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951.
Summary Biosphere reserves are protected areas of representative environments internationally recognised for their value for conservation and for their ability to provide the scientific knowledge, skills and human values to support sustainable development. Biosphere reserves — as a part of the UNESCO programme Man and the Biosphere (MAB) — make up a world-wide network sharing research information on ecosystem conservation, management and development. They include strictly protected core-areas — representative examples of natural or minimally disturbed ecosystems. Core areas are surrounded by buffer zones in which research, environmental education and training and recreation can take place. Buffer zones are, in turn, surrounded by transition areas, large open areas where the aim is to ensure rational development of the natural resources of the region. At present, twelve biosphere reserves are designated in Germany, covering in all an area of 11,589 km2. The role of biosphere reserves to support sustainable development in Germany and Europe is discussed.Karl-Heinz Erdmann is a geographer and Deputy Secretary General at the Secretariat of the German National Committee for the UNESCO Programme on Man and Biosphere (MAB), Federal Agency for Nature Conservation. He is also a Committee Member of the Society for Man and Environment (GMU).  相似文献   
952.
This paper reports the development and application of an analytical method in which both polyethylene glycol ethers or polyethylene glycols are converted into ethylene dibromide via treatment with concentrated hydrobromic acid/glacial acetic acid (1:1) at 150°C for 3 hours. This method can detect <1 ppm of the surfactant in biological tissues, however, the practical utility of the technique is dependent on the solvent and reagent purities and the various cleanup methods which include base hydrolysis, high pressure liquid chromatography and Florisil or acidified Florisil column chromatography.  相似文献   
953.
A simple and rapid method has been optimised to determine glyoxal and methylglyoxal in atmospheric particulate matter by extraction and derivatisation with 2,4-dinitrophenylhydrazine solutions. Minimal sample preparation was required by mixing a portion of filter charged with atmospheric particulate matter with 5?mL of a saturated solution of 2,4-dinitrophenylhydrazine (1.6?g?L?1) in acetonitrile and acidified by H2SO4 (50?µL?L?1). Chromatographic analyses were carried out 1?h after derivatisation solution was mixed. Finally, the proposed method was applied to quantify these dicarbonyls in atmospheric particulate matter samples, which were obtained as part of a large field study to characterise atmospheric aerosol from a rural area of Madrid. Glyoxal concentrations averaged 0.24?ng?m?3, whereas mean values of methyl glyoxal were around 0.95?ng?m?3. Methyl glyoxal levels showed a clear relationship with the particulate matter levels, whereas glyoxal data did not show such a correlation. This could indicate that both dicarbonyls come from different sources.  相似文献   
954.
Nootropic drugs like piracetam, oxiracetam, and nifiracetam are used as memory enhancers. They are thought to directly influence the energetic processes in the brain and produce elevated acetylcholine levels, but they lack protecting therapeutic potentials. Thus, there is a continuing effort directed towards developing a new cognition-enhancing agent, which would be more effective than the currently available drugs, and 2-Naphthyloxy derivatives (PP-20/DPJ) were consequently developed. This in vivo study was designed to compare the memory enhancing potential of PP-20/DPJ with the known nootropic agent, piracetam, in aluminum (Al)-induced neurotoxic model. Results indicated that PP-20/DPJ improved the short-term memory and cognitive behaviors similar to piracetam. Further, both the compounds were equally effective in elevating the acetylcholinesterase and Mg+-ATPase enzyme activity in both the brain regions after Al treatment. Thus the current study suggests, that PP-20/DPJ acts as both a cognition-enhancing agent and as a metabolic enhancer.  相似文献   
955.
Chlorimuron-ethyl, a post-emergent herbicide selectively used in soybean and maize, degrades mainly through chemical hydrolysis. Photolysis has also an important role in the degradation of this compound. Phototransformation of chlorimuron-ethyl takes place through the cleavage of the sulfonylurea bridge, dechlorination, de-esterification and cyclization. Enzymatic de-esterification usually takes place in plant system to liberate the free acid, chlorimuron, which, in fact, inhibits the acetolactate synthase enzyme. In the non-enzymatic environment, de-esterification generally does not occur at normal pH and in moisture-free medium. But on the leaf surface of maize crop de-esterification of chlorimuron-ethyl takes place. The moisture deposited on leaf surfaces by virtue of evapo-transpirational loss of water may cause the de-esterification of chlorimuron-ethyl to the free acid, chlorimuron.  相似文献   
956.
The primary objectives of this research were to estimate the prevalence of anaemia and low haematocrit among preschool children living in Karachi. Through a geographically stratified design, 349 children aged 36–60 months were selected, from five communities in and near Karachi. Blood samples were drawn from children and a questionnaire was administered to evaluate various demographic and socioeconomic characteristics. Chi-square test and multiple logistic regression procedures were used to compare the prevalence of anaemia and low haematocrit among various strata. The overall prevalence of anaemia and low haematocrit were 55.9 and 48.4%, respectively. Children living in the rural community had the highest prevalence of anaemia (78.7%) and low haematocrit (63.8%). Children aged 36–48 months had also higher prevalence of anaemia and low haematocrit. Children's nutritional status was significantly associated with both anaemia and low haematocrit. We recommend appropriate interventions to reduce the burden of these conditions in Pakistan.  相似文献   
957.
A field study was conducted to measure the dislodgeable residues of profenofos applied to jasmine (Jasminum sambac) and risk assessment was done for laborers engaged in picking of flower buds. Profenofos was applied at 0.10, 0.15, and 0.20% concentration and the jasmine bud samples were analysed for residues using GC. The initial deposit of 1.6–3.8, 3.8–7.1, and 5.2–7.6 µg cm?2 was detected on jasmine buds at 0.10, 0.15, and 0.20% concentration, respectively. At the recommended dose of 0.10%, the half-life was 1–2 days and the dislodgeable residues disappeared within 7 days. The results indicate faster disappearance of dislodgeable residues on jasmine buds. Risk assessment was done based on dislodgeable foliar residues and exposure estimates based on surrogate data and expressed as Margin of Exposure (MOE). The entry restrictions for exposure of jasmine flower pickers to profenofos, would be at least, 1 day following application, for the recommended concentration of 0.10% (MOE = 106) and 3 days, at higher concentrations of 0.15% (MOE = 156) and 0.20% (MOE = 115).  相似文献   
958.
In this study, autopsy tissue samples from human liver and kidneys were analysed for Cd, Cu, Pb, Zn, Hg and Mn in 25 subjects (16 males and 9 females) ranging in age from 2 to 70 years. Tissue samples that were pathologically normal were obtained at postmortem and concentrations of metals were determined. In both kidneys and liver, the concentrations of metals followed the order Cd > Hg > Pb > Zn > Mn > Cu irrespective of gender and age group, except in female kidneys where the order was Cd > Pb > Hg > Zn > Mn > Cu. Generally, males had higher concentrations of metals in both the kidneys and liver. Significant correlations of the metals were found in kidney and liver tissues.  相似文献   
959.
During the process of urbanization, people are subject to the indiscriminate use of resources due to competition. The present trend in global population growth predicts that the situation will be aggravated as many people prefer living in towns and cities to resource-poor rural areas. In consequence, limited space, high percentage of ageing population, urban poverty, environmental pollution, changes in urban lifestyles and varied consumption patterns have to be dealt with in sustainable development strategies. In this context, urban agriculture can play a vital role by visualizing the urban homestead as a potentially viable production unit of agriculture. In order to live with limited urban infrastructure facilities, environmental conditions and socio-economic situations, the concept of the Family Business Garden justifies the necessity of its presence through the experience in the Western Province of Sri Lanka. Having a proper mix of environmental and commercial agricultural concerns, the concept paves the way not only to address family food requirements but also to produce for markets under liberalized economies by promoting agro-entrepreneurship and social capital development attempts in urban communities.  相似文献   
960.
This article is an extension and application of Preston and Bedford (1988), especially as relevant to bottomland hardwood (BLH) forests of the southeastern United States. The most important cumulative effects in BLH forests result from incremental forest loss (nibbling) and from synergisms resulting from this nibbling. Present regulatory procedures are ineffective in preventing incremental forest loss because of the focus on permit site evaluation, rather than on large landscapes. Three examples are given to illustrate the need for a landscape focus. This perspective requires preplanning or goal-setting to establish the desired conditions to be maintained in the regulated landscape unit.Spatial and temporal scales are of particular concern for landscape impact assessment. Natural drainage basins of about 106 ha, as identified in U.S. Geological Survey hydrologic units, appear to appropriate spatial units: they have fairly natural boundaries, are of sufficient size to support populations of large, wide-ranging mammals, and are compatible with existing maps and databases. Time scales should be sufficiently long to include recovery of wetland ecosystems from human perturbations. In practice, available data sets limit analysis to no longer than 50 yr. Eight indicators of landscape integrity are identified, based on generally available long-term data sets.Linking technical information concerning cumulativeeffects on landscapes to the evaluation of cumulativeimpacts in regulatory programs (i.e., goal-setting) is a serious issue that can benefit from precedents found in the field of epidemiology, and in the establishment of clean air and clean water standards. We suggest that reference data sets must be developed, relating BLH function to structure (forest area). These can be used to set goals for individual watersheds, based on their present conditions and the magnitude and type of perceived development pressures. Thus the crucial steps in establishing a successful program appear to be (1) establish study unit boundaries, (2) assess the condition of study unit landscape integrity, (3) set goals, and (4) consider the impacts of permit proposals with both goals and the existing condition of the study unit landscape in mind.  相似文献   
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