Impact of Cloud on Net Ecosystem CO2 Exchange of Alpine Meadow in Tibetan Plateau

Meteorological elements and CO2 fluxes over alpine meadow ecosystem were observed continuously from 2004 to 2005in Damxung Alpine Meadow Flux Station,China Flux Network.Based on the eddy covariance CO2 fluxes and meteorological data obtained,the relationships among the CO2 fluxes,the cloud amount,and the meteorological factors in alpine meadow ecosystem were explored and analyzed.Some conclusions can be drawn from the discussion with previous researches as following:(1)the cloud amount can affect the net ecosystem CO2 exchange(NEE)of alpine meadow on Tibetan Plateau;(2)the soil temperature sensitive to the cloud amount,is a major environmental controlling factor for NEE,and closely relates to the maximum of NEE.In the morning period with large cloud amount,the NEE reaches its maximum when the clearness index ranges from 0.5 to 0.7; yet in the afternoon it comes to the maximum with the index from 0.2 to 0.35.The span of soil temperature covers from 12 to 15℃ as the NEE at its highest;(3)the scatterplots between NEE and photosynthetic available radiation(PAR)was a significant inverse triangle in the clear day,two different kinds of concave curves in the cloudy day,and strongly convergent rectangular hyperbola in the overcast day.These differences were controlled by the changes of light radiation and soil temperature.     

Smallholder Farms as Stepping Stone Corridors for Crop-Raiding Elephant in Northern Tanzania: Integration of Bayesian Expert System and Network Simulator

Crop-raiding elephants affect local livelihoods, undermining conservation efforts. Yet, crop-raiding patterns are poorly understood, making prediction and protection difficult. We hypothesized that raiding elephants use corridors between daytime refuges and farmland. Elephant counts, crop-raiding records, household surveys, Bayesian expert system, and least-cost path simulation were used to predict four alternative categories of daily corridors: (1) footpaths, (2) dry river beds, (3) stepping stones along scattered small farms, and (4) trajectories of shortest distance to refuges. The corridor alignments were compared in terms of their minimum cumulative resistance to elephant movement and related to crop-raiding zones quantified by a kernel density function. The “stepping stone” corridors predicted the crop-raiding patterns. Elephant presence was confirmed along these corridors, demonstrating that small farms located between refuges and contiguous farmland increase habitat connectivity for elephant. Our analysis successfully predicted elephant occurrence in farmland where daytime counts failed to detect nocturnal presence. These results have conservation management implications.     

Toward Integrative Management Advice of Water Quality, Oil Spills, and Fishery in the Gulf of Finland: A Bayesian Approach

Understanding and managing ecosystems affected by several anthropogenic stressors require methods that enable analyzing the joint effects of different factors in one framework. Further, as scientific knowledge about natural systems is loaded with uncertainty, it is essential that analyses are based on a probabilistic approach. We describe in this article about building a Bayesian decision model, which includes three stressors present in the Gulf of Finland. The outcome of the integrative model is a set of probability distributions for future nutrient concentrations, herring stock biomass, and achieving the water quality targets set by HELCOM Baltic Sea Action Plan. These distributions can then be used to derive the probability of reaching the management targets for each alternative combination of management actions.     

Growth and photosynthetic responses to copper in wild grapevine

The present study evaluates the tolerance and accumulation potential of Vitis vinifera ssp. sylvestris under moderate and high external Cu levels. A greenhouse experiment was conducted in order to investigate the effects of a range of external Cu concentrations (0–23 mmol L⁻¹) on growth and photosynthetic performance by measuring gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments. We also measured the total copper, nitrogen, phosphorus, sulphur, calcium, magnesium, iron, potassium and sodium concentrations in the plant tissues. All the experimental plants survived even with external Cu concentrations as high as 23 mmol L⁻¹ (1500 mg Cu L⁻¹), although the excess of metal resulted in a biomass reduction of 35%. The effects of Cu on growth were linked to a reduction in net photosynthesis, which may be related to the effect of the high concentration of the metal on photosynthetic electron transport. V. vinifera ssp. sylvestris survived with leaf Cu concentrations as high as 80 mg kg⁻¹ DW and growth parameters were unaffected by leaf tissue concentrations of 35 mg Cu kg⁻¹ DW. The results of our study indicate that plants of V. vinifera ssp. sylvestris from the studied population are more tolerant to Cu than the commercial varieties of grapevine that have been studied in the literature, and could constitute a basis for the genetic improvement of Cu tolerance in grapevine.     

基于双指标的安康水库防洪预报调度规则研究

随着水文预报水平的提高,考虑预报信息的防洪预报调度方式日益受到重视。对安康水库实施防洪预报调度的可行性进行了分析,采用“逐级调节法”反复试算修正,确定了以“预报累积净雨量”为主判断指标、“库水位”为辅助指标的安康水库双指标防洪预报调度规则,并对设计洪水及实际洪水进行了调节,调节结果与常规调度比较,水库水位提前降低至汛限水位以下,增加了防洪库容,减小了洪峰段下泄流量,降低了水库最高水位,提高了防洪能力。同时选择不同起调水位,对设计洪水及实际洪水进行调节, 确定合适起调水位,并分析了预报调度和常规调度的风险。结果显示：起调水位抬升,防洪预报调度的风险有所增加,但仍小于常规调度风险,为更好的实现洪水资源的有效利用,建议预报调度起调水位定为3260 m     

油气管道腐蚀可靠性的贝叶斯评价法

对油气管道腐蚀危害因素进行分析,建立其失效故障树。根据故障树分析原理,找出导致管道腐蚀穿孔破坏的23个因素。通过对故障树的定性分析,采用下行法求出油气管道腐蚀失效故障树的96个全部最小割集,并确定失效的主要影响因素。结合最小割集不相交化法和贝叶斯可靠性评定法对管道腐蚀失效进行定量分析,通过某油气管道事故统计数据,利用贝叶斯可靠性评定方法求出油气管道腐蚀可靠性的一阶矩和二阶矩。对一阶矩和二阶矩进行拟合,求出油气管道腐蚀可靠性的第一近似下限和第二近似下限。结果表明:得出的油气腐蚀管道贝叶斯可靠性评价结果可以指导管道系统的维护和维修,降低管道运行的风险。     

新疆空气质量日报网站数据传输管理系统的设计与实现

利用ASP.NET和ADO.NET技术开发的新疆空气质量日报网站数据传输管理系统,实现了网站空气质量日报的动态管理,同时依托该网站将沙尘暴天气应急监测数据传输系统作为其组成部分,使对新疆境内的区域大气质量监测数据的管理更加及时、高效,提高了工作效率,新疆的城市空气质量日报工作达到全国领先水平.本文对本系统的开发原理、系统的功能特点和设计方案进行了介绍.     

基于模糊Petri网的交通事故致因建模分析

针对目前我国道路交通事故多发的现状,以模糊Petri网为工具,以对道路交通安全有重大影响的关键因素为基础,模拟给出其因果关系,建立了基于模糊Petri网的道路交通事故致因分析模型,设计最长路径算法分析模型中某个致因要素导致交通事故发生的可信度。最长路径上的致因要素即为最易引起交通事故的主要因素。案例分析表明,这个模型能够体现各因素之间的逻辑关系,达到了通过数量指标分析道路交通事故主要原因的目的。     

Air Quality Management: Participatory Ranking of Control Measures and Conflict Analysis

The ranking of air quality control measures according to a number of evaluation criteria and with the participation of a large number of interested publics is demonstrated. A pilot study for the South Coast Air Quality Management District of California serves as the reference point. Several methodological considerations are addressed, such as: (a) the enhancement of criterion priorities to account for the variability among the performance of the control measures when incommensurable impact levels are applied: (b) the derivation of alternative rankings according to the priorities of potential coalitions; (c) the assessment of the potential acceptability of a collective ranking given the degree of solidarity among participants with similar interest affiliations; and (b) the assessment of the extent to which the performance of specific control measures may override priority differences and lead to insignificant ranking differences.     

Physical and Economic Sustainability of Water: New Approach Using the Case of the Big Lost River,Idaho

A new approach for evaluating water sustainability is introduced by comparing physical and economic sustainability. To achieve physical sustainability, water should be available in sufficient quantity and of good quality and used efficiently. The economic sustainability can be achieved by balancing between costs and values of water. The objectives of this study were to estimate the physical and economic sustainability of surface water in the Big Lost River, south–central Idaho. The study used a Bayesian network by building a graphical diagram of nodes representing all significant variables related with the sustainability, such as water demand, water quality, and the different costs and values of water. The study showed that the likelihood of the physical sustainability is less than that of the economic sustainability, which is attributed to the scarcity of water in the Big Lost River. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.