993 resultados para Interphase Boundary Structure
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The purpose of this article is to introduce a Cartesian product structure into the social choice theoretical framework and to examine if new possibility results to Gibbard's and Sen's paradoxes can be developed thanks to it. We believe that a Cartesian product structure is a pertinent way to describe individual rights in the social choice theory since it discriminates the personal features comprised in each social state. First we define some conceptual and formal tools related to the Cartesian product structure. We then apply these notions to Gibbard's paradox and to Sen's impossibility of a Paretian liberal. Finally we compare the advantages of our approach to other solutions proposed in the literature for both impossibility theorems.
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In this paper, a new class of generalized backward doubly stochastic differential equations is investigated. This class involves an integral with respect to an adapted continuous increasing process. A probabilistic representation for viscosity solutions of semi-linear stochastic partial differential equations with a Neumann boundary condition is given.
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The metropolitan spatial structure displays various patterns, sometimes monocentricity and sometimes multicentricity, which seems much more complicated than the exponential density function used in classic works such as Clark (1961), Muth (1969) or Mills (1973) among others, can effectively represent. It seems that a more flexible density function,such as cubic spline function (Anderson (1982), Zheng (1991), etc.) to describe the density-accessibility relationship is needed. Also, accessibility, the fundamental determinant of density variations, is only partly captured by the inclusion of distance to the city centre as an explanatory variable. Steen (1986) has proposed to correct that miss-especification by including an additional gradient for distance to the nearest transportation axis. In identifying the determinants of urban spatial structure in the context of inter-urban systems, some of the variables proposed by Muth (1969), Mills (1973) and Alperovich (1983) such as city age or population, make no sense in the case of a single urban system. All three criticism to the exponential density function and its determinants apply for the Barcelona Metropolitan Region, a polycentric conurbation structured on well defined transportation axes.
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This paper characterizes the equilibria in airline networks and their welfare implications in an unregulated environment. Competing airlines may adopt either fully-connected (FC) or hub-and-spoke (HS) network structures; and passengers exhibiting low brand loyalty to their preferred carrier choose an outside option to travel so that markets are partially served by airlines. In this context, carriers adopt hubbing strategies when costs are sufficiently low, and asymmetric equilibria where one carrier chooses a FC strategy and the other chooses a HS strategy may arise. Quite interestingly, flight frequency can become excessive under HS network configurations.
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This paper investigates experimentally how organisational decision processes affect the moral motivations of actors inside a firm that must forego profits to reduce harming a third party. In a "vertical" treatment, one insider unilaterally sets the harm-reduction strategy; the other can only accept or quit. In a "horizontal" treatment, the insiders decide by consensus. Our 2-by-2 design also controls for communication effects. In our data, communication makes vertical firms more ethical; voice appears to mitigate "responsibility-alleviation" in that subordinates with voice feel responsible for what their firms do. Vertical firms are then more ethical than the horizontal firms for which our bargaining data reveal a dynamic form of responsibility-alleviation and our chat data indicate a strong "insider-outsider" effect.
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Let M be a compact hyperbolic 3-manifold with incompressible boundary. Consider a complete hyperbolic metric on int(M). To each geometrically finite end of int(M) are traditionnaly associated 3 different invariants : the hyperbolic metric associated to the conformal structure at infinity, the hyperbolic metric on the boundary of the convex core and the bending measured lamination of the convex core. In this note we show how invariants of different types can be realised in the different ends.
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Boundary equilibrium bifurcations in piecewise smooth discontinuous systems are characterized by the collision of an equilibrium point with the discontinuity surface. Generically, these bifurcations are of codimension one, but there are scenarios where the phenomenon can be of higher codimension. Here, the possible collision of a non-hyperbolic equilibrium with the boundary in a two-parameter framework and the nonlinear phenomena associated with such collision are considered. By dealing with planar discontinuous (Filippov) systems, some of such phenomena are pointed out through specific representative cases. A methodology for obtaining the corresponding bi-parametric bifurcation sets is developed.
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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.
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We analyse the implications of optimal taxation for the stochastic behaviour of debt. We show that when a government pursues an optimal fiscal policy under complete markets, the value of debt has the same or less persistence than other variables in the economy and it declines in response to shocks that cause the deficit to increase. By contrast, under incomplete markets debt shows more persistence than other variables and it increases in response to shocks that cause a higher deficit. Data for US government debt reveals diametrically opposite results from those of complete markets and is much more supportive of bond market incompleteness.
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The alpha1b-adrenergic receptor (AR) is a member of the large superfamily of seven transmembrane domain (TMD) G protein-coupled receptors (GPCR). Combining site-directed mutagenesis of the alpha1b-AR with computational simulations of receptor dynamics, we have explored the conformational changes underlying the process of receptor activation, i.e. the transition between the inactive and active states. Our findings suggest that the structural constraint stabilizing the alpha1b-AR in the inactive form is a network of H-bonding interactions amongst conserved residues forming a polar pocket and R143 of the DRY sequence at the end of TMDIII. We have recently reported that point mutations of D142, of the DRY sequence and of A293 in the distal portion of the third intracellular loop resulted in ligand-independent (constitutive) activation of the alpha1b-AR. These constitutively activating mutations could induce perturbations resulting in the shift of R143 out of the polar pocket. The main role of R143 may be to mediate receptor activation by triggering the exposure of several basic amino acids of the intracellular loops towards the G protein. Our investigation has been extended also to the biochemical events involved in the desensitization process of alpha1b-AR. Our results indicate that immediately following agonist-induced activation, the alpha1b-AR can undergo rapid agonist-induced phosphorylation and desensitization. Different members of the G protein coupled receptor kinase family can play a role in agonist-induced regulation of the alpha1b-AR. In addition, constitutively active alpha1b-AR mutants display different phosphorylation and internalization features. The future goal is to further elucidate the molecular mechanism underlying the complex equilibrium between activation and inactivation of the alpha1b-AR and its regulation by pharmacological substances. These findings can help to elucidate the mechanism of action of various agents displaying properties of agonists or inverse agonists at the adrenergic system.