Browsing by Issue Date, starting with "2005-03-03"

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Uma análise bayesiana para dados composicionais
(Universidade Federal de São Carlos, 2005-03-03)
Obage, Simone Cristina
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Achcar, Jorge Alberto
;
https://lattes.cnpq.br/3125027713681936
;
https://lattes.cnpq.br/4186813257353303
Compositional data are given by vectors of positive numbers with sum equals to one. These kinds of data are common in many applications, as in geology, biology, economy among many others. In this paper, we introduce a Bayesian analysis for compositional data considering additive log-ratio (ALR) and Box-Cox transformations assuming a mul- tivariate normal distribution for correlated errors. These results generalize some existing Bayesian approaches assuming uncorrelated errors. We also consider the use of expo- nential power distributions for uncorrelated errors considering additive log-ratio (ALR) transformation. We illustrate the proposed methodology considering a real data set.
PHOENIX: uma abordagem para reengenharia de software orientada a aspectos
(Universidade Federal de São Carlos, 2005-03-03)
Garcia, Vinícius Cardoso
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Prado, Antonio Francisco do
;
https://lattes.cnpq.br/2668568143800755
The continuous technological evolution makes many systems become obsolete due to changes in hardware and software platforms, although the fact that they attend their requirements and that they are stable. Software reengineering, integrated with modern techniques of reverse and forward engineering, can be the solution to reconstruct these systems reusing the knowledge embedded in the code and the available documentation. Even when current reengineering techniques are used, some problems regarding the legibility of the code are found in the reconstructed systems. Recently developed systems making use of modern techniques for object oriented analysis, design and implementation using software patterns also have these problems. Thus, motivated by the ideas of a better solution to improve systems codes legibility that have already been built, we intend to investigate an approach to rebuild such systems, obtaining their project and code restructured in a more readable and organized way. The approach combines reverse engineering techniques, component-based modeling, software transformation, and Aspect-Oriented Programming to reconstruct software systems from legacy code and available documentation. The code and the documentation of the reconstructed system are structured according to Aspect-Orientation, which facilitates its maintenance and continuous evolution and complies with new hardware and software technologies. The main mechanisms for the execution of the approach are a Transformational System and a CASE tool, which automates most of the software engineer tasks.
Proposta de estrutura e de método para coordenação da qualidade em cadeias de produção agroalimentares.
(Universidade Federal de São Carlos, 2005-03-03)
Borrás, Miguel Angel Aires
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Toledo, José Carlos de
;
https://lattes.cnpq.br/9421627326330417
The questions on food quality and food safety are main problems to elaborate healthy agri-food products from ecological process. Those factors, associated with the increasing agri-food sector s competitiveness are basics to conquest new competitive levels by agri-food supply chains (ASC). It follows that is primordial that ACS achieves the assurance of the quality and safety for its products. This can be obtained with the integrated management of quality in the production stages performed along all chain. On this thesis, the type of management which reaches all ACS is called quality coordination. The thesis proposes a structure (Structure for Quality Coordination SQC) and a method (Method for Quality Coordination MQC) which can help the ACS to coordinate the quality into its segments. Thus, the research is based on wide bibliography revision that discusses theoretical concepts on agri-food chain, supply chain, quality management, agri-food coordination and change theories. This revision generated: a) the quality coordination concept; b) the proposal of the SQC and MQC; and c) the SQC/MCQ Implantation Procedure (SMIP). The SQC is composed of the own ACS with its segments and agents, coordinating agent, quality product and quality management requirements and for the MQC. The MQC is composed of eight modules which claims: a) to identify the Demanded Quality (DQ) and deploy it in product and management requirements; b) to follow and evaluate the quality management practices and ACS performance indicators; and c) to propose and control improvement plans. Besides, the SQC and the MQC was evaluated in workshop accomplished with representatives of alcohol and sugar factories and rural producers. A brief illustration of the SMIP and SQC/MQC using in the Brazilian apple ACS is presented too. On this illustration is discussed the financial and technical viability of the SCQ/MQC. Therefore with a wide theoretical background is possible conclude that the SCQ and MQC can contribute to assure the quality and safety of agri-food products, improving the ACS competitiveness.
Sobre o modelo de supercondutividade de Ginzburg- Landau com efeito magnético em domínios delgados
(Universidade Federal de São Carlos, 2005-03-04)
Pereira, Jamil Viana
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Nascimento, Arnaldo Simal do
;
https://lattes.cnpq.br/6609243657130387
;
https://lattes.cnpq.br/1641850650875934
Desempenho de criança de 7 a 10 anos em diferentes tarefas de controle postural
(Universidade Federal de São Carlos, 2005-03-04)
Kishi, Marcos Seizo
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Tudella, Eloisa
;
https://lattes.cnpq.br/3207258034860219
;
https://lattes.cnpq.br/2333440373816942
The aim of this study was to describe the effect of different tasks on the postural control of children aged between 7 and10 years old. Twenty-one children, divided into two age groups of 7-8 and 9-10 years old, participated in the study by performing 5 tests from the Balance Master System. The purpose of the first test was to verify the ratio of weight bearing to the levels of articular stress conferred by different degrees of knees flexion, and, according to ANOVA test, there were no differences either between the groups or among the conditions. Both the second and the fifth tests aimed to verify the influence of sensory cues on the postural control quantified by the sway speed; the former provided somatosensory and visual cues, and the latter, vestibular and visual cues. Kruskal-Wallis statistic test was applied to these two tests, and no differences were found between the groups. However, the groups showed distinct behaviors in relation to the conditions. The second test indicated that the alteration in somatosensory input resulted in maximal instability of the postural control, while the fifth one verified maximal instability when vestibular input was altered. The aim of the third test was to identify the response of the control motor components during the performance of tasks that involve intentional movement of the center of body mass toward the target. The group of 7-8-year-old children showed better performances in Endpoint Excursion (EPE) and Movement Velocity (MV), and it seems to be related to cognitive aspects of the task. The forth test aimed to relate the variables of gait to the maintenance of the stability following its achievement, and, although no differences were found between the groups, it was verified positive correlations between anteroposterior body sway and step width as well as progression velocity. Regarding the postural control, it is possible to conclude that the age influenced the variables EPE and MV, since the age group of 7-8 years old showed better performances. In addition, postural as well as motor control of the children was influenced by sensory cues of the tasks.
Extensões de soluções homogêneas de uma classe de operadores diferenciais parciais reais de ordem um
(Universidade Federal de São Carlos, 2005-03-04)
Gabriel, Camila Pires Cremasco
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Santos Filho, José Ruidival Soares dos
;
https://lattes.cnpq.br/6112529384454347
Elaboração, aplicação e avaliação de um Programa de Ensino de Ginástica Acrobática sob a ótica da inclusão
(Universidade Federal de São Carlos, 2005-03-04)
Borella, Douglas Roberto
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Denari, Fátima Elisabeth
;
https://lattes.cnpq.br/5575213011914394
The search for a society more joust represents a great challenge. As for the paradigm of the social inclusion, the necessary school to participate changed ding itself into a space where education for given it if comes back toward all the people. The inclusion of pupils with educational necessities special comes being white of many studies and quarrels. One of the concerns is to know until where this can give certain. Being this the present study it had for objective to evaluate the effect of a program of education of Acrobatic Gymnastics in a group of pupils with light and moderate mental characterized necessities educational special as deficient registered in a municipal school that takes care of to pupils with educational necessities special and pupils of common education, both with age between 08 and 10 years. The procedure consisted of the following stages: 1) elaboration of one Program of education of Acrobatic Gymnastics for lessons of Physical Education; 2) application and evaluation of the Program of Acrobatic Gymnastics; 3) evaluation and reevaluation of the affective-social data. The data had been analyzed on the basis of the comparisons of the repertoires of the pupils before and after the application of the education program. For way of this salient it effectiveness of the Acrobatic Gymnastics for the development of this population, pointing referring subsidies with respect to the systematization of knowledge and procedures to the area of Suitable the Physical Education, aiming at to accumulate of stocks the best performance of the important aspects for the development and learning of the pupil. With this program we aim at the inclusion of our pupils in the scopes of the society and the school as well as its participation in events and activities together to the too much common citizens.
Inteligência competitiva a tecnologias do carbeto de silício para o setor de abrasivos
(Universidade Federal de São Carlos, 2005-03-04)
Morais, Túlio Lissandro Melo de
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Gregolin, José Angelo Rodrigues
;
https://lattes.cnpq.br/7842651773105125
Because the fact we don t have studies about Silicon Carbide ( SiC ) to abrasives in Brasil, this study sought to accomplish the SiC technological search in abrasives using Competitive Intelligence. The necessity to know the SiC application trends and threat in bonded abrasives in Brasil It was the decision detanier necessity showed by focal company. In addition, it was objective from focal company to know the market and technology about its and your national competition in SiC business. Using the Michael Porter analysis method, it could be observed that the national competitor from focal company has a bargain can biggest in many aspects in SiC chain. The changes involving anti-duping in EUA and Europe will must change the world SiC production scenario in these areas, affecting Brasil. After the intelligence cycle application and the Swot method use, it could be observed that synthetic diamond is one strong threat to SiC. Some abrasives tools already are suffering impact with this substitution of the SiC for the synthetic diamond, like to cutting wheels and grinding wheels and disks to marble, granite, stones and ceramics. To polish, it didn t verified that it will have big changes for the next years, therefore the superabrasives are getting space and it will must be monitored, like proposed in this study with a monitor system. The technological necessity of the sizing process innovation to SiC, to can be more efficiency to produce grains between 80 and 220 in ANSI and FEPA, it was detected because for these grains it won t happen synthetic diamond strong threat in the next years. The SiC micrograins production in the national market is one necessity. Actually it doesn t have enough availability and the actual national micrograins quality isn t so good. The production technology to offer to the market the micrograins in big quantities and with good quality, like humid sedimentation process with Elutriation is proposed and already the focal company has it.
Catalisadores Cu-, Co- ou Fe-ZSM-5 caracterização e avaliação na redução de NO a N2 com hidrocarbonetos na presença ou ausência de vapor de água
(Universidade Federal de São Carlos, 2005-03-04)
Fernandes, Juliana Esteves
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Urquieta-González, Ernesto Antonio
;
http://lattes.cnpq.br/2389975677904655
The minimization of the emissions of nitrogen oxides (NOx) in the atmosphere has been one of the great goals in the area of environmental protection. Among the possible processes to treat the NOx, the selective catalytic reduction of NO with hydrocarbons (SCR-HC) has presented important expectations. For this process, the metal/ZSM-5 type catalysts have appropriate levels of conversion in oxidative conditions. In this context, the aim of this work was to prepare Cu, Co and FeZSM-5 catalysts. The samples were characterized by XRD, DRS-UVVIS, FTIR, H2-TPR, SEM and tested in the reduction of NO to N2 with propane or methane in oxidative atmosphere in the presence or absence of water steam. The H2-TPR data showed that the cationic species present in the prepared Cu, Co and FeZSM-5 catalysts, after thermal activation, were mainly Cu2+ (Cuα 2+ e Cuβ 2+), Co2+ and Fe3+ cations located in charge compensation sites in the zeolite, respectively. From FTIR and DRS-UVVIS it was also possible identify oxide species, which were present in a lower content. In the reduction of NO to N2 in the absence of water steam, the CuZSM-5 catalysts showed higher levels of conversion of NO than those based in Co and Fe. However, the FeZSM-5 catalysts showed, in this condition, activity at lower temperatures. This behavior makes them potentially interesting to be applied for practical purposes. On the other hand, in the presence of water steam, it was verified a higher loss of activity of the CuZSM-5 catalyst, which was totally restored removing the water in the feed. For the Co and FeZSM-5 catalysts, the activity loss in the presence of water steam was partially recovered during time on stream.
Processamento e caracterização da liga Al93Fe3Cr2Ti2 solidificada rapidamente
(Universidade Federal de São Carlos, 2005-03-07)
Bonavina, Luiz Fernando
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Kiminami, Claudio Shyinti
;
https://lattes.cnpq.br/5443002033733395
;
https://lattes.cnpq.br/1415547884100471
The necessity to use materials presenting low density, high tensile strength and easy processing ability have led to the development of news materials and news processing techniques. More recently we can find in the literature, successful reports concerning the developing of bulk nanocrystalline composite alloys presenting a microstructure composed of Al + Quasicrystal + Al23Ti9 phases, obtained by extrusion of atomized powder. The goal of our work was to evaluate the perspective in obtaining bulk quasicrystalline composite, in centimeters scale, by spray deposition process. The Al93Fe3Cr2Ti2 alloy was processed by spray forming using nitrogen as atomizer gas onto a cooper substrate. To understand the influence of the cooling rate on the microstructure, the alloy was cast into an edge shaped cooper mould and the cooling rate has been estimated by using MAGMASOFT software. The samples were then characterized by the use of scanning (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Vickers microhardness measurements and also compressive tests at room temperature. The desired microstructure composed of quasicrystalline particles embedded in Al matrix has been formed only under the higher cooling rate: i) in 90µm thick region of the edge mould sample, where a cooling rate of 105 K/s has been estimated; ii) in the thinner (10mm) region of the spray formed deposit corresponding the peripherical area of the atomization cone. The results indicate that the spray forming is a promising process to produce bulk quasicrystalline composite alloys. However, to fully explore this potential the gas-metal ratio must be higher than that used in the present work, to maintain all the deposit at the same condition as observed at the peripherical region of the atomization cone.
Pesquisas sobre o negro e a educação no Brasil: uma análise de suas concepções e propostas.
(Universidade Federal de São Carlos, 2005-03-07)
Ribeiro, Cristiane Maria
;
Barbosa, Joaquim Gonçalves
This abstract aimed at exploring the education/pedagogical proposal of researches regarding the theme of blocks and education and understanding the extent of black understanding race relations and education that underline such a proposal. For this task 101 studies were analyzed, including masters dissertations, doctoral theses, and post-doctorate studies carried out in Brazil between the seventies and the first semester of 2004. In our study we present four paradigmatic moments in studies on blacks in Brazil. The first has its historical setting at the end of the XIX century and dawn of the XX and among its postulations are found assumptions concerning black inferiority , both cultural and biological. A second interpretation of blacks in Brazilian social thought saw its greatest expression in the thirties and forties of the XX century and primarily took for granted the assumed harmonic pattern in social relations. Another interpretation of race relations evolved the studies carried out by researchers of the São Paulo School (Escola Paulista) and their followers. Among their principal arguments is the assertion that the past pratice of slavery is largely responsible for the present situation of blacks in Brazil. We also put forth the interpretation lead Hasenbalg that presupposes the deliberate relegation of questions of black Brazilians to mere questions of class. At the same time we explore studies that point out increased appreciation of the unique aspects of the situation of black Brazilian referring to concepts of ethnic identity and ethnicity. The study´s data presents a survey of research on the theme of blacks and education in Brazil various aspects, such as: profile of researchers and studies, ideas and proposals/suggestions that recommend the necessary modifications to the Brazilian educational system in order to provide an education that respects ethno-cultural diversity.
Fenologia de Catasetum fimbriatum (Morren) Lindl. (Catasetinae, Orchidaceae) e sua polinização por abelhas Euglossini (Hymenoptera, Apidae) na região de São Carlos-SP, Brasil
(Universidade Federal de São Carlos, 2005-03-08)
Ferreira, Alessandro Wagner Coelho
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Lima, Maria Inês Salgueiro
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https://lattes.cnpq.br/2171993314203162
Catasetum fimbriatum is an epiphyte plant with a strong sexual dimorphism, witch can have inflorescences with male flowers, female flowers or mixed inflorescences. It can have also hermaphrodite flowers. In this work we studied twelve phenological events of this species, its main herbivores, visitors and the pollinator species. We used orchid populations of five locations at the central region of São Paulo state (Brazil), around São Carlos municipality. For the study of visitors/pollinator bees we used blooming plants and vanillin, eugenol and cineol traps. We trapped and stamped the bees with automotive color brilliant ink. The pollinator of C. fimbriatum is Eufriesea violascens. This orchid is also visited by E. truncata and E. cordata. E. violascens has the most specific interaction with the orchid, since, we met it in the field only when the major number of orchids were bloomed, other wise, Euglossa spp. could be seen for more time. C. fimbriatum has his development affected by the herbivores action, mainly by the larva of Riechia acraeoides (Lepidoptera). We registered 14 host species, the main are: Acrocomia aculeata, Cedrela fissilis, Gochnatia polymorpha e Anadenanthera falcata. A statistics analysis shows linear correlation to the following factors: pseudobulb diameter and male flowers number, pseudobulb diameter and plant larger height, plant larger height and male flowers number, male flowers number and fruits number, female flowers number and fruits number.
Estudo in vitro de cito e fototoxicidade das drogas nitroheterocíclicas Nitracrina e Quinifuryl
(Universidade Federal de São Carlos, 2005-03-09)
Rossa, Marcelo Muniz
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Araújo, Heloísa Sobreiro Selistre de
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https://lattes.cnpq.br/4065824911933203
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https://lattes.cnpq.br/1106059868787042
The cytotoxicity of two nitroheterocyclic compounds, Polish antitumor agent, Nitracrine and Russian antiseptic, Quinifuryl, towards three lines of cells were determined under normoxia conditions. Special emphasis has been placed on the comparisons of the drugs effects in highly tumorogenic, leukaemic P388 and K562 and non-tumorogenic, fibroblast cells NIH3T3. Both drugs showed significant cytotoxicity to all cell lines. Toxicity of both drugs toward murine leukaemia was substantially higher, compared to non-transformed murine fibroblasts. At the drug concentrations of 2 nmol/ml, it took 2-3 times less time to reach the LC50 with P388 compared to NIH3T3. Uptake of drugs by human erythroleukaemia cells was observed starting 10 min from the addition of the drug, while the LC50 values were achieved after 3 hr of incubation. This delay in cell killing may be due to the intracellular transformation of drugs required for cell killing. It was also investigated the cellular phototoxicity of both drugs towards murine leukaemia, fibroblast and human erythroleukaemia cells. The cytotoxicity of these drugs towards two lines of leukaemic cells and a line of non-transformed cells, was measured in comparison, on the dark and under illumination. Both drugs showed highly elevated cytotoxicity when illuminated with LC50 values 7-35 times lower after 1 h illumination compared to 1 h incubation of cells incubation with drug on the dark. Cytotoxicity of Nitracrine toward all cell lines studied exceeded that of Quinifuryl, both on the dark and under illumination, so that 10 times lower concentration of former drug was needed to reach the same toxicity as the latter. General toxic effect was calculated as a direct cell kill and a cell proliferation arrest. Micelles (PEG-2000-stearate) and small unilamellar liposomes (DSPC) were chosen as vehicles and cytotoxicity of free and immobilized drugs was studied. We show that both drugs are effectively immobilized and strongly retained by both micelles and unilamellar liposomes. Both drugs are highly toxic against all line cells, when is immobilized in liposomes DSPC. A protective effect of micelles against Nitracrine toxicity toward P388 cells was observed at low drug concentration (0.2 nmol/ml), but not at higher concentration (2 nmol/ml). Micelles also protected P388 cells against cytotoxicity of Quinifuryl.
Análise da eficiência energética da secagem de pastas em leito de jorro
(Universidade Federal de São Carlos, 2005-03-10)
Fernandes, Conceição Flores
;
Corrêa, Ronaldo Guimarães
One of the most intensive uses of energy in industry is due to drying. After drying, the dry material becomes easy to transport, to storage, and to conserve for a long period of time. In this context, the aim of this work was to analyze the energy efficiency of a Spouted Bed in the drying of pastes in order to establish optimal conditions of operation and to propose modifications in the process to improve its energy efficiency. To issue these analyses, a mathematical model was derived which includes mass balance equations and energy balance equations for both the dryer and the inlet gas heater. The drying rate was quantified by the difference between the content of water in the feed flow rate of paste and the content of water in the exit dry solid. The mathematical model was implemented using MatLab programming language. The results obtained in both steady and dynamic simulations were compared with experimental data, showing that the model represents the process quite well for the operational conditions considered. Simulations were accomplished to analyze the behavior of the energy efficiency from disturbances in the feed flow rate of paste ( e F ), in the feed flow rate of gas ( g V ), composed by air and vapor of water, and in the power supplied to the inlet gas heater ( Pot ). Pinch Analysis was also performed to the system, which suggested some modifications in the process in order to improve its energy efficiency. The energy efficiency was quantified by the ratio between the necessary energy to evaporate the water and the sum of the necessary energy to blow and heat the inlet gas. The simulations showed that the energy efficiency so far used is improved by increasing the feed flow rate of paste, by decreasing both the power supplied to the inlet gas heater and the power supplied to the blower. It was observed that the increase in the temperature of the feed flow rate of paste showed a small effect in the energy efficiency.
Extensão da ferramenta MVCASE com serviços remotos de armazenamento e busca de artefatos de software
(Universidade Federal de São Carlos, 2005-03-10)
Lucrédio, Daniel
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Prado, Antonio Francisco do
;
https://lattes.cnpq.br/2668568143800755
Software reuse aims to increase productivity and to decrease time-to-market, through work optimization and avoiding effort duplication. In this context, two areas arise: Software Components and Computer-Aided Software Engineering (CASE). The Component-Based Development approach aims to offer ways to build more reusable software. The use of CASE seeks to reduce effort, by delegating part of the tasks to be performed by the computer, and to improve quality, by helping the Software Engineer to perform some tasks. Combining the ideas of software components and CASE, this dissertation presents an extension of MVCASE tool, an academic tool developed in UFSCar - Federal University of São Carlos, with remote services for storage and search for software artifacts, aiming to improve productivity and to reduce time and costs in software development.
Estudo dos efeitos de colisões atômicas na dinâmica, nas propriedades estatíticas e no emaranhamento entre átomos aprisionados interagindo com a luz
(Universidade Federal de São Carlos, 2005-03-10)
França, Vivian Vanessa
;
Pratavieira, Gilberto Aparecido
In this work we consider a trapped Bose-Einstein Condensate interacting simultaneously with a high quality cavity quantized field and a classical undepleted laser field. Collisions between atoms are taken into account by a delta type contact potential. A linearized model is obtained which take into account simultaneous amplification of atomic and optical fields. We analyse the effects of atomic collisions on the system stability and statistical properties. Also is done a study of the degree of entanglement between atomic and optical fields.
Interação entre a Matéria de Vórtices e arranjos minimamente ordenados de defeitos de aspecto colunar em YBa2Cu3O7-δ
(Universidade Federal de São Carlos, 2005-03-10)
Nunes, Juliana Sens
;
Ortiz, Wilson Aires
;
https://lattes.cnpq.br/0241177338066307
In this work we have studied the interaction of Vortex Matter with columnar defects in YBa2Cu3O7-δ supercondutcting samples. In these samples prepared by a Solgel chemical route, the granularety is delicately controled so that the the average cross section of grains is reasonably constant and the penetration of magnetic flux lines is columnar-like. Using magnetic and transport measurements we have constructed the phase diagram of the studied sample, determinating the higher critical field, the irrevesibility line, and the line were the pinned vortices lose longitudinal coherence which we call H*(T). AC-susceptibility and 6-terminal transport measurements were used to determine H*(T). The results confirm that, above T* there is a break of longitudinal coherence and the vortices behave like "pancakes" according to Clem's model, whereas below T* the longitudinal coherence is maintained. The experimental line H*(T) was theoretically ajusted, confirming that it is a line of change from the three-dimensional coherence of the vortices, to an almost two-dimensional of the "pancakes". Due the existence of a variety of superconducting systems with columnar-like defects that also present the line H*(T), as for example Mg-deficient MgB2, it is useful to compare them with the hope that some type of universal behavior can be observed. The normalized magnetic phase diagram with data of YBa2Cu3O7-δ and MgB2 revealed the expected similarity between the two systems studied, due to microstructural similarities between both and not to any intrinsic characteristic of the superconducting materials, that are very different among themselves.
Efeito do teor de CeO2 em catalisadores de Pt/CeO2-Al2O3 para as reações de oxidação parcial e reforma do metano
(Universidade Federal de São Carlos, 2005-03-10)
Santos, Ana Cláudia Sousa Fonseca
;
Bueno, José Maria Corrêa
;
https://lattes.cnpq.br/0157452280626031
The effect of CeO2 loading in Pt/CeO2-Al2O3 catalysts was investigated. Pt catalysts supported on mixed CeO2-Al2O3 carriers with different CeO2 loading 1, 3, 6, 12, 20 wt.% were prepared by incipient wetness impregnation method. For all samples, the Pt content was about 1 wt.%. The catalysts were characterized by SBET, X-ray diffraction (XRD), temperature-programmed reduction (TPR), UVVis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), reaction of dehydrogenation of cyclohexane and oxygen storage capacity (OSC) measurements. SBET results showed that the ceria promoted the stabilization of the superficial area of the alumina in samples of CeO2-Al2O3 with low CeO2 content (≤ 6%). XRD showed the formation of nanocrystallites of ceria on alumina surface when the amount of CeO2 was higher than 6 wt.%. TPR patterns indicated that the presence of Pt promoted the reduction of CeO2 in lower temperature than what was observed for the CeO2-Al2O3 supports. The increase of CeO2 loading lead to an increment in the OSC. The results for the reactions of partial oxidation, steam reforming and autothermal reforming of methane revealed that the activity of Pt/CeO2-Al2O3 catalysts was dependent of the CeO2 loading. Pt catalyst with CeO2 loading higher than 12 wt.% exhibited the highest specific activity and stability for partial oxidation of methane. This high stability was attributed to a combination of the properties as the presence of the CeO2 fluorite structure and different OSC values. Although the superficial structure of Pt did not show a decisive role for the high stability of Pt/CeO2-Al2O3 catalysts with CeO2 loading higher than 12 wt.%, the different Pt morphologies can show different rates for methane activation resulting in a better performance of surface carbon removal and therefore making more Pt sites available to the reaction.
Contribuição citogenética à análise da biodiversidade em Astyanax fasciatus (Pisces, Characidae)
(Universidade Federal de São Carlos, 2005-03-10)
Pazza, Rubens
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Bertollo, Luiz Antonio Carlos
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https://lattes.cnpq.br/7069073110550804
Astyanax fasciatus is characterized as a cytogenetically diverse species. Sympatric and syntopic occurrence of distinct cytotypes corroborates the hypothesis that A. fasciatus might represent a species complex sharing a common denomination. In this work, specimens from three collection sites along Mogi-Guaçu River, on Southeastern Brazil, were examined: (1) close to headwaters (Ouro Fino MG), (2) in the mean river portion (Cachoeira de Emas, Pirassununga SP, characterized by the presence of a dam) and (3) close to river mouth at Pardo river (Barrinha SP). Two karyotypes bearing perfectly paired chromosomes, named standard cytotypes, were identified; one of them with 2n=46 and another one with 2n=48 chromosomes. The cytotype 2n = 48 was found in all collection sites, whereas the cytotype 2n = 46 was restricted to Barrinha and Cachoeira de Emas. In this latter locality, the cytotype 2n=46 was predominant, but variant karyotypical forms were also reported, bearing 2n=45 and 47 chromosomes, besides a structural variant with 2n=46. A variant with 2n=47 chromosomes was also found in Ouro Fino. The Ag-NORs and 18S and 5S rDNA sites showed a conserved distribution among cytotypes, as well as the constitutive heterochromatin, preferentially located at terminal region on the long arms of submetacentric, subtelocentric and acrocentric chromosomes and terminal region on short arms of a submetacentric pair. This latter region showed to be GC-rich after chromomycin A3 staining and it corresponds to the location of a Nucleolar Organizer Region. Sites bearing the satellite DNA As51 were detected at terminal region on the long arms of several chromosomes, distributed over 4 submetacentric pairs, 3 subtelocentric pairs and one acrocentric pair in the standard cytotype 2n=46, and over 3 submetacentric pairs, 4 subtelocentric pairs and one acrocentric pair in the standard cytotype 2n=48. The variant karyotypical forms also presented other chromosomes bearing such satellite DNA, remarkably at a large metacentric chromosome bearing a terminal site on the long arms (found in two variant karyotypes), two subtelocentric pairs bearing additional interstitial site (found in one variant karyotype), and one submetacentric pair bearing a subterminal site on the long arms (found in one variant karyotype). Data based on RAPD (Random Amplified Polymorphic DNA) were poorly informative to analyze the reported diversity, indicating a high number of migrants per generation among cytotypes. On the other hand, data from ISSR (Inter-Simple Sequence Repeats) showed a low structuring, mainly between two standard cytotypes from Barrinha, where a Nm value of 0,4301 was observed, with a genetic identity of 0,6862 and genetic distance of 0,3765. The values of genetic distance (0,3219) and genetic identity (0,7248) between cytotypes with 2n=48 from Barrinha and Ouro Fino also evidenced a slight differentiation, indicating that the dam at Cachoeiras de Emas is probably a barrier to gene flow among populations located upstream and downstream the dam. The obtained results with molecular markers do not discard the possibility of inbreeding among the cytotypes of A. fasciatus, as a source of the diversity found. Hypothetically, the standard cytotype with 2n=48 might be the resident form at Mogi- Guaçu River, while the cytotype with 2n=46 would represent an invasive form, showing recent divergence. Although the variant karyotypes present a karyotypical structure similar to the cytotype with 2n=46, there are evidences that chromosomes typical from the cytotype with 2n=48 have been incorporated, suggesting that such variants may be derived from viable crossings among standard cytotypes, and/or their offsprings, which share some homologies, as demonstrated by chromosomal markers. The presence of a higher number of As-51 sites in some variants reinforces their inbreeding origin. The As-51 sites, which showed to be specific for some variant forms, might be originated by complementary chromosomal rearrangements, propitious to new locations of this satellite DNA on karyotypes.
São Carlos nos jornais: representações e cotidiano 1889-1901.
(Universidade Federal de São Carlos, 2005-03-10)
Datrino, Renata Martinês
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Monsma, Karl Martin