大气汞的来源及其浓度分布特征研究进展

大气汞是全球性的污染物,其来源有自然源和人为源,亚洲地区是最大的人为大气汞排放源,占全球人为排汞量的67％(质量分数),其中又以中国为最.燃煤和有色金属冶炼对中国大气汞排放的贡献最大.环境界面的释汞通量是全球大气汞预算的重要组成部分,也是目前的研究热点之一.综述了不同环境界面的释汞通量及其影响因素,并比较了不同地区大气...     

论中国生态农业建设的五个基本问题

在最近的10年间,中国生态农业建设迅速发展,现已成为中国农村发展中一个不可分割的重要部分。生态农业建设利用生态经济学原理及系统工程学方法进行农业规划、设计和管理,寻求农村持续、稳定、协调的发展。本文从资源管理的角度讨论了中国生态农业建设的5个基本问题:经济规模、农民接受程度、市场、资金和可持续发展的方向。     

Determining When to Change Course in Management Actions

Time is of the essence in conservation biology. To secure the persistence of a species, we need to understand how to balance time spent among different management actions. A new and simple method to test the efficacy of a range of conservation actions is required. Thus, we devised a general theoretical framework to help determine whether to test a new action and when to cease a trial and revert to an existing action if the new action did not perform well. The framework involves constructing a general population model under the different management actions and specifying a management objective. By maximizing the management objective, we could generate an analytical solution that identifies the optimal timing of when to change management action. We applied the analytical solution to the case of the Christmas Island pipistrelle bat (Pipistrelle murrayi), a species for which captive breeding might have prevented its extinction. For this case, we used our model to determine whether to start a captive breeding program and when to stop a captive breeding program and revert to managing the species in the wild, given that the management goal is to maximize the chance of reaching a target wild population size. For the pipistrelle bat, captive breeding was to start immediately and it was desirable to place the species in captivity for the entire management period. The optimal time to revert to managing the species in the wild was driven by several key parameters, including the management goal, management time frame, and the growth rates of the population under different management actions. Knowing when to change management actions can help conservation managers’ act in a timely fashion to avoid species extinction. Determinar Cuándo Cambiar el Rumbo en las Acciones de Manejo     

Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae)

Abstract: River‐dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62‐year‐long (1948–2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30–40 years.     

生态建设人力资源开发战略和措施

生态建设本质和能力核心就是生产要素筹集配置能力和工程技术能力，因而生态建设受人力资源素质状态影响极大。本文深刻揭示生态建设人力资源规律和时空动态，对人力资源在生态建设角色、地位、作用、特征、人力资源的属性，对人力资源开发的影响因素、难点、重点、策略和措施等予以深刻而独到剖析；为各级政府、企业事业单位、社会团体从事生态建设人力资源开发，培养高素质生态建设活动组织者、指挥者、经营者和大量实用型技术人才提供依据和指导。     

固体火箭发动机沿海环境适应性分析

为提高导弹武器环境适应性,针对沿海地区的气候环境特点,分析了高温、高湿、湿热、盐雾、霉菌和辐射等典型环境条件对固体火箭发动机薄弱环节的影响,结合研制和作战使用的实际,提出了改进导弹武器装备沿海环境适应性的方法.     

依法发展再生资源产业——对《再生资源回收管理办法》的解读与思考

依法发展再生资源产业是推行循环经济的必然要求。解读《再生资源回收管理办法,》认为实现再生资源产业的全面发展,还需建立健全再生资源法律体系。     

Intergenerational Impartiality: Replacing Discounting by Probability Weighting

Intergenerational impartiality requires putting the welfare of future generations at par with that of our own. However, rational choice requires weighting all welfare values by the respective probabilities of realization. As the risk of non-survival of mankind is strictly positive for all time periods and as the probability of non-survival is cumulative, the probability weights operate like discount factors, though justified on a morally justifiable and completely different ground. Impartial intertemporal welfare maximization is acceptable, though the welfare of people in the very far future has lower effects as the probabilities of their existence are also lower. However, the effective discount rate on future welfare values (distinct from monetary values) justified on this ground is likely to be less than 0.1 per annum. Such discounting does not compromise environmental protection and sustainability unduly. The finiteness of our universe implies that the sum of our expected welfare to infinity remains finite, solving the paradox of having to compare different infinite values in optimal growth/conservation theories.     

Experimental investigation of the effect of sediment transport patterns on the adsorption of cadmium ions onto sediment particles

The mechanism of flow turbulence, sediment supply conditions, and sediment transport patterns that affect the adsorption of cadmium ions onto sediment particles in natural waters are experimentally simulated and studied in this study both in batch reactors and in a turbulence simulation tank. By changing the agitation conditions, the sediment transport in batch reactors can be categorized into bottom sediment-dominated sediment and suspended sediment-dominated sediment. It is found that the adsorption rate of bottom sediment is much less than that of suspended sediment, but the sediment transport pattern does not affect the final (equilibrium) concentration of dissolved cadmium. This result indicates that the parameters of an adsorption isotherm are the same regardless of the sediment transport pattern. In the turbulence simulation tank, the turbulence is generated by harmonic grid-stirred motions, and the turbulence intensity is quantified in terms of eddy diffusivity, which is equal to 9.84F(F is the harmonic vibration frequency) and is comparable to natural surface water conditions.When the turbulence intensity of flow is low and sediment particles stay as bottom sediment, the adsorption rate is significantly low, and the adsorption quantity compared with that of suspended sediment is negligible in the 6 h duration of the experiment. This result greatly favors the simplification of the numerical modeling of heavy metal pollutant transformation in natural rivers. When the turbulence intensity is high but bottom sediment persists, the rate and extent of descent of the dissolved cadmium concentration in the tank noticeably increase, and the time that is required to reach adsorption equilibrium also increases considerably due to the continuous exchange that occurs between the suspended sediment and the bottom sediment.A comparison of the results of the experiments in the batch reactor and those in the turbulence simulation tank reveals that the adsorption ability of the sediment, and in particular the adsorption rate, is greatly over-estimated in the batch reactor.     

EFFECTS OF BUILDING CONSTRUCTION NOISE ON RESIDENTS: A QUASI-EXPERIMENT

Noise pollution is an environmental problem in cities. Although recent field research has focused on transportation noises, the effects of exposure to building construction noise have not been studied. In a quasi-experiment, residents of a three-wing residence hall for female students located near a construction site served as subjects in three comparison groups. Information about their personal characteristics and perceived effects of construction noise on studying and other behaviours were gathered in a questionnaire (n=94) and an activity log (n=14). In addition, sound level measurements and records of resident turnover and systematic observations of windows open or closed were analysed. As expected, the results of chi-square tests, one-way ANOVAs and MANOVAs show significant wing effects (p<0·05) on frequency heard, distractability, and several perceived behavioural effects, such as being awakened, difficulty with relaxation and studying-related activities, and interference with conversation and television-watching. These effects were significantly more severe for residents closest to the construction site than those further away. Residents coped with noise by speaking louder, keeping windows closed, and leaving the room.