5,563 research outputs found

    Digital Games in the Science Classroom: Leveraging Internal and External Scaffolds during Game Play

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    We have developed a disciplinarily integrated game (DIG) to support students in interpreting, translating, and manipulating across formal representations in the domain of Newtonian kinematics. In this study, we seek to understand what game play looks like in a classroom context with particular attention given to how students leverage internal and external scaffolds to progress through the game and deepen their conceptual knowledge. We investigate the following questions: (1) In what ways do students interact with the game, with each other, and with their teacher when they play SURGE Symbolic in a classroom environment? (2) How do game scaffolds, both within and outside of the game, support or impede student learning and game play? (3) What are the implications of these observations for teachers and game designers? We found that although most students used internal scaffolds in some way to assist their game play, many found that these scaffolds were insufficient to get through challenges. They quickly sought help from external resources available to them outside the game to help them advance in the game. The source of information they needed to make progress came from various people or resources outside the game, what we are calling “knowers.

    Invariant expectations and vanishing of bounded cohomology for exact groups

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    We study exactness of groups and establish a characterization of exact groups in terms of the existence of a continuous linear operator, called an invariant expectation, whose properties make it a weak counterpart of an invariant mean on a group. We apply this operator to show that exactness of a finitely generated group GG implies the vanishing of the bounded cohomology of GG with coefficients in a new class of modules, which are defined using the Hopf algebra structure of â„“1(G)\ell_1(G).Comment: Final version, to appear in the Journal of Topology and Analysi

    Using Common Gardens and AFLP Analyses to Identify Metapopulations of Indigenous Plant Materials for Rangeland Revegetation in Western USA

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    Past mismanagement, overgrazing, invasive weedy species, wildfires, marginal crop production, mineral and energy extraction, recreation and global climate change are challenges currently facing rangelands (Pierson et al. 2011). These disturbances may lead to long-term reductions in biodiversity, altered nutrient and water cycling, diminished forage production for livestock and wildlife, increased wildfire frequency and increased soil erosion and stream sedimentation (Sheley et al. 2008). Rangeland revegetation with desirable plant materials may be required to improve degraded conditions, speed recovery, and prevent further erosion and degradation. There is a critical need for plant materials to restore and revegetate rangeland ecosystems. Legumes indigenous to western North America are of particular interest for revegetation because they provide biologically fixed nitrogen, increase plant production, enhance forage quality and provide food sources for grazing animals and pollinators. Some land managers in the USA are concerned with the genetic identity of populations used for revegetation. To balance concerns of genetic identity, ecological adaptation, and economical seed production, we assessed genetic variation and its phenotypic expression in Astragalus filipes Torr. ex A. Gray (basalt milkvetch), Dalea ornata (Douglas) Eaton & Wright (western prairie clover) and D. searlsiae (A. Gray) Barneby (Searls’ prairie clover) using common-garden and AFLP (amplified fragment length polymorphism) techniques. These data were used to define population structures (genetically differentiated groups) within each species, which served as a basis for commercial release and rangeland revegetation (Johnson et al. 2012)

    Feminist Scholarship Review: Women and Music

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    Published from 1991 through 2007 at Trinity College, Hartford, Connecticut, the Feminist Scholarship Review is a literary journal that describes women\u27s experiences around the world. FSR began as a review of feminist scholarly material, but evolved into a journal for poetry and short storie

    Dedication

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    This issue of the Nebraska Law Review is dedicated to the Honorable Earl Warren, Chief Justice of the United States, upon his retirement

    Chronic traumatic encephalopathy is a common co-morbidity, but less frequent primary dementia in former soccer and rugby players

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    Chronic traumatic encephalopathy (CTE) is reported at high prevalence in selected autopsy case series of former contact sports athletes. Nevertheless, the contribution of CTE pathology to clinical presentation and its interaction with co-morbid neurodegenerative pathologies remain unclear. To address these issues, we performed comprehensive neuropathology assessments on the brains of former athletes with dementia and considered these findings together with detailed clinical histories to derive an integrated clinicopathological diagnosis for each case. Consecutive, autopsy-acquired brains from former soccer and rugby players with dementia were assessed for neurodegenerative pathologies using established and preliminary consensus protocols. Thereafter, next of kin interviews were conducted to obtain detailed accounts of the patient’s clinical presentation and course of disease to inform a final, integrated clinicopathological diagnosis. Neuropathologic change consistent with CTE (CTE-NC) was confirmed in five of seven former soccer and three of four former rugby players’ brains, invariably in combination with mixed, often multiple neurodegenerative pathologies. However, in just three cases was the integrated dementia diagnosis consistent with CTE, the remainder having alternate diagnoses, with the most frequent integrated diagnosis Alzheimer’s disease (AD) (four cases; one as mixed AD and vascular dementia). This consecutive autopsy series identifies neuropathologic change consistent with preliminary diagnostic criteria for CTE (CTE-NC) in a high proportion of former soccer and rugby players dying with dementia. However, in the majority, CTE-NC appears as a co-morbidity rather than the primary, dementia causing pathology. As such, we suggest that while CTE-NC might be common in former athletes with dementia, in many cases its clinical significance remains uncertain

    A New Suite of Plasmid Vectors for Fluorescence-Based Imaging of Root Colonizing Pseudomonads

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    In the terrestrial ecosystem, plant–microbe symbiotic associations are ecologically and economically important processes. To better understand these associations at structural and functional levels, different molecular and biochemical tools are applied. In this study, we have constructed a suite of vectors that incorporates several new elements into the rhizosphere stable, broad-host vector pME6031. The new vectors are useful for studies requiring multi-color tagging and visualization of plant-associated, Gram-negative bacterial strains such as Pseudomonas plant growth promotion and biocontrol strains. A number of genetic elements, including constitutive promoters and signal peptides that target secretion to the periplasm, have been evaluated. Several next generation fluorescent proteins, namely mTurquoise2, mNeonGreen, mRuby2, DsRed-Express2 and E2-Crimson have been incorporated into the vectors for whole cell labeling or protein tagging. Secretion of mTurquoise2 and mNeonGreen into the periplasm of Pseudomonas fluorescens SBW25 has also been demonstrated, providing a vehicle for tagging proteins in the periplasmic compartment. A higher copy number version of select plasmids has been produced by introduction of a previously described repA mutation, affording an increase in protein expression levels. The utility of these plasmids for fluorescence-based imaging is demonstrated by root colonization of Solanum lycopersicum seedlings by P. fluorescens SBW25 in a hydroponic growth system. The plasmids are stably maintained during root colonization in the absence of selective pressure for more than 2 weeks
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