Toward estimating the value of stewardship volunteers: A cost-based valuation approach in King County,Washington, USA

Urban forestry professionals are increasingly challenged to find cost-effective strategies for resource conservation and management. Many organizations partner with citizen groups to host events that enlist volunteers to perform stewardship tasks like tree planting and trail maintenance. These volunteer programs incur costs to both the managing agency and partners, such as staffing, tools, and transportation. Volunteers contribute uncompensated time and expertise. Little is known about these contributions, yet citizen stewards and host groups represent an important human dimension of urban forest management. Using a survey administered to volunteers and host organizations at restoration events in King County Parks, WA, USA, we developed a cost-based approach to estimate the value of stewardship activities that occurred in the spring field season of 2011. Expenditures included volunteer and event host time and direct cost of traveling to and from events, on-site labor, equipment, and preparation costs. Results suggest that contributions made by volunteers and hosts are significant; the combined costs associated with the 17 sampled events was approximately $35,700. These efforts represent a small subset of the more than 1000 volunteer environmental stewardship activities that take place annually in King County.     

The grazing response of cattle to pasture contaminated with rabbit faeces and the implications for the transmission of paratuberculosis

Transmission of Mycobacterium avium subspecies paratuberculosis, the organism responsible for paratuberculosis (or Johne's disease) in ruminants, occurs through the faecal-oral route. As M. a. paratuberculosis has been isolated from rabbit faeces, cattle grazing rabbit faecal contaminated pasture may thus be at risk.A herd of 57 beef cattle was monitored on a farm in Perthshire, throughout the 1999 'grazing year', to investigate whether the cattle avoided rabbit faecal contaminated pasture and thus the potential for disease transmission. Grazing was measured every two days over eight rotations by sward heights on 40 marked treatment plots (0.5 m x 0.5 m) to which 0, 10, 50 and 250 rabbit faecal pellets were added. Cattle were also monitored by an active transponder system which enabled individual animals contacting two plots per field rotation (one control and one contaminated) to be recorded. During the monitored grazing year, grazing pressure was low with a net mean sward offtake of 18% of sward height per rotation. There were no significant differences between rabbit faecal treatments (0, 10, 50 and 250 pellets) with respect to the height or proportion of sward removed, or between the numbers of contacts made by cattle on contaminated and uncontaminated plots. Over 90% of all the cattle contacted contaminated plots, indicating that the potential for disease transmission was widespread among the herd.To our knowledge, this is the first reported instance of a lack of avoidance by grazing cattle towards swards contaminated with faeces, and implies that the potential for transmission of paratuberculosis from rabbit contaminated pasture is high.     

橡胶树体胚再生试管改进及其对植株再生和移栽的影响

本研究以巴西橡胶树[Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.]22个3年生的半同胞子代群体(即半同胞家系)为材料,并同时在巴西圣保罗州的沃图波兰加(Votuporanga)、平多拉马(Pindorama)及雅乌(Jaú)设置试验点对其6个乳管性状的遗传变异及选择进展进行了分析评估。6个乳管性状包括干胶产量(Pp)、树皮厚度(Bt)、乳管列数(Lv)、相邻乳管列之间的平均距离(Dc)、乳管密度(平均每5 mm长乳管列的乳管数,Dd),以及乳管口径(Di)。3个试验点的联合分析结果显示,除Lv之外,所有性状的地点效应及家系×地点互作效应均达极显著水平。6个性状中,以Bt的单株遗传力最高,Lv、Pp及Dc中等,Dd较低,Di最低。分析结果还显示,性状Pp与所有其它性状之间均存在极显著正相关。就Pp而言,当从参试的全部半同胞家系中遴选出5个表现最优的家系时,该性状的遗传增益为24.91%,而当从某一家系中选择出2个最佳单株时,其遗传增益可达30.98%。     

洞庭湖区水稻侧条施肥技术应用与展望

环保型农业在我国已呈雨后春笋之势,将环境效益列为首位的水稻侧条施肥技术也在洞庭湖区得以较为广泛的应用,但这一技术在进一步深入推广过程中仍然存在一些问题,如农户认知程度不高,技术壁垒制约,缺乏相应补偿机制等。从当前推广现状人手,结合国外先进经验,分析了洞庭湖区水稻侧条施肥技术推广中存在的问题,并针对性地提出解决对策,旨在为当地环保型农业技术的推广应用探索方向。     

鸡场土壤中大肠杆菌的检测与化学消毒剂筛选

应用平板计数法和大肠菌群最大或然数(MPN)法对44份养鸡场土壤样品污染情况进行测定,结果表明春秋季土壤污染较夏冬季严重;以从养鸡场土壤样品中分离鉴定的大肠杆菌作为指示菌,对戊二醛和二氧化氯的杀菌效力进行了测定,定量悬浮试验结果表明0.01％戊二醛作用30 min、0.02％戊二醛作用5 min、25 mg/L二氧化氯作用10 min,对大肠杆菌的杀灭率均达到100％.以土壤为载体的消毒试验结果表明0.01％戊二醛作用30 min、0.02％戊二醛作用10 min和300 mg/L二氧化氯作用30 min、400 mg/L二氧化氯作用10 min,对大肠杆菌的杀灭率均达到100％,两种消毒剂均具有良好的杀灭效果.     

谷物及其制品中隐蔽型真菌毒素的污染及检测技术研究进展

隐蔽型真菌毒素是真菌毒素与谷物基质成分或其他食品组分结合形成的一类强极性结合态真菌毒素,此类毒素在常规的分析方法中检测不到,人和动物摄入后在肠道内水解为毒素单体而发挥毒性作用。目前发现的隐蔽型真菌毒素主要有DON3G、DON15G、ZEN14G、ZEN14S和HFB1、HFB2、HFB3等。对隐蔽型真菌毒素在谷物及其制品中的产生、迁移转化、检测及对人类健康的影响进行了综述,以供参考。     

浅谈雾霾天气的环境毒理效应

2013年1月5日至26日,全国多地出现雾霾天气,长三角、珠三角和京津冀等地区尤其严重。导致雾霾天气形成的一个重要因素就是空气中颗粒物含量的不断增加。颗粒物粒径越小,其吸附有害污染物的能力越强,危害程度越大。因此,探寻控制颗粒物产生、减少雾霾天气的途径十分重要。该文从雾霾的组成入手,分析雾霾天气形成的主要原因及其毒理学效应,并提出应对措施。     

水口库区叶绿素a含量与环境因子的关系

以2012年水口库区全年的监测数据为依据,应用SPSS软件通过主成分分析和多元线性回归方法分析了春、夏、秋、冬四季叶绿素a与环境因子的关系。结果表明：高锰酸盐指数和五日生化需氧量在春、夏、秋、冬四季对叶绿素a都具有显著影响。其中,pH、溶解氧、高锰酸盐指数、五日生化耗氧量和悬浮物对春季叶绿素a含量具有显著影响;总氮、总磷、氨氮、亚硝酸盐氮、悬浮物、高锰酸盐指数和五日生化耗氧量对夏季叶绿素a含量具有显著影响;溶解氧、氨氮、高锰酸盐指数和五日生化耗氧量对秋季叶绿素a含量具有显著影响;高锰酸盐指数、五日生化耗氧量和悬浮物对冬季叶绿素a含量具有显著影响。     

昆虫神经肽Corazonin及其受体的研究进展

昆虫神经肽Corazonin是由11个氨基酸组成的结构非常保守的短肽,除在极大部分昆虫中是由前侧脑的神经元分泌外,也发现在少部分昆虫中是由腹部和食管下神经元分泌。Corazonin广泛存在于昆虫纲动物中,在不同昆虫中行使心率加速、体色改变、物质代谢增减、发育与生理节律调控、蜕皮延迟、吐丝减少等非常广泛的生理功能。介导Corazonin作用的Cora-zonin受体是典型的G蛋白偶联受体,定位在细胞膜上,在昆虫系统进化过程中具有一定的保守性。本文概述了昆虫Corazonin的发现、分泌、结构、生理功能及其受体的研究进展情况,归纳了研究中存在的争议,并在此基础上对其在广泛功能分化、对昆虫生存意义、胁迫环境下的生理与生化功能、受体结构功能与信号转导机制等方面的研究前景进行了展望。     

西双版纳农村村寨环境污染综合治理模式研究

通过对西双版纳两个不同民族村寨环境污染治理工作的尝试,认为生活污水、生活垃圾及禽畜粪便是造成村寨环境污染的主要原因,通过修建人工湿地净化生活污水、修建垃圾池用来固定垃圾投放地点及牲畜实行圈养等措施,使村寨的环境得到了较大的改善。为了更好地开展这一工作,提出了明确管理主体、进行宣传、加大资金投入力度和改变村民传统观念等四点管理措施。该研究可为有关部门开展农村村寨环境治理提供一定的参考。