144 research outputs found

    Reliability of the spanish version of Questionnaire of Physical Activity PAQ-C

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    Objetivo. El objetivo de esta investigación ha sido valorar en niños españoles la fiabilidad del cuestionario de actividad física en niños mayores (PAQ-C). Método. Se utilizó como referencia la validación de la versión traducida al castellano del cuestionario de actividad física para adolescentes PAQ-A. En una muestra de 72 niños entre 8 y 14 años, se evaluó la fiabilidad test-retest del cuestionario PAQ-C en 3 mediciones, antes de la clase de educación física (M1), 2 horas después (M2) y al cabo de una semana (M3). La fiabilidad se calculó mediante el coeficiente de correlación intraclase (ICC) y la consistencia interna mediante el Coeficiente α de Cronbach. Resultados: Los valores obtenidos en la puntuación total del cuestionario reflejan un ICC superior a 0.73 en todas las comparaciones, con un intervalo de confianza al 95% que sigue indicando una fiabilidad buena o excelente. La consistencia interna mostró un coeficiente de α = 0,83Background: The aim of this study was to assess the reliability of the PAQ-C questionnaire in spanish older children (PAQ-C). Methods: A proof translation in Spanish of the physical activity questionnaire for teenager PAQ-A, was used as reference. Reliability of the test-retest questionnaire PAQ-C, was evaluated on 72 children aged between 8 and 14 years. Measurements were taken at three different stages: before the physical education class (M1), 2 hours after the lecture (M2) and one week later (M3). Reliability was calculated using the intraclass correlation coefficient (ICC) while the inner consistency by Cronbach's αcoefficient. Results: The results obtained in the overall score of the questionnaire reflect an intraclass coefficient (ICC) higher than 0,73 in every possible comparison giving a confidence interval of 95% which still indicates a good or very good reliability. The inner consistency showed a coefficient of α = 0,8

    La lectura de los autores clásicos en Cataluña durante la época de Carlos III

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    Unraveling the Temporal Dynamics of Reward Signals in Music-Induced Pleasure with TMS

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    Music's ability to induce feelings of pleasure has been the subject of intense neuroscientific research lately. Prior neuroimaging studies have shown that music-induced pleasure engages cortico-striatal circuits related to the anticipation and receipt of biologically relevant rewards/incentives, but these reports are necessarily correlational. Here, we studied both the causal role of this circuitry and its temporal dynamics by applying transcranial magnetic stimulation (TMS) over the left dorsolateral PFC combined with fMRI in 17 male and female participants. Behaviorally, we found that, in accord with previous findings, excitation of fronto-striatal pathways enhanced subjective reports of music-induced pleasure and motivation, whereas inhibition of the same circuitry led to the reduction of both. fMRI activity patterns indicated that these behavioral changes were driven by bidirectional TMS-induced alteration of fronto-striatal function. Specifically, changes in activity in the NAcc predicted modulation of both hedonic and motivational responses, with a dissociation between pre-experiential versus experiential components of musical reward. In addition, TMS-induced changes in the fMRI functional connectivity between the NAcc and frontal and auditory cortices predicted the degree of modulation of hedonic responses. These results indicate that the engagement of cortico-striatal pathways and the NAcc, in particular, is indispensable to experience rewarding feelings from music.SIGNIFICANCE STATEMENT Neuroimaging studies have shown that music-induced pleasure engages cortico-striatal circuits involved in the processing of biologically relevant rewards. Yet, these reports are necessarily correlational. Here, we studied both the causal role of this circuitry and its temporal dynamics by combining brain stimulation over the frontal cortex with functional imaging. Behaviorally, we found that excitation and inhibition of fronto-striatal pathways enhanced and disrupted, respectively, subjective reports of music-induced pleasure and motivation. These changes were associated with changes in NAcc activity and NAcc coupling with frontal and auditory cortices, dissociating between pre-experimental versus experiential components of musical reward. These results indicate that the engagement of cortico-striatal pathways, and the NAcc in particular, is indispensable to experience rewarding feelings from music

    Extended ML: Past, present and future

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    An overview of past, present and future work on the Extended ML formal program development framework is given, with emphasis on two topics of current active research: the semantics of the Extended ML specification language, and tools to support formal program development

    New families of symplectic splitting methods for numerical integration in dynamical astronomy

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    We present new splitting methods designed for the numerical integration of near-integrable Hamiltonian systems, and in particular for planetary N-body problems, when one is interested in very accurate results over a large time span. We derive in a systematic way an independent set of necessary and sufficient conditions to be satisfied by the coefficients of splitting methods to achieve a prescribed order of accuracy. Splitting methods satisfying such (generalized) order conditions are appropriate in particular for the numerical simulation of the Solar System described in Jacobi coordinates. We show that, when using Poincar\'e Heliocentric coordinates, the same order of accuracy may be obtained by imposing an additional polynomial equation on the coefficients of the splitting method. We construct several splitting methods appropriate for each of the two sets of coordinates by solving the corresponding systems of polynomial equations and finding the optimal solutions. The experiments reported here indicate that the efficiency of our new schemes is clearly superior to previous integrators when high accuracy is required.Comment: 24 pages, 2 figures. Revised version, accepted for publication in Applied Numerical Mathematic

    Natural and sail-displaced doubly-symmetric Lagrange point orbits for polar coverage

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    This paper proposes the use of doubly-symmetric, eight-shaped orbits in the circular restricted three-body problem for continuous coverage of the high-latitude regions of the Earth. These orbits, for a range of amplitudes, spend a large fraction of their period above either pole of the Earth. It is shown that they complement Sun-synchronous polar and highly eccentric Molniya orbits, and present a possible alternative to low thrust pole-sitter orbits. Both natural and solar-sail displaced orbits are considered. Continuation methods are described and used to generate families of these orbits. Starting from ballistic orbits, other families are created either by increasing the sail lightness number, varying the period or changing the sail attitude. Some representative orbits are then chosen to demonstrate the visibility of high-latitude regions throughout the year. A stability analysis is also performed, revealing that the orbits are unstable: it is found that for particular orbits, a solar sail can reduce their instability. A preliminary design of a linear quadratic regulator is presented as a solution to stabilize the system by using the solar sail only. Finally, invariant manifolds are exploited to identify orbits that present the opportunity of a ballistic transfer directly from low Earth orbit

    Effects of a hyperlipidic diet on experimental carcinogenesis of the breast: content and type of tumors

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    En el presente trabajo se han estudiado los efectos de una dieta hiperlipídica (20 % aceite de maíz) sobre las principales etapas de la carcinogénesis. Dicho estudio se ha realizado utilizando como soporte experimental el modelo del cáncer de mama inducido en la rata mediante dimetilbenz(a) antraceno. Los tumores mamarios malignos representan la patología más abundante aparecida en los animales. Tal resultado es atribuido específicamente a la acción del carcinógeno. Por otra parte, al comparar el número de tales tumores entre los diferentes grupos experimentales y el grupo control, se observa que la dieta hiperlipídica administrada tiene efectos promotores de la carcinogénesis mamaria en la rata. Este efecto no se obtiene si la dieta hiperlipídica se administra a los 157 días de la inducción carcinogénica. Además, los resultados obtenidos también indican que dicha dieta no tiene acción sobre la iniciación. Sin embargo, tal probabilidad no puede afirmarse dado que cabe la posibilidad de que la dieta hiperlipídica haya inducido cambios en los animales que hayan modificado la eficacia de la carcinogénesis
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