800 resultados para ecological risk assessment


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At the start of the industrial revolution (circa 1750) the atmospheric concentration of carbon dioxide (CO2) was around 280 ppm. Since that time the burning of fossil fuel, together with other industrial processes such as cement manufacture and changing land use, has increased this value to 400 ppm, for the first time in over 3 million years. With CO2 being a potent greenhouse gas, the consequence of this rise for global temperatures has been dramatic, and not only for air temperatures. Global Sea Surface Temperature (SST) has warmed by 0.4–0.8 °C during the last century, although regional differences are evident (IPCC, 2007). This rise in atmospheric CO2 levels and the resulting global warming to some extent has been ameliorated by the oceanic uptake of around one quarter of the anthropogenic CO2 emissions (Sabine et al., 2004). Initially this was thought to be having little or no impact on ocean chemistry due to the capacity of the ocean’s carbonate buffering system to neutralise the acidity caused when CO2 dissolves in seawater. However, this assumption was challenged by Caldeira and Wickett (2005) who used model predictions to show that the rate at which carbonate buffering can act was far too slow to moderate significant changes to oceanic chemistry over the next few centuries. Their model predicted that since pre-industrial times, ocean surface water pH had fallen by 0.1 pH unit, indicating a 30% increase in the concentration of H+ ions. Their model also showed that the pH of surface waters could fall by up to 0.4 units before 2100, driven by continued and unabated utilisation of fossil fuels. Alongside increasing levels of dissolved CO2 and H+ (reduced pH) an increase in bicarbonate ions together with a decrease in carbonate ions occurs. These chemical changes are now collectively recognised as “ocean acidification”. Concern now stems from the knowledge that concentrations of H+, CO2, bicarbonate and carbonate ions impact upon many important physiological processes vital to maintaining health and function in marine organisms. Additionally, species have evolved under conditions where the carbonate system has remained relatively stable for millions of years, rendering them with potentially reduced capacity to adapt to this rapid change. Evidence suggests that, whilst the impact of ocean acidification is complex, when considered alongside ocean warming the net effect on the health and productivity of the oceans will be detrimental.

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In this paper we describe how an evidential-reasoner can be used as a component of risk assessment of engineering projects using a direct way of reasoning. Guan & Bell (1991) introduced this method by using the mass functions to express rule strengths. Mass functions are also used to express data strengths. The data and rule strengths are combined to get a mass distribution for each rule; i.e., the first half of our reasoning process. Then we combine the prior mass and the evidence from the different rules; i.e., the second half of the reasoning process. Finally, belief intervals are calculated to help in identifying the risks. We apply our evidential-reasoner on an engineering project and the results demonstrate the feasibility and applicability of this system in this environment.

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The purpose of this study is to develop a decision making system to evaluate the risks in E-Commerce (EC) projects. Competitive software businesses have the critical task of assessing the risk in the software system development life cycle. This can be conducted on the basis of conventional probabilities, but limited appropriate information is available and so a complete set of probabilities is not available. In such problems, where the analysis is highly subjective and related to vague, incomplete, uncertain or inexact information, the Dempster-Shafer (DS) theory of evidence offers a potential advantage. We use a direct way of reasoning in a single step (i.e., extended DS theory) to develop a decision making system to evaluate the risk in EC projects. This consists of five stages 1) establishing knowledge base and setting rule strengths, 2) collecting evidence and data, 3) determining evidence and rule strength to a mass distribution for each rule; i.e., the first half of a single step reasoning process, 4) combining prior mass and different rules; i.e., the second half of the single step reasoning process, 5) finally, evaluating the belief interval for the best support decision of EC project. We test the system by using potential risk factors associated with EC development and the results indicate that the system is promising way of assisting an EC project manager in identifying potential risk factors and the corresponding project risks.

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The bovine spongiform encephalopathy (BSE) outbreak in the United Kingdom is regarded as one of the worst public policy crises the British government has experienced during the postwar era. In material terms, it has led to the slaughter of 3.3 million cattle and estimated economic losses of £3.7 billion. In administrative terms, the crisis brought about the dissolution of the Ministry of Agriculture, Fisheries and Food. This article examines the istitutional context in which decisions about the scientific evidence on BSE were made. The authors argue that a centralized system in which government agencies control science for government is inherently vulnerable to alliances of experts and interest groups that undermine the credible assessment of public health and safety risks. Specific societal conditions may encourage risk-opportunistic behavior among policy makers that is conducive to delays and inaction until such time as the evidence of a health risk becomes overwhelming.

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The issue of inherited disorders in pedigree dogs is not a recent phenomenon and reports of suspected genetic defects associated with breeding practices date back to Charles Darwin's time. In recent years, much information on the array of inherited defects has been assimilated and the true extent of the problem has come to light. Historically, the direction of research funding in the field of canine genetic disease has been largely influenced by the potential transferability of findings to human medicine, economic benefit and importance of dogs for working purposes. More recently, the argument for a more canine welfare-orientated approach has been made, targeting research efforts at the alleviation of the most suffering in the greatest number of animals.

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This article examines recent research on risk assessment and probation practice in Ireland and relates the findings to the ongoing debate regarding risk management practices in probation. The piece discusses current theoretical arguments on the influence of risk in criminal justice and outlines the impact of risk discourse on probation practice in Ireland and England and Wales. Using a mix of qualitative and quantitative methods, Irish probation officers’ attitudes are examined in order to highlight key issues facing probation officers when making risk decisions. These findings are compared and contrasted to other research results from England and Wales. All the conclusions identify both positive and negative consequences of adopting risk tools and point to the continued salience of clinical judgment over actuarial methods of risk assessment. It is argued that the research highlights the role of ‘resistance’ by criminal justice professionals in mediating the effects of the ‘new penology’ at the level of implementation. The idea of resistance holds particular relevance for probation practice in Ireland where professional discretion is maintained within the National Standards framework. Despite this, to date there has been an uncritical approach taken to risk assessment which may ignore the dangers of risk inflation/deflation and the need to take into account local factors in assessing risk of reoffending

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A field survey was conducted to investigate the contamination of potentially toxic elements (PTEs) arsenic (As), lead (Pb), chromium (Cr), and nickel (Ni) in Tanzanian agricultural soils and to evaluate their uptake and translocation in maize as proxy to the safety of maize used for human and animal consumption. Soils and maize tissues were sampled from 40 farms in Tanzania and analyzed using inductively coupled plasma-mass spectrometry in the United Kingdom. The results showed high levels of PTEs in both soils and maize tissues above the recommended limits. Nickel levels of up to 34.4 and 56.9mgkg(-1) respectively were found in some maize shoots and grains from several districts. Also, high Pb levels >0.2mgkg(-1) were found in some grains. The grains and shoots with high levels of Ni and Pb are unfit for human and animal consumption. Concentrations of individual elements in maize tissues and soils did not correlate and showed differences in uptake and translocation. However, Ni showed a more efficient transfer from soils to shoots than As, Pb and Cr. Transfer of Cr and Ni from shoots to grains was higher than other elements, implying that whatever amount is assimilated in maize shoots is efficiently mobilized and transferred to grains. Thus, the study recommended to the public to stop consuming and feeding their animals maize with high levels of PTEs for their safety.

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Risk is defined as a situation involving exposure to danger. Risk assessment by nature characterises the probability of a negative event occurring and quantifies the consequences of such an event. Risk assessment is increasingly being used in the field of animal welfare as a means of drawing comparisons between multiple welfare problems within and between species and identifying those that should be prioritised by policy-makers, either because they affect a large proportion of the population or because they have particularly severe consequences for those affected. The assessment of risk is typically based on three fundamental factors: intensity of consequences, duration affected by consequences and prevalence. However, it has been recognised that these factors alone do not give a complete picture of a hazard and its associated consequences. Rather, to get a complete picture, it is important to also consider information about the hazard itself: probability of exposure to the hazard and duration of exposure to the hazard. The method has been applied to a variety of farmed species (eg poultry, dairy cows, farmed fish), investigating housing, husbandry and slaughter procedures, as well as companion animals, where it has been used to compare inherited defects in pedigree dogs and horses. To what extent can we trust current risk assessment methods to get the priorities straight? How should we interpret the results produced by such assessments? Here, the potential difficulties and pitfalls of the welfare risk assessment method will be discussed: (i) the assumption that welfare hazards are independent; (ii) the problem of quantifying the model parameters; and (iii) assessing and incorporating variability and uncertainty into welfare risk assessments. © 2012 Universities Federation for Animal Welfare.