Managing the dominant follicle in lactating dairy cows

Reproductive efficiency is not optimal in high-producing dairy cows. Although many aspects of ovarian follicular growth in cows are similar to those observed in heifers, there are numerous specific differences in follicular development that may be linked with changes in reproductive physiology in high-producing lactating dairy cows. These include: I) reduced circulating estradiol (E2) concentrations near estrus, 2) ovulation of follicles that are larger than the optimal size, 3) increased double ovulation and twinning, and 4) increased incidence of anovulation with a distinctive pattern of follicle growth in anovular dairy cows. The first three changes become more dramatic as milk production increases, although anovulation has not generally been associated with level of milk production. To overcome reproductive inefficiencies in dairy cows, reproductive management programs have been developed to synchronize ovulation and enable the use of timed AI in lactating dairy cows. Effective regulation of the CL, follicles, and hormonal environment during each part of the protocol is critical for optimizing these programs. This review discusses the distinct aspects of follicular development in lactating dairy cows and the methodologies that have been utilized in the past two decades in order to manage the dominant follicle during synchronization of ovulation and timed AI programs. (C) 2011 Published by Elsevier B.V.

Modelo AC para el despacho combinado de contratos bilaterales y bolsa de energía considerando restricciones de seguridad

Reliability is a key aspect in power system design and planning. Maintaining a reliable power system is a very important issue for their design and operation. Under the new competitive framework of the electricity sector, power systems find ever more and more strained to operate near their limits. Under this new scenario, it is crucial for the system operator to use tools that facilitate an energy dispatch that minimizes possible power cuts. This paper presents a mathematical model to calculate an energy dispatch that considers security constraints (single contingencies in transmission lines and transformers). The model involves pool markets and fixed bilateral contracts. Traditional methodologies that include security constraints are usually based in multistage dispatch processes. In this case, we propose a single-stage model that avoids the economic inefficiencies which result when conventional multi-stage dispatch approaches are applied. The proposed model includes an AC representation of the transport system and allows calculating the cost overruns incurred in due to reliability restrictions. We found that complying with fixed bilateral contracts, when they go above certain levels, might lead to congestion problems in transmission lines.

Subsídios para avaliação do ciclo de vida de modo simplificada da produção agrícola de milho por meio de um estudo de caso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Procedimentos para análise de lucratividade de produtos no setor de autopeças metálicas

In a globalized world, organizations face an increasingly dynamic, innovative and competitive environment, so that this condition requires continuous adaptation to market developments. Intense competition requires organizations to further improve their performance, making productive efficiency a key factor for survival. A methodology that has added value to the product through a reconfiguration of the production method is the implementation of a management philosophy called Lean Six Sigma. The main objective of this work is, in the light of the Lean Six Sigma philosophy, intervene in a critical-collaborative way to develop procedures for analyzing the profitability of products in a company specializing in steel processing. To achieve this goal, were applied the method of action-research to intervene in a group of professionals for the study of the profitability of products in a auto parts industry. The interaction of practical and theoretical knowledge provided by the action-research allowed the business program was enhanced. The procedures proposed in this study were able to identify the current profitability of the product, the main causes of inefficiency and productive for solutions to reduce production inefficiencies, when the productive systems planned and actual production system were compared. The results indicate that current profitability of -3%, while the parameter provided during budget was 10%. Thus, it is concluded that the low profitability of the products may compromise the company's financial results and affect their competitiveness in the market. To address this problem, the Lean Six Sigma presents itself as a versatile and high applicability philosophy, providing relevant results for characterization and troubleshooting. It was also observed that the evidence presented in this paper can be adapted to other companies in the metal auto parts segment to identify and recover the profitability of products

Estudo das principais políticas para melhoria da eficiência energética no setor elétrico

This paper aims at comparing the national and international incentive policies in energy efficiency investment and presenting the main trends, measures adopted and economical and environmental results obtained, as well as possible improvements and expansions of these programs. This analysis is justified by the current moment, not only of the Brazilian Power Systems (SEB) but also of the global power systems with the constant increase of demand and depletion of natural resources implying in a need of a better use of them and of the power they generate, which directly affects the losses on the generation, transmission, distribution and consumption of energy, in addition to reducing the impacts on the environment. At last but not least, through this study it was possible to gleam not only at new possible ways for these programs, but also failures and inefficiencies that can be improved in the measures currently being used

Fuzzy rule-based system for evaluation of uncertainty transaction in cassava chain

A fuzzy ruled-based system was developed in this study and resulted in an index indicating the level of uncertainty related to commercial transactions between cassava growers and their dealers. The fuzzy system was developed based on Transaction Cost Economics approach. The fuzzy system was developed from input variables regarding information sharing between grower and dealer on “Demand/purchase Forecasting”, “Production Forecasting” and “Production Innovation”. The output variable is the level of uncertainty regarding the transaction between seller and buyer agent, which may serve as a system for detecting inefficiencies. Evidences from 27 cassava growers registered in the Regional Development Offices of Tupa and Assis, São Paulo, Brazil, and 48 of their dealers supported the development of the system. The mathematical model indicated that 55% of the growers present a Very High level of uncertainty, 33% present Medium or High. The others present Low or Very Low level of uncertainty. From the model, simulations of external interferences can be implemented in order to improve the degree of uncertainty and, thus, lower transaction costs.

Modelo de leilão de energia multiperíodo com representação linearizada da transmissão e da coordenação com o médio prazo para sistemas hidrotérmicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)