An exercise on developing an ontology-epistemology about schizophrenia and neuroanatomy

This paper describes preliminary ideas on formalizing some concepts of neuroanatomy into ontological and epistemological terms. We envisage the application of this ontology on the assimilation of facts about medical knowledge about neuroimages from schizophrenic patients

Magnetic fields and the Weyl tensor in the early universe

We have solved the Einstein-Maxwell equations for a class of isotropic metrics with constant spatial curvature in the presence of magnetic fields. We consider a slight modification of the Tolman averaging relations so that the energy-momentum tensor of the electromagnetic field possesses an anisotropic pressure component. This inhomogeneous magnetic universe is isotropic and its time evolution is guided by the usual Friedmann equations. In the case of flat universe, the space-time metric is free of singularities (except the well-known initial singularity at t = 0). It is shown that the anisotropic pressure of our model has a straightforward relation to the Weyl tensor. We also analyze the effect of this new ingredient on the motion of test particles and on the geodesic deviation of the cosmic fluid.Comment: 10 pages, 2 figures, new conceptual treatment of the early phenomenological work arXiv:1301.3079. Matches published versio

Cooperativity of a few quantum emitters in a single-mode cavity

We theoretically investigate the emission properties of a single-mode cavity coupled to a mesoscopic number of incoherently pumped quantum emitters. We propose an operational measure for the medium cooperativity, valid both in the bad and in the good cavity regimes. We show that the opposite regimes of subradiance and superradiance correspond to negative and positive cooperativity, respectively. The lasing regime is shown to be characterized by nonnegative cooperativity. In the bad cavity regime we show that the cooperativity defines the transitions from subradiance to superradiance. In the good cavity regime it helps to define the lasing threshold, also providing distinguishable signatures indicating the lasing regime. Increasing the quality of the cavity mode induces a crossover from the solely superradiant to the lasing regime. Furthermore, we verify that lasing is manifested in a wide range of positive cooperative behavior, showing that stimulated emission and superradiance can coexist. The robustness of the cooperativity is studied with respect to experimental imperfections, such as inhomogeneous broadening and pure dephasing

Port Efficiency and Regional Development

This paper attempts to elucidate one of the mechanisms that link trade barriers, in the form of port costs, and subsequent growth and regional inequality. Not only inland costs can be perceived as a further barrier to link trade liberalization and growth (Haddad and Perobelli, 2005), but also port costs. Unlike highway link, congestion at port may have severe impacts spread over space and time whereas highway link congestion may be resolved within several hours. Since port is part of the transportation network, any congestion/disruption is likely to ripple throughout the hinterland. In this sense, it is important to model properly the role nodal congestion plays in a context of spatial models and international trade. Thus, we have developed a spatial CGE model integrated to a transport network system in order to simulate the impacts of increases in port efficiency in a context of trade liberalization. The role of ports of entry and ports of exit are explicitly considered in order to grasp the holistic picture in an integrated interregional system.

Conditions for stable equilibrium in Cournot duopoly models with tax evasion and time delay

We provide conditions for stable equilibrium in Cournot duopoly models with tax evasion and time delay. We prove that our conditions actually imply asymptotically stable equilibrium and delay independence. Conditions include the same marginal cost and equal probability for evading taxes. We give examples of cost and inverse demand functions satisfying the proposed conditions. Some economic interpretations of our results are also included.Comment: Major revision performed, includes title change and correction of some proofs. 14 pages, 1 figur