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How short-term variation influence the relative importance of environmental and spatial factors associated to anuran dissimilarity composition
(Universidade Federal de São Carlos, 2018-08-10) Mello, Flávia Gomes de; Silva, Fernando Rodrigues da; https://lattes.cnpq.br/8543094930527221; https://lattes.cnpq.br/0916793520798473
Understanding the processes that create the patterns of species composition and biodiversity variation across the space has been one of the main topics within the theory of metacommunities. However, most studies rely on static snapshots of community data and few studies have examined the importance of including temporal variability. Here, we examined beta diversity distribution of anuran community composition through three years and considering the whole period of study at different spatial extents in the Brazilian Atlantic Forest: i) seven inland communities; ii) seven coastal communities; and iii) communities pooled together. We partitioned total beta diversity into species replacement and nestedness-resultant components then we used deviance partitioning to explore the relative importance of environmental and spatial factors explaining the distribution of anuran community changes over the years. Species replacement was the predominant component of anuran beta diversity, but average values of species replacement and nestedness-resultant were not congruent across the years. We observed that average values of beta diversity components decrease when species composition of whole period of study are pooled together and increase with increasing spatial extent. Furthermore, our results indicate that Brazilian Atlantic Forest anuran community compositions are highly dynamic in space and time, and the factors explaining the distribution of species replacement and nestedness-resultant are dependent of the sampling year and spatial extent. Thus, metacommunity studies that do not evaluate different spatial and temporal changes should be cautious about the generality of their biological conclusions.
Demarcando vestígios: definindo (o território de) indígenas em isolamento voluntário na Terra Indígena Massaco
(Universidade Federal de São Carlos, 2018-08-10) Pereira, Amanda Villa; Vander Velden, Felipe Ferreira; https://lattes.cnpq.br/7289231173735671; https://lattes.cnpq.br/0894991712266024
The presence of reports in the big mass media spreading the existence of isolated indigenous people in the Amazon forest has grown exponentially over the last years. Such movement is associated mainly due to the onslaughts of a “developmental” nature that is moving forward to lands that are most wanted from the predatory capitalism, along with persistent illegal activities looking for timber and other resources from the forest. Yet, Brazil is a reference when it comes to protection measures to such indigenous communities, and this reputation is due mostly to policies related to demarcation of lands, highlighting the demarcation of an indigenous area exclusively to isolated people in 1996: the indigenous land called Massaco, in the state of Rondônia. In order to enable the land demarcation, it was necessary to create innovations regarding demarcation procedures, in which, as a matter of course, must host the attendance of the indigenous themselves when defining their traditional territory. Regarding the Massaco’s area, it was by the track and traces from an indigenous group that their territory and existence have been defined, while their image is still being designed as an ongoing study of the artifacts found, forsaken Camps, appearance reports and distance observations: they cannot be heard, obviously, therefore they cannot define “their” own territory. The aim of this research is to explore the debates related to the identification of such groups in order to, subsequently, investigate how the land demarcation took place, as well as seeking the knowledge of how their image remains continuously under negotiation at the politics scope for the isolated indigenous people from Rondônia and the Brazilian Amazon.
Na primeira Terra todos eram Mbya: cotidiano na aldeia entre muitos "tipos de gente"
(Universidade Federal de São Carlos, 2018-08-10) Ferreira, Luisa Maria; Villela, Jorge Luiz Mattar; https://lattes.cnpq.br/8301325600502054; https://lattes.cnpq.br/2936631506663149
This research has as its theme the relations between the Guarani Mbya of the Ribeirão Silveira Indigenous Land and other “kind of people”, a category of thought adopted by me, which has awakened my reflection on the meanings attributed by the Mbya, that is: animals, plants, places, dead, beings and “owners”. From living together in this community, at the foot of Serra do Mar, on the north coast of São Paulo, I intend to demonstrate in this ethnography, the importance given by the Guarani Mbya to other “kind of people”. My aim is to find out to what extent their existenice in tekoa is necessary to promote and ensure the teko porã (“good life”) they desire. That is, this work is the search to find the Guarani Mbya questions, guided by the questions they ask themselves, containing the problems they face. Such questions drive and motivate their daily actions and are present in the processes of reflection and knowledge that the Guarani have, as much as we researchers or not, Westerners or not. What can we learn about people from the questions they ask themselves about their way of life? What about the life forms that surround them? The Guarani-Mbya belong to a subgroup of the Guarani people. Speakers of Mbya Guarani, a Guarani language belonging to the Tupi-Guarani family of the Tupi trunk. They are located in the densest and oldest region of non-indigenous occupation in the country. Present according to data from the Centro de Trabalho Indigenista (CTI) in more than a hundred villages in the South and Southeast of Brazil (São Paulo, Rio de Janeiro, Espírito Santo, Paraná, Santa Catarina and Rio Grande do Sul). They are also present in the states of Pará and Tocantins, in addition to Bolivia, Argentina, Paraguay and Uruguay. With regard to language, Mbya Guarani and Nhandeva speakers live in the Ribeirão Silveira TI. A good part of the population is married or descends from marriages between members of both Guarani subgroups, as I was able to ascertain. For the development of this work, a bibliographical study was made on this people. To this was associated the author's coexistence, for eight months, in the tribe as a way of reporting and observing their daily lives and all the questions raised by me, presented above. The research consists of a case study, containing reports and transcripts.
Inferência bayesiana em modelos de volatilidade estocástica usando métodos de Monte Carlo Hamiltoniano
(Universidade Federal de São Carlos, 2018-08-10) Dias, David de Souza; Ehlers, Ricardo Sandes; https://lattes.cnpq.br/4020997206928882; https://lattes.cnpq.br/1075237626573361
This paper presents a study using Bayesian approach in stochastic volatility models for modeling financial time series, using Hamiltonian Monte Carlo methods (HMC). We propose the use of other distributions for the errors of the equation at stochastic volatiliy model, besides the Gaussian distribution, to treat the problem as heavy tails and asymmetry in the returns. Moreover, we use recently developed information criteria WAIC and LOO that approximate the crossvalidation methodology, to perform the selection of models. Throughout this work, we study the quality of the HMC methods through examples, simulation study and application to dataset. In addition, we evaluated the performance of the proposed models and methods by calculating estimates for Value at Risk (VaR) for multiple time horizons.
Influência da mistura gasosa e da temperatura no processo de nitrocarbonetação a plasma do aço DIN 100Cr6
(Universidade Federal de São Carlos, 2018-08-10) Fontes, Marcos Alves; Nascente, Pedro Augusto de Paula; https://lattes.cnpq.br/1387043320265189; https://lattes.cnpq.br/9159934014167252
The surface treatments of metal alloys allow improving the surface qualities by the deposition of another material or by surface modification, producing coatings. The nitrocarburizing, considered one of the most important thermochemical treatments, involves the simultaneous diffusion of N and C into the surface. Understanding and controlling the formation of the nitrocarburized layer have considerable industrial interest due to the improvements regarding wear, fatigue, and corrosion resistances on the metals and their alloys. In the present work, surface modification by plasma nitrocarburizing was performed in a DIN 100Cr6 steel. The studied process parameters were the treatment temperature (550 and 600°C) and methane concentration in the gas mixture (0, 1.0, 1.5, and 2.0%), whereas the treatment time was fixed in 2h. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses, as well as wear resistance and micro-hardness tests were used to characterize the samples. The results show that the modifications on the material surface considerably improve the mechanical properties such as hardness and wear resistance, by the formation of nitrides. The compound layer composition and morphology are quite sensitive to the temperature and chemical composition of the treatment atmosphere. Increasing the CH4 concentration on the gas mixture contributes to the formation of the epsilon-Fe2-3 (C,N) phase, considerably enhancing the wear resistance and microhardness, and the use of high N2 concentration induces the production of a micro-porosity layer. Ferritic nitrocarburizing promotes thinner micro-porosity and compound layers, with predominant epsilon phase, and higher superficial microhardness, and the austenitic nitrocarburizing produces a thicker micro-porosity and compound layers, with predominant epsilon and gama’-Fe4N phases on the compound layer.