IP network usage accounting, parte 2: accounting system

O controlo de banda larga é um conceito importante quando lidamos com redes de larga escala. Os ISPs precisam de garantir disponibilidade e qualidade de serviço a todos os clientes, enquanto garantem que a rede como um todo não fica mais lenta. Para garantir isto, é necessário que os ISPs recolham dados de tráfego, analisem-nos e usem-nos para definir a velocidade de banda larga de cada cliente. A NOS Madeira implementou, durante vários anos, um sistema semelhante. No entanto, este sistema encontrava-se obsoleto, sendo necessário construir um novo, totalmente de raíz. Entre as limitações encontrava-se a impossibilidade de alterar os algoritmos de análise de tráfego, fraca integração com os serviços de gestão de rede da NOS Madeira e reduzida escalabilidade e modularidade. O sistema IP Network Usage Accounting é a resposta a estes problemas. Este projeto foca-se no desenvolvimento do subsistema Accounting System, o segundo dos três subsistemas que compõem o sistema IP Network Usage Accounting. Este subsistema, implementado com sucesso e atualmente em produção na NOS Madeira, é responsável por analisar os dados referidos acima e usar os resultados dessa análise para direcionar a disponibilidade de banda larga, de acordo com o uso da rede de cada cliente.

Mercury in soils and sediments from gold mining liabilities in Southern Amazonia

The 1980-1990 Amazonian gold rush left an enormous liability that increasingly has been substituted by developing fish aquaculture. This work aimed at the identification of the mercury levels in the environment, associated with fish farms located in the North of Mato Grosso State, Southern Amazon. Sediment and soil samples were analyzed for total organic carbon and total mercury. Results indicate that the chemical characteristics of the sediment largely depend on the management procedures of the fish pond (liming, fish food used and fish population). The soils presented relatively low concentrations when compared with other data from the literature.

Dehydromonocrotaline inhibits mitochondrial complex 1. A potential mechanism accounting for hepatotoxicity of monocrotaline

Monocrotaline is a pyrrolizidine alkaloid present in plants of the Crotalaria species, which causes cytotoxicity and genotoxicity, including hepatotoxicity in animals and humans. It is metabolized by cytochrome P-450 in the liver to the alkylating agent dehydromonocrotaline. We evaluated the effects of monocrotaline and its metabolite on respiration, membrane potential and ATP levels in isolated rat liver mitochondria, and on respiratory chain complex I NADH oxidase activity in submitochondrial particles. Dehydromonocrotaline, but not the parent compound, showed a concentration-dependent inhibition of glutamate/malate-supported state 3 respiration (respiratory chain complex 1), but did not affect succinate-supported respiration (complex II). Only dehydromonocrotaline dissipated mitochondrial membrane potential, depleted ATP, and inhibited complex I NADH oxidase activity (IC50 = 62.06 mu M) through a non-competitive type of inhibition (K-I = 8.1 mu M). Therefore, dehydromonocrotaline is an inhibitor of the activity of respiratory chain complex I NADH oxidase, an action potentially accounting for the well-documented monocrotaline's hepatotoxicity to animals and humans. The mechanism probably involves change of the complex I conformation resulting from modification of cysteine thiol groups by the metabolite. (c) 2007 Elsevier Ltd. All rights reserved.

Comparing emergy accounting with well-known sustainability metrics: The case of Southern Cone Common Market, Mercosur

The quality and the power of human activities affect the external environment in different ways that can be measured and evaluated by means of several approaches and indicators. While the scientific community has been publishing several proposals for sustainable development indicators, there is still no consensus regarding the best approach to the use of these indicators and their reliability to measure sustainability. It is important, therefore, to question the effectiveness of sustainable development indicators in an effort to continue in the search for sustainability. This paper compares the results obtained with emergy accounting with five global Sustainability Metrics (SMs) proposed in the literature to verify if metrics are communicating coherent and similar information to guide decision makers towards sustainable development. Results obtained using emergy indices are discussed with the aid of emergy ternary diagrams. Metrics are confronted with emergy results, and the degree of variability among them is analyzed using a correlation matrix created for the Mercosur nations. The contrast of results clearly shows that metrics arrive at different interpretations about the sustainability of the nations studied, but also that some metrics may be grouped and used more prudently. Mercosur is presented as a case study to highlight and explain the discrepancies and similarities among Sustainability Metrics, and to expose the extent of emergy accounting. (C) 2010 Elsevier Ltd. All rights reserved.

The new era of carbon accounting: issues and implications for Latin American and Caribbean exports

Includes Bibliography

Accrual accounting and budgeting: key issues and recent developments

Includes bibliography

Report of the Workshop on Integrated Environmental and Economic Accounting

Includes bibliography

Renewable energy sources in Latin America and the Caribbean: situation and policy proposals

Includes bibliography