不同收入来源对甘肃省城乡收入差距的影响研究

收入由多个来源部分组成,城乡收入差距的变化是收入来源各部分变动的综合反映,透过收入来源的角度可以清晰地判断城乡收入差距产生的根源.本文运用泰尔指数及其分解方法,对2003-2008年甘肃省城乡收入差距大小及其在总区域收入差距中的贡献变化趋势进行测度,并利用要素分解法实证分析了不同收入来源对城乡收入差距的影响,以此揭示甘肃省城乡收入差距产生的原因.研究发现,城乡收入差距在总区域收入差距中的贡献是递增变化的,已经成为影响甘肃省居民收入差距的重要因素;工资性收入是目前拉大城乡收入差距最为重要的原因,而家庭经营性收入则起着缩小差距的作用,转移性收入和财产性收入在总收入中所占比例很小,但转移性收入对城乡收入差距的贡献却不容轻视.基于研究结果,提出了增加农民非农收入、推进农业产业化进程和完善城乡间收入再分配制度等政策建议,以期为欠发达地区缩小城乡收入差距带来一些启示.     

河道沉积物中磷的分布、吸附及释放规律研究

为科学评价磷在河道沉积物中的环境行为,在模拟条件下研究了上海市进木港和苏州河沉积物中磷的分布形态、吸附特征及释放规律.结果表明:(1)2种沉积物中碎屑钙磷(De-P)浓度最高,闭蓄态磷(Oc-P)次之,其他形态磷浓度相对较低,而活性磷中以铁磷(Fe-P)为主;(2)2种沉积物对磷的吸附均符合线性方程,在4.0h时基本达...     

初始pH值对磷酸盐还原除磷的影响研究

以超高盐（盐度7％,以NaCI计）高磷榨菜废水为研究对象,考察了初始pH值对磷酸盐还原进程的影响。实验结果表明,初始pH值对磷酸盐还原除磷效能影响显著。初始pH为8时,磷酸盐还原除磷率达到最高,平均值为65．45％。同时,初始pH值还会影响污泥中活性磷的形成以及基体对磷化氢的吸附。此外,偏碱性有利于磷形态转化,且BD-P（主要是一些可溶性的、还原性强的、带有Fe-P化合物的集合）含量的高低调控着生物膜内间隙水中溶解态可反应性磷（DRP）和可还原水溶态磷（RSP）含量,最终决定着磷酸盐还原进程。随着初始pH值的升高,污泥对磷化氢的吸附能力降低导致污泥中结合态磷化氢（MBP）含量不断减少。     

射阳县黄沙港流域面源污染现状及防治对策

针对农村面源污染日渐突出的问题,以农村饮用水源地黄沙港为例分析了农村面源污染的现状和成因,并从乡镇规划、生活污水处理工艺选择、畜禽水产业污染治理、农药化肥的施用、农业废弃物利用技术等方面提出防治措施。     

硝酸盐对反硝化除磷过程的影响分析

在厌氧/缺氧间歇反应器内考察了硝酸盐进水浓度及进水方式对反硝化除磷过程的影响。结果表明：在缺氧阶段,反硝化除磷菌(DPBs)可将硝酸盐转化为亚硝酸盐,当硝酸盐浓度较低时,DPBs以亚硝酸盐为电子受体吸磷。进水COD浓度为220 mg/L,正磷浓度为6.8 mg/L,硝酸盐初始浓度为26 mg/L时,系统达到最佳脱氮除磷效果,期间亚硝酸盐浓度积累至10.71 mg/L。采用连续流投加硝酸盐的方式更利于氮磷的高效去除。     

Sources and Framing of Fracking: A Content Analysis of Newspaper Coverage in North Carolina,New York,and Pennsylvania

Research across several decades has mapped the way complex environmental issues with complicated policy implications are often differentially framed within the media, public, and policy agendas with major implications for how they are understood, discussed, and decided. Building on this work, this this study compared news coverage of the debate over natural gas “fracking” in New York, Pennsylvania, and North Carolina between the period 2008 and 2013. Examining state newspapers, the analysis evaluated the types of sources used, the assertions of these sources, and how the issue of fracking was framed. From a general perspective, this study reveals how differences in framing of an environmental and scientific controversy can be attributed to the locally relevant sources used in reporting, as well as the political, economic, and social factors that might be unique to a state. Specific to the debate over natural gas “fracking,” this study adds to our understanding of how such state-based factors influence the portrayal of the issue in the news media.     

Assessing stress response of Stylophora pistillata towards oil and phosphate pollution in the Gulf of Aqaba,using molecular and biochemical markers

Crude oil (from oil terminal) and raw phosphate (from phosphate port) pollution are responsible for the lowered health conditions of coral reefs at their vicinity in the Jordanian coast of the Gulf of Aqaba. Both in situ incubations and ex situ laboratory exposure experiments were used to study the effects of those pollutants on corals, by using molecular and biochemical biomarkers in the coral Stylophora pistillata. For ex situ part of the experiment, crude oil and raw phosphate were added to a final concentration of 500?ppm for both pollutants. The DNA damage was assessed by Comet assay, while biochemical stress markers were reassessed by lipid peroxidation (LPO) test. Although the corals looked healthy from outside, the use of stress biomarkers indicated that they are under high pressure at the cellular level. The corals incubated with oil and phosphate had more DNA damage and LPO in comparison with the control samples. The results obtained suggest that the use of stress biomarkers can be used as important prognostic tools for examining the sub-lethal stress on corals before their death.     

青萍(Lemna minor L.)对氮磷的吸收特征

以西部地区优势浮萍品种青萍为实验对象,研究了青萍对不同浓度硝态氮和磷酸盐的吸收特征。结果表明,硝态氮浓度在1～10 mg/L范围内,青萍对硝态氮有较好的吸收效果,M-M方程可以较好地描述硝态氮浓度与青萍对硝态氮的吸收速率之间的关系,通过M-M方程拟合得到青萍对硝态氮的最大吸收速率为0.1167 mg/(g FW.h),亲和力常数为6.9274。磷酸盐浓度在0.1～1.0 mg/L范围内,青萍对磷酸盐也有较好的吸收效果,二次多项式回归可以较好地描述青萍吸收速率与磷酸盐浓度的关系,回归方程得到青萍对磷酸盐的最大吸收速率为0.0193 mg/(g FW.h),对应磷酸盐浓度为0.6 mg/L。     

Subcellular distribution and toxicity of cadmium in Potamogeton crispus L

The submerged macrophyte Potamogeton crispus L. was subjected to varying doses of cadmium (0, 20, 40, 60 and 80 μM) for 7 d, and the plants were analyzed for subcellular distribution of Cd, accumulation of mineral nutrients, photosynthesis, oxidative stress, protein content, and ultrastructural distribution of calcium (Ca). Leaf fractionation by differential centrifugation indicated that 48-69% of Cd was accumulated in the cell wall. At all doses of Cd, the levels of Ca and B rose and the level of Mn fell; the levels of Fe, Mg, Zn, Cu, Mo, and P rose initially only to decline later. Exposure to Cd caused oxidative stress as evident by increased content of malondialdehyde and decreased contents of chlorophyll and protein. Photosynthetic efficiency, as indicated by the quenching of chlorophyll a fluorescence (Fv/Fm, Fo and Fm), decreased significantly, the extent of decrease being directly proportional to the concentration of Cd. Increased amounts of precipitates of calcium were noticed in the treated plants, located either outside the cell membrane or in chloroplasts, mitochondria, the nucleus, and the cytoplasm whereas control plants showed small deposits of the precipitates around surface of the vacuole membrane and in the intercellular space but rarely in the cytoplasm. Photosynthetic efficiency and oxidative stress could be used as indicators of physiological end-points in determining the extent of Cd phytotoxicity.