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Low Accuracy (low + accuracy)
Selected AbstractsDifferences in spatial predictions among species distribution modeling methods vary with species traits and environmental predictorsECOGRAPHY, Issue 6 2009Alexandra D. Syphard Prediction maps produced by species distribution models (SDMs) influence decision-making in resource management or designation of land in conservation planning. Many studies have compared the prediction accuracy of different SDM modeling methods, but few have quantified the similarity among prediction maps. There has also been little systematic exploration of how the relative importance of different predictor variables varies among model types and affects map similarity. Our objective was to expand the evaluation of SDM performance for 45 plant species in southern California to better understand how map predictions vary among model types, and to explain what factors may affect spatial correspondence, including the selection and relative importance of different environmental variables. Four types of models were tested. Correlation among maps was highest between generalized linear models (GLMs) and generalized additive models (GAMs) and lowest between classification trees and GAMs or GLMs. Correlation between Random Forests (RFs) and GAMs was the same as between RFs and classification trees. Spatial correspondence among maps was influenced the most by model prediction accuracy (AUC) and species prevalence; map correspondence was highest when accuracy was high and prevalence was intermediate (average prevalence for all species was 0.124). Species functional type and the selection of climate variables also influenced map correspondence. For most (but not all) species, climate variables were more important than terrain or soil in predicting their distributions. Environmental variable selection varied according to modeling method, but the largest differences were between RFs and GLMs or GAMs. Although prediction accuracy was equal for GLMs, GAMs, and RFs, the differences in spatial predictions suggest that it may be important to evaluate the results of more than one model to estimate the range of spatial uncertainty before making planning decisions based on map outputs. This may be particularly important if models have low accuracy or if species prevalence is not intermediate. [source] Influence of moisture content on measurement accuracy of porous media thermal conductivityHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2009Mingzhi Yu Abstract The thermal conductivity measurement accuracy of sand was experimentally studied with a hot disk thermal constant analyzer and water morphologies, distribution, and evolution at the pore scale were observed with a charge coupled device (CCD) combined with a microscope. It was found that thermal conductivities of samples with low moisture content (<25%) could not be accurately measured. For samples with low moisture content, the analysis showed that the water in the region adjacent to the analyzer sensor mainly existed as isolated liquid bridges between/among sand particles and would evaporate and diffuse to relatively far regions because of being heated by the sensor during measurement. Water evaporation and diffusion caused the sample constitution in the region adjacent to the sensor to vary throughout the whole measurement process, and accordingly induced low accuracy of the obtained thermal conductivities. Due to high water connectivity in pores, the rate of water evaporation and diffusion in porous media of high moisture content was relatively slow when compared with that of low moisture content. Meanwhile, water in the relatively far regions flowed back to the region adjacent to the sensor by capillary force. Therefore, samples consisting of the region adjacent to the sensor maintained the constant and thermal conductivities of porous media with relatively high moisture content and could be measured with high accuracy. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20272 [source] The rapid spread of invasive Eurasian Collared Doves Streptopelia decaocto in the continental USA follows human-altered habitatsIBIS, Issue 3 2010IKUKO FUJISAKI Understanding factors related to the range expansion trajectory of a successful invasive species may provide insights into environmental variables that favour additional expansion or guide monitoring and survey efforts for this and other invasive species. We examined the relationship of presence and abundance of Eurasian Collared Doves Streptopelia decaocto to environmental factors using recent data from the North American Breeding Bird Survey to understand factors influencing its expansion into the continental USA. A zero-inflated Poisson (ZIP) model was used to account for excess zero observations because this species was not observed on the majority of survey routes, despite its large geographical range. Model fit was improved when we included environmental covariates as compared with the null model, which only included distance from the route where this species was first observed. Probability of zero count was positively related to the distance from the first route and road density and was inversely related to minimum temperature and distance to coast. Abundance of the species was positively related to road density and was inversely related to annual precipitation and distance to coast. Random intercept by land-cover type also improved model fit. Model fit was improved with the ZIP model over the standard Poisson model, suggesting that presence and abundance of this species are characterized by different environmental factors. However, overall low accuracy of model-predicted presence/absence and abundance with the independent validation dataset may indicate either that there are other explanatory factors or that there is great uncertainty in the species' colonization process. Our large-scale study provides additional evidence that the range expansion of this species tends to follow human-altered landscapes such as road and agricultural areas as well as responding to general geographical features such as coastlines or thermal clines. Such patterns may hold true for other invasive species and may provide guidelines for monitoring and assessment activities in other invasive taxa. [source] Classifying degenerative joint disease by the RDC/TMD and by panoramic imaging: a retrospective analysisJOURNAL OF ORAL REHABILITATION, Issue 3 2010E. WINOCUR Summary, The purposes of the study were to evaluate the utility of diagnosing degenerative joint disease (DJD) by the clinical finding of coarse crepitus alone, without supporting imaging studies, as defined by the RDC/TMD, and to evaluate the contribution of panoramic radiography as an aid in the diagnosis of DJD. A retrospective analysis of 372 consecutive patients with TMD was conducted. Their panoramic radiographs were evaluated for the extent of their contribution to the final diagnosis. Panoramic radiography was of no diagnostic value in 94·4% of the cases when the group was considered as a whole. When patients diagnosed with DJD were considered separately, panoramic radiography was completely sufficient for reaching the final diagnosis in 20·0% of the cases. In almost 90% of these patients, however, the clinical examination did not support the diagnosis of DJD (no coarse crepitus was found). This raises some doubts about the effectiveness of the clinical examination according to the RDC/TMD and about the utility of panoramic radiography in the definitive diagnosis of DJD, because both techniques have low accuracy (11·1% and 20%, respectively). The present study supports the current recommendations that panoramic radiography should not be ordered routinely to assess DJD, but still it is first choice when any dental problem is suspected. Further additional imaging (computerized tomography, magnetic resonance imaging) should be considered only if there is reason to expect that the findings might affect diagnosis and management. This study adds to recent criticisms of the clinical validity of the RDC/TMD, with regard to DJD. [source] Children's prepared and unprepared lies: can adults see through their strategies?APPLIED COGNITIVE PSYCHOLOGY, Issue 4 2007Leif A. Strömwall We investigated adults' ability to detect children's prepared and unprepared lies and truths. Furthermore, we examined children's strategies when lying. Thirty children (11,13 years) were interviewed about one self-experienced and one invented event each. Half had prepared their statements, the other half not. Sixty adult observers assessed the veracity of 10 videotaped statements each. Overall deception detection accuracy (51.5%) was not better than chance. The adults showed higher accuracy for unprepared statements (56.6%), than prepared statements (46.1%). The adults reported to have used more verbal than nonverbal cues to deception, especially the Detail criterion. The most frequent verbal strategy reported by the children was to use real-life components (e.g. own or others' experiences); the most frequent nonverbal strategy was to stay calm. Arguably, the low accuracy is due to adults' failure to see through the lying children's strategies. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||