Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n=8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement.
-It is important to evaluate the application of new technologies in the field of computational science to forest science. The goal of this study was to test a different kind of metaheuristic, namely Clonal Selection Algorithm, in a forest planning problem. In this problem, the total management area is 4.210 ha that is distributed in 120 stands in ages between 1 and 6 years and site indexes of 22 m to 31 m. The problem was modeled considering the maximization of the net present value subject to the constraints: annual harvested volume between 140,000 m 3 and 160,000 m 3 , harvest ages equal to 5, 6 or 7 years, and the impossibility of division of the management unity at harvest time. Different settings for Clonal Selection Algorithm were evaluated to include: varying selection, cloning, hypermutation, and replacement rates beyond the size of the initial population. A generation value equal to 100 was considered as a stopping criteria and 30 repetitions were performed for each setting. The results were compared to those obtained from integer linear programming and linear programming. The integer linear programming, considered to be the best solution, was obtained after 1 hour of processing. The best setting for Clonal Selection Algorithm was 80 individuals in the initial population and selection. Cloning, hypermutation, and replacement rates equal to 0.20, 0.80, 0.20 and 0.50, respectively, were found. The results obtained by Clonal Selection Algorithm were 1.69% better than the integer linear programming and 4.35% worse than the linear programming. It is possible to conclude that the presented metaheuristic can be used in the resolution of forest scheduling problems.Keywords: Operational research; Artificial intelligence; Artificial immunological system. METAHEURÍSTICA CLONAL SELECTION ALGORITHM PARA OTIMIZAÇÃO DO PLANEJAMENTO FLORESTALRESUMO -Dada a importância de se avaliar novas tecnologias para otimização do planejamento florestal, este trabalho objetivou introduzir a metaheurística Clonal Selection Algorithm na resolução de um problema de ordenamento da produção florestal. Considerou-se uma área manejada de tamanho igual a 4.210 ha, contendo 120 talhões com idades entre 1 e 6 anos e índice de sítio variando entre 22 m e 31 m. O problema foi modelado com o objetivo de se maximizar o valor presente líquido global do empreendimento e considerou como restrições uma demanda anual entre 140.000m 3 e 160.000 m 3 , colheita apenas nas idades de 5, 6 e 7 anos e a imposição de não fracionamento dos talhões no momento do corte. Foram avaliados diferentes configurações da metaheurística Clonal Selection Algorithm, variando-se as taxas de seleção, clonagem, hipermutação e substituição, além do tamanho da população inicial. Considerou-se como critério de parada uma quantidade de gerações igual a 100 e para cada parametrização avaliou-se 30 repetições. Os resultados foram comparados com aqueles obtidos utilizando-se programação linear e programação linear inteira. Para a programação inteira considerou-se a melhor ...
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