Effect of sodium chloride and cadmium on the growth,oxidative stress and antioxidant enzyme activities of Zygosaccharomyces rouxii

Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(NaCl) and Cd are poorly understood. This study investigated the effects of NaCl and Cd on the growth, oxidative stress and antioxidant enzyme activities of Z. rouxii after stress treatment for 24 h. Results showed that NaCl or Cd alone negatively affected the growth of Z. rouxii, but the growth-inhibiting effect of Cd on Z. rouxii was reduced in the presence of NaCl. Flow cytometry assay showed that under Cd stress, NaCl significantly reduced the production of reactive oxygen species(ROS) and cell death of Z. rouxii compared with those in the absence of NaCl. The activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) of Z. rouxii were significantly enhanced by 2%–6% NaCl, which likely contributed to the high salt tolerance of Z. rouxii. The POD activity was inhibited by 20 mg L-1Cd while the SOD and CAT activities were enhanced by 8 mg L-1 Cd and inhibited by 20 mg L-1 or 50 mg L-1 Cd. The inhibitory effect of high-level Cd on the antioxidant enzyme activities of Z. rouxii was counteracted by the combined use of NaCl, especially at 6%. This probably accounted for the decrease in Cd-induced ROS production and cell death of Z. rouxii after incubation with NaCl and Cd. Our work provided physiological clues as to the use of Z. rouxii as a biosorbent for Cd removal from seawater and liquid highly salty food.     

The effect of environmental factors on spatial variability in land use change in the high-sediment region of China’s Loess Plateau

In areas with topographic heterogeneity, land use change is spatially variable and influenced by climate, soil properties, and topography. To better understand this variability in the high-sediment region of the Loess Plateau in which soil loss is most severe and sediment diameter is larger than in other regions of the plateau, this study builds some indicators to identify the characteristics of land use change and then analyze the spatial variability as it is affected by climate, soil property, and topography. We build two indicators, a land use change intensity index and a vegetation change index, to characterize the intensity of land use change, and the degree of vegetation restoration, respectively. Based on a subsection mean method, the two indicators are then used to assess the spatial variability of land use change affected by climatic, edaphic, and topographic elements. The results indicate that: 1) Land use changed significantly in the period 1998-2010. The total area experiencing land use change was 42,302 km2, accounting for 22.57% of the study area. High-coverage grassland, other woodland, and forest increased significantly, while low-coverage grassland and farmland decreased in 2010 compared with 1998. 2) Land use change occurred primarily west of the Yellow River, between 35 and 38 degrees north latitude. The four transformation types, including (a) low-coverage grassland to medium-coverage grassland, (b) medium-coverage grassland to high-coverage grassland, (c) farmland to other woodland, and (d) farmland to medium-coverage grassland, were the primary types of land use change, together constituting 60% of the area experiencing land use change. 3) The spatial variability of land use change was significantly affected by properties of dryness/wetness, soil conditions and slope gradient. In general, land use changed dramatically in semi-arid regions, remained relatively stable in arid regions, changed significantly in clay-rich soil, remained relatively stable in clay-poor soil, changed dramatically in steeper slopes, and remained relatively stable in tablelands and low-lying regions. The increase in vegetation coincided with increasing changes in land use for each physical element. These findings allow for an evaluation of the effect of the Grain to Green Program, and are applicable to the design of soil and water conservation projects on the Loess Plateau of China.     

北京交通网络拓扑结构及可达性格局历史变化研究

基于过去800年（1160～2000年）北京城市交通网络时间序列数据,研究了北京交通网络的发展变化。主要从交通网络的拓扑结构、可达性等角度分别对网络直径、平均最短路径长度、平均聚集指数、相对可达性等指标进行了定性定量分析。研究结果表明：第一,北京交通网络扩张呈“两段式”特点：前数百年只加密路网,近53年网络直径扩张了2．62倍;第二,从网络拓扑结构的角度分析,北京过去800年交通网络度分布结构呈现良好的一致性,交通网络中顶点与路段的比例保持不变,网络内部联系日趋紧密;第三,北京交通网络可达性格局趋于有序：从金元时期的不规则格局发展为明清时期的椭圆形格局,建国后呈圆盘形格局扩张,但可达性中心由天安门向西北方向偏移至阜成门处。通过搜集研究北京过去800年的交通网络数据,本文记录了北京交通网络演化的全过程,并揭示了其演化过程中蕴含的宏观规律。     

TEQC在GPS数据分析及多路径效应中的应用研究

介绍了TEQC及其辅助软件QCVIEW 32的功能以及在DOS系统下的操作命令,并运用这两种软件对试验数据进行了GPS多路径误差分析,得出了影响多路径误差的部分因素,试验证明,TEQC可以方便地用于多路径误差分析,并能取得良好的效果。     

川西高原红原机场建设气象条件可行性分析

在为川西高原红原机场气候论证观测取得连续一年多资料的基础上,结合相邻的红原县、阿坝县气象站30年整编气候资料,利用山地气候推算分析方法,对机场场址的气候资料进行推算分析,根据推算的气候资料结合实际观测资料,对机场建设可能产生影响的气象要素进行分析评估,形成了可行性综合论证报告。本研究为红原机场工程建设提供了气象科学依据,取得了良好的社会效益和经济效益。     

Notes邮件系统常见问题解析

Lotus Domino/Notes邮件系统现已成为气象部门必不可少的工具,它是目前最为流行的文档数据库系统之一,作为群件系统,它利用自身强大的功能,在企业、政府办公自动化方面的应用越来越广.本文分析了气象部门在使用Notes邮件系统过程中通常会遇见的数据库出错、服务器无响应及用户切换等一些问题,并给出了相应的解决办法...     

Sorption of heavy oil onto Jiaozhou Bay sediment

The sorption of heavy oil onto sediment collected from Jiaozhou Bay was studied in a series of kinetic and equilibrium experiments using NaCl solutions. The effects of temperature, salinity, and pH of the medium on sorption behavior were investigated.Sorption equilibrium of the heavy oil and sediment was established within 60 min. The process was shown to follow a pseudo-second-order kinetic rate model. The sorption rate decreased with increasing initial heavy oil concentration in the solution. Batch equilibrium experiments showed that the sorption isotherm could be described by the Freundlich model. The standard free energy change and enthalpy change at the temperatures studied (283, 288, 293, and 298 K) were negative. These findings indicated that the process was spontaneous and exothermic. Salinity, pH and temperature influenced sorption performance. Sorption was favored by higher concentrations of NaCl, by lower pH values and by lower temperatures.     

Rapid afterslip and short-term viscoelastic relaxation following the 2008 M_W7.9 Wenchuan earthquake

Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are assumed to be afterslip on the earthquake rupture plane and viscoelastic relaxation of coseismiclly stress change in the lower crust or upper mantle. We firstly use the constrained least squares method to find an afterslip model which can fit the GPS data best. The afterslip model can explain n...     

广西岩溶洞穴沉积物与地震记录初探

广西是西南地区的一个岩溶大省,其岩溶面积占土地面积的42%.广西岩溶洞穴十分发育,至少有6万个洞穴.洞穴景观资源丰富,为广两的旅游创造了大量的财富.岩溶洞穴沉积物不仅具有旅游开发价值,而且蕴含了丰富的古气候环境信息,同时,也是地震信息的存储器,是研究地震遗迹的良好材料.地震活动不仅导致岩溶洞穴及洞穴沉积物发生破裂、坍塌...     

磁暴活动与云南新一轮地震活跃期分析

对通海地磁台记录的磁暴(K指数≥5)年频次分析发现,磁暴活动的周期有强弱之分,与云南省地震活跃期和平静期对比分析看到,磁暴活动较强的周期时段与云南地震的活跃期相对应,磁暴活动较弱的周期时段与云南地震活动平静期相对应.目前,云南地震平静期已持续15年,即将进入第Ⅴ活跃期,大震发生的危险逐日增强.磁暴发生的数目和太阳活动有...