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Inherent Uncertainties (inherent + uncertainty)
Selected AbstractsThe role of floristic survey data and quantitative analysis in identification and description of ecological communities under threatened species legislation: A case study from north-eastern New South WalesECOLOGICAL MANAGEMENT & RESTORATION, Issue 2009Penny Kendall Summary The concept of ecological communities play an important role in conservation planning and natural resource management. However, inherent uncertainties in the definition and identification of individual communities make it difficult to assess whether particular communities are present on particular sites and how they may be affected by proposed developments or management actions. If communities are poorly defined or misidentified, they may not perform their intended role as effective representations of biodiversity. We use a case study of forest communities dominated by Brown Barrel (Eucalyptus fastigata) in north-eastern New South Wales to demonstrate the value of quantitative floristic survey data for resolving robust and effective classifications of communities. Numerical analyses of an extensive set of floristic data suggested a re-configuration of a prior classification based largely on subjective interpretation. Although the general existence of assemblages dominated by Brown Barrel was confirmed, the new classification replaced three prior units with two assemblages that were more robust and better reflected the overall patterns in species composition. As only one of the two assemblages potentially warranted threatened status, the new classification allows scarce conservation resources to be targeted where they are most needed. The quantitative survey data also enabled a more detailed floristic description of the assemblages and provided a basis for maps of point locations and modelled habitat. These maps identified previously undocumented occurrences of the communities and helped to assess their extent of decline since European settlement. Improving the coverage of quadrat-based floristic sampling is therefore a valuable and cost-effective investment to inform better management of native vegetation and biodiversity. [source] Preclinical evaluation of tolerance induction protocols and islet transplantation in non-human primatesIMMUNOLOGICAL REVIEWS, Issue 1 2001Sean P. Montgomery Summary: Non-human primate studies of tolerance induction strategies in solid organ transplantation represent a critical bridge between studies in rodents and humans. Our work demonstrates that strategies involving the blockade of co-stimulatory molecules, especially the CD40,CD154 pathway, have great potential for clinical adaptation. While the combination of anti-CD154 antibody with blockade of the CD28 pathway reduced donor antibody production, graft survival was not significantly improved over that achieved with anti-CD154 antibody alone. Moreover, although long courses of steroids seem to interfere with this approach, it may be possible to combine blockade of the CD40,CD154 pathway with other conventional immunosuppressants without sacrificing efficacy. This is a key issue for reducing the risk associated with eventual clinical trials. Work in the non-human primate islet transplant model demonstrates that viable islets can be recovered, isolated and infused in a reliable fashion. It also confirms the efficacy of a steroid sparing approach to immunosuppression for islet transplantation. These data have been expanded to the kidney allograft model, setting the stage for kidney islet transplantation studies. Overall, tolerance induction and islet transplant studies in non-human primates permit the preclinical screening of promising immunomodulatory approaches developed in rodents and reduce the inherent uncertainties associated with adapting new regimens to the clinic. [source] A Streamflow Forecasting Framework using Multiple Climate and Hydrological Models,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2009Paul J. Block Abstract:, Water resources planning and management efficacy is subject to capturing inherent uncertainties stemming from climatic and hydrological inputs and models. Streamflow forecasts, critical in reservoir operation and water allocation decision making, fundamentally contain uncertainties arising from assumed initial conditions, model structure, and modeled processes. Accounting for these propagating uncertainties remains a formidable challenge. Recent enhancements in climate forecasting skill and hydrological modeling serve as an impetus for further pursuing models and model combinations capable of delivering improved streamflow forecasts. However, little consideration has been given to methodologies that include coupling both multiple climate and multiple hydrological models, increasing the pool of streamflow forecast ensemble members and accounting for cumulative sources of uncertainty. The framework presented here proposes integration and offline coupling of global climate models (GCMs), multiple regional climate models, and numerous water balance models to improve streamflow forecasting through generation of ensemble forecasts. For demonstration purposes, the framework is imposed on the Jaguaribe basin in northeastern Brazil for a hindcast of 1974-1996 monthly streamflow. The ECHAM 4.5 and the NCEP/MRF9 GCMs and regional models, including dynamical and statistical models, are integrated with the ABCD and Soil Moisture Accounting Procedure water balance models. Precipitation hindcasts from the GCMs are downscaled via the regional models and fed into the water balance models, producing streamflow hindcasts. Multi-model ensemble combination techniques include pooling, linear regression weighting, and a kernel density estimator to evaluate streamflow hindcasts; the latter technique exhibits superior skill compared with any single coupled model ensemble hindcast. [source] Sonography and Sociality: Obstetrical Ultrasound Imaging in Urban VietnamMEDICAL ANTHROPOLOGY QUARTERLY, Issue 2 2007Tine Gammeltoft This article is about new reproductive technologies, maternal anxieties, and existential uncertainties. It explores the question of why pregnant women in Vietnam's capital, Hanoi, have become avid consumers of obstetrical ultrasound scanning even while expressing profound doubts regarding the reliability and safety of this new technology of pregnancy. Through a phenomenological analysis of the social production of women's sense of reproductive risks and uncertainties, the article shows how Hanoian women's paradoxical stances toward ultrasound imaging can be explained through a consideration of embodied and historically generated experiences within everyday local worlds. The article argues that the "scientific stories" of fetal well-being and normality that are produced through ultrasonography are challenged by vivid and continual exchanges in everyday lives of stories of the inherent uncertainties of existence in general and of human reproduction in particular. [source] Covariate Adjusted Correlation Analysis with Application to,FMR1,Premutation Female Carrier DataBIOMETRICS, Issue 3 2009Damla, entürk Summary Motivated by molecular data on female premutation carriers of the fragile X mental retardation 1 (FMR1) gene, we present a new method of covariate adjusted correlation analysis to examine the association of messenger RNA (mRNA) and number of CGG repeat expansion in the,FMR1,gene. The association between the molecular variables in female carriers needs to adjust for activation ratio (ActRatio), a measure which accounts for the protective effects of one normal X chromosome in females carriers. However, there are inherent uncertainties in the exact effects of ActRatio on the molecular measures of interest. To account for these uncertainties, we develop a flexible adjustment that accommodates both additive and multiplicative effects of ActRatio nonparametrically. The proposed adjusted correlation uses local conditional correlations, which are local method of moments estimators, to estimate the Pearson correlation between two variables adjusted for a third observable covariate. The local method of moments estimators are averaged to arrive at the final covariate adjusted correlation estimator, which is shown to be consistent. We also develop a test to check the nonparametric joint additive and multiplicative adjustment form. Simulation studies illustrate the efficacy of the proposed method. (Application to,FMR1,premutation data on 165 female carriers indicates that the association between mRNA and CGG repeat after adjusting for ActRatio is stronger.) Finally, the results provide independent support for a specific jointly additive and multiplicative adjustment form for ActRatio previously proposed in the literature. [source] Higher education, policy schools, and development studies: what should masters degree students be taught?,JOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 1 2007Michael Woolcock Abstract What are the distinctive skills and attributes that should be expected of Masters (as opposed to undergraduate and doctoral) graduates of international development programmes? Given the diversity of their academic and cultural backgrounds, the inherent uncertainty of their career trajectories, the variety of country contexts and organizational environments in which they will be working, and the range of constituent groups with which they are likely to interact on a regular basis, I argue that Masters degree programmes in development studies should focus on helping students acquire three core competencies,the skills of ,detectives' (data collection, analysis and interpretation), ,translators' (reframing given ideas for diverse groups), and ,diplomats' (negotiation, conflict mediation, deal making). Copyright © 2006 John Wiley & Sons, Ltd. [source] Skeletal age, dental age, and the maturation of KNM-WT 15000AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2004Shelley L. Smith Abstract The skeleton of the Homo erectus boy from West Lake Turkana, Kenya (KNM-WT 15000), is remarkably complete, and this individual has thus provided a case study for several researchers examining Homo erectus growth. Using data from a longitudinal study of Montreal French-Canadian children, it is shown that while dental and skeletal ages match reasonably well at the level of a sample of children, individuals can display differences between skeletal and dental ages of 2 years or more. Furthermore, the relationship between these two markers may change over time in individual children. It is also possible to find children with patterns of dental maturation similar to KNM-WT 15000's pattern in the Montreal sample. Therefore, neither the discrepancy between skeletal age and dental age alone nor the pattern of dental maturation as assessed by dental stages precludes a human-like pattern of growth, including an adolescent growth spurt, for this individual. Some indicators (e.g., estimated body size for predicted age, and enamel formation) do suggest possible growth-patterning differences from modern humans, and therefore earlier maturation is a reasonable hypothesis, but caution is warranted, given the large degree of modern human variation in developmental markers and the inherent uncertainty in precise estimation of KNM-WT 15000's maturational parameters. Am J Phys Anthropol, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||