Normalized power priors always discount historical data

Power priors are used for incorporating historical data in Bayesian analyses by taking the likelihood of the historical data raised to the power α as the prior distribution for the model parameters. The power parameter α is typically unknown and assigned a prior distribution, most commonly a beta distribution. Here, we give a novel theoretical result on the resulting marginal posterior distribution of α in case of the normal and binomial model. Counterintuitively, when the current data perfectly mirror the historical data and the sample sizes from both data sets become arbitrarily large, the marginal posterior of α does not converge to a point mass at α=1 but approaches a distribution that hardly differs from the prior. The result implies that a complete pooling of historical and current data is impossible if a power prior with beta prior for α is used

Assessing and monitoring student progress in e-learning environments

E-learning has emerged as a form of pedagogy and as a delivery system with broad implications for meeting personnel needs nationally in special education. At present, it is important to make investments in research and development to ensure that this new pedagogy becomes fully developed and is appropriately applied. Assessment and monitoring of student progress in e-learning environments is an important element of this new form of pedagogy that requires research attention to maximize the effectiveness of e-learning when applied to teacher education. The authors draw upon their personal online teaching experience in addressing strategies for assessing student performance and using electronic portfolios in e-learning environments, both presented as integral aspects of e-learning instructional process. Perspectives from the literature and lessons learned from the authors’ own experience are shared.peerreviewe

The magnetic interactions in spin-glasslike Ge/1-x-y/Sn/x/Mn/y/Te diluted magnetic semiconductor

We investigated the nature of the magnetic phase transition in the Ge/1-x-y/Sn/x/Mn/y/Te mixed crystals with chemical composition changing in the range of 0.083 < x < 0.142 and 0.012 < y < 0.119. The DC magnetization measurements performed in the magnetic field up to 90 kOe and temperature range 2-200 K showed that the magnetic ordering at temperatures below T = 50 K exhibits features characteristic for both spin-glass and ferromagnetic phases. The modified Sherrington - Southern model was applied to explain the observed transition temperatures. The calculations showed that the spin-glass state is preferred in the range of the experimental carrier concentrations and Mn content. The value of the Mn hole exchange integral was estimated to be J/pd/ = 0.45+/-0.05 eV. The experimental magnetization vs temperature curves were reproduced satisfactory using the non-interacting spin-wave theory with the exchange constant J/pd/ values consistent with those calculated using modified Sherrington - Southern model. The magnetization vs magnetic field curves showed nonsaturating behavior at magnetic fields B < 90 kOe indicating the presence of strong magnetic frustration in the system. The experimental results were reproduced theoretically with good accuracy using the molecular field approximation-based model of a disordered ferromagnet with long-range RKKY interaction.Comment: 9 pages, 6 figure

Participatory organizational intervention for improved use of assistive devices for patient transfer:study protocol for a single-blinded cluster randomized controlled trial

BACKGROUND: Epidemiological studies have shown that patient transfer is a risk factor for back pain, back injuries and long term sickness absence, whereas consistent use of assistive devices during patient transfer seems to be protective. While classical ergonomic interventions based on education and training in lifting and transferring techniques have not proven to be effective in preventing back pain, participatory ergonomics, that is meant to engage and motivate the involved parties while at the same time making the intervention maximally relevant, may represent a better solution. However, these findings are largely based on uncontrolled studies and thus lack to be confirmed by studies with better study designs. In this article, we present the design of a study which aims to evaluate the effect and process of a participatory organizational intervention for improved use of assistive devices. METHODS: The study was performed as a cluster randomized controlled trial. We recruited 27 departments (clusters) from five hospitals in Denmark to participate in the study. Prior to randomization, interviews, observations and questionnaire answers (baseline questionnaire) were collected to gain knowledge of barriers and potential solutions for better use of assistive devices. In April 2016, the 27 departments were randomly allocated using a random numbers table to a participatory intervention (14 clusters, 324 healthcare workers) or a control group (13 clusters, 318 healthcare workers). The participatory intervention will consist of workshops with leaders and selected healthcare workers of each department. Workshop participants will be asked to discuss the identified barriers, develop solutions for increasing the use of assistive devices and implement them in their department. Use of assistive devices (using digital counters -, primary outcome, and accelerometers and questionnaire - secondary outcome), perceived physical exertion during patient transfer, pain intensity in the lower back, occurrence of work-related back injuries during patient transfer, organizational readiness to change, knowledge on how to perform proper patient transfer, social capital and work ability (secondary outcomes) were assessed at baseline and will also be assessed at 1 year follow-up. Process evaluation will be based on qualitative and quantitative data to assess the implementation, the change process, and the impact of context aspects. DISCUSSION: The study will evaluate the effect and process of a participatory intervention on improving the use of assistive devices for patient transfer among hospital healthcare workers. By using cluster-randomization, as well as process- and effect evaluation based on objective measures we will contribute to the evidence base of a promising intervention approach. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02708550). March, 2016

Monarch Butterfly (Danaus Plexippus) Life-Stage Risks from Foliar and Seed-Treatment Insecticides

Conservation of North America\u27s eastern monarch butterfly (Danaus plexippus) population would require establishment of milkweed (Asclepias spp.) and nectar plants in the agricultural landscapes of the north central United States. A variety of seed-treatment and foliar insecticides are used to manage early- and late-season pests in these landscapes. Thus, there is a need to assess risks of these insecticides to monarch butterfly life stages to inform habitat conservation practices. Chronic and acute dietary toxicity studies were undertaken with larvae and adults, and acute topical bioassays were conducted with eggs, pupae, and adults using 6 representative insecticides: beta-cyfluthrin (pyrethroid), chlorantraniliprole (anthranilic diamide), chlorpyrifos (organophosphate), imidacloprid, clothianidin, and thiamethoxam (neonicotinoids). Chronic dietary median lethal concentration values for monarch larvae ranged from 1.6 x 10-3 (chlorantraniliprole) to 5.3 (chlorpyrifos) μg/g milkweed leaf, with the neonicotinoids producing high rates of arrested pupal ecdysis. Chlorantraniliprole and beta-cyfluthrin were generally the most toxic insecticides to all life stages, and thiamethoxam and chlorpyrifos were generally the least toxic. The toxicity results were compared to insecticide exposure estimates derived from a spray drift model and/or milkweed residue data reported in the literature. Aerial applications of foliar insecticides are expected to cause high downwind mortality in larvae and eggs, with lower mortality predicted for adults and pupae. Neonicotinoid seed treatments are expected to cause little to no downslope mortality and/or sublethal effects in larvae and adults. Given the vagile behavior of nonmigratory monarchs, considering these results within a landscape-scale context suggests that adult recruitment will not be negatively impacted if new habitat is established in close proximity of maize and soybean fields in the agricultural landscapes of the north central United States

Adelaide in-depth accident study 1975-1979. Part 5: Commercial vehicle accidents

This report deals with accidents involving trucks, vans, buses and multi-purpose vehicles, not all of which were being used as commercial vehicles. There were relatively few single vehicle accidents, apart from those involving pedestrians, and the reluctance of semitrailer drivers to brake hard at s~gnalisedin tersections and insecure loads of some heavy vehicles distinguished these accidents from those involving only passenger cars. All but one of the drivers of these commercial vehicles were males, most of whom were aged between 20 and 50 years. None of these drivers were affected by alcohol intoxication to a significant degree, nor was fatigue a factor in any of these accidents. Although none of the commercial vehicle occupants was severely injured, the provision and use of seat belts may have avoided many of the injuries which did occur. Some multi-purpose passenger vehicles are deficient, when compared to passenger cars, in terms of protecting their occupants from injury in a crash.A.J. Mclean, H.S. Aust, B.L. Sando

Czech Social Reform/Non-reform: Routes, Actors and Problems

In this contribution, the author first considers the characteristics of the Czechoslovak communist welfare state and its theoretical alternatives. Throughout the reform process, dependency on both corporatist and socialist regimes won out, while residualist efforts were promoted in the beginning, but were later held back. The author then considers the possible actors involved in social reforms. In this respect, when proceeding from a general to a more concrete level, thought should first be devoted to the social classes and their ideologies, and second to political parties and their leaders. The author goes on to summarise the particular problems and traps in individual sections of the Czech social system. While no objection to decent standards of social protection and health care could be raised, the poor efficiency of their achievement should evoke concern. The author concludes by reflecting on the possible specificities of Czech social reform in comparison with the other countries undergoing reform and the EU. The current lethargy of the Czech welfare system corresponds to a “frozen edifice”, just as in most Western countries. However, such stagnation is apparently acceptable to both the politicians (who mask it in reformist rhetoric) and the population (which learned to master taking advantage of the generous welfare state) and thus is basically sustainable in the long run.http://deepblue.lib.umich.edu/bitstream/2027.42/40037/3/wp651.pd

Understanding the nature of "superhard graphite"

Numerous experiments showed that on cold compression graphite transforms into a new superhard and transparent allotrope. Several structures with different topologies have been proposed for this phase. While experimental data are consistent with these models, the only way to solve this puzzle is to find which structure is kinetically easiest to form. Using state-of-the-art molecular-dynamics transition path sampling simulations, we investigate kinetic pathways of the pressure-induced transformation of graphite to various superhard candidate structures. Unlike hitherto applied methods for elucidating nature of superhard graphite, transition path sampling realistically models nucleation events necessary for physically meaningful transformation kinetics. We demonstrate that nucleation mechanism and kinetics lead to $M$-carbon as the final product. $W$-carbon, initially competitor to $M$-carbon, is ruled out by phase growth. Bct-C$_4$ structure is not expected to be produced by cold compression due to less probable nucleation and higher barrier of formation