自动净化-高分辨气相色谱/高分辨质谱测定废气中二(口恶)英

采用自动净化-高分辨气相色谱/高分辨质谱(HRGC/HRMS)测定废气中的17种2,3,7,8位取代的多氯代二噁英和呋喃(PCDD/Fs)。废气样品经索氏提取,DEXTech系统全自动净化,浓缩和定容后,以HRGC/HRMS对废气样品中的PCDD/Fs进行了定性和定量分析。结果表明,17种二噁英和呋喃采样内标平均回收率为93%~99%,提取内标平均回收率为80%~97%;17种二噁英和呋喃自动净化实测结果与手工净化测试结果基本一致。该方法不但满足相关国家标准要求,还极大提高了样品的净化速度,减少人体对有机试剂的暴露。     

Sperm removal and ejaculate size correlate with chelae asymmetry in a freshwater crayfish species

Asymmetry in traits of sexual relevance may impair copulation behaviour and sexual performance of males, ultimately resulting in a fitness cost. Freshwater crayfish males use chelae, a sexually selected trait, to secure and position the female prior to and during mating. Thus, a relatively large chelae asymmetry, resulting from accidental loss and regeneration of one cheliped after autotomy, could have great consequences for male sexual behaviour. We studied copulatory behaviour and sperm expenditure of males paired to a mated female in Austropotamobius italicus, a freshwater crayfish species where both male and female mate multiply and where last-mating males are able to actively remove previously deposited sperm. We aimed at assessing whether male sperm removal and expenditure varied according to sperm allocated by first-mating males, and according to copulation behaviour and phenotypic traits (carapace length, chelae length and relative chelae asymmetry) of second-mating males. Second-mating males did not adjust their ejaculate size in relation to first-mating male ejaculate, nor to the first-mating male’s sperm removed. Moreover, the amount of sperm removed by second-mating males increased with increasing first-mating males ejaculate size, and first-mating male sperm remaining after removal did not correlate with the original first-mating male ejaculate size. Interestingly, the amount of sperm removed by second-mating males decreased with increasing relative chelae asymmetry, while increasing with male body size. However, second-mating (but not first-mating) asymmetric-clawed males produced larger ejaculates than symmetric-clawed ones. Importantly, the proportion of second-mating male sperm remaining after the two matings did not vary with relative chelae asymmetry nor with body size of second-mating males. Thus, small, asymmetric-clawed crayfish males appear to adopt sperm allocation tactics that allow them to fully compensate for their inferior sperm removal ability.     

Maternal energy expenditure does not change with flight costs or food availability in the pied flycatcher (Ficedula hypoleuca): costs and benefits for nestlings

We manipulated parental work load without changing brood size in a population of pied flycatchers Ficedula hypoleuca by removing two primaries (7 and 9) from each wing of females, thus reducing wing area and increasing flight costs. At other nests, we offered supplementary food in the form of live mealworms (10–20 g daily from hatching) to reduce brood demand and thus parental foraging costs. Other nests were left as controls. The daily energy expenditure of females feeding 12-day-old nestlings was measured with doubly labelled water D₂ ¹⁸O. Females in both treatments expended the same amount of energy, fed at the same rate and had similar body masses to birds in the control group. No effect of treatment on male mass and feeding effort was detected. More nestlings, however, died in nests of handicapped females. Nestlings of handicapped females had significantly lower body mass and haematocrit values than nestlings in food-supplemented nests, with nestlings in control nests occupying an intermediate position. The effects of both treatments on nestling mass, haematocrit values and mortality rates were only noticeable in nests infested with mites. Maternal energy expenditure is apparently constrained and offspring pay the costs imposed by reduced provisioning rate or increased demand caused by ectoparasites, while receiving benefits when food supply improves. The presumption that avian reproductive costs derive from changes in a flexible energy output may not be met in many cases. Received: 24 October 1998 / Received in revised form: 15 March 1999 / Accepted: 26 April 1999     

基于支付能力与支付意愿的居民生活用水水价承受能力研究——以广州市番禺区为例

从支付能力和支付意愿的角度,应用扩展线性支出系统(ELES)模型和条件价值评估法(CVM),定量研究居民生活用水水价承受能力.以广州市番禺区为例,通过2005~2009年截面数据资料和问卷调查数据,定量研究了城镇和农村居民生活用水水价支付能力和支付意愿,并分析了2011年番禺区居民对新调整居民生活用水水价的承受能力.结果表明,2005~2009年,达到平均收入水平的番禺区居民对水价具有支付能力,其基本用水需求能得到满足,但低收入户,尤其是农村低收入户的水价支付能力有限,是水价改革应重点关注的对象;CVM调查结果显示,番禺区居民对2011年生活用水水价的支付意愿为2.163元/m3;2011年,番禺区居民生活用水价格由2.00元/m3上调为2.15元/m3,达到平均收入水平的番禺区居民对新水价具有承受能力.     

Effects of female mating status on copulation behaviour and sperm expenditure in the freshwater crayfish <Emphasis Type="Italic">Austropotamobius italicus</Emphasis>

Sperm competition models predict that males should adjust their sperm expenditure according to the risk and/or intensity of sperm competition. In this paper, we analysed copulatory behaviour of both sexes and sperm expenditure in relation to female mating status (virgin or mated) in the freshwater crayfish Austropotamobius italicus, a species where males have been reported to feed on and remove sperm laid by other males. The same females were allowed to be inseminated sequentially by two males, and we compared the sexual behaviours of partners between the first (virgin females) and the second mating (mated females). We found that female resistance did not differ between the first and the second mating, nor males refused or took more time to mount a mated female. However, when mating with a mated female, males reached an effective copulation position significantly later. This occurred because second-mating males removed, by eating, all or most spermatophores previously deposited by first males. As removal was often incomplete, this resulted in a larger amount of sperm being deposited on female ventral parts after the second mating, although second males did not allocate more sperm to mated females than first males did. Thus, the peculiar mode of sperm competition, where males remove previously deposited sperm, and the consequent predictable strong last male prevalence in paternity likely led to the observed lack of adjustment of sperm expenditure to female mating status in this species.     

Survey of Levels of Phthalate Ester Plasticizers in a Sewage Lagoon Effluent and a Receiving Stream

In this study, samples from a sewage treatment lagoon and those from a receiving stream were analyzed for their phthalate esters content. Knowledge of the distribution of ubiquitous phthalate esters in the sewage lagoon and the receiving stream was necessary because of the reports of their subtle toxicity to aquatic biota and humans. Liquid–liquid extraction, Clean-up experiment and High Performance Liquid Chromatography (HPLC) were the methods employed for the quantitative determination of the Phthalates. A study of uncontaminated water was done to establish blank levels. The sewage lagoon and the receiving stream were grossly polluted as several phthalate ester plasticizers: DMP, DEP, DPhP, DBP, DEHP, DOP and DINP were found present at monthly mean levels of between 24.02 mg/L and 139.25 mg/L in the sewage treatment lagoon and 10.41 mg/L and 80.53 mg/L in the receiving stream. The results showed higher levels of phthalate esters in the sewage lagoon compared to the receiving stream. The sewage lagoon was identified as a pollution point source into the receiving stream. Levels of phthalates obtained from the receiving stream are much higher than the water criteria of 3 μg/L phthalates recommended by the United States Environmental Protection Agency (USEPA) for the protection of fish and other aquatic life in water and the Suggested No-Adverse Effect Levels (SNAEL) of 7.5–38.5 μg/L for drinking water. This should give cause for great environmental concern. Peoples’ health downstream is at stake and so is the ‘health’ of the ecosystem.     

Cardiovascular Strain of Sawmill Workers in South-Western Nigeria

This study aimed to assess cardiovascular strain during sawmilling operations in terms of physical workload, based on heart rate changes. We measured resting and working heart rates and calculated cardiovascular load (%CVL), cardiovascular strain (%CVS) and relative heart rate (%RHR) in 35 sawmill workers. Based on heart rate only, the work in sawmills was classified as very heavy and extremely heavy. Similarly, a high-level category was recorded for %CVL and a very high range for %CVS. Thus, the workload in sawmill operations is usually very high and can lead to physiological strain of the workers. There is a need to redesign the work content of this occupation to prevent excessive strain in the workers, as this will increase their productivity and reduce their health risk.     

宁波市水资源可持续利用的经济分析

随着经济社会的快速发展,宁波水资源短缺矛盾日益突出,通过对宁波市历年的水价、人均用水量、人均可支配收入的变化的分析可以看出水价与用水量的关系,重点探讨了引进市场机制,建立水权转让制度,改革水资源价格和水资源的开发管理方式,实行水资源的有偿使用和转让,优化配置水资源,提高水资源的使用效率和效益,以水资源的可持续利用支撑经济和社会的可持续发展.     

Public expenditure and the environmental management of Brazilian municipalities: a panel data model

Environmental expenditure can be classified as an indicator to measure the efforts of public agents with the environment. Cities and countries seek to understand the determinants of environmental spending over time. This research aims to analyze the variables that influence the environmental spending of Brazilian municipalities between the years 2012 and 2016. Thus, this research helps fill the gap on lack of longitudinal research that involves local contexts in relation to public municipal expenditures on the environment. The research method consists of the panel data model. Data were collected on the environmental expenditures of the municipalities and other variables of 4269 Brazilian municipalities, the collection generated 21,329 observations. The results showed that the municipalities of the state of Amapá had better relative expenditure averages, it was also observed that the municipalities in the Northeast region show the worst results. The municipality of Itamaracá, located in the state of Pernambuco, presented the best percentage of the country, 9.47% of the environmental expenditure in relation to total expenditure. Regarding the results of panel data, the variables revenue, population, density, GDP, and HDI presented significance in all models; the models estimated by fixed effects ensure the consistency of the parameters.     

我国环保产业科技投入机制研究

在分析科技投入体系的构成及环保科技投入的衡量指标基础上,研究政府和企业分别在环保产业科技投入体制中的机制;结论显示:必须强调企业科技投入的主体作用,并发挥其纽带作用;政府直接支持的科技投入具有杠杆作用,能够支持、引导和鼓励环保企业的研发投入。