177 research outputs found

    The Metaverse as a Museum Practice

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    From the design of interactive processes to digital exhibition spaces, we will explore the potentialities and limits of the use of the metaverse through three case studies by examining the relationship of continuity/ discontinuity between the physical museum and the digital museum

    Cardiovascular fitness influences self-concept during the adolescence

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    Self-concept is one of the most researched constructs within the framework of educational psychology, psychology of the personality, and social psychology. Self-concept can be defined as the perception that an individual has of him or herself, with contents that are both descriptive, as well as evaluative 1. In the field of sport and exercise, physical selfconcept is also considered playing a considerable role in sports performance 2. The present study aims to investigate the relationship between sports practice, cardiovascular fitness and physical self-concept in adolescents.Ciencias de la Actividad Física y del Deport

    Quantum-Phase Transitions of Interacting Bosons and the Supersolid Phase

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    We investigate the properties of strongly interacting bosons in two dimensions at zero temperature using mean-field theory, a variational Ansatz for the ground state wave function, and Monte Carlo methods. With on-site and short-range interactions a rich phase diagram is obtained. Apart from the homogeneous superfluid and Mott-insulating phases, inhomogeneous charge-density wave phases appear, that are stabilized by the finite-range interaction. Furthermore, our analysis demonstrates the existence of a supersolid phase, in which both long-range order (related to the charge-density wave) and off-diagonal long-range order coexist. We also obtain the critical exponents for the various phase transitions.Comment: RevTex, 20 pages, 10 PostScript figures include

    Superfluids and Supersolids on Frustrated 2D Lattices

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    We study the ground state of hard-core bosons with nearest-neighbor hopping and nearest-neighbor interactions on the triangular and Kagom\'e lattices by mapping to a system of spins (S=12S={1\over2}), which we analyze using spin-wave theory. We find that the both lattices display superfluid and supersolid (a coexistence of superfluid and solid) order as the parameters and filling are varied. Quantum fluctuations seem large enough in the Kagom\'e system to raise the interesting possibility of a disordered ground state.Comment: Latex format, 24 figures available by email upon request. Submitted to Physical Review

    Evaluación de la actividad antibacteriana in vitro de los extractos de Caesalpinia spinosa “tara” y Eucalyptus sp. “eucalipto”

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    The antibacterian activity of extract of Caesalpinia spinosa and Eucalyptus sp. "eucalipto" was valued using bacterials capes gram positives (Staphylococcus aureus and Bacyllus subtilis) and gram negatives (Escherichia coli, Klebsiella sp, Shigella flexneri).For the investigation was used as extraction solvent a mixture of aIcohol-acetona (1:1), the biological activity of the obtained extracts was valued using the disc diffusion technique.The fruit peel of Caesalpinia spinosa and the leaves of Eucalyptus sp show a selective activity over the valued grampositives bacteriums.Se evalúo in vitro la actividad antibacteriana de extractos de Caesalpinia spinosa "tara" y Eucalyptus sp. "eucalipto" utilizando cepas bacterianas Gram positivas (Staphylococcus aureus y Bacillus subtilis) y Gram negativas (Escherichia coli, Klebsiella sp. y Shigella flexneri). Se utilizó como solvente de extracción una mezcla de alcohol-acetona (1:1) y la actividad biológica de los extractos obtenidos se evaluó mediante la técnica de difusión en disco.La cáscara del fruto de Caesalpinia spinosa y las hojas del Eucalyptus sp. mostraron una actividad selectiva sobre las bacterias Gram positivas evaluadas

    Solid 4He and the Supersolid Phase: from Theoretical Speculation to the Discovery of a New State of Matter? A Review of the Past and Present Status of Research

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    The possibility of a supersolid state of matter, i.e., a crystalline solid exhibiting superfluid properties, first appeared in theoretical studies about forty years ago. After a long period of little interest due to the lack of experimental evidence, it has attracted strong experimental and theoretical attention in the last few years since Kim and Chan (Penn State, USA) reported evidence for nonclassical rotational inertia effects, a typical signature of superfluidity, in samples of solid 4He. Since this "first observation", other experimental groups have observed such effects in the response to the rotation of samples of crystalline helium, and it has become clear that the response of the solid is extremely sensitive to growth conditions, annealing processes, and 3He impurities. A peak in the specific heat in the same range of temperatures has been reported as well as anomalies in the elastic behaviour of solid 4He with a strong resemblance to the phenomena revealed by torsional oscillator experiments. Very recently, the observation of unusual mass transport in hcp solid 4He has also been reported, suggesting superflow. From the theoretical point of view, powerful simulation methods have been used to study solid 4He, but the interpretation of the data is still rather difficult; dealing with the question of supersolidity means that one has to face not only the problem of the coexistence of quantum coherence phenomena and crystalline order, exploring the realm of spontaneous symmetry breaking and quantum field theory, but also the problem of the role of disorder, i.e., how defects, such as vacancies, impurities, dislocations, and grain boundaries, participate in the phase transition mechanism.Comment: Published on J. Phys. Soc. Jpn., Vol.77, No.11, p.11101

    Classification of a supersolid: Trial wavefunctions, Symmetry breakings and Excitation spectra

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    A state of matter is characterized by its symmetry breaking and elementary excitations. A supersolid is a state which breaks both translational symmetry and internal U(1) U(1) symmetry. Here, we review some past and recent works in phenomenological Ginsburg-Landau theories, ground state trial wavefunctions and microscopic numerical calculations. We also write down a new effective supersolid Hamiltonian on a lattice. The eigenstates of the Hamiltonian contains both the ground state wavefunction and all the excited states (supersolidon) wavefunctions. We contrast various kinds of supersolids in both continuous systems and on lattices, both condensed matter and cold atom systems. We provide additional new insights in studying their order parameters, symmetry breaking patterns, the excitation spectra and detection methods.Comment: REVTEX4, 19 pages, 3 figure

    Genetic and environmental influences on the relation between attention problems and Attention Deficit Hyperactivity Disorder.

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    Objective: The assessment of symptoms of ADHD in children is usually based on a clinical interview or a behavior checklist. The aim of the present study is to investigate the extent to which these instruments measure an underlying construct and to estimate the genetic and environmental influences on individual differences in ADHD. Methods: Maternal ratings were collected on 10,916 twins from 5,458 families. Child Behavior Checklist (CBCL) ratings were available for 10,018, 6,565, and 5,780 twins at the ages 7, 10, and 12, respectively. The Conners Rating Scale (4,887 twins) and the DSM interview (1,006 twins) were completed at age 12. The magnitude of genetic and environmental influences on the variance of the three measures of ADHD and the covariance among the three measures of ADHD was obtained. Results: Phenotypic correlations range between .45 and .77. Variances and covariances of the measurements were explained mainly by genetic influences. The model that provided the best account of the data included an independent pathway for additive and dominant genetic effects. The genetic correlations among the measures collected at age 12 varied between .63 and 1.00. Conclusions: The genetic overlap between questionnaire ratings and the DSM-IV diagnosis of ADHD is high. Clinical and research implications of these findings are presented

    Person-Related Protective and Vulnerability Factors of Psychopathology Symptoms in Non-Clinical Adolescents

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    Psychopathology in youths is thought to originate from a dynamic interplay of a variety of protective and vulnerability factors. In this study, a large multi-ethnic sample of non-clinical adolescents (N = 376) completed questionnaires for measuring a wide range of person-related protective and vulnerability factors as well as psychopathology symptoms, in order to explore (a) the relations among various protective and vulnerability factors, and (b) the unique contributions of these protective and vulnerability factors to different types of psychological problems. Results indicated that the overlap among protective and vulnerability factors was quite modest. Further, it was found that factors clustered in theoretically meaningful components reflecting protection, vulnerability, and more specific aspects of coping and social support. Finally, data indicated that each type of psychopathology symptoms was associated with a typical set of protective and vulnerability factors. Although these results should be interpreted with caution because of the cross-sectional nature of the study, they may nevertheless guide future research exploring multifactorial models of psychopathology in youths
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