6 resultados para Two-color laser fields

em Universidade Federal do Rio Grande do Norte(UFRN)


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This paper proposes to analyse a situation of social drama involving the Krahô Indians (classified in ethnology as belonging to Jê-Timbira group) and the Museu Paulista of the Universidade de São Paulo, which we can classify as two distinct social fields. The understanding of the drama is conveyed through an examination of each of these fields and the coming together of both on the basis of the positions taken up, within the network of relationships established during the social process, by actors representing both the Krahô field and what we may call here the academic-administrative field. A multi-sited ethnographic approach is adopted, seeking the complexity of the drama and the positions in the aforementioned network, taking into consideration institutional political projects, personal projects and personal trajectories within a historical perspective. The aim is to encourage discussion of the relationship between the formation of the historical-scientific and ethnographic museums and the practices of the anthropological discipline, as well as the social role of these institutions and the processes of signification of objects belonging to the indigenous material culture

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The study of social practices aims to overcome the theoretical dichotomies that insist on separating the individual from the social structures and vice versa. In this sense, the debate between objectivism and subjectivism in the construction of social reality still has occupied much time and reflection of various scholars of the humanities. Pierre Bourdieu has extensive work that seeks to advance in relation to the theoretical framework of traditional sociological explanations. Bourdieu`s approach regarding social practices is considered by some researchers as a synthesis of classical theories and by others as an attempt of complexify contemporary studies on the significance of social life. This thesis sharesthis effort to understand the social practices of agents, aiming to analyze the strategies of social and political leaders of family farming in the territories of Seridó and Apodi in Rio Grande do Norte, and it has as reference the theoretical and methodological concepts of habitus, field and capital, in Bourdieu. Therefore, we studied the trajectories of social leaders, here called agents as family farming in the two locations in Rio Grande do Norte. As techniques and procedures of the study, we resortedto semi-structured interviews, observations, participation in events and other researches. In conclusion, this thesis gives an account of the construction of two different relational fields for the activities of agents of family farming in the territories of Seridó and Apodi. Although the relational fields in the territories have been structured under the same prevailing institutions, which are: church, union and political party, the social practice of agents shows itself from social position and political variety. Even with the similarities and differences identified and analyzed in different fields of construction, the social relations of the agents in the territories result in the construction of gated communities, the social capital that is the substrate which the agents called empowered .

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The usual Ashkin-Teller (AT) model is obtained as a superposition of two Ising models coupled through a four-spin interaction term. In two dimension the AT model displays a line of fixed points along which the exponents vary continuously. On this line the model becomes soluble via a mapping onto the Baxter model. Such richness of multicritical behavior led Grest and Widom to introduce the N-color Ashkin-Teller model (N-AT). Those authors made an extensive analysis of the model thus introduced both in the isotropic as well as in the anisotropic cases by several analytical and computational methods. In the present work we define a more general version of the 3-color Ashkin-Teller model by introducing a 6-spin interaction term. We investigate the corresponding symmetry structure presented by our model in conjunction with an analysis of possible phase diagrams obtained by real space renormalization group techniques. The phase diagram are obtained at finite temperature in the region where the ferromagnetic behavior is predominant. Through the use of the transmissivities concepts we obtain the recursion relations in some periodical as well as aperiodic hierarchical lattices. In a first analysis we initially consider the two-color Ashkin-Teller model in order to obtain some results with could be used as a guide to our main purpose. In the anisotropic case the model was previously studied on the Wheatstone bridge by Claudionor Bezerra in his Master Degree dissertation. By using more appropriated computational resources we obtained isomorphic critical surfaces described in Bezerra's work but not properly identified. Besides, we also analyzed the isotropic version in an aperiodic hierarchical lattice, and we showed how the geometric fluctuations are affected by such aperiodicity and its consequences in the corresponding critical behavior. Those analysis were carried out by the use of appropriated definitions of transmissivities. Finally, we considered the modified 3-AT model with a 6-spin couplings. With the inclusion of such term the model becomes more attractive from the symmetry point of view. For some hierarchical lattices we derived general recursion relations in the anisotropic version of the model (3-AAT), from which case we can obtain the corresponding equations for the isotropic version (3-IAT). The 3-IAT was studied extensively in the whole region where the ferromagnetic couplings are dominant. The fixed points and the respective critical exponents were determined. By analyzing the attraction basins of such fixed points we were able to find the three-parameter phase diagram (temperature £ 4-spin coupling £ 6-spin coupling). We could identify fixed points corresponding to the universality class of Ising and 4- and 8-state Potts model. We also obtained a fixed point which seems to be a sort of reminiscence of a 6-state Potts fixed point as well as a possible indication of the existence of a Baxter line. Some unstable fixed points which do not belong to any aforementioned q-state Potts universality class was also found

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This thesis encompasses the integration of geological, geophysical, and seismological data in the east part of the Potiguar basin, northeastern Brazil. The northeastern region is located in South American passive margin, which exhibits important areas that present neotectonic activity. The definition of the chronology of events, geometry of structures generated by these events, and definition of which structures have been reactivated is a necessary task in the region. The aims of this thesis are the following: (1) to identify the geometry and kinematics of neotectonic faults in the east part of the Potiguar basin; (2) to date the tectonic events related to these structures and related them to paleoseismicity in the region; (3) to present evolutional models that could explain evolution of Neogene structures; (4) and to investigate the origin of the reactivation process, mainly the type of related structure associated with faulting. The main type of data used comprised structural field data, well and resistivity data, remote sensing imagery, chronology of sediments, morphotectonic analysis, x-ray analysis, seismological and aeromagnetic data. Paleostress analysis indicates that at least two tectonic stress fields occurred in the study area: NSoriented compression and EW-oriented extension from the late Campanian to the early Miocene and EW-oriented compression and NS-oriented extension from the early Miocene to the Holocene. These stress fields reactivated NE-SW- and NW-SE-trending faults. Both set of faults exhibit right-lateral strike-slip kinematics, associated with a minor normal component. It was possible to determine the en echelon geometry of the Samambaia fault, which is ~63 km long, 13 km deep, presents NE-SW trend and strong dip to NW. Sedimentfilled faults in granite rocks yielded Optically Stimulated Luminescence (OSL) and Single-Aliquot Regeneration (SAR) ages at 8.000 - 9.000, 11.000 - 15.000, 16.000 - 24.000, 37.000 - 45.500, 53.609 - 67.959 e 83.000 - 84.000 yr BP. The analysis of the ductile fabric in the João Câmara area indicate that the regional foliation is NE-SW-oriented (032o - 042o), which coincides with the orientation of the epicenters and Si-rich veins. The collective evidence points to reactivation of preexisting structures. Paleoseismological data suggest paleoseismic activity much higher than the one indicated by the short historical and instrumental record

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The structural knowledge of the western portion of the Potiguar Basin is still in its infancy, especially these related to NW-trending fault systems. This paper analyzes the Poço Verde-Caraúbas Fault System, which was initially recognized in subsurface. The activities involved in this study correspond to remote-sensing analysis and, in particular, to the geometric and kinematic analysis of post-rift sequences of the basin. In addition, the study aimed to determine the stress fields operating in the area. The studies were carried out in an area of 1,000 km², located in the western portion of Potiguar Basin along the Poço Verde-Caraúbas Fault System, Rio Grande do Norte State. The remote sensing imagery indicates a predominance of NW-SE-trending lineaments, consistent with the fault system under study, followed by the NE-SW, N-S and E-W directions. The tectonic structures mapped were analyzed only in outcrops of the Jandaíra Formantion. They are joints (filled or not) in all directions, but with predominance of the NW-trending joints. Faults are usually N-S-trending normal faults and NW-SE and NE-SW-trending strike-slip faults. Geodynamic analysis identified two tectonic stress fields: the first field, "Field 1" is represented by an N-S-trending horizontal compression and E-W-trending horizontal extension. This field affected the Potiguar Basin at least until the Miocene. The second field, "Field 2", is represented by an E-W-trending horizontal compression and N-S-trending horizontal extension. This is the present-day stress field and has affected the Potiguar basin since the Pliocene

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This paper proposes to analyse a situation of social drama involving the Krahô Indians (classified in ethnology as belonging to Jê-Timbira group) and the Museu Paulista of the Universidade de São Paulo, which we can classify as two distinct social fields. The understanding of the drama is conveyed through an examination of each of these fields and the coming together of both on the basis of the positions taken up, within the network of relationships established during the social process, by actors representing both the Krahô field and what we may call here the academic-administrative field. A multi-sited ethnographic approach is adopted, seeking the complexity of the drama and the positions in the aforementioned network, taking into consideration institutional political projects, personal projects and personal trajectories within a historical perspective. The aim is to encourage discussion of the relationship between the formation of the historical-scientific and ethnographic museums and the practices of the anthropological discipline, as well as the social role of these institutions and the processes of signification of objects belonging to the indigenous material culture