No abstract

Physics education researchers (PER) commonly use complete-case analysis to address missing data. For complete-case analysis, researchers discard all data from any student who is missing any data. Despite its frequent use, no PER article we reviewed that used complete-case analysis provided evidence that the data met the assumption of missing completely at random (MCAR) necessary to ensure accurate results. Not meeting this assumption raises the possibility that prior studies have reported biased results with inflated gains that may obscure differences across courses. To test this possibility, we compared the accuracy of complete-case analysis and multiple imputation (MI) using simulated data. We simulated the data based on prior studies such that students who earned higher grades participated at higher rates, which made the data missing at random (MAR). PER studies seldom use MI, but MI uses all available data, has less stringent assumptions, and is more accurate and more statistically powerful than complete-case analysis. Results indicated that complete-case analysis introduced more bias than MI and this bias was large enough to obscure differences between student populations or between courses. We recommend that the PER community adopt the use of MI for handling missing data to improve the accuracy in research studies.

No abstract

is known for producing large volumes of iron-oxyhydroxide sheaths that alter wetland biogeochemistry. For over a century, these delicate structures have fascinated microbiologists and geoscientists. Because still resists long-term culture, the debate regarding its metabolic classification dates back to 1885. We developed a novel culturing technique for using natural waters, and coupled this with single cell genomics and nanoscale secondary ion mass spectrophotometry (nanoSIMS) to probe L. ochracea's physiology. In micro-slide cultures doubled every 5.7 hrs, had an absolute growth requirement for ferrous iron, had the genomic capacity for iron-oxidation, and a branched electron transport chain with cytochromes putatively involved in lithotrophic iron-oxidation. Additionally, its genome encoded several electron transport chain proteins including, a molybdopterin ACIII complex, a cytochrome oxidase reductase, and several terminal oxidase genes. contained two key autotrophic proteins in the Calvin Benson Bassham cycle, a Form II ribulose-bis-phosphate carboxylase and a phosphoribulose kinase. also assimilated bicarbonate, although calculations suggest bicarbonate assimilation is a small fraction of its total carbon assimilation. Finally, fundamental physiology is a hybrid of the chemolithotrophictype iron-oxidizing bacteria and the sheathed, heterotrophic filamentous metal-oxidizing bacteria of the genera. This allows to inhabit a unique niche within the neutrophilic iron seeps. was one of three groups of organisms Sergei Winogradsky used in the 1880s to develop the hypothesis on chemolithotrophy. continues to resist cultivation and appears to have an absolute requirement for organic rich waters suggesting its true physiology remains unknown. Further, is an ecological engineer, a few cells can generate prodigious volumes of iron-oxyhydroxides changing the ecosystem geochemistry and ecology. Therefore, to determine's basic physiology, we employed new single-cell techniques to demonstrate: oxidizes iron to generate energy and, despite predicted genes for autotrophic growth, assimilates a fraction of the total CO that autotrophs do. Although not a true chemolithoautotroph, 's physiological strategy allows it to be flexible, extensively colonize iron-rich wetlands.

With a minimal investment of resources, school nurses can become important sources of SRH information and condoms for male high school students.

No abstract

Background: Basic life support (BLS) skills decline rapidly without frequent practice. Deliberate practice (DP) and simulation scenarios have been shown to increase BLS skill retention for nursing students. In addition, BLS implementation in the hospital setting requires effective team skills, which are infrequently addressed in resuscitation courses or in nursing students' practice. An exploratory study to determine the impact of recurrent simulations with DP on BLS team skills was designed for senior nursing students. Method: Seven teams of students were followed over the course of one semester examining the impact of DP in recurrent simulation codes on BLS team skills. Results: Students attained effective BLS team performance after three hours of DP and sustained these skills over the semester with recurrent code practice. Conclusion: Recurring code team DP sustains BLS skills and is recommended for nursing students.

No abstract