Solving the Short Term Hydrothermal Coordination Problem considers the resolution of both the Unit Commitment and the Economic Dispatch for thermal and hydraulic units. This problem is solved for several time horizons between a day and a week with a one-hour step. The traditional short-term scheduling problem of hydrothermal units, minimizing fuel cost during a time, does not include concerns due to emission pollution coming from the operation of thermal plants. In this work, environmental constraints are considered. Focusing on avoiding post-dispatch corrections, the transmission network is modeled with a high level of detail considering an AC power fow. These facts lead to a very complex optimization problem which is solved by using a novel decomposition approach based on Generalized Benders Decomposition and traditional, well-known optimization techniques. The approach presented in this work allows the decomposition of the whole problem in a quadratic mixed integer master problem, and in a separable non-linear subproblem. The former defnes the state and the active power dispatched by each unit whereas the latter determines the reactive power to meet the electrical constraints through a modified AC optimal power fow. Diferent variations of the developed methodology were evaluated in order to consider environmental constraints. These approaches were applied to a 9-bus test case and to a 87-bus real system.

Avaliou-se a técnica de imunofluorescência indireta (IFA) na detecção de anticorpos contra o vírus da imunodeficiência felina (FIV) numa pesquisa epidemiológica do FIV na Argentina. A IFA foi modificada e comparada com duas outras técnicas imunológicas: western blot (WB) e imunocromatografia em camadas (SI) com kit comercial e também com reação em cadeia de polimerase (PCR) para detecção do DNA proviral. A IFA mostrou ser um teste com alta sensibilidade e especificidade e poderá ser empregada como ferramenta útil em estudos epidemiológicos. A baixa porcentagem de reatividade não específica pode ser esclarecida com testes mais avançados ou usando métodos alternativos.

This study evaluated an indirect immunofluorescence assay (IFA) to detect feline immunodeficiency virus infection (FIV) antibody in a comprehensive epidemiological survey of FIV in Argentina. IFA modified in our laboratory, was compared with two other immunoassays, western blot (WB) and a sandwich immunochromatographic commercial kit (SI), and also with a direct polymerase chain reaction (PCR) method that detects proviral DNA. IFA showed to be a test with high sensitivity and specificity, and could be useful as a diagnostic tool in epidemiological studies. The presence of a low percentage of results with non-specific reactivity in the IFA could be resolved with further testing or use of an alternative method.

The aim of this work was to study the prevalence, the pathological findings as well as the etiology of rectal stricture in a farrow-to-finishing farm during two periods, 1996 and 1998-99. In the first period, over 660 necropsied pigs belonged to nursery, grower and fattener categories, monthly median percent was 7.5% with values higher than 10% in the summer months for all categories and in September and December for nursery and grower pigs, respectively. In the second period, 879 pigs were examined and rectal stricture accounted for 10.3% and rectal prolapse for 7.7% with an average age of 164.2±6.1 y 115.8±4.2 days, respectively. Affected pigs showed abdominal distension and poor growth. Gross findings were distended rectum, spiral colon and cecum usually with fibrinous peritonitis and pericarditis. The rectal stricture was found about 2.5 to 5 cm in craneal to the anus with 3 to 8 cm in lengh. Bacteriological studies carried out from selected samples were negative for a common swine gut pathogens. One hundred twenty two samples for aflatoxins and zearalenone and 36 for deoxynivalenol investigation of commodities by a competition ELISA test were performed. There was not a direct correlation between high incidence of rectal stricture and levels of zearalenone, even though on field situation, little is known about what happens when this mycotoxin is fed in low levels along the year, alone or in association with deoxynivalenol. It was concluded that rectal stricture is a condition that affects pig production. Their etiology appears multifactorial and mycotoxins, particularly zearalenone, seem to play an important role as a primary cause of rectal prolapse followed by rectal stricture as a sequel to untreated cases