Super-Eddington Atmospheres that Don't Blow Away

We show that magnetized, radiation dominated atmospheres can support steady state patterns of density inhomogeneity that enable them to radiate at far above the Eddington limit, without suffering mass loss. The inhomogeneities consist of periodic shock fronts bounding narrow, high-density regions, interspersed with much broader regions of low density. The radiation flux avoids the regions of high density, which are therefore weighed down by gravity, while gas in the low-density regions is slammed upward into the shock fronts by radiation force. As the wave pattern moves through the atmosphere, each parcel of matter alternately experiences upward and downward forces, which balance on average. Magnetic tension shares the competing forces between regions of different densities, preventing the atmosphere from blowing apart. We calculate the density structure and phase speed of the wave pattern, and relate these to the wavelength, the density contrast, and the factor by which the net radiation flux exceeds the Eddington limit. In principle, this factor can be as large as the ratio of magnetic pressure to mean gas pressure, or the ratio of radiation pressure to gas pressure, whichever is smaller. Although the magnetic pressure must be large compared to the mean gas pressure in order to support a large density contrast, it need not be large compared to the radiation pressure. These highly inhomogeneous flows could represent the nonlinear development of the "photon bubble" instability discovered by Gammie. We briefly discuss the applicability of these solutions to astrophysical systems.Comment: 11 pages, 1 figure, accepted for publication in The Astrophysical Journa

Risk-based bridge scour management:a survey

Scour is one of the major causes of bridge failure worldwide and results in significant economic losses through disruption to operation. This phenomenon naturally affects bridges with underwater foundations and is exacerbated during high river and/or turbulent flows (e.g. due to extreme events). When scour reaches the bottom or undermines shallow foundations it is likely to trigger various damage mechanisms that may in-fluence the safety of the structure and force asset managers to reduce traffic capacity. Currently, assessing risk of scour is a heuristic process, heavily reliant on qualitative approaches and expert opinion (e.g. visual inspections). These types of assessments typically suffer from insufficient knowledge of influencing factors (e.g. hydraulic parameters) and the requirement to rely on several assumptions (e.g. foundation depth). As a result, current scour assessment and bridge management practices do not provide reliable solutions for ad-dressing the potential risk of bridge failures. In this paper, cross-cutting needs and challenges related to the development of decision support tools for scour-risk management are highlighted and some preliminary re-sults of a literature survey are reported. The review has been performed with several objectives: (i) identify-ing scour-risk indicators describing hydrodynamic actions and the asset condition; (ii) defining indirect and direct consequences needed to assess the risks associated to different decision alternatives related to scour management; and (iii) identifying existing approaches to scour inspections and monitoring as support tools for informed decisions. The results of this survey will serve as a base for future research aimed to develop an informed decision support tool to manage scour risk at both the bridge and at the network level

Differential effectiveness of residential versus outpatient aftercare for parolees from prison-based therapeutic community treatment programs

<p>Abstract</p> <p>Background</p> <p>Research has indicated that more intense treatment is associated with better outcomes among clients who are appropriately matched to treatment intensity level based on the severity of their drug/alcohol problem. This study examined the differential effectiveness of community-based residential and outpatient treatment attended by male and female drug-involved parolees from prison-based therapeutic community substance abuse treatment programs based on the severity of their drug/alcohol problem.</p> <p>Methods</p> <p>Subjects were 4,165 male and female parolees who received prison-based therapeutic community substance abuse treatment and who subsequently participated in <it>only </it>outpatient or <it>only </it>residential treatment following release from prison. The dependent variable of interest was return to prison within 12 months. The primary independent variables of interest were alcohol/drug problem severity (low, high) and type of aftercare (residential, outpatient). Chi-square analyses were conducted to examine the differences in 12-month RTP rates between and within the two groups of parolees (residential and outpatient parolees) based on alcohol/drug problem severity (low severity, high severity). Logistic regression analyses were performed to determine if aftercare modality (outpatient only vs. residential only) was a significant predictor of 12-month RTP rates for subjects who were classified as low severity versus those who were classified as high severity.</p> <p>Results</p> <p>Subjects benefited equally from outpatient and residential aftercare, regardless of the severity of their drug/alcohol problem.</p> <p>Conclusion</p> <p>As states and the federal prison system further expand prison-based treatment services, the demand and supply of aftercare treatment services will also increase. As this occurs, systems and policies governing the transitioning of individuals from prison- to community-based treatment should include a systematic and validated assessment of post-prison treatment needs and a valid and reliable means to assess the quality of community-based treatment services. They should also ensure that parolees experience a truly uninterrupted continuum of care through appropriate recognition of progress made in prison-based treatment.</p

Why are we seeing an increasing incidence of infective endocarditis in the UK?

The increasing incidence of infective endocarditis in England is real, and education is critical to ensure swift diagnosis and best clinical outcomes. Factors responsible remain speculative, but multiple explanations are likely

Nurses\u27 Alumnae Association Bulletin - Volume 5 Number 8

Calling All Nurses Financial Report Calendar of Events Lest You Forget! Attention Review of the Alumnae Association Meetings President\u27s Report Barton Memorial Division Oxygen Therapy Welcome, White Haven Alumnae Clinical Use of Penicillin in Infections of the Ears, Nose and Throat Address - Graduation of Nurses, 1945 Miscellaneous Items The Blood that Kills The Story of Malaria Program Prizes - May, 1946 Capping Exercises The Economic Security Program of the Pennsylvania State Nurses\u27 Association The Clara Melville Scholarship Fund Card of Thanks The Poet\u27s Corner The Hospital Pharmacy Jefferson Medical College Hospital School of Nursing Faculty Jefferson Hospital Gray Lady Unite, A.R.R. The Volunteer Nurses\u27 Aides Salute Jefferson Nurses Changes in the Staff at Jefferson Hospital Red Cross Recruits Did You Know That The Pennsylvania Nurse Medical College News Magazine and Newspaper Items Central Dressing Room and Transfusion Unit Rules Concerning Central Dressing Room Radios and Electrical Appliances Attending College Nurses in Anesthesia Condolences Marriages New Arrivals Deaths The Bulletin Committee Attention, Alumnae New Addresse

Challenging Perceptions of Disability through Performance Poetry Methods: The "Seen but Seldom Heard" Project.

This paper considers performance poetry as a method to explore lived experiences of disability. We discuss how poetic inquiry used within a participatory arts-based research framework can enable young people to collectively question society’s attitudes and actions towards disability. Poetry will be considered as a means to develop a more accessible and effective arena in which young people with direct experience of disability can be empowered to develop new skills that enable them to tell their own stories. Discussion of how this can challenge audiences to critically reflect upon their own perceptions of disability will also be developed

Optimization of inhomogeneous electron correlation factors in periodic solids

A method is presented for the optimization of one-body and inhomogeneous two-body terms in correlated electronic wave functions of Jastrow-Slater type. The most general form of inhomogeneous correlation term which is compatible with crystal symmetry is used and the energy is minimized with respect to all parameters using a rapidly convergent iterative approach, based on Monte Carlo sampling of the energy and fitting energy fluctuations. The energy minimization is performed exactly within statistical sampling error for the energy derivatives and the resulting one- and two-body terms of the wave function are found to be well-determined. The largest calculations performed require the optimization of over 3000 parameters. The inhomogeneous two-electron correlation terms are calculated for diamond and rhombohedral graphite. The optimal terms in diamond are found to be approximately homogeneous and isotropic over all ranges of electron separation, but exhibit some inhomogeneity at short- and intermediate-range, whereas those in graphite are found to be homogeneous at short-range, but inhomogeneous and anisotropic at intermediate- and long-range electron separation.Comment: 23 pages, 15 figures, 1 table, REVTeX4, submitted to PR

Field Deployment of an Ambient Vibration-Based Scour Monitoring System at Baildon Bridge, UK

Scour, the loss of material around bridge foundations due to hydraulic action, is the main cause of bridge failures in the United Kingdom and in many other parts of the world. Various techniques have been used to monitor bridge scour, ranging from scuba divers using crude depth measuring instrumentation to high-tech sonar and radar-based systems. In contrast to most other techniques, vibration-based scour monitoring uses accelerometers to provide real-time monitoring whilst also being robust and relatively simple to install. This is an indirect technique that aims to measure changes in the dynamic response of the structure due to the effects of scour, rather than attempting to measure scour directly. To date, research on vibration-based scour monitoring has been limited to laboratory-based experiments and numerical simulations, both of which have indicated that the natural frequencies of bridges should indeed be sensitive to scour. Due to pre-existing scouring, and planned repair work, Baildon Bridge in Shipley, Yorkshire provided a rare opportunity to validate vibration-based scour monitoring in both a scoured and a repaired state. A sensor system was deployed with 10 Epson low-noise, high-sensitivity accelerometers to measure the ambient vibration of the bridge before, during, and after the repair. This paper describes the installation of the accelerometer-based system, the numerical modelling of the bridge and the model updating carried out with the initial findings. Initial operational modal analysis has found two consistent vibration modes of the bridge that were scour sensitive according to the updated numerical model. But the variability of the measured frequencies, compared to the expected scour induced change in frequency, indicates a potential challenge for monitoring scour of small span bridges with vibration-based methods