Semipurity of tempered Deligne cohomology

In this paper we define the formal and tempered Deligne cohomology groups, that are obtained by applying the Deligne complex functor to the complexes of formal differential forms and tempered currents respectively. We then prove the existence of a duality between them, a vanishing theorem for the former and a semipurity property for the latter. The motivation of these results comes from the study of covariant arithmetic Chow groups. The semi-purity property of tempered Deligne cohomology implies, in particular, that several definitions of covariant arithmetic Chow groups agree for projective arithmetic varieties

Dynamical quenching and annealing in self-organization multiagent models

We study the dynamics of a generalized Minority Game (GMG) and of the Bar Attendance Model (BAM) in which a number of agents self-organize to match an attendance that is fixed externally as a control parameter. We compare the usual dynamics used for the Minority Game with one for the BAM that makes a better use of the available information. We study the asymptotic states reached in both frameworks. We show that states that can be assimilated to either thermodynamic equilibrium or quenched configurations can appear in both models, but with different settings. We discuss the relevance of the parameter $G$ that measures the value of the prize for winning in units of the fine for losing. We also provide an annealing protocol by which the quenched configurations of the GMG can progressively be modified to reach an asymptotic equlibrium state that coincides with the one obtained with the BAM.Comment: around 20 pages, 10 figure

Thermal treatment of the minority game

We study a cost function for the aggregate behavior of all the agents involved in the Minority Game (MG) or the Bar Attendance Model (BAM). The cost function allows to define a deterministic, synchronous dynamics that yields results that have the main relevant features than those of the probabilistic, sequential dynamics used for the MG or the BAM. We define a temperature through a Langevin approach in terms of the fluctuations of the average attendance. We prove that the cost function is an extensive quantity that can play the role of an internal energy of the many agent system while the temperature so defined is an intensive parameter. We compare the results of the thermal perturbation to the deterministic dynamics and prove that they agree with those obtained with the MG or BAM in the limit of very low temperature.Comment: 9 pages in PRE format, 6 figure

Seismic assessment of the medieval Armenian church in Famagusta, Cyprus

This paper presents the analysis of the structural performance of the Armenian Church in Famagusta, Cyprus. Visual and photographic survey, non-destructive testing and numerical evaluation, using a tridimensional finite element model, are included. The non-linear behavior is analyzed under gravity and seismic loading, and pushover and time-history analysis are performed, including in both cases bidirectional loading. Results are studied in terms of capacity curves and damage patterns. The influence of the Church mass-distribution is also evaluated. As a result, the analysis estimates an adequate safety level of the building and various real damage features of the Church are justified and attributed to seismic actions.The authors acknowledge the support from Dr. Michael Walsh and the Nanyang Technological University of Singapore. Further credits are given to Solvotek Engineering, from Turkey, which performed the laser scans of the Church.During the realization of this study, the first author was an European Commission Erasmus Mundus grant holder of the Advanced Masters in Structural Analysis of Monuments and Historical Constructions, as well as grant holder of the Mexican Secretariat of Public Education (SEP) and the Mexican Government

GABA Neuron Alterations, Cortical Circuit Dysfunction and Cognitive Deficits in Schizophrenia

Schizophrenia is a brain disorder associated with cognitive deficits that severely affect the patients' capacity for daily functioning. Whereas our understanding of its pathophysiology is limited, postmortem studies suggest that schizophrenia is associated with deficits of GABA-mediated synaptic transmission. A major role of GABA-mediated transmission may be producing synchronized network oscillations which are currently hypothesized to be essential for normal cognitive function. Therefore, cognitive deficits in schizophrenia may result from a GABA synapse dysfunction that disturbs neural synchrony. Here, we highlight recent studies further suggesting alterations of GABA transmission and network oscillations in schizophrenia. We also review current models for the mechanisms of GABA-mediated synchronization of neural activity, focusing on parvalbumin-positive GABA neurons, which are altered in schizophrenia and whose function has been strongly linked to the production of neural synchrony. Alterations of GABA signaling that impair gamma oscillations and, as a result, cognitive function suggest paths for novel therapeutic interventions

Quantitative analysis of shadow X-ray Magnetic Circular Dichroism Photo-Emission Electron Microscopy

Shadow X-ray Magnetic Circular Dichroism Photo-Emission Electron Microscopy (XMCD-PEEM) is a recent technique, in which the photon intensity in the shadow of an object lying on a surface, may be used to gather information about the three-dimensional magnetization texture inside the object. Our purpose here is to lay the basis of a quantitative analysis of this technique. We first discuss the principle and implementation of a method to simulate the contrast expected from an arbitrary micromagnetic state. Text book examples and successful comparison with experiments are then given. Instrumental settings are finally discussed, having an impact on the contrast and spatial resolution : photon energy, microscope extraction voltage and plane of focus, microscope background level, electric-field related distortion of three-dimensional objects, Fresnel diffraction or photon scattering

Espacios rupestres como «obras abiertas»: una mirada a los procesos de confección y transformación de los abrigos con arte rupestre del este de Catamarca (Argentina)

In this paper we attempt to advance the understanding of the process of painting in caves with rock art at Ancasti’s Highlands (Catamarca Province, Argentina) from chemical analysis of pigment mixtures with which the paintings have been made. Thus, we suggest the possibility of understanding some of the art in these caves as «open works», i.e.: as the result of addition of motives over a process whose duration, perhaps long, we do not know.En este trabajo intentamos avanzar en el conocimiento del proceso de pintado de las cuevas con arte rupestre de la Sierra de Ancasti (Provincia de Catamarca, Argentina) a partir del análisis químico de las mezclas pigmentarias con las que fueron realizadas las pinturas. De este modo, planteamos la posibilidad de comprender algunos de estos abrigos pintados como «obras abiertas», es decir, como el resultado del agregado de motivos a lo largo de un proceso cuya duración, quizás larga, aún no conocemos

Self-Segregation vs. Clustering in the Evolutionary Minority Game

Complex adaptive systems have been the subject of much recent attention. It is by now well-established that members (`agents') tend to self-segregate into opposing groups characterized by extreme behavior. However, while different social and biological systems manifest different payoffs, the study of such adaptive systems has mostly been restricted to simple situations in which the prize-to-fine ratio, $R$, equals unity. In this Letter we explore the dynamics of evolving populations with various different values of the ratio $R$, and demonstrate that extreme behavior is in fact {\it not} a generic feature of adaptive systems. In particular, we show that ``confusion'' and ``indecisiveness'' take over in times of depression, in which case cautious agents perform better than extreme ones.Comment: 4 pages, 4 figure