草原上的体育盛会

正那达慕是中国蒙古族人民具有鲜明民族特色的传统活动,也是蒙古族人民喜爱的一种传统体育活动形式。"那达慕"是蒙古语的译音,不但译为"娱乐、游戏",还可以表示丰收的喜悦之情。每年农历六月初四(多在草绿花红、羊肥马壮的阳历七、八月)开始的那达慕,是草原上一年一度的传统盛会。那达慕在蒙古族人民生活中占有重要的地位,是适应蒙古族人民生活的需要而产生的,有着悠久的历史。     

Modelling air pollution for epidemiologic research--part II: predicting temporal variation through land use regression

Over recent years land use regression (LUR) has become a frequently used method in air pollution exposure studies, as it can model intra-urban variation in pollutant concentrations at a fine spatial scale. However, very few studies have used the LUR methodology to also model the temporal variation in air pollution exposure. The aim of this study is to estimate annual mean NO₂ and PM₁₀ concentrations from 1996 to 2008 for Greater Manchester using land use regression models. The results from these models will be used in the Manchester Asthma and Allergy Study (MAAS) birth cohort to determine health effects of air pollution exposure.The Greater Manchester LUR model for 2005 was recalibrated using interpolated and adjusted NO₂ and PM₁₀ concentrations as dependent variables for 1996-2008. In addition, temporally resolved variables were available for traffic intensity and PM₁₀ emissions. To validate the resulting LUR models, they were applied to the locations of automatic monitoring stations and the estimated concentrations were compared against measured concentrations.The 2005 LUR models were successfully recalibrated, providing individual models for each year from 1996 to 2008. When applied to the monitoring stations the mean prediction error (MPE) for NO₂ concentrations for all stations and years was -0.8 μg/m³ and the root mean squared error (RMSE) was 6.7 μg/m³. For PM₁₀ concentrations the MPE was 0.8 μg/m³ and the RMSE was 3.4 μg/m³.These results indicate that it is possible to model temporal variation in air pollution through LUR with relatively small prediction errors. It is likely that most previous LUR studies did not include temporal variation, because they were based on short term monitoring campaigns and did not have historic pollution data. The advantage of this study is that it uses data from an air dispersion model, which provided concentrations for 2005 and 2010, and therefore allowed extrapolation over a longer time period.     

Effects of low- or medium-pressure ultraviolet lamp irradiation on Microcystis aeruginosa and Anabaena variabilis

A pure culture of Microcystis aeruginosa or Anabaena variabilis, the representatives of water blooming algae, was exposed to low-pressure (LP) or medium-pressure (MP) UV lamps. Irradiated pure culture suspension was subsequently incubated for 7d under white light fluorescent lamps. During incubation, profiles of the number of cells, DNA damage and photosynthetic activity were determined. When UV fluence was 600mJ/cm(2), M. aeruginosa cell numbers decreased throughout the 7-d incubation period, to produce 1.5log reduction (LP) or 1.2log reduction (MP) compared with control. The amount of DNA damage was 2.02x10(-4) ESS/base (LP) and 3.42x10(-4) ESS/base (MP) just after UV irradiation, which became 0.05x10(-4) ESS/base and 0.23x10(-4) ESS/base, respectively, after 3d incubation. However, cell number kept decreasing, even after DNA repair. Photosynthetic activity decreased by 1.5log within 1d (LP) or 3d (MP). Thus, reduction in photosynthetic activity could contribute to the reduction in M. aeruginosa cell numbers. A. variabilis cell numbers reduced by 2.3log (LP) or 2.2log (MP) during the 7-d incubation period; however, after DNA damage repair, cell number began to increase. The amount of DNA damage was 6.07x10(-4) ESS/base (LP) and 4.48x10(-4) ESS/base (MP) just after UV irradiation, which became 0.23x10(-4) ESS/base and 0.40x10(-4) ESS/base, respectively, after 3d incubation. No reduction was observed in photosynthetic activity/cell. Therefore, DNA damage is the main contributor of the reduction in cell number of A. variabilis.     

Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system

The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and sludge stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.     

地质勘探工作的电力供应问题

由于地质勘探队经常在遥远的、难通行的和居民少的地区进行工作,从外部获得电能的可能性不存在.地质人员面临的问题是在勘探地区内生产电能.在这样的条件下,勘探电气装置的供电特点有下列几项.     

建筑防雷参数建模

接地装置包括各种多功能的设备,并且需要满足防止浪涌和电磁兼容性接地的所有安全和操作的要求。为了达到这个标准,电气接地设备（输入电阻、工作时长及触摸和跨步电压等）的操作特性必须同时符合交流（频率为50Hz）和脉冲电流的要求。接地装备的波形参数具备实用和科学的研究价值,例如：波的传播常数和速度、     

干燥方法对沙芥叶片品质的影响

研究自然干燥、真空干燥、鼓风干燥(40、60、80℃)3种干燥方法对沙芥干燥产品及复水后产品物理性质及营养成分的影响。结果表明:不同干燥方法处理的沙芥叶的物理性质及营养成分与鲜叶有较大差异,在物理性质方面,真空干燥叶片复水率显著高于其它处理(p<0.05);在营养成分方面,真空干燥条件下沙芥叶片与其复水后叶片的游离氨基酸、VC、可溶性蛋白含量均高于其它干燥方法。综上所述,真空干燥对沙芥叶片营养成分的破坏最小,复水性好而且干燥时间较短,是一种较好的沙芥叶片干制品的制备方法。      

两种方法提取高原地区人血液DNA效果的比较

进行基因组学的研究,需获取高纯度的基因大分子[1-3],而高原地区由于压力等因素,使得提取试剂受到一定的影响,从而导致提取DNA的浓度、纯度大幅下降,且DNA溶液中各种物质的污染较为严重,原因主要是提取方法、试剂剂量以及溶液配制等方面.通常提取DNA的方法应经济有效,可适用于-20℃以下冷冻的血液样本,同时保证DNA质...