26 resultados para shifting boundaries

em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A renewed interest on the use of tolls for funding motorways and regulating their demands has been recovered in the last years. However, less attention has been put to the road safety effects derived from this policy. Although toll motorways show quality levels equal or above free motorways, charging users for the use of better infrastructure shifts some traffic to their low quality adjacent alternatives. In the present study we test whether charging for the use of the better road might negatively affect road safety in the worst adjacent road. The results confirm our hypothesis opening a new concern.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present a study of the evaporation dynamics of a substance undergoing a coarsening process. The system is modeled by the Cahn-Hilliard equation with absorbing boundaries. We have found that the dynamics, although of a diffusive nature, is much slower than the usual one without coarsening. Analytical and simulation results are in reasonable agreement.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We investigate the depinning transition occurring in dislocation assemblies. In particular, we consider the cases of regularly spaced pileups and low-angle grain boundaries interacting with a disordered stress landscape provided by solute atoms, or by other immobile dislocations present in nonactive slip systems. Using linear elasticity, we compute the stress originated by small deformations of these assemblies and the corresponding energy cost in two and three dimensions. Contrary to the case of isolated dislocation lines, which are usually approximated as elastic strings with an effective line tension, the deformations of a dislocation assembly cannot be described by local elastic interactions with a constant tension or stiffness. A nonlocal elastic kernel results as a consequence of long-range interactions between dislocations. In light of this result, we revise statistical depinning theories of dislocation assemblies and compare the theoretical results with numerical simulations and experimental data.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We explore the statistical properties of grain boundaries in the vortex polycrystalline phase of type-II superconductors. Treating grain boundaries as arrays of dislocations interacting through linear elasticity, we show that self-interaction of a deformed grain boundary is equivalent to a nonlocal long-range surface tension. This affects the pinning properties of grain boundaries, which are found to be less rough than isolated dislocations. The presence of grain boundaries has an important effect on the transport properties of type-II superconductors as we show by numerical simulations: our results indicate that the critical current is higher for a vortex polycrystal than for a regular vortex lattice. Finally, we discuss the possible role of grain boundaries in vortex lattice melting. Through a phenomenological theory we show that melting can be preceded by an intermediate polycrystalline phase.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present a study of the evaporation dynamics of a substance undergoing a coarsening process. The system is modeled by the Cahn-Hilliard equation with absorbing boundaries. We have found that the dynamics, although of a diffusive nature, is much slower than the usual one without coarsening. Analytical and simulation results are in reasonable agreement.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Workgroup diversity can be conceptualized as variety, separation, or disparity. Thus, the proper operationalization of diversity depends on how a diversity dimension has been defined. Analytically, the minimal diversity must be obtained when there are no differences on an attribute among the members of a group, however maximal diversity has a different shape for each conceptualization of diversity. Previous work on diversity indexes indicated maximum values for variety (e.g., Blau"s index and Teachman"s index), separation (e.g., standard deviation and mean Euclidean distance), and disparity (e.g., coefficient of variation and the Gini coefficient of concentration), although these maximum values are not valid for all group characteristics (i.e., group size and group size parity) and attribute scales (i.e., number of categories). We demonstrate analytically appropriate upper boundaries for conditional diversity determined by some specific group characteristics, avoiding the bias related to absolute diversity. This will allow applied researchers to make better interpretations regarding the relationship between group diversity and group outcomes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The chapters collected in this volume are only a small sampling of the fruitwhich carne out ofthe Evil, Women and the Feminine conference held in Prague inMay 2010, hosted by the Inter-Disciplinary.Net. Our hopes are to bring togethersorne of the chapters, in expanded form, which seemed, without previous planning,to speak to each other during the conference and which, herein, more directiyengage with one another, opening up a space for dialogue and interaction. Whilewe have divided the work into four sections, they are not discrete boundaries but, we hope, they work together to elicit an interdisciplinary approach to ourunderstandings of women who push the limits of 'the feminine.'

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The chapters collected in this volume are only a small sampling of the fruitwhich carne out ofthe Evil, Women and the Feminine conference held in Prague inMay 2010, hosted by the Inter-Disciplinary.Net. Our hopes are to bring togethersorne of the chapters, in expanded form, which seemed, without previous planning,to speak to each other during the conference and which, herein, more directiyengage with one another, opening up a space for dialogue and interaction. Whilewe have divided the work into four sections, they are not discrete boundaries but, we hope, they work together to elicit an interdisciplinary approach to ourunderstandings of women who push the limits of 'the feminine.'

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper, some steganalytic techniques designed to detect the existence of hidden messages using histogram shifting methods are presented. Firstly, some techniques to identify specific methods of histogram shifting, based on visible marks on the histogram or abnormal statistical distributions are suggested. Then, we present a general technique capable of detecting all histogram shifting techniques analyzed. This technique is based on the effect of histogram shifting methods on the "volatility" of the histogram of differences and the study of its reduction whenever new data are hidden.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Inhibition of cholesterol export from late endosomes causes cellular cholesterol imbalance, including cholesterol depletion in the trans-Golgi network (TGN). Here, using Chinese hamster ovary (CHO) Niemann-Pick type C1 (NPC1) mutant cell lines and human NPC1 mutant fibroblasts, we show that altered cholesterol levels at the TGN/endosome boundaries trigger Syntaxin 6 (Stx6) accumulation into VAMP3, transferrin, and Rab11-positive recycling endosomes (REs). This increases Stx6/VAMP3 interaction and interferes with the recycling of αVβ3 and α5β1 integrins and cell migration, possibly in a Stx6-dependent manner. In NPC1 mutant cells, restoration of cholesterol levels in the TGN, but not inhibition of VAMP3, restores the steady-state localization of Stx6 in the TGN. Furthermore, elevation of RE cholesterol is associated with increased amounts of Stx6 in RE. Hence, the fine-tuning of cholesterol levels at the TGN-RE boundaries together with a subset of cholesterol-sensitive SNARE proteins may play a regulatory role in cell migration and invasion.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of a tantalum wire in hot-wire chemical vapour deposition (HWCVD) has allowed the deposition of dense nanocrystalline silicon at low filament temperatures (1550 °C). A transition in the crystalline preferential orientation from (2 2 0) to (1 1 1) was observed around 1700 °C. Transmission electron microscopy (TEM) images, together with secondary ion mass spectrometry (SIMS) measurements, suggested that no oxidation occurred in materials obtained at low filament temperature due to the high density of the tissue surrounding grain boundaries. A greater concentration of SiH 3 radicals formed at these temperatures seemed to be responsible for the higher density.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En el marco del proyecto “La ciutat romana de Cosa: arqueologia d’un enclau comercial mediterrani” , autorizado y apoyado por la Soprintendenza Archeologica por la Toscana, entre los dias 4 y 22 de septiembre de 2006 se ha realizado la segunda campaña de intervenciones arqueológicas en la ciudad romana de Cosa (Ansedonia, prov. Grosseto, Itàlia), colonia latina fundada en el 273 aC a unos 120 km. al norte de Roma. De acuerdo a los resultados obtenidos en la campanya del 2005 (localización/verificación de los límites precisos de la ínsula O-P/4-5 mediante la aplicación de técnicas de prospección geofísica completadas con la limpieza, registro y documentación arqueológica de las estructuras localizadas ) los trabajos del 2006 se han orientado hacia la identificación de la organización interna de la dicha ínsula tomando como referente el criptopórtico situado en el extremo N.E., el cual parece constituir el límite de una estructura singular (privada o pública ) estratégicamente ubicada en relación al fórum i a la Via Sacra. El trabajo de campo ha consistido en un intenso decapage con la finalidad de delimitar unidades de habitación complejas funcionalmente definidas y así la articulación existente entre ellas; en este sentido se ha podido documentar evidencias del espacio porticado superpuesto al criptopórtico así como, paralelamente a la calle 5 y en dirección a la Via Sacra, parte de habitaciones algunas de las cuales conservaban restos del pavimiento original, en un caso de mosaico. Paralelamente, se ha realizado el análisis en laboratorio de los materiales recuperados los cuales, aún procediendo de nivel superficial, empiezan a proporcionar datos sobre los diferentes momentos de ocupación de la zona, básicamente tardorepublicanos y augustales.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Resumen. Los avellanos en Asturias se encuentran en los cauces de los ríos, delimitando fincas o aislados. Son escasas las plantaciones regulares de esta especie. Durante tres años (2003-04-05) se realizó una prospección conjunta entre el IRTA y el SERIDA, con el fin de estudiar el material asturiano e intentar conservar el material genético en período de extinción. Se preseleccionaron 90 individuos atendiendo a sus características vegetativas y del fruto. Se ha observado una gran variabilidad genética del avellano en esta zona norte de España y en un primer estudio se han encontrado 16 individuos interesantes por sus buenas características del fruto. En Febrero de 2008, ya se ha empezado a introducir material en colección (en el IRTA y en el SERIDA), con el fin de conservar el material y realizar, posteriormente, su caracterización agronómica y comercial Abstract. Asturias region is known for its wild hazelnuts growing spontaneously or planted on land boundaries and on river banks. There are few orchards of this species. During three years (2003-04-05), a survey of native hazelnuts started in collaboration IRTA and SERIDA, to study this material and preserve the genetic diversity. In this prospection a total of 90 trees were studied and a high genetic variability was observed, outstanding 16 individuals for their good fruit characteristics. In February, 2008, preselected material has been introduced at two collections (IRTA and SERIDA) for his preservation and agronomic and commercial characterisation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Report for the scientific sojourn carried out at the Departament de Psicologia de la Universitat de les Illes Balears, Spain, from May until July 2006. Abnormalities in executive functions, including set shifting ability, represent a cardinal feature in schizophrenia. This ability to adapt behavior to changing environmental events or contingencies requires a mechanism for switching attention between learned stimulus-response associations, or task-sets. This project aimed at gaining further knowledge on the brain mechanisms related to the executive control of attention in schizophrenia during the performace of a task switching paradigm. Furthermore, a secondary goal was to further examine the interrelationships between endogenous and exogenous control processes in task set switching.