GIS支持下的江西省水土流失生态环境风险评价

以江西省为例 ,在合理地选择对水土流失有影响的生态环境因子基础上 ,利用土壤侵蚀公式计算值 ,按环境因子对水土流失影响的危险程度 ,对各环境因子进行风险打分 ,在 ARC/ INFO中运用主成分分析方法 ,确定各环境因子的权重 ,同时选出主成分 ,把主成分与其权重相乘得到风险图 ,在 ARCVIEW下定出风险等级 ,从而对江西省的生态环境风险性作出评价     

Biological activation of hydrous ferric oxide for reduction of hexavalent chromium in the presence of different anions

Shewanella alga BrY, a dissimilatory iron reducing bacterium (DIRB), transformed inert ferric oxides that are common in sediments, aquifer material and passivated permeable reactive iron barriers (PRBs), producing dissolved and sorbed Fe(II) capable of rapidly reducing and immobilizing Cr(VI). The effect of groundwater chemistry on the formation and reactivity of such microbial-produced, abiotic reductants was investigated. Batch reactors with high carbonate concentration (10 mM) were the most reactive, removing 66.0% ± 2.8 of Cr (VI) (76 mg/l) from liquid phase within 5 min. Treatments with high concentrations of sulfate (5.2 mM), chloride (10 mM), phosphate (1 mM) or silica (0.75 mM) were less reactive (about 40% removal). Loss of reactivity was observed possibly due to oxidation of Fe(II) (sorbed and dissolved) by Cr(VI). Normalization of Cr(VI) removal to the mass of biogenic solid present showed the following molar Cr/Fe ratios in solid phase: 0.185 ± 0.041 (carbonate), 0.146 ± 0.013 (sulfate), 0.092 ± 0.010 (silica), 0.075 ± 0.012 (phosphate) and 0.062 ± 0.012 (chloride). Overall, these results show that bacterial transformation of inert ferric oxides can contribute to the (abiotic) natural attenuation of Cr(VI) in and around PRBs, and that groundwater chemistry is an important determinant of biogenic solids reactivity.     

基于RS与GIS的城市化过程中农业用地景观格局变化研究

利用1988、1997和2002年3期的TM遥感影像数据和地理信息系统（GIS）技术得到广州市白云区农业用地景观变化图,计算各时期农业用地景观格局指数．通过比较分析,发现1988～2002年白云区农业用地景观面积急剧萎缩,主要向水体、城镇用地和开发用地转移,农业用地景观的斑块数、破碎度、分离度、形状指数趋于升高,斑块的平均面积和周长不断减少．采用逐步回归法对影响农业用地景观变化的内在因素进行了分析,结果表明农业用地景观类型的转化主要与高程、坡度、距城市中心距离、距城镇用地距离、距林地距离有关,其中以高程、距城镇用地距离、距城市中心距离影响最甚．     

南瓜汁的酶解法制取及其在发酵面制品中的应用

研究了南瓜酶法制汁工艺,确定了最佳酶法制汁工艺参数。结果表明:面粉中添加一定量的南瓜能够改善制品的色泽,增加制品的光泽,还能改善产品的质地和风味。但添加量过高会直接影响制品的感官品质,降低面坯的发酵速度;添加过少则失去研究的意义。500 g面粉中添加125 g南瓜汁、3 g酵母调制面团,经2 h发酵,所得制品最优。     

图书馆资源政府采购研究

回顾政府采购制度的发展历程，并揭示图书馆文献资源政府采购制度存在的问题．为解决现存问题．借鉴国内成功经验。而构建佛山地区图书馆文献资源政府集团采购模式。提出完善图书馆文献资源政府采购制度，管理体制与机制的创新。     

中药复方制剂对大鼠和母猪骨质疏松症的防治效果试验

探讨中药复方对实验性大鼠骨质疏松症的预防和治疗作用,并在此基础上探索该中药对成年经产高龄母猪骨质疏松症的预防效果。对102只3月龄SPF级SD雌性大鼠用维甲酸造模并进行中药防治试验,造模结束和药物治疗结束后对大鼠进行骨密度检测、骨组织形态检测与血液生化指标(Ca、P、BALP和TRACP-5b)检测。同时,将35头6胎~8胎经产高龄母猪,4岁~5.5岁体重220kg^300kg长大二元杂母猪随机分为空白组、中药复方高、中、低(B1、B2、B3)3个剂量组,连续给药20d,检测母猪血液生化指标(Ca、P、TRACP-5b、CTX-Ⅰ、BALP和PINP)。结果表明,与模型组相比,中药组大鼠血清水平有显著降低,骨密度增加,骨微观结构得到改善;与空白组相比,中药中剂量组和高剂量组母猪血清BALP及PINP水平显著升高,TRACP-5b及CTX-Ⅰ水平显著降低。结果表明该中药复方制剂对大鼠和猪骨质疏松症的治疗有良好效果。     

Antitumor effects of HSV-tk and cytosine deaminase double suicide gene mediated by adenovirus on cholangiocarcinoma cells in vitro

AIM: To study the antitumor effects of HSV-tk and cytosine deaminase double suicide gene system on cholangiocarcinoma cells in vitro. METHODS: Recombinant adenovirus vector carring HSV-tk and cytosine deaminase double suicide gene was constructed and was transfected into QBC939 huamn cholangiocarcinoma cells. The antitumor effects were observed in vitro in comparison with a single suicide gene system. RESULTS: By transfection, HSV-tk and (or) cytosine deaminase double suicide gene gained high expression in tumor cells. Compared with single suicide gene system, this double gene system presented higher sensitivity, stronger antitumor effect and bystander effect. CONCLUSION: HSV-tk and cytosine deaminase double suicide gene system has a powerful antitumor effect on cholangiocarcinoma cells.     

粤北岩溶山区农业水土环境问题及对策

粤北岩溶山区是广东省主要的贫困地区之一,自然环境先天脆弱,水土流失严重、水资源短缺、旱涝灾害频繁等一系列生态问题已成为制约当地社会经济可持续发展的关键因素。在广泛、深入调查的基础之上,分析了粤北岩溶山区农业水土环境问题的现状及主要成因,提出了改善农业生态环境,促进农业水土资源可持续发展的针对性措施。     

Intensive management of a bamboo forest significantly enhanced soil nutrient concentrations but decreased soil microbial biomass and enzyme activity: a long-term chronosequence study

Purpose

Intensive long-term management practices in forest ecosystems can markedly influence soils’ physicochemical and microbial properties. However, their effects on the magnitude of nutrient pools and activities of enzymes regarding nutrient cycling in subtropical forest soils remain unclear. This study aimed to examine effects of long-term intensive management (organic mulching and chemical fertilization) on concentrations of different C, N, and P fractions and activities of enzymes involved with nutrient cycling in a subtropical Lei bamboo (Phyllostachys violascens) forest soil.

Materials and methods

Soil samples were taken from a chronosequence of Lei bamboo forests with intensive management spanning 0, 5, 10, and 15 years. Concentrations of various forms of C, N, and P, as well as activities of β-glucosidase, cellobiohydrolase, urease, protease, and acid phosphatase were measured.

Results and discussion

The results revealed that the concentrations of different classes of C (water-soluble organic C, hot-water-soluble organic C, and readily oxidizable C), N (NH₄⁺-N, NO₃^?-N, and water-soluble organic N), and P [resin-inorganic P (P_i), NaHCO₃-P_i, NaHCO₃-organic P (P_o), NaOH-P_i, NaOH-P_o, HCl-P_i, and residual-P] were enhanced markedly with prolonged duration of intensive management. Furthermore, activities of β-glucosidase, cellobiohydrolase, urease, protease, and acid phosphatase were increased following a 5-year treatment, while they were markedly reduced from 5- to the 15-year treatments. The 15 years of intensive management significantly reduced microbial biomass C and N concentrations by 8.2% and 31.9%, respectively, compared to the control.

Conclusions

We concluded that long-term intensive management led to the accumulation of C, N, and P, while it negatively impacted microbial biomass and activities of enzymes involved in nutrient cycling in subtropical Lei bamboo forest soils. Consequently, a reduction in chemical fertilizers should be considered toward the long-term sustainable development of subtropical Lei bamboo forests.