1,277 research outputs found

    Classroom communication skills: the need to fill a gap in the training of teachers of Spanish as a foreign language

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    This paper sets out the necessity of examining the communication skills of teachers of Spanish as a foreign language as conducted in other socio-educative contexts. According to this objective, the paper begins with a review of theoretical efforts that have been made during recent years referring to research methodology (such as instruments), and to their main results. This leads to a discussion of the training needs that teachers of Spanish as a foreign language presently face for the development of their communication s kills in the classroom and, in general terms, the paper discusses the different types of ideas and strategies that must be considered during teachers’ instruction. Finally, this brief proposal expects to be the seed of future research projects that impact positively on the improvement of teachers’ communication competence, whereby the ideas discussed here are taken as a nuclear component in the frame of future teaching competence

    Influence of hydrogen peroxide in the tribocorrosion behaviour of a CoCrMo biomedical alloy

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    This paper studies the influence of hydrogen peroxide (H2O2) in simulated body fluids on the wear and corrosion behaviour of a CoCrMo biomedical alloy. CoCrMo are passive materials commonly used in prosthesis and implants because of its high corrosion resistance and mechanical properties. Hydrogen peroxide is produced by bacteria and leukocytes as a consequence of an inflammatory reaction which may modify the tribo-electrochemical response of metals implanted in the human body. Indeed, the oxidizing environment generated by the presence of the peroxide increases the metal dissolution rate. Electrochemical and tribocorrosion tests were carried out in a PBS solution with different addition of H2O2 (0.5, 2, 4 and 12%).The authors acknowledge Generalitat Valencia for the Gerónimo Forteza financial support and to the Electron Microscopy Service of the UPV for the SEM images

    Moduli spaces for finite-order jets of Riemannian metrics

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    We construct the moduli space of r-jets at a point of Riemannian metrics on a smooth manifold. The construction is closely related to the problem of classification of jet metrics via differential invariants. The moduli space is proved to be a differentiable space which admits a finite canonical stratification into smooth manifolds. A complete study on the stratification of moduli spaces is carried out for metrics in dimension n=2.Comment: 25 pages, corrected typos, partially changed content with an appendix adde

    CPU and GPU oriented optimizations for LiDAR data processing

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    Digital Terrain Models (DTM) can be accurately obtained from clouds of LiDAR points but the corresponding cloud processing time can be prohibitive. This paper describes several optimization techniques that have been applied to the Overlap Window Method (OWM) that is a key component in DTM applications. OWM was originally implemented in R which translates into serious limitations in terms of the size of the LiDAR point cloud that can be processed. We have ported the code to C++, significantly optimized the data structure to minimize memory accesses, and developed parallel implementations for CPU and GPU commodity devices using oneAPI libraries and tools. This results in CPU and GPU versions that are up to 19x and 83x faster, respectively, than an OpenMP baseline that uses eight CPU cores. Most importantly, the proposed optimizations for CPU and GPU can be paramount to get the most out of other LiDAR-based algorithms in which the careful selection of the right data structure, parallelization strategies and memory access reduction techniques will certainly result in significant performance improvements.Funding for open access charge: Universidad de Málag / CBU

    Effect of band-filling and structural distortions on the Curie temperature of Fe-Mo double perovkites

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    By means of high resolution neutron powder diffraction at low temperature we have characterized the structural details of LaxSr2xFeMoO6\rm La_{x}Sr_{2-x}FeMoO_6 (0x0.50\leq {\rm x}\leq 0.5) and CaxSr2xFeMoO6\rm Ca_{x}Sr_{2-x}FeMoO_6 (0x0.60\leq {\rm x}\leq 0.6) series of compounds. This study reveals a similar variation of the mean bond-angle \FeOMo in both series. In contrast, the mean bond-distance \FeMoO\ increases with La but not with Ca substitution. Both series also present a different evolution of the Curie temperature (TCT_C), which raises in the La series and slightly decreases in the Ca one. We thus conclude that the enhancement of TCT_C in the La series is due to the electron filling of the conduction band and a concomitant rising of the density of states at the Fermi level.Comment: Revtex, 4 Journal pages, 2 figures, 1 tabl

    Rotura de cotilo en artroplastia total de cadera

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    Describimos dos casos de rotura de cotilos de expansión de prótesis de cadera tipo CLS de origen no traumático. Ambos casos sucedieron a los seis años de cirugía y no se apreció desgaste o rotura del polietileno en ninguno de ellos. En nuestra opinión la hipótesis más probable es que la falta de contacto entre la zona polar del cotilo y el fondo del acetábulo produzca una zona de inestabilidad en los segmentos de la prótesis y rotura por fatiga del material. Creemos que es obligado su recambio aunque el paciente no presente sintomatología actual, ya que la rotura del acetábulo conducirá a un aflojamiento y a una osteolisis secundaria.We describe two cases of breakage of expansion cups in a CLS uncemented total hip arthroplasty wihtout traumatic etiologic. Both cases occurred six years after the surgery and none had breakage or polyethylene wear. We postulate that the lack of contact between the polar area of the cup and the acetabulum produces a zone of instability in the segments of the prosthesis and increases the risk of fatigue of the material. In our opinion acetabular revision is mandatory in this situation, even in asymptomatic cases, because cup rupture leads to implant loosening with secondary short-team osteolysis

    Evidencias del incremento en la movilidad de dunas costeras en el último medio siglo como respuesta a la intervención humana

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    Given the risk of two roads being buried by the sand of two highly mobile coastal dunes (Valdevaqueros and Bolonia, SW Spain), several measures have been taken over the last half century in order to stabilize them or at least slow their progress: installation of several rows of 1-m-high concrete structures, planting of species such as Pinus pinea, Retama monosperma and Ammophila arenaria, wicker and wooden fencing, and sand mining (only performed on the Valdevaqueros dunefield). The evolution of the two dunes was investigated through the interpretation of intensive topographical monitoring and aerial photography. Average migration rates of approximately 10 m yr–1 were detected and the burial of anthropic structures has eventually occurred. This process has caused a serious regional problem, making dune management of these areas a difficult challenge. The comparison of the evolution of these two dunes has been of great importance in assessing the effect of historical human intervention and has provided a new perspective for future dune management strategies. The results obtained show that management measures based on sand removal have been proven to be unsustainable. Moreover, the monitoring methodology presented herein has proven very useful in predicting dune advance rates. For instance, the Bolonia dune could reach the nearest road in approximately 12 years.Se han tomado diferentes medidas a lo largo del último medio siglo tratando de estabilizar o al menos ralentizar el progreso de dos dunas costeras de alta movilidad (Valdevaqueros y Bolonia, SW España) dado el riesgo de enterramiento de sendas carreteras: Entre las medidas tomadas cabe destacar la instalación de filas de estructuras de hormigón de 1 m de altura, la plantación de diferentes especies (como el Pinus pinea, la Retama monosperma o la Ammophila arenaria), vallas de madera y brezo, y la extracción de arena (sólo en la duna de Valdevaqueros). La evolución de ambas dunas se ha investigado a través de la comparación de levantamientos topográficos y fotografías aéreas. Se han detectado tasas medias de avance de aproximadamente 10 m/año hasta que, finalmente, se han enterrado estructuras antrópicas. Este proceso ha causado graves problemas convirtiendo en un difícil reto la gestión de dunas de estas áreas. La comparación de la evolución de estas dos dunas ha resultado de gran importancia a la hora de evaluar el efecto de la intervención humana, y ha proporcionado una nueva perspectiva para las futuras estrategias de gestión. Entre los resultados obtenidos, debería destacarse el que la gestión basada en la retirada de arena ha resultado insostenible. Además, la metodología de seguimiento aquí presentada ha probado ser de gran utilidad al predecir las tasas de avance de las dunas. Por ejemplo, la duna de Bolonia podría alcanzar la carretera próxima en unos 12 años

    Evidence of coastal dune mobility increases over the last half century in response to historical human intervention

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    Given the risk of two roads being buried by the sand of two highly mobile coastal dunes (Valdevaqueros and Bolonia, SW Spain), several measures have been taken over the last half century in order to stabilize them or at least slow their progress: installation of several rows of 1-m-high concrete structures, planting of species such as Pinus pinea, Retama monosperma and Ammophila arenaria, wicker and wooden fencing, and sand mining (only performed on the Valdevaqueros dunefield). The evolution of the two dunes was investigated through the interpretation of intensive topographical monitoring and aerial photography. Average migration rates of approximately 10 m yr–1 were detected and the burial of anthropic structures has eventually occurred. This process has caused a serious regional problem, making dune management of these areas a difficult challenge. The comparison of the evolution of these two dunes has been of great importance in assessing the effect of historical human intervention and has provided a new perspective for future dune management strategies. The results obtained show that management measures based on sand removal have been proven to be unsustainable. Moreover, the monitoring methodology presented herein has proven very useful in predicting dune advance rates. For instance, the Bolonia dune could reach the nearest road in approximately 12 years

    Forest management scenarios drive future dynamics of Mediterranean planted pine forests under climate change

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    Context: Planted pine forests are highly abundant communities in the Mediterranean Basin. Being the result of past reforestation, these forests show high species and structural homogeneity. Diversification to conifer-broadleaved mixed forests is recommended to promote adaptation to climate change and increase their resilience to perturbations. Objectives: This study aims at evaluating how these planted pine forests will develop in the future as a result of the combined impacts of management and climate. Methods: We applied a forest landscape model (LANDIS-II) to simulate different climate scenarios and management strategies designed in cooperation with forest managers to assess their effects on the performance of planted pine forests and their change in terms of forest composition. Results: Climate change scenarios caused a shift in the phenological growth pattern of planted pine forests by reducing forest growth during summer and increasing photosynthetic productivity in spring and fall, particularly under high emission scenarios. Biomass increased through time and more strongly under climate change, but this increase differs among species, resulting in changes of forest types across the landscape. Our results portray natural succession as the main driver of forest change, but intensive management accelerated this process by limiting pine growth and promoting growth of oak species. Conclusions: Our results highlight the importance of active management on planted pine forests to favour mixed and climate-adapted ecosystems in shorter time scales than offered by succession alone. Moreover, our spatially explicit modelling approach helps to identify areas where lack of seed dispersal and/or competitive exclusion prevent natural diversification, providing useful recommendations for interventions. However, the modelling approach has some limitations since it does not consider natural disturbances
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