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71.
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
72.
长江河口近岸水体自然净化作用及其初步评价 总被引:9,自引:1,他引:8
按照水体的净化机理,结合长江口和上海滨岸带近岸水体的物理、化学和生物等因素的实际特征,对近岸水体的自然净化作用进行了阐述和分析。并在历史资料和实测资料基础上,就近岸水体的自然净化作用进行了评价。评价结果表明,因长江河口近岸水体存在较强的自然净化作用机制,近岸水体体的自然净化能力较强,环境容量较大,但由于污染物输入量的不断增加,部分岸段近岸水体的环境质量有逐渐下降的趋势;近岸水体的自然净化作用具有明显的季节性变化,长江口南岸水域洪水季节水体的自然净化作用比估水季节强,而杭州湾北岸水域的自然净化作用表现为相反的变化趋势,因此建议在近岸污水排放过程中应考虑近岸水体的净化能力,遵循水体的自然净化作用规律。 相似文献
73.
Zhang Jing Feng Zhiming Yang Yanzhao 《中国人口.资源与环境(英文版)》2006,4(2):33-40
The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland" water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention, the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that ①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation. ②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level. ③Irrigation water could meet the crop water demand on Ningxia Plain in 2000, but there was not much space to expand irrigating cultivated land. 相似文献
74.
Changes Of Hydrological Environment And Their Influences On Coastal Wetlands InThe Southern Laizhou Bay, China 总被引:2,自引:0,他引:2
The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore “red tides” happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area. 相似文献
75.
Henrietta Nittby Bengt Widegren Morten Krogh Gustav Grafström Henrik Berlin Gustav Rehn Jacob L. Eberhardt Lars Malmgren Bertil R. R. Persson Leif G. Salford 《The Environmentalist》2008,28(4):458-465
We have earlier shown that radio frequency electromagnetic fields can cause significant leakage of albumin through the blood–brain
barrier of exposed rats as compared to non-exposed rats, and also significant neuronal damage in rat brains several weeks
after a 2 h exposure to a mobile phone, at 915 MHz with a global system for mobile communications (GSM) frequency modulation,
at whole-body specific absorption rate values (SAR) of 200, 20, 2, and 0.2 mW/kg. We have now studied whether 6 h of exposure
to the radiation from a GSM mobile test phone at 1,800 MHz (at a whole-body SAR-value of 13 mW/kg, corresponding to a brain
SAR-value of 30 mW/kg) has an effect upon the gene expression pattern in rat brain cortex and hippocampus—areas where we have
observed albumin leakage from capillaries into neurons and neuronal damage. Microarray analysis of 31,099 rat genes, including
splicing variants, was performed in cortex and hippocampus of 8 Fischer 344 rats, 4 animals exposed to global system for mobile
communications electromagnetic fields for 6 h in an anechoic chamber, one rat at a time, and 4 controls kept as long in the
same anechoic chamber without exposure, also in this case one rat at a time. Gene ontology analysis (using the gene ontology
categories biological processes, molecular functions, and cell components) of the differentially expressed genes of the exposed
animals versus the control group revealed the following highly significant altered gene categories in both cortex and hippocampus:
extracellular region, signal transducer activity, intrinsic to membrane, and integral to membrane. The fact that most of these
categories are connected with membrane functions may have a relation to our earlier observation of albumin transport through
brain capillaries. 相似文献
76.
Whereas past research has treated co-management of common pool resources as if villagers and project implementing authorities
were the only relevant actors, numerous external factors beyond the control of these two partners create barriers to successful
co-management. This paper draws on discussions with Forest Department officials to examine the influence of these forces on
the outcomes of Joint Forest Management (JFM) in Tamil Nadu, India. An empirical inquiry into the operational aspects of JFM
indicates the important roles of political parties, powerful people, and other state institutions and functionaries as well
as the flow of foreign funding. Further, the strong demand by local people for socio-economic development interventions as
opposed to improvement of degraded forests belittles the role of the Forest Department relative to other departments. Numerous
other conditioning factors and relationships are explored. The authors call for reforms in public governance to allow better
participation of all the actors involved for this participatory management approach to succeed and sustain. 相似文献
77.
78.
Although stewardship has been widely defined and used in environmental management and planning, there is a dearth of studies
that describe how the lay public perceives this concept. A national sample of residents in 14 states who live near DOE nuclear
facilities were interviewed to delineate public understanding and awareness of the stewardship program of the U.S. Department
of Energy (DOE). This study discusses the findings of the survey and discusses how institutional trust influences public participation
and resident’s choices of potential stewards. Almost 40% of the respondents could not define stewardship; those who did, believed
that ‘responsibility,’ ‘management,’ and ‘accountability’ are key elements of stewardship. In addition, about a third of the
respondents identified Federal groups and the DOE as potential stewards.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue 相似文献
79.
80.
Matteo Carpentieri Paolo Giambini Andrea Corti 《Environmental Modeling and Assessment》2008,13(3):415-429
Several wind tunnel experiments of tracer dispersion from reduced-scale landfill models are presented in this paper. Different
experimental set-ups, hot-wire anemometry, particle image velocimetry and tracer concentration measurements were used for
the characterisation of flow and dispersion phenomena nearby the models. The main aim of these experiments is to build an
extensive experimental data set useful for model validation purposes. To demonstrate the potentiality of the experimental
data set, a validation exercise on several mathematical models was performed by means of a statistical technique. The experiments
highlighted an increase in pollutant ground level concentrations immediately downwind from the landfill because of induced
turbulence and mean flow deflection. This phenomenon turns out to be predominant for the dispersion process. Tests with a
different set-up showed an important dependence of the dispersion phenomena from the landfill height and highlighted how complex
orographic conditions downwind of the landfill do not affect significantly the dispersion behaviour. Validation exercises
were useful for model calibration, improving code reliability, as well as evaluating performances. The Van Ulden model proved
to give the most encouraging results. 相似文献