^137Cs法测算黄土高原土壤侵蚀速率的初步研究

核尘埃~(137)Cs降落到地表后,被土壤胶粒强烈吸附,集中分布于0—25cm的土壤表层。土壤剖面的~(137)Cs总量随土壤的流失而减少。根据黄土农耕地和非农耕地土壤的~(137)Cs流失模式,推导了它们的流失量和侵蚀速率的相关公式。根据陕西洛川黑木沟和山西离石羊道沟的13个土壤剖面的~(137)Cs含量测试结果,求得的黑木沟草坡覆盖的老谷坡和新谷坡的侵蚀速率分别为1400 t/km~2·a和5700t/km~2·a;羊道沟梁峁坡农耕地的侵蚀速率为3270—6030 t/km~2·a;裸露新谷坡的侵蚀速率大于8000 t/km~2·a。     

全国固体矿产资源区划数据库建设

为建立全国固体矿产资源成矿远景区划数据库,使全国性资源评价规划工作计算机化,也为在新一轮国家矿产资源潜力评价中引入现代新技术新方法打下重要基础,文章应用GIS技术管理空间数据的有效手段,建立了基于GIS的区划空间数据库,以助于区划地质成果资料的充分、有效利用,开发的数据库可以在新一轮全国成矿远景区划中使用.     

Androzic导航软件在地质灾害调查中的应用

在新的地质领域中,数字化、矢量化技术手段已日益成熟,简捷、高效的技术手段已成为各地质单位所追求的目标。以地质灾害调查为例,通过研究各导航软件的野外离线导入功能,摸索出较为简便、精确的离线地图导入功能:该流程是通过Img2ozf软件转化图片格式为OZF2文件形式;再通过OziExpTrail软件进行离线地图校准,校准个数达4个以上,实际误差为3～5m;最后导入设备Androzic软件中,即可实现离线地图导航。该方法的使用可以有效提高野外地质调查效率,节约纸质资源,减少开支成本,但也存在中文字符文件名无法识别、耗电量大等不足之处,有待后期研究。     

Perturbation of gene expression and steroidogenesis with in vitro exposure of fathead minnow ovaries to ketoconazole

Ketoconazole is a fungicidal drug that inhibits function of cytochrome P450s in the synthesis of steroids. To examine if inhibition of P450 function affects gene expression in a dynamic manner, we conducted in vitro exposures of ovary tissue from fathead minnows (Pimephales promelas) to 0.5 microM ketoconazole to investigate effects on steroid production and gene expression over time. Expression of four key steroidogenesis genes was examined at 1, 6, and 12h of exposure. 11 beta- and 20 beta-hydroxysteroid dehydrogenases were down regulated at 1h and Cytochrome P450 17 was down-regulated at 12h, consistent with the absence of steroid production. In contrast, cytochrome P450 19A was up-regulated at 6h, indicating feedback regulation. Microarray analysis of 12h exposures indicated enrichment of biological processes involved in neurotransmitter secretion, lymphocyte cell activation, sodium ion transport, and embryonic development. These data suggest that, with the exception of cytochrome P450 19A, these steroid metabolic genes are regulated in a feed forward manner and that the effects of ketoconazole may be broader than anticipated based on the mechanism of action alone.     

四川江油马角坝地区石炭纪地层磁化率特征与海平面相对变化研究

马角坝地区是研究四川盆地乃至上扬子地区石炭系沉积特征的经典地区之一.研究马角坝地区石炭系磁化率特征与相对海平面的变化,可为研究相关区域石炭纪沉积特征以及地层划分对比等问题提供依据.本文在四川江油马角坝地区石炭系经典碳酸盐岩剖面连续古地磁采样,共获得179块供测试磁化率的样品,在室内对所有样品进行了磁化率测量与磁化率特征分析,获得了该剖面连续的磁化率数据.利用剖面连续的磁化率变化特征推演海平面相对变化,识别出6次完整的海进-海退记录,由此对研究区石炭系划分出6次海平面变化旋回.     

Why are hatching and emergence success low? Mercury and selenium concentrations in nesting leatherback sea turtles (Dermochelys coriacea) and their young in Florida

Leatherback sea turtles (Dermochelys coriacea) have low hatching and emergence success compared to other sea turtle species. Postmortem examinations of hatchlings showed degeneration of heart and skeletal muscle that was similar to that found in other neonates with selenium deficient mothers. Selenium deficiency can result from elevated concentrations of bodily mercury. Ingested mercury is detoxified by the liver through mercury-selenium compound formation. In animals persistently exposed to mercury, the liver’s ability to detoxify this element may decrease, especially if dietary selenium is insufficient. We measured mercury and selenium concentrations in nesting female leatherbacks and their hatchlings from Florida and compared the levels to hatching and emergence success. Both liver selenium and the liver selenium-to-mercury ratio positively correlated with leatherback hatching and emergence success. This study provides the first evidence for the roles of mercury and selenium in explaining low reproductive success in a globally imperiled species, the leatherback sea turtle.     

Effects of alumina refinery wastewater and signature metal constituents at the upper thermal tolerance of: 2. The early life stages of the coral Acropora tenuis

The success of early life history transitions of the coral Acropora tenuis were used as endpoints to evaluate thermal stress and the effects of wastewater discharged to a tropical marine environment. The studies assessed the effects of: (i) temperature; (ii) three signature metals of the wastewater, aluminium (Al), vanadium (V) and gallium (Ga); and (iii) the wastewater (at 27 °C and 32 °C) on fertilisation and larval metamorphosis. The median inhibition temperatures for fertilisation and metamorphosis were 32.8 °C and 33.0 °C, respectively. Fertilisation IC₅₀s for Al, V and Ga were 2997, 2884 and 3430 μg L⁻¹, respectively. Metamorphosis IC₅₀s for Al, V and Ga were 1945, 675 and 3566 μg L⁻¹, respectively. The wastewater only affected fertilisation and metamorphosis at moderate concentrations (IC₅₀s = 63% and 67%, v/v, respectively, at 27 °C), posing a low risk to this species in the field. The effects of wastewater and temperature on fertilisation and metamorphosis were additive.