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| Registros recuperados: 202 | |
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| CORRÊA, E. S.; COSTA, F. P.; CEZAR, I. M.; MACEDO, M. C. M.; EUCLIDES FILHO, K.; EUCLIDES, V. P. B.; ZIMMER, A. H.. |
| A Embrapa Gado de Corte trabalha com modelos físicos de produção desde 1983. O último sistema implantado incluía a cria, recria e engorda de animais Nelore, sendo os machos suplementados em pasto na primeira seca e terminados em confinamento na segunda seca, com 24 meses de idade. Encerrada essa etapa, iniciou-se discussão para definir o novo sistema a implementar. Combinando duas taxas de lotação das pastagens (1,8 e 1,32 UA/ha) e diferentes estratégias de suplementação no período seco (ração concentrada e sal protéico), seis sistemas alternativos (e um sistema tradicional tomado como referência) foram então delineados e avaliados por meio de simulações com uma planilha eletrônica que permite projetar o desenvolvimento de uma fazenda em um horizonte de... |
| Tipo: Documentos (INFOTECA-E) |
Palavras-chave: Bovino de corte; Aspecto econômico; Simulation; Economic situation.; Modelo de Simulação; Sistema de Produção.; Beef cattle; Farming systems.. |
| Ano: 2003 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/325800 |
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| Guyader, Olivier. |
| With a thin economic component, most bio-economic models of fisheries fail to assess the effects of the regulation systems on firms. In order to analyse the short term consequences of different management schemes, a simulation model is applied to the French driftnet albacore fleet: licence allocation with driftnet regulation, individual quotas, and individual transferable quotas without any input control. Vessel technology is estimated by using the data collected, and groups of vessels are distinguished according to criteria of performance. We present the adjustment within firms and between groups under different scenarios (limited entry with and without driftnet regulation, individual quotas and individual transferable quotas allocation), and we compare... |
| Tipo: Text |
Palavras-chave: Albacore tuna; Dolphin; Driftnet; Fisheries; ITQ; Licence; Quasi-rent; Quota price; Quotas; Regulation; Simulation. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00244/35523/34036.pdf |
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| Vandeputte, Marc; Fraslin, Clemence; Haffray, Pierrick; Bestin, Anastasia; Allal, Francois; Kocour, Martin; Prchal, Martin; Dupont-nivet, Mathilde. |
| Fillet yield (i.e. the proportion of edible muscle in a fish) is a key economic trait for species sold as fillets. Its genetic improvement is complicated by several of its characteristics 1) it is a ratio trait, 2) its numerator (fillet weight) and denominator (body weight) are strongly correlated (correlations in the range 0.89-0.99), 3) it offers little phenotypic variation and 4) it cannot be measured on alive breeding candidates. In a former study, we showed that it could be improved by selection, especially with three selection indices, fillet yield, residual fillet weight and a ratio-specific linear index. However, it is well known that the heritability of ratio traits does not permit a reliable prediction of genetic gains. As predictability of... |
| Tipo: Text |
Palavras-chave: Aquaculture; Genetics; Heritability; Selection; Linear index; Residual fillet weight; Selection response; Simulation; Processing yields. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00612/72378/71390.pdf |
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| Monbet, Valérie; Ailliot, P; Prevosto, Marc. |
| The knowledge of sea state and wind conditions is of central importance for many offshore and nearshore operations. In this paper, we make a complete survey of stochastic models for sea state and wind time series. We begin with methods based on Gaussian processes, then non-parametric resampling methods for time series are introduced followed by various parametric models. We also propose an original statistical method, based on Monte Carlo goodness-of-fit tests, for model validation and comparison and this method is illustrated on an example of multivariate sea state time series. (C) 2006 Elsevier Ltd. All rights reserved. |
| Tipo: Text |
Palavras-chave: Model validation; Simulation; Nonlinear time series; Wind; Sea state. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2679.pdf |
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| Heath, Michael R.; Speirs, Douglas C.; Steele, John H.. |
| Climate fluctuations and human exploitation are causing global changes in nutrient enrichment of terrestrial and aquatic ecosystems and declining abundances of apex predators. The resulting trophic cascades have had profound effects on food webs, leading to significant economic and societal consequences. However, the strength of cascades-that is the extent to which a disturbance is diminished as it propagates through a food web-varies widely between ecosystems, and there is no formal theory as to why this should be so. Some food chain models reproduce cascade effects seen in nature, but to what extent is this dependent on their formulation? We show that inclusion of processes represented mathematically as density-dependent regulation of either consumer... |
| Tipo: Text |
Palavras-chave: Bottom-up; Density dependence; Food chain; Food web; Harvesting; Model; Predator-prey; Simulation; Top-down. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00171/28249/26505.pdf |
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| Kermorvant, Claire; Caill-milly, Nathalie; D'Amico, Frank; Bru, Noelle; Sanchez, Florence; Lissardy, Muriel; Brown, Jennifer. |
| Bivalves are important components of benthic marine and freshwater ecosystems throughout the world. One of the most exploited bivalves used for human consumption is manila clam (Venerupis philippinarum). In Arcachon Bay (SW France), commercial fishers and scientists have developed a monitoring survey to estimate clam stocks to assist in implementing a sustainable management strategy. The survey design that is currently used is based on standard stratified random sampling (StRS). The survey has been undertaken every 2 years since 2006. Each survey costs approximately (sic) 50 000, with funding provided by similar to 20% of the commercial fishers. The survey is quite expensive, given that this resource is managed mostly at a regional level. In 2016 for... |
| Tipo: Text |
Palavras-chave: Venerupis philippinarum; Bivalve; Simulation; Survey; Arcachon Bay; GRTS. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00410/52102/52808.pdf |
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| Charuau, Anatole. |
| Fishing crayfish on the gulf's mudflats is a traditional business practised by 450 boats of 12 to 18 metres in length and employs 2,500 sailors. In the north of the gulf, this activity is exclusive, in the south, immature hake are also caught, because the crayfish areas coincide, in part, with the nurseries of the northern stock of this species. Management of these fisheries, called mixed, of crayfish and hake is one of the greatest problems of the Gulf of Gascony. All assessments tend to show the responsibility of the crayfish boats in the future of the hake stock. The solution is likely to pass through a generalised increase of the 80 mm meshing that would lead, eventually, the hake stock yield to its maximum, but would eliminate a great many trades... |
| Tipo: Text |
Palavras-chave: Mixed fisheries; Bio economical modelisation; Bay of Biscay; Simulation; Prawn; Hake; Fishing fleet strategy; Fishing assessment; Pecherie mixre; Golfe de Gascogne; Modele bio economique; Simulation; Langoustine; Merlu; Stratégie des flottilles; Gestion des pêcheries. |
| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/1988/rapport-2569.pdf |
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| Registros recuperados: 202 | |
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