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1.
S. N. Goroshkevich 《Russian Journal of Ecology》2008,39(3):168-175
A statistical analysis of interannual variation in a set of vegetative and generative characters over 13 years has been performed to characterize the growth and seed production dynamics of the Siberian stone pine (Pinus sibirica Du Tour) in the southeast of the forest zone in western Siberia. The results have shown that the range of fluctuations in most of vegetative characters is ordinary and their distribution is close to normal. The range of fluctuations in many generative characters is enormous (from 0 to +∞), and the distribution of their values is usually skewed, with low values being recorded several times more frequently than high values. Most variable are the proportion of abortive cones and other characters that are determined mainly in the spring of the pollination year. These characters account for a very high level of variation in the total seed production. 相似文献
2.
测试了两种消石灰与垃圾焚烧烟气中HCl的反应率,得出了消石灰的反应率与反应时间的反应曲线,分析了消石灰与HCl的反应机理及影响消石灰最终反应率的因素。试验结果表明,消石灰与HCl反应初期按灰层扩散控制进行,两种消石灰的最终反应率分别为16%和36%。 相似文献
3.
张似松 《长江流域资源与环境》1993,2(2):155-159
分析江汉平原粮食生产的优势与问题,运用商品经济的观念,提出改革开放新形势下加快江汉平原粮食开发的设想,即依托市场,按照价值规律,科学地调整种植业比例和粮食种类结构,发展优质品种,扩大优化模式及采用高新技术等,通过优质、高产、高效,促进江汉平原粮食生产的发展。 相似文献
4.
5.
Geochemical characteristics of surficial sediments in the Panangad region of Cochin estuary, the largest brackish-water humid ecosystem in the south-west coast of India, were analysed. Temporal variations in nutrient stoichiometry, seasonal characteristics of redox elements Fe and S, and the phosphorus geochemistry were employed for the purpose. The stoichiometric analysis pointed towards autochthonous origin of organic matter, possibility of nitrogen limitation, and allochthonous modification of redox conditions. Seasonal variations were not statistically significant for all the geochemical parameters, whereas significant spatial variations were observed with lower values at sandy stations, suggesting that the texture of the sediments is the main factor influencing the sediment geochemistry. Significant inter-relations between the geochemical parameters also suggest a common control mechanism. Based on these geochemical characteristics, the study region can be effectively categorized into two distinct zones, viz. (1) erosion and transportation and (2) deposition zones. 相似文献
6.
Ricardo Braun 《Environment, Development and Sustainability》2007,9(4):387-411
The implementation of sustainable development may seem a simple concept when written on paper. However to carry-out long term
actions put forward by the Agenda 21 (AG21) at the local level represents one of the main challenges as municipal governments
in general do not have the capacity to effectively implement the process.
Regional environmental assessment (REA) has shown to be effective in supporting decision-making not only to correct environmental
problems due to past unsustainable social-economic developments but also help local governments to implement sustainable actions.
However this requires long-term investments of AG21 plans and projects. The allocation of regular and consistent financial
resources is one of the main ingredients for the sustainable development process. But traditional plans and projects financed
by national and/or international funds may not be sustainable in the long-term because they become dependent on external funding.
Research demonstrate that innovative economic instruments such as ecotaxes represent a feasible alternative to sponsor local
sustainability because taxes are collected permanently by the government and could be invested in continuous actions. Ecotaxes
experiences have provided important reference to structure a municipal incentive model (MIM) to sponsor AG21’s environmental
plans and projects on a long-term (permanent) basis.
However sustainable development cannot be solely through economic investments. A comprehensive municipal environmental management
scheme (MEMS) has been established to support the incentive model. The scheme seeks not only to improve local institutional
framework but also incentive continuous participation of local stakeholders at all levels of society. Participatory events
and the provision of incentives (educational and financial) are key to motivate society to protect the environment and support
actively the sustainable development process as emphasised in the RIO-92 Conference. 相似文献
7.
区域排污权交易模型研究 总被引:9,自引:0,他引:9
本文在分析了排污权交易研究进展的基础上,指出区域污染权交易比传统的排污权交易意义更大,并提出排污权交易地区交叉补贴的设想:将发达地区的排污权交易所得向欠发达地区转移,以解决欠发达地区产业结构调整乏力以及对发达地区的二次污染和发达地区环境容量资源短缺问题。在不考虑交易成本的假设下,通过建立不同地区排污权交易模型以确定排污权交易总量及其交易价格以及交易所获净增纯收益等。太湖流域由于经济最为发达,环境问题十分突出,是目前我国最适宜率先进行区域排污权交易试点的地区。通过假定太湖流域无锡和常州两市进行排污权交易,并利用两市1991—2000年的环境统计资料等相关资料进行了验证。计算结果表明区域排污权交易不仅具有明显的经济和环境效益,而且也是协调环境区域矛盾的重要手段。因此,不同地区间进行排污权交易在我国具有重要意义,在太湖流域等经济发达地区收效尤其明显。 相似文献
8.
M. Marcelli M. Caburazzi A. Perilli V. Piermattei E. Fresi 《Chemistry and Ecology》2005,21(5):351-367
The towed undulating vehicle (TUV), named SARAGO, was used for two fine-scale surveys between the Italian and the Sardinian coasts during the Astraea 2 cruise (6-7 and 26-27 September 1995), studying the deep chlorophyll maximum distribution. SARAGO sections identify a sub-surface doming with higher chlorophyll a and primary production concentrations in the upwelling area of a cyclonic gyre region, detected by sea-surface temperature images. In the first section, the cyclone presents a double doming, in density and salinity, with shallower and concentrated patches of chlorophyll a for about 2 miles. Twenty days later, the second section shows that the gyre changes shape and extension, showing a single doming with higher primary production and chlorophyll a concentrations, distributed over a large area of about 40 nautical miles. SARAGO allows analysis of this high-variability phenomenon (cyclonic gyre) and allows concentrated patches (2 nm) to be identified, thus proving the importance of TUVs in the study of mesoscale processes. 相似文献
9.
The evolution of sustainability 总被引:1,自引:0,他引:1
Six separate but related strains of thought have emerged prominently since 1950 in discussions of such phenomena as the interrelationships among rates of population growth, resource use, and pressure on the environment. They are the ecological/carrying capacity root, the resources/environment root, the biosphere root, the critique of technology root, the no growth/slow growth root, and the ecodevelopment root.Each of these strains of thought was fully developed before the word sustainable itself was used. Many of the roots are based on fundamentally opposing assessments of the future of mankind. Many of the roots, such as the ecology/carrying capacity root, are based on physical concepts, and they exclude normative values. Others, such as the ecodevelopment root, include such values as equity, broad participation in governance, and decentralized government.When the word sustainability was first used in 1972 in the context of man's future, in a British book,Blueprint for Survival, normative concepts were prominent. This continued to be the case when the word was first used in 1974 in the United States to justify a no growth economy.Sustainability was first used in a United Nations document in 1978. Normative concepts, encapsulated in the term ecodevelopment, were prominent in the United Nations publications.After about 1978, the term sustainability began to be used not only in technological articles and reports but also in policy documents culminating in the use of the term in the report of the summit meeting of the Group of Seven in 1989.The roots of the term sustainability are so deeply embedded in fundamentally different concepts, each of which has valid claims to validity, that a search for a single definition seems futile. The existence of multiple meaning is tolerable if each analyst describes clearly what he means by sustainability. 相似文献
10.
采集太原市城北和城南区域环境空气和5类污染源挥发性有机物样品,测定样品中典型单环芳烃稳定氢同位素(δD)组成,基于同位素质量平衡原理计算单环芳烃从源到环境空气受体的δD初始混合值,探讨单环芳烃来源.结果表明,柴油挥发源、溶剂挥发源、汽油挥发源(97#)、汽油挥发源(95#)、机动车尾气(97#)、机动车尾气(95#)和民用燃煤源中单环芳烃δD范围依次为:(-138.7‰~-115.5‰)、(-147.0‰~-121.0‰)、(-150.8‰~-117.6‰)、(-131.8‰~-113.8‰)、(-171.2‰~-120.0‰)、(-138.9‰~-102.7‰)和(-168.3‰~-142.3‰),民用燃煤源中单环芳烃δD显著贫重氢同位素(D)组成,机动车尾气源与汽油挥发源中苯的δD相比显著贫D,可用于探索污染物转化过程;城北和城南环境空气中δD范围为(-131.7‰~-115.1‰)和(-131.9‰~-74.9‰),δD初始混合值为-138.4‰和-173.9‰,体现了其来源差异. 相似文献