, WA, Santa Ana, CA, Newark, CA, and Phoenix, AZ in an effort to determine if areas surrounding these facilities are today contaminated with Libby amphibole asbestos (AA). From areas surrounding each of the four his-torical processing sites, Libby AA was detected in a subset of the bark samples. At the Santa Ana, Newark and Phoenix facilities, actinolite-tremolite and other high Fe Ca-bearing amphibole were also measured from the bark samples. In addition, chrysotile was frequently measured in samples collected from each of the sites. From the results of this pilot study, it is evident that tree bark can serve as reservoirs of asbestos, and indicators of past and current contamination. These data also suggest that areas outside of these historical processing facilities may today have some level of existing contamination resulting from the operation of these facilities

Working conditions, work-life conflict and wellbeing in UK prison officers: the role of affective rumination and detachment

Although prison officers experience the working conditions associated with work-life conflict, little research has explored this issue. This study draws upon the work-home resources model (ten Brummelhuis & Bakker, 2012) to investigate relationships between working conditions (demands and experiences of aggression) and time-based, strain-based and behavior-based work-life conflict in UK prison officers (n = 1,682). Associations between working conditions, work-life conflict, and emotional exhaustion were also examined. Two recovery behaviors (affective rumination and detachment) were considered as potential moderators of associations between working conditions and emotional exhaustion. High levels of all work-life conflict dimensions were found which were related to working conditions and emotional exhaustion. Some evidence was found that higher rumination and lower detachment exacerbated the positive association between both job demands and aggression and emotional exhaustion. The implications of the findings for the wellbeing and professional functioning of prison officers are discussed, together with key areas for future research

Topological susceptibility with the improved Asqtad action

As a test of the chiral properties of the improved Asqtad (staggered fermion) action, we have been measuring the topological susceptibility as a function of quark masses for 2 + 1 dynamical flavors. We report preliminary results, which show reasonable agreement with leading order chiral perturbation theory for lattice spacing less than 0.1 fm. The total topological charge, however, shows strong persistence over Monte Carlo time.Comment: Lattice2002(algor

Protocolised non-invasive compared with invasive weaning from mechanical ventilation for adults in intensive care : the Breathe RCT

Background: Invasive mechanical ventilation (IMV) is a life-saving intervention. Following resolution of the condition that necessitated IMV, a spontaneous breathing trial (SBT) is used to determine patient readiness for IMV discontinuation. In patients who fail one or more SBTs, there is uncertainty as to the optimum management strategy. Objective: To evaluate the clinical effectiveness and cost-effectiveness of using non-invasive ventilation (NIV) as an intermediate step in the protocolised weaning of patients from IMV. Design: Pragmatic, open-label, parallel-group randomised controlled trial, with cost-effectiveness analysis. Setting: A total of 51 critical care units across the UK. Participants: Adult intensive care patients who had received IMV for at least 48 hours, who were categorised as ready to wean from ventilation, and who failed a SBT. Interventions: Control group (invasive weaning): patients continued to receive IMV with daily SBTs. A weaning protocol was used to wean pressure support based on the patient’s condition. Intervention group (non-invasive weaning): patients were extubated to NIV. A weaning protocol was used to wean inspiratory positive airway pressure, based on the patient’s condition. Main outcome measures: The primary outcome measure was time to liberation from ventilation. Secondary outcome measures included mortality, duration of IMV, proportion of patients receiving antibiotics for a presumed respiratory infection and health-related quality of life. Results: A total of 364 patients (invasive weaning, n = 182; non-invasive weaning, n = 182) were randomised. Groups were well matched at baseline. There was no difference between the invasive weaning and non-invasive weaning groups in median time to liberation from ventilation {invasive weaning 108 hours [interquartile range (IQR) 57–351 hours] vs. non-invasive weaning 104.3 hours [IQR 34.5–297 hours]; hazard ratio 1.1, 95% confidence interval [CI] 0.89 to 1.39; p = 0.352}. There was also no difference in mortality between groups at any time point. Patients in the non-invasive weaning group had fewer IMV days [invasive weaning 4 days (IQR 2–11 days) vs. non-invasive weaning 1 day (IQR 0–7 days); adjusted mean difference –3.1 days, 95% CI –5.75 to –0.51 days]. In addition, fewer non-invasive weaning patients required antibiotics for a respiratory infection [odds ratio (OR) 0.60, 95% CI 0.41 to 1.00; p = 0.048]. A higher proportion of non-invasive weaning patients required reintubation than those in the invasive weaning group (OR 2.00, 95% CI 1.27 to 3.24). The within-trial economic evaluation showed that NIV was associated with a lower net cost and a higher net effect, and was dominant in health economic terms. The probability that NIV was cost-effective was estimated at 0.58 at a cost-effectiveness threshold of £20,000 per quality-adjusted life-year. Conclusions: A protocolised non-invasive weaning strategy did not reduce time to liberation from ventilation. However, patients who underwent non-invasive weaning had fewer days requiring IMV and required fewer antibiotics for respiratory infections. Future work: In patients who fail a SBT, which factors predict an adverse outcome (reintubation, tracheostomy, death) if extubated and weaned using NIV? Trial registration: Current Controlled Trials ISRCTN15635197. Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 48. See the NIHR Journals Library website for further project information

Social physique anxiety and physical activity in early adolescent girls : the influence of maturation and physical activity motives

This study considered the influence of maturation on social physique anxiety (SPA), the relationship between SPA and current and future physical activity (PA) levels and the influence of motives for physical activity on this relationship in early adolescent girls (n=162; mean age=11.80±0.33 years). Participants completed the Pubertal Development Scale, the modified Social Physique Anxiety Scale and the Motives for Physical Activity Scale at baseline and the Physical Activity Questionnaire for Older Children at baseline and 6 months later. The girls became less active across the 6 months and girls in the early stages of maturation had significantly lower SPA than the girls in the middle and late stages of maturation. SPA was not related to current or future physical activity in the sample as a whole. Cluster analysis identified four groups with different motive profiles and the High Appearance and Fitness group demonstrated a moderate negative relationship between SPA and PA at phase 1, whereas the other groups did not. These findings indicate that SPA may increase with maturation and the relationship between SPA and PA is dependent on reasons for being active. For girls who are motivated to be active primarily by body-related reasons SPA is likely to lead to lower levels of PA

Lessons from using iPads to understand young children's creativity

This paper explores how iPads can be used as part of a child-centred data collection approach to understanding young children’s creativity. Evidence is presented from a pilot study about 3- to 5-year-old children’s creative play. Researchers’ reflective accounts of children’s engagement with iPad video diaries and free to use apps were logged across two early educational settings over a three-month period. Findings suggest that iPads offer a mechanism to allow children to express their creative play and to encourage involvement in the research process. However, bespoke research software to use with early years children is required to improve this process

Argo array observation of ocean heat content changes induced by tropical cyclones in the north Pacific

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C12025, doi:10.1029/2011JC007165.In situ observations from the autonomous Argo float array are used to assess the basin-averaged ocean heat content change driven by tropical cyclones (TCs) in the North Pacific for 2000–2008. A new statistical approach based on pairs of profiles before and after each TC event is employed here to estimate the near-surface and subsurface heat content changes. Previous studies have suggested a dominant role for vertical mixing in the SST cooling response during TC passages. The Argo float observations show that, under strong TCs (greater than or equal to category 4), the subsurface warming expected from vertical mixing occurs with comparable magnitude to near-surface cooling. However, when weak TCs (less than or equal to category 3, which are about 86% of the total of TCs) were also considered, the subsurface warming was not detectable in the Argo data set, while near-surface cooling was still significant. Therefore, these results suggest that air-sea heat exchange and (upward) vertical advection likely play a somewhat greater role in the case of weak TCs. Additionally, Argo observations suggest that the restoring time scale of the near-surface heat content is greater than 30 days, which may be compared with the approximately 10 day time scale for the restoration of sea surface temperature. The mixed layer temperature and mixed layer depth evolutions also estimated from Argo data support the notion that only a thin surface layer is restored quickly to pre-TC conditions, while the rest of the cooled near-surface layer retained the TC-induced response for a good deal longer.Support from NSF (OCE-0847160) and partly from the Meteorological Research Institute/KMA is gratefully acknowledged.2012-06-1