Fluctuations of Population Size and Structure in the Northern Mole Vole: Preliminary Analysis

Long-term stationary studies on the ecology of the northern mole vole (Ellobius talpinus Pall.), performed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics and structure. The analysis shows that, to reveal cyclic fluctuations of population size in this species, the period of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population cycle in E. talpinus has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the population is characterized by certain features of family structure, age composition, birth and death rates, and the composition of migrants.     

红壤中结合态磷在酸化条件下的变化及其相互关系

以浙江沿海地区的红壤为研究对象，通过浸滤过程，研究了在酸化条件下，红壤中可溶笥结合态磷的变化和它们之间的相关关系，结果显示，红壤中可溶性Fe-P比Ca－P、Al－P对酸度的变化更为敏感；当红壤中可溶性磷的原始含量较高时，随酸度的增强从固相中释出的趋势更明显；在酸化过程中、红壤中不同可溶性结合态磷之间呈现出不同的相关关系，这归因子它们对酸化敏感性的差异。     

再论含金硫化物矿物中能否存在负价金问题──答李九玲等同志

本文从讨论金属结合能何以具有表面化学位移的原因开始,从金属团簇的一般性质出发,论证了金属结合能自尺寸大于1nm的团簇到金属微粒再到块体金属具有连续过渡性;金属结合能与粒径R呈正相关;与1／R具线性负相关关系,认为金微粒或团簇具有1．1eV以上的结合能负位移是可能的。并指出李九玲等同志在“评<含金硫化物矿物中不可能存在负价金>”一文中引用的某些衬底材料上的金团簇呈现结合能正位移的数据是由于这些金困簇已与其衬底材料发生了键合作用造成的,它们不能作为否定金属结合能位移与粒径呈正相关的依据。同时,笔者从“化学结合金”在氰化过程中并未被氧化成正离子金判断,它不应是负价金。并由同质并能位移与粒径可具负相关关系推论,“化学结合金”应是合企硫化物矿物中可存在的少量微粒碲金矿、碲金银矿等中的正离子金。笔者强调在讨论企的价态问题时应采用Allred－Rochow电负性数据而非常用的Pauling电负性数据,并再次指出含金硫化物矿物中不可能有负价金存在。     

Fetal urinary insulin-like growth factor I and binding protein 3 in bilateral obstructive uropathies

Fetal urinary concentrations of insulin-like growth factor I (UIGF-I) and binding protein 3 (UIGFBP-3) were determined in patients with prenatal diagnosis of bilateral obstructive uropathy. Patients were retrospectively assigned to three groups, on the basis of outcome: group 1, termination of pregnancies (n = 11) with sonographic evidence of severe oligohydramnios or renal dysplasia, confirmed at histological examination; group 2, patients (n = 10) with postnatal plasma creatinine > 50 μmol/1 at the age of 1 year (1 yr-pCreat); and group 3, patients (n = 16) with 1 yr-pCreat ≤ μmol/1. The results show a significant increase in UIGF-I and UIGFBP-3 in groups 1 (18 159 ± 9083 pg/ml; 2657 ± 669 ng/ml) and 2 (1574 ± 847 pg/ml; 176 ± 50 ng/ml) in comparison with group 3 (35 ± 6 pg/ml; 21 ± 2 ng/ml). UIGF-I and UIGFBP-3 were significantly correlated with postnatal plasma creatinine, and were both sensitive (90 per cent; 80 per cent) and specific (88 per cent; 88 per cent) for prediction of elevated 1 yr-pCreat (>50 μmol/1). Fetal urinary IGF-I and IGFBP-3 are increased in severe fetal bilateral obstructive uropathy, possibly reflecting tubular dysfunction or/and increased synthesis consequent upon fetal kidney injury. Their predictive value for postnatal renal function needs further assessment.     

土壤溶解性有机质荧光特征及其与铜的络合能力

选取4种不同类型土壤和腐熟鸡粪,透析提取溶解性有机质(DOM),通过凝胶色谱、三维荧光光谱测定并分析了DOM的相对分子质量(M_r)分布、化学结构特征及其与铜的结合能力.结果表明,鸡粪DOM相对分子质量积分面积远高于其他样品,表现出其具有较高的有机物含量,泥炭土次之.暗棕壤、褐土和黑土较低,仅为鸡粪积分面积的4.5%~5%.鸡粪在中分子量段积分面积约占总物质的34.1%,低分子量段和高分子量段分别约占41.7%和24.2%.荧光光谱分析表明,各样品均出现类蛋白荧光峰(E_x/E_m=240~270/300~350 nm),在中、高分子量段(M_r500)暗棕壤存在的荧光峰消失.泥炭土出现了较为独特的可见光区类富里酸荧光峰(E_x/E_m=325/420 nm),该荧光峰和黑土的荧光峰在中、高分子量段(M_r500)都产生了红移现象.鸡粪分别出现了和黑土类似的紫外区类富里酸荧光峰,以及和泥炭土类似的可见光区类富里酸荧光峰,以及一类独特的类蛋白荧光峰(E_x/E_m=280/350 nm),但这种类蛋白荧光峰在中分子量段(500M_r12 000)消失.分析表明泥炭土与Cu的络合常数(lg K)为4.13,其他3种土壤与Cu的络合常数较小且差别不大,集中在2.10~3.10之间.鸡粪与Cu的结合能力最大,络合常数达到6.66.     

两相厌氧工艺的研究进展

为了了解两相厌氧工艺的研究状况,对两相厌氧反应器及相分离方法进行了综述,并指出了今后两相厌氧工艺的研究方向.     

不同经济发展阶段区域经济发展差异比较

在介绍区域经济发展阶段各种理论及划分方法的基础上,通过计算1985-2004年间,广西崇左市、安徽滁州市、江苏南通市经济发展的变化轨迹,确定不同区域经济发展阶段.利用偏离-份额分析法对区域经济发展水平进行研究,表明崇左市经济结构较差,结构对于经济增长的贡献小且竞争能力较弱;滁州市经济中增长快的产业部门比重较大,总体经济结构较好,结构对于经济增长具有一定贡献,竞争能力较强;南通市经济中朝阳的、增长快的产业部门比重大,总体经济结构好,结构对于经济增长的贡献大,且各产业部门总的增长势头大,具有很强的竞争能力.建议:①崇左市参与中国-东盟自由贸易区、中越"两廊一圈"经济带以及泛珠三角经济区域,吸收泛珠三角经济区的产业转移,加快发展国际贸易.②滁州市应融入南京都市圈,吸引和承接东部地区的产业转移,注意生态城市建设,发展循环经济,实现经济和生态环境的综合协调发展.③南通市应把资源节约型的增长模式和消费方式作为经济增长方式转变的核心,提升产业的综合竞争力,最终实现经济社会协调发展.     

Quantification of the interactions between Ca,Hg and extracellular polymeric substances (EPS) of sludge

The interactions between metals (Ca²⁺ and Hg²⁺) and extracellular polymeric substances (EPS) extracted from the aerobic and anaerobic sludge in wastewater treatment reactors were investigated using a combination of zeta potential measurement and 3-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy with parallel factor (PARAFAC) analysis. Results show that Ca²⁺ had no substantial effects on the EEM fluorescence spectra of the EPS, but their zeta potentials increased with the increasing Ca²⁺ dosage. However, Hg²⁺ had a significant effect on the EEM fluorescence spectra of the EPS, while their zeta potentials seemed not to be affected by the dose of Hg²⁺. The interactions between Hg²⁺ and EPS were elucidated using the fluorescence quenching with PARAFAC analysis, while the interactions between Ca²⁺ and EPS were evaluated by the zeta potential technique. The binding constants for Hg²⁺ and EPS were two orders of magnitude higher than those for Ca²⁺ and EPS, suggesting that the binding mechanisms between Ca²⁺ and EPS were different from those between Hg²⁺ and EPS. The results might be useful for understanding the roles of EPS in bacterial self-protection against heavy metals and the aggregate formation mechanisms through ionic bridging interactions.     

Genotoxicity of chromium in vitro on yeast: Interaction with DNA†

The genotoxicity of chromium chloride was investigated in cells of D₇ strain of Saccharomyces cerevisiae harvested either from logarithmic or stationary growth phase.

A weak induction of mifotic gene conversion and point reverse mutation was obtained when the incubations were performed using phosphate buffer. No genetic effect was observed when the incubations were performed using Tris‐HCl buffer.

The experiments with ⁵¹Cr radiotracer demonstrated that Cr³⁺ ion enters the yeast cells and binds to DNA even if the incubation mixture was performed with Tris HCl buffer. This behaviour could be due to the highest concentration of CrCl₃ that cause some damages to cytoplasmatic membrane.     

The Influence of Varying Algal Biomass On Contaminant Exposure in Benthic-Planktonic Mesocosms: Copper (Ii)

A series of mesocosms was exposed to a suite of light treatments and nutrient enrichment in order to generate algal communities of varying biomass. the influence of this biomass on the speciation of copper (II) was studied. Distribution coefficients (_Kd,Lkg-1) were relatively high (log_Kd = 5 to 7), indicative of robust trace metal sequestration, and were likely controlled by the particulate organic carbon content (foc). Differences in _Kd over time and among treatments were significant, as was the relationship between _Kd and foc. Fluorescence quenching was used to determine binding capacities (_Lt, M) and their associated binding constants (_Kcond,M^-1) in order to model the solid phase copper speciation. the _Kcond ranged between 2.1 and 5.2 × 10¹²M^-1, indicating a very strong copper-ligand complex, and was higher in mesocosms that received more light. the light _Lt increased over time, dramatically after the nutrient enrichment, but did not vary systematically among light treatments. _Lt ranged from 7.2 × 10- 7 to 4.9 × 10- 5 M. the large magnitudes of _Kd, _Kcond and _Lt ensured that greater than 97% of total copper in the mesocosms was complexed by organic matter. the total copper concentration ([Cu]_T, M) needed to reach a target dissolved copper concentration of 10^-12.5 M (pCu = 12.5) was determined for each mesocosm over time. [Cu]_T was between 8.02 × 10^-5 and 3.41 × 10^-2 M, and increased over time. the [Cu]_T normalized to the target pCu (Effective Dose Ratio, EDR) increased directly with increases in algal biomass, indicating a direct link between system productivity and copper exposure. Approximately 45% of the variance in EDR was explained by variance in total biomass, while the residual variance in EDR was due likely to differences in the strengths of particle associations and magnitude of binding capacities.