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Substantial Uncertainty (substantial + uncertainty)
Selected AbstractsObstacles to Bottom-Up Implementation of Marine Ecosystem ManagementCONSERVATION BIOLOGY, Issue 5 2008KIRSTEN E. EVANS manejo de ecosistemas; manejo marino basado en ecosistemas; participación de partes interesadas; planificación de la conservación Abstract:,Ecosystem management (EM) offers a means to address multiple threats to marine resources. Despite recognition of the importance of stakeholder involvement, most efforts to implement EM in marine systems are the product of top-down regulatory control. We describe a rare, stakeholder-driven attempt to implement EM from the bottom up in San Juan County, Washington (U.S.A.). A citizens advisory group led a 2-year, highly participatory effort to develop an ecosystem-based management plan, guided by a preexisting conservation-planning framework. A key innovation was to incorporate social dimensions by designating both sociocultural and biodiversity targets in the planning process. Multiple obstacles hindered implementation of EM in this setting. Despite using a surrogate scheme, the information-related transaction costs of planning were substantial: information deficits prevented assessment of some biodiversity targets and insufficient resources combined with information deficits prevented scientific assessment of the sociocultural targets. Substantial uncertainty, practical constraints to stakeholder involvement, and the existence of multiple, potentially conflicting, objectives increased negotiation-related costs. Although information deficits and uncertainty, coupled with underinvestment in the transaction costs of planning, could reduce the long-term effectiveness of the plan itself, the social capital and momentum developed through the planning process could yield unforeseeable future gains in protection of marine resources. The obstacles we identified here will require early and sustained attention in efforts to implement ecosystem management in other grassroots settings. Resumen:,El manejo de ecosistemas es un medio para abordar múltiples amenazas a los recursos marinos. No obstante el reconocimiento de la importancia de la participación de las partes interesadas, la mayoría de los esfuerzos para implementar el manejo de ecosistemas en sistemas marinos son producto del control normativo de arriba hacia abajo. Describimos un intento raro, conducido por las partes interesadas, por implementar el manejo del ecosistema de abajo hacia arriba en el Condado San Juan, Washington (E.U.A.). Un grupo consultivo de ciudadanos dirigió un esfuerzo altamente participativo para desarrollar un plan de manejo basado en el ecosistema, guiados por un marco de planificación de la conservación preexistente. Una innovación clave fue la incorporación de dimensiones sociales al incluir objetivos tanto socioculturales como de biodiversidad en el proceso de planificación. Múltiples obstáculos dificultaron la implementación del manejo del ecosistema en este escenario. No obstante que se utilizó un plan sustituto, los costos de transacción de la planificación relacionados con la información fueron mayores de lo que el grupo pudo superar: los déficits de información impidieron la evaluación de algunos objetivos de biodiversidad y la insuficiencia de recursos combinada con los déficits de información impidieron la evaluación científica de los objetivos socioculturales. Los costos relacionados con la negociación incrementaron por la incertidumbre, por limitaciones prácticas en la participación de partes interesadas y la existencia de objetivos múltiples, potencialmente conflictivos. Aunque los déficits de información y la incertidumbre, aunados con la baja inversión en los costos de transacción de la planificación, pudieran reducir la efectividad a largo plazo del plan mismo, el capital social y el ímpetu desarrollados durante el proceso de planificación podrían producir ganancias futuras imprevisibles para la protección de recursos marinos. Los obstáculos que identificamos aquí requerirán de atención temprana y sostenida en los esfuerzos para implementar el manejo de ecosistemas en otros escenarios de base popular. [source] Alpine flora dynamics , a critical review of responses to climate change in the Swedish Scandes since the early 1950sNORDIC JOURNAL OF BOTANY, Issue 4 2010Leif Kullman Reports about changes of alpine plant species richness over the past 60 years in the Swedish Scandes are reviewed, synthesized and updated with data from recent reinventories. Methodologically, this endeavour is based on resurveys of the floristic composition on the uppermost 20 m of four high-mountain summits. The key finding is that the species pool has increased by 60,170% since the 1950s and later. Some of the invading species are new to the alpine tundra, with more silvine and thermophilic properties than the extant alpine flora. Not a single species of the original flora has disappeared from any of the summits. This circumstance is discussed in perspective of widespread expectations of pending temperature-driven extinction of alpine species in an alleged future warmer climate. These progressive changes coincided with distinct warming (summer and winter) since the late 1980s. During a short cooler period (1974,1994), the species numbers decreased and the upper elevational limits of some ground cover species descended. Thus, discernible responses, concurrent with both warming and cooling intervals, sustain a strong causal link between climate variability and alpine plant species richness. Methodologically, plot-less revisitation studies of the present kind are beset with substantial uncertainties, which may overstate floristic changes over time. However, it is argued here that carefully executed and critically interpreted, no other method can equally effectively sense the earliest phases of plant invasions into alpine vegetation. [source] Monetary Policy, Price Stability and Output Gap StabilizationINTERNATIONAL FINANCE, Issue 2 2002Vitor Gaspar Using a standard New,Keynesian model, this paper examines three reasons why monetary policy should primarily focus on price stability rather than the stabilization of output around potential, even if there appears to be an exploitable trade,off between the volatility of inflation and that of the output gap. First, we discuss the well,known time,inconsistency problem associated with active output gap stabilization. Increasing the relative weight on inflation stabilization improves the equilibrium outcome. Second, we analyse some of the problems associated with the substantial uncertainty that surrounds estimates of potential output. We argue that focusing on price stability is a robust monetary policy strategy in the face of such uncertainty. Finally, we consider the case where private agents are trying to estimate the inflation generating process using an ,ad hoc', but reasonable learning rule. By emphasizing a single goal the central bank facilitates the process of learning, thereby stablizing both inflation and the output gap. [source] Quantifying the uncertainty about the half-life of deviations from PPPJOURNAL OF APPLIED ECONOMETRICS, Issue 2 2002Lutz Kilian We propose a Bayesian framework in which the uncertainty about the half-life of deviations from purchasing power parity can be quantified. Based on the responses to a survey study, we propose a prior probability distribution for the half-life under the recent float intended to capture widely held views among economists. We derive the posterior probability distribution of the half-life under this consensus prior and confirm the presence of substantial uncertainty about the half-life. We provide for the first time a comprehensive formal evaluation of several nonnested hypotheses of economic interest, including Rogoff's (1996) claim that the half-life is contained in the range of 3 to 5 years. We find that no hypothesis receives strong support from the data. Copyright © 2002 John Wiley & Sons, Ltd. [source] At what degree of belief in a research hypothesis is a trial in humans justified?JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2002Benjamin Djulbegovic MD Abstract Rationale, aims and objectives,Randomized controlled trials (RCTs) have emerged as the most reliable method of assessing the effects of health care interventions in clinical medicine. However, RCTs should be undertaken only if there is substantial uncertainty about which of the trial treatments would benefit a patient most. The purpose of this study is to determine the degree of uncertainty in a research hypothesis before it can empirically be tested in an RCT. Methods,We integrated arguments from three independent lines of research , on ethics, principles of the design and conduct of clinical trials, and medical decision making , to develop a decision model to help solve the dilemma of under which circumstances innovative treatments should be tested in an RCT. Results,We showed that RCTs are the preferable option to resolve uncertainties about competing treatment alternatives whenever we desire reliable, undisputed, high-quality evidence with a low likelihood of false-positive or false-negative results. Conclusions When the expected benefit : risk ratio of a new treatment is small, an RCT is justified to resolve uncertainties over a wide range of prior belief (e.g. 10,90%) in the accuracy of the research hypothesis. Randomized controlled trials represent the best means for resolving uncertainties about health care interventions. [source] Natural History of Asymptomatic Intracranial Arterial StenosisJOURNAL OF NEUROIMAGING, Issue S1 2009Robert A. Taylor MD ABSTRACT The prevalence and natural history of asymptomatic intracranial arterial stenosis are not very well characterized. Existing data suggest that incidentally discovered asymptomatic intracranial stenosis presents a fairly low risk of stroke, though substantial uncertainty remains. Patients may be at greater risk if there are tandem stenoses. Methods to stratify the risk of stroke with asymptomatic intracranial atherosclerotic lesions have yet to be established and validated. In general, aggressive intervention for an asymptomatic intracranial stenosis is not currently recommended. [source] HOMEOWNERSHIP IN AN UNCERTAIN WORLD WITH SUBSTANTIAL TRANSACTION COSTS,JOURNAL OF REGIONAL SCIENCE, Issue 5 2007Margaret H. Smith ABSTRACT This paper presents a dynamic model of residential real estate tenure decisions that takes into account the substantial transaction costs and the uncertain time paths of rents and prices. By temporarily postponing decisions, buyers and sellers obtain additional information and may avoid transactions that are costly to reverse. One implication is that the combination of high transaction costs and substantial uncertainty can create a large wedge between a household's reservation prices for buying and selling a home, which can explain why households do not switch back and forth between owning and renting as home prices fluctuate. [source] Burden of disease attributable to selected environmental factors and injury among children and adolescents in EuropeCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 6 2004Richard Reading Burden of disease attributable to selected environmental factors and injury among children and adolescents in Europe . ValentF, LittleD, BertolliniR, NemerLE, BarboneF & TamburliniG . ( 2004 ) Lancet , 363 , 2032 , 2039 . Background Environmental exposures contribute to the global burden of disease. We have estimated the burden of disease attributable to outdoor and indoor air pollution, inadequate water and sanitation, lead exposure, and injury among European children and adolescents. Methods Published studies and reports from international agencies were reviewed for calculation of risk-factor exposure in Europe. Disability-adjusted life years (DALYs) or deaths attributable to each factor, or both, were estimated by application of the potential impact fraction to the estimates of mortality and burden of disease from the WHO global database of burden of disease. Findings Among children aged 0,4 years, between 1.8% and 6.4% of deaths from all causes were attributable to outdoor air pollution; acute lower-respiratory-tract infections attributable to indoor air pollution accounted for 4.6% of all deaths and 3.1% of DALYs; and mild mental retardation resulting from lead exposure accounted for 4.4% of DALYs. In the age-group 0,14 years, diarrhoea attributable to inadequate water and sanitation accounted for 5.3% of deaths and 3.5% of DALYs. In the age-group 0,19 years, injuries were the cause of 22.6% of all deaths and 19.0% of DALYs. The burden of disease was much higher in European subregions B and C than subregion A. There was substantial uncertainty around some of the estimates, especially for outdoor air pollution. Interpretation Large proportions of deaths and DALYs in European children are attributable to outdoor and indoor air pollution, inadequate water and sanitation, lead exposure, and injuries. Interventions aimed at reducing children's exposure to environmental factors and injuries could result in substantial gains. The pronounced differences by subregion and age indicate the need for targeted action. [source] | |||||||||||||||||||