1,632 research outputs found

    Targeting Conservation Investments in Heterogeneous Landscapes: A distance function approach and application to watershed management

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    To achieve a given level of an environmental amenity at least cost, decision-makers must integrate information about spatially variable biophysical and economic conditions. Although the biophysical attributes that contribute to supplying an environmental amenity are often known, the way in which these attributes interact to produce the amenity is often unknown. Given the difficulty in converting multiple attributes into a unidimensional physical measure of an environmental amenity (e.g., habitat quality), analyses in the academic literature tend to use a single biophysical attribute as a proxy for the environmental amenity (e.g., species richness). A narrow focus on a single attribute, however, fails to consider the full range of biophysical attributes that are critical to the supply of an environmental amenity. Drawing on the production efficiency literature, we introduce an alternative conservation targeting approach that relies on distance functions to cost-efficiently allocate conservation funds across a spatially heterogeneous landscape. An approach based on distance functions has the advantage of not requiring a parametric specification of the amenity function (or cost function), but rather only requiring that the decision-maker identify important biophysical and economic attributes. We apply the distance-function approach empirically to an increasingly common, but little studied, conservation initiative: conservation contracting for water quality objectives. The contract portfolios derived from the distance-function application have many desirable properties, including intuitive appeal, robust performance across plausible parametric amenity measures, and the generation of ranking measures that can be easily used by field practitioners in complex decision-making environments that cannot be completely modeled. Working Paper # 2002-01

    Private finance for the delivery of school projects in England

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    This paper analyses the use of the private finance initiative (PFI) approach to deliver school projects in England. The findings are based on case-study research in the Building Schools for the Future scheme (BSF), the largest single capital investment in SO years to rebuild and renew all of England's secondary schools. Up to half of the school infrastructure is to be procured by PFI contracts. A major concern has been the high cost associated with PFI procurement and any subsequent changes to scope. Furthermore, in some cases PFI-funded schools have been closed soon after completion; at great cost to the public sector. The aim of this research was therefore to understand the underlying reasons for these problems. The main conclusion is that the difficulties in BSF arise from not sorting out strategic issues and instituting appropriate organisational frameworks before engaging the private sector. The result of this is a lack of clarity about the long-term needs and end user aspirations. A brief outline of current programme management methods is given and it is suggested that this might be integral to the successful delivery of schools using private finance. A clear strategic vision that cascades into projects via programmes will ensure that the school infrastructure is appropriate for the anticipated strategic benefits and is aligned to the overall service delivery ambitions

    Invasive Plants: Changing the Landscape of America

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    In the 1950s, the American public became aware that certain chemicals endanger human health and the environment. In response to this threat, new rules and regulations regarding chemical manufacture, use, and disposal were developed under state and federal law. Today, the public has a much better understanding of the chemical pollution problem and generally supports management efforts. The 1990s have brought us face to face with another serious environmental threat: The invasion of the American landscape by aggressive nonnative plants. While farmers have always fought a battle with weeds in crops, invasion of these and other formerly weed-free lands has increased exponentially in recent decades. Because they often look no different than native plants and animals, nonnative plants can become established and cause serious economic and ecological damage before they are detected. Since the 1960s, the United States has made dramatic strides in most areas of environmental protection. However, at the same time, biological invasions, which in part created the need for pesticides, continue in spite of federal efforts to exclude foreign pests from other countries. In recent years, this silent invasion has alarmed scientists worldwide and prompted federal officials in the United States to work together to address the problem. Environmentally sound approaches and techniques for weed prevention and early control are necessary prerequisites in the battle against invasive plants

    Management of the Houtman Abrohlos System. A draft review 2007 - 2017

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    This review contains a brief description of the Abrolhos System and its special values. It also states the goal and principal objectives for management during the next ten years (2006-2016), along with updated strategies to achieve these objectives. The document succinctly outlines the direction for multiple use management of the Houtman Abrolhos Islands as determined by the Abrolhos Islands Management Advisory Committee (AIMAC). The Committee’s role is to advise the Minister for Fisheries on management of the Abrolhos Islands and the Abrolhos Islands Fish Habitat Protection Area

    An Adverse Outcome Pathway for Sensitization of the Respiratory Tract by Low-Molecular-Weight Chemicals: Building Evidence to Support the Utility of In Vitro and In Silico Methods in a Regulatory Context

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    Sensitization of the respiratory tract is an important occupational health challenge, and understanding the mechanistic basis of this effect is necessary to support the development of toxicological tools to detect chemicals that may cause it. Here we use the adverse outcome pathway (AOP) framework to organize information that may better inform our understanding of sensitization of the respiratory tract, building on a previously published skin sensitization AOP, relying on literature evidence linked to low-molecular-weight organic chemicals and excluding other known respiratory sensitizers acting via different molecular initiating events. The established key events (KEs) are as follows: (1) covalent binding of chemicals to proteins, (2) activation of cellular danger signals (inflammatory cytokines and chemokines and cytoprotective gene pathways), (3) dendritic cell activation and migration, (4) activation, proliferation, and polarization of T cells, and (5) sensitization of the respiratory tract. These events mirror the skin sensitization AOP but with specific differences. For example, there is some evidence that respiratory sensitizers bind preferentially to lysine moieties, whereas skin sensitizers bind to both cysteine and lysine. Furthermore, exposure to respiratory sensitizers seems to result in cell behavior for KEs 2 and 3, as well as the effector T cell response, in general skewing toward cytokine secretions predominantly associated with T helper 2 (Th2) response. Knowledge gaps include the lack of understanding of which KE(s) drive the Th2 polarization. The construction of this AOP may provide insight into predictive tests that would in combination support the discrimination of respiratory-sensitizing from non- and skin-sensitizing chemicals, a clear regulatory need

    The impact of early hypoglycemia and blood glucose variability on outcome in critical illness

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    INTRODUCTION: In critical illness, the association of hypoglycemia, blood glucose (BG) variability and outcome are not well understood. We describe the incidence, clinical factors and outcomes associated with an early hypoglycemia and BG variability in critically ill patients. METHODS: Retrospective interrogation of prospectively collected data from the Australia New Zealand Intensive Care Society Adult Patient Database on 66184 adult admissions to 24 intensive care units (ICUs) from 1 January 2000 to 31 December 2005. Primary exposure was hypoglycemia (BG or= 12.0 mmol/L) within 24 hours of admission. Primary outcome was all-cause mortality. RESULTS: The cumulative incidence of hypoglycemia and BG variability were 13.8% (95% confidence interval (CI) = 13.5 to 14.0; n = 9122) and 2.9% (95%CI = 2.8 to 3.0, n = 1913), respectively. Several clinical factors were associated with both hypoglycemia and BG variability including: co-morbid disease (P < 0.001), non-elective admissions (P < 0.001), higher illness severity (P < 0.001), and primary septic diagnosis (P < 0.001). Hypoglycemia was associated with greater odds of adjusted ICU (odds ratio (OR) = 1.41, 95% CI = 1.31 to 1.54) and hospital death (OR = 1.36, 95% CI = 1.27 to 1.46). Hypoglycemia severity was associated with 'dose-response' increases in mortality. BG variability was associated with greater odds of adjusted ICU (1.5, 95% CI = 1.4 to 1.6) and hospital (1.4, 95% CI = 1.3 to 1.5) mortality, when compared with either hypoglycemia only or neither. CONCLUSIONS: In critically ill patients, both early hypoglycemia and early variability in BG are relatively common, and independently portend an increased risk for mortality
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