Nutrient criteria for lakes,ponds, and reservoirs: A Bayesian TREED model approach

We develop regional-scale eutrophication models for lakes, ponds, and reservoirs to investigate the link between nutrients and chlorophyll-a. The Bayesian TREED (BTREED) model approach allows association of multiple environmental stressors with biological responses, and quantification of uncertainty sources in the empirical water quality model. Nutrient data for lakes, ponds, and reservoirs across the United States were obtained from the Environmental Protection Agency (EPA) National Nutrient Criteria Database. The nutrient data consist of measurements for both stressor variables (such as total nitrogen and total phosphorus), and response variables (such as chlorophyll-a), used in the BTREED model. Markov chain Monte Carlo (McMC) posterior exploration guides a stochastic search through a rich suite of candidate trees toward models that better fit the data. The Bayes factor provides a goodness of fit criterion for comparison of resultant models. We randomly split the data into training and test sets; the training data were used in model estimation, and the test data were used to evaluate out-of-sample predictive performance of the model. An average relative efficiency of 1.02 between the training and test data for the four highest log-likelihood models suggests good out-of-sample predictive performance. Reduced model uncertainty relative to over-parameterized alternative models makes the BTREED models useful for nutrient criteria development, providing the link between nutrient stressors and meaningful eutrophication response.     

Quantifying Eradication Success: the Removal of Feral Pigs from Santa Cruz Island, California

Abstract:  A major challenge facing pest-eradication efforts is determining when eradication has been achieved. When the pest can no longer be detected, managers have to decide whether the pest has actually been eliminated and hence to decide when to terminate the eradication program. For most eradication programs, this decision entails considerable risk and is the largest single issue facing managers of such programs. We addressed this issue for an eradication program of feral pigs ( Sus scrofa ) from Santa Cruz Island, California. Using a Bayesian approach, we estimated the degree of confidence in the success of the eradication program at the point when monitoring failed to detect any more pigs. Catch-effort modeling of the hunting effort required to dispatch pigs during the eradication program was used to determine the relationship between detection probability and searching effort for different hunting methods. We then used these relationships to estimate the amount of monitoring effort required to declare eradication successful with criteria that either set a threshold for the probability that pigs remained undetected (type I error) or minimized the net expected costs of the eradication program (cost of type I and II errors). For aerial and ground-based monitoring techniques, the amount of search effort required to declare eradication successful on the basis of either criterion was highly dependent on the prior belief in the success of the program unless monitoring intensities exceeded 30 km of searching effort per square kilometer of search area for aerial monitoring and, equivalently, 38 km for ground monitoring. Calculation of these criteria to gauge the success of eradication should form an essential component of any eradication program as it allows for a transparent assessment of the risks inherent in the decision to terminate the program.     

生态型抑尘剂的选择与实验模拟研究

根据露天矿汽车运输土质路面扬尘的发生机理,从环境本底条件出发,建立了粘结、凝并、吸湿、保水等抑尘因子的选择原则,确定了抑尘因子并对其进行了粘度、吸湿、高温抗蒸发及研磨抗辗压等实验模拟,在露天矿主要运输道路和放矿平台进行了应用.结果表明,由可溶性淀粉、硅酸钠和丙三醇组成的抑尘剂,粘度可达5 10mPa·s,粉尘的饱和吸剂率达到64 6% ,恒高温(4 5℃)下单位面积的蒸发速率为0 3kg·m- 2 ·h- 1 ,抗蒸发时间达65 17h ,具有强的粘结、凝并、吸湿、保水、抗高温和固结路面等性能,而且吸附性强,当一次喷洒量为0 5～1 0L·m- 2 时,可有效抑尘5d .     

核废料深埋处理安全性分析的热-水-力耦合模型新进展

本文介绍了国际合作项目ＤＥＣＯＶＡＬＥＸ在核废料深埋处理安全性分析的热—水—力耦合模型研究方面的新进展。     

浅论"三表合一"的设想

对国家环保总局提出的"三表合一"的设想,从三个方面提出自己的观点。第一,应以排污申报登记核定为基础,客观建立污染源动态数据库;第二,"三表合一"应该是环境统计报表、排污收费报表、污染控制报表等各方面污染源的数据统一到排污申报登记报表;第三,"三表合一"首先应建立统一的污染源指标体系,统一的污染测算方法和统一的基础数据库。     

A HYDROCLIMATIC APPLICATION STRATEGY FOR THE POISSON PARTIAL DURATION MODEL1

ABSTRACT: A strategy for formulating and testing the Poisson partial duration extreme value model is presented. The procedure is demonstrated using recorded Streamflow series from a humid subtropical region of the southern United States. The observed data series are partitioned by climatic causes and tested for both the Poisson assumption and the validity of the exponential as marginal distributions. Several statistical tests are utilized in making these determinations. Some important aspects of the model as applied to humid climates are demonstrated. It was found that a majority of Streamflow series could be represented by the model and that significant differences do exist between the arrival structures of floods resulting from different climatic mechanisms. However, these differences generally do not exist in the distribution of the flood magnitudes. In addition, it is possible that model validity is restricted by drainage basin size.     

AN IRRIGATION SCHEDULING MODEL WHICH INCORPORATES RAINFALL PREDICTIONS1

ABSTRACT In humid areas appreciable amounts of rainfall complicate irrigation scheduling. This rainfall tends to give supplemental water application a low priority. As a result irrigation may be delayed until there is not enough time to cover the crop area before some drought damage occurs. To improve the management of irrigation systems, a scheduling model has been developed. The model's water application decisions incorporate climatological records, soil-plant data, current pan evaporation and rainfall, the number of fields to be irrigated, and 5-day weather forecasts. The model updates the soil moisture conditions, predicts impending water depletion, and if supplemental water is needed both the field priority and amount to be applied is indicated for each of the next 5 days. Errors introduced through the use of forecasts and long-term pan evaporation records have been slight because of the tri-weekly updating. Also natural rains which restore the root zone to maximum water holding capacity prevent long-term bias.     

硫化矿石堆自燃预测预报技术

笔者在参考大量有关煤炭自燃理论研究成果的基础上,结合国内外关于硫化矿石氧化自燃的研究现状,对硫化矿石堆自燃的预测预报技术进行系统分析。概述硫化矿石氧化自热的机理;详细介绍硫化矿石的自燃倾向性测试、综合因素评价、统计经验法等预测方法;找出煤炭与硫化矿石堆自燃过程的共性,提出了数学模型模拟预测方法;阐述了标志气体分析和测温两种预报方法。展望硫化矿石堆自燃预测预报技术对硫化矿山的安全生产具有重要的指导意义。     

Casualty treatment after earthquake disasters: development of a regional simulation model

This paper presents a new approach to the casualty treatment problem following a large-scale disaster, based on a mathematical model of how a regional health-care system responds to an earthquake event. The numbers and locations of casualties rescued alive, the scale of pre-hospital care, the post-earthquake hospital capacity, and the transport system are inputs to the model. The model simulates the movement of casualties from the stricken areas to hospitals. It predicts the number of casualties that die as well as other statistics about the health-care system response, such as waiting time before treatment. The model can be run with varying input assumptions to simulate alternative disaster response strategies. Preliminary runs demonstrate the potential of the model as a tool for planning and training.