Extreme value analysis of Munich air pollution data

We present three different approaches to modelling extreme values of daily air pollution data. We fitted a generalized extreme value distribution to the monthly maxima of daily concentration measures. For the exceedances of a high threshold depending on the data, the parameters of the generalized Pareto distribution were estimated. Accounting for autocorrelation, clusters of exceedances were used. To obtain information about the relationship of the exceedance of the air quality standard and possible predictors we applied logistic regression. Results and their interpretation are given for daily average concentrations of ozone and nitrogen dioxide at two monitoring sites within the city of Munich.     

Empirical Bayes calculations of concordance between endpoints in environmental toxicity experiments

Hierarchical models are considered for estimating the probability of agreement between two outcomes or endpoints from an environmental toxicity experiment. Emphasis is placed on generalized regression models, under which the prior mean is related to a linear combination of explanatory variables via a monotone function. This function defines the scale over which the systematic effects are modelled as additive. Specific illustration is provided for the logistic link function. The hierarchical model employs a conjugate beta prior that leads to parametric empirical Bayes estimators of the individual agreement parameters. An example from environmental carcinogenesis illustrates the methods, with motivation derived from estimation of the concordance between two species carcinogenicity outcomes. Based on a large database of carcinogenicity studies, the inter-species concordance is seen to be reasonably informative, i.e. in the range 67–84%. Stratification into pertinent potency-related sub-groups via the logistic model is seen to improve concordance estimation: for environmental stimuli at the extremes of the potency spectrum, concordance can reach well above 90%.     

Robust benchmark dose determination based on profile score methods

We investigate several methods commonly used to obtain a benchmark dose and show that those based on full likelihood or profile likelihood methods might have severe shortcomings. We propose two new profile likelihood-based approaches which overcome these problems. Another contribution is the extension of the benchmark dose determination to non full likelihood models, such as quasi-likelihood, generalized estimating equations, which are widely used in settings such as developmental toxicity where clustered data are encountered. This widening of the scope of application is possible by the use of (robust) score statistics. Benchmark dose methods are applied to a data set from a developmental toxicity study.     

Assessment of China''''s economic loss resulting from the degradation of agricultural land in the end of 20th century

IntroductionUnderanintegratedactionofhumaneconomicactivitiesandsomeadversenaturalfactors,farmlanddegradationisadynamicprocessthatcanleadtoanunbalancingofecologicalsystems,worseningofsoilquality ,adeclineinsoilrenewablecapacity ,andaweakeningofsoilcarryingcapacity.Usually ,thedegradationofagriculturallandincludesadiminishingofvegetation ,soildeterioration ,andnaturaleco environmentaldegradation .Farmlanddeteriora tionhasatwofoldmeaning :qualityandquantity .Allofthephenomenaandprocessesbroughtab…     

兰州市空气污染对儿童呼吸疾病的影响

探讨兰州市空气污染对不同性别和年龄的儿童呼吸疾病就诊人数的影响以及季节性变化.通过收集2013~2017年兰州市空气污染物PM_2.5、PM₁₀、SO₂、NO₂、CO和O₃8h浓度数据、气象数据及3家三甲医院儿童呼吸疾病门诊资料,采用广义相加模型（GAM）控制星期几效应、气象因素、假期效应等混杂因素,分析空气污染物浓度与儿童呼吸系统疾病日门诊量的关系及滞后效应.研究期间,兰州市3家三甲医院儿童呼吸系统疾病日门诊量平均为387人次,范围1~1413人次.单污染物模型结果显示,PM_2.5、NO₂、SO₂、CO均在累积滞后一天（lag01）时效应量达到最大值,其浓度每增加10μg/m³（CO单位为1mg/m³）,儿童呼吸系统疾病就诊人次的超额危险度（ER）及95%可信区间（95% CI）分别为0.245%（95% CI：0.127%~0.363%）,0.568%（95% CI：0.327%~0.808%）,1.661%（95% CI：1.022%~2.302%）,2.245%（95% CI：1.610%~2.883%）;PM₁₀和O₃8h在各滞后天数均无统计学意义.对不同性别、年龄、季节分析发现,性别分层中PM_2.5对女童的影响略高于男童,NO₂、SO₂和CO的影响男童略高于女童;年龄分层发现PM_2.5、NO₂和CO的影响6~14岁组大于0~5岁组,SO₂的影响0~5岁组大于6~14岁组;季节分层中PM_2.5、NO₂、SO₂和CO对门诊量的影响只在冬季有意义,PM₁₀和O₃8h在各个季节均无意义.双污染物模型结果显示,分别调整其他5种污染物后,PM₁₀和O₃8h对儿童呼吸系统疾病门诊量的增加均无统计学意义;调整PM₁₀和O₃8h后,其他污染物呼吸系统疾病门诊量的增加均有统计学意义.兰州空气污染物（PM_2.5、NO₂、SO₂、CO）与呼吸系统疾病门诊量密切相关,并且SO₂和CO浓度增加更易增加儿童呼吸系统疾病的发病风险.性别、年龄和季节对空气污染物和呼吸系统疾病门诊就诊人次的关系有影响.     

Spatial effects and strategic behavior in a multiregional transboundary pollution dynamic game

We analyze a transboundary pollution differential game where pollution control is spatially distributed among a number of agents with predetermined spatial relationships. The analysis emphasizes, first, the effects of the different geographical relationships among decision makers; and second, the strategic behaviour of the agents. The dynamic game considers a pollution stock (the state variable) distributed among one large region divided in subregions which control their own emissions of pollutants. The emissions are also represented as distributed variables. The dynamics of the pollution stock is defined by a parabolic partial differential equation. We numerically characterize the feedback Nash equilibrium of a discrete-space model that still captures the spatial interactions among agents. We evaluate the impact of the strategic and spatially dynamic behaviour of the agents on the design of equilibrium environmental policies.     

Implications of network particle tracking (NPT) for ecological model interpretation

Network particle tracking (NPT), building on the foundation of network environ analysis (NEA), is a new development in the definition of coherence relations within and between connected systems. This paper evaluates three ecosystem models in a comparison of throughflow- and storage-based NEA and NPT. Compartments in models with high indirect effects and Finn cycling showed low correlation of NEA storage and throughflow with particle repeat visits and numbers of particles in compartments at steady state. Conversely, the correlation between NEA and NPT results was high with two models having lower indirect effects and Finn cycling. Analysis of ecological orientors associated with NEA showed NPT to fully support conventional NEA results when the common conditions of donor control and steady state are satisfied. Particle trajectories are recorded in the new concept of a particle “passport”. Ability to track and record particle in-system histories enables views of multiple scales and opens the possibility of making pathway-dependent modeling decisions. NPT may also enable modeling of time, allowing integration of Newtonian, organismal and stochastic modeling perspectives in a single comprehensive analysis.     

Loss of Large Predatory Sharks from the Mediterranean Sea

Abstract:  Evidence for severe declines in large predatory fishes is increasing around the world. Because of its long history of intense fishing, the Mediterranean Sea offers a unique perspective on fish population declines over historical timescales. We used a diverse set of records dating back to the early 19th and mid 20th century to reconstruct long-term population trends of large predatory sharks in the northwestern Mediterranean Sea. We compiled 9 time series of abundance indices from commercial and recreational fishery landings, scientific surveys, and sighting records. Generalized linear models were used to extract instantaneous rates of change from each data set, and a meta-analysis was conducted to compare population trends. Only 5 of the 20 species we considered had sufficient records for analysis. Hammerhead ( Sphyrna spp.), blue ( Prionace glauca ), mackerel ( Isurus oxyrinchus and Lamna nasus ), and thresher sharks ( Alopias vulpinus ) declined between 96 and 99.99% relative to their former abundance. According to World Conservation Union (IUCN) criteria, these species would be considered critically endangered. So far, the lack of quantitative population assessments has impeded shark conservation in the Mediterranean Sea. Our study fills this critical information gap, suggesting that current levels of exploitation put large sharks at risk of extinction in the Mediterranean Sea. Possible ecosystem effects of these losses involve a disruption of top-down control and a release of midlevel consumers.     

PRELIMINARY DESIGN AND COST ESTIMATING FOR RESERVOIR PROJECTS1

ABSTRACT: In estimating the costs of a reservoir project, it is difficult to produce accurate costs without performing a detailed design and quantity takeoff. The computerized procedure presented in this article provides a method for determining these planning level costs quickly and easily, while maintaining reasonable accuracy.