Generalized extreme value regression for ordinal response data

This paper introduces a flexible skewed link function for modeling ordinal response data with covariates based on the generalized extreme value (GEV) distribution. Commonly used probit, logit and complementary log-log links are prone to link misspecification because of their fixed skewness. The GEV link is flexible in fitting the skewness in the response curve with a free shape parameter. Using Bayesian methodology, it automatically detects the skewness in the response curve along with the model fitting. The flexibility of the proposed model is illustrated by its application to an ecological survey data about the coverage of Berberis thunbergii in New England. We employ the latent variable approach by Albert and Chib (J Am Stat Assoc 88:669–679, (1993) to develop computational schemes. For model selection, we employ the Deviance Information Criterion (DIC).     

An integrated model of regional and local residential sorting with application to air quality

We examine the interconnectedness of demand for regionally and locally varying public goods using a residential sorting model. We propose a version of the model that describes household choices at the city (MSA) level and, conditional on city, the neighborhood (census tract) level. We use a two-stage budgeting argument to develop an empirically feasible sorting model that allows us to estimate preferences for regionally varying air quality while accounting for sorting at the local level. Our conceptual and empirical approach nests previous sorting models as special cases, allowing us to assess the importance of accounting for multiple spatial scales in our predictions for the cost of air pollution. Furthermore our preferred specification connects the city and neighborhood sorting margins to the upper and lower elements of a nested logit model, thereby establishing a useful correspondence between two stage budgeting and nested logit estimation. Empirically we find that estimates from a conventional model of sorting across MSAs imply a smaller marginal willingness to pay for air quality than estimates from our proposed model. We discuss how the difference is attributable in part to the omitted variable problems arising when tract level sorting is ignored.     

Estimating the benefits of recreation under conditions of congestion: Comments and extension

The purpose of this paper is to comment on and extend the analysis of a paper by Wetzel. He uses a commonly accepted model of demand for a congested recreational resource and shows how the Clawson method of estimating a recreational demand curve relates to it. Much of his analysis is useful but he errs in his interpretation of the proper value of consumer surplus. In this paper a specific formalization of the demand model is developed for the first time and it is used to show the correct measure of consumer surplus and how to specify the proper level of use for the congested resource.     

A robust weighted EM algorithm for use-availability data

Wildlife sampling for habitat selection often combines a random background sample with a random sample of used sites, because the background sample could contain too few used sites to be informative for rare species. This approach is referred to as use-availability sampling. Two variants are considered where there is: (1) a random background sample including used and unused sites augmented with a sample of used sites, and (2) a sample of used sites augmented with a contaminated background sample, i.e. use is not recorded. A weighted estimator first proposed by Manski and Lerman (Econometrica 45(8):1977?C1988, 1977) forms the basis for our suggested approach. The weighted estimator has been shown to perform better than the usual unweighted approach with uncontaminated data and mis-specified logit models (Xie and Manski in Sociol Methods Res 17(3):283?C302, 1989). A weighted EM algorithm is developed for use with contaminated background data. We show that the weighted estimator continues to perform well with contaminated data and maintains its robustness to model mis-specification. The weighted estimator has not been previously used for use-availability sampling due to reliance on the assumption that only the intercept is biased, which is valid for a correct logit model. We show that adjusting the intercept may not eliminate the bias with an incorrect logit model. In this case, the weighted estimator is a relatively simple and effective alternative.     

Simultaneous estimation of jointly dependent recreation participation function

The purpose of this paper is to develop and estimate a simultaneous model of recreation participation. The logic of the model is that participation in one activity (for example, boating) is influenced by and influences participation in other activities (for example, fishing). For the empirical part of our paper we have used the simultaneous logit model developed by P. Schmidt and R. P. Strauss (Econometrics43, 745–755, 1975). For the application, we have applied the simultaneous logit model to participation in summer recreational activities in Rhode Island. Our results show that simultaneous equation models tend to forecast better, but that the specification bias from excluding the endogenous variables tends to be small.     

Air pollution: Household soiling and consumer welfare losses

This paper uses demand and supply functions for cleanliness to estimate household benefits from reduced particulate matter soiling. A demand curve for household cleanliness is estimated, based upon the assumption that households prefer more cleanliness to less. Empirical coefficients, related to particulate pollution levels, for shifting the cleanliness supply curve, are taken from available studies. Consumer welfare gains, aggregated across 123 SMSAs, from achieving the Federal primary particulate standard, are estimated to range from $0.9 to $3.2 million per year (1971 dollars).     

Skew and attribute non-attendance within the Bayesian mixed logit model

We investigate non-attendance to choice set attributes and the accommodation of preference heterogeneity within the mixed logit model. We propose a generalisation of the mixed logit enabling the degree of skew of marginal utility distributions to be estimated. The implementation is Bayesian with the marginal likelihood used as an arbiter of model performance. We find strong evidence of skew in the distributions of marginal utilities for most attributes. Models incorporating skew are preferred in all cases. The irrelevance of an attribute to significant numbers of respondents is a possible cause of such skew. We test alternative empirical accommodations of self-reported attribute non-attendance (ANA) and continue to find strong evidence of skew in the distributions of marginal utilities even having accounted for ANA. We find that, contrary to some recent findings, respondents who report having ignored an attribute typically do indeed have a zero marginal utility for that attribute.     

Valuing congested recreation sites

This note discusses the issue of measuring consumers' surplus at crowded facilities. It is argued that surplus should be measured with congestion held constant. The area under an aggregate demand curve which has congestion varying has no normative significance. Whether travel cost demand curves estimated for congested facilities properly measured consumers' surplus depends on the sampling procedure and the specification of the demand curves.     

浅丘河道生态需水量计算方法对比研究——以鄂北地区水河为例

适宜的生态需水量是保障河道生态系统健康的重要因素,合理地计算生态需水量对河道生态系统评估具有现实意义。以鄂北地区典型浅丘河道——水河为例,基于Qp法(不同频率最枯月平均值法)、频率曲线法、最小月平均流量法、Tennant法及生物习性法5种方法的生态流量计算结果,探讨了各方法计算结果的合理性与适用性。结果表明:由于上下游河道水文条件差异性,上游断面采用生物习性法能较好地拟合河道水文节律变化和水质波动;同理,下游断面采用频率曲线法更加匹配下游河道水文、水质情况。因此,在河道上、下游断面分别采用生物习性法、频率曲线法计算得到适宜生态需水量为0.21 m^3/s、2.02 m^3/s。     

Testing the feasibility of a hypothetical whaling‐conservation permit market in Norway

A cap‐and‐trade system for managing whale harvests represents a potentially useful approach to resolve the current gridlock in international whale management. The establishment of whale permit markets, open to both whalers and conservationists, could reveal the strength of conservation demand, about which little is known. This lack of knowledge makes it difficult to predict the outcome of a hypothetical whale permit market. We developed a bioeconomic model to evaluate the influence of economic uncertainty about demand for whale conservation or harvest. We used simulations over a wide range of parameterizations of whaling and conservation demands to examine the potential ecological consequences of the establishment of a whale permit market in Norwegian waters under bounded (but substantial) economic uncertainty. Uncertainty variables were slope of whaling and conservation demand, participation level of conservationists and their willingness to pay for whale conservation, and functional forms of demand, including linear, quadratic, and log‐linear forms. A whale‐conservation market had the potential to yield a wide range of conservation and harvest outcomes, the most likely outcomes were those in which conservationists bought all whale permits.     

Estimating the benefits of recreation under conditions of congestion congestion

In a recent issue of J. Environ. Econ. Manag. Wetzel showed that the standard travel cost technique will understate recreation benefits under congested conditions because changes in entry fee lead to lowered congestion levels. This comment indicates that benefit projections derived from the travel cost procedure may theoretically overstate the true value of recreation if rising income levels shift the demand curve upwards but fail to account for the contrary effect of increased congestion. The magnitude and direction of the bias that results from omission of a congestion variable is, however, indeterminate when standard econometric techniques are used to develop benefit projections.     

Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

This study presents a phenomenological model that can be used by the water professionals to quantify chlorine decay and disinfection byproduct (DBP) formation in water. The kinetic model was developed by introducing the concept of limiting chlorine demand and extending an established reactive species approach. The limiting chlorine demand, which quantifies chlorine reactive natural organic matter (NOM) on an equivalent basis, was mathematically defined by the relation between ultimate chlorine residue and initial chlorine dose. It was found experimentally that NOM in water has limiting chlorine demand that increases with chlorine dose once the ultimate residue is established. These results indicated that the complex NOM has a unique ability to adjust chemically to the change in redox condition caused by the free chlorine. It is attributed mainly to the redundant functional groups that persist in heterogeneous NOM molecules. The results also demonstrated that the effect of chlorine dose on the rate of chlorine decay can be quantitatively interpreted with the limiting chlorine demand. The kinetic model developed was validated for chlorine decay and chloroacetic acid formation in finished drinking water.     

Substitution between biofuels and fossil fuels: Is there a green paradox?

We show that (i) subsidies for renewable energy policies with the intention of encouraging substitution away from fossil fuels may accentuate climate change damages by hastening fossil fuel extraction, and that (ii) the opposite result holds under some specified conditions. We focus on the case of subsidies for renewable resources produced under increasing marginal costs, and assume that both the renewable resources and the fossil fuels are currently in use. Such subsidies have a direct effect and an indirect effect working in opposite directions. The direct effect is the reduction in demand for fossil fuels at any given price. The indirect effect is the reduction in the current equilibrium price for fossil fuels, which tends to increase the amount of fossil fuels demanded. Whether the sum of the two effects will actually result in an earlier or later date of exhaustion of the stock of fossil fuels depends on the curvature of the demand curve for energy and of the supply curve for the renewable substitute.     

Appraisal of coastal recreational resources in Qingdao by travel cost method

This paper serves to appraise the monetary cost of coastal recreational resources in Qingdao using the travel cost method (TCM), which is typically used in developed countries. The total revenue produced by Qingdao’s coastal recreational resources is about RMB 5.51×10¹⁰ annually, based on questionnaires given at Qingdao’s major tourist destinations. These questionnaires establish correlation functions that factor in the number of tourists, travel expenses, etc. The data processing software named Eviews was used to determine the tourist demand regression curve and to calculate their residual and actual travel expenses. The results of this study can provide a scientific basis for applicable industries interested in development and management decision-making. Therefore, this study assesses the reasonable usage of coastal recreational resources.     

Substitution between biofuels and fossil fuels: Is there a green paradox?

We show that (i) subsidies for renewable energy policies with the intention of encouraging substitution away from fossil fuels may accentuate climate change damages by hastening fossil fuel extraction, and that (ii) the opposite result holds under some specified conditions. We focus on the case of subsidies for renewable resources produced under increasing marginal costs, and assume that both the renewable resources and the fossil fuels are currently in use. Such subsidies have a direct effect and an indirect effect working in opposite directions. The direct effect is the reduction in demand for fossil fuels at any given price. The indirect effect is the reduction in the current equilibrium price for fossil fuels, which tends to increase the amount of fossil fuels demanded. Whether the sum of the two effects will actually result in an earlier or later date of exhaustion of the stock of fossil fuels depends on the curvature of the demand curve for energy and of the supply curve for the renewable substitute.     

Bayesian testing for trend in a power model for clustered binary data

Developmental toxicity studies are widely used to investigate the potential risk of environmental hazards. In dose–response experiments, subjects are randomly allocated to groups receiving various dose levels. Tests for trend are then often applied to assess possible dose effects. Recent techniques for risk assessment in this area are based on fitting dose–response models. The complexity of such studies implies a number of non-trivial challenges for model development and the construction of dose-related trend tests, including the hierarchical structure of the data, litter effects inducing extra variation, the functional form of the dose–response curve, the adverse event at dam or at fetus level, the inference paradigm, etc. The purpose of this paper is to propose a Bayesian trend test based on a non-linear power model for the dose effect and using an appropriate model for clustered binary data. Our work is motivated by the analysis of developmental toxicity studies, in which the offspring of exposed and control rodents are examined for defects. Simulations show the performance of the method over a number of samples generated under typical experimental conditions.     

Assessing the relative impacts of the factors affecting MIS adoption process

Micro-irrigation systems (MIS) have been at the forefront of policy-making and social research in exploring determinants that could potentially impact the adoption of MIS technologies in the field to fulfil the basic aim of enhanced agricultural productivity and enriched nutritional quality of the produce with optimal adoption of natural resources. Therefore, this study was undertaken to determine why MIS technologies have not been adopted to the extent anticipated, so that suitable policy schemes, promotional schemes and socio-technical frameworks could be formulated for their enhanced adoption to enhance the socio-economic status of the farming community in the Dahod district of Gujarat State, India. A study of 350 non-MIS (NMIS) and 350 MIS farmers was conducted to identify factors affecting the MIS adoption process. The logit model was fitted using XLSTAT software (XLSTAT 2014.1.04) to the explanatory variables (determinants) of the MIS adoption process. Type III analysis and ANOVA were conducted to test the relative significance of the explanatory variables adopted. It was found that total income had the highest weight (or beta coefficient, i.e. 0.625) followed by total land area (0.546), motor horsepower (0.499), dependency ratio (0.397), and education (0.295) and age of household head (0.207). Furthermore, to assess the efficacy of the logit model, the ROC curve was also developed and the AUC was found to be 0.881, and therefore the model was considered to discriminate well in identifying the factors affecting the MIS adoption process. The study found that higher total income and education level increase the likelihood of MIS adoption and agricultural water management, and therefore special training programmes on installation, as well as repair and maintenance, of MIS systems and agricultural water management can be planned at the institutional/organisation level. The total cultivable area is also one of the important determinants in MIS adoption, and therefore the adoption of MIS schemes should not be restricted to large farmers only, but rather should be extended to both small and marginal farmers.     

Fourth-corner generation of plant functional response groups

Plant functional response groups (PFGs) are now widely established as a tool to investigate plant—environment relationships. Different statistical methods to form PFGs are used in the literature. One way is to derive emergent groups by classifying species based on correlation of biological attributes and subjecting these groups to tests of response to environmental variables. Another way is to search for associations of occurrence data, environmental variables and trait data simultaneously. The fourth-corner method is one way to assess the relationships between single traits and habitat factors. We extended this statistical method to a generally applicable procedure for the generation of plant functional response groups by developing new randomization procedures for presence/absence data of plant communities. Previous PFG groupings used either predefined groups or emergent groups i.e. classifications based on correlations of biological attributes (Lavorel et al Trends Ecol Evol 12:474–478, 1997), of the global species pool and assessed their functional response. However, since not all PFGs might form emergent groups or may be known by experts, we used a permutation procedure to optimise functional grouping. We tested the method using an artificial test data set of virtual plants occurring in different disturbance treatments. Direct trait-treatment relationships as well as more complex associations are incorporated in the test data. Trait combinations responding to environmental variables could be clearly distinguished from non-responding combinations. The results are compared with the method suggested by Pillar (J Veg Sci 10:631–640) for the identification of plant functional groups. After exploring the statistical properties using an artificial data set, the method is applied to experimental data of a greenhouse experiment on the assemblage of plant communities. Four plant functional response groups are formed with regard to differences in soil fertility on the basis of the traits canopy height and spacer length.     

热解温度对生物炭循环伏安曲线特性的影响

随着生物炭在农业和环境领域的应用逐渐增多,生物炭对环境中生物化学过程的影响也日益加深.本文利用循环伏安曲线,探究了不同热解温度下生物炭的电子传递方式.结果发现,在热解温度为400℃时,生物炭的电导率较低,而循环伏安曲线上存在明显的氧化还原峰,这表明生物炭的电子传递方式以官能团的氧化还原反应过程为主.随着热解温度升高,以含氧官能团为主的氧化还原活性物质含量降低,氧化还原峰的峰电流降低;同时,生物炭比表面积增大、导电性增强,循环伏安曲线形状逐渐变为梭形,响应电流也逐渐增大;这表明生物炭的电子传递方式逐渐转变为主要依靠生物炭导电性的方式.总之,循环伏安曲线可以定性地分析生物炭的电子传递方式,为探究生物炭不同电子传递方式对生物化学过程的影响提供了一定的研究基础.