891 resultados para carrying capacity, population, limits, sustainability, planning, resilience


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As cianobactérias Microcystis aeruginosa e Planktothrix agardhii são espécies formadoras de florações comuns em ecossistemas aquáticos eutrofizados. Nestes ambientes, a disponibilidade de luz é um dos fatores determinantes para o desenvolvimento e estruturação da comunidade fitoplanctônica. O presente estudo teve como objetivo investigar o efeito da luz na fisiologia de cepas de cianobactérias (M. aeruginosa e P. agardhii), avaliando o crescimento, a variabilidade inter e intra-específica e a competição por luz. Para tanto foram realizados cultivos estanques em diferentes intensidades luminosas (10, 40, 60, 100 e 500 mol m-2 s-1) e calculadas as taxas de crescimento e os rendimentos máximos das culturas. O requerimento mínimo de luz de cada cepa foi determinado em experimentos com monoculturas em sistemas de cultivo contínuo (quimiostatos) sob condições de limitação de luz. A competição por luz foi avaliada através de experimentos com biculturas em quimiostatos. Foi observada variabilidade intra e inter-específica das cepas, nas diferentes intensidades luminosas testadas. Em 500 μmol m-2 s-1, as cepas de M. aeruginosa obtiveram maior biomassa do que P. agardhii, corroborando a maior sensibilidade de P. agardhii luz. Embora com rendimento máximo menor, P. agardhii cresceu em intensidades luminosas consideradas elevadas para a espécie, 100 e 500 μmol m-2 s-1. Estes resultados evidenciam a capacidade de P. agardhii ocorrer em ambientes com grandes amplitudes de luminosidade. Na intensidade de 10 μmol m-2 s-1, M. aeruginosa e P. agardhii apresentaram crescimento semelhante, demonstrando a habilidade das duas espécies em crescer com pouca luz. Nas monoculturas em quimiostato, sob condições de limitação de luz, as cepas de M. aeruginosa atingiram maior biomassa durante o equilíbrio (steady-state) do que P. agadhii, refletindo uma capacidade suporte mais elevada, enquanto que os valores de requerimento mínimo de luz foram semelhantes entre as duas espécies. Ao competirem, M. aeruginosa superou P. agardhii imediatamente após o início do experimento. Esse rápido crescimento resultou na dominância de M. aeruginosa em todos os pares de cepas testados e, em dois casos, ocorreu exclusão competitiva de P. agardhii. Quando não ocorreu exclusão, P. agardhii conseguiu manter-se no sistema com uma baixa biomassa (ca.15%). Estes resultados ajudam a entender a co-ocorrência destas espécies no ambiente e a dominância de M. aeruginosa mesmo em condições de baixa luminosidade.

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O objetivo desta tese é traçar um panorama histórico das políticas públicas de planejamento familiar do Estado brasileiro, inserindo-o no contexto da complexa conjuntura sociopolítico-econômica no período de 1980 até a atualidade. Mediante pesquisa bibliográfica e documental, investigam-se, na interseção das políticas para população, mulher e saúde, as influências e interesses que incidem sobre programas de planejamento familiar. Após recuperar brevemente a trajetória dos movimentos de mulheres e feministas, que constituíram atores sociais centrais no debate sobre as políticas de população e de planejamento familiar, focaliza-se a drástica redução nas taxas de fecundidade da mulher brasileira ocorrida a partir dos anos 1960, na vigência oficial de uma política natalista, mas na omissão do Estado ao permitir a difusão no país de organizações de cunho controlista, que viabilizaram às mulheres o acesso à pílula anticoncepcional e à esterilização. Acompanha-se a evolução das políticas de população em nível mundial, destacando a atuação da Organização das Nações Unidas e de suas conferências mundiais, focalizando a Conferência Internacional de População e Desenvolvimento realizada no Cairo em 1994, que provocou uma inflexão nas políticas de saúde da mulher para saúde reprodutiva. No Brasil, que já contava com um programa pioneiro de saúde da mulher o Paism (1983) , os efeitos do Cairo vieram somar-se à definição do planejamento familiar pela Constituição de 1988 e à instituição do Sistema Único de Saúde em 1990. A análise permitiu identificar as influências externas e internas que incidem sobre a política de planejamento familiar. A política de planejamento familiar do país hoje configura-se democrática, abrangente e descentralizada, sendo a principal tensão identificada entre seus enunciados e sua implementação na prática, ou seja, só será efetiva se houver um controle social eficaz.

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This paper deals with the development and use of biological reference points for salmon conservation on the River Lune, England. The Lune supports recreational and net fisheries with annual catches in the region of 1,000 and 1356 salmon respectively. Using models transported from other river systems, biological reference points exclusive to the Lune were developed; specifically the number of eggs deposited and carrying capacity estimates for age 0+ and 1+ parr. The conservation limit was estimated at 11.9 million eggs and between 1989 and 1998 was exceeded in two years. Comparison of juvenile salmon densities in 1991 and 1997 with estimates of carrying capacity indicated that 0+ and 1+ parr densities were at around 60 % of carrying capacity and may relate to the number of eggs deposited in 1990 and 1996 being approximately 70% of the target value. The paper discusses the management actions taken in order to ensure that the management target of the conservation limit being met four years out of five is delivered. It also discusses the balance between conservation and exploitation and the socio-economic decisions made in order to ensure parity of impacts on the rod and net fisheries. The regulations have been enforced since 1999 and the paper concludes with an assessment of the actions taken to deliver the management targets, over the last five years.

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A modification of the Schaefer surplus-production model was used to account for environmental induced variations of shrimp (Penaeus vannamei) catch in northern Peru. Based on time series of catch, effort, river discharge and sea surface temperature, fluctuations in catch of shrimps are explained and discussed with respect to multiple level of carrying capacity and hence different maximum sustainable yields.

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In the eastern United States as well as in many countries where most shellfish originate in public beds, shellfishermen, local communities, distributors, and consumers have been dependent on wild stocks for shellfish supplies. Abundance of shellfish is usually much lower than the carrying capacity of the beds and can fluctuate widely among seasons. Thus shellfisheries are built upon a relatively weak foundation: Uncertin supplies, abundance of which is governed by several natural factors.

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As vigas casteladas já são utilizadas em diversos tipos de estruturas para se vencer grandes vãos. Há uma nova realidade para o uso de perfis castelados, agora em aço inoxidável. Este trabalho apresenta uma análise comparativa entre vigas casteladas e vigas de alma cheia em perfis IPE, baseadas na norma europeia, no método da resistência contínua; e, também, através de um modelo em elementos finitos desenvolvido no programa Ansys. Este trabalho tem como objetivo verificar o comportamento e a resistência à flexão das vigas casteladas em aço inoxidável. As não-linearidades físicas e geométricas foram incorporadas aos modelos, a fim de se mobilizar totalmente a capacidade resistente desta estrutura. A não-linearidade do material foi considerada através do critério de plastificação de von Mises e da lei constitutiva tensão versus deformação multi-linear, de forma a exibir um comportamento elasto-plástico com encruamento. A não-linearidade geométrica foi considerada a partir de uma formulação de Lagrange atualizado. Os resultados numéricos das vigas em estudo foram avaliados quanto aos modos de falha e da distribuição de tensões. Os momentos resistentes analíticos foram comparados com os resultados do modelo numérico apresentando valores satisfatórios e a favor da segurança.

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◾ Report of Opening Session (p. 1) ◾ Report of Governing Council (p. 15) ◾ Report of the Finance and Administration Committee (p. 47) ◾ Reports of Science Board and Committees: Science Board Inter-sessional Meeting (p. 63); Science Board (p. 73); Biological Oceanography Committee (p. 87); Fishery Science Committee (p. 95); Marine Environmental Quality Committee (p. 105); MONITOR Technical Committee (p. 115); Physical Oceanography and Climate Committee (p. 125); Technical Committee on Data Exchange (p. 133) ◾ Reports of Sections, Working and Study Groups: Section on Carbon and Climate (p. 139); Section on Ecology of Harmful Algal Blooms in the North Pacific (p. 143); Working Group 18 on Mariculture in the 21st Century - The Intersection Between Ecology, Socio-economics and Production (p. 147); Working Group 19 on Ecosystem-Based Management Science and its Application to the North Pacific (p. 151); Working Group 20 on Evaluations of Climate Change Projections (p. 157); Working Group 21 on Non-indigenous Aquatic Species (p. 159); Study Group to Develop a Strategy for GOOS (p. 165) ◾ Reports of the Climate Change and Carrying Capacity Scientific Program: Implementation Panel on the CCCC Program (p. 169); CFAME Task Team (p. 175); MODEL Task Team (p. 181) ◾ Reports of Advisory Panels: Advisory Panel for a CREAMS/PICES Program in East Asian Marginal Seas (p. 187); Advisory Panel on Continuous Plankton Recorder Survey in the North Pacific (p. 193); Advisory Panel on Iron Fertilization Experiment in the Subarctic Pacific Ocean (p. 197); Advisory Panel on Marine Birds and Mammals (p. 201); Advisory Panel on Micronekton Sampling Inter-calibration Experiment (p. 205) ◾ Summary of Scientific Sessions and Workshops (p. 209) ◾ Membership List (p. 259) ◾ List of Participants (p. 277) ◾ List of PICES Acronyms (p. 301) ◾ List of Acronyms (p. 303)

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Report of Opening Session (p. 1). Report of Governing Council (p. 15). Report of the Finance and Administration Committee (p. 65). Reports of Science Board and Committees: Science Board Inter-Sessional Meeting (p. 83); Science Board (p. 93); Biological Oceanography Committee (p. 105); Fishery Science Committee (p. 117); Marine Environmental Quality Committee (p. 129); Physical Oceanography and Climate Committee (p. 139); Technical Committee on Data Exchange (p. 145); Technical Committee on Monitoring (p. 153). Reports of Sections, Working and Study Groups: Section on Carbon and Climate (p. 161); Section on Ecology of Harmful Algal Blooms in the North Pacific (p. 167); Working Group 19 on Ecosystem-based Management Science and its Application to the North Pacific (p. 173); Working Group 20 on Evaluations of Climate Change Projections (p. 179); Working Group 21 on Non-indigenous Aquatic Species (p. 183); Study Group to Develop a Strategy for GOOS (p. 193); Study Group on Ecosystem Status Reporting (p. 203); Study Group on Marine Aquaculture and Ranching in the PICES Region (p. 213); Study Group on Scientific Cooperation between PICES and Non-member Countries (p. 225). Reports of the Climate Change and Carrying Capacity Program: Implementation Panel on the CCCC Program (p. 229); CFAME Task Team (p. 235); MODEL Task Team (p. 241). Reports of Advisory Panels: Advisory Panel for a CREAMS/PICES Program in East Asian Marginal Seas (p. 249); Advisory Panel on Continuous Plankton Recorder Survey in the North Pacific (p. 253); Advisory Panel on Iron Fertilization Experiment in the Subarctic Pacific Ocean (p. 255); Advisory Panel on Marine Birds and Mammals (p. 261); Advisory Panel on Micronekton Sampling Inter-calibration Experiment (p. 265). 2007 Review of PICES Publication Program (p. 269). Guidelines for PICES Temporary Expert Groups (p. 297). Summary of Scientific Sessions and Workshops (p. 313). Report of the ICES/PICES Conference for Early Career Scientists (p. 355). Membership (p. 367). Participants (p. 387). PICES Acronyms (p. 413). Acronyms (p. 415).

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An experiment was conducted in the laboratory condition to determine the effect of organic (poultry drop, cow dung and mustard oil cake) and inorganic fertilizer (urea) on production, reproduction rate and maturation time of Moina species. Production rate was also determined in both aerated and non-aerated system in plastic containers with carrying capacity of 2.5-liter each. Total production was significantly higher in both aerated (2475 individuals/2.5 l water) and non-aerated (3253 individuals/2.5 l water) containers using poultry manure compared to other fertilizers. Moreover, the reproduction rate and maturation time in poultry drops showed distinct efficacy in Moina species. Reproduction rate of 11 individuals was the maximal while lowest maturation time was found 78 hours. Reproduction and maturation were induced surprisingly in test tube where the aeration system was absent.

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Student projects included: conservation and protection of critical coral habitats in Phuket; assessing the carrying capacity on conservation and protection strategies; proactive stakeholder strategy to tackle an environmental threat; improving the environmental management through participation and sustainable freshwater management. All of these projects were conducted on Racha Yai Island in Phuket.

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In a fibre-optic communication network, the wavelength-division multiplexing (WDM) technique enables an expansion of the data-carrying capacity of optical fibres. This can be achieved by transmitting different channels on a single optical fibre, with each channel modulating a different wavelength. In order to access and manipulate these channels at a node of the network, a compact holographic optical switch is designed, modelled, and constructed. The structure of such a switch consists of a series of optical components which are used to collimate the beam from the input, de-multiplex each individual wavelength into separated channels, manipulate the separated channels, and reshape the beam to the output. A spatial light modulator (SLM) is crucial in this system, offering control and flexibility at the channel manipulation stage, and providing the ability to redirect light into the desired output fibre. This is achieved by the use of a 2-D analogue phase computer generated hologram (CGH) based on liquid crystal on silicon (LCOS) technology. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

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An engineer assessing the load-carrying capacity of an existing reinforced concrete slab is likely to use elastic analysis to check the load at which the structure might be expected to fail in flexure or in shear. In practice, many reinforced concrete slabs are highly ductile in flexure, so an elastic analysis greatly underestimates the loads at which they fail in this mode. The use of conservative elastic analysis has led engineers to incorrectly condemn many slabs and therefore to specify unnecessary and wasteful flexural strengthening or replacement. The lower bound theorem is based on the same principles as the upper bound theorem used in yield line analysis, but any solution that rigorously satisfies the lower bound theorem is guaranteed to be a safe underestimate of the collapse load. Jackson presented a rigorous lower bound method that obtains very accurate results for complex real slabs.

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The quasi-static and dynamic responses of laminated beams of equal areal mass, made from monolithic CFRP and Ultra high molecular weight Polyethylene (UHMWPE), have been measured. The end-clamped beams were impacted at mid-span by metal foam projectiles to simulate localised blast loading. The effect of clamping geometry on the response was investigated by comparing the response of beams bolted into the supports with the response of beams whose ends were wrapped around the supports. The effect of laminate shear strength upon the static and dynamic responses was investigated by testing two grades of each of the CFRP and UHMWPE beams: (i) CFRP beams with a cured matrix and uncured matrix, and (ii) UHMWPE laminates with matrices of two different shear strengths. Quasi-static stretch-bend tests indicated that the load carrying capacity of the UHWMPE beams exceeds that of the CFRP beams, increases with diminishing shear strength of matrix, and increases when the ends are wrapped rather than through-bolted. The dynamic deformation mode of the beams is qualitatively different from that observed in the quasi-static stretch-bend tests. In the dynamic case, travelling hinges emanate from the impact location and propagate towards the supports; the beams finally fail by tensile fibre fracture at the supports. The UHMWPE beams outperform the CFRP beams in terms of a lower mid-span deflection for a given impulse, and a higher failure impulse. Also, the maximum attainable impulse increases with decreasing shear strength for both the UHMWPE and CFRP beams. The ranking of the beams for load carrying capacity in the quasi-static stretch-bend tests is identical to that for failure impulse in the impact tests. Thus, the static tests can be used to gauge the relative dynamic performances of the beams. © 2013 Elsevier Ltd. All rights reserved.

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This paper describes first some of the recent performance checks on the high performance fibre-reinforced cementitious composite CARDIFRC and then its application to the retrofitting of damaged concrete beams. It is shown that an even distribution of fibres throughout the bulk of the material is crucial to its excellent fatigue performance and to the reduction in the autogenous shrinkage strains. The distribution of fibres in beams, cylinders and strips is examined using computerised tomography imaging and traditional image analysis. Thin strips of CARDIFRC are used to retrofit damaged concrete beams which are subjected to thermal cycling. It is shown that neither the load carrying capacity of the retrofitted beams nor the bond between retrofit strips and concrete deteriorates with thermal cycling. The load carrying capacity of retrofitted beams is predicted with a model based on fracture mechanics, and the predictions are shown to be in good agreement with test data. © 2006 Elsevier Ltd. All rights reserved.

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The Sleeping Beauty (SB) transposon system, derived from teleost fish sequences, is extremely effective at delivering DNA to vertebrate genomes, including those of humans. We have examined several parameters of the SB system to improve it as a potential, nonviral vector for gene therapy. Our investigation centered on three features: the carrying capacity of the transposon for efficient integration into chromosomes of HeLa cells, the effects of overexpression of the SB transposase gene on transposition rates, and improvements in the activity of SB transposase to increase insertion rates of transgenes into cellular chromosomes. We found that SB transposons of about 6 kb retained 50% of the maximal efficiency of transposition, which is sufficient to deliver 70-80% of identified human cDNAs with appropriate transcriptional regulatory sequences. Overexpression inhibition studies revealed that there are optimal ratios of SB transposase to transposon for maximal rates of transposition, suggesting that conditions of delivery of the two-part transposon system are important for the best gene-transfer efficiencies. We further refined the SB transposase to incorporate several amino acid substitutions, the result of which led to an improved transposase called SB11. With SB11 we are able to achieve transposition rates that are about 100-fold above those achieved with plasmids that insert into chromosomes by random recombination. With the recently described improvements to the transposon itself, the SB system appears to be a potential gene-transfer tool for human gene therapy.