Computational Essays in the Physics Classroom

Writing and argumentation are critical to both professional physics and physics education. However, the skill of making an extended argument in writing is often overlooked in physics classrooms, apart from certain practices like lab notebooks or mathematical proofs. Computation is also critical to both professional physics and, increasingly, physics education. In recent years we have begun to develop a class of assignment, known as a computational essay, to both leverage the creative affordances of computation and help students build their argumentative writing skills. Computational essays are a type of essay or report that combine text and code to express an idea or make an argument, usually written in notebook software. In this article, we describe the motivation and philosophy behind computational essays, as well as initial results from a pilot implementation in an introductory undergraduate electricity and magnetism course.Comment: Published in The Physics Teacher: https://aapt.scitation.org/doi/10.1119/1.514547

Understanding Student Computational Thinking with Computational Modeling

Recently, the National Research Council's framework for next generation science standards highlighted "computational thinking" as one of its "fundamental practices". 9th Grade students taking a physics course that employed the Modeling Instruction curriculum were taught to construct computational models of physical systems. Student computational thinking was assessed using a proctored programming assignment, written essay, and a series of think-aloud interviews, where the students produced and discussed a computational model of a baseball in motion via a high-level programming environment (VPython). Roughly a third of the students in the study were successful in completing the programming assignment. Student success on this assessment was tied to how students synthesized their knowledge of physics and computation. On the essay and interview assessments, students displayed unique views of the relationship between force and motion; those who spoke of this relationship in causal (rather than observational) terms tended to have more success in the programming exercise.Comment: preprint to submit to PERC proceedings 201

Comparison Of Heavy Metals In Aquatic Plants On Charity Island, Saginaw Bay, Lake Huron, U.S.A., With Plants Along The Shoreline Of Saginaw Bay

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141439/1/ajb208285.pd

Ancient papillomavirus-host co-speciation in Felidae

The evolutionary rate of feline papillomaviruses is inferred from the phylogenetic analysis of their hosts, providing evidence for long-term virus-host co-speciatio

Effect of multi-planar CT image reformatting on surgeon diagnostic performance for localizing thoracolumbar disc extrusions in dogs

Accurate pre-operative localization and removal of disc material are important for minimizing morbidity in dogs with thoracolumbar disc extrusions. Computed tomography (CT) is an established technique for localizing disc extrusions in dogs, however the effect of multi-planar reformatting (MPR) on surgeon diagnostic performance has not been previously described. The purpose of this study was to test the effect of MPR CT on surgeon diagnostic accuracy, certainty and agreement for localizing thoracolumbar disc extrusions in dogs. Two veterinary surgeons and one veterinary neurologist who were unaware of surgical findings independently reviewed randomized sets of two-dimensional (2D) and MPR CT images from 111 dogs with confirmed thoracolumbar disc extrusions. For each set of images, readers recorded their localizations for extruded disc material and their diagnostic certainty. For MPR images, readers also recorded views they considered most helpful. Diagnostic accuracy estimates, mean diagnostic certainty scores and inter-observer agreement were compared using surgery as the gold standard. Frequencies were compared for MPR views rated most helpful. Diagnostic accuracy estimates were significantly greater for MPR vs. 2D CT images in one reader. Mean diagnostic certainty scores were significantly greater for MPR images in two readers. The change in agreement between 2D and MPR images differed from zero for all analyses (site, side, number affected) among all three readers. Multi-planar views rated most helpful with the highest frequency were oblique transverse and curved dorsal planar MPR views. Findings from this study indicate that multi-planar CT can improve surgeon diagnostic performance for localizing canine thoracolumbar disc extrusions

Determinants of selenium status in healthy adults

<p>Abstract</p> <p>Background</p> <p>Selenium (Se) status in non-deficient subjects is typically assessed by the Se contents of plasma/serum. That pool comprises two functional, specific selenoprotein components and at least one non-functional, non-specific components which respond differently to changes in Se intake. A more informative means of characterizing Se status in non-deficient individuals is needed.</p> <p>Methods</p> <p>Multiple biomarkers of Se status (plasma Se, serum selenoprotein P [SEPP1], plasma glutathione peroxidase activity [GPX3], buccal cell Se, urinary Se) were evaluated in relation to selenoprotein genotypes (GPX1, GPX3, SEPP1, SEP15), dietary Se intake, and parameters of single-carbon metabolism in a cohort of healthy, non-Se-deficient men (n = 106) and women (n = 155).</p> <p>Conclusions</p> <p>Plasma Se concentration was 142.0 ± 23.5 ng/ml, with GPX3 and serum-derived SEPP1 calculated to comprise 20% and 34%, respectively, of that total. The balance, comprised of non-specific components, accounted for virtually all of the interindividual variation in total plasma Se. Buccal cell Se was associated with age and plasma homocysteine (hCys), but not plasma Se. SEPP1 showed a quadratic relationship with body mass index, peaking at BMI 25-30. Urinary Se was greater in women than men, and was associated with metabolic body weight (kg^0.75), plasma folate, vitamin B₁₂and hCys (negatively). One <it>GPX1 </it>genotype (679T/T) was associated with significantly lower plasma Se levels than other allelic variants. Selenium intake, estimated from food frequency questionnaires, did not predict Se status as indicated by any biomarker. These results show that genotype, methyl-group status and BMI contribute to variation in Se biomarkers in Se-adequate individuals.</p

Forest and woodland replacement patterns following drought-related mortality

Forest vulnerability to drought is expected to increase under anthropogenic climate change, and drought-induced mortality and community dynamics following drought have major ecological and societal impacts. Here, we show that tree mortality concomitant with drought has led to short-term (mean 5 y, range 1 to 23 y after mortality) vegetation-type conversion in multiple biomes across the world (131 sites). Self-replacement of the dominant tree species was only prevalent in 21% of the examined cases and forests and woodlands shifted to nonwoody vegetation in 10% of them. The ultimate temporal persistence of such changes remains unknown but, given the key role of biological legacies in long-term ecological succession, this emerging picture of postdrought ecological trajectories highlights the potential for major ecosystem reorganization in the coming decades. Community changes were less pronounced under wetter postmortality conditions. Replacement was also influenced by management intensity, and postdrought shrub dominance was higher when pathogens acted as codrivers of tree mortality. Early change in community composition indicates that forests dominated by mesic species generally shifted toward more xeric communities, with replacing tree and shrub species exhibiting drier bioclimatic optima and distribution ranges. However, shifts toward more mesic communities also occurred and multiple pathways of forest replacement were observed for some species. Drought characteristics, species-specific environmental preferences, plant traits, and ecosystem legacies govern post drought species turnover and subsequent ecological trajectories, with potential far-reaching implications for forest biodiversity and ecosystem services.Peer reviewe

Phase II evaluation of MGBG in non-small cell carcinoma of the lung

One hundred and eight patients with non-small cell lung cancer were treated in a Phase II trial with MGBG at a dose of 600 mg/m 2 i.v. weekly. Partial responses were noted in 3/43 patients with adenocarcinoma and 1/40 with squamous cell carcinoma. No responses were noted in 24 patients with large cell carcinoma. Overall, the drug was reasonably well-tolerated. At this dosage and schedule, MGBG has no substantial antitumor activity for patients with non-small cell lung cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45128/1/10637_2004_Article_BF00180196.pd

Using Parahydrogen Induced Polarization to Study Steps in the Hydroformylation Reaction.

A range of iridium complexes, Ir(η3-C3H5)(CO)(PR2R’)2 (1a-1e) [where 1a, PR2R’ = PPh3, 1b P(p-tol)3, 1c PMePh2, 1d PMe2Ph and 1e PMe3] were synthesized and their reactivity as stoichiometric hydroformylation precursors studied. Para-hydrogen assisted NMR spectroscopy detected the following intermediates: Ir(H)2(η3-C3H5)(CO)(PR2R’) (2a-e), Ir(H)2(η1-C3H5)(CO)(PR2R’)2 (4d-e), Ir(H)2(η1-C3H5)(CO)2(PR2R’) (10a-e), Ir(H)2(CO-C3H5)(CO)2(PR2R’) (11a-c), Ir(H)2(CO-C3H7)(CO)2(PR2R’) (12a-c) and Ir(H)2(CO-C3H5)(CO)(PR2R’)2 (13d-e). Some of these species exist as two geometric isomers according to their multinuclear NMR characteristics. The NMR studies suggest a role for the following 16 electron species in these reactions: Ir(η3-C3H5)(CO)(PR2R’), Ir(η1-C3H5)(CO)(PR2R’)2, Ir(η1-C3H5)(CO)2(PR2R’), Ir(CO-C3H5)(CO)2(PR2R’), Ir(CO-C3H7)(CO)2(PR2R’) and Ir(CO-C3H5)(CO)(PR2R’)2. Their role is linked to several 18 electron species in order to confirm the route by which hydroformylation and hydrogenation proceeds