987 resultados para REDOX STATUS
Resumo:
Catch and effort assessment surveys have been used to assess trends in fish landings in Kenyan waters of Lake Victoria since 1976. Landings reached a maximum of 200000 t annually in 1989-1991 as Nile perch, Lates niloticus (L.), catches increased due to an expansion in stock size and increased fishing effort. CPUE peaked at 180 kg boat day-1 in 1989 and decreased thereafter with increasing effort. By 1998 total Nile perch catches were half those at the beginning of the decade despite increased effort. Catches of Rastrineobola argentea (Pellegrin) have levelled off despite increased effort.
Resumo:
The current situation of regional, rather' than national, problems of eutrophication in standing waters has been widely aired in recent reports. A reliable, quantitative data base is a prerequisite to future trend monitoring, a concensus view of those reports. The objective of this report is to establish requirements, methodology and a minimal data set for nutrient and algae status in water supply reservoirs in England which may be used as a protocol for future trend monitoring.A pilot study has been carried out to assess the relative merits of different sampling strategies, the choice of which has major implications for the cost of sample collection. This short report suggests that consider the possibility of designating a few sites as ”baseline sites” at which detailed changes in trophic status as monitored by the more labour-intensive parameters would be collected on a regular, long term basis to help in the interpretation of the low cost survey results.
Resumo:
Este estudo investiga o status da produção acadêmica sobre alfabetização em 2 (dois) programas de Mestrado e Doutorado em Educação no Estado do Rio de Janeiro. Partiu-se da concepção de que a organização e a sistematização das contribuições originárias das pesquisas realizadas nesses programas permitiriam um olhar mais apurado sobre a alfabetização enquanto objeto de estudo acadêmico no contexto do Rio de Janeiro. Busca-se, assim, demarcar a trajetória dessa mesma produção, destacando os aspectos que foram privilegiados ao longo do tempo. Toma-se como referência principal para a análise e entendimento das especificidades do lugar da alfabetização na produção acadêmica no Rio de Janeiro, a história da alfabetização no Brasil, demarcada em seus diferentes períodos. Em outras palavras, através da análise da produção acadêmica sobre o tema, buscou-se compreender a partir de que momento (quando) e de que modo (como) a alfabetização se constitui objeto de estudo (acadêmico) no contexto do Rio de Janeiro.
Resumo:
Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP). In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of the pPGI encoding gene, PGI1. Starch content in pgi1-3 source leaves was ca. 10-15% of that of wild type (WT) leaves, which was similar to that of leaves of pgi1-2, a T-DNA insertion pPGI null mutant. Starch deficiency of pgi1 leaves could be reverted by the introduction of a sex1 null mutation impeding beta-amylolytic starch breakdown. Although previous studies showed that starch granules of pgi1-2 leaves are restricted to both bundle sheath cells adjacent to the mesophyll and stomata guard cells, microscopy analyses carried out in this work revealed the presence of starch granules in the chloroplasts of pgi1-2 and pgi1-3 mesophyll cells. RT-PCR analyses showed high expression levels of plastidic and extra-plastidic beta-amylase encoding genes in pgi1 leaves, which was accompanied by increased beta-amylase activity. Both pgi1-2 and pgi1-3 mutants displayed slow growth and reduced photosynthetic capacity phenotypes even under continuous light conditions. Metabolic analyses revealed that the adenylate energy charge and the NAD(P) H/NAD(P) ratios in pgi1 leaves were lower than those of WT leaves. These analyses also revealed that the content of plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP)-pathway derived cytokinins (CKs) in pgi1 leaves were exceedingly lower than in WT leaves. Noteworthy, exogenous application of CKs largely reverted the low starch content phenotype of pgi1 leaves. The overall data show that pPGI is an important determinant of photosynthesis, energy status, growth and starch accumulation in mesophyll cells likely as a consequence of its involvement in the production of OPPP/glycolysis intermediates necessary for the synthesis of plastidic MEP-pathway derived hormones such as CKs.
Resumo:
A presente dissertação é fruto de uma investigação filosófica, inserida na linha de pesquisa de Ética. Esse trabalho aprofunda uma discussão polêmica no contexto da Bioética, a saber: a manipulação de células embrionárias. Contudo, o autor não envereda seus esforços nas conse-quências éticas advindas das novas tecnologias produzidas pela Engenharia Genética, mas adentra na causa do problema, isto é, pretende antes saber se o embrião humano é ser vivo, ser humano e, principalmente, pessoa. Assim, o autor tem como objetivo principal investigar o status ontológico e moral do embrião humano. Nesse contexto, investiga o conceito de identidade pessoal, examinando-o - brevemente - à luz de duas teorias da Filosofia da Mente: internalista, que defende a construção do eu por bases internas; e a externalista, que advoga a construção do eu por bases externas. Elenca e analisa os atributos essenciais que concebe uma pessoa. Também pesquisa o conceito de dignidade humana e sua vinculação ao conceito de pessoa, tendo como base a filosofia moral de Immanuel Kant, através de sua obra Fundamentação da Metafísica dos Costumes. Além desta e da bibliografia utilizada sobre o tema, a fonte principal dessa discussão é a obra Ética Prática, do filósofo Peter Singer. Vale destacar que existem três posições dominantes dentro dessa temática: a) Teoria Concepcionalista, a qual argumenta que o embrião é pessoa desde a concepção e, por isso, desautoriza qualquer manipulação; b) Teoria Genético-Desenvolvimentista, a qual defende a pessoalidade do embrião a partir de diferentes etapas do seu desenvolvimento biológico e, desse modo, defende as pesquisas biomédicas; c) Teoria da Potencialidade da Pessoa, a qual advoga que o embrião ainda não tem a pessoalidade, no entanto, é um potencial ser humano e pessoa, e, por essa razão, sua integridade deve ser preservada. Ao final, o autor enumera as principais implicações éticas, psicológicas, sociais e jurídicas, uma vez determinados os estatutos ontológico e moral do embrião humano.
Resumo:
This study takes a preliminary step towards investigating the reports of poor rod catches of coarse fish in the River Lune. These poor catches and concern over the possible loss of coarse fish from the Lower Lune is investigated, using creel census data from 1991. Historical data is used where available for comparative studies. The conclusion that this report comes to is that there is a problem with the recruitment of coarse fish within the population. Dace, roach and bream all show good growth rates but only poor if any recruitment. Historical investigations suggest that roach and bream may never have successfully recruited without artificial induced conditions. The situation with dace is of more concern as populations in other rivers in Northern England are also in decline, whilst historically they were naturally recruiting.
Resumo:
This paper summarizes current information on the American shad, Alosa sapidissima, and describes the species and its fishery. Emphasis is placed on (1) life history of the fish, (2) condition of the fishery by State and water areas in 1960 compared to 1896 when the last comprehensive description was made, (3) factors responsible for decline in abundance, and (4) management measures. The shad fishery has changed little over the past three-quarters of a century, except in magnitude of yield. Types of shad-fishing gear have remained relatively unchanged, but many improvements have been made in fishing techniques, mostly to achieve economy. In 1896 the estimated catch was more than 50 million pounds. New Jersey ranked first in production with about 14 million pounds, and Virginia second with 11 million pounds. In 1960 the estimated catch was slightly more than 8 million pounds. Maryland ranked first in production with slightly more than 1.5 million pounds, Virginia second with slightly less than 1.4 million pounds, and North Carolina third with about 1.3 million pounds. Biological and economic factors blamed for the decline in shad abundance, such as physical changes in the environment, construction of dams, pollution, over-fishing, and natural cycles of abundance, are discussed. Also discussed are methods used for the rehabilitation and management of the fishery, such as artificial propagation, installation of fish-passage facilities at impoundments, and fishing regulations. With our present knowledge, we can manage individual shad populations; but, we probably cannot restore the shad to its former peak of abundance.
Resumo:
Esta dissertação analisa a política externa brasileira contemporânea pelo prisma do ingresso do Brasil no G-20, a mais importante estrutura de governança global a se confrontar com a crise financeira desde 2008. É antiga a busca por reconhecimento do país, como marca da identidade internacional brasileira. A pesquisa avalia se o papel do Brasil no G-20 sinaliza o status de global player pelo entendimento teórico das escalas nas relações internacionais, em que a política externa, ao alterar sua escala, pode afetar o comportamento do agente estatal em diferentes agendas. Usando os conceitos de papel, status, identidade e reconhecimento, são analisadas as diferentes identidades internacionais do Brasil nas escalas regionais, Sul Global e internacional. O G-20 é tratado como uma instituição social, em que processos de socialização podem afetar o comportamento do Brasil entre os membros do fórum e fora dele. No G-20, o Brasil já demostrou que é susceptível aos processos de socialização por não confrontar agressivamente com as dinâmicas de poder do status quo, e por comprovar que o país valoriza seu lugar como um insider na mesa de negociações. Foi assim que o Brasil chegou a um marco nas projeções de poder e identidade no G-20. No sistema internacional, entretanto, o Brasil não alcançou o status de global player, devido aos conflituosos papéis que o país assume em sua região, no Sul Global e internacionalmente, além de suas capacidades moderadas de poder material.
Resumo:
Summer flounder (Paralichthys dentatus) is one of the most economically and ecologically important estuarine-dependent species in the northeastern United States. The status of the population is currently a topic of controversy. Our goal was to assess the potential of using larval abundance at ingress as another fishery independent measure of spawning stock biomass or recruitment. Weekly long-term ichthyoplankton time series were analyzed from Little Egg Inlet, New Jersey (1989–2006) and Beaufort Inlet, North Carolina (1986–2004). Mean size-at-ingress and stage were similar between sites, whereas timing of ingress and abundance at ingress were not similar. Ingress primarily occurred during the fall at Little Egg Inlet and the winter at Beaufort Inlet. These findings agree with those from earlier studies in which at least two stocks (one north and one south of Cape Hatteras) were identified with different spawning periods. Larval abundance at Little Egg Inlet has increased since the late 1990s and most individuals now enter the estuary earlier during the season of ingress. Abundance at Little Egg Inlet was correlated with an increase in spawning stock biomass, presumably because spawning by larger, more abundant fish during the late 1990s and early 2000s provided increased larval supply, at least in some years. Larval abundance at ingress at Beaufort Inlet was not correlated with spawning stock biomass or with larval abundance at ingress at Little Egg Inlet, further supporting the hypothesis of at least two stocks. Larval abundance at Little Egg Inlet could be used as a fishery-independent index of spawning stock size north of Cape Hatteras in future stock assessments. Larval occurrence at Beaufort Inlet may provide information on the abundance of the stock south of Cape Hatteras, but additional stock assessment work is required.
Resumo:
The efforts made to develop RNAi-based therapies have led to productive research in the field of infections in humans, such as hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), human cytomegalovirus (HCMV), herpetic keratitis, human papillomavirus, or influenza virus. Naked RNAi molecules are rapidly digested by nucleases in the serum, and due to their negative surface charge, entry into the cell cytoplasm is also hampered, which makes necessary the use of delivery systems to exploit the full potential of RNAi therapeutics. Lipid nanoparticles (LNP) represent one of the most widely used delivery systems for in vivo application of RNAi due to their relative safety and simplicity of production, joint with the enhanced payload and protection of encapsulated RNAs. Moreover, LNP may be functionalized to reach target cells, and they may be used to combine RNAi molecules with conventional drug substances to reduce resistance or improve efficiency. This review features the current application of LNP in RNAi mediated therapy against viral infections and aims to explore possible future lines of action in this field.