2,299 research outputs found

    On the performances of different nodal integration techniques and their stabilization

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    Finite element method was successfully applied in the simulation of several forming processes; however, it does not represent an absolute reference point. In fact, large deformation corresponds to a heavy mesh distortion. Powerful rezoning-remeshing algorithms strongly reduce the effects of such a limitation but the computational time significantly increases and additional errors occur. Nodal Integration is a recently introduced technique that allows finite element method to provide reliable results also when meshes becomes distorted in traditional FEMs. Furthermore, volumetric locking problems seem to be avoided using this integration technique instead of other methods such as coupled formulations. Nevertheless, spurious low-energy modes appear due to the nodal averaging of strain. For this reason stabilizing methods application seems to be suitable. What is more, different nodal integration techniques have been proposed, although spurious modes are a common problem. In this paper the performances of three different nodal integration techniques and the effects of a recently introduced stabilization methodology are studied simulating a classical forming process

    A new generation of real-time simulation techniques

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    This work presents a novel methodology for the development of real-time simulation techniques. They are focused on the PGD method, which allows the solution of complex problems by pre-calculating all the possible results. Subsequently, applications efficiently process these data to show particular results on demand

    Detection of the Ammonium Ion in Space

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    We report on the detection of a narrow feature at 262816.73 MHz towards Orion and the cold prestellar core B1-bS, that we attribute to the 1(0)-0(0) line of the deuterated Ammonium ion, NH3D+. The observations were performed with the IRAM 30m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved indicating a very low value for the electric quadrupolar coupling constant of Nitrogen which is expected for NH3D+ as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1(0)-0(0) transition of the Ammonium ion, 262817(6) MHz (3sigma), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is 1.1(0.2)e12 cm-2. Assuming a deuterium enhancement similar to that of NH2D, we derive N(NH4+) sim 2.6e13 cm-2, i.e., an abundance for Ammonium of a few 1e(-11).Comment: Accepted for publication in the Astrophysical Journal Letters 04 June 201

    A proper generalized decomposition approach for high-order problems

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    En este artículo se desarrollan dos aproximaciones distintas para la resolución de problemas de alto orden mediante métodos de descomposición propia generalizada (PGD, del inglés Proper Generalized Decomposition ). La primera está basada en el uso de técnicas de colocación y polinomios de Chebyshev, mientras que la segunda se basa en el uso de polinomios de Hermite en el marco de una formulación de Galerkin. Ambas poseen ventajas e inconvenientes, que se analizan en detalle con la ayuda de distintos problemas clásicos de validación.In this paper two different approximations for the solution of high-order problems by proper generalized decompositions (PGD) are developed. The first one is based upon the use of collocation techniques, along with Chebyshev polynomials, while the second employs Hermite polynomials in a Galerkin framework. Both approaches having pros and cons, they are studied with the help of some classical benchmark tests.Peer Reviewe

    In-plane/out-of-plane separated representations of updated Lagrangian descriptions of viscoplastic flow models in plate domains

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    A new efficient updated Lagrangian strategy for numerical simulations of material forming processes is presented. The basic ingredient is the tensorial decomposition of the velocity field into a finite sum of in-plane and an out-of-plane components, giving rise to an equivalent computational complexity of some two-dimensional problems and some one-dimensional ones (therefore, much less than the true three-dimensional complexity of the original problem). This is efficiently achieved by using Proper Generalized Decomposition (PGD) techniques, which are here employed in an updated Lagrangian framework for the very first time. This updated Lagrangian nature of the method needs the use of a robust numerical integration technique (in this case, the Stabilized Conforming Nodal Integration has been chosen) for addressing the highly distorted projected meshes. The resulting strategy is of general purpose, although it is especially well suited for addressing models defined in plate or shell (in general, parallelepipedic) domains. The basics of the just-developed method are shown, together with some numerical examples to show the potential of the technique

    Educación Deportiva versus Enseñanza Tradicional: Influencia sobre la regulación motivacional en alumnado de Bachillerato

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    El objetivo de esta investigación fue analizar el impacto de una intervención basada en el Modelo de Educación Deportiva (MED), en comparación con el Modelo de Enseñanza Tradicional (MET), sobre la regulación motivacional en alumnado de bachillerato en clase de Educación Física. Participó un total de 44 estudiantes (22 hombres y 22 mujeres, Medad = 16.32, DT = 0.57) de bachillerato. El diseño fue un estudio cuasi-experimental con medidas pre- y post-test y comparaciones intra- e inter-grupo. El programa de intervención consistió en 12 sesiones para la enseñanza del baloncesto, siguiéndose las directrices recomendadas por la literatura tanto para el grupo MED como para el grupo MET. Los resultados han indicado que el MED, respecto al MET, mejoró signicativamente el nivel de motivación intrínseca y de regulación identicada. Los hallazgos también han mostrado como el MED redujo signicativamente el nivel de regulación externa y desmotivación comparado con el MET. Como conclusión, el MED es un modelo de enseñanza deportiva que favorece el desarrollo de las regulaciones de motivación más autodeterminadas (motivación intrínseca y regulación identicada) en el proceso de enseñanza-aprendizaje en el contexto escolar, lo que podría suscitar el interés en el alumnado por la práctica deportiva de modo regular en el tiempo libre.

    Cannabinoid receptor CB2 ablation protects against TAU induced neurodegeneration.

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    Tauopathies are a group of neurodegenerative diseases characterized by the alteration/aggregation of TAU protein, for which there is still no effective treatment. Therefore, new pharmacological targets are being sought, such as elements of the endocannabinoid system (ECS). We analysed the occurrence of changes in the ECS in tauopathies and their implication in the pathogenesis. By integrating gene expression analysis, immunofluorescence, genetic and adeno-associated virus expressing TAU mouse models, we found a TAU-dependent increase in CB2 receptor expression in hippocampal neurons, that occurs as an early event in the pathology and was maintained until late stages. These changes were accompanied by alterations in the endocannabinoid metabolism. Remarkably, CB2 ablation in mice protects from neurodegeneration induced by hTAU P301L overexpression, corroborated at the level of cognitive behaviour, synaptic plasticity, and aggregates of insoluble TAU. At the level of neuroinflammation, the absence of CB2 did not produce significant changes in concordance with a possible neuronal location rather than its classic glial expression in these models. These findings were corroborated in post-mortem samples of patients with Alzheimer’s disease, the most common tauopathy. Our results show that neurons with accumulated TAU induce the expression of the CB2 receptor, which enhances neurodegeneration. These results are important for our understanding of disease mechanisms, providing a novel therapeutic strategy to be investigated in tauopathiespost-print8580 K

    Atypical carcinoid tumours of the lung: prognostic factors and patterns of recurrence

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    Background: Atypical carcinoids (AC) of the lung are rare intermediate-grade neuroendocrine neoplasms. Prognostic factors for these tumours are undefined. Methods: Our cooperative group retrieved data on 127 patients operated between 1980 and 2009 because of an AC. Several clinical and pathological features were studied. Results: In a univariable analysis, T-status (p=0.005), N-status (p=0.021), preoperative M-status (previously treated) (p=0.04), and distant recurrence developed during the outcome (p<0.001) presented statistically significant differences related to survival of these patients. In a multivariable analysis, only distant recurrence was demonstrated to be an independent risk factor for survival (p<0.001; HR: 13.1). During the monitoring, 25.2% of the patients presented some kind of recurrence. When we studied recurrence factors in a univariable manner, sublobar resections presented significant relationship with locoregional recurrence (p<0.001). In the case of distant recurrence, T and N status presented significant differences. Patients with preoperative M1 status presented higher frequencies of locoregional and distant recurrence (p=0.004 and p<0.001, respectively). In a multivariable analysis, sublobar resection was an independent prognostic factor to predict locoregional recurrence (p=0.002; HR: 18.1). Conclusions: Complete standard surgical resection with radical lymphadenectomy is essential for AC. Sublobar resections are related to locoregional recurrence, so they should be avoided except for carefully selected patients. Nodal status is an important prognostic factor to predict survival and recurrence. Distant recurrence is related to poor outcome

    Hormonal therapeutic strategy on the induction of accessory corpora lutea in relation to follicle size and on the increase of progesterone in sheep

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    We determined the effect of GnRH or hCG treatment on day 4 post-time artificial insemination (FTAI) on the formation of accessory corpora lutea (acc-CL) and on the concentration of serum progesterone (P4) in sheep. Multiparous adult Merino ewes (n = 36) were synchronized for estrus using double injection of PGF2a agonist (125 mg Cloprostenol) with an interval of 14 days. At 53e56 h after the second PG application, FTAI was performed. On day 4 post FTAI, ewes were either treated with analogue of GnRH (4 mg buserelin; n = 12) or hCG (300 IU, hCG; n = 12) or saline solution (1 ml; Control; n = 12). Two laparoscopic ovarian examinations were performed on days 4 and 10 post FTAI. In the first observation, we determined the number of post ovulation corpora lutea (po-CL) and the site, number and diameter of follicles present in both ovaries. In the second laparoscopy, we observed the number of po-CL and acc-CL. The sizes of the follicles that generated the acc-CL were determined according to the position of the follicles observed in the first laparoscopy. Serum P4 concentration was determined on days 4, 7, 10, 13, 17 and 21 post FTAI by chemiluminescence. A similar follicular population in size and number was observed in the three experimental groups prior to the beginning of treatments (Follicles 2 mm: 6.4 ± 3.7, 3 mm: 3.0 ± 2.3, 4 mm: 1.1 ± 0.5, 5 mm: 1.4 ± 0.8; P ˃ 0.05). The formation of 1.0 ± 0.4 and 1.1 ± 0.3 acc-CL was observed in the GnRH and hCG groups, respectively (P ˃ 0.05), but was not observed in the Control group (P &lt; 0.05). Follicle sizes from which acc-CL generated were 3, 4 and 5 mm and did not differ between hormonal treatments (P ˃ 0.05). The hCG group had higher mean concentrations of P4 on days 7, 10, 13 and 17 post FTAI compared with the GnRH group and the Control group (P &lt; 0.05), while no differences were observed between these two latter groups (P &gt; 0.05). Mean P4 concentrations in ewes treated with hCG showed no differences according to the size of the follicle from which acc-CL were generated (P ˃ 0.05). In conclusion, administration of hCG or GnRH on day 4 post FTAI induced the formation of one acc-CL from follicles of 3, 4 or 5 mm, indistinctly. However, serum P4 concentration increased significantly only in the hCG group. The serum P4 concentrations of acc-CL that originated from different follicle sizes did not differ.Facultad de Ciencias Veterinaria

    Belle II Technical Design Report

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    The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
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