16,295 research outputs found

    Scientific Argumentation as a Foundation for the Design of Inquiry-Based Science Instruction

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    Despite the attention that inquiry has received in science education research and policy, a coherent means for implementing inquiry in the classroom has been missing [1]. In recent research, scientific argumentation has received increasing attention for its role in science and in science education [2]. In this article, we propose that organizing a unit of instruction around building a scientific argument can bring inquiry practices together in the classroom in a coherent way. We outline a framework for argumentation, focusing on arguments that are central to science—arguments for the best explanation. We then use this framework as the basis for a set of design principles for developing a sequence of inquiry-based learning activities that support students in the construction of a scientific argument. We show that careful analysis of the argument that students are expected to build provides designers with a foundation for selecting resources and designing supports for scientific inquiry. Furthermore, we show that creating multiple opportunities for students to critique and refine their explanations through evidence-based argumentation fosters opportunities for critical thinking, while building science knowledge and knowledge of the nature of science

    More on Electric Dipole Moment Constraints on Phases in the Constrained MSSM

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    We reconsider constraints on \cp-violating phases in the Constrained Minimal Supersymmetric Standard Model. We include the recent calculations of Ibrahim and Nath on the chromoelectric and purely gluonic contributions to the quark electric dipole moment and combine cosmological limits on gaugino masses with experimental bounds on the neutron (and electron) electric dipole moments. The constraint on the phase of the Higgs mixing mass μ\mu, |\thm|, is dependent on the value of the trilinear mass parameter, AA, in the model and on tanβ\tan \beta. For values of |A| < 300 \gev at the GUT scale, we find |\thm|/\pi \la 0.05, while for |A| < 1500 \gev, |\thm|/\pi \la 0.3. Thus, we find that in principle, large CP violating phases are compatible with the bounds on the electric dipole moments of the neutron and electron, as well as remaining compatible with the cosmological upper bound on the relic density of neutralinos. The other \cp-violating phase \tha is essentially unconstrained.Comment: 11 pages in LaTeX + 4 postscript figures, uses epsf.sty. Added two references, clarified figures. Accepted to Physics Letter

    Instanton constituents in the O(3) model at finite temperature

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    It is shown that instantons in the O(3) model at finite temperature consist of fractional charge constituents and the (topological) properties of the latter are discussed.Comment: 5 pages, 12 plots in 3 figure

    On Multivariate Records from Random Vectors with Independent Components

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    Let X1,X2,\boldsymbol{X}_1,\boldsymbol{X}_2,\dots be independent copies of a random vector X\boldsymbol{X} with values in Rd\mathbb{R}^d and with a continuous distribution function. The random vector Xn\boldsymbol{X}_n is a complete record, if each of its components is a record. As we require X\boldsymbol{X} to have independent components, crucial results for univariate records clearly carry over. But there are substantial differences as well: While there are infinitely many records in case d=1d=1, there occur only finitely many in the series if d2d\geq 2. Consequently, there is a terminal complete record with probability one. We compute the distribution of the random total number of complete records and investigate the distribution of the terminal record. For complete records, the sequence of waiting times forms a Markov chain, but differently from the univariate case, now the state infinity is an absorbing element of the state space

    BGG resolutions via configuration spaces

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    We study the blow-ups of configuration spaces. These spaces have a structure of what we call an Orlik-Solomon manifold; it allows us to compute the intersection cohomology of certain flat connections with logarithmic singularities using some Aomoto type complexes of logarithmic forms. Using this construction we realize geometrically the sl_2 Bernstein - Gelfand - Gelfand resolution as an Aomoto complex.Comment: Latex, 19 page

    Some Results on Joint Record Events

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    Let X1,X2,X_1,X_2,\dots be independent and identically distributed random variables on the real line with a joint continuous distribution function FF. The stochastic behavior of the sequence of subsequent records is well known. Alternatively to that, we investigate the stochastic behavior of arbitrary Xj,Xk,j<kX_j,X_k,j<k, under the condition that they are records, without knowing their orders in the sequence of records. The results are completely different. In particular it turns out that the distribution of XkX_k, being a record, is not affected by the additional knowledge that XjX_j is a record as well. On the contrary, the distribution of XjX_j, being a record, is affected by the additional knowledge that XkX_k is a record as well. If FF has a density, then the gain of this additional information, measured by the corresponding Kullback-Leibler distance, is j/kj/k, independent of FF. We derive the limiting joint distribution of two records, which is not a bivariate extreme value distribution. We extend this result to the case of three records. In a special case we also derive the limiting joint distribution of increments among records
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