Effectiveness of multiple release sites in reintroduction of Persian fallow deer

Releasing animals in more than one location may increase or decrease the probability of success of a reintroduction project, yet the question of how many release sites to use has received little attention. We used empirical data from the reintroduction program of the Persian fallow deer (Dama mesopotamica) (Galilee region in northern Israel) in an individual-based spatially explicit simulation model to assess the effects of releasing deer from multiple sites. We examined whether multiple release sites increase reintroduction success, and if so, whether the optimal number of sites for a given scenario can be determined and whether the outcome differs if animals are released alternately (i.e., the location of the release alternates yearly between sites) or consecutively (i.e., one release site is used for several years, then another is used, and so forth). We selected 8 potential release sites in addition to the original site and simulated the release of 180 individuals at a rate of 10 individuals per year in different combinations of the original site and 1-4 additional sites. In our model, releasing animals into the wild at multiple sites produced higher population growth and greater spatial expansion than releasing animals at only one site and a consecutive-release approach was superior to an alternate-release approach. We suggest that through the use of simulation modeling that is based on empirical data from previous releases, managers can make better-informed decisions regarding the use of multiple release sites and greatly improve the probability of reintroduction success.     

RIVERWARE: A GENERALIZED TOOL FOR COMPLEX RESERVOIR SYSTEM MODELING1

ABSTRACT: Water management agencies seek the next generation of modeling tools for planning and operating river basins. Previous site‐specific models such as U.S. Bureau of Reclamation's (USBR) Colorado River Simulation System and Tennessee Valley Authority's (TVA) Daily Scheduling Model have become obsolete; however, new models are difficult and expensive to develop and maintain. Previous generalized river basin modeling tools are limited in their ability to represent diverse physical system and operating policy details for a wide range of applications. RiverWare(tm), a new generalized river basin modeling tool, provides a construction kit for developing and running detailed, site‐specific models without the need to develop or maintain the supporting software within the water management agency. It includes an extensible library of modeling algorithms, several solvers, and a rich “language” for the expression of operating policy. Its point‐and‐click graphical interface facilitates model construction and execution, and communication of policies, assumptions and results to others. Applications developed and used by the TVA and the USBR demonstrate that a wide range of operational and planning problems on widely varying basins can be solved using this tool.     

烟气湍流效应对火灾图像探测的影响

烟气是火灾过程的重要物理现象,烟气的湍流效应是火灾图像探测的重要影响因素,分析了烟气湍流反应对火灾图像探测的影响,得出了一些烟气湍流效应的图像特征,为多参数特征的火灾探测提供了理论依据。     

世界食物安全态势及中国对策

本文阐述了世界食物安全现状及发展趋势,介绍了不同国家实现食物安全的模式及其政策选择,分析了中国食物安全成就及未来所面临的困境和挑战,根据国情并借鉴国际经验提出了中国实现21世纪国家食物安全可持续性的战略举措。     

火电厂烟气抬升的积分模型研究

根据流体力学的基本方程,考虑引起烟气抬升不同阶段的掺混原因,将产生的掺混率叠加导出一个简单的掺混函数,从而得到一个计算烟气抬升运动的积分模型,并与试验结果进行了比较。     

氯及氯胺灭活大肠杆菌的消毒动力学模型

分别研究了游离氯和一氯胺在pH7.0、20℃时对大肠杆菌的灭活作用,利用6种不同消毒动力学模型:Chick’slaw,Chick-Watson,Hom,Rational,Hom-Powerlaw,Selleckmodel对试验数据进行了拟合,通过对拟合结果的比较分析得出:在消毒剂符合一级衰减动力学情况下,游离氯和一氯胺灭活大肠杆菌的最佳拟合模型分别是3参数的Rational模型和2参数的Selleck模型.     

Performance and modeling studies of rotating biological contactor for treatment of vegetable oil wastewater

This study focuses on a lab-scale rotating biological contactor (RBC) treating vegetable oil wastewater with high BOD and COD. The fabricated RBC was checked for efficiency in degrading polluted wastewater under different operating conditions. The maximum removal efficiencies for BOD and COD were 95.75% and 89%, respectively. This high removal percentage was obtained with 30% submergence of 10 discs rotating at 8 rpm. For the first time, bio-kinetic models were applied to the experimental results for vegetable oil wastewater. The best fit was obtained with the modified Stover-Kincannon and Grau model. The saturation constant (K_s) values were 1.872 and 3.024 g/L/d for BOD and COD, respectively, for the modified Stover-Kincannon and Grau model. For the Grau second-order model, the saturation constant was 1.416 and 3.744 g/L/d for BOD and COD, respectively. The predicted effluent BOD and COD values of the modified Stover–Kincannon model fitted almost exactly with the experimental values. This clearly predicts that this model can be best used to predict effluent BOD and COD concentration in a Rotating Biological contactor treating vegetable oil wastewater. The kinetic parameters determined in this study can be used to improve the design and operation of continuous mode RBC systems.     

PM composition and source reconciliation in Mexico City

PM_2.5 and PM₁₀ were collected during 24-h sampling intervals from March 1st to 31st, 2006 during the MILAGRO campaign carried out in Mexico City's northern region, in order to determine their chemical composition, oxidative activity and the estimation of the source contributions during the sampling period by means of the chemical mass balance (CMB) receptor model. PM_2.5 concentrations ranged from 32 to 70 μg m⁻³ while that of PM10 did so from 51 to 132 μg m⁻³. The most abundant chemical species for both PM fractions were: OC, EC, SO₄²⁻, NO₃⁻, NH₄⁺, Si, Fe and Ca. The majority of the PM mass was comprised of carbon, up to about 52% and 30% of the PM2.5 and PM10, respectively. PM2.5 constituted more than 50% of PM10. The redox activity, assessed by the dithiothreitol (DTT) assay, was greater for PM_2.5 than for PM₁₀, and did not display significant differences during the sampling period. The PM_2.5 source reconciliation showed that in average, vehicle exhaust emissions were its most important source in an urban site with a 42% contribution, followed by re-suspended dust with 26%, secondary inorganic aerosols with 11%, and industrial emissions and food cooking with 10% each. These results had a good agreement with the Emission Inventory. In average, the greater mass concentration occurred during O₃S that corresponds to a wind shift initially with transport to the South but moving back to the North. Taken together these results show that PM chemical composition, oxidative potential, and source contribution is influenced by the meteorological conditions.     

北京市清水与再生水协同利用优化模型

开展协同利用清水与再生水的城市供水系统优化研究具有重要的科学意义和广阔的应用前景.为促进城市水资源高效利用,基于多水源转换关系以及再生水生产能力和利用潜力,构建了面向多区域多部门的城市清水与再生水协同利用优化模型,并以水资源严重短缺的北京市为例进行实证研究.设置规划方案基准情景和规划替代方案情景,分别优化了清水与再生水的协同利用方案以及再生水厂群的运行方案.在规划方案基准情景下,再生水占研究区用水总量的32%,分别占农业、工业、环境用水量的60%、30%和42%.海淀区和石景山区再生水供给矛盾将较为突出.相比之下,规划替代方案情景可以获得更高的经济效益,总效益增加6. 21亿元,同时能增加再生水利用量36. 59%、减少清水用量14. 02%.规划替代方案能更加充分地利用现有设施,促进水资源循环利用.此外,还提供了在现有设施条件下,再生水利用量由政策规划值逐渐提升至最佳规模过程中再生水厂群的运行过渡方案.本文建立的研究方法具有较广泛的适用性,可用于解决其它具有再生水利用潜力地区的水资源短缺问题.