70 resultados para Radon mitigation
Resumo:
In this paper we give first account of a simple analysis tool for modeling temporal compression for automatic mitigation of multipath induced intersymbol interference through the use of active phase conjugation (APC) technique. The temporal compression characteristics of an APC system is analyzed using a simple discrete channel model, and numerical results are provided to justify the theoretical findings.
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Mitigation of diffuse nutrient and sediment delivery to streams requires successful identification andmanagement of critical source areas within catchments. Approaches to predicting high risk areas forsediment loss have typically relied on structural drivers of connectivity and risk, with little considera-tion given to process driven water quality responses. To assess the applicability of structural metrics topredict critical source areas, geochemical tracing of land use sources was conducted in three headwateragricultural catchments in Co. Down and Co. Louth, Ireland, within a Monte Carlo framework. Outputswere applied to the inverse optimisation of a connectivity model, based on LiDAR DEM data, to assess theefficacy of land use risk weightings to predict sediment source contributions over the 18 month studyperiod in the Louth Upper, Louth Lower and Down catchments. Results of the study indicated sedimentproportions over the study period varied from 6 to 10%, 84 to 87%, 4%, and 2 to 3% for the Down Catch-ment, 79 to 85%, 9 to 17%, 1 to 3% and 2 to 3% in the Louth Upper and 2 to 3%, 79 to 85%, 10 to 17%and 2 to 3% in the Louth Lower for arable, channel bank, grassland, and woodland sources, respectively.Optimised land use risk weightings for each sampling period showed that at the larger catchment scale,no variation in median land use weightings were required to predict land use contributions. However,for the two smaller study catchments, variation in median risk weightings was considerable, which mayindicate the importance of functional connectivity processes at this spatial scale. In all instances, arableland consistently generated the highest risk of sediment loss across all catchments and sampling times.This study documents some of the first data on sediment provenance in Ireland and indicates the needfor cautious consideration of land use as a tool to predict critical source areas at the headwater scale
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This paper examines the ability of the doubly fed induction generator (DFIG) to deliver multiple reactive power objectives during variable wind conditions. The reactive power requirement is decomposed based on various control objectives (e.g. power factor control, voltage control, loss minimisation, and flicker mitigation) defined around different time frames (i.e. seconds, minutes, and hourly), and the control reference is generated by aggregating the individual reactive power requirement for each control strategy. A novel coordinated controller is implemented for the rotor-side converter and the grid-side converter considering their capability curves and illustrating that it can effectively utilise the aggregated DFIG reactive power capability for system performance enhancement. The performance of the multi-objective strategy is examined for a range of wind and network conditions, and it is shown that for the majority of the scenarios, more than 92% of the main control objective can be achieved while introducing the integrated flicker control scheme with the main reactive power control scheme. Therefore, optimal control coordination across the different control strategies can maximise the availability of ancillary services from DFIG-based wind farms without additional dynamic reactive power devices being installed in power networks.
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The recent growth in bioenergy crop cultivation, stimulated by the need to implement measures to reduce net CO emissions, is driving major land-use changes with consequences for biodiversity and ecosystem service provision. Although the type of bioenergy crop and its associated management is likely to affect biodiversity at the local (field) scale, landscape context and its interaction with crop type may also influence biodiversity on farms. In this study, we assessed the impact of replacing conventional agricultural crops with two model bioenergy crops (either oilseed rape Brassica napus or Miscanthus × giganteus) on vascular plant, bumblebee, solitary bee, hoverfly and carabid beetle richness, diversity and abundance in 50 sites in Ireland. We assessed whether within-field biodiversity was also related to surrounding landscape structure. We found that local- and landscape-scale variables correlated with biodiversity in these agricultural landscapes. Overall, the differences between the bioenergy crops and the conventional crops on farmland biodiversity were mostly positive (e.g. higher vascular plant richness in Miscanthus planted on former conventional tillage, higher solitary bee abundance and richness in Miscanthus and oilseed rape compared with conventional crops) or neutral (e.g. no differences between crop types for hoverflies and bumblebees). We showed that these crop type effects were independent of (i.e. no interactions with) the surrounding landscape composition and configuration. However, surrounding landscape context did relate to biodiversity in these farms, negatively for carabid beetles and positively for hoverflies. Although we conclude that the bioenergy crops compared favourably with conventional crops in terms of biodiversity of the taxa studied at the field scale, the effects of large-scale planting in these landscapes could result in very different impacts. Maintaining ecosystem functioning and the delivery of ecosystem services will require a greater understanding of impacts at the landscape scale to ensure the sustainable development of climate change mitigation measures.
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Residues of veterinary medicines are a food safety issue regulated by European legislation. The occurrence of animal diseases necessitating application of veterinary medicines is significantly affected by global and local climate changes. This review assesses potential impacts of climate change on residues in food produced on the island of Ireland. Use of various classes of veterinary drugs in light of predicted local climate change is reviewed with particular emphasis on anthelmintic drugs and consideration is given to residues accumulating in the environment. Veterinary medicine use is predicted to increase as disease burdens increase due to varied climate effects. Locally relevant mitigation and adaptation strategies are suggested to ensure climate change does not adversely affect food safety via increasing drug residues.
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In recent years, the issue of life expectancy has become of upmost importance to pension providers, insurance companies and the government bodies in the developed world. Significant and consistent improvements in mortality rates and, hence, life expectancy have led to unprecedented increases in the cost of providing for older ages. This has resulted in an explosion of stochastic mortality models forecasting trends in mortality data in order to anticipate future life expectancy and, hence, quantify the costs of providing for future aging populations. Many stochastic models of mortality rates identify linear trends in mortality rates by time, age and cohort, and forecast these trends into the future using standard statistical methods. The modeling approaches used failed to capture the effects of any structural change in the trend and, thus, potentially produced incorrect forecasts of future mortality rates. In this paper, we look at a range of leading stochastic models of mortality and test for structural breaks in the trend time series.
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Mobile malware has continued to grow at an alarming rate despite on-going mitigation efforts. This has been much more prevalent on Android due to being an open platform that is rapidly overtaking other competing platforms in the mobile smart devices market. Recently, a new generation of Android malware families has emerged with advanced evasion capabilities which make them much more difficult to detect using conventional methods. This paper proposes and investigates a parallel machine learning based classification approach for early detection of Android malware. Using real malware samples and benign applications, a composite classification model is developed from parallel combination of heterogeneous classifiers. The empirical evaluation of the model under different combination schemes demonstrates its efficacy and potential to improve detection accuracy. More importantly, by utilizing several classifiers with diverse characteristics, their strengths can be harnessed not only for enhanced Android malware detection but also quicker white box analysis by means of the more interpretable constituent classifiers.
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The vulnerability of coastal areas to associated hazards is increasing due to population growth, development pressure and climate change. It is incumbent on coastal governance regimes to address the vulnerability of coastal inhabitants to these hazards. This is especially so at the local level where development planning and control has a direct impact on the vulnerability of coastal communities. To reduce the vulnerability of coastal populations, risk mitigation and adaptation strategies need to be built into local spatial planning processes. Local government, however, operates within a complex hierarchal governance framework which may promote or limit particular actions. It is important, therefore, to understand how local coastal planning practices are shaped by national and supranational entities. Local governments also have to respond to the demands of local populations. Consequently, it is important to understand local populations’ perceptions of coastal risk and its management. Adopting an in-depth study of coastal planning in County Mayo, Ireland, this paper evaluates: (a) how European and national policies and legislation shape coastal risk management at local level; (b) the incorporation of risk management strategies into local plans; and (c) local perception of coastal risks and risk management. Despite a strong steer from supranational and national legislation and policy, statutory local plans are found to be lacking in appropriate risk mitigation or adaptation strategies. Local residents appear to be lulled into a sense of complacency towards these risks because of the low level of attention afforded to them by the local planning authorities. To avoid potentially disastrous consequences for local residents and businesses, it is imperative that this situation is redressed urgently. Based on our analysis, we recommend: the development and implementation of a national ICZM strategy, supported by detailed local ICZM plans; and obliging local government to address known risks in their plans rather than defer them to project level decision making.
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The availability of electricity is fundamental to modern society. It is at the top of the list of critical infrastructures and its interruption can have severe consequences. This highly important system is now evolving to become more reliable, efficient, and clean. This evolving infrastructure has become known as the smart grid; and these future smart grid systems will rely heavily on ICT. This infrastructure will require many servers and due to the nature of the grid, many of these systems will be geographically diverse requiring communication links. At the heart of this ICT infrastructure will be security. At each level of the smart grid from smart metering right through to remote sensing and control networks, security will be a key factor for system design consideration. With an increased number of ICT systems in place the security risk also increases. In this paper the authors discuss the changing nature of security in relation to the smart grid by looking at the move from legacy systems to more modern smart grid systems. The potential planes of attack for future smart grid systems are identified, and the general anatomy of a cyber-attack is presented. The authors then introduce the various threat levels of different types of attack and the mitigation techniques that could be put in place for each. Finally, the authors' introduce a Phasor Measurement Unit (PMU) communication system (operated by the authors) that can be used as a test-bed for some of the proposed future security research.
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Climate change during the last five decades has impacted significantly on natural ecosystems and the rate of current climate change is of great concern among conservation biologists. Species Distribution Models (SDMs) have been used widely to project changes in species’ bioclimatic envelopes under future climate scenarios. Here, we aimed to advance this technique by assessing future changes in the bioclimatic envelopes of an entire mammalian order, the Lagomorpha, using a novel framework for model validation based jointly on subjective expert evaluation and objective model evaluation statistics. SDMs were built using climatic, topographical and habitat variables for all 87 lagomorph species under past and current climate scenarios. Expert evaluation and Kappa values were used to validate past and current models and only those deemed ‘modellable’ within our framework were projected under future climate scenarios (58 species). Phylogenetically-controlled regressions were used to test whether species traits correlated with predicted responses to climate change. Climate change is likely to impact more than two-thirds of lagomorph species, with leporids (rabbits, hares and jackrabbits) likely to undertake poleward shifts with little overall change in range extent, whilst pikas are likely to show extreme shifts to higher altitudes associated with marked range declines, including the likely extinction of Kozlov’s Pika (Ochotona koslowi). Smaller-bodied species were more likely to exhibit range contractions and elevational increases, but showing little poleward movement, and fecund species were more likely to shift latitudinally and elevationally. Our results suggest that species traits may be important indicators of future climate change and we believe multi-species approaches, as demonstrated here, are likely to lead to more effective mitigation measures and conservation management. We strongly advocate studies minimising data gaps in our knowledge of the Order, specifically collecting more specimens for biodiversity archives and targeting data deficient geographic regions.
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The shore crab, Carcinus maenas, is recognized as a voracious predator of blue mussels, Mytilus edulis, having the potential to greatly reduce stocks in the benthic cultivation industry. As a consequence, baited crab pots are often deployed on and around cultivated benthic mussel beds to trap and remove crabs, in an attempt to reduce predatory pressure. Little is known about how C. maenas behaves around crab pots, but for many other crustacean fisheries, the trapping efficiency of pots is often low. Crabs may be attracted towards but not enter pots, instead feeding on cultivated mussels outside pots on the surrounding substratum. We tested whether the rate of loss of mussels attached to plates differed in areas next to baited pots compared with unbaited pots and to areas without any pots, at two sea loughs (60 km apart) in Northern Ireland. In Strangford Lough, more mussels were lost from plates next to baited pots than the other treatments. In Carlingford Lough, however, we found no difference in the number of mussels lost from plates in any treatment. This difference could be attributed to the different assemblages of mobile benthic predators at the two loughs. The presence of the starfish Asterias rubens, which was absent from experimental sites in Carlingford Lough, was thought to be responsible for increased predation rates near baited pots in Strangford. It is, therefore, important to consider local predator communities when deploying crab pots as a predator mitigation technique to ensure predation rates are in fact reduced and not enhanced. This study is of relevance not only to attempts to limit predation on commercial stocks of benthic cultivated mussels but also in situations where baited traps are deployed close to species vulnerable to mobile benthic predators.
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Child undernutrition, a form of malnutrition, is a major public health burden in developing countries. Supplementation interventions targeting the major micronutrient deficiencies have only reduced the burden of child undernutrition to a certain extent, indicating that there are other underlying determinants that need addressed. Aflatoxin exposure, which is also highly prevalent in developing countries, may be considered to be an aggravating factor for child undernutrition. Increasing evidence suggests that aflatoxin exposure can occur in any stage of life including in utero through a trans-placental pathway and in early childhood (through contaminated weaning food and family food). Early life exposure to aflatoxin is associated with adverse effects on low birth weight, stunting, immune suppression and liver function damage. The mechanisms underlying impaired growth and aflatoxin exposure are still unclear but intestinal function damage, reduced immune function and alteration in the insulin-like growth factor axis caused by liver damage, are suggested hypotheses. Given the fact that both aflatoxin and child undernutrition are common in sub-Saharan Africa, effective interventions aimed at reducing undernutrition cannot be satisfactorily achieved until the interactive relationship between aflatoxin and child undernutrition is clearly understood, and an aflatoxin mitigation strategy has taken effect in those vulnerable mothers and children.
Resumo:
Inner city developments are a common feature within many urban environments. Where these construction sites are not managed effectively, they can negatively impact their surrounding community. The aim of this paper is to identify and document, in an urban context, the numerous issues encounter and subsequent strategies adopted by on-site contractors and local people, in the mitigation of factors which negatively impact their surrounding community. The objectives in achieving this aim are to identify what effect, if any, an urban construction site has on its surrounding environment, the issues and resulting strategies adopted by contractors on the factors identified, and also what measures are put in place to minimise such disturbances to the local community. In order to meet the requirements, a mixed methodology is adopted culminating in a literature review, case study analysis, contractor and community interviews, concluding in the development of two specific questions for both perspectives in question. The data is assessed using severity indices based on mean testing in the development of key findings. The results indicate that the main forms of disturbance to the local community from an urban development include noise, dust and traffic congestion. With respect to a contractor on-site, the key issues include damaging surrounding buildings, noise control and off-site parking. The resulting strategies identified in the mitigation of such issues include the implementation of noise and dust containment measures and minimising disruption to local infrastructure. It is envisaged that the results of this study will provide contractors operating in such environments, with the required information which can assist in minimising disruption and therefore, avoiding disputes with the local community members. By consulting with and surveying those most affected, this research will illustrate to on-site management, the difficulties faced by those who accommodate such developments within their living environment.
Resumo:
Twentieth century public health initiatives have been crucially informed by perceptions and constructions of risk. Notions of risk identification, assessment and mitigation have guided political and institutional actions even before these concepts became an explicit part of the language of public administration and policy making. Past analyses investigating the link between risk perceptions and public health are relatively rare, and where researchers have investigated this nexus, it has typically been assumed that the collective identification of health risks has led to progressive improvements in public health activities.
Risk and the Politics of Public Health addresses this gap by presenting a detailed critical historical analysis of the evolution of risk thinking within medical and health related discourses. Grouped around the four core themes of 'immigration', 'race', 'armed conflict' and 'detention and prevention' this book highlights the innovative capacity of risk related concepts as well as their vulnerability to the dysfunctional effects of dominant social ideologies. Risk and the Politics of Public Health is an essential reference for those who seek to understand the interplay of concepts of risk and public health throughout history as well as those who wish to gain a critical understanding of the social dynamics which have underpinned, and continue to underpin, this complex interaction.
Resumo:
The impact of invasive bank vole (Myodes glareolus) and greater white-toothed shrew (Crocidura russula) on indigenous Irish small mammals, varies with season and habitat. We caught bank voles in deciduous woodland, young coniferous plantations and open habitats such as rank grass. The greater white-toothed shrew was absent from deciduous woods and plantations but did use open habitats with low level cover in addition to field margins. Numbers of both invasive species in field margins during summer were higher than in the previous spring. The indigenous wood mouse (Apodemus sylvaticus) and pygmy shrew (Sorex minutus), differed in degrees of negative response to invasive species. Wood mice with bank voles in hedgerows had reduced recruitment and lower peak abundance. This effect was less extreme where both invasive species were present. Wood mice numbers along field margins and open habitats were significantly depressed by the presence of the bank vole with no such effect in deciduous woodland or coniferous plantations. Summer recruitment in pygmy shrews was reduced in hedgerows with bank voles. Where greater white-toothed shrew was present, the pygmy shrew was entirely absent from field margins. Species replacement due to invasive small mammals is occurring in their major habitat i.e. field margins and open habitats where there is good ground cover. Pygmy shrew will probably disappear from these habitats throughout Ireland. Wood mice and possibly pygmy shrew may survive in deciduous woodland and conifer plantations. Mitigation of impacts of invasive species should include expansion of woodland in which native species can survive.