常德市土壤水分平衡指标定量计算研究

土壤水分平衡指标是衡量某一区域土壤水分状况的重要标志，正确掌握某一区域的土壤水分平衡指标．有利于该区农业生产的合理布局和各种农作物的合理配置。定量计算表明：常德市的几种主要土壤水分平衡指标为：年可能蒸散量Ep919mm，年实际蒸散量E．906mm，土壤年缺水量D13mm，土壤年余水量R473mm。通过对常德市全年土壤水分收支情况的分析，得到了较为满意的结果，为有关方面提供了借鉴材料。     

Spatial variation in soil inorganic nitrogen across an arid urban ecosystem

We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO₃-N and NH₄-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO₃-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH₄-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO₃-N and NH₄-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO₃-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.     

悬浮液进样石墨炉原子吸收光谱法测定土壤样品中微量硒

采用悬浮液进样石墨炉原子吸收光谱法测定土壤样品中微量硒，选用钯－抗坏血酸为基体改进剂、锆涂覆石墨管。以标准物质制作校正曲线等一系列措施，有效消防共存元素的干扰，并保证了标准系列与土壤样品的原子化条件的一致性，获得了满意的分析结果。     

ATSDR Science Panel on the Bioavailability of Mercury in Soils: Lessons Learned

On the basis of discussion and analysis during and following an ATSDR science panel on the bioavailability of mercury in soils, it is apparent that the default assumption of 100% relative bioavailability for mercury-contaminated soils is excessively conservative. However, current knowledge does not allow the development of default assumptions or guidelines for determining relative bioavailability of mercury in soils. Until such default assumptions or guidelines can be developed, site-specific assays of bioavailability, preferably using either animal bioassays or validated in vitro techniques, may provide the best approach for estimating soil-mercury bioavailability.     

Smoking during pregnancy,stigma and secrets: Visual methods exploration in the UK

BackgroundMoral judgements are commonly directed towards mothers through reference to health behaviour in pregnancy, and working-class mothers are particularly subject to this moral gaze.AimTo gain an in-depth understanding of the health issues affecting 10 low income pregnant women from deprived areas of south Wales, UK.MethodsParticipants completed visual activities (timelines, collaging or thought bubbles and dyad sandboxing) prior to each interview. Participants’ visual representations were used in place of a topic guide, to direct the interview. Guided by feminist principles, 28 interviews were completed with 10 women. Data were analysed thematically.FindingsSmoking was discussed at length during interviews, and this paper focuses on this issue alone. Five of the participants had smoked during pregnancy. Negative reactions were directed towards pregnant women who smoked in public, resulting in maternal smoking being undertaken in private. Participants also reported awkward relationships with midwives and other health professionals, including receipt of public health advice in a judgemental tone.DiscussionSmoking during pregnancy is a particularly demonised and stigmatised activity. This stigma is not always related to the level of risk to the foetus, and instead can be seen as a moral judgement about women. We urgently need to move from individualised neo-liberal discourses about the failure of individual smokers, to a more socio-ecological view which avoids victim blaming.ConclusionStigma from friends, family, strangers and health professionals may lead to hidden smoking. This is a barrier to women obtaining evidence based stop smoking support.     

氮肥施用对冬小麦土壤残留NO3^——N含量及根系分布影响

通过6个氮水平试验，研究了不同氮肥用量对冬小麦土壤剖面NO3^--N含量及其与根系空间分布对应关系的影响；探索了土壤剖面NO3^--N含量与氮肥施用量的趋势规律，以及冬小麦施用氮肥对地下水造成污染的成因、规律及最危险时期。     

链霉菌查尔酮合成酶基因克隆及原核表达载体构建

根据Genbank数据库已知的链霉菌的查尔酮合成酶基因的保守区设计chs基因特异简并引物,土壤总DNA为模板,利用PCR技术扩增得到该l条chs基因编码区,通过TA克隆、测序和同源比对及进化分析表明:该基因为放线菌来源chs基因.分别在该基因5’末端和3’末端分别引入的限制酶NcoI和EcoR I酶切位点,利用上述2种限制酶分别酶切导入到psimple-T/chs载体和原核表达pET32a,凝胶回收目的片段后,将二者连接并转化大肠杆菌感受态细胞,转化子经菌液PCR筛选、双酶切鉴定后,3730测序结果表明,该基因全长编码区为1089 bp,推测该基因编码全长为362个氨基酸残基,等电点(PI)为5.41、分子量为3 965道尔顿含有CHS保守功能区的酸性蛋白质.分析表明,该基因与Streptomyces lividans来源的查尔酮合成酶RppA基因核苷酸相似性高达93％,氨基酸序列相似性高达87.70％.测序结果表明,该基因已经成功插入到pET32a载体中.     

土壤污染刑事责任探究

土壤污染是制约生态农业发展的罪魁祸首。制定《土壤污染防治法》对污染土壤的行为进行惩治,无疑是解决问题的一种最为有效的途径。立法最重要的问题是责任的明晰。法律责任有行政责任、民事责任和刑事责任,土壤污染刑事责任应当有别于其他污染。在立法模式上,土壤污染的刑事责任应当既在刑法中规定,也在土壤污染防治法中进行规定。     

沉井冲水掏土纠偏技术的工程应用

软粘土地基处理的方法很多 ,其中对已有倾斜建筑物地基处理的技术难度较大 .本文介绍了在工程实际应用的一种新方法 :沉井冲水掏土纠偏法     

流民群体市民化的城市社会环境及制度建设——以成都市返乡农民工和失地农民为例

流民群体是制度变迁和社会转型产生的特殊群体,主要包括进城农民工、返乡农民工、失地农民。流民群体要在城市新的环境中获得生存的能力,以适应环境变化,必须融入城市生活,成为城市市民。“城市社会环境”对于城乡流民群体的市民化有着特殊的意义。对返乡农民工和失地农民,成都市政府做了有益的政策探索。