The Cost Efficiency of Wild Dog Conservation in South Africa

Abstract:  Aside from Kruger National Park, no other suitable reserves of sufficient size exist in South Africa that will hold a viable population of wild dogs ( Lycaon pictus ). Consequently, conservation efforts have been focused on creating a metapopulation through a series of wild dog reintroductions into isolated fenced reserves. Additional potential exists for conserving wild dogs on private ranch land. Establishing the metapopulation was an expensive process, accounting for approximately 75% of the US$380,000 spent on wild dog conservation in South Africa during 1997-2001. The principal goal of the metapopulation project was to reduce the risk of catastrophic population decline. Now that this has been achieved, we developed a uniform cost-efficiency index to estimate the cost efficiency of current and potential future conservation strategies in South Africa. Conserving wild dogs in large protected areas was predicted to be the most cost-efficient conservation strategy (449 packs/$100,000 expenditure). Establishing the metapopulation has been less cost efficient (23 packs/$100,000), and expansion of the metapopulation was predicted to be even less cost efficient if predation by wild dogs results in additional costs, as is to be expected if private reserves are used for reintroductions (3-13 packs/$100,000). Because of low logistical costs, conserving wild dogs in situ on private ranch land was potentially more cost efficient than reintroducing wild dogs (14-27 packs/$100,000). We recommend that donor funding be used to reintroduce wild dogs into transfrontier parks, when they are established, to maintain the existing metapopulation and to establish conservation programs involving wild dogs on private ranch land. Investing in the expansion of the metapopulation should be limited to state-owned nature reserves willing to carry predation costs without compensation.     

SO2在水和有机溶剂中的化学形态及其脂/水分配系数：SO2生理学研究新模式

为了探讨内源性SO2生理作用和毒理作用的化学机制,采用真空减压法、超声波法、通气法、光谱扫描法及摇瓶法等对SO2在水和有机溶剂中的化学形态及其脂/水分配系数进行了研究.研究结果表明:1)气态SO2不仅易溶于水,而且更易溶于有机溶剂;2)SO2在水和有机溶剂中的溶解主要是物理性溶解,其主要以SO2分子状态存在于溶液中,在饱和溶液中90%以上是以自由分子状态存在,在较低浓度下也有50%左右以自由分子状态存在;3)SO2的脂/水分配系数仅为0.16～0.20,使存在于生物膜(脂相)系统的内源性SO2很容易进入水相并转化为亚硫酸盐,这将导致其在组织细胞内的半寿期很短,这符合信号分子的特征.由此结论:1)以SO2生理盐水溶液作为SO2供体,可作为研究内源性SO2生理作用和毒理作用的新模式;2)内源性SO2在组织细胞内的失活途径是:SO2→SO32-/HSO3-→SO42-.此外,论文认为亚硫酸钠和亚硫酸氢钠混合液并不能作为"SO2供体"用以处理生物组织.     

浅析电子废弃物回收利用及危害解决办法

随着高科技的发展和人们需求的增长,电子产品不断推陈出新,电子废弃物成为世界上数量增长最快的垃圾."电子垃圾",主要包括各种使用后废弃的电脑、通信设备、电视机、电冰箱、洗衣机等电子电器产品.电子废弃物不规范回收处理易造成污染.电子废弃物中含有很多可回收再利用的有色金属、黑色金属、玻璃等物质.严格意义上讲,这些电子废弃物,不应称其为电子垃圾,而应称作电子旧货.伴随着电子工业的高速发展,电子废弃物污染不可避免地摆在了我们面前.电子废弃物具有危害性和可利用性.     

Stability analysis of alkaline nitrobenzene-containing wastewater by a catalyzed Fe-Cu treatment process

Iron and copper bimetallic system (catalyzed Fe-Cu process) is a promising technology for alkaline nitrobenzene-containing wastewater treatment. However, little is currently known about the changes of treatment efficiency with time going. This research investigated the long-term performance of the catalyzed Fe-Cu process to reduce nitrobenzene (NB) in alkaline wastewater. In addition, the changes of the metal surfaces morphologies and matters before and after the reaction were analyzed by scanning electron microscopy (SEM) in conjunction with energy-dispersion spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD). The results showed that the surface properties of copper almost remained unchanged after weeks of operation, which spelled its strong chemical stability and resistance to poisoning. Moreover, the results indicated that there were two reasons for the treatment efficiency decreasing with time. One was the gradual iron element consumption due to corrosion. The other was iron reactivity weakened due to the precipitates accumulation on the surfaces that were mainly Fe₃O₄ and FeCO. __________ Translated from Environmental Pollution & Control, 2006, 28(10): 783–785 [译自: 环境污染与防治]     

介质阻挡放电降解环境污染物CF2ClBr的等离子体系电子密度

在利用介质阻挡放电对污染物质ＣＦ２ＣｌＢｒ进行等离子体降解产物分析的基础上,进一步研究等离子体系中的电子密度。采用动态反应装置,以平行板电极法直接测量。在ＣＦ２ＣｌＢｒ的压力为２ｋＰａ时,得出该实验条件下的电子密度约为５．０×１０＾１３／ｍ＾３。     

The Characterisation of Settled Dust by Scanning Electron Microscopy and Energy Dispersive X-ray Analysis

Settled dust has been collected inside the main foyers ofthree University buildings in Wolverhampton City Centre,U.K. Two of the three buildings are located in a streetcanyon used almost exclusively by heavy duty dieselvehicles. The dust was collected on adhesive carbonspectro-tabs to be in a form suitable for analysis byscanning electron microscope and energy dispersive X-rayanalysis. Using these analytical techniques, individualparticle analysis was undertaken for morphology andchemistry. Seasonal variations and variations due tolocation were observed in both the morphologicalmeasurements and chemical analysis. Many of the differencesappear attributable to the influence of road traffic, inparticular, the heavy duty diesel vehicles, travellingalong the street canyon.     

辐射技术在水处理中的应用及其发展

介绍了水处理辐射技术的分类、处理机理及其特点;概括了辐射技术在水处理中的应用情况;分析了辐射技术在水处理中的发展趋势。     

Integrated energy view of wastewater treatment: A potential of electrochemical biodegradation

• Energy is needed to accelerate the biological wastewater treatment. • Electrical energy input in traditional technology is indirect and inefficient. • Direct injection of electricity can be a game changer to maximize energy efficiency. • Microbial electrochemical unit for decentralized wastewater treatment is proposed. It has been more than one century since the activated sludge process was invented. Despite its proven stability and reliability, the energy (especially the electrical energy) use in wastewater treatment should evolve to meet the increasingly urgent demand of energy efficiency. This paper discusses how the energy utilized in conventional biological wastewater treatment can be altered by switching the indirect energy input to a direct electricity injection, which is achieved by the electrode integration providing extra thermodynamic driving force to biodegradation. By using electrodes instead of oxygen as terminal electron acceptors, the electrical energy can be utilized more efficiently, and the key of direct use of electrical energy in biodegradation is the development of highly active electroactive biofilm and the increase of electron transfer between microbes and the electrode. Furthermore, the synergy of different microbial electrochemical units has additional benefit in energy and resource recovery, making wastewater treatment more sustainable.     

电子束辐照降解水体中的金霉素

应用电子加速器辐照研究了去除水体中金霉素（30mg/L）的过程,初步探索了剂量、不同气氛条件下叔丁醇的存在、pH值、无机阴离子等对去除效率的影响.然后根据实验结果推测了降解机理和降解产物毒性.结果表明：电子束辐照能高效去除水体中的金霉素,且还原性粒子占主导作用;pH值为碱性时利于金霉素的去除;0.005mol/LCO₃^2-、SO₄^2-、NO₃^-或Cl^-的存在能促进其去除.根据超高效液相色谱-质谱（UHPLC-MS）对降解产物的分析,并结合理论计算推测出10种降解产物和相应的降解途径.之后的费氏弧菌毒理实验数据显示：降解后水样的生物毒性随着吸收剂量先增高后缓慢降低,但辐照5.0kGy后毒性依然较大.     

不同制备温度的水稻生物炭电子交换能力研究

为探究不同热解温度下生物炭的电子交换能力,通过限氧升温炭化法,利用水稻秸秆在不同热解温度条件下制备生物炭,与氧气、铁氰化钾氧化剂和柠檬酸钛还原剂进行氧化还原反应,对生物炭的得电子能力（EAC）和失电子能力（EDC）进行定量分析.结果显示,热解温度对生物炭的电子交换能力有较大影响,随热解温度升高至500℃时,生物炭的EAC和EDC达到最大,分别为3.86,1.72mmol/g高于500℃后,随着温度的增加,EAC和EDC逐渐减小,这是由于生物炭的醌类和酚类官能团的结构改变以及持久性自由基强度变化的联合作用.此外,柠檬酸钛和连二硫酸钠两种氧化还原电位不同的还原剂进一步证实了还原剂电位对生物炭EAC的影响.且生物炭具有氧化还原的可逆性,可逆的EAC与EDC之和近似等于生物炭的电子储存能力.