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Consciência não-linear: de William James aos sistemas dinâmicos
(Universidade Federal de São Carlos, 2004-04-02) Kinouchi, Renato Rodrigues; Abib, José Antônio Damásio
William James’s scientific psychology was developed in order to surpass precedent approaches such as both Rationalism and Associationism. His masterpiece, The Principles of Psychology (1890), has been a mark in the history of psychological science because James already took cognitive processes as relations between the organisms and their environments. In this doctoral work, three contemporaneous cognitive theories are interpreted through James’s ideas: Artificial Intelligence, Connectionism and Dynamical Systems. This analysis, however, neither concerns scientific psychology nor philosophy of mind — in precise terms, the former examines psychological facts, and the later categorizes mental phenomena. Notwithstanding, we have done a conceptualcomparative study that categorizes the explanations proposed by those three cognitive theories. To be sure, this work should be labelled as a Philosophy of Cognitive Science. It examines theories concerned with cognition; so it is a philosophical analysis on cognitive science
O papel da interação elétron-elétron no regime Hall quântico interio
(Universidade Federal de São Carlos, 2004-04-02) Silva, Sanderson Francisco Fernandes Pereira da; Studart Filho, Nelson; https://lattes.cnpq.br/0451310772113076
Experimental and theoretical studies of the aspects of particle-like and collective behavior of electrons in the proximity of the edges of two-dimensional (2DES) and quasi-one-dimensional (Q1DES) systems, named quantum wires (QWs), in semiconductor heterostructures reveal the important role of the electron-electron interaction on the edge states in the integer quantum Hall regime (IQHR). In this thesis we treat two essentially diﬀerent problems concerning the eﬀects of the electron-electron interaction in low-dimensional electron system in the IQHR. The first problem is related to the suppression of the spin-splitting of the lowest Landau level (LL) (n = 0) due to many-body eﬀects (the electron-electron interaction including exchange and correlation eﬀects of the edge states) in QWs in the IQHR, where the electron behavior is particle-like. Two scenarios are discussed for the collapse of the IQHR at ν = 1 for an electron channel of eﬀective width W modelling the QW. In the first scenario we assume that there is no electron redistribution in the region limited by W at a critical magnetic field B(1) cr , for which the Fermi level (FL) coincides with the bottom of the highest empty LL, at the threshold of the spin-splitting. For B < B(1) cr the IQHR at ν = 1 is termodinamically unstable. This scenario is analyzed within the generalized local density approximation (GLDA) developed here for the QW, at high magnetic fields - ωc À Ω, where ωc and Ω are the ciclotronic and lateral confinement (which we assume as parabolic one) frequencies, respectively. In the second scenario, we consider the possibility of a transition for the IQHR at ν = 2 with an eﬀective width W/2, at a critical magnetic field B(2) cr . In this scenario, the collapse of the IQHR at ν = 1 is studied within the Hartree-Fock approximation (HFA), when the bare factor g0 is neglected (this is a good approximation for QWs based on GaAs). We show that the contribution for the total energy coming from the direct interaction (Hartree term) has a strong eﬀect on B(2) cr due to the high electron redistribution inside the narrow channel that defines the QW at B(2) cr . In both scenarios, the enhanced spin-splitting by exchange is suppressed at the critical magnetic field. From our results, we conclude that only the first scenario explains all the experimental findings obtained by Wróbel et al. and Pallecchi et al.. In the second problem, where the collective aspects of the electron system are dominant, we study the influence of the temperature on the dispersion relation and the spatial structure of the edge magnetoplasmons (EMPs) in wide electron channels in the RHQI at ν = 1 (2) and 4, in the range ¯hωc À kB T À ¯hvH gn/2 0, for diﬀerent dissipation regimes, by extending the pioneering work by Balev and Studart; here, ¯h is the constant of Planck constant (by 2π), kB is the constant of Boltzmann, vH gn is the group velocity (in Hartree approximation) of the edge states of n-th LL, and 0 is the magnetic lenght. A new mode called the edge helicon is found which is the only one that survive for very strong dissipation regime. For a sake of completeness, the general picture of the other modes is presented in the weak dissipation regime. EMPs in the IQHR for ν = 4 are also evaluated for weak dissipation and we find strong renormalization of the pure EMPs when the Coulomb interaction is considered appropriately. In all studied cases the important eﬀect of the gate and the air from a distance d of the wide electron channel is considered.
Certificação ambiental e desenvolvimento sustentável: avaliação para o setor sucroalcooleiro localizado na bacia hidrográfica do rio Mogi-Guaçi/SP
(Universidade Federal de São Carlos, 2004-04-02) Rodrigues, Isabel Cristina; Alves, Francisco José da Costa; https://lattes.cnpq.br/9183120186518337
The sugar cane culture always was been associated, throughout its history, with ambient degradation and social contingencies. The positioning, on the part of the sugar cane industry, with relation to the negative impacts of its activity on the environment has been defensive, limited to fulfill the legal impositions. In this context, calls the attention the initiative of some sugar cane plants that had decided to produce certified sugar cane and certified organic sugar. This work discusses the motivations that had taken these plants to adopt this system of production and the factors that had concurred for this decision. It starts from the hypothesis that the basic motivation for this decision was the search for a differentiated product, with characteristics valued for the market, and, therefore, apt to increase the profit tax and valuing the capital. The work also allows analyzing until with point the premises of the Sustainable Development are observed by the plants when of its decisions of investments. From of the definition of that the sustainable development must incorporate the regional questions, the sugar cane industry in the Hydrographic Basin of the river Mogi-Guaçu was chosen for the study, because it is in this basin that is found the biggest productive portion of this sector in the country. The research carried through in one of the productive units in the Basin allowed to the construction of a diagnosis of the activity in the regional clipping and a delineation of the necessary changes to the organic production. The resultant diagnosis of the field research allowed concluding that the environment conditions of the plants that had opted to the organic production are significantly improved, but the premises foreseen by the organic certification are incapable to contemplate all the social and environment problems of this activity. The main problems are associated to the extensive exploration of the agricultural activity and the questions of exclusion of workers and small suppliers, generating social problems in the region of the enterprise. The analysis of the plants that had opted to the conversion demonstrates different strategies between them, but the research points out that the motivation that had taken them to decide for the conversion, was directed by the search for a differentiated product. The work concludes that the tools of ambient regulation, based in the market demand, as it is the case of the certificates and labels, is insufficient to contemplate all the premises of the regional sustainable development and that still it becomes necessary the performance of the State and its agencies in the regulation of the access, use and of the occupation of the agricultural space.