434 research outputs found

    Pre-service K-8 Teachers’ Professional Noticing and Strategy Evaluation Skills: An Exploratory Study

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    This study sheds light on three teaching competencies: Pre-service teachers’ (PSTs’) professional noticing of student mathematical reasoning and strategies, their ability to assess the validity of student reasoning and strategies, and to select student strategy for class discussion. Our results reveal that PSTs with strong awareness of mathematically significant aspects of student reasoning and strategies (focused noticing) were better positioned to assess the validity of student reasoning and strategies. PSTs with higher strategy evaluation skills were more likely to choose the strategy to engage class in justification or to advance students’ conceptual understanding compared to PSTs with low strategy evaluation skills

    Sheared Ising models in three dimensions

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    The nonequilibrium phase transition in sheared three-dimensional Ising models is investigated using Monte Carlo simulations in two different geometries corresponding to different shear normals. We demonstrate that in the high shear limit both systems undergo a strongly anisotropic phase transition at exactly known critical temperatures T_c which depend on the direction of the shear normal. Using dimensional analysis, we determine the anisotropy exponent theta=2 as well as the correlation length exponents nu_parallel=1 and nu_perp=1/2. These results are verified by simulations, though considerable corrections to scaling are found. The correlation functions perpendicular to the shear direction can be calculated exactly and show Ornstein-Zernike behavior.Comment: 6 pages, 3 figure

    New algorithm for the computation of the partition function for the Ising model on a square lattice

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    A new and efficient algorithm is presented for the calculation of the partition function in the S=±1S=\pm 1 Ising model. As an example, we use the algorithm to obtain the thermal dependence of the magnetic spin susceptibility of an Ising antiferromagnet for a 8×88\times 8 square lattice with open boundary conditions. The results agree qualitatively with the prediction of the Monte Carlo simulations and with experimental data and they are better than the mean field approach results. For the 8×88\times 8 lattice, the algorithm reduces the computation time by nine orders of magnitude.Comment: 7 pages, 3 figures, to appear in Int. J. Mod. Phys.

    A Proposal for a Problem-Driven Mathematics Curriculum Framework

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    A framework for a problem-driven mathematics curriculum is proposed, grounded in the assumption that students learn mathematics while engaged in complex problem-solving activity. The framework is envisioned as a dynamic technologicallydriven multi-dimensional representation that can highlight the nature of the curriculum (e.g., revealing the relationship among modeling, conceptual, and procedural knowledge), can be used for programmatic, classroom and individual assessment, and can be easily revised to reflect ongoing changes in disciplinary knowledge development and important applications of mathematics. The discussion prompts ideas and questions for future development of the envisioned software needed to enact such a framework

    Domestic water consumption monitoring and behaviour intervention by employing the internet of things technologies

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    As the water resource is becoming scarce, conservation of water has a high priority around the globe, study on water management and conservation becomes an important research problem. People are increasingly becoming more individual households, which tend to be less efficient, requiring more resources per capita than larger households. In order to address these challenges, this paper presents the achievements of monitoring domestic water consumption at the appliance level and intervening people's water usage behavior which have been made in ISS-EWATUS (http://www.issewatus.eu), an European Commission funded FP7 project. The water amount consumed by every household appliance is wirelessly recorded with the exact consumption time and stored in a central database. People's water consumption behavior is likely affected by the real-time water consumption awareness, instant practical advices regarding water-saving activities and classification of water consumption behavior for individuals, all of which are provided by a decision support system deployed as a mobile application in a tablet or any other mobile devices. Only the enhanced water consumption awareness is presented in this paper due to the space limitation. The integrated monitoring and decision support system has been deployed and in use in Sosnowiec in Poland and Skiathos in Greece since March 2015. The domestic water consumption monitoring system at appliance level and the local DSS for affecting people's water consumption behavior are innovative and have little seen before according to the knowledge of the authors.This work is part of the ISS-EWATUS project (www.issewatus.eu) and has been funded by the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no (619228). Appreciation also goes to our former research associates Dr Xi Chen, Dr Xiaomin Chen, Dr Kim Perren, and Dr Yixing Shan who have worked in Loughborough University on the project at various stages

    Near threshold eta meson production in the d+d->alpha+eta reaction

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    The d+d->alpha+eta reaction has been investigated near threshold using the ANKE facility at COSY-Juelich. Both total and differential cross sections have been measured at two excess energies, Q=2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q=-2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for determination of the s-wave eta-alpha scattering length are discussed.Comment: 8pp, fig.3 added, normalisation in eq.4.1 correcte

    Comparison of various models of Monte Carlo geant 4 code in simulations of prompt gamma production

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    In this paper, results of simulations of the gamma-ray production in reactions with 70 MeV protons in a target of PMMA are presented. The data obtained by means of two versions of Geant 4 software, 9.3 and 10.01, have shown significant differences in the gamma-ray spectra. The comparison between the calculated spectra and the measured ones has been carried out. The tested versions do not give satisfactory agreement with the experimental result. The reason of the performed verification was the planned application of this simulation toolkit for the preparation of in vivo dosimetry based on the prompt gamma-ray measurements for the proton therapy

    MATHICSE Technical Report: Constraint-Aware Neural Networks for Riemann Problems

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    Neural networks are increasingly used in complex (data-driven) simulations as surrogates or for accelerating the computation of classical surrogates. In many applications physical constraints, such as mass or energy conservation, must be satised to obtain reliable results. However, standard machine learning algorithms are generally not tailored to respect such constraints. We propose two different strategies to generate constraint-aware neural networks. We test their performance in the context of front-capturing schemes for strongly nonlinear wave motion in compressible uid ow. Precisely, in this context so-called Riemann problems have to be solved as surrogates. Their solution describes the local dynamics of the captured wave front in numerical simulations. Three model problems are considered: a cubic ux model problem, an isothermal two-phase ow model, and the Euler equations. We demonstrate that a decrease in the constraint deviation correlates with low discretization errors for all model problems, in addition to the structural advantage of fullfilling the constraint

    Study of three-nucleon dynamics in the dp breakup collisions using the WASA detector

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    An experiment to investigate the 1H(d; pp)n breakup reaction using a deuteron beam of 300, 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jülich. As a first step, the data collected at the beam energy of 340MeV are analysed, with a focus on the proton–proton coincidences registered in the Forward Detector. Elastically scattered deuterons are used for precise determination of the luminosity. The main steps of the analysis, including energy calibration, particle identification (PID) and efficiency studies, and their impact on the final accuracy of the result, are discussed

    Local and Regional Indian Summer Monsoon Precipitation Dynamics During Termination II and the Last Interglacial

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    To date Indian summer monsoon (ISM) dynamics have been assessed by changes in stalagmite δ18O. However, stalagmite δ18O is influenced by multiple environmental factors (e.g., atmospheric moisture transport, rainfall amount at the study site, and ISM seasonality), precluding simple and clear reconstructions of rainfall amount or variability. This study aims to disentangle these environmental factors by combining δ18O, δ44Ca, and elemental data from a stalagmite covering Termination II and the last interglacial from Mawmluh Cave, NE India, to produce a semiquantitative reconstruction of past ISM rainfall. We interpret δ18O as a mixed signal of rainfall source dynamics and rainfall amount and coupled δ44Ca and X/Ca ratios as indicators of local infiltration rate and prior calcite precipitation in the karst zone. The wettest conditions in our studied interval (135 and 100 kyrs BP; BP = before present, with the present being 1950 CE) occurred during Marine Isotope Stage 5e. Our multiproxy data set suggests a likely change in seasonal distribution of Marine Isotope Stage 5e rainfall compared to the Holocene; the wet season was longer with higher‐than‐modern dry season rainfall. Using the last interglacial as an analogue for future anthropogenic warming, our data suggest a more erratic ISM behavior in a warmer world
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