山一村农业生态系统营养物质循环

本文研究了浙江省萧山市山一村农业生态系统中农田、山地和水域３个子系统的氮、磷、钾养分循环。结果表明：该村土壤有机质含量属较高水平，无机氮肥施用量偏大，流失量也较大，磷的总投入量远低于总输出量，钾的输入量也偏低；水体属富营养型，鱼的生长系数仅２．９６。     

MODIS气溶胶光学厚度对城市空气质量的指示

空气污染指数API(Air Pollution Index)是关系大众生产生活的一个重要指标,论证了一种由MODIS(中分辨率成像光谱仪)反演的气溶胶光学厚度产品AOT(Aerosol Optics Thickness)预报空气质量的方法,即依据API的分级标准,将API用特定的步长分组,再把各组的AOT和API均值建立相关模型,并用该模型来预测空气质量指数,经验证,预测值和实际值之间的精度为77.59%,基本达到业务运行的要求。     

The Information Content of a Scalar Plume – A Plume Tracing Perspective

The ability of many animals and insects to track a plume to its source is a particularly impressive feat when the fluid dynamics is considered. Inspired by this observation this research seeks to identify the information in a passive scalar plume suitable for developing robust and efficient plume tracing algorithms. The subject of this study is a scalar plume emanating from a point source in a turbulent boundary layer which has been modeled in a laboratory facility built specifically for this purpose. A coupled PIV-LIF technique is used to measure the velocity and scalar field in a time resolved fashion. This data set is analyzed and the convergence rates of five single-point statistics, suitable as kernels of plume tracing algorithms, are investigated. The experimental data shows that the scalar fluctuations over long downstream distances from the source are characterized by filamentary structures that lead to relatively slow convergence rates for any statistic that is based on mean concentrations. The scalar intermittency, however, converges rapidly toward its true value, in fact converging to a testable hypothesis for source location direction faster than the time scale of the larger scale plume meander.     

产品生命周期评价在固体废弃物管理中的应用

产品生命周期评价应用到固体废弃物的管理 ,可以改变传统的管理方法 ,为固体废弃物管理从产品设计、生产到废弃、处置全过程 ,提供系统的全过程管理概念     

Food (miles) for Thought - Energy Balance for Locally-grown versus Imported Apple Fruit (3 pp)

- This commentary compares the primary energy requirement for apples (cultivar ‘Braeburn’), which were either imported or locally-grown in Meckenheim, Germany. Imported apples of the same cultivar were grown in a Southern hemisphere winter in Nelson, Southland, New Zealand, and were picked at the end of March with subsequent 28 d transport by sea for sale in April in Germany. Locally-grown apples (cultivar ‘Braeburn’) were picked in mid-October and required a primary energy of nearly 6 MJ/kg of fruit including 0.8 MJoule/kg for five months CA storage at 1°C during a Northern hemisphere winter until mid-March. This compared favourably with 7.5 MJoule/kg for overseas shipment from New Zealand, i.e. a ca. 27% greater energy requirement for these imported fruits. Overall, the primary energy requirement of regional produce, stored several months on-site, partially compensated for the larger energy required to import fresh fruit from overseas. This result is in marked contrast to reported overestimates of a reported up to 8-fold energy requirement for domestic versus imported apple juice concentrate [7]. Our own findings of less primary energy required for domestic apple fruit is discussed with respect to providing local employment, fruit orchards preserving the countryside, quality assurance systems for local fruit such as QS and EUREP-GAP, networking and other factors favouring regional production.     

问歇曝气周期对低C/N比污水生物脱氮的影响

研究了间歇曝气生物脱氮工艺中,曝气周期和污水的c/N比对脱氮效率的影响,以及氧化还原电位(ORP)变化规律.中试试验结果表明,TN污泥负荷为0.05 kg/(kg MLVSS.d)时,间歇曝气系统的硝化反应所需曝气时间与总反应时间比至少要在0.5以上,一周期内搅拌时间不宜超过1 h;反硝化过程中难以找到ORP曲线突变点,因此,在低c/N比污水生物脱氮中ORP难以作为工程控制参数;由于原水的碳氮比太低,TN去除率只有35%～40%左右,为提高脱氮效率有必要投入外加碳源.     

Preventive environmental strategies for product systems

The paper describes a model for environmental quality and resource efficiency parameters to be used in evaluation of options for improvement of product systems in a life cycle and system perspective. Four main preventive strategies for product system improvements are described and discussed in the paper. (1) Reformulating user needs and requirements to the system; (2) improvement of product system performance; (3) substitution of the whole product systems or system components on different levels; (4) optimization within and between system units and components. These main strategies are discussed with respect to the structure of the product system (the domain theory), and with respect to efficiency in general. It is concluded that at present, it is not possible to make any definite rank of priorities between the different strategies, but that this should be evaluated when more systematic studies of cases are available.     

Effect of excessive cadmium chloride on the plasmids of E. coli HB101 in vivo

After Escherichia coli HB101 with plasmid pWH58, pWH98, or pTBa₅ were cultered respectively in amp LB broth which contained 50 mg/L CdCl₂ constantly for 24h, these plasmids were isolated from E. coli, and the effect of excessive CdCl₂ on the E. coli HB101 and plasmid DNA was studied by surveying the growth of E. coli HB101 and plasmid, argarose gel electrophoresis and analysis of restriction fragment length polymorphism (RFLP) of plasmids, and plasmid transformation. The results showed that 50 mg/L CdCl₂ treatment lagged the growth of E. coli HB101 for at least 4h, but after grown for 24h there were not significant differences in the growths of E. coli HB101s and the productions of plasmids between the treatment and control. These results implified that E. coli HB101 have induced adaptability to cadmium stress and excessive CdCl₂ did not inhibit the replication and amp + genes expression of plasmid DNA in vivo of E. coli significantly. 50 mg/L CdCl₂ treatment for 24 hours might cause the sequences change of plasmid DNA, but could not lead to the random breakage of plasmid DNA strands. Moreover, after 50 mg/L of CdCl₂ treatment in vivo the transformation activities of plasmid did not altered, implied excessive CdCl₂ could not affect the superhelical structure of plasmid and also not break the loop of plasmid DNA evidently.     

A simple,rapid, and highly informative PCR-based procedure for prenatal diagnosis and carrier screening of phenylketonuria

The polymorphic information content (PIC) and the degree of heterozygosity of several polymorphic systems within the phenylalanine hydroxylase (PAH) gene were determined in 85 European Caucasian and 19 Chinese phenylketonuria (PKU) kindreds. The first system examined, a short tandem repeat (STR), had a PIC of 80 and 73 per cent in these Caucasian and Chinese samples, respectively. The degree of heterozygosity actually observed for this system was 81 and 64 per cent in the Caucasian and Chinese PKU families, respectively. Through the addition of a second polymorphism based on a variable number of tandem repeats (VNTR), the PIC was increased to 90 per cent in Caucasians, but only to 75 per cent in Chinese. The degree of heterozygosity observed for this combination was 94 per cent in European PKU families and 67 per cent in Chinese PKU families. The further addition of an Xmnl RFLP increased both the PIC and the level of heterozygosity in Caucasians to 95 per cent, but did not change either of these measures in Chinese. The combined use of these three polymorphisms significantly increases the informativity of prenatal diagnostic and carrier screening procedures in both Caucasian and Chinese PKU kindreds. Furthermore, since each of these polymorphisms can be studied by PCR-based methods, these new tests can be performed more quickly and easily than previous Southern-based procedures.     

我国热带地区胶-茶-鸡农林复合系统物质循环研究

以海南省文昌市典型的胶-茶-鸡农林复合模式为研究对象 ,以单作胶园、胶茶间作园为对照 ,采用定量研究与定性分析相结合的方法 ,研究其物质循环规律。结果表明 ,胶-茶-鸡农林复合系统的氮、磷输入、输出量最大 ,系统外物质投入率比另两系统明显减少 ,系统内养分循环量增加 ,因此 ,该系统具有较合理的物质循环结构。