Viabilidade econômica, desempenho e características de carcaça de garrotes em confinamento alimentados com dietas contendo silagem de capins tanzânia ou marandu ou silagem de milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Com o olhar nos professores: Desafios para o enfrentamento das realidades escolares

A escola tem sido crescentemente focalizada, não só no Brasil, mas em outros países, constituindo importante fonte para a compreensão das realidades vividas e sofridas pela grande maioria das populações mais privilegiadas econômica, social e culturalmente. A bibliografia produzida pelos autores de tais estudos denuncia, de maneira contundente, a baixa qualidade educacional em vários países, expressa por problemas como indisciplina na sala de aula, precárias condições para o trabalho educativo, despreparo dos professores para realizar adequadamente seu trabalho, baixo status profissional e baixa remuneração, agravados no Brasil pelos alarmantes índices de evasão e repetência. Com o olhar nos professores, como comprometimento político e preocupação de pesquisa, desde o ano de 1984, nossos estudos permitem dizer que esse quadro de problemas não constitui um insucesso generalizado, mas representa, sobretudo, desafios a enfrentar.

Origens dos instrumentos de formação da política comercial norte-americana

L'objectif de cet article est de montrer l'existence de traces historiques permettant de lier les concepts de libre-échange et protectionnisme, tous les deux employés dans la politique de commerce extérieur des Etats-Unis. Parallèlement, on cherche à souligner l'importance de la législation et des principes formulés dans ce pays et leur rôle explicatif concernant les motivations de la structure du commerce international après 1945. Ce rôle a en effet contribué à qu'on puisse mieux comprendre les tournées de négociations du GATT (General Agreement on Tariffs and Trade) jusqu'à la création de l'OMC (Organisation Mondiale du Commerce), en 1995. on traite également des raisons pour lesquelles le commerce international aux Etats-Unis est non seulement une question d'Etat mais encore une question de la société.

Avaliação da produção de leite e contagem de células somáticas em bovinos leiteiros suplementads com Saccharomyces cerevisiae como fonte de zinco orgânico

The aim of the evaluation of milk production and somatic cell count of dairy cow supplemented with Saccharomyces cerevisiae as a source of organic zinc for 180 days, 25 Holstein cows were selected, randomly chosen from a flock of 189 lactating cows. The animals were distributed in two groups, namely group 1 (G1) which holded 10 cows supplemented and group 2 (G2) with 15 animals without supplementation. The production of milk was measured by the control official milkman of the Assocition Paranaense of Creators of Bovine of the Holstein in seven moments during the 180 days. The samples of milk were collected of each animal, being submitted to the electronic counting of somatic cells. The results demonstrate that the supplemented of organic zinc didn't alter the production of milk, however it was capable to maintain low the counting of somatic cells. The data of the present work suggest that to use supplemented of organic zinc in the diet of cows milk, increase the quality of the produced milk and consequently the remuneration for the producer.

Custo Leite para Windows: Software de Controle de Custos para a Pecuária Leiteira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de NaCl no suplemento como alternativa para viabilizar o sistema de alimentação de bezerros em creep-feeding

Thirty two Canchim suckling calves, maintained on rotational grazing system of Brachiaria brizantha cv. Marandu, were divided in three groups corresponding to three evaluated treatments: control (without creep-feeding); SAL5 (addition of 5% of NaCl to concentrate fed in creep-feeding); and SAL10 (addition of 10% of NaCl to concentrate fed in creep-feeding). Feeding in a creep-feeding system lasted 90 days, divided in three subperiods of 30 days. The body weight gain was greater in the subperiods 1 and 2 for SAL10 and SAL5 treatments, respectively. There were no differences in the third subperiod and, in the overall period, the SAL10 treatment (0.91 kg.animal-1.day-1) was better than control treatment (0.81 kg,animal-1.day-1). The monthly remuneration provided by the treatments SAL5 e SAL10 related to the control group were-12.5 and 6.0%, respectively. The body weight differentials at weaning, compared to the control group, for creep-feeding provide a monthly net profit of 0, 0.6, 1.2, and 6.0% should be 10.8, 11.0, 11.2, and 12.8 kg.animal-1 for SAL5 and 7.6, 7.7, 7.8, and 9.0 kg.animal-1 for SAL10. It was concluded that the limited supplement intake in creep-feeding was necessary to obtain economic viability.

Spinning reserve opportunity cost in hydroelectric plants

Starting from the deregulated process of the Electric Sector, there was the need to attribute responsibilities to several agents and to elaborate appropriate forms of remuneration of the services rendered by the same. One of the services of great importance within this new electric sector is the Ancillary Services. Among the various types of Ancillary Services, Spinning Reserve is a service necessary for maintaining the integrity of the transmission system from either generation interruptions or load variations. This paper uses the application of the Economic Dispatch theory with the objective of quantifies the availability of Spinning Reserve supply in hydroelectric plants. The proposed methodology utilizes the generating units as well as their efficiencies so as to attend the total demand with the minimum water discharge. The proposed methodology was tested through the data provided by the Água Vermelha Hydroelectric Power Plant. These tests permitted the opportunity cost valuation to the Spinning Reserve supply in hydroelectric plants. © 2005 IEEE.

A preliminary physicochemical, exergetic and economic study of hydrogen production utilizing glycerol

This work has as objective to demonstrate technical and economic viability of hydrogen production utilizing glycerol. The volume of this substance, which was initially produced by synthetic ways (from oil-derived products), has increased dramatically due mainly to biodiesel production through transesterification process which has glycerol as main residue. The surplus amount of glycerol has been generally utilized to feed poultry or as fuel in boilers, beyond other applications such as production of soaps, chemical products for food industry, explosives, and others. The difficulty to allocate this additional amount of glycerol has become it in an enormous environment problem, in contrary to the objective of biodiesel chain, which is to diminish environmental impact substituting oil and its derivatives, which release more emissions than biofuels, do not contribute to CO2-cycle and are not renewable sources. Beyond to utilize glycerol in combustion processes, this material could be utilized for hydrogen production. However, a small quantity of works (theoretical and experimental) and reports concerning this theme could be encountered. Firstly, the produced glycerol must be purified since non-reacted amounts of materials, inclusively catalysts, contribute to deactivate catalysts utilized in hydrogen production processes. The volume of non-reacted reactants and non-utilized catalysts during transesterification process could be reutilized. Various technologies of thermochemical generation of hydrogen that utilizes glycerol (and other fuels) were evaluated and the greatest performances and their conditions are encountered as soon as the most efficient technology of hydrogen production. Firstly, a physicochemical analysis must be performed. This step has as objective to evaluate the necessary amount of reactants to produce a determined volume of hydrogen and determine thermodynamic conditions (such as temperature and pressure) where the major performances of hydrogen production could be encountered. The calculations are based on the process where advance degrees are found and hence, fractions of products (especially hydrogen, however, CO2, CO, CH4 and solid carbon could be also encountered) are calculated. To produce 1 Nm3/h of gaseous hydrogen (necessary for a PEMFC - Proton Exchange Membrane Fuel Cell - containing an electric efficiency of about 40%, to generate 1 kWh), 0,558 kg/h of glycerol is necessary in global steam reforming, 0,978 kg/h of glycerol in partial oxidation and cracking processes, and 0,782 kg/h of glycerol in autothermal reforming process. The dry reforming process could not be performed to produce hydrogen utilizing glycerol, in contrary to the utilization of methane, ethanol, and other hydrocarbons. In this study, steam reforming process was preferred due mainly to higher efficiencies of production and the need of minor amount of glycerol as cited above. In the global steam reforming of glycerine, for one mole of glycerol, three moles of water are necessary to produce three moles of CO2 and seven moles of H2. The response reactions process was utilized to predict steam reforming process more accurately. In this mean, the production of solid carbon, CO, and CH4, beyond CO2 and hydrogen was predicted. However, traces of acetaldehyde (C2H2), ethylene (C2H4), ethylene glycol, acetone, and others were encountered in some experimental studies. The rates of determined products obviously depend on the adopted catalysts (and its physical and chemical properties) and thermodynamic conditions of hydrogen production. Eight reactions of steam reforming and cracking were predicted considering only the determined products. In the case of steam reforming at 600°C, the advance degree of this reactor could attain its maximum value, i.e., overall volume of reactants could be obtained whether this reaction is maintained at 1 atm. As soon as temperature of this reaction increases the advance degree also increase, in contrary to the pressure, where advance degree decrease as soon as pressure increase. The fact of temperature of reforming is relatively small, lower costs of installation could be attained, especially cheaper thermocouples and smaller amount of thermo insulators and materials for its assembling. Utilizing the response reactions process in steam reforming, the predicted volumes of products, for the production of 1 Nm3/h of H2 and thermodynamic conditions as cited previously, were 0,264 kg/h of CO (13% of molar fraction of reaction products), 0,038 kg/h of CH4 (3% of molar fraction), 0,028 kg/h of C (3% of molar fraction), and 0,623 kg/h of CO2 (20% of molar fraction). Through process of water-gas shift reactions (WGSR) an additional amount of hydrogen could be produced utilizing mainly the volumes of produced CO and CH4. The overall results (steam reforming plus WGSR) could be similar to global steam reforming. An attention must to be taking into account due to the possibility to produce an additional amount of CH4 (through methanation process) and solid carbon (through Boudouard process). The production of solid carbon must to be avoided because this reactant diminishes (filling the pores) and even deactivate active area of catalysts. To avoid solid carbon production, an additional amount of water is suggested. This method could be also utilized to diminish the volume of CO (through WGSR process) since this product is prejudicial for the activity of low temperature fuel cells (such as PEMFC). In some works, more three or even six moles of water are suggested. A net energy balance of studied hydrogen production processes (at 1 atm only) was developed. In this balance, low heat value of reactant and products and utilized energy for the process (heat supply) were cited. In the case of steam reforming utilizing response reactions, global steam reforming, and cracking processes, the maximum net energy was detected at 700°C. Partial oxidation and autothermal reforming obtained negative net energy in all cited temperatures despite to be exothermic reactions. For global steam reforming, the major value was 114 kJ/h. In the case of steam reforming, the highest value of net energy was detected in this temperature (-170 kJ/h). The major values were detected in the cracking process (up to 2586 kJ/h). The exergetic analysis has as objective, associated with physicochemical analysis, to determine conditions where reactions could be performed at higher efficiencies with lower losses. This study was performed through calculations of exergetic and rational efficiencies, and irreversibilities. In this analysis, as in the previously performed physicochemical analysis, conditions such as temperature of 600°C and pressure of 1 atm for global steam reforming process were suggested due to lower irreversibility and higher efficiencies. Subsequently, higher irreversibilities and lower efficiencies were detected in autothermal reforming, partial oxidation and cracking process. Comparing global reaction of steam reforming with more-accurate steam reforming, it was verified that efficiencies were diminished and irreversibilities were increased. These results could be altered with introduction of WGSR process. An economic analysis could be performed to evaluate the cost of generated hydrogen and determine means to diminish the costs. This analysis suggests an annual period of operation between 5000-7000 hours, interest rates of up to 20% per annum (considering Brazilian conditions), and pay-back of up to 20 years. Another considerations must to be take into account such as tariffs of utilized glycerol and electricity (to be utilized as heat source and (or) for own process as pumps, lamps, valves, and other devices), installation (estimated as US$ 15.000 for a plant of 1 Nm3/h) and maintenance cost. The adoption of emission trading schemes such as carbon credits could be performed since this is a process with potential of mitigates environment impact. Not considering credit carbons, the minor cost of calculated H2 was 0,16288 US$/kWh if glycerol is also utilized as heat sources and 0,17677 US$/kWh if electricity is utilized as heat sources. The range of considered tariff of glycerol was 0-0,1 US$/kWh (taking as basis LHV of H2) and the tariff of electricity is US$ 0,0867 US$/kWh, with demand cost of 12,49 US$/kW. The costs of electricity were obtained by Companhia Bandeirante, localized in São Paulo State. The differences among costs of hydrogen production utilizing glycerol and electricity as heat source was in a range between 0,3-5,8%. This technology in this moment is not mature. However, it allows the employment generation with the additional utilization of glycerol, especially with plants associated with biodiesel plants. The produced hydrogen and electricity could be utilized in own process, increasing its final performance.

Valores Referenciais para Procedimentos Odontológicos (VRPO) em Ortodontia

Introduction: The cost of orthodontic treatment is a very important issue. The aim of this study was to analyze the current Indicative Values for Dental Procedures (IVDP) for orthodontic procedures. Methods: Laws, dental entities papers and scientific literature were utilized. Results: Laws are too general and only offer abstract parameters when define remunerations. Current IVDP vary in the same State, according to the consultant entity. Dental entities interpret that general clinicians can practice Corrective Orthodontics, but new scientific studies begin to question this understanding. The Brazilian Association of Orthodontics and Dentofacial Orthopedics (ABOR) suggests that IVDP for orthodontic specialty must be formulated. Conclusion: Current IVDP are not standardized and are below the correct values for orthodontic procedures, because they are the mean of general clinicians and orthodontists remunerations; and ABOR is legally and ethically supported to claim specific IVDP for orthodontic specialty.

Estudo econômico das diferentes formas de transporte de vinhaça em fertirrigação na cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise termodinâmica e termoeconômica do aproveitamento do gás natural em sistemas de cogeração de energia de usinas de açúcar e álcool

Pós-graduação em Engenharia Mecânica - FEIS

Reforma educacional neoliberal: uma análise política da concessão de bônus-mérto do governo José Serra (2007-2010) aos professores da rede estadual paulista

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A eficiência e a eficácia das normas antidumping na OMC e suas repercussões no direito concorrencial brasileiro

Pós-graduação em Direito - FCHS

O impacto da qualificação da mão-de-obra no desempenho comercial do Brasil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Criando novos tabuleiros para o jogo Tri-Hex e sua validação didático-pedagógica na formação continuada de professores de matemática: uma contribuição para a geometria das séries finais do ensino fundamental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)