首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
This paper presents the trends of total ozone at Beijing and Kunming areas during the period of 1979 to 1989.The SBUV ozone vertical profile data and the periodic oscillation in upper ozone layers over Beijing area are also described.The results show that the variation of Beijing and Kunming per decade are about-5%and-1.5%.respectively.  相似文献   

2.
Since 1975, Wisconsin Electric has conducted impingement studies at seven steam electric, once-through cooling-equipped power plants, as well as at one closed-cycle cooling system-equipped plant. Entrainment studies were also conducted at all seven once-through cooling-equipped plants. All eight plants are located on the Great Lakes or on major tributaries to them. Two of the eight plants have since been retired, while portions of two remaining multi-unit plants have been retired.As part of the study reports ultimately filed with the state agencies overseeing the studies, companies were also required to provide information on: intake design, capacity, and operation; whether biocides were used at the plants to control biofouling; and what ice control measures were employed during the winter season. Companies were also asked to provide brief assessments of available intake design alternatives that could be reasonably expected to reduce entrainment or impingement, as well as order of magnitude cost estimates for retrofiting plants with feasible alternative technologies.The studies concluded that since the vast majority of fish impinged during the 1975–1976 period were alewife and rainbow smelt (the then most abundant species in Lakes Michigan and Superior) and since the historic commercial harvests of these two species greatly exceeded annual impingement estimates, the impact of these incremental losses to lake-wide populations was inconsequential. With respect to the entrainment results, the studies detected few fish eggs or larvae that were not alewife or smelt.As a consequence of these findings, the company did not believe that any structural modifications to the intakes were necessary, since any one of the feasible alternatives would have been very costly. The state agencies concurred with these findings.  相似文献   

3.
The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether (BDE-47) sorption onto biochars. A series of biochars prepared underdifferent conditionswere used to test their sorption behaviorswith BDE-47. The extents of sorption behaviorswere parameterized in terms of the single-point adsorption equilibrium constant (Koc ) at three equilibrium concentration (C e ) levels (0.001Sw (solubility), 0.005Sw , and 0.05Sw )whichwasdetermined using the Freundlich model. To elucidate the concentration-dependentdominant mechanisms for BDE-47 sorption onto biochars, K ocwas correlatedwith four major parameters using multiple parameter linear analysis accompaniedwith significance testing. The results indicated that at low concentration (Ce = 0.001Sw ), the surface microporosity term,which represented a pore-filling mechanism, contributed significantly to this relationship,while as concentrationwas increased to higher levels, surface functionality related to surface adsorption began to take thedominant role,whichwas further confirmed by the results of Polanyi-based modeling. Given the above results, adual mode model based on Dubinin-Radushkevich andde Boer-Zwikker equationswas adopted to quantitatively assess the changes of significance of surface adsorption aswell as that of pore fillingwith sorption processdevelopment. In addition, UV spectra of four typical aromatic compoundswhich represented the key structural fragments of biochars before and after interactionswith BDE-47were analyzed todetermine the active functional groups and supply complementary evidence for thedominant interaction force for surface adsorption, based onwhich π-π electron-donor-acceptor interactionwas proposed to contribute greatly to surface adsorption.  相似文献   

4.
Biogas residue (BR) is widely used as a new green fertilizer in agriculture in China. However, it often contains a high concentration of heavy metals so its application should cause our concern. An incubation experiment was conducted to study the risk of pig biogas residue (PBR) and chicken biogas residue (CBR) application on Liuminying soil (LS) and Yixing soil (YS). The soils were incubated for one, three and six months with 0, 2%, 4% and 6% addition of BRs. According to BCR extraction results, the PBR and CBR applications induced an increase in the concentration of exchangeable fraction of Zn. As for the concentration of exchangeable fraction of Cu, an increase was only observed in the treatments with PBR application. The heavy metal binding intensity also showed a similar trend. With the PBR application, for the LS and YS, the highest concentrations of exchangeable Zn increased 3.6 and 9.5 times, respectively, while the exchangeable Cu was increased by 52.6% and 187.1%. Dissolved organic carbon was the limiting factor for the exchangeable Cu while the exchangeable Zn was controlled by soil pH. PBR presented more agricultural risk than CBR when used as fertilizer. Meanwhile, BRs were more adaptable to LS than YS according to the heavy metal release results.  相似文献   

5.
This paper investigates threats to farm management in the northern and central region of Côte d’Ivoire, with a particular focus on climate-related threats. To this end, farmers’ perception and adaptation strategies for climate change have been analyzed. The data were collected from 205 respondents by means of the Focus Groups method, and they were evaluated using a framework analysis. The main reported threats related to the implementation of farming activities are the high cost of inputs and the lack of technical support, which are followed by diseases, insects, and climate variations (scarcity of rains, strong winds, and high temperature). We find that most farmers have a strong perception of changes in climatic conditions. Their perceived impacts on the local environment through evidences like the disappearance of certain farming practices, occurrence of new insects, and the disruption of key time reference periods. Farmers mainly attempt to adapt by adjusting their agricultural calendar, adopting new short-season varieties, and using mixed cropping. We find that the most influential factors for farmers’ adaptation behavior is lack of contact with extension services and the scarcity of rainfall. Our suggestions for future agricultural policies for better adaptation to climate change are to take into account farmers’ perception, to provide suitable climate forecast, and to improve local technical support.  相似文献   

6.
7.
In 1968, excavations in the Climente II cave in the Iron Gates gorge of the River Danube in southwest Romania unearthed the skeleton of an adult male. The burial was assumed to be of Late Pleistocene age because of the presence of Late Upper Palaeolithic (LUP) artefacts in the cave. However, there was no strong supporting stratigraphic evidence, and the body position is reminiscent of Early Neolithic burial practice in the region. Here, we report the results of radiocarbon and stable isotope analyses of the Climente II skeleton, which show that the skeleton dates to the Bølling–Allerød Interstadial ~14,500 cal BP. This is several millennia older than any previously dated human remains from the Iron Gates region and confirms its status as the oldest known burial from Romania. The stable isotope results indicate a diet with an emphasis on aquatic resources, contrary to the commonly held view that the LUP inhabitants of the Iron Gates subsisted mainly by hunting large land mammals.  相似文献   

8.
An appropriate system of laws and regulations and a suitable institutional structure for administration are important requirements for the effective management of small-scale mines. Over the last twenty years, township and village coal mines in China have made a large contribution to the country’s supply of energy. Yet at the same time they have had substantial negative impacts, such as wastage of coal resources, a high casualty rate amongst miners, and a wide range of environmental damage. Two reasons for the magnitude of these externalities are the highly complex nature of the institutional structure for regulating small-scale coal mines, and the excessive and incoherent burden of applicable laws and regulations.  相似文献   

9.
The European Union (EU) has advocated an emission reduction target for developed countries of 80% to 95% below the 1990 level by 2050, and a global reduction target of 50%. Developing countries have resisted the inclusion of these targets in both the UN Framework Convention on Climate Change Copenhagen Accord and Cancún Agreements. This paper analyses what these targets would imply for emission targets, abatement costs and energy consumption of developing countries, taking into account the conditional emission reduction pledges for 2020. An 80% reduction target for developed countries would imply more stringent per capita emission targets for developing countries than developed countries by 2050. Moreover, abatement costs of developing countries would be higher than those of developed countries. An 85% to 90% reduction target for developed countries would result in similar per capita emission targets and abatement costs for developed and developing countries by 2050. Total reduction targets for developing countries would range from 30% to 40% below 2005 levels by 2050 and from 30% to 35% above 2005 levels by 2030. The 2030 target for China would be 40% to 45% above 2005 levels, compared to a target for the EU of 45% to 50% below 1990 and for the United States of America (USA) 30% to 35% below 1990. Emission target trajectories for Brazil, South Africa and China would peak before 2025 and for India by around 2025. From the analysis, we may conclude that from the viewpoint of developing countries either developed countries increase their target above 85%, and/or make substantial side-payments.  相似文献   

10.
Facial and vocal expressions of emotion have been found in a number of social mammal species and are thought to have evolved to aid social communication. There has been much debate about whether such signals are culturally inherited or are truly biologically innate. Evidence for the innateness of such signals can come from cross-cultural studies. Previous studies have identified a vocalisation (the V4 or ‘excitement’ call) associated with high arousal behaviours in a population of killer whales in British Columbia, Canada. In this study, we compared recordings from three different socially and reproductively isolated ecotypes of killer whales, including five vocal clans of one ecotype, each clan having discrete culturally transmitted vocal traditions. The V4 call was found in recordings of each ecotype and each vocal clan. Nine independent observers reproduced our classification of the V4 call from each population with high inter-observer agreement. Our results suggest the V4 call may be universal in Pacific killer whale populations and that transmission of this call is independent of cultural tradition or ecotype. We argue that such universality is more consistent with an innate vocalisation than one acquired through social learning and may be linked to its apparent function of motivational expression.  相似文献   

11.
According to Food and Agriculture Organization and Intergovernmental Panel on Climate Change reports, climate change will lead to a severe food-supply problem. In the future, food production will continually decrease because of aggravated effects of climate change, causing food production to continually decrease. Food production will be unable to satisfy the demand of the global population, leading to a food-security crisis. As the world population continues to increase, the shortage of food will become increasingly severe, particularly for those located in “climate impact hotspots” of tropical, subtropical, small-island countries, and countries that are dependent on imports to meet domestic demand such as Taiwan. Numerous Taiwanese studies have suggested that agricultural and fishery productivity has declined because of climate variation, which may cause changes and instability in food quantity and quality, and increase deficiency and uncertainty in the food supply. Therefore, to discuss the risks posed by climate change to the stability of food supply and demand, this paper, taking Taiwan as a case, explored the impact of climate variation on food security and future adaptation strategies. TaiCCAT’s supportive system for decision-making (TSSDA) was adopted here to assess and analyze the current situations of agricultural and fisheries production and supply, as well as future food supply risks, in addition to evaluating the deficiencies in the existing climate adaptation strategies in order to plan and revise feasible future adaptation alternatives. Based on the rule of risk management, the adaptation strategies recommended in this study were differentiated into two categories: proactive adaptation and planned adaptation. Proactive adaptation is emphasized to counter the uncertainty of food production, which increases the difficulty of production and necessity to import food. Conversely, planned adaptation can be used to manage the uncertainty of food supply to implement adjustments in production and marketing, as well as to mitigate the impact of climate variation.  相似文献   

12.
The in situ application of granular iron (Fe0) has become popular for the destruction of halogenated organic compounds and for the immobilization of specific metals in groundwater. However, a knowledge gap exists concerning the long-term performance of the Fe0-barriers. The corrosion of Fe0 may produce mineral precipitates that alter the system’s hydraulic integrity. For example, data from existing barriers show varying trends in pH, alkalinity, mineral precipitation, and microbial activity. Although the chemical behaviors are site-specific, this paper discusses the concepts involved in developing a generic approach for predicting the trend of aqueous and surface speciation, and the resulting effects on Fe0 treatment systems. Observations from existing Fe barriers are summarized, and the chemical and microbial processes that influence chemical speciation, both in water and on surfaces, are reviewed. A conceptual geochemical model is presented, which illustrates the factors that must be considered in developing a quantitative model that can be used to design monitoring plans for timely detection of clogging in Fe0 reactive barriers. In order to develop quantitative predictive models, field and laboratory research should: (1) assess the extent and rates of media deterioration by analyzing coupled chemical and microbial reactions; and (2) identify the controlling mechanisms for hydraulic alteration within and around Fe0 barriers.  相似文献   

13.
Adaptation to climate change is a major challenge facing the viticulture sector. Temporally, adaptation strategies and policies have to address potential impacts in both the short- and long term, whereas spatially, place-based and context-specific adaptations are essential. To help inform decision-making on climate change adaptation, this study adopted a bottom-up approach to assess local climate vulnerability and winegrowers’ adaptive processes in two regulated wine-producing areas in the Anjou-Saumur wine growing sub-region, France. The data used for this study were collected through individual semi-structured interviews with 30 winegrowers. With a focus on wine quality, climate-related exposure, and sensitivity were dependent on many contextual factors (e.g., northern geographical position, wine regulatory frameworks, local environmental features) interacting with the regional oceanic climate. Climate and other non-climate-related variables brought about important changes in winegrowers’ management practices, varying in time and space. This ongoing process in decision-making enhanced winegrowers’ adaptive responses, which were primarily reactive (e.g., harvesting, winemaking) or anticipatory (e.g., canopy and soil management) to short-term climate conditions. Winegrowers described changing trends in climate- and grapevine (Vitis) -related variables, with the latter attributed to regional climate changes and evolving management practices. Regarding future climate trends, winegrowers’ displayed great uncertainty, placing the most urgent adaptation priority on short-term strategies, while changing grapevine varieties and using irrigation were identified as last resort strategies. The study concluded by discussing the implications of these findings in the context of climate change adaptation in viticulture.  相似文献   

14.
‘Formiguers’ are structures similar to charcoal-kilns that were used to burn piles of biomass with a soil cover in order to produce fertilizers for agricultural plots. Their use was widespread in Spain up to the 1960s and similar structures are still in use in India and Bhutan. Our objective was to study the effects of the ‘formiguer’ on its soil cover in terms of changes in nutrient availability. We built an experimental 0.5-m3 ‘formiguer’ with 68 kg of plant material with a 12% moisture content and 550 kg of soil with a 16% moisture content. The content of organic carbon and mineral nitrogen decreased in the soil cover as a result of burning. After aerobic incubation all samples had a similar content of mineral nitrogen. Exchangeable potassium and total and labile phosphorus increased after burning as a result of the soil cover mixing with the ashes of the biomass as the ‘formiguer’ collapsed during burning in the first two cases, while mineralization of organic compounds produced the increase in labile phosphorus. This input of nutrients for the agricultural plots occurs at a net loss of 0.4–2.5 Mg organic C ha?1. Very small amounts of charcoal were produced and this may be the reason for their low occurrence in soils today. Burning of ‘formiguers’ required the harvest of vegetation from a considerable forest area (10–25 ha per hectare of agricultural land) and represented a significant disturbance of these systems.  相似文献   

15.
乒坛比赛中的“擦边球”,运动员出手不凡,甲运动员打一个球到乙球台擦边而下,乙运动员招架不及,只能望球兴叹,平添几多感叹:感叹甲打了个幸运球,感叹自己无回天之力,球迷则感叹甲打出了令人叫绝的“好球”。 时下,这“擦边球”巳超越乒坛,渗入到了其他一些领域演变成“擦边事”。别的姑且不提,单说经济生活中的某些“擦边事”,诸如:有些人明知公款不能用于吃喝,却把它“擦”上点“伙食结余加菜”的边,美其名“工作餐”,或象征性地收点钱,名正言顺,美酒佳肴,照吃不误,难怪公款吃喝风愈演愈烈,屡禁不止。 厂矿企业界,有的是经济工作的主管部门,有些人也精于此道,变出花样打“擦边球”。国家三申五令,一切新、扩、改建工程,要严格按环保  相似文献   

16.
Hydrogen peroxide is not only an important oxidant in itself;it also serves as both sink and temporary reservoir for other important oxidants including HOx(OH and HO2) radicals and O3 in the atmosphere.Its partitioning between gas and aqueous phases in the atmosphere,usually described by its Henry's law constant(KH),significantly influences its role in atmospheric processes.Large discrepancies between the KH values reported in previous work,however,have created uncertainty for atmospheric modelers.Based on our newly developed online instrumentation,we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of(0.960 ± 0.013) atm(1 atm = 1.01325 × 105 Pa).The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van't Hoff equation form,expressed as lnKH = a/T-b,and a =-ΔH/R,where KH is in M/atm(M is mol/L),T is in degrees Kelvin,R is the ideal gas constant,and ΔH is the standard heat of solution.For acidity dependence,results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level(from pH 7 to pH 1).Combining the dependence of both temperature and acidity,the obtained a and b were 7024 ± 138 and 11.97 ± 0.48,respectively,ΔH was(58.40 ± 1.15) kJ/(K·mol),and the uncertainties represent σ.Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.  相似文献   

17.
According to the classic life history theory, selection for longevity depends on age-dependant extrinsic mortality and fecundity. In social insects, the common life history trade-off between fecundity and longevity appears to be reversed, as the most fecund individual, the queen, often exceeds workers in lifespan several fold. But does fecundity directly affect intrinsic mortality also in social insect workers? And what is the effect of task on worker mortality? Here, we studied how social environment and behavioral caste affect intrinsic mortality of ant workers. We compared worker survival between queenless and queenright Temnothorax longispinosus nests and demonstrate that workers survive longer under the queens’ absence. Temnothorax ant workers fight over reproduction when the queen is absent and dominant workers lay eggs. Worker fertility might therefore increase lifespan, possibly due to a positive physiological link between fecundity and longevity, or better care for fertile workers. In social insects, division of labor among workers is age-dependant with young workers caring for the brood and old ones going out to forage. We therefore expected nurses to survive longer than foragers, which is what we found. Surprisingly, inactive inside workers showed a lower survival than nurses but comparable to that of foragers. The reduced longevity of inactive workers could be due to them being older than the nurses, or due to a positive effect of activity on lifespan. Overall, our study points to behavioral caste-dependent intrinsic mortality rates and a positive association between fertility and longevity not only in queens but also in ant workers.  相似文献   

18.
19.
Mitigation and Adaptation Strategies for Global Change - Considering government and market failure of environmental regulation to combat increasing GHG (greenhouse gas) emissions, green innovation...  相似文献   

20.
In the Kyoto Protocol, industrialised countries have agreed to reduce their carbon dioxide emissions. To achieve that target, direct human induced activities initiated in the Land-use Change and Forestry sector since 1990, shall be included. However, the wording in the Protocol has caused confusion. The IPCC has been requested to deliver a Special Report on Land-use, Land-use Change and Forestry issues arising from this Protocol. In the present study a limited initial assessment of the implications of alternative interpretations of Afforestation, Reforestation and Deforestation (ARD), addition of the soils compartment, the selection of additional activities, and feasibility of monitoring was done for a limited number of countries.The results show that it is possible to keep the biosphere articles in the Protocol even though we had to make several assumptions concerning for example, areas of application and effectiveness of additional activities. The consequences of alternative interpretations for ARD have a large impact on the countries’ assigned amount; varying from a compensation of 26% of total national emissions (Forestry interpretation for Sweden) to an addition of an extra 13% of the emissions (Global interpretation for Australia). Through selection of a large set of additional activities, most of the studied industrialised countries achieve more sequestration than the reduction of emissions they have committed themselves to. Methods for monitoring are available, but there is no one ideal method. Depending on scale and site: a combination of forest inventory with flux measurements and remote sensing is proposed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号