Fast growth at low temperature in vacancy-mediated phase-separation

We study the phase-separation dynamics of a two-dimensional Ising model where A and B particles can only exchange position with a vacancy. In a wide range of temperatures the kinetics is dominated, during a long preasymptotic regime, by diffusion processes of particles along domain interfaces. The dynamical exponent z associated to this mechanism differs from the one usually expected for Kawasaki dynamics and is shown to assume different values depending on temperature and relative AB concentration. At low temperatures, in particular, domains grow as t^{1/2}, for equal AB volume fractions.Comment: LaTeX, 5 pages, 4 figures, to appear on Phys. Rev.

Representación y causalidad en las discusiones actuales sobre cognición: el caso "Watt Governor"

Recently, the cognitive sciences have been involved in a debate between Representationalists and anti-Representationalists as to the representational status of the Watt governor. Tim van Gelder has argued that the Watt governor is a paradigmatic example of an intelligent system, which is not in need of internal representations to carry out its cognitive activity. In response, William Bechtel has argued that, given the ?stand-in? definition of representation, such artifact should be interpreted as representing. My aim in this paper is to give a negative answer to the question. To support this I will argue that it is essential for the representations to be normative, which means that they are only attributable to those who/which have the capacity to correct their behavior. Being so, the governor should not be located within the set of representational systems, because it is not possible to find in its behaviors signs of this normative capacity.Fil: Castellano, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Humanidades. Universidad Nacional de Córdoba. Instituto de Humanidades; Argentin

New firm performance and territorial driving forces.

We study post entry performance of manufactuirng firms in 3 municipalities of Buenos Aires province, borned between 1990 and 1999. The aim of the paper is to identify main factors explaining firm growth. The focus is directed to endogenous determinants of firm performance, individual or local as well, taking into account the growing interest those elements are receiving in recent literature about local development. The results show that firm tradability grade is the key variable explaining performance. This factor is strongly influenced by entrepreneur´s profile but also by macroeconomic context.local development, new firms, firm performance, tradability

Non-conceptualism, observational concepts, and the given

In “Study of Concepts”, Peacocke puts forward an argument for non-conceptualism derived from the possession conditions of observational concepts. In this paper, I raise two objections to this argument. First, I argue that if non-conceptual perceptual contents are scenario contents, then perceptual experiences cannot present perceivers with the circumstances specified by the application conditions of observational concepts and, therefore, they cannot play the semantic and epistemic roles Peacocke wants them to play in the possession conditions of these concepts. Second, I argue that if non-conceptual perceptual contents are protopropositions, then Peacocke’s account of the possession conditions of observational concepts falls into the Myth of the Given.; En “Study of Concepts”, Peacocke presenta un argumento a favor del no-conceptualismo derivado de las condiciones de posesión de los conceptos observacionales. En este trabajo, planteo dos objeciones a este argumento. Primero, sostengo que si los contenidos perceptivos son contenidos de escenario, entonces las experiencias perceptivas no pueden representar las circunstancias especificadas por las condiciones de aplicación de los conceptos observacionales y, por lo tanto, no pueden desempeñar los roles semánticos y epistémicos que Peacocke quiere que jueguen en el condiciones de posesión de estos conceptos. En segundo lugar, sostengo que si los contenidos perceptivos son protoproposiciones, entonces la explicación de Peacocke acerca de las condiciones de posesión de los conceptos observacionales cae en el mito de lo dad

Kinetics of the one-dimensional voter model with long-range interactions

The one-dimensional long-range voter model, where an agent takes the opinion of another at distance $r$ with probability $\propto r^{-\alpha}$, is studied analytically. The model displays rich and diverse features as $\alpha$ is changed. For $\alpha >3$ the behavior is similar to the one of the nearest-neighbor version, with the formation of ordered domains whose typical size grows as $R(t)\propto t^{1/2}$ until consensus (a fully ordered configuration) is reached. The correlation function $C(r,t)$ between two agents at distance $r$ obeys dynamical scaling with sizeable corrections at large distances $r>r^*(t)$, slowly fading away in time. For $2< \alpha \le 3$ violations of scaling appear, due to the simultaneous presence of two lengh-scales, the size of domains growing as $t^{(\alpha-2)/(\alpha-1)}$, and the distance $L(t)\propto t^{1/(\alpha-1)}$ over which correlations extend. For $\alpha \le 2$ the system reaches a partially ordered stationary state, characterised by an algebraic correlator, % $C(r)\propto r^{-(2-\alpha)}$, whose lifetime diverges in the thermodynamic limit of infinitely many agents, so that consensus is not reached. For a finite system escape towards the fully ordered configuration is finally promoted by development of large distance correlations. In a system of $N$ sites, global consensus is achieved after a time $T \propto N^2$ for $\alpha>3$, $T \propto N^{\alpha-1}$ for $2<\alpha \le 3$, and $T \propto N$ for $\alpha \le 2$.Comment: 16 pages, 9 figure

Generic features of the fluctuation dissipation relation in coarsening systems

The integrated response function in phase-ordering systems with scalar, vector, conserved and non conserved order parameter is studied at various space dimensionalities. Assuming scaling of the aging contribution $\chi_{ag} (t,t_w)= t_w ^{-a_\chi} \hat \chi (t/t_w)$ we obtain, by numerical simulations and analytical arguments, the phenomenological formula describing the dimensionality dependence of $a_\chi$ in all cases considered. The primary result is that $a_\chi$ vanishes continuously as $d$ approaches the lower critical dimensionality $d_L$. This implies that i) the existence of a non trivial fluctuation dissipation relation and ii) the failure of the connection between statics and dynamics are generic features of phase ordering at $d_L$.Comment: 6 pages, 5 figure

Concepts: neither Representations nor Abilities but Rules

Philosophers have always tried to explain what concepts are. Currently, most neo- Fregean philosophers identify concepts with abilities peculiar to cognitive agents. Philosophers who defend a psychological view, in contrast, identify concepts with representations located in the mind. In this paper, I argue that concepts should be understood neither in terms of mental representations nor in terms of abilities. Concepts, I argue, are rules for sorting an inferring. To support this, I follow Ginsborg’s Kantian conception of concepts. Nevertheless, unlike Ginsborg, I provide an explanation of the cognitive relationship between concepts and thinkers that presupposes no linguistic awareness of any normative concept. In doing so, a dispositional approach to the normativity of concepts is proposed

Experiencia y justificación: Variedades del contenido perceptivo

Desde sus inicios la filosofía se ha interesado en el fenómeno de la percepción. Los problemas vinculados a la naturaleza de los contenidos perceptivos y sus relaciones con la cognición han despertado a lo largo de los siglos grandes y profundas reflexiones filosóficas, volviéndose objeto de interés no sólo para la filosofía de la mente, sino también para la epistemología, la metafísica, la ética y para muchas otras disciplinas filosóficas y científicas. En la actualidad, los estudios sobre la percepción constituyen una serie de discusiones provenientes de distintas disciplinas filosóficas y científicas, que en muchos casos no parecen tener en común más que su interés por un mismo objeto de estudio. Dentro del casi inagotable número de discusiones que conforman estos estudios, dos son, posiblemente, las que mayor atractivo e interés han despertado en la escena filosófica actual: (a) el debate entre conceptualistas y no-conceptualistas en torno a la naturaleza del contenido perceptivo, y (b) el debate en epistemología acerca del carácter justificatorio de la experiencia perceptiva. Enmarcado en estos debates, el presente proyecto de investigación tiene como objetivo examinar distintas variantes conceptualistas y no-conceptualistas del contenido perceptivo, a fin de comparar y evaluar, a la luz del debate epistemológico entre internistas y externistas, sus virtudes y defectos para dar cuenta del carácter justificatorio de la experiencia perceptiva. En este sentido, el proyecto busca concretar una serie de objetivos específicos -entre los que se destacan: (i) evaluar los distintos intentos no-conceptualistas que se han ofrecido para explicar las relaciones racionales o de justificación entre percepciones y creencias; (ii) investigar si las posiciones no-conceptualistas pueden explicar las relaciones racionales entre percepciones y creencias desde un punto de vista internista sin caer en el mito de lo dado; e (iii) investigar si las posiciones conceptualistas son compatibles con una visión internista mínima de la justificación epistémica-, a fin de evaluar la posibilidad de articular y defender una variante conceptualista mínima que, partiendo de un enfoques anti-intelectualista (acerca de la posesión de conceptos) e internista mínimo (acerca del modo que las experiencias justifican creencias), proporcione una explicación adecuada de las propiedades epistémicas de la percepción.Fil: Castellano, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Humanidades. Universidad Nacional de Córdoba. Instituto de Humanidades; Argentin

Contenidos mentales y experiencia perceptiva: davidson y rorty en torno a la justificación epistémica

El empirismo afirma que la experiencia nos provee de ciertos contenidos que, siendo objetos ante la mente de los cuales tenemos un conocimiento directo e infalible, nos sirven para justificar todo el edificio del conocimiento. Davidson sostiene que tales objetos no pueden desempeñar ningún papel justificatorio y que, por este motivo, debemos abandonar la noción de representación. Siguiendo la misma dirección, Rorty objeta la tesis que concibe el conocimiento como un conjunto de representaciones privilegiadas y defiende una posición anti-representacionista. El presente trabajo tiene como objetivos (a) reconstruir los argumentos de Davidson y Rorty en contra del representacionismo y del rol justificatorio de la experiencia perceptiva, y (b) evaluar a la luz de sus conclusiones la posibilidad de preservar las nociones de representación y experiencia en el ámbito de la epistemología

Non-conceptualism, observational concepts, and the given

In “Study of Concepts”, Peacocke puts forward an argument for non-conceptualism derived from the possession conditions of observational concepts. In this paper, I raise two objections to this argument. First, I argue that if non-conceptual perceptual contents are scenario contents, then perceptual experiences cannot present perceivers with the circumstances specified by the application conditions of observational concepts and, therefore, they cannot play the semantic and epistemic roles Peacocke wants them to play in the possession conditions of these concepts. Second, I argue that if non-conceptual perceptual contents are protopropositions, then Peacocke’s account of the possession conditions of observational concepts falls into the Myth of the Given