Phase transitions in multi-cut matrix models and matched solutions of Whitham hierarchies

We present a method to study phase transitions in the large N limit of matrix models using matched solutions of Whitham hierarchies. The endpoints of the eigenvalue spectrum as functions of the temperature are characterized both as solutions of hodograph equations and as solutions of a system of ordinary differential equations. In particular we show that the free energy of the matrix model is the quasiclassical tau-function of the associated hierarchy, and that critical processes in which the number of cuts changes in one unit are third-order phase transitions described by C1 matched solutions of Whitham hierarchies. The method is illustrated with the Bleher-Eynard model for the merging of two cuts. We show that this model involves also a birth of a cut

Fine structure in the large n limit of the non-hermitian Penner matrix model

In this paper we apply results on the asymptotic zero distribution of the Laguerre polynomials to discuss generalizations of the standard large $n$ limit in the non-hermitian Penner matrix model. In these generalizations $g_n n\to t$, but the product $g_n n$ is not necessarily fixed to the value of the 't Hooft coupling $t$. If $t>1$ and the limit $l = \lim_{n\rightarrow \infty} |\sin(\pi/g_n)|^{1/n}$ exists, then the large $n$ limit is well-defined but depends both on $t$ and on $l$. This result implies that for $t>1$ the standard large $n$ limit with $g_n n=t$ fixed is not well-defined. The parameter $l$ determines a fine structure of the asymptotic eigenvalue support: for $l\neq 0$ the support consists of an interval on the real axis with charge fraction $Q=1-1/t$ and an $l$-dependent oval around the origin with charge fraction $1/t$. For $l=1$ these two components meet, and for $l=0$ the oval collapses to the origin. We also calculate the total electrostatic energy $\mathcal{E}$, which turns out to be independent of $l$, and the free energy $\mathcal{F}=\mathcal{E}-Q\ln l$, which does depend of the fine structure parameter $l$. The existence of large $n$ asymptotic expansions of $\mathcal{F}$ beyond the planar limit as well as the double-scaling limit are also discussed

Measuring Regional Cohesion Effects of Large-scale Transport Infrastructure Investments: An Accessibility Approach.

Cohesion is considered one of the main policy goals both at a EU an national level. However, there is currently a lack of a common approach to measure cohesion effects of large-scale transport infrastructure investments. Accessibility indicators have an unexploited potential in transportation assessment methodologies. Accessibility is considered an added value of locations, which represents one of the elements contributing to a region’s welfare. Therefore, spatial distribution of accessibility may be used as a proxy to assess regional cohesion. This paper suggests an approach consisting in measuring changes in the spatial distribution of four different accessibility indicators, computed and mapped using a GIS support. Cohesion is subsequently measured calculating a set of inequality indices of the resulting accessibility distribution. It is possible then to assess whether disparities in regional accessibility are increased or reduced after the implementation of a new transport infrastructure. This approach is tested assessing regional cohesion effects of road and rail network developments in Spain in the period 1992-2004. Comparing the results obtained with accessibility indicators and inequality indices allows identifying the main critical factors and sources of bias. The conclusion is that for the rode mode, cohesion has improved, while regional disparities have increased for the rail mode

The late merging phase of a galaxy cluster : XMM EPIC Observations of A3266

We present a mosaic of five XMM-Newton observations of the nearby ($z=0.0594$) merging galaxy cluster Abell 3266. We use the spectro-imaging capabilities of \xmm to build precise (projected) temperature, entropy, pressure and Fe abundance maps. The temperature map exhibits a curved, large-scale hot region, associated with elevated entropy levels, very similar to that foreseen in numerical simulations. The pressure distribution is disturbed in the central region but is remarkably regular on large scales. The Fe abundance map indicates that metals are inhomogeneously distributed across the cluster. Using simple physical calculations and comparison with numerical simulations, we discuss in detail merging scenarios that can reconcile the observed gas density, temperature and entropy structure, and the galaxy density distribution

Disseny d'un sistema d'instrumentació virtual per a la mesura de potència de sistemes autònoms

L'objectiu del treball és dissenyar i desenvolupar un sistema d'instrumentació virtual per adquirir i processar mesures dels transitoris de tensió i corrent presents al commutar l'alimentació de condicionadors de senyal utilitzats en qualsevol sensor autònom. Aquesta estratègia es faria servir per minimitzar el seu consum d'energia. Aquest sistema realitzarà mesures de tensió i corrent de diversos dispositius de forma puntual o periòdica amb un sistema d'adquisició USB de senyals analògics. Es preveu l'implementació d'un mínim de hardware per fer-lo servir conjuntament amb l'esmentat sistema d'adquisició, i el desenvolupament del software que permeti l'enregistrament i processament amb un PC de les dades de tensió i corrent per fer els càlculs de potència i energia consumida en els transitoris de diversos dispositius. El treball es realitzarà en LabView i inclourà les següents activitats: 1.- Anàlisi de les necessitats del sistema: hardware i software. 2.- Especificació del sistema. 3.- Disseny, desenvolupament i verificació del hardware i software. 4.- Realització de mesures amb dispositius bàsics. 5.- Documentació i presentació de resultats

Viaje por las fronteras del campo sociológico. Una cartografía de la investigación social

Sin resume

Long memory in volatility. An investigation on the Central and Eastern European exchange rates

Understanding the evolution of volatility on the financial markets is essential for the comprehension and for the analysis of risk. This paper regards the topic of persistence of volatility in the exchange rates for four Central and Eastern European countries: Czech Republic, Hungary, Poland, and Romania. Persistence in volatility shows how quickly financial markets forget large volatility shocks. The persistence of volatility is addressed as the presence of long-term memory in the second order moment of returns and in absolute returns. The main feature of a long-memory process is that its autocorrelation function decays slower than that of a short memory process, but faster than that of an integrated one. The paper also concerns the implications on risk assessment of detecting long-term memory in the volatility of the exchange rate.peer-reviewe

Asymptotic solution of inflationary T-models in the Hamilton-Jacobi formalism

We use the Hamilton-Jacobi formalism to derive asymptotic solutions to the dynamical equations for inflationary T-models in a flat Friedmann-Lema\^itre-Robertson-Walker spacetime, both in the kinetic-dominance stage and in the slow-roll stage. With an appropriate Pad\'e summation, the expansions for the Hubble parameter in those two stages can be matched, which in turn determines the relation between the expansions for the number of e-folds and allows us to compute the total amount of inflation as a function of the initial data or, conversely, to select initial data that correspond to a fixed total amount of inflation. Using the slow-roll stage expansions, we also derive expressions for the corresponding spectral indexes $n_s$ accurate to order $1/N^2$, and $r$ accurate to order $1/N^3$ in the number of e-folds $N$ in the slow-roll approximation.Comment: 25 pages, 8 figure

STRATEGIES DEVELOPED BY LEADING EU AGRI-FOOD COOPERATIVES IN THEIR GROWTH MODEL

The rationale for this paper is the problem relating to the growth of agricultural cooperatives in Spain in recent years in comparison to increasingly concentrated food distribution, which captures most of the value added. This paper analyses the evolution and status of other countries within Europe where the need for business consolidation has been successfully addressed. For this purpose, there have been identified 7 cases to be studied: Kerry group, Irish Dairy Board, Arla Foods, The Greenery BV, Danish Crown, Agrifirm and DLG. The specific results of interviews with the senior management of this cooperatives were analyzed and organized into four blocks in which the issues raised are grouped (legal and institutional framework, strategic vision, business growth models and market standing). A number of specific aims are also pursued:  Identify the main barriers and problems faced by this type of cooperatives.  Show the strategies developed by leading cooperatives in their sector within the current comparative context.  Become familiar with the different growth models these cooperatives use to achieve and maintain their market standing.Agribusiness,