Metodología multiobjetivo aplicada a análisis de datos

En este trabajo, se realiza una presentación unificada de la Programación Multiobjetivo, describiendo y relacionando los distintos conceptos de solución y exponiendo las distintas técnicas de solución. Se formula el problema multiobjetivo mediante una séxtupla, (O, V, X, f, Y, EP), que permite unificar los muy diversos problemas multiobjetivo que surgen en distintos ámbitos. O representa el conjunto de objetos inicial, V representa el conjunto de las características relevantes que se miden sobre los objetos, X es el espacio de alternativas, f representa la familia de objetivos, Y es el espacio de resultados y EP es la estructura de preferencias del decisor. A partir de esta formulación, se realiza un amplio estudio de los distintos problemas multiobjetivo. Además, se aplica la metodología multiobjetivo a dos problemas concretos de gran interés práctico. En primer lugar, se aborda el problema de seleccionar el mejor tratamiento, cuando sobre las unidades experimentales, elegidas de forma aleatoria, se observan varias variables respuesta. Se consideran Modelos Discretos, Modelos Continuos Paramétricos y Modelos No Paramétricos. El último capítulo del trabajo, se dedica al estudio del problema multiobjetivo que se presenta cuando se desea representar, un conjunto finito de objetos, sobre la recta real, de forma que se refleje, lo más fielmente posible, la desemejanza de cada par de objetos. En el caso de que la desemejanza cumpla la propiedad de ser naturalmente ordenable, se ha diseñado y programado, un algoritmo, en tiempo polinomial, que obtiene la solución óptima del problema...

Evolution of specific antibodies and proviral DNA in milk of small ruminants infected by small ruminant lentivirus

The diagnosis of Small Ruminant Lentivirus (SRLV) is based on clinical signs, pathological lesions and laboratory testing. No standard reference test for the diagnosis of maedi visna has been validated up to the present, and it is puzzling that tests which detect antibodies against the virus and tests which detect the proviral genome may render opposite results. The aim of this study was to evaluate the presence in milk throughout a lactation period of specific antibodies by ELISA and of SRLV proviral DNA by a PCR of the highly conserved pol region. A six-month study was conducted with the milk of 28 ewes and 31 goats intensively reared. The percentage of animals with antibodies against SRLV increased throughout the study period. Seroprevalence in sheep was 28% at the beginning of the study and by the end it had increased up to 52.4%. In goats, initial seroprevalence of 5.6% increased to 16%. The percentage of PCR positive ewes was stable throughout the study period. Of the positive sheep, 21.4% were PCR-positive before antibodies could be detected and most of them became PCR-negative shortly after the first detection of antibodies. This might suggest that antibodies have a neutralizing effect. In addition, an equal percentage of sheep were always PCR-negative but either became ELISA-positive or was always ELISA-positive, which might support this hypothesis. On the other hand, the PCR results in goats did not follow any pattern and oscillated between 35.3% and 55.6% depending on the month. Most goats positive by PCR failed to develop antibodies in the 6 months tested. We may conclude that the infection and the antibody response to it follow a different trend in sheep and goats.