103 research outputs found
Local bisection for conformal refinement of unstructured 4D simplicial meshes
We present a conformal bisection procedure for
local refinement of 4D unstructured simplicial meshes with
bounded minimum shape quality. Specifically, we propose a
recursive refine-to-conformity procedure in two stages, based on
marking bisection edges on different priority levels and defining
specific refinement templates. Two successive applications
of the first stage ensure that any 4D unstructured mesh can
be conformingly refined. In the second stage, the successive
refinements lead to a cycle in the number of generated similarity
classes and thus, we can ensure a bound over the minimum
shape quality. In the examples, we check that after successive
refinement the mesh quality does not degenerate. Moreover, we
refine a 4D unstructured mesh and a space-time mesh (3D + 1D)
representation of a moving object
Efectos de la edad relativa sobre la condición física aeróbica y el rendimiento en educación física en Secundaria
La intención de este estudio observacional consistió en identificar y comprobar la presencia de una problemática llamada Edad Relativa (ER) y su efecto (EER) en las aulas de Educación Física (EF) y el deporte en general. ER se refiere a la diferencia de edad cronológica entre los sujetos de un mismo grupo de edad. Por tanto, el EER son las consecuencias derivadas de la misma. Se observó el rendimiento físico a través de una prueba de resistencia aeróbica (Course Navette), el rendimiento en la asignatura de EF (calificaciones) y el abandono deportivo a través de un cuestionario escrito. Se constó con una muestra de 154 personas entre 15 y 17 años, comprendidos entre los cursos de 4º de ESO y 1º de Bachillerato, procedentes de un instituto de la provincia de Alicante. En el presente estudio se obtuvo unos porcentajes entre el 6,6% y el 19,2% en relación a los resultados de la Course Navette con la ER. Resultó un 4,5% y un 5,6% en la comparación de la prueba física hecha por género. En relación a las calificaciones en EF se observó que Q1>Q4, Q2>Q4 y Q3>Q4. Además, en cuanto al abandono deportivo se vio que Q2 y Q1 eran los porcentajes más altos de abandono, entre chicos y chicas respectivamente de 50% y 26,9%
Bisecting with optimal similarity bound on 3D unstructured conformal meshes
We propose a new method to mark for bisection the edges of an arbitrary 3D unstructured conformal mesh. For these meshes, the approach conformingly marks all the tetrahedra with coplanar edge marks. To this end, the method needs three key ingredients. First, we propose a specific edge ordering. Second, marking with this ordering, we guarantee that the mesh becomes conformingly marked. Third, we also ensure that all the marks are coplanar in each tetrahedron. To demonstrate the marking method, we implement an existent marked bisection approach. Using this implementation, we mark and then locally refine 3D unstructured conformal meshes. We conclude that the resulting marked bisection features an optimal bound of similarity classes per tetrahedron.This project has received funding from the European Research Council (ERC) under the European Union’sHorizon 2020 research and innovation programme under grant agreement No 715546. This work has also received funding from the Generalitat de Catalunya under grant number 2017 SGR 1731. The work of X. Roca has been partially supported by the Spanish Ministerio de Economía y Competitividad under the personal grant agreement RYC-2015-01633.Peer ReviewedPostprint (published version
Why continue sharing: determinants of behavior in collaborative economy services
La economía colaborativa está revolucionando la forma en que los consumidores utilizan los bienes y servicios. En nuestro estudio modificamos y ampliamos el modelo de confirmación de expectativas para determinar los factores motivacionales que impulsan la satisfacción y la intención de continuar usando los servicios de viajes colaborativos. Más importante aún, agregamos el valor social como un factor adicional. En este estudio fueron encuestados usuarios españoles experimentados de BlaBlaCar. La calidad del servicio, la utilidad percibida, la confianza y el valor social son determinantes de la satisfacción de los usuarios experimentados y, a través de ella, de la intención de continuar usando; mientras que no es el caso para el impacto ambiental ni para los beneficios económicos. Además, la confianza afecta directamente a la intención de continuar. Estos resultados tienen implicaciones gerenciales relevantes, mostrando que los usuarios de algunos servicios colaborativos están motivados por otros factores además de los económicos.The sharing economy is revolutionizing the way consumers use goods and services. In our study we modify and extend the expectation confirmation model to determine the motivational factors which drive the satisfaction and continue intention to use ridesharing services. Most importantly, we add social value as an additional factor to those previously studied in the literature. We apply our model in a survey among experienced Spanish users of BlaBlaCar. Service quality, perceived usefulness, trust and social value are determinants of satisfaction of experienced users and through it, of intention to continuance; while it is the case neither for environmental impact nor for economic benefits. Additionally, trust affects directly continuance. These results have relevant managerial implications, showing that users of some sharing services are motivated by other factors than purely economic
Local bisection for conformal refinement of unstructured 4D simplicial meshes
We present a conformal bisection procedure for local refinement of 4D unstructured simplicial meshes with bounded minimum shape quality. Specifically, we propose a recursive refine to conformity procedure in two stages, based on marking bisection edges on different priority levels and defining specific refinement templates. Two successive applications of the first stage ensure that any 4D unstructured mesh can be conformingly refined. In the second stage, the successive refinements lead to a cycle in the number of generated similarity classes and thus, we can ensure a bound over the minimum shape quality. In the examples, we check that after successive refinement the mesh quality does not degenerate. Moreover, we refine a 4D unstructured mesh and a space-time mesh (3D + 1D) representation of a moving object.This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 715546. This work has also received funding from the Generalitat de Catalunya under grant number 2017 SGR 1731. The work of X. Roca has been partially supported by the Spanish Ministerio de Economía y Competitividad under the personal grant agreement RYC-2015-01633.Peer ReviewedPostprint (author's final draft
Clasificación topoclimática de la sequía en la Península Ibérica de 1950 a 2007 a partir del SPI
Ponencia presentada en: VI Congreso Internacional de la Asociación Española de Climatología celebrado en Tarragona del 8 al 11 de octubre de 2008.[ES]Desde el punto de vista científico y social es interesante estudiar y clasificar los periodos de
sequía que han ocurrido en la Península Ibérica en los últimos 50 años para poder identificar
qué zonas tienen más susceptibilidad a padecer una escasez de agua. Mediante un estudio
orográfico y una clasificación sinóptica podemos clasificar la Península en distintas zonas
según la precipitación registrada en este periodo de tiempo y las situaciones meteorológicas
que predominan en cada una de las zonas. Así podemos intentar analizar cuáles pueden ser las
regiones con una tendencia más propensa a los periodos de sequía. Para establecer el criterio de
sequía utilizamos el Índice Estandarizado de Precipitación (SPI) que nos proporciona una
información directa y homogénea de la situación climática en cada momento. De esta forma
clasificamos la Península Ibérica dividiéndola en 9 zonas características a partir de las cuales
estudiamos la evolución del SPI utilizando el Índice para la escala temporal de 12 meses.
Analizando los gráficos de la evolución anual del SPI localizamos y comprobamos episodios
de sequía ocurridos a lo largo de nuestro periodo de estudio.[EN]From the scientific and social point of view it is interesting to study and to classify the
drought's episode that the Iberian Peninsula has had in the last 50 years with this idea we are
able to identify which areas are more susceptible to suffer a water shortage. By means of an
orographical and synoptic study we can classify the Peninsula under different zones according
to the rainfall registered in this period and the meteorological synoptic patterns in each of the
zones. This way we can try to analyze which can be the regions with a high tendency to the
periods of drought. To establish the criterion of drought we use the Standardized Precipitation
Index (SPI) that provides us a direct and homogeneous information of the climatological
situation in every moment. In this way we classify the Iberian Peninsula divided into 9 typical
zones from which we study the evolution of the SPI using the Index for the time scale of 12
months. Analyzing the graphs of the annual evolution of the SPI we locate and verify episodes
of drought happened along our period of study.Este trabajo está realizado dentro del proyecto CICYT: "DULCINEA. Desarrollo de
Metodologías para caracterizar las cubiertas vegetales a partir de sensores de última
generación. Cambio Climático y su incidencia en la vegetación de la Península Ibérica". Ref.
CGL2005-0420
Regionalización de la sequía en la Península Ibérica desde 1950 hasta 2007 a partir del SPI y una modelización digital terreno
Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008.Este trabajo está realizado dentro del proyecto CICYT: “DULCINEA. Desarrollo de Metodologías para caracterizar las cubiertas vegetales a partir de sensores de última generación. Cambio Climático y
su incidencia en la vegetación de la Península Ibérica”. Ref. CGL2005-04202
Perioperative goal-directed hemodynamic therapy based on radial arterial pulse pressure variation and continuous cardiac index trending reduces postoperative complications after major abdominal surgery: a multi-center, prospective, randomized study
IntroductionSeveral single-center studies and meta-analyses have shown that perioperative goal-directed therapy may significantly improve outcomes in general surgical patients. We hypothesized that using a treatment algorithm based on pulse pressure variation, cardiac index trending by radial artery pulse contour analysis, and mean arterial pressure in a study group (SG), would result in reduced complications, reduced length of hospital stay and quicker return of bowel movement postoperatively in abdominal surgical patients, when compared to a control group (CG).Methods160 patients undergoing elective major abdominal surgery were randomized to the SG (79 patients) or to the CG (81 patients). In the SG hemodynamic therapy was guided by pulse pressure variation, cardiac index trending and mean arterial pressure. In the CG hemodynamic therapy was performed at the discretion of the treating anesthesiologist. Outcome data were recorded up to 28 days postoperatively.ResultsThe total number of complications was significantly lower in the SG (72 vs. 52 complications, p = 0.038). In particular, infection complications were significantly reduced (SG: 13 vs. CG: 26 complications, p = 0.023). There were no significant differences between the two groups for return of bowel movement (SG: 3 vs. CG: 2 days postoperatively, p = 0.316), duration of post anesthesia care unit stay (SG: 180 vs. CG: 180 minutes, p = 0.516) or length of hospital stay (SG: 11 vs. CG: 10 days, p = 0.929).ConclusionsThis multi-center study demonstrates that hemodynamic goal-directed therapy using pulse pressure variation, cardiac index trending and mean arterial pressure as the key parameters leads to a decrease in postoperative complications in patients undergoing major abdominal surgery.Trial registrationClinicalTrial.gov, NCT01401283
Intraoperative PaO2 is not related to the development of surgical site infections after major cardiac surgery
Producción CientíficaBackground: The perioperative use of high inspired oxygen fraction (FIO2) for preventing surgical site infections (SSIs) has demonstrated a reduction in their incidence in some types of surgery however there exist some discrepancies in this respect. The aim of this study was to analyze the relationship between PaO2 values and SSIs in cardiac patients. Methods: We designed a prospective study in which 1,024 patients undergoing cardiac surgery were analyzed. Results: SSIs were observed in 5.3% of patients. There was not significant difference in mortality at 30 days between patients with and without SSIs. In the uni and multivariate analysis no differences in function of the inspired oxygen fraction administrated were observed. Conclusions: We observed that the PaO2 in adult cardiac surgery patients was not related to SSI rate
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