3,744 research outputs found

    Triaxial Angular Momentum Projection and Configuration Mixing calculations with the Gogny force

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    We present the first implementation in the (ÎČ,Îł)(\beta,\gamma) plane of the generator coordinate method with full triaxial angular momentum and particle number projected wave functions using the Gogny force. Technical details about the performance of the method and the convergence of the results both in the symmetry restoration and the configuration mixing parts are discussed in detail. We apply the method to the study of 24^{24}Mg, the calculated energies of excited states as well as the transition probabilities are compared to the available experimental data showing a good overall agreement. In addition, we present the RVAMPIR approach which provides a good description of the ground and gamma bands in the absence of strong mixing.Comment: 40 pages,14 figure

    Cosmological Bianchi Class A models in S\'aez-Ballester theory

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    We use the S\'aez-Ballester (SB) theory on anisotropic Bianchi Class A cosmological model, with barotropic fluid and cosmological constant, using the Hamilton or Hamilton-Jacobi approach. Contrary to claims in the specialized literature, it is shown that the S\'aez-Ballester theory cannot provide a realistic solution to the dark matter problem of Cosmology for the dust epoch, without a fine tunning because the contribution of the scalar field in this theory is equivalent to a stiff fluid (as can be seen from the energy--momentum tensor for the scalar field), that evolves in a different way as the dust component. To have similar contributions of the scalar component and the dust component implies that their past values were fine tunned. So, we reinterpreting this null result as an indication that dark matter plays a central role in the formation of structures and galaxy evolution, having measureable effects in the cosmic microwave bound radiation, and than this formalism yield to this epoch as primigenius results. We do the mention that this formalism was used recently in the so called K-essence theory applied to dark energy problem, in place to the dark matter problem. Also, we include a quantization procedure of the theory which can be simplified by reinterpreting the theory in the Einstein frame, where the scalar field can be interpreted as part of the matter content of the theory, and exact solutions to the Wheeler-DeWitt equation are found, employing the Bianchi Class A cosmological models.Comment: 24 pages; ISBN: 978-953-307-626-3, InTec

    Surface Electromyography of the Longissimus and Gluteus Medius Muscles in Greyhounds Walking and Trotting on Ground Flat, Up, and Downhill

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    In the field of canine rehabilitation, knowledge of muscle function in the therapeutic exercises prescribed is needed by physical therapists and veterinary surgeons. To gain insight into the function of longissimus dorsi (LD) and gluteus medius (GM) muscles in dogs, five Greyhounds performing leash walking and trotting on the ground flat, up (+7%), and downhill (−7%) were studied by surface electromyography, and the mean and maximum activity was compared. For the same incline, the surface electromyography (sEMG) of LD was higher (p < 0.05) at the trot than at the walk. In LD muscle, trotting uphill showed significantly higher maximum activity than any other exercise. A change of +7% incline or −7% decline affected (increased or decreased, respectively) the mean sEMG of the LD and GM muscles of dogs walking or trotting on the ground. When combined, the influence of gait and incline on electromyographic activity was analyzed, and walking at certain inclines showed no difference with trotting at certain inclines. Walking and trotting up and downhill added separate therapeutic value to flat motion. The results of the present study might contribute to a better understanding of the function of LD and GM muscles in dogs, this being especially useful for the field of canine rehabilitation

    Ejection of a Low Mass Star in a Young Stellar System in Taurus

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    We present the analysis of high angular resolution VLA radio observations, made at eleven epochs over the last 20 years, of the multiple system T Tauri. One of the sources (Sb) in the system has moved at moderate speed (5-10 km/s), on an apparently elliptical orbit during the first 15 years of observations, but after a close (< 2 AU) encounter with the source Sa, it appears to have accelerated westward to about 20 km/s in the last few years. Such a dramatic orbital change most probably indicates that Sb has just suffered an ejection - which would be the first such event ever detected. Whether Sb will ultimately stay on a highly elliptical bound orbit, or whether it will leave the system altogether will be known with about five more years of observations.Comment: 4 pages, accepter in ApJ Letter

    Influence of coach encouragement on technical demand of an small-sided games in football-7.

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    El objetivo del presente estudio ha sido analizar el efecto de la motivación del entrenador sobre la demanda técnica de un juego reducido (JR) 3 contra 3, realizado por futbolistas de categoría alevín, observando el nivel de aprendizaje técnico adquirido a través de estas tareas. Se han cuantificado el número de acciones técnicas que se producen en un JR de 3 contra 3 sin intervención del entrenador (JRSIE) y las que se producen en el mismo JR con la intervención del entrenador (JRCME). Se ha realizado en cada una de las 4 sesiones del programa de entrenamiento con JR dos test de valoración del dominio técnico en situaciones pre y post sesión. Los resultados confirman que aparecen diferencias en el número de acciones técnicas que el jugador realiza durante el JR, siendo significativamente mayor en el JRCME, generándose además mayor nivel de aprendizaje

    Large Scale Flows from Orion-South

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    Multiple optical outflows are known to exist in the vicinity of the active star formation region called Orion-South (Orion-S). We have mapped the velocity of low ionization features in the brightest part of the Orion Nebula, including Orion-S, and imaged the entire nebula with the Hubble Space Telescope. These new data, combined with recent high resolution radio maps of outflows from the Orion-S region, allow us to trace the origin of the optical outflows. It is confirmed that HH 625 arises from the blueshifted lobe of the CO outflow from 136-359 in Orion-S while it is likely that HH 507 arises from the blueshifted lobe of the SiO outflow from the nearby source 135-356. It is likely that redshifted lobes are deflected within the photon dominated region behind the optical nebula. This leads to a possible identification of a new large shock to the southwest from Orion-S as being driven by the redshifted CO outflow arising from 137-408. The distant object HH 400 is seen to have two even further components and these all are probably linked to either HH 203, HH 204, or HH 528. Distant shocks on the west side of the nebula may be related to HH 269. The sources of multiple bright blueshifted Herbig-Haro objects (HH 202, HH 203, HH 204, HH 269, HH 528) remain unidentified, in spite of earlier claimed identifications. Some of this lack of identification may arise from the fact that deflection in radial velocity can also produce a change in direction in the plane of the sky. The best way to resolve this open question is through improved tangential velocities of low ionization features arising where the outflows first break out into the ionized nebula.Comment: Astronomical Journal, in press. Some figures are shown at reduced resolution. A full-resolution version is available at http://ifront.org/wiki/Orion_South_Outflows_Pape

    Synthesis, characterization, bioactivity and biocompatibility of nanostructured materials based on the wollastonite-poly(ethylmethacrylate-co-vinylpyrrolidone) system

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    Composite materials are very promising biomaterials for hard tissue augmentation. The approach assayed in this work involves the manufacturing of a composite made of a bioactive ceramic, natural wollastonite (W) and a nanostructured copolymer of ethylmethacrylate (EMA) and vinylpyrrolidone (VP) to yield a bioresorbable and biocompatible VP–EMA copolymer. A bulk polymerization was induced thermally at 508C, using 1 wt % azobis(isobutyronitrile) (AIBN) as free-radical initiator. Structural characterization, compressive strength, flexural strength (FS), degradation, bioactivity, and biocompatibility were evaluated in specimens with a 60/40 VP/EMA ratio and ceramic content in the range 0–60%. A good integration between phases was achieved. Greater compression and FS, in comparison with the pure copolymer specimens was obtained only when the ceramic load got up to 60% of the total weight. The soaking in NaCl solution resulted in the initial swelling of the specimens tested. The maximum swelling was reached after 2–3 h of immersion and it was significantly greater for lower ceramic loads. This result makes the polymer component the main responsible for the interactions with the media. After soaking in SBF, microdomains segregation can be observed in the polymer component that can be related with a dramatic difference in the reactivity of both monomers in free radical polymerization, whereas the formation of an apatite-like layer on the W surfaces can be observed. Biocompatibility in vitro studies showed the absence of cytotoxicity of all formulations. The cells were able to adhere on the polystyrene negative control and on specimens containing 60 wt % wollastonite forming a monolayer and showing a normal morphology. However, a low cellular growth was observed. 2008 Wiley Periodicals, Inc. J Biomed Mater Res 88A: 53–64, 2009Peer reviewe

    Study of the influence of the operational parameters on the photoelectro-Fenton performance of an industrial wastewater treatment prototype using Orange II as a model pollutant

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    AbstractA two-stage photoelectro-Fenton reactor was built and employed to test its ability to remove colour using Orange II as a model dye compound. A set of four critical operational variables was defined for the reactor under study. In order to quantify their significance on colour removal, a 24 experimental factorial design was used. From the resultant data, and from a variable interaction analysis, a model of the reactor's performance as well as a characteristic set of experimental conditions was obtained. From this information, a triple interaction among current density, resin concentration and pH was statistically significant. Hydraulic retention time was not important. The best treatment among those studied was obtained at pH 3, current density 23.9 mA cm−2, and 3.7 g L−1 of resin concentration, with 96% decolorization. The best results with decolorization higher than 86% were obtained at acidic or slightly acidic pH, and higher levels of current density and resin concentration, or lower level of current density and resin concentration

    Understanding how organizational culture typology relates to organizational unlearning and innovation capabilities

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    This study focuses on the link between organizational unlearning and innovation capabilities and explores how this relationship might be managed within an innovative firm. In order to gain a clearer insight into to the influence of a firm’s culture on organizational unlearning and its innovation capabilities, a research model was developed that employs the Competing Values Framework (Cameron & Quinn, 1999). In this model, the influence of a firm’s cultural typology on unlearning and innovation is conceptualized and hypotheses are developed. The model was tested empirically using a sample of 145 firms drawn from the Spanish automotive components manufacturing sector and the relationships between the constructs were assessed using the partial least squares path-modeling approach. The results reveal that each distinct organizational culture exerts a different impact on the innovation and unlearning outcome variables. In particular, an adhocracy culture is associated closely with innovation capabilities while a market culture exerts a significant influence on organizational unlearnin
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