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Support Predictions (support + prediction)
Selected AbstractsAdverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessmentENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010Gerald T. Ankley Abstract Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk,effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework. Environ. Toxicol. Chem. 2010;29:730,741. © 2009 SETAC [source] An intelligent logistics support system for enhancing the airfreight forwarding businessEXPERT SYSTEMS, Issue 5 2004H.C.W. Lau Abstract: Recent research related to the aircraft container loading and scheduling problem for airfreight forwarding business has seen significant advances in terms of load plan optimization, taking into account the cost and volume of packed boxes. In today's competitive industrial environment, it is essential that freight forwarders are able to collaborate with carriers (airline companies) to achieve the best possible selection of logistics workflow. However, study of contemporary research publications indicates that there is a dearth of articles related to the design and implementation of an intelligent logistics system to support decision-making on carrier selection, aircraft container loading plans as well as carrier benchmarking. This paper presents an intelligent logistics support system (ILSS) which is able to provide expert advice related to the airfreight forwarding business, enhancing the logistics operations in relevant activities within the value chain of tasks. ILSS comprises a heuristics-based intelligent expert system which supports carrier searching and cargo trading planning as well as load plan generation. The proposed approach is meant to enhance various operations in the airfreight forwarding business, adopting computational intelligence technologies such as rule-based reasoning to provide domain advice and heuristics to support the generation of load plans. After potential outcomes are generated by the heuristics-based intelligent expert system, a neural network engine is applied to support prediction of unexpected events. To validate the viability of this approach, a production system using the ILSS has been developed and subsequently applied in an emulated airfreight forwarding environment. The application results indicate that the operation time from searching for potential carriers to the execution of the order is greatly reduced. In this paper, details related to the structure, design and implementation of the ILSS are also covered with the inclusion of the actual program codes for building the prototype. [source] Bergmann's rule and the mammal fauna of northern North AmericaECOGRAPHY, Issue 6 2004Tim M. Blackburn The observation that "on the whole,,larger species live farther north and the smaller ones farther south" was first published by Carl Bergmann in 1847. However, why animal body mass might show such spatial variation, and indeed whether it is a general feature of animal assemblages, is currently unclear. We discuss reasons for this uncertainty, and use our conclusions to direct an analysis of Bergmann's rule in the mammals in northern North America, in the communities of species occupying areas that were covered by ice at the last glacial maximum. First, we test for the existence of Bergmann's rule in this assemblage, and investigate whether small- and large-bodied species show different spatial patterns of body size variation. We then attempt to explain the spatial variation in terms of environmental variation, and evaluate the adequacy of our analyses to account for the spatial pattern using the residuals arising from our environmental models. Finally, we use the results of these models to test predictions of different hypotheses proposed to account for Bergmann's rule. Bergmann's rule is strongly supported. Both small- and large-bodied species exhibit the rule. Our environmental models account for most of the spatial variation in mean, minimum and maximum body mass in this assemblage. Our results falsify predictions of hypotheses relating to migration ability and random colonisation and diversification, but support predictions of hypotheses relating to both heat conservation and starvation resistance. [source] Habitat heterogeneity affects population growth in goshawk Accipiter gentilisJOURNAL OF ANIMAL ECOLOGY, Issue 2 2001Oliver Krüger Summary 1The concept of site-dependent population regulation combines the ideas of Ideal Free Distribution-type of habitat settlement and density dependence in a vital rate mediated by habitat heterogeneity. The latter is also known as habitat heterogeneity hypothesis. Site-dependent population regulation hypothesis predicts that increasing population density should lead to inhabitation of increasingly poor territories and decreasing per capita population growth rate. An alternative mechanism for population regulation in a territorial breeding system is interference competition. However, this would be expected to cause a more even decrease in individual success with increasing density than site-dependent regulation. 2We tested these ideas using long-term (1975,99) population data from a goshawk Accipiter gentilis population in Eastern Westphalia, Germany. 3Goshawk territory occupancy patterns and reproduction parameters support predictions of site-dependent population regulation: territories that were occupied more often and earlier had a higher mean brood size. Fecundity did not decrease with increasing density in best territories. 4Using time-series modelling, we also showed that the most parsimonious model explaining per capita population growth rate included annual mean habitat quality, weather during the chick rearing and autumn period and density as variables. This model explained 63% of the variation in per capita growth rate. The need for including habitat quality in the time-series model provides further support for the idea of site-dependent population regulation in goshawk. [source] Organizational Politics, Perceived Control, and Work Outcomes: Boundary Conditions on the Effects of Politics,JOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 3 2001Dennis P. Bozeman This investigation examined the moderating influences of perceived control (i. e., personal control and job self-efficacy) on relationships between perceptions of organizational politics and organizational commitment, job satisfaction, intention to turnover, and job stress. Although results failed to support predictions concerning the interaction of perceptions of organizational politics and personal control, some support was found for predictions concerning the interactive influence of perceptions of organizational politics and job self-efficacy on outcomes. Data from 189 hotel managers supported the hypothesized interactive effects of perceptions of organizational politics and job self-efficacy for the outcomes of organizational commitment and job satisfaction. These results suggest that job self-efficacy exacerbates the relationship between perceived politics and certain dysfunctional attitudes. [source] The limitations of randomized controlled trials in predicting effectivenessJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2010Nancy Cartwright PhD FBA Abstract What kinds of evidence reliably support predictions of effectiveness for health and social care interventions? There is increasing reliance, not only for health care policy and practice but also for more general social and economic policy deliberation, on evidence that comes from studies whose basic logic is that of JS Mill's method of difference. These include randomized controlled trials, case,control studies, cohort studies, and some uses of causal Bayes nets and counterfactual-licensing models like ones commonly developed in econometrics. The topic of this paper is the ,external validity' of causal conclusions from these kinds of studies. We shall argue two claims. Claim, negative: external validity is the wrong idea; claim, positive: ,capacities' are almost always the right idea, if there is a right idea to be had. If we are right about these claims, it makes big problems for policy decisions. Many advice guides for grading policy predictions give top grades to a proposed policy if it has two good Mill's-method-of difference studies that support it. But if capacities are to serve as the conduit for support from a method-of-difference study to an effectiveness prediction, much more evidence, and much different in kind, is required. We will illustrate the complexities involved with the case of multisystemic therapy, an internationally adopted intervention to try to diminish antisocial behaviour in young people. [source] Fine-scale natal homing and localized movement as shaped by sex and spawning habitat in Chinook salmon: insights from spatial autocorrelation analysis of individual genotypesMOLECULAR ECOLOGY, Issue 14 2006H. M. NEVILLE Abstract Natal homing is a hallmark of the life history of salmonid fishes, but the spatial scale of homing within local, naturally reproducing salmon populations is still poorly understood. Accurate homing (paired with restricted movement) should lead to the existence of fine-scale genetic structuring due to the spatial clustering of related individuals on spawning grounds. Thus, we explored the spatial resolution of natal homing using genetic associations among individual Chinook salmon (Oncorhynchus tshawytscha) in an interconnected stream network. We also investigated the relationship between genetic patterns and two factors hypothesized to influence natal homing and localized movements at finer scales in this species, localized patterns in the distribution of spawning gravels and sex. Spatial autocorrelation analyses showed that spawning locations in both sub-basins of our study site were spatially clumped, but the upper sub-basin generally had a larger spatial extent and continuity of redd locations than the lower sub-basin, where the distribution of redds and associated habitat conditions were more patchy. Male genotypes were not autocorrelated at any spatial scale in either sub-basin. Female genotypes showed significant spatial autocorrelation and genetic patterns for females varied in the direction predicted between the two sub-basins, with much stronger autocorrelation in the sub-basin with less continuity in spawning gravels. The patterns observed here support predictions about differential constraints and breeding tactics between the two sexes and the potential for fine-scale habitat structure to influence the precision of natal homing and localized movements of individual Chinook salmon on their breeding grounds. [source] Plant ontogeny and chemical defence: older seedlings are better defendedOIKOS, Issue 5 2009Arnaud Elger Although patterns of seedling selection by herbivores are strongly influenced by plant age and the expression of anti-herbivore defence, it is unclear how these characteristics interact to influence seedling susceptibility to herbivory. We tracked ontogenetic changes in a range of secondary metabolites (total phenolics, alkaloids and cyanogenic glycosides) commonly associated with seedling defence for nine sympatric British grassland species. Although there was marked variation in concentrations of secondary metabolites between different species, we found a consistent increase in the deployment of phenolics, alkaloids and cyanogenics with seedling age for six of the seven dicotyledonous species examined. The two grass species by contrast exhibited low levels of secondary metabolites across all developmental stages, possibly due to an investment in structural (silica phytoliths) defence. Our results corroborate species-specific patterns of seedling herbivory observed in field studies, and offer some explanation for the relatively high sensitivity to herbivore attack frequently observed for relatively young seedlings compared with their older conspecifics. Our results also support predictions made by the growth,differentiation balance hypothesis regarding ontogenetic changes in resource allocation to anti-herbivore defence for a range of potential chemical defences and across a range of sympatric plant species presumably subject to broadly similar selective pressures at the regeneration stage. [source] | ||||||||||