654 research outputs found

    Chiral Transition of N=4 Super Yang-Mills with Flavor on a 3-Sphere

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    We use the AdS/CFT correspondence to perform a numerical study of a phase transition in strongly-coupled large-Nc N = 4 Super-Yang-Mills theory on a 3-sphere coupled to a finite number Nf of massive N = 2 hypermultiplets in the fundamental representation of the gauge group. The gravity dual system is a number Nf of probe D7-branes embedded in AdS_5 x S^5. We draw the phase diagram for this theory in the plane of hypermultiplet mass versus temperature and identify for temperatures above the Hawking-Page deconfinement temperature a first-order phase transition line across which the chiral condensate jumps discontinuously.Comment: 23 pages, 15 figures, minor corrections, reference added, nine figures improved, no change in results or conclusions; expanded discussion of fixing finite counterterms in section 3.3, figures updated, no changes to conclusion

    Heuristic Learning as a Method for Improving Students’ Teamwork Skills in Physical Education

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    Transversal skills are the knowledge, skills, and personal qualities that are currently needed to meet the demands of the working world and everyday life. Schools have the task of equipping students with these skills, working not only on disciplinary goals but also on operational–behavioral goals. In 2018, the European Union adopted new recommendations on eight key competencies for lifelong learning and asked schools to implement new methods to develop these recommendations. To be successful, it is necessary to stimulate students’ development of these competences, which are also called soft skills, from the earliest years of the school experience. Physical education (PE) is called upon to make its contribution. In Italy, the two teaching methods used during PE classes are prescriptive teaching and heuristic learning. It is not clear which of the two methods is the most effective in improving soft skills, especially the skills involved in teamwork. The objective of this article was to compare the effects of these two teaching methods on students’ teamwork skills during PE classes in primary schools. After verifying the normality of the data, a Student’s t-test for dependent samples was performed to assess pre-test and post-test differences in each of two groups, while a Student’s t-test for independent samples was performed to compare the two groups after 3 months. Heuristic learning proved to be the most effective method for improving teamwork skills. The results may make an important contribution to future teacher training on the most effective teaching methods for developing students’ soft skill

    04/18/1997 - Collective Soul To Perform At EIU.pdf

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    International audienceâ–ş We present a spectroscopic method to discriminate biotic from abiotic carbonates. â–ş Infrared spectral modifications induced by thermal processing are investigated. â–ş We analyse carbonate samples with no evidences of biomineralization. â–ş Our method is a powerful tool for the search of life on Mars

    The QCD phase diagram at nonzero quark density

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    We determine the phase diagram of QCD on the \mu-T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations are carried out on N_t =6,8 and 10 lattices generated with a Symanzik improved gauge and stout-link improved 2+1 flavor staggered fermion action using physical quark masses. After carrying out the continuum extrapolation we find that both quantities result in a similar curvature of the transition line. Furthermore, our results indicate that in leading order the width of the transition region remains essentially the same as the chemical potential is increased.Comment: 12 pages, 6 figure

    Holographic Roberge-Weiss Transitions II: Defect Theories and the Sakai-Sugimoto Model

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    We extend the work of Aarts et al., including an imaginary chemical potential for quark number into the Sakai-Sugimoto model and codimension k defect theories. The phase diagram of these models are a function of three parameters, the temperature, chemical potential and the asymptotic separation of the flavour branes, related to a mass for the quarks in the boundary theories. We compute the phase diagrams and the pressure due to the flavours of the theories as a function of these parameters and show that there are Roberge-Weiss transitions in the high temperature phases, chiral symmetry restored for the Sakai-Sugimoto model and deconfined for the defect models, while at low temperatures there are no Roberge-Weiss transitions. In all the models we consider the transitions between low and high temperature phases are first order, hence the points where they meet the Roberge-Weiss lines are triple points. The pressure for the defect theories scales in the way we expect from dimensional analysis while the Sakai-Sugimoto model exhibits unusual scaling. We show that the models we consider are analytic in \mu^2 when \mu^2 is small.Comment: 39 pages, 12 figures. references added, Sakai-Sugimoto section revised, version to appear in JHE

    Low-energy theorems of QCD and bulk viscosity at finite temperature and baryon density in a magnetic field

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    The nonperturbative QCD vacuum at finite temperature and a finite baryon density in an external magnetic field is studied. Equations relating nonperturbative condensates to the thermodynamic pressure for T≠0T\neq 0, μq≠0\mu_q \neq 0 and H≠0H\neq 0 are obtained, and low-energy theorems are derived. A bulk viscosity ζ(T,μ,H)\zeta(T, \mu, H) is expressed in terms of basic thermodynamical quantities describing the quark-gluon matter at T≠0T\neq 0, μq≠0\mu_q \neq 0, and H≠0H\neq 0. Various limiting cases are also considered.Comment: 12 pages; v2: title changed, new section about bulk viscosity and new references added; v3: new discussion adde

    ResoluciĂłn de advecciĂłn difusiĂłn en multi-GPGPU

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    En este trabajo se presenta la solución del problema de advección difusión mediante un enfoque multi-GPGPU con GPUs ubicados en diferentes nodos del clúster que interactúan mediante el protocolo MPI. La idea es usar descomposición de dominio de modo que cada GPU resuelve una parte del dominio computacional y MPI es usado para intercambiar datos de borde. Los solvers están basados en los métodos de Gradientes Conjugados Cuadrado (CGS) y Gradientes Biconjugado Estabilizado (Bi-CGSTAB) que son métodos usados para resolver problemas donde la matriz A no es simétrica como es el caso del problema de advección difusión. La no simetría aparece debido a la discretización del término advectivo en el contexto del método de volúmenes finitos sobre mallas estructuradas cartesianas de paso constante. Se analizan varias opciones de discretización del término advectivo como ser diferencias centradas, up wind y esquemas de alto orden. Se presenta un análisis teórico de cada uno de estos esquemas y su performance computacional en multi-GPGPU. Se presenta además las propiedades de convergencia de los métodos presentados y su performance computacional en multi-GPGPU.Publicado en: Mecánica Computacional vol. XXXV, no. 10.Facultad de Ingenierí

    Trans-disciplinary Collaboration to Enhance Coastal Resilience: Envisioning a National Community Modeling Initiative

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    This section presents a synthesis of the major outcomes from the coastal resilience workshops. This paper is based on the presentations and discussions that have been guided by the Chair and numerous stakeholders such as university researchers, Non Governmental Organizations, and federal, state, and local governments. SURA’s workshop series promotes collaboration and fully-integrated processes, and it should be noted that the actual workshop is only a first step; the follow-up work is likely to continue for years. The major results from this workshop relate to the development of trans-disciplinary approaches that help a community to bounce back after hazardous events such as hurricanes, coastal storms, and flooding – rather than simply rebuilding in the aftermath. The workshops have included participants from academia, industry, and government. They provide opportunity to share coastal resilience research and projects focused on helping the community to rebound quickly from climate and extreme weather related events, including sea level rise. The purpose of the paper is to showcase how social and natural scientists can collaborate to reduce the negative human health, environmental, and economic effects of coastal hazards
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