11,678 research outputs found

    Análise do comércio do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763), no município de Macapá-AP.

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    O caranguejo-uçá é um importante recurso pesqueiro que se encontra sobre explorado em todo litoral brasileiro. Desempenha papel tanto econômico, quando fonte de renda para os atores da cadeia produtiva, quanto ecológico, na manutenção dos ecossistemas de mangues. No Amapá têm ocorrência em três municípios (Amapá, Calçoene e Oiapoque), e é comercializado principalmente no município de Macapá, tornando de fundamental importância a caracterização desta atividade, uma vez que este é o primeiro estudo sobre o comércio da espécie no Estado. Durante nove meses (outubro/2008 a junho/2009) foram realizadas visitas mensais (n=32) às feiras do Mercado Central do Igarapé das Mulheres para aplicação de entrevistas com os vendedores de caranguejo, e para o levantamento de dados biométricos de largura e comprimento do tefalotórax (CC e LC) dos animais comercializados. Aleatoriamente, foram adquiridos 854 exemplares machos que apresentaram LC média de 85,4 mm e CC médio de 65 mm. Verificou-se que os caranguejos comercializados são capturados principalmente nos municípios amapaenses. Os resultados obtidos indicam que há alterações de preço durante o ano, e que essa oscilação está relacionada à oferta com que este recurso é disponibilizado. Os dados obtidos mostram ainda, que houve comercialização durante o período de defeso na Feira do Mercado Central e que os animais comercializados procedem em maior parte de municípios paraenses. De modo geral, concluímos que a Portaria Estadual está sendo respeitada em relação ao tamanho mínimo de captura e a não comercialização de fêmeas, no entanto, os caranguejos continuam a serem comercializados no período legalmente proibido

    Numerical study of augmented lagrangian algorithms for constrained global optimization

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    To cite this article: Ana Maria A.C. Rocha & Edite M.G.P. Fernandes (2011): Numerical study of augmented Lagrangian algorithms for constrained global optimization, Optimization, 60:10-11, 1359-1378This article presents a numerical study of two augmented Lagrangian algorithms to solve continuous constrained global optimization problems. The algorithms approximately solve a sequence of bound constrained subproblems whose objective function penalizes equality and inequality constraints violation and depends on the Lagrange multiplier vectors and a penalty parameter. Each subproblem is solved by a population-based method that uses an electromagnetism-like (EM) mechanism to move points towards optimality. Three local search procedures are tested to enhance the EM algorithm. Benchmark problems are solved in a performance evaluation of the proposed augmented Lagrangian methodologies. A comparison with other techniques presented in the literature is also reported

    Utilitarian placement of composite services

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    The emergence of distributed clouds opens up new research challenges for service deployment. Composite services consist of multiple components, potentially located in different geographical locations, which need to be interconnected and invoked in the correct order according to the overall service work-flow. The placement of composite services over distributed cloud node locations raises new challenges for efficient deployment and management. In this paper, we design exact models of the composite service placement problems using Mixed Integer Linear Program (MILP), and compare these to solutions based on genetic algorithms. We use a utility function, based initially on latency metrics, to evaluate the quality of service (QoS) of the deployed composite service. By maximizing the utility with respect to deployment cost, our approach can provide good QoS for users while satisfying budget constraints for service providers. Based on simulations using real data-center locations and traffic demand patterns, we show that our algorithms are scalable under a range of scenarios.This work has been supported in part by the FP7 FUSION (grant agreement 318205), in part by the U.S. Army Research Laboratory and the U.K. Ministry of Defence (agreement number W911NF-16-3-0001), in part by the H2020 5G-MEDIA (grant agreement 761699) and in part by the CHIST-ERA CONCERT (grant agreement I1402) projects.info:eu-repo/semantics/publishedVersio

    Von Bertalanffy's dynamics under a polynomial correction: Allee effect and big bang bifurcation

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    In this work we consider new one-dimensional populational discrete dynamical systems in which the growth of the population is described by a family of von Bertalanffy's functions, as a dynamical approach to von Bertalanffy's growth equation. The purpose of introducing Allee effect in those models is satisfied under a correction factor of polynomial type. We study classes of von Bertalanffy's functions with different types of Allee effect: strong and weak Allee's functions. Dependent on the variation of four parameters, von Bertalanffy's functions also includes another class of important functions: functions with no Allee effect. The complex bifurcation structures of these von Bertalanffy's functions is investigated in detail. We verified that this family of functions has particular bifurcation structures: the big bang bifurcation of the so-called "box-within-a-box" type. The big bang bifurcation is associated to the asymptotic weight or carrying capacity. This work is a contribution to the study of the big bang bifurcation analysis for continuous maps and their relationship with explosion birth and extinction phenomena.info:eu-repo/semantics/publishedVersio

    GeoCLEF 2006: the CLEF 2006 Ccross-language geographic information retrieval track overview

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    After being a pilot track in 2005, GeoCLEF advanced to be a regular track within CLEF 2006. The purpose of GeoCLEF is to test and evaluate cross-language geographic information retrieval (GIR): retrieval for topics with a geographic specification. For GeoCLEF 2006, twenty-five search topics were defined by the organizing groups for searching English, German, Portuguese and Spanish document collections. Topics were translated into English, German, Portuguese, Spanish and Japanese. Several topics in 2006 were significantly more geographically challenging than in 2005. Seventeen groups submitted 149 runs (up from eleven groups and 117 runs in GeoCLEF 2005). The groups used a variety of approaches, including geographic bounding boxes, named entity extraction and external knowledge bases (geographic thesauri and ontologies and gazetteers)

    Challenges to evaluation of multilingual geographic information retrieval in GeoCLEF

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    This is the third year of the evaluation of geographic information retrieval (GeoCLEF) within the Cross-Language Evaluation Forum (CLEF). GeoCLEF 2006 presented topics and documents in four languages (English, German, Portuguese and Spanish). After two years of evaluation we are beginning to understand the challenges to both Geographic Information Retrieval from text and of evaluation of the results of geographic information retrieval. This poster enumerates some of these challenges to evaluation and comments on the limitations encountered in the first two evaluations

    Production, breeding and potential of cowpea crop in Brazil.

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    About 50 years ago cowpea was reported as a relatively minor tropical legume. However, in the last years, it has been emerging as one of the most important food legume of the 21st century (SINGH, 2010). Brazil is not out of this panorama. Brazilian agriculture is undergoing major technological changes and, in addition, globalization in agribusiness has caused impacts on the production chain of several crops, particularly those heavily dependent on the use of a large volume of agricultural inputs, mainly fertilizers and pesticides. Such crops have had a higher production cost each year. On the other hand, this situation has brought new opportunities. Business farmers have sought new alternatives for their production arrangements. In this context cowpea constitutes one of the best options.bitstream/item/85620/1/Doc-216-Production.pd

    Zero Energy of Plane-Waves for ELKOs

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    We consider the ELKO field in interaction through contorsion with its own spin density, and we investigate the form of the consequent autointeractions; to do so we take into account the high-density limit and find plane wave solutions: such plane waves give rise to contorsional autointeractions for which the Ricci metric curvature vanishes and therefore the energy density is equal to zero identically. Consequences are discussed.Comment: 7 page
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