Navegando por Data de Publicação, começando com "2014-04-28"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 4 de 4

Vespas parasitoides em capítulos de Asteraceae: caracterização da fauna, distribuição e padrões de associação no Cerrado do estado de São Paulo
(Universidade Federal de São Carlos, 2014-04-28) Nascimento, André Rangel; Dias, Angélica Maria Penteado Martins; https://lattes.cnpq.br/8637344058859147; https://lattes.cnpq.br/1936839223951300
This is the first and most complete study of parasitoid wasps fauna associated with endophagous herbivores reared from flower-heads of Asteracea. A total of 36 remnants of Cerrado were sampled around São Paulo states, Brazil. 15,372 specimens of 192 species of parasitoid wasps were reared from 74 species of family Asteraceae. The subfamilies Eulophidae (Chalcidoidea) and Braconidae (Ichneumonoidea) represented most than a half of parasitoid wasps species. In addition to presenting a rich fauna of parasitoids, this study also addresses ecological issues regarding the main determinants of the parasitoid species richness from Brazilian savannah. The availability of food resources has crucial role in determining the species richness of parasitoids. In the first chapter of this thesis, we verified the role of geographical distribution of plants on the accumulation of natural enemies of their endophagous herbivores. In the second chapter, we verified through a path analysis which was the effect of local richness and phylogenetic diversity of plant species and their herbivores endophagous of flower-heads on local parasitoid species richness. In the third chapter we tested through an analysis of randomization if the patterns of the proportions of species of three trophic levels were consistent or stochastic. We conclude that both plants and their associated herbivores play a key role in determining the species richness of parasitoids in the Cerrado biome and the principals determinants of parasitoid wasps species richness were geographical distribution of plants, plant and herbivore richness, and the phytophysiognomy where species live. Due copyrights, all chapters of this thesis can be found published online in Neotropical Entomology, Insect Conservation and Diversity and Biota Neotropica magazines.
Concentração, rivalidades e impactos sobre o risco no mercado bancário brasileiro
(Universidade Federal de São Carlos, 2014-04-28) Bottrel, Mariana Araújo e Silva; Pitelli, Mariusa Momenti; https://lattes.cnpq.br/2810339285129049; https://lattes.cnpq.br/1884762075436436; Aguiar, Danilo Rolim Dias de; http://lattes.cnpq.br/1889207481986151; Moraes, Márcia Azanha Ferraz Dias; http://lattes.cnpq.br/2617570378223458
It is essential that the financial intermediaries operate well in order to offer financial products to attend the society s needs efficiently, providing economic growth. Besides, a healthy banking system is extremely important for the solidity of the financial system of a country and the social welfare. Therefore, it is necessary to study the market structure, with their concentration rates and the possibility to exercise market power of the firms. Also, it is possible to relate the impacts of this market structure to the risks taken by the banks. In order to measure the concentration, it has been used the following techniques: (i) Herfindahl-Hirschman Index (HHI); (ii) Concentration Rates ( CR). To watch the possibility of market power exercising and rivalry, two methods were used: (i) unit root tests; and (ii) unit root tests with panel data. The results show that there has been a large increase in concentration, especially during the beginning of the global financial crisis in 2008. Moreover, it shows that there is possibility of effective rivalry. For the relationship between structure and risk, it has been used a model with panel data, according to Araújo e Jorge Neto (2007). The result was that the relationship between risk and concentration is positive. On conclusion, effective rivalry in the markets studied is possible, which reduces the possibility of the exercise of market power due to an increase in concentration. The concentration may also not have contributed to reduce the risks taken by banks. Keywords: Economic Measures. Econometrics. Commercial Bank. Financial Crisis.
“Compreensão das propriedades estruturais e de superfície de catalisadores de platina promovidos com cério através de técnicas de caracterização in situ sob a reação de deslocamento gás-água”
(Universidade Federal de São Carlos, 2014-04-28) Meira, Debora Motta; Zanchet, Daniela; https://lattes.cnpq.br/0601216568829240; Bueno, José Maria Corrêa; https://lattes.cnpq.br/0157452280626031; https://lattes.cnpq.br/1626800080600447
Pt based catalysts were measured with in situ X ray absorption fine structure spectroscopy (XAFS) to obtain information about the catalyst crystalline structure and electronic properties as a function of catalyst composition, method of preparation, inlet feed conditions and temperature. In these experiments, two type of catalysts were studied: i) nanoparticles of Pt occluded in Al2O3 or CeO2-Al2O3 matrix containing 1.5 % of Pt where two different methods to incorporate the cerium were used and ii) conventional Pt supported catalysts containing 0.3 and 1 % of Pt on Al2O3 or with addition of 6 or 12 % of ceria. For catalysts based on nanoparticles, XAFS spectra were acquired at Pt L3-edge and Ce K and L3-edge under reduction and water gas shift (WGS) reaction conditions. The XAFS results reveal, after the reduction, the presence of Pt nanoparticles with similar coordination numbers (NPt-Pt), about 6, and similar Pt-Pt distances, about 2.75  0.01 Å. The catalyst activity for WGS and the strength of interaction between the metal and the support are related with cerium oxide structure revealed by XAFS analysis at Ce K and L3 edges. In situ infrared spectroscopy under WGS conditions revealed the presence of formates on the catalyst surface and that they are probably spectators for the reaction. It was possible to observe that these catalysts changes according to the atmosphere and temperature. Thus, it was possible to demonstrate, using the pre-formed nanoparticles that several parameters affect the catalyst behavior like: the metallic and the oxide particle size, the contact between them and what is exposed on the surface. For the conventional catalysts, the addition of ceria on 03PtAl sample enhances Pt oxidation, reflecting in a larger Pt-O coordination number for this sample. After reduction, 03PtAl resulted in larger Pt particles compared to the 12Ce03PtAl. For Ce-containing samples, in addition to the Pt-Pt contribution, a Pt-O contribution had to be considered to fit the spectra. This Pt-O increases proportionally to the cerium amount demonstrating that Pt clusters are anchored on support through a Pt-O bond. The Pt structure changes depends on the temperature, support nature and reactants composition, demonstrating that the catalytic properties requires the use of in situ characterization techniques.
Estudo da influência do preenchimento de alvéolos em lajes alveolares submetidas à força cortante
(Universidade Federal de São Carlos, 2014-04-28) Pinheiro, Gregory Lee; Almeida Filho, Fernando Menezes de; https://lattes.cnpq.br/0447825383222965; https://lattes.cnpq.br/3917156804189914
The use of precast elements has become crescent in Brazil, due to the need of haste during production as well as while assembling the structures. Bearing in mind a quick assembly and the competitive price for this kind of frame, precast elements have been growing and spreading in this field throughout the country. There is something special about demanding hollow core slabs, in virtue of their own low weight, in face of the empty spaces generated by the hollows and a better use of materials because of pretension technique, making it economically feasible. The National Technical Code ABNT NBR 9062, which deals with precast concrete structures, shows no more specific criteria as far as hollow core slabs are concerned, but on the other hand the 2011 review in force to ABNT NBR 14861 which covers precast hollow core slabs brings about relevant aspects such as the method used to check the capacity of shear strength on precast hollow core slabs, both with and without concrete structural cover, and furthermore with and without hollow fillings. Considering the reduced amount of national research on this topic, this study aims to develop and perform techniques in different ways of filling the hollows and the slabs and how they behave when exposed to shear strength tests. As a consequence to the manufacturing process of such type of slab and the hollow- filling method, failure in the idealized filling, in virtue of each material own behavior and inappropriate technique are commonly found.