基于GIS的通海县烟草种植适应性分析

通海县作为云南烟区高产县之一,烟草的生长情况直接影响着农民收入。以通海县的乡镇小区域为研究单元,通过应用GIS的空间分析技术对影响烟草种植的气候、土壤内的众多因子进行分析并确定各因子的权重加以分析,得出通海县烟草种植区域内最适合种植烟草的区域。不仅提高地区环境综合评价精度,也可以减少农田、化肥等资源的浪费,还可以为烟农的农田规划与烟草种植提供宝贵的科学依据,帮助烟农增产增收。     

攀枝花市雨季开始期的气候分析及其长期预报方法研究

运用攀枝花市气象局提供的市区、仁和区、米易县和盐边县四站历年雨季开始期资料 ,分析了各地雨季开始期的气候特征 ,结合 50 0hPa环流特征指数资料 ,经统计分析 ,建立了预报攀枝花市各县、区的雨季开始期长期预报模式 ,其预报结果令人满意。     

软岩厚度对层状顶板破坏特征影响分析

顶板冒落是煤矿生产的五大灾害之一。顶板冒落主要与顶板岩层性质、赋存状态等因素有关,其中软弱岩层赋存的厚度变化是顶板冒落的主要原因之一。利用东北大学岩石破裂过程分析系统（RFPA2D）,针对煤矿沉积岩层顶板破坏进行力学分析,并对赋存不同厚度软岩的层状顶板的破坏情况进行了数值计算。探讨了不同厚度的软弱岩层对巷道稳定性的影响,得出了不同厚度软弱岩层在巷道开挖后的破坏过程和最后冒落的形状,提出了对不同厚度软弱岩层的层状顶板巷道有针对性的支护措施。该结果对现场施工和试验具有重要的参考价值。     

对舟山渔业经营体制多元化的调查与思考

舟山渔业股份合作制已有20年历史,现已不能完全适应舟山渔业生产力的发展,近期舟山在探讨和实践着新的渔业经营体制。舟山渔业经营体制改革,值得思考的问题有:渔船依法登记;渔民自愿选择经营体制等。     

全球化背景下国际移民社会融合研究综述与展望

21世纪以来,全球化进程加速,国际移民成为研究热点问题,而当前欧美学界针对移民社会融合的研究具有三方面特征：首先,国际移民社会融合的维度呈现多样化;其次,移民社会融合的主动性及其对社区空间的塑造作用成为研究热点;最后,研究视角存在“方法论上的民族主义”和“政治正确的价值倾向”。与之相对,国内学界对国际移民社会融合的研究能够准确地把握国家背景、政治制度、移民政策对移民社会融合的影响作用;以及在全球化背景下国际移民在世界城市快速流动的旅居者特性,且充分注意到移民的多元性和融合的开放性。而不足之处在于,缺少对于社会融合多尺度、多维度的探讨;缺乏对于不同族裔、不同类型的移民群体间社会融合路径、模式、机制的比较。新形势下,国内研究有必要超越西方学者的思考,探讨国际移民社会融合的中国路径,为我国城市解决全球化带来的国际移民融合问题提供新思路。     

Influence of salinity on the early development and biochemical dynamics of a marine fish,Inimicus japonicus

Fertilised eggs of the devil stringer(I nimicus japonicus) were incubated at different salinity levels(21, 25, 29, 33, and 37), and then the hatching performances, morphological parameters, and biochemical composition(protein, lipid and carbohydrate) of the larvae were assayed to determine the influence of salinity on the early development of I. japonicus. The tested salinity levels did not af fect the times of hatching or mouth opening for yolk-sac larvae. However, the salinity significantly influenced the hatching and survival rates of open-mouthed larvae, as well as the morphology of yolk-sac larvae. The data indicated that 30.5 to 37.3 and 24.4 to 29.8 were suitable salinity ranges for the survival of embryos and larvae of I. japonicus, respectively. Larvae incubated at a salinity level of 29 had the greatest full lengths, and decreasing yolk volume was positively correlated with the environmental salinity. With increasing salinity, the individual dry weights of newly hatched larvae or open-mouthed larvae decreased significantly. Newly hatched larvae incubated at a salinity level of 29 had the greatest metabolic substrate contents and gross energy levels, while the openmouthed larvae's greatest values occurred at a salinity level of 25. Larvae incubated in the salinity range of 33 to 37 had the lowest nutritional reserves and energy values. Thus, the I. japonicus yolk-sac larvae acclimated more readily to the lower salinity level than the embryos, and higher salinity levels negatively influenced larval growth and development. In conclusion, the environmental salinity level should be maintained at 29–33 during embryogenesis and at 25–29 during early larval development for this species. Our results can be used to provide optimum aquaculture conditions for the early larval development of I. japonicus.