浅谈煤矿透水事故后外排酸性矿井水的治理

采用火焰原子吸收法对大同市“5．18”左云新井煤矿透水事故中所排酸性废水及其应急处理外排水中铁锰进行跟踪测定。结果表明，在废水处理过程中加入石灰石中和，脱铁脱锰，pH均值7．9，总铁浓度均值1．07mg／L，均达到污水综合排放标准。     

Three-dimensional ultrasound in prenatal diagnosis of skeletal dysplasia

A lethal form of bone dysplasia, platylospondylic lethal chondrodysplasia, was diagnosed prenatally using three-dimensional ultrasound. The various types of three-dimensional imaging mode provided diagnostic details not available by conventional two-dimensional ultrasound. The diagnosis was made after referral in the 23rd week of gestation, allowing termination of pregnancy due to the poor prognosis. Prenatal sonograms were compared with postnatal radiographs.     

A quantitative estimation of the effect of prenatal diagnosis in dizygotic twin pregnancies in women of advanced maternal age

Genetic counselling in a dizygotic twin pregnancy is complicated by the large number of possible pregnancy outcomes and by the conceivable differences in the parental valuation of these outcomes. We present the probability distributions of the pregnancy outcomes in dizygotic twin pregnancies for women from 35 to 45 years old without prenatal diagnosis and with transabdominal chorionic villus sampling (TA-CVS) or amniocentesis (AC), using data from the literature. TA-CVS always gives a higher probability of a favourable pregnancy outcome (the birth of one or two infants with a normal karyotype) than AC. For a 35-year-old woman, a 0·7 per cent risk of an unfavourable pregnancy outcome without prenatal diagnosis has to be weighed against the 2·1 per cent excess risk of loss of the entire pregnancy after TA-CVS. For a 45-year-old woman, a 10·2 per cent risk of an unfavourable pregnancy outcome without TA-CVS has to be balanced against a 4·4 per cent excess risk of pregnancy loss after TA-CVS. This study provides a quantitative tool for the support of individual parents with respect to the decision to undergo prenatal diagnosis in a dizygotic twin pregnancy.     

Late-onset isolated cystic hygroma: The obstetrical significance,management, and outcome

We add two cases of prenatally diagnosed late-onset isolated cystic hygroma to the eight cases reported previously in the English literature. The obstetrical significance, management, and outcome of this entity are reviewed. A retrospective study of late-onset isolated cystic hygromas delivered in one medical centre between 1978 and 1992 was made. The medical records of these newborns served as the basis of the present report. A Medline search of the English literature was carried out. Over a period of 15 years, we observed 11 cases of late-onset congenital isolated cystic hygroma, two of whom had prenatal sonographic diagnosis. In one case, a Caesarean section was performed due to a huge lesion. All cases underwent surgical excision with a favourable outcome. Of the eight prenatally diagnosed cases reported previously, one died at birth due to inability to ventilate and two required a tracheostomy. Late-onset isolated cystic hygroma should be differentiated from the early-onset nuchal cystic hygroma. The differential diagnosis is important, as late-onset isolated cystic hygroma does not require any prenatal intervention, but special awareness during labour and Caesarean section in extreme cases. Transport to a perinatal centre with expert neonatal, respiratory, and paediatric surgical care is recommended. The prognosis in general is favourable.     

发生氢气分离离子色谱法间接测定水中硫化物

利用ＫＢＨ４在酸性条件下分解产生的氢气为载气分离水中硫化物，用ＮａＯＨ—Ｈ２Ｏ２溶液吸收Ｈ２Ｓ，并将其氧化为ＳＯ２－４，用离子色谱法测定ＳＯ２－４。方法用于各种水样中硫化物的测定，相对标准偏差为１．５８％，回收率在９０．５％到９８．２％之间。方法适用于水中硫化物的测定     

四川盆地臭氧浓度空间分异及驱动因子研究

为揭示四川盆地臭氧（O₃）的空间分布格局及其驱动因子,通过对2015~2017年四川盆地18城市82个国控环境监测站的O₃浓度观测数据,使用空间自相关,空间热点探测及地理探测器等地统计方法分析研究.结果表明：2015~2017年四川盆地O₃浓度总体呈现上升趋势（由2015年的（79.95±18.82） μg/m³上升到2017年的（88.64±11.67）μg/m³）,污染态势逐年加重.盆地中西部成都,资阳,雅安等城市O₃浓度最高,且高值区范围逐年扩大.O₃浓度的空间分布呈现出显著的聚集性规律（空间正相关,Moran's I指数大于0）,且年聚集区（H-H聚集区或L-L聚集区）主要呈现为H-H聚集区分布在盆地中西部,L-L聚集区分布在盆地东南部.此外,年聚集区的年际变化与浓度变化态势基本一致,即O₃浓度上升（降低）的区域转变为H-H聚集区（L-L聚集区）.基于地理探测器定量分析了二十个社会经济及自然驱动因子对O₃浓度空间分异的影响,结果显示社会经济因子占主导作用,其中城建用地占区面积比重（驱动值,q=0.5734）,人口密度（q=0.5479）的驱动作用最为突出,自然因子中年降水量（q=0.4592）具有最显著的驱动作用;地理探测器双因子交互对O₃浓度空间分异的影响有明显的交互增强作用（每个单因子q值平均增大了1.5~2.1倍）,且交互均值（即各因子交互q值的均值）与最大交互值逐年增大.在使得交互值达到最大驱动值的双因子中,出现频率最高的是人口密度（7次）和工业烟粉尘排放量（7次）.     

Nontargeted identification of peptides and disinfection byproducts in water

A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts(DBPs).Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs.Peptides are thought to be an important category of DBP precursors in water.However,little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations.To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water,we developed a novel high throughput analysis strategy,which integrated multiple solid phase extraction(SPE),high performance liquid chromatography(HPLC)separation,and non-target identification using precursor ion exclusion(PIE)high resolution mass spectrometry(MS).After MS analysis,structures of candidate compounds,particularly peptides,were obtained by searching against the Human Metabolome Database(HMDB).Using this strategy,we successfully detected 625 peptides(out of 17,205 putative compounds)and 617 peptides(out of 13,297)respectively in source and finished water samples.The source and finished water samples had 501 peptides and amino acids in common.The remaining 116 peptides and amino acids were unique to the finished water.From a subset of 30 putative compounds for which standards were available,25 were confirmed using HPLC-MS analysis.By analyzing the peptides identified in source and finished water,we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs.     

云南菊科入侵物种与本地共生物种光合特性比较

为了探求菊科入侵植物的入侵机制,了解菊科入侵植物与非入侵植物光合特性的差异,以云南省包括薇甘菊(Mikania micrantha)、紫茎泽兰(Ageratina adenophora)、飞机草(Chromolaena odorata)、三叶鬼针草(Bidens pilosa)在内的4种菊科入侵物种为研究对象,并以与其共生的菊科外来非入侵物种熊耳草(Ageratum houstonianum)为对照,研究外来入侵物种与非入侵物种叶片特性及气体交换参数等方面的区别. 结果表明:薇甘菊、紫茎泽兰、飞机草和三叶鬼针草的P_nmax(maximum net photosynthetic rate, 最大净光合速率)分别为15.92、18.69、17.15和22.78 μmol/(m2·s),分别比其共生非入侵物种熊耳草的高出21.63%、42.77%、31.02%和73.99%;4种入侵物种的LSP(light saturation point, 光饱和点)和LCP(light compensation point, 光补偿点)也显著高于熊耳草,但其AQY(apparent quantum yield, 表观量子效率)却显著低于该共生种. 4种入侵物种叶片的N_mass(leaf N content per unit mass, 单位质量N含量)和CC_mass(leaf construction cost per unit mass, 单位质量建成成本)均显著高于熊耳草,除飞机草外,其他3种入侵物种的PEUE(photosynthetic energy use efficiency, 光合能量利用效率)和PNUE(photosynthetic nitrogen use efficiency, 光合氮利用效率)均显著高于熊耳草,而飞机草和熊耳草之间差异并不显著. 5种植物叶片N_mass分别与叶片SLA(specific leaf area,比叶面积)、CC_mass呈极显著正相关,与植物P_nmax、叶片P_mass(leaf N content per unit mass, 单位质量P含量)和PEUE呈显著正相关,植物P_nmax与PNUE、PEUE呈极显著正相关,与叶片SLA呈显著正相关. 研究显示,与菊科共生外来非入侵植物相比,较高的光合特性参数、叶片特性指标和能量利用效率指标可能是外来菊科入侵物种成功入侵的原因之一.      

京津冀PM2.5时空分布特征及其污染风险因素

为分析京津冀及其周边区域2013年典型污染事件中PM_2.5的时空分布特征及污染风险因素,根据国家城市环境空气质量实时发布数据和京津冀地区地理国情信息监测成果,采用空间数据挖掘方法对PM_2.5污染的热点区域进行了划分;并采用地理探测器定量分析了PM_2.5污染风险因子及其影响程度. 结果表明:在选取的京津冀6个城市中,在PM_2.5污染事件统计上存在保定—廊坊—北京—天津—承德—张家口的污染顺序. PM_2.5污染在空间上呈河南省(山东省)—河北省—北京市(天津市)一线的带状分布特征,在单次污染事件中,城市间的PM_2.5污染存在空间运移关系. 空间热点探测表明,京津冀及其周边区域主要分为5个热点聚集区,其中3个高值区分布在北京市、天津市、河北省和山东省的中部,面积分别为5.31×104、10.26×104、5.04×104 km2. 在8个污染风险因子中,污染企业总数(影响力为0.97,下同)、降水量(0.93)、地形坡度(0.89)对PM_2.5污染的影响显著高于其他风险因子;其他风险因子影响力排序依次为人口数量(0.60)、降水量大于0.1 mm的降水日数(0.57)、地表覆盖类型(0.52)、年均相对湿度(0.51)、年均风速(0.33),但风险因子间相比没有显著性差异. 研究显示,京津冀地区PM_2.5污染的主要因素是污染物排放,其次,气象要素中的年降水量和自然地理环境中的地形坡度也是影响PM_2.5污染特征的重要风险因子.      

Effects of multitasking on operator performance using computational and auditory tasks

This study investigated the effects of multiple cognitive tasks on human performance. Twenty-four students at North Carolina A&;T State University participated in the study. The primary task was auditory signal change perception and the secondary task was a computational task. Results showed that participants' performance in a single task was statistically significantly different from their performance in combined tasks: (a) algebra problems (algebra problem primary and auditory perception secondary); (b) auditory perception tasks (auditory perception primary and algebra problems secondary); and (c) mean false-alarm score in auditory perception (auditory detection primary and algebra problems secondary). Using signal detection theory (SDT), participants' performance measured in terms of sensitivity was calculated as ?0.54 for combined tasks (algebra problems the primary task) and ?0.53 auditory perceptions the primary task. During auditory perception tasks alone, SDT was found to be 2.51. Performance was 83% in a single task compared to 17% when combined tasks.