Characteristics of nitrogen forms in the southern Huanghai Sea surface sediments

The distributions of different forms of nitrogen in the surface sediments of the southern Huanghai Sea are different and affected by various factors. The contents of IEF-N, SOEF-N and TN gradually decrease eastward, and those of SAEF-N northward, while those of WAEF-N westward. Around the seaport of the old Huanghe (Yellow) River, the contents of both SOEF-N and TN are the highest. Among all the factors, the content of fine sediment is the predominant factor to affect the distributions of different forms of nitrogen. The contents of IEF-N, SOEF-N, and TN have visibly positive correlation with the content of fine sediments, and the correlative coefficient is 0.68, 0.58 and 0.71 respectively, showing that the contents of the three forms of nitrogen increase with those of fine sediments. The content of WAEF-N is related to that of fine sediments to a certain extent, with a correlative coefficient of 0.35; while the content of SAEF-N is not related to that of fine sediments, showing that the content of SAEF-N is not controlled by fine grain-size fractions of sediments. In addition, the distributions of different forms of nitrogen are also interacted one another, and the contents of IEF-N and SOEF-N are obviously affected by TN, while those of inorganic nitrogen (WAEF-N, SAEF-N and IEF-N) are not affected by SOEF-N and TN obviously, although they are interacted each other.

青海湖鸟岛地区植物群落物种多样性与土壤环境因子的关系

生物多样性是测度生态系统内物种组成、结构多样性和复杂化程度的客观指标,是生态系统内生物群落对生物和非生物环境综合作用的外在反映.生物多样性研究已经成为当今植物生态学研究的热点之一[2,3,6,7,1],对于具体的植物群落来说,大的气候条件相对一致,群落生境的差异可能是形成物种多样性的主要原因,而土壤因子可能是一个重要的环境因子,因此,研究物种多样性与土壤环境的关系有重要的意义,国内外都对此做了大量的研究[3,5,10,17].利用数学方法研究鸟岛地区物种多样性与土壤环境的关系,一方面可以进一步了解这一片新生土地的特点,增加高海拔地区的资料,另一方面可以为保护鸟岛这一青海湖物种多样性关键地区提供理论支持.

汶川地震后青少年创伤后应激障碍症状及其相关因素研究

The present paper studies focus on the symptoms of the post-traumatic stress disorder in adolescents post-disaster. 482 students from 6 secondary schools and 17 primary schools in the extremely severe disaster areas in Mianzhu, Sichuan province and 785 students from 3 primary schools and 9 secondary schools in the severe disaster areas in Baoji, Shaanxi respectively were surveyed on the symptoms of the post-traumatic stress disorder and the extent of disaster exposure after the Wenchuan earthquake. Self-compiled background information questionnaire and CRIES were used for the investigation. In this study, we contrast the extent of disaster exposure in the two areas in order to explore the related factors about the post-traumatic stress disorder in adolescent post-disaster. The main results of this paper can be summarized as follows： 1. There are significant positive corrections between the post-traumatic stress disorder and the extent of disaster exposure(get trapped in the earthquake、relatives and friends have been injured in the earthquake、look at relatives and friends dying in the earthquake).The more exposed in the disaster, the more serious symptom of the post-traumatic stress disorder. The trauma exposure indicators (get trapped in the earthquake, relatives and friends have been injured in the earthquake、look at relatives and friends dying in the earthquake)were all significant predictors for PTSD severity. 2. There are significant sex difference in the extent（F=8.750, p <0.05） and the incidence rate of PTSD（χ =20.735, df=5,p =0.001）, the extent and the incidence rate of girls in Mianzhu is significantly higher than that of boys. 3. The age is also an influence factor of PTSD. The extent （F=7.246, p <0.001）and the incidence rate （χ =20.735, df=5,p =0.001）of PTSD get higher as adolescent in Mianzhu get older. 4. As the extremely severe disaster areas, the extent of disaster exposure of Mianzhu areas significantly higher than that of the severe disaster areas Baoji. However, there are not difference in the extent of PTSD between two areas（t=0.181，df=1265,p=0.857）, there are only significant difference in the incidence rate of PTSD between two areas（χ =8.766，df=1,p=0.003）, the incidence rate of PTSD in Mianzhu areas significantly higher than that of Baoji areas.