Abstract: Predictive models can help clarify the distribution of poorly known species but should display strong transferability when applied to independent data. Nevertheless, model transferability for threatened tropical species is poorly studied. We built models predicting the incidence of the critically endangered Bengal Florican ( Houbaropsis bengalensis ) within the Tonle Sap (TLS) floodplain, Cambodia. Separate models were constructed with soil, land-use, and landscape data and species incidence sampled over the entire floodplain (12,000 km2) and from the Kompong Thom (KT) province (4000 km2). In each case, the probability of Bengal Florican presence within randomly selected 1 × 1 km squares was modeled by binary logistic regression with multimodel inference. We assessed the transferability of the KT model by comparing predictions with observed incidence elsewhere in the floodplain. In terms of standard model-validation statistics, the KT model showed good spatial transferability. Nevertheless, it overpredicted florican presence outside the KT calibration region, classifying 491 km2 as suitable habitat compared with 237 km2 predicted as suitable by the TLS model. This resulted from higher species incidence within the calibration region, probably owing to a program of conservation education and enforcement that has reduced persecution there. Because both research and conservation activity frequently focus on areas with higher density, such effects could be widespread, reducing transferability of predictive distribution models. 相似文献
Objective: Teenage drivers are more likely to be involved in severely incapacitating and fatal crashes compared to adult drivers. Moreover, because two thirds of urban vehicle miles traveled are on signal-controlled roadways, significant research efforts are needed to investigate intersection-related teenage driver injury severities and their contributing factors in terms of driver behavior, vehicle–infrastructure interactions, environmental characteristics, roadway geometric features, and traffic compositions. Therefore, this study aims to explore the characteristic differences between teenage and adult drivers in intersection-related crashes, identify the significant contributing attributes, and analyze their impacts on driver injury severities.
Methods: Using crash data collected in New Mexico from 2010 to 2011, 2 multinomial logit regression models were developed to analyze injury severities for teenage and adult drivers, respectively. Elasticity analyses and transferability tests were conducted to better understand the quantitative impacts of these factors and the teenage driver injury severity model's generality.
Results: The results showed that although many of the same contributing factors were found to be significant in the both teenage and adult driver models, certain different attributes must be distinguished to specifically develop effective safety solutions for the 2 driver groups.
Conclusions: The research findings are helpful to better understand teenage crash uniqueness and develop cost-effective solutions to reduce intersection-related teenage injury severities and facilitate driver injury mitigation research. 相似文献
Background, Goals and Scope In response to concerns that have been raised about chemical substances that may alter the function of endocrine systems and
result in adverse effects on human health, an OECD initiative was undertaken to develop and validate in vitro and in vivo assays to identify chemicals that may interfere with endocrine systems of vertebrates. Here we report on studies that were
conducted to develop and standardize a cell-based screening assay using the H295R cell line to prioritize chemicals that may
act on steroidogenic processes in humans and wildlife. These studies are currently ongoing as part of the ‘Special Activity
on the Testing and Assessment of Endocrine Disruptors’ within the OECD Test Guidelines Program to review, develop, standardize,
and validate a number of in vitro and in vivo toxicological assays for testing and assessment of chemicals concerning their potential to interact with the endocrine system
of vertebrates.
Study Design Six laboratories from five countries participated in the pre-validation studies. Each laboratory tested the effects of three
model chemicals on the production of testosterone (T) and estradiol (E2) using the H295R Steroidogenesis Assay. Chemicals
tested were well described inducers or inhibitors of steroidogenic pathways (forskolin, prochloraz and fadrozole). All experiments
were conducted in 24 well plates following standard protocols. Six different doses per compound were analyzed in triplicate
per plate. A quality control (QC) plate was run in conjunction with the chemical exposure plate to account for inter-assay
variation. Each chemical exposure was conducted two or three times.
Results All laboratories successfully detected increases and/or decreases in hormone production by H295R cells after exposure to the
different model compounds and there was good agreement in the pattern of response for all groups. Forskolin increased both
T and E2 while fadrozole and prochloraz decreased production of both hormones. All chemicals affected hormone production in
a dose-dependent manner with the exception of fadrozole which caused maximum inhibition of E2 at the two least concentrations
tested. Some inter-laboratory differences were noted in the alteration of hormone production measured in chemically exposed
cells. However, with the exception of the production of T measured at one laboratory in cells exposed to forskolin, the EC50s calculated were comparable (coefficients of variation 34–49%) for all hormones.
Discussion and Perspectives The results indicated that the H295R Steroidogenesis Assay protocol was robust, transferable and reproducible among all laboratories.
However, in several instances that were primarily related to one laboratory there were unexplained minor uncertainties related
to the inter-laboratory hormone production variation. Based on the findings from this Phase 2 prevalidation study, the H295R
Steroidogenesis Assay protocol is currently being refined. The next phase of the OECD validation program will test the refined
protocol among the same group of laboratories using an extended set of chemicals (∼30) that will include positive and negative
chemical controls as well as a broad spectrum of different potential inducers and inhibitors of steroidogenic pathways.
Submission Editor: Dr. Carsten Brühl (bruehl@uni-landau.de) 相似文献
The rare deposition of water resources conflicts with its limitless demand. This determined the existence of the water rights transaction system. The implementation of the water rights transaction system requires clarifying the definition of water resource right above all distinctly. At present, it is a kind of common right system arrangement which needs the Chinese government to dispose of water resources. Though a series of management systems guaranteed the government's supply of water resource, it hindered the development of the water market seriously and caused the utilization of water resources to stay in the inefficient or low efficient state for a long time. Thus, we should change the government's leading role in the resource distribution and really rely on the market to carry on the water rights trade and transaction. In this way, the water rights could become a kind of private property right relatively, and circulate freely in the market. As a result of this, we should overcome the defects of common right, make its external performance internalized maximally and achieve the optimized water resource disposition and use it more effectively. 相似文献
Abstract The rare deposition of water resources conflicts with its limitless demand. This determined the existence of the water rights transaction system. The implementation of the water rights transaction system requires clarifying the definition of water resource right above all distinctly. At present, it is a kind of common right system arrangement which needs the Chinese government to dispose of water resources. Though a series of management systems guaranteed the government’s supply of water resource, it hindered the development of the water market seriously and caused the utilization of water resources to stay in the inefficient or low efficient state for a long time. Thus, we should change the government’s leading role in the resource distribution and really rely on the market to carry on the water rights trade and transaction. In this way, the water rights could become a kind of private property right relatively, and circulate freely in the market. As a result of this, we should overcome the defects of common right, make its external performance internalized maximally and achieve the optimized water resource disposition and use it more effectively. 相似文献