894 research outputs found

    Nonverbal interaction between adults and young children during digital and real object play

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    This study explored the developmental play behaviors and use of nonverbal communication of children that are raised in homes that differ in the amount and kind of digital exposure they have experienced within the first three years of life. Thirty minute videotaped play sessions of seven different children ranging in age from 20 to 30 months who were categorized as having low digital exposure in the home, TV exposure only, or high digital exposure based on a digital use questionnaire completed by parents were coded for the contribution of eye gaze, body positioning, and hand movement engagement to negotiate play with real and digital objects. Average instances of eye gaze and body positioning were higher in the physical toy condition than in the digital toy condition, regardless of the children’s exposure to digital technology in the home. Average hand movement engagement for children in the low digital exposure group was higher when playing in the digital toy condition compared to the physical toy condition. It was essentially uniform in the physical toy condition and in the digital toy condition for the children in the TV exposure only and the high digital exposure groups. Results suggest that during play with digital toys, the amount of eye gaze and changes in body positioning displayed by the children were significantly decreased compared to physical toy play, regardless of the extent of digital exposure in the home. The average use of hand movement engagements, however, was acutely similar for physical and digital toy play conditions across all children

    Tendency of spherically imploding plasma liners formed by merging plasma jets to evolve toward spherical symmetry

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    Three dimensional hydrodynamic simulations have been performed using smoothed particle hydrodynamics (SPH) in order to study the effects of discrete jets on the processes of plasma liner formation, implosion on vacuum, and expansion. The pressure history of the inner portion of the liner was qualitatively and quantitatively similar from peak compression through the complete stagnation of the liner among simulation results from two one dimensional radiationhydrodynamic codes, 3D SPH with a uniform liner, and 3D SPH with 30 discrete plasma jets. Two dimensional slices of the pressure show that the discrete jet SPH case evolves towards a profile that is almost indistinguishable from the SPH case with a uniform liner, showing that non-uniformities due to discrete jets are smeared out by late stages of the implosion. Liner formation and implosion on vacuum was also shown to be robust to Rayleigh-Taylor instability growth. Interparticle mixing for a liner imploding on vacuum was investigated. The mixing rate was very small until after peak compression for the 30 jet simulation.Comment: 28 pages, 16 figures, submitted to Physics of Plasmas (2012

    Cohomology of finite dimensional pointed Hopf algebras

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    We prove finite generation of the cohomology ring of any finite dimensional pointed Hopf algebra, having abelian group of grouplike elements, under some mild restrictions on the group order. The proof uses the recent classification by Andruskiewitsch and Schneider of such Hopf algebras. Examples include all of Lusztig's small quantum groups, whose cohomology was first computed explicitly by Ginzburg and Kumar, as well as many new pointed Hopf algebras. We also show that in general the cohomology ring of a Hopf algebra in a braided category is braided commutative. As a consequence we obtain some further information about the structure of the cohomology ring of a finite dimensional pointed Hopf algebra and its related Nichols algebra.Comment: 36 pages, references adde

    Graded Hecke algebras for disconnected reductive groups

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    We introduce graded Hecke algebras H based on a (possibly disconnected) complex reductive group G and a cuspidal local system L on a unipotent orbit of a Levi subgroup M of G. These generalize the graded Hecke algebras defined and investigated by Lusztig for connected G. We develop the representation theory of the algebras H. obtaining complete and canonical parametrizations of the irreducible, the irreducible tempered and the discrete series representations. All the modules are constructed in terms of perverse sheaves and equivariant homology, relying on work of Lusztig. The parameters come directly from the data (G,M,L) and they are closely related to Langlands parameters. Our main motivation for considering these graded Hecke algebras is that the space of irreducible H-representations is canonically in bijection with a certain set of "logarithms" of enhanced L-parameters. Therefore we expect these algebras to play a role in the local Langlands program. We will make their relation with the local Langlands correspondence, which goes via affine Hecke algebras, precise in a sequel to this paper.Comment: Theorem 3.4 and Proposition 3.22 in version 1 were not entirely correct as stated. This is repaired in a new appendi

    Active video games: An opportunity for enhanced learning and positive health effects?

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    Active video games are an emerging genre of electronic games that provide engaging exercise experiences by combining physical exertion with interactive game play. As such they have attracted increased interest from health promotion professionals to reduce sedentary behavior, increase physical activity, and improve health outcomes such as body composition. However their potential for enhancing the educational experience has not been extensively explored. This paper provides a brief overview of active video game research to date and outlines opportunities for future research. Specifically, we highlight the need to develop a conceptual framework to better understand the determinants, mediators, moderators, and consequences of active video gaming and integrate learning and health outcomes. We propose that active video games can be a key part of a wider “digital” supportive environment where education and health researchers and professionals work with, rather than against, video game technologies to promote learning and health

    A Rapid, Inexpensive High Throughput Screen Method for Neurite Outgrowth

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    Neurite outgrowth assays are the most common phenotypic screen to assess chemical effects on neuronal cells. Current automated assays involve expensive equipment, lengthy sample preparation and handling, costly reagents and slow rates of data acquisition and analysis. We have developed a high throughput screen (HTS) for neurite outgrowth using a robust neuronal cell model coupled to fast and inexpensive visualization methods, reduced data volume and rapid data analysis. Neuroscreen-1 (NS-1) cell, a subclone of PC12, possessing rapid growth and enhanced sensitivity to NGF was used as a model neuron. This method reduces preparation time by using cells expressing GFP or native cells stained with HCS CellMask™ Red in a multiplexed 30 min fixation and staining step. A 2x2 camera binning process reduced both image data files and analysis times by 75% and 60% respectively, compared to current protocols. In addition, eliminating autofocus steps during montage generation reduced data collection time. Pharmacological profiles for stimulation and inhibition of neurite outgrowth by NGF and SU6656 were comparable to current standard method utilizing immunofluorescence detection of tubulin. Potentiation of NGF-induced neurite outgrowth by members of a 1,120-member Prestwick compound library as assayed using this method identified six molecules, including etoposide, isoflupredone acetate, fludrocortisone acetate, thioguanosine, oxyphenbutazone and gibberellic acid, that more than doubled the neurite mass primed by 2 ng/ml NGF. This simple procedure represents an important routine approach in high throughput screening of large chemical libraries using the neurite outgrowth phenotype as a measure of the effects of chemical molecules on neuronal cells

    Effectiveness of general practitioner-delivered nutrition care interventions on dietary and health outcomes in adults with diet-related chronic conditions: a systematic review protocol.

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    OBJECTIVE: This systematic review will evaluate the effectiveness of nutrition care interventions delivered by general practitioners versus usual care or no care on dietary and health outcomes in adults with diet-related chronic conditions or risk states. INTRODUCTION: General practitioners are usually the first contacts in the health care system for patients with diet-related chronic conditions. While there is some evidence that general practitioners can be effective in delivering nutrition care for a number of outcomes, to inform future care, an update of the evidence is required as well as an examination of which components are associated with positive outcomes. INCLUSION CRITERIA: Published studies will be included if they report on adults with or at risk of diet-related chronic conditions; one-on-one nutrition care interventions individually delivered by general practitioners during primary care consultations; usual or no care as comparators; dietary and/or health outcomes with a minimum three-month follow-up; and randomized controlled trials. Included studies will be available in, or able to be translated into, English and will have no date restrictions. METHODS: The databases to be searched will include CINAHL, Embase, MEDLINE, and ProQuest Nursing and Allied Health. Following deduplication, two reviewers will independently screen the titles and abstracts in Covidence, followed by the full texts of potentially relevant studies. Disagreements will be resolved through discussion or with a third reviewer. Included studies will be critically appraised and data will be extracted using a modified JBI tool. Findings will be reported in tables and narrative synthesis, and pooled with statistical meta-analysis, where possible. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42021289011
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