逐级提取试验研究岩石中氟的化学活动性

使用逐级化学提取方法对岩石中氟元素的化学活动性进行了研究.结果表明,不同时代、不同类型岩石中氟的化学活动性具有很大的差异,碳酸盐岩中氟均具有很强的化学活动性,其中氟的可淋失比例一般高于75%;下寒武统黑色岩系中氟的化学活动性与岩石变质程度有关,变质程度较高的黑色碳质板岩中氟的可淋失比例一般小于黑色页岩、黑色硅质岩中氟的可淋失比例.磷块岩中氟的可淋失比例较高,而千枚岩中氟的可淋失比例一般较低;辉绿岩中氟的可淋失比例与原岩中氟含量存在正相关关系.不同时代的石煤中氟的化学活动性具有较大差异.下志留统石煤中氟的可淋失比例(平均为47.39%)一般高于下寒武统石煤中氟的可淋失比例(平均为29.43%).     

磷酸盐对农药草甘膦在不同土壤中迁移的影响

通过饱和土壤与恒定水流速率条件下的土柱混合置换实验,定量分析流出液中草甘膦浓度随时间变化的穿透曲线(BTCs)来预测其在环境中潜在的淋溶损失能力.结果表明,砂土中草甘膦的迁移能力大于红壤水稻土;对红壤水稻土来说,加磷酸盐有增加草甘膦移动性的趋势,砂土中情况刚好相反.因此磷酸盐对草甘膦移动性的影响效果视土壤类型的不同而异.     

杭州市春季大气超细颗粒物粒径谱分布特征

2012年3~5月,采用快速迁移率粒径谱仪(fast mobility particle sizer,FMPS)对杭州市大气超细颗粒物数浓度进行了连续监测和分析研究.结果表明,核模态(5.6~20 nm)、爱根核模态(20~100 nm)、积聚模态(100~560 nm)以及总颗粒物(5.6~560 nm)日均数浓度值分别为0.84×104、1.08×104、0.47×104和2.38×104cm-3.晴天天气下,爱根核模态颗粒物浓度较高,且可观测到核模态和爱根核模态颗粒在早上10:00~11:00开始增加,3~4 h后结束,这说明太阳照射强度促进了新粒子形成.在工作日与周末,人为活动因素使各模态颗粒物浓度分布有明显差异.结合天气因素分析可知,风速和风向也直接影响颗粒物浓度;颗粒物浓度与能见度分析结果表明:杭州地区大气能见度的高低受核模态和爱根核模态的颗粒影响较小,与积聚模态颗粒物浓度呈负相关关系.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

When mobility makes sense: A qualitative and longitudinal study of the daily mobility of the elderly

A majority of North Americans hopes to grow old in the suburbs. This aspiration depends upon their ability to drive and their access to a car. Because it is essential for everyday travel, car-mobility in the suburbs is becoming a symbolic goal. The meanings of mobility for elderly will evolve over time, notably as a result of changes in autonomy. However, the mobility of older adults is mainly understood in terms of daily trips. Little research has considered the temporal dimension of aging as an evolving process. This study aimed at understanding with a qualitative and longitudinal perspective how older people stay (auto-)mobile in their house and their neighborhood against the need to adapt to reduced autonomy and mobility over time. A group of 22 suburbanites aged from 62 to 89 was interviewed in 1999 and in 2006. The results show that even if older people succeed in increasing their mobility, they are headed for inevitable immobility. Among the environmental adaptation strategies that were observed, the constructed behaviors, the dependencies demanding additional supports as well as the social life modulate different evolving experiences of the city: the shrinking city, the fragmented city, and the city by proxy. The built environment is at the heart of a complex process in which the adaptation of mobility contributes to the emergence of new residential experiences.     

显微镜电泳技术研究聚磷氯化铝的混凝特性

采用显微电泳技术和混凝实验研究聚磷氯化铝对100mg/L蒙脱土悬浊水的混凝过程。描述了聚磷氯化铝的电泳特征及其混凝作用特性,并在较低的、相同的碱磷化度B_p（B_p＜1.5）基础上比较聚磷氯化铝与普通聚合氯化铝的混凝特征过程。结果表明,聚磷氯化铝的混凝效能优于聚合氯化铝。     

Parental perception of social risk and of positive potentiality of outdoor autonomy for children: The development of two instruments

An important factor that limits children's autonomy outdoors is parental perception of social danger and traffic danger. To obtain quantitative instruments for these dimensions, this work aimed to explore the validity and reliability of three scales. Two of them describe, respectively, problematic aspects of the area of residence linked to traffic and situations of social degradation that could constitute risk factors for the child's psychological and physical safety (Traffic Danger Perception Scale, Social Danger Perception Scale). The third scale investigates parental perception of the positive potentiality of outdoor autonomy for children's maturation and growth. Interviews were conducted with 377 mothers of children between 8 and 10 years of age residing in six different areas in Italy. The results indicated weak reliability of the Traffic Danger Perception Scale, which requires further investigation, and they confirmed the reliability and the construct validity of the Social Danger Perception Scale and the Perception of Positive Potentiality of Outdoor Autonomy for Children Scale. The perception of social danger was higher in mothers who live in larger urban contexts and who have more personal fear of crime and a lower sense of community. The positive perception of children's autonomy of movement was higher among mothers who live in greener areas, who have a greater sense of community and who have more neighbourhood relations.     

Outbound offending: The journey to crime and crime sprees

Studies on crime and mobility primarily focus on local crime patterns. The city has long played an important role, whether analysing the offence or the offender. This paper goes beyond city boundaries and discusses ‘outbound offenders’, whose crime trips start in a city, but end outside. It is argued that a substantial proportion of crime trips follow this pattern, indicating that areas other than cities also provide interesting opportunities for property crime. We link outbound offending to a number of features that may explain crime travelling, including the target’s features and offender/offence features. We find that outbound offending mostly occurs towards affluent target regions and near motorways, as such confirming findings from previous research. We also find crime sprees to be indicative for mobile offending. Thus, mobile property offenders tend to compensate for travelled distances, not only by targeting affluent areas and using fast transportation means, but also by committing several successive offences, hereby reducing their relative transportation cost for each offence.     

Mobility of arsenic, cadmium and zinc in a multi-element contaminated soil profile assessed by in-situ soil pore water sampling, column leaching and sequential extraction

Three methods for predicting element mobility in soils have been applied to an iron-rich soil, contaminated with arsenic, cadmium and zinc. Soils were collected from 0 to 30 cm, 30 to 70 cm and 70 to 100 cm depths in the field and soil pore water was collected at different depths from an adjacent 100 cm deep trench. Sequential extraction and a column leaching test in the laboratory were compared to element concentrations in pore water sampled directly from the field. Arsenic showed low extractability, low leachability and occurred at low concentrations in pore water samples. Cadmium and zinc were more labile and present in higher concentrations in pore water, increasing with soil depth. Pore water sampling gave the best indication of short term element mobility when field conditions were taken into account, but further extraction and leaching procedures produced a fuller picture of element dynamics, revealing highly labile Cd deep in the soil profile.     

COMPARING THE IMPAIRMENT PROFILES OF OLDER DRIVERS AND NON-DRIVERS: TOWARD THE DEVELOPMENT OF A FITNESS-TO-DRIVE MODEL

The purpose of this research effort was to compare older driver and non-driver functional impairment profiles across some 60 assessment metrics in an initial effort to contribute to the development of fitness-to-drive assessment models. Of the metrics evaluated, 21 showed statistically significant differences, almost all favoring the drivers. Also, it was shown that a logistic regression model comprised of five of the assessment scores could completely and accurately separate the two groups. The results of this study imply that older drivers are far less functionally impaired than non-drivers of similar ages, and that a parsimonious model can accurately assign individuals to either group. With such models, any driver classified or diagnosed as a non-driver would be a strong candidate for further investigation and intervention.