21 resultados para Carrying capacity

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Agriculture is one of the most important and possibly the oldest economic activity developed by humans. This activity was developed extensively and is becoming more and more dependent on development of technologies. The goal of this manuscript was examining some patents related to technologies developed for improving crop yields. Such patents are mainly related to more efficient formulations of agrochemicals and management techniques of plants, cattle and natural resources. A brief comment is carried out about bioprospection and related problems, relating, for example the case of Cupuaçu. The article is concluded mentioning that the development of policies and management strategies that increase agricultural yield and simultaneously preserve or conserve natural resources should also be prioritized, because certainly this is the only way we have to get the real sustainability and to improve life quality abroad the world.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Oxygen-binding properties, blood gases, and acid-base parameters were studied in tegu lizards, Tupinambis merianae, at different seasons and temperatures. Independent of temperature and pH, blood oxygen affinity was higher in dormant lizards than in those active during the summer. Haematocrit (Hct) and hemoglobin content ([Hb]) were greater in active lizards resulting in a higher oxygen-carrying capacity. Nucleoside triphosphate content ([NTP]) was reduced during dormancy, but the ratio between [NTP] and [Hb] remained unchanged. Dormancy was accompanied by an increase in plasma bicarbonate ([HCO(3)(-)]PI) and an elevation of arterial CO(2) partial pressure (P(aCO2)) and CO(2) content in the plasma (C(PlCO2)). These changes in acid-base parameters persist over a broad range of body temperatures. In vivo, arterial O(2) partial pressure (Pa(O2)) and O(2) content (Ca(O2)) were not affected by season and tended to increase with temperature. Arterial pH (pH(a)) of dormant animals is reduced compared to active lizards at body temperatures below 15 degreesC, while no significant difference was noticed at higher temperatures. (C) 2003 Elsevier B.V. All rights reserved.

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We examine the classical problem of the existence of a threshold size for a patch to allow for survival of a given population in the case where the patch is not completely isolated. The surrounding habitat matrix is characterized by a non-zero carrying capacity. We show that a critical patch size cannot be strictly defined in this case. We also obtain the saturation density in such a patch as a function of the size of the patch and the relative carrying capacity of the outer region. We argue that this relative carrying capacity is a measure of the isolation of the patch. Our results are then compared with conclusions drawn from observations of the population dynamics of understorey birds in fragments of the Amazonian forest and shown to qualitatively agree with them, offering an explanation for the importance of dispersal and isolation in these observations. Finally, we show that a generalized critical patch size can be introduced resorting to threshold densities for the observation of a given species.

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A Política Nacional do Meio Ambiente tem como objetivo a conciliação do desenvolvimento econômico e social com a qualidade ambiental, e dispõe de vários instrumentos que procuram contemplara capacidade de suporte do meio. Assim, a discussão sobre a localização das atividades é uma etapa importante para a avaliação da viabilidade ambiental de um determinado empreendimento, notadamente em processos de licenciamento ambiental. O trabalho apresenta uma abordagem metodológica para integração de critérios técnicos, ambientais e sociais em estudos de alternativas de localização de aterros sanitários, com especial atenção à interação entre os aspectos ambientais e os elementos fundamentais de um projeto (a saber, requisitos locacionais e concepção tecnológica), aplicado em um estudo de caso em São Carlos (SP). Como resultados principais, destacam-se o maior foco nos impactos significativos e a possibilidade de envolvimento de segmentos importantes da sociedade previamente à elaboração dos estudos ambientais.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Heros Augusto Santos Lobo & Edvaldo Cesar Moretti: Tourism in Caves and the Conservation of the Speleological Heritage: The case of Serra da Bodoquena (Mato Grosso do Sul State, Brazil)The Serra da Bodoquena is the region in the state of Mato Grosso do Sul, Brazil in which the Municipality of Bonito is located. This municipality is the primary calling card for tourism in the state and is one of the most developed areas of ecotourism and speleotourism in the country The tourism there is entitled ecotourism, and is designed to be sustainable. The present case study focuses on the ecologically Sustainable aspects of the spleotourism practiced there, especially the proposals for tourist carrying capacity adopted. The results and discussion provide Suggestions for the adoption of a different formulation of carrying capacity focusing on both operational and quantitative aspects. Ecologically Sustainable speleotourism in the Serra da Bodoquena should be possible as long as new proposals limiting visitation are adopted which conform to technical environmental management procedures and consider the interests of local stakeholders.

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Due to a shortage of textbooks with specific data on muscular activity concerning physical conditioning and sports, we analysed electromyographically the muscles pectoralis major and deltoideus anterior, bilaterally, in inclined flying exercises, during the concentric and eccentric phases, with external loads of 25, 50, 75 and 100% of the maximum load. The electromyographic analysis was performed in eleven male volunteers with MEDITRACE-200 surface electrodes connected to a six-channel biologic signal acquisition module coupled to a PC/AT computer. The electromyographic signals were processed and the obtained effective values were normalized through maximum voluntary isometric contraction. Statistically, the results showed that all the muscles studied presented significant differences between the concentric and the eccentric phases, with higher electromyographic activity during the concentric phase. By analysing the different loads for each muscle in both phases, significant electromyographic activity was observed for all muscles. When the effect of each load on each muscle during the concentric phase was analysed, it was noticed that the muscles on the left were more active than those on the right side, while in the eccentric phase the muscles had different behavior.

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The tourist use of Santana cave provides a row of environmental damages, compromising partially the pristine conditions. Among the measures adopted to avoid this situation, this issue presents a contribution for the physical limits to tourist visitation and the indications for speleotouristic management. It was used the Cifuentes Carrying Capacity method and some basic principles of Visitors Impact Management Framework - VIM. The results show a Real Carrying Capacity (CCR) about 120 visits daily on the cave. The discussions raise a few hypotheses about the alteration in the method used and the temporal frequency between visitors groups, suggesting a provisional CCR of 117 and 135 visitors daily, respectively, during the week and in the weekends and holidays. The conclusions appoint the necessity of a conceptual revision in the Carrying Capacity methods, mainly about its adaptation for tourist management in caves. In the case studied, it is suggested the immediate beginning of environmental monitoring of the cave, to verify the plausibility from proposed visitation limits and the possible contributions for to mitigate the environmental impacts from speleotourism.

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The study area comprises the western portion of the Marília Plateau, State of São Paulo, southeastern Brazil. The geological substrate encompasses Cretaceous sedimentary rocks of the Bauru Group and local Neocenozoic units like colluvium aprons, fluvial terrace deposits, in situ regoliths, and modern alluvial deposits. In a geomorphologic sense, the study area might be characterized as showing two main pediplanes, viz. P1 Surface (upper) and P2 Surface (lower), both surfaces are presently under dissecation processes. After the 1920's the expansion of the railroad system fostered the removal of the natural vegetation, which in turn was followed by the introduction of coffee, peanut, corn and cotton crops. This intense exploitation was conducted without respect to the soil carrying capacity and its natural susceptibility to erosional processes, including an aggressive form known as voçoroca. As a result, the study shows that the most susceptible material includes colluvium aprons, in situ regoliths, and colluvium-alluvium or alluvium deposits. The most critical situation is in the P2 Surface context, near the bottom of the Marília Plateau scarpment, where surface runoff can be very strong. Another point of active erosion is represented by the exposed walls of gullies and voçorocas, mainly in fluvial reaches subjected to talweg lowering. In a general sense, this study shows current evidence of erosional stability due to the ìntroduction of pastures as a predominant type of land occupation and to a series of erosion control procedures. Among these actions are terrace implantation, construction of small pits for runoff control, natural or induced reforestation by land owners. Despite these efforts, some erosion points remain chiefly in steeper country roads and trail stretches, in areas of concentration of cattle tracks (e.g., near cattle ponds), gullies or voçorocas exposed walls, and badly planned urbanization. The permanence of these erosion points demonstrates the necessity of a continuous monitoring of surface dynamics as well as a rapid and effective intervining measures of erosion and/or silting control.

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We introduce a new method to improve Markov maps by means of a Bayesian approach. The method starts from an initial map model, wherefrom a likelihood function is defined which is regulated by a temperature-like parameter. Then, the new constraints are added by the use of Bayes rule in the prior distribution. We applied the method to the logistic map of population growth of a single species. We show that the population size is limited for all ranges of parameters, allowing thus to overcome difficulties in interpretation of the concept of carrying capacity known as the Levins paradox. © Published under licence by IOP Publishing Ltd.

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Pós-graduação em Física - IFT