749 resultados para 2004-07-BS


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本文从城市生态系统的结构、功能和协调度三个方面构建了生态城市的指标体系,提出了生态城市的评价方法,并选取沿海16个城市进行城市生态化建设的综合评价与比较分析。采用适合生态城市建设的数学模型对这些城市的复合生态系统进行定量分析,其中指标涉及人口指标、生态环境指标、经济指标与社会指标4个方面,构建3个一级指标,10个二级指标,25个三级指标。得出了16个沿海城市生态化水平的比较结果,因之深圳在城市结构、城市功能方面明显高于其它城市,其生态化综合水平位居首位,其值超过标准值达到了1.19,营口市在工业废水达标率、环境噪声达标率、人均生活用水、人均国民生产总值与失业率方面得分最低是导致其生态化综合水平最低的主要原因。16市在城市环境方面得分普遍较低,表明大气质量与环境噪声是限制这些城市生态建设的主要因素。

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对农田污灌区污水和土壤监测结果表明 ,土壤中Cd、As、Hg、Cu、Pb、Cr和Zn等含量为当地环境背景值的1 5 5~ 5 2 9倍 ,其中Cd和As含量分别为国家土壤环境质量 2级标准的 3倍和 1 4 2倍。污水中 7种重金属含量为农田灌溉水质标准的 4 8~ 34倍 ,部分有机污染物含量为灌溉水质标准的 1 1 0~ 1 87倍。以 3级标准为最大容量限值 ,土壤重金属达土壤环境容量的污灌年限估算结果依次为Cr>Hg >Pb >Cu >Zn >Cd。污土清灌和污水直接灌溉均影响盆栽水稻的正常生长 ,其中污染土壤持续污灌可导致部分秧苗死亡

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一种醇类燃料燃烧脱除偏二甲肼废气的方法及设备,以燃料醇为燃料,点燃该燃烧器,通入体积百分比浓度为1-30%的偏二甲肼废气一同燃烧,生成水和二氧化碳和氮气,达到处理偏二甲肼废气的目的。焚烧炉结构简单,炉膛内装有废气分布环,能使废气充分燃烧,尾气经检测,无残留的偏二甲肼尾气排放达到国家规定的排放标准。

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一种燃料燃烧处理偏二甲肼废气的方法及设备,以燃料油为燃料,点燃该燃烧器,通入体积百分比浓度为1-30%的偏二甲肼废气一同燃烧,生成水和二氧化碳和氮气,达到处理偏二甲肼废气的目的。焚烧炉炉膛内装有废气分布环,能使废气充分燃烧,尾气经检测,无残留的偏二甲肼,排放达到国家规定的排放标准。

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Carbon isotopes of individual lipids in typical organisms from the Nansha sea area were measured by the GC-IRMS analytical technique. delta(13)C values of saturated fatty acids in different organisms examined are from -25.6parts per thousand to -29.7parts per thousand with the average values ranging from -26.4parts per thousand to -28.2parts per thousand and the variance range of 11.8parts per thousand, between different organisms is also observed. Unsaturated fatty acids have heavy carbon isotopic compositions and the mean differences of 2.9%.9-6.8parts per thousand compared to the same carbon number saturated fatty acids. delta(13)C values of n-alkanes range from -27.5%o to -29.7parts per thousand and their mean values, ranging from -28.6parts per thousand, to -28.9parts per thousand, are very close in different organisms. The mean difference in delta(13)C between the saturated fatty acids and n-alkanes is only 1.5parts per thousand, indicating that they have similar biosynthetic pathways. The carbon isotopic variations between the different carbon-number lipids are mostly within +/-2.0parts per thousand, reflecting that they experienced a biosynthetic process of the carbon chain elongation. At the same time, the carbon isotopic genetic relationships between the biological and sedimentary lipids are established by comparative studies of carbon isotopic compositions of individual lipids in organisms and sediments from the Nansha sea area, which provides scientific basis for carbon isotopic applied research of individual lipids.

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The distribution, feeding and oxygen consumption of Calanus sinicus were studied in August 2001 on a transect across Yellow Sea Cold Bottom Waters (YSCBW) and two additional transects nearby. The distribution of C. sinicus adults and copepodites stage CV appeared to be well correlated with water temperature. They tended to concentrate in the YSCBW (>10,000 ind. m(-2)) to avoid high surface temperature. Gut pigment contents varied from 0.44 to 2.53 ng chlorophyll a equivalents (chl a equiv.) ind.(-1) for adults, and from 0.24 to 2.24 ng chl a equiv. ind.(-1) for CV copepodites. We found no relationship between gut pigment contents and the ambient chl a concentrations. Although the gut evacuation rate constants are consistent with those measured for other copepods, their low gut pigment contents meant an estimated daily herbivorous ingestion of <3% of body carbon in the YSCBW and <10% outside the YSCBW. However, based on estimates of clearance rates, C. sinicus feeds actively whether in the YSCBW or not, so the low ingestion rates probably reflect shortage of food. Oxygen consumption rates of C. sinicus ranged from 0.21 to 0.84 mul O-2 ind.(-1) h(-1), with high rates often associated with high temperature. From the oxygen consumption rates, daily loss of body carbon was estimated to be 4.0-13.7%, which exceeds our estimates of their carbon ingestion rates. C. sinicus was probably not in diapause, either within or outside the YSCBW, but this cold-water layer provides C. sinicus with a refuge to live through the hot, low-food summer.

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lambda-Carrageenan is a sulfated galactan isolated from some red algae and have been reported to have many kinds of biological activities. lambda-Carrageenan from Chondrus ocellatus, an important economic alga in China and many other parts of the world, was degraded by microwave, and obtained five products that have different molecular weight: 650, 240, 140, 15, 9.3 kDa. Analytical results confirmed that microwave degradation might not change the chemical components and structure of polysaccharides under certain condition. In this study, tumor-inhibiting activities, weight of immune organ, nature killer cells activity, lymphocyte proliferation ratio and pathological slice of spleen and tumor cells from the control group and lambda-carrageenan-treated mice of transplanted S 180 and H22 tumor were investigated. The results indicated that the five lambda-carrageenan samples all showed antitumor and immunomodulation activities in different degree. Molecular weight of polysaccharides had notable effect on the activities. In addition, their antitumor and immunomodulation have some relevance and the five lambda-carrageenans probably inhibited tumor by means of activating the immunocompetence of the body. Among all the experiment results, samples with the highest activities are PC4 and PC5 whose molecular weight are 15 and 9.3 kDa. (C) 2003 Elsevier Ltd. All rights reserved.

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喀斯特石漠化是土地荒漠化的主要类型之一。 喀斯特生态系统的脆弱性决定了喀斯特生态系统的易损性和退化喀斯特生态系统的难恢复性,但它与发生石漠化并没必然的联系,喀斯特石漠化是岩溶生态系统退化的结果,而不是喀斯特生态系统脆弱性的必然表现。故所指的喀斯特石漠化,特指人为加速的石漠化,属于人为荒漠化的一种类型,但强调喀斯特石漠化的人为成因性,并不是否定自然背景对喀斯特生态系统的制约作用。石漠化土地的分类既要能反映出石漠化发生的严重程度,也要能体现石漠化土地的成因和岩性地貌等地质背景对生态学过程的影响,因此,作者提出以“土地利用类型+植被+岩性+地貌+石漠化程度”对人为加速石漠化过程中石漠化土地进行类型划分,以正确评价石漠化土地的生态环境价值。

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岩溶石漠化退化土地是目前西南岩溶地区经济发展、生态恢复与重建工作中严重的问题之一。由于岩溶生态系统的独特性和脆弱性, 岩溶生态系统土壤具有不同于其它生态脆弱区土壤的特征, 本文将其归纳为成土速率决定的在人类活动尺度下土壤不可再生性即脆弱性、土壤侵蚀(土层丢失) 的独特性、土壤退化过程中空间分布的斑块化及其与岩性的相关性、土壤退化过程中有机碳活性成分下降和来源变化、土壤退化导致岩溶生态系统生态过程中断。因此, 在退化岩溶生态系统的研究中, 要加强对岩溶生态系统土壤特性及退化恢复理论的研究。

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为了解喀斯特地区景观变化过程及相应的生态效应,利用遥感影像数据对黔中地区1995 —2000 年的景观格局与动态进行分析。结果显示:研究区以灌木林地、坡耕地、中覆盖度荒草地占据着景观中的优势地位。旱地、林地和荒草坡的转换关系复杂,退耕还林还草与毁林毁草开荒同时并存,植被恢复与退化并存,整体景观尚处于一种波动状态,区域土地利用生态价值并未有明显提高,而呈下降趋势。研究区景观格局特征是岩性、地貌和人为活动共同作用的结果,景观斑块的转化主要受人文因素的影响,耕地的变化主要是被建设用地占用。在1995 —2000 年的土地利用变化中,研究区的生态既有恢复,又存在继续恶化的趋势。

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生态系统的脆弱性评价对于生态系统管理具有重要作用。在分析岩溶生态系统脆弱性特征和影响因素的基础上,构建了针对岩溶自然系统的脆弱性评价指标体系,涵盖了岩溶生态系统的结构脆弱性、生态过程脆弱性、生态功能脆弱性和人为胁迫脆弱性4个方面,评价指标分别是结构稳定性、多样性生境、能量利用和积累、直接使用价值、石漠化程度和速率等。以不同类型的原生岩溶生态系统的生态基准值作为比较基础,评价系统将现有的退化岩溶生态系统的脆弱性划分为轻微脆弱、中度脆弱、重度脆弱以及系统崩溃4级

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Previous studies have witnessed some psychological or behavioral deviation (such as aggressive behavior) might have an association with cerebral hemisphere cooperative dysfunction, however, it is still unclear whether there is an association between individuals with social cognitive bias and their hemispheric cooperative functions especially while the interhemisphere cooperative processing is under the conditions of emotional interferences. The purpose of this study is to explore the differences between the social cognitive bias group and the normal group’s interhemispheric cooperative functional activity under the conditions of with or without interferences. Methods: According to Dodge’s (1993) model of “social-cognitive mechanisms in the development of conduct disorder and depression”, a 51 items of “social cognitive bias scale” was created and was used to screen the high score group. 20 male subjects was composed of high score group and other 23 matched the control group. Stimulus tachistoscopically presented to the bilateral visual field and compared with the central. Both group’s interhemispheric cooperative functional activity were observed and compared under the conditions of without interference- i.e. base level and with the emotional interferences of white noise level and negative evaluative feedback speech level while finishing: experiment one: Chinese word-figure Stroop analogue task; experiment two: two single Chinese Characters combination task. Heart rate and respiratory rate were simultaneously recorded as index of emotional changes. Results: ① The high score group showed a decrease in processing accuracy compared with the normal group under the condition of white noise interference level in experiment one. ② Still under the condition of white noise interference level, there were more reaction time and more errors were observed in high score group than normal in experiment two. ③ Both groups showed speed up effect and the strategic processing tendency of speed-accuracy trade-off effect under the condition of white noise interference level in both experiments. ④ Between group differences of interhemipheric cooperative function were not observed under the conditions of base level and the negative evaluative feedback speech level within both experiments. Conclusion: The results suggested that interhemispheric cooperative functional differences exists between the two groups, characterized as ① differences existed in interhemispheric cooperative processing strategy between the two groups, with the high score group presented “hierarchic” deficiency strategy. ② the appearance of the differences between the two groups were condition specified , and in this research it was only under the white noise interference condition. ③ the features of the differences between the two groups were the differences on multidimensional performances and with a deficit orientation in high score group. ④ the varieties of the differences were changing with cooperative tasks, as in this research the high score group performed worse in complementary cooperative task. In addition, both group adjusted the processing strategy respectively under the condition of white noise evoked emotional interference implied that the interaction between the interhemisphere cooperative processing and emotion might exist.

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2002

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Este trabalho divulga a base de dados espaciais, elaborada para o Município de Campinas, onde foram utilizadas técnicas de geoprocessamento. O município foi mapeado e classificados os usos e cobertura das terras, com ênfase para os remanescentes de vegetação natural e as áreas urbanizadas ou em urbanização.