Applications of Monte Carlo analysis to tungsten resonance absorption

Applications of Monte Carlo analysis to tungsten resonance absorptio

Extension of Case's method to the two-region critical cylinder and its application as an analytic standard

The normal mode expansion technique is applied to the transformed monoenergetic integral transport equation to develop a solution for the rotationally invariant and axially infinite, critical, two-region cylinder with a finite outer reflector boundary. Isotropic scattering and identical neutron mean free paths in the core and reflector regions are assumed. The solution in terms of singular integral equations is obtained by applying a completeness theorem found for the singular eigenfunctions. Numerical results for a variety of core and reflector multiplying properties and reflector thickness are presented and compared with the results of other method. An example of this type of application is given in a study of approximations inherent in the neutronic design analysis of a small, fast-neutron-spectrum reactor concept proposed as a space power source

How soon should serum potassium levels be monitored for patients started on diuretics?

Case series show that hypokalemia following initiation of diuretic therapy occurs in most patients within 2 to 8 weeks. However, no studies are available that adequately predict the risk of this complex and multifactorial condition. Patients taking diuretics should have a potassium level checked in the first 2 to 8 weeks after initiating therapy. Mild hypokalemia (3.1 to 3.4 mmol/L) may be transient, so a repeat measurement may be considered before initiating potassium replacement. Dietary sodium restriction may also help to conserve potassium, because this will decrease urinary flow rate and potassium loss. The frequency with which to check potassium levels should be guided by the patients' underlying clinical conditions and dietary potassium and sodium intake. (Grade of Recommendation: C, based on case series

Small high-temperature nuclear reactors for space power

Criticality calculations for small, cylindrical, lithium cooled reactors for space power system

Recombination Ghosts in Littrow Configuration: Implications for Spectrographs Using Volume Phase Holographic Gratings

We report the discovery of optical ghosts generated when using Volume Phase Holographic (VPH) gratings in spectrographs employing the Littrow configuration. The ghost is caused by light reflected off the detector surface, recollimated by the camera, recombined by, and reflected from, the grating and reimaged by the camera onto the detector. This recombination can occur in two different ways. We observe this ghost in two spectrographs being developed by the University of Wisconsin - Madison: the Robert Stobie Spectrograph for the Southern African Large Telescope and the Bench Spectrograph for the WIYN 3.5m telescope. The typical ratio of the brightness of the ghost relative to the integrated flux of the spectrum is of order 10^-4, implying a recombination efficiency of the VPH gratings of order 10^-3 or higher, consistent with the output of rigorous coupled wave analysis. Any spectrograph employing VPH gratings, including grisms, in Littrow configuration will suffer from this ghost, though the general effect is not intrinsic to VPH gratings themselves and has been observed in systems with conventional gratings in non-Littrow configurations. We explain the geometric configurations that can result in the ghost as well as a more general prescription for predicting its position and brightness on the detector. We make recommendations for mitigating the ghost effects for spectrographs and gratings currently built. We further suggest design modifications for future VPH gratings to eliminate the problem entirely, including tilted fringes and/or prismatic substrates. We discuss the resultant implications on the spectrograph performance metrics.Comment: 13 pages, 8 figures, emulateapj style, accepted for publication in PAS

The Association Between the Coach-Athlete Relationship and Burnout Among High School Coaches

Burnout is a term that continues to raise considerable concern among high school coaches and administrators (Raedeke, 1997) and has shown to have negative effects on coaches and athletes alike (Price & Weiss, 2000; Vealey, Armstrong, & Comar, 1998). While burnout has shown to have significant adverse effects, few studies have examined how the coach-athlete relationship may affect a coach s level of perceived burnout. This study sought to understand if the coach-athlete relationship predicted coach burnout. High school coaches (69 males, 62 females) completed the Coach-Athlete Relationship Questionnaire (CART-Q; Jowett & Ntoumanis, 2004), the Coaching Burnout Questionnaire, a modified version of the Athlete Burnout Questionnaire (ABO; Raedeke & Smith. 2001), as well as demographic and background assessments. Results of a multivariate multiple regression indicated that coaches who perceived themselves as committed and had complementary goals with their athletes, showed significantly lower levels o f burnout on all three dimensions. Results indicate that coaches should strive to ensure that they have goals that align with their athletes ’goals and develop a sustained and committed relationship with their players

Projected Deaths of Despair from COVID-19

More Americans could lose their lives to deaths of despair, deaths due to drug, alcohol, and suicide, if we do not do something immediately. Deaths of despair have been on the rise for the last decade, and in the context of COVID-19, deaths of despair should be seen as the epidemic within the pandemic. The goal of this report is to predict what deaths of despair we might see based on three assumptions during COVID-19: economic recovery, relationship between deaths of despair and unemployment, and geography. Across nine different scenarios, additional deaths of despair range from 27,644 (quick recovery, smallest impact of unemployment on deaths of despair) to 154,037 (slow recovery, greatest impact of unemployment on deaths of despair), with somewhere in the middle being around 68,000. However, these data are predictions. We can prevent these deaths by taking meaningful and comprehensive action as a nation

How can I improve patient adherence to prescribed medication?

Two randomized clinical trials have shown that simplified dosing schedules have improved patient adherence to medication as prescribed. Some, but not all, randomized controlled trials show multidimensional interventions can also improve adherence. These interventions include combinations of patient and family education, home monitoring of disease status, and increased convenience of care, such as workplace access. (Grade of Recommendation: B, based on randomized controlled trials