76 research outputs found

    Didactic Conception Of Serious Games: On The Linking Of Game And Learning Offers

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    Serious Games versuchen Spielen mit Lernen zu verbinden. Der Beitrag problematisiert die Machbarkeit einer solchen VerknĂŒpfung in digitalen Welten und diskutiert verschiedene didaktische Konzepte einer Nutzbarmachung digitaler Spiele fĂŒr das Lernen und Lehren. Ausgehend von einer Analyse des Erlernens von Spielen werden drei didaktische Konzepte von Serious Games im Hinblick auf ihre didaktischen Potenziale untersucht: (1) der unmittelbare Transfer von Wissen, das im Spiel erworben wird (keine zusĂ€tzliche Didaktisierung), (2) Didaktisierung durch Einbettung des Spiels in einer Lernsituation oder (3) Didaktisierung durch Einbettung von Lernaufgaben in ein Spiel. Ergebnisse zur Nutzung von Spielen, bei denen Lernaufgaben in eine Spielwelt eingebettet sind, zeigen, dass Personen die Aufnahme von Wissen in einem expliziten Lernmodus eher zu reduzieren versuchen, um möglichst zĂŒgig wieder in den Spielmodus zu wechseln. Diskutiert werden die Konsequenzen dieser Problematik fĂŒr die didaktische Konzeption von Serious Games.Serious games try to combine playing with learning. The article problematises the feasibility of such a link in digital worlds and discusses various didactic concepts of making digital games usable for learning and teaching. Based on an analysis of the learning of games, three didactic concepts of serious games are examined with regard to their didactic potentials: (1) the direct transfer of knowledge acquired in the game (no additional didacticisation), (2) didacticisation by embedding the game in a learning situation or (3) didacticisation by embedding learning tasks in a game. Results on the use of games in which learning tasks are embedded in a game world show that people tend to try to reduce the absorption of knowledge in an explicit learning mode in order to switch back to the game mode as quickly as possible. The consequences of this problem for the didactic conception of serious games are discussed

    Vegetation and climate history in the Carpathians during MIS 3-2 – a multi-proxy study of a sediment sequence from MohoƟ crater, Romania

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    We present a new record of vegetation and climate history derived from a multiproxy investigation of sediments recovered from the in-filled MohoƟ crater (46°05' N; 25°55' E) located within the Ciomadul volcano complex (Romania). To date, the 30-m long sediment core, covering MIS 3 to present provides one of the longest lacustrine records from the Carpathian regio

    Hydrogen Motion in Magnesium Hydride by NMR

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    In coarse-grained MgH2, the diffusive motion of hydrogen remains too slow (<10^5 hops s^−1) to narrow the H NMR line up to 400 °C. Slow-motion dipolar relaxation time T1D measurements reveal the motion, with hopping rate ωH from 0.1 to 430 s^−1 over the range of 260 to 400 °C, the first direct measurement of H hopping in MgH2. The ωH data are described by an activation energy of 1.72 eV (166 kJ/mol) and attempt frequency of 2.5 × 10^15 s^−1. In ball-milled MgH2 with 0.5 mol % added Nb2O5 catalyst, line-narrowing is evident already at 50 °C. The line shape shows distinct broad and narrow components corresponding to immobile and mobile H, respectively. The fraction of mobile H grows continuously with temperature, reaching ∌30% at 400 °C. This demonstrates that this material’s superior reaction kinetics are due to an increased rate of H motion, in addition to the shorter diffusion paths from ball-milling. In ball-milled MgH2 without additives, the line-narrowed component is weaker and is due, at least in part, to trapped H2 gas. The spin−lattice relaxation rates T1^−1 of all materials are compared, with ball-milling markedly increasing T1^−1. The weak temperature dependence of T1^−1 suggests a mechanism with paramagnetic relaxation centers arising from the mechanical milling

    Experimental application to a water delivery canal of a distributed MPC with stability constraints

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    In this work, a novel distributed MPC algorithm, denoted D-SIORHC, is applied to upstream local control of a pilot water delivery canal. The D-SIORHC algorithm is based on MPC control agents that incorporate stability constraints and communicate only with their adjacent neighbors in order to achieve a coordinated action. Experimental results that show the effect of the parameters configuring the local controllers are presented

    Genetic Variance and Covariance Components for Feed Intake, Average Daily Gain, and Postweaning Gain in Growing Beef Cattle

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    Feed is the greatest cost for a beef cattle production enterprise. Data collection to determine feed efficiency of animals is also costly, because both gain and intake records are needed to calculate feed efficiency. Electronic intake monitoring systems such as GrowSafe or Insentec to collect feed intake data are expensive and thus limit the number of animals that can be tested. Scientists have worked to pinpoint optimal test durations for collecting both weight gain and feed intake records to lessen costs. A 70-day performance test is currently recommended for accurate calculation of efficiency, with growth data as the limiting factor. Research has suggested that a 35-day test is adequate to measure feed intake, but a test period of at least 70 days is suggested to measure gain with sufficient accuracy. The objective of this study was to estimate genetic parameters for growth and intake traits with particular attention to the relationship between on-test average daily gain (ADG) and national cattle evaluation postweaning gain (PWG). If the correlation between these two traits is strong, it could allow for the use of PWG as a proxy for ADG in the genetic evaluation of feed efficiency. This substitution would allow producers to reduce the length of the test required to measure feed intake accurately

    Dynamic scaling for 2D superconductors, Josephson junction arrays and superfluids

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    The value of the dynamic critical exponent zz is studied for two-dimensional superconducting, superfluid, and Josephson Junction array systems in zero magnetic field via the Fisher-Fisher-Huse dynamic scaling. We find z≃5.6±0.3z\simeq5.6\pm0.3, a relatively large value indicative of non-diffusive dynamics. Universality of the scaling function is tested and confirmed for the thinnest samples. We discuss the validity of the dynamic scaling analysis as well as the previous studies of the Kosterlitz-Thouless-Berezinskii transition in these systems, the results of which seem to be consistent with simple diffusion (z=2z=2). Further studies are discussed and encouraged.Comment: 19 pages in two-column RevTex, 8 embedded EPS figure

    Language, Religion, and Ethnic Civil War

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    Are certain ethnic cleavages more conflict-prone than others? While only few scholars focus on the contents of ethnicity, most of those who do argue that political violence is more likely to occur along religious divisions than linguistic ones. We challenge this claim by analyzing the path from linguistic differences to ethnic civil war along three theoretical steps: (1) the perception of grievances by group members, (2) rebel mobilization, and (3) government accommodation of rebel demands. Our argument is tested with a new data set of ethnic cleavages that records multiple linguistic and religious segments for ethnic groups from 1946 to 2009. Adopting a relational perspective, we assess ethnic differences between potential challengers and the politically dominant group in each country. Our findings indicate that intrastate conflict is more likely within linguistic dyads than among religious ones. Moreover, we find no support for the thesis that Muslim groups are particularly conflict-prone

    Novel missense mutations in the glycine receptor ÎČ subunit gene (GLRB) in startle disease

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    Startle disease is a rare, potentially fatal neuromotor disorder characterized by exaggerated startle reflexes and hypertonia in response to sudden unexpected auditory, visual or tactile stimuli. Mutations in the GlyR alpha(1) subunit gene (GLRA1) are the major cause of this disorder, since remarkably few individuals with mutations in the GlyR beta subunit gene (GLRB) have been found to date. Systematic DNA sequencing of GLRB in individuals with hyperekplexia revealed new missense mutations in GLRB, resulting in M177R, L285R and W310C substitutions. The recessive mutation M177R results in the insertion of a positively-charged residue into a hydrophobic pocket in the extracellular domain, resulting in an increased EC50 and decreased maximal responses of alpha(1)beta GlyRs. The de novo mutation L285R results in the insertion of a positively-charged side chain into the pore-lining 9' position. Mutations at this site are known to destabilize the channel closed state and produce spontaneously active channels. Consistent with this, we identified a leak conductance associated with spontaneous GlyR activity in cells expressing alpha(1)beta(L285R) GlyRs. Peak currents were also reduced for alpha(1)beta(L285R) GlyRs although glycine sensitivity was normal. W310C was predicted to interfere with hydrophobic side-chain stacking between M1, M2 and M3. We found that W310C had no effect on glycine sensitivity, but reduced maximal currents in alpha(1)beta GlyRs in both homozygous (alpha(1)beta(W310C)) and heterozygous (alpha(1)beta beta(W310C)) stoichiometries. Since mild startle symptoms were reported in W310C carriers, this may represent an example of incomplete dominance in startle disease, providing a potential genetic explanation for the 'minor' form of hyperekplexia. (C) 2012 Elsevier Inc. All rights reserved

    Estimates of live-tree carbon stores in the Pacific Northwest are sensitive to model selection

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    <p>Abstract</p> <p>Background</p> <p>Estimates of live-tree carbon stores are influenced by numerous uncertainties. One of them is model-selection uncertainty: one has to choose among multiple empirical equations and conversion factors that can be plausibly justified as locally applicable to calculate the carbon store from inventory measurements such as tree height and diameter at breast height (DBH). Here we quantify the model-selection uncertainty for the five most numerous tree species in six counties of northwest Oregon, USA.</p> <p>Results</p> <p>The results of our study demonstrate that model-selection error may introduce 20 to 40% uncertainty into a live-tree carbon estimate, possibly making this form of error the largest source of uncertainty in estimation of live-tree carbon stores. The effect of model selection could be even greater if models are applied beyond the height and DBH ranges for which they were developed.</p> <p>Conclusions</p> <p>Model-selection uncertainty is potentially large enough that it could limit the ability to track forest carbon with the precision and accuracy required by carbon accounting protocols. Without local validation based on detailed measurements of usually destructively sampled trees, it is very difficult to choose the best model when there are several available. Our analysis suggests that considering tree form in equation selection may better match trees to existing equations and that substantial gaps exist, in terms of both species and diameter ranges, that are ripe for new model-building effort.</p
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