Correlative changes in metabolism and DNA damage in turbot (Scophthalmus maximus) exposed to benzo[a]pyrene

Juvenile turbot (Scophthalmus maximus) were injected intraperitoneally with either corn oil or 5 mg/kg benzo[a]pyrene (BaP) dissolved in corn oil and sampled I and 3 days after injection. After 1 day, no elevation of 7-ethoxyresorufin O-deethylase (EROD) activity was observed, however bile metabolites (BaP-7,8 dihydrodiol representing 70% of the total metabolites) and a single hepatic DNA adduct spot (0.47 adducts/10(8) nucleotides) identified by 32P-postlabelling were formed. No BaP metabolites or DNA adducts were observed in either control or carrier control fish. Fish sampled after 3 days reported 5-fold higher (P < 0.05) levels of EROD activity, a shift in the bile metabolite profile towards BaP phenol formation (1OH and 30H BaP comprising up to 60% of total metabolites detected) and the formation of two adduct spots (0.86 and 0.71 adducts/10(8) nucleotides). These results show that BaP can be metabolised and form hydrophobic DNA adducts in turbot without EROD elevation. Following EROD elevation, a shift in the profile of both BaP metabolites and BaP metabolite-DNA interactions occurs indicative of other oxidative processes.     

The concentration and isotopic composition of carbon in basaltic glasses from the Juan de Fuca Ridge, Pacific Ocean

The abundance and 13C/12C ratios of carbon were analyzed in basaltic glass from twenty locations along the Juan de Fuca Ridge using a 3-step combustion/extraction technique. Carbon released during the first two combustion steps at 400-500 degrees C and 600-650 degrees C is interpreted to be secondary, and only the carbon recovered during a final combustion step at approximately 1200 degrees C is thought to be indigenous to the samples. For carbon released at approximately 1200 degrees C, glasses analyzed as 1-2 mm chips contained 23-146 ppm C with delta 13C values of -4.8 to -9.3%, whereas samples crushed to 38-63 microns or 63-90 microns yielded 56-103 ppm C with delta 13C values of -6.1 to -9.2%. The concentrations and isotopic compositions of the primary carbon dissolved in the glasses and present in the vesicles are similar to those previously reported for other ocean-ridge basalts. The Juan de Fuca basaltic magmas were not in equilibrium with respect to carbon when they erupted and quenched on the sea floor. Evidence of disequilibrium includes (1) a large range of carbon contents among glasses collected at similar depths, (2) a highly variable calculated carbon isotopic fractionation between melt and vapor determined by comparing crushed and uncrushed splits of the same sample, and (3) a lack of correlation between vesicle abundance, carbon concentration, and depth of eruption. Variations in carbon concentration and delta 13C ratios along the ridge do not correlate with major element chemistry. The observed relationship between carbon concentrations and delta 13C values may be explained by late-stage, variable degrees of open-system (Rayleigh-like) degassing.     

落后地域经济瓶颈的诊断分析：以安康地区粉列

以区域系统运动理论和 贫困的恶性循环理论基础，运用图论中“度”的理论和方法，并以安康地区为例，对区域瓶颈因素诊断的理论和方法做了尝试性的研究，具有较强的理论基础的较客观的研究结果。     

落后地域经济瓶颈的诊断分析——以安康地区为例

以区域系统运动理论和贫困的恶性循环理论为基础，运用图论中“度”的理论和方法，并以安康地区为例，对区域瓶颈因素诊断的理论和方法做了尝试性的研究，具有较强的理论基础和较客观的研究结果。     

森林生长——环境间关系的模型建造

一、基本原理确定性增长模型的作用可以阐述为在众多环境因素(能够测定的)的基础上估算树木生长(通常是不可直接测定的)。然而,由于树木生长受到多种环境条件的影响,因此,有必要找到一个既实际又便于使用的模型结构,将环境诸因素统一起来。在这里,实际蒸散量概念具有很大价值。实际蒸散量被定义为:在野外条件下,通过蒸发和蒸腾而损失的水量。森林所损失的水量中,绝大部分是树木蒸腾而损失掉的。     

鲁西北平原农业发展的驱动力与对策

可持续农业发展的动力是对东昌府区农业发展最快时期（１９８０ —１９９６ 年） 经济发展的主导推动力量和制约因素的研究,目的在于培养可持续农业发展的增长中心,针对性地探讨可持续农业发展的对策。     

边境贸易与口岸增长极系统开发：以新疆为例

本文以新疆为例，论述了边境贸易与周边区域经济增长的密切关系，分析了我国周边地区（以新疆为主）与西亚、南亚、中亚、欧洲等地区贸易的优势、劣势及互补性。在此基础上，提出了口岸增长极系统开发以加强边境贸易的具体建议。