酸化过程对不同碳酸钙含量的海洋沉积物中总氮及其同位素分析的影响

为节约成本和样品,一些学者同时分析海洋沉积物中的碳、氮及其同位素（TOC、TN、δ¹³C和δ¹⁵N）。分析沉积物中的δ¹³C,需要对样品进行酸化去除无机碳,但是这一酸化过程会使TN和δ¹⁵N的分析结果产生偏差,且偏差范围与沉积物中无机碳含量（CaCO₃）有关。本研究选取了低CaCO₃含量（1-16%）和高CaCO₃含量（20-40%）的海洋沉积物样品,比较了酸化过程对TN和δ¹⁵N的影响。研究结果表明,酸化过程对海洋沉积物中TN和δ¹⁵N的分析结果产生了显著影响。对于低CaCO₃含量的样品,酸化导致样品中TN流失了约0-40%,δ¹⁵N偏移了约0-2‰;而对于高CaCO₃含量的样品,酸化导致样品中TN流失了约10-60%,δ¹⁵N偏移了约1-14‰。表明酸化对TN和δ¹⁵N的影响已经超过了仪器的误差范围0.002%（TN）和0.08‰（δ¹⁵N）,将影响TN和δ¹⁵N的环境指示意义。因此,即使海洋沉积物样品中CaCO₃含量很低,也必须用原样分析TN和δ¹⁵N以避免酸化过程的影响。     

基于面板数据的我国海洋渔业经济的影响因素

本研究选取海洋渔业固定资产投资额、海洋渔业劳动力数量、海洋捕捞生产率和海水养殖生产率4个变量,提出影响因素假设;选取我国沿海地区海洋渔业的面板数据,进行模型设定和数据检验。通过确定变截距固定效应的回归模型形式,对模型进行估计和分析,结果表明:海洋渔业固定资产投资额、海洋渔业劳动力数量和海水养殖生产率与海洋渔业经济呈正相关,影响度由大到小依次为劳动力因素、资本因素和生产率因素,而海洋捕捞生产率的影响基本不显著;各地区海洋渔业经济发展程度不一,且差距明显。在此基础上,提出促进我国海洋渔业经济发展的对策建议:加强专业人才集聚;提高资本投入,完善资本市场建设;提高海水养殖生产率,数量和品质兼备;推动区域一体化联动发展。     

Cenozoic Magmatism of the North-Eastern Eurasian Margin: The Role of Lithosphere Versus Asthenosphere

Sikhote-Alin and Sakhalin are located in the Russian Far Eastflank of the northernmost part of the Sea of Japan. Magmatismin this region preceded, was concurrent with, and continuedafter the extension and sea-floor spreading (25–18 Ma)that formed the Sea of Japan. Among the Sikhote-Alin and Sakhalinvolcanic suites, Eocene–Oligocene (55–24 Ma) lavasare characterized by greater large ion lithophile element andrare earth element enrichments compared with Early–Mid-Miocene(23–15 Ma) tholeiites, and also show a depletion in highfield strength elements (HFSE). The geochemical characteristicsof the Eocene–Oligocene and Early–Mid-Miocene basaltsare consistent with migration of the locus of magma generationbeneath the Sikhote-Alin and Sakhalin areas from subduction-modifiedlithospheric mantle into mid-ocean ridge basalt (MORB)-sourceasthenosphere as spreading in the Sea of Japan progressed. Mid-Miocene–Pliocene(14–5 Ma) lavas, erupted following the opening of theSea of Japan, include alkaline and sub-alkaline basalts withwide ranges in trace-element abundances, varying between twodistinct end-members: (1) volumetrically minor alkaline basaltswith Zr–Nb and Sr–Nb–Pb isotope compositionssimilar to asthenosphere-derived, intra-plate–hotspotbasalts from eastern China; (2) more abundant, lithosphere-derived,low-alkali tholeiites depleted in HFSE. The similarity of isotopicsignatures coupled with systematically different rare earthelement (REE) abundances in the Mid-Miocene–Pliocene andChinese basalts are best modeled by similar extents of meltingof spinel lherzolite and garnet lherzolite, respectively. TheMid-Miocene–Pliocene alkali basalts were generated bysmall degrees of partial melting of hot asthenosphere beneatha thin lithospheric lid; the thin lithospheric mantle beneaththe Sikhote-Alin and Sakhalin region resulted from heating andextension associated with the opening of the Sea of Japan. KEY WORDS: north-eastern Eurasian margin; Sikhote-Alin–Sakhalin; Japan Sea opening; subcontinental lithosphere; asthenosphere     

Seasonal and global NOx production by lightning estimated from the Optical Transient Detector (OTD)

The Optical Transient Detector (OTD) lightning data for the 12‐month period of 1996 are used to estimate the seasonal and global distributions of lightning‐produced NO _x . The relatively small viewing footprint and the low detection efficiency of the OTD sensor and other difficulties require extrapolations of the OTD data to the actual global flash distributions. Furthermore, available measurements for the ratios of intracloud (IC) to cloud‐to‐ground (CG) flashes have been used to partition lightning counts for IC versus CG flashes from the OTD observations. The resulting lightning distributions are then used to calculate the global and seasonal production of NO _x , assuming a NO production rate of 6.2×10²⁵ molecules for each CG flash and 8.7×10²⁴ molecules for each IC flash. Consequently, we find that CG flashes produce more NO _x than IC flashes despite fewer CG flashes by a factor of 3 or more. NO _x production by lightning varies seasonally in accordance with the global lightning distribution, with the maximum production occurring in the Northern Hemisphere in the local summer. The latitudinal distribution of NO _x production exhibits a strong seasonal variation outside the tropics with the production occurring mainly in the summer hemisphere, whereas in the tropics the production is high throughout the year. The annual contribution to NO _x production by lightning is higher in the Northern Hemisphere than that in the Southern Hemisphere.     

不同温度下罗非鱼人工感染海豚链球菌后血液生化指标及组织病理

在28℃、33℃两种温度下,用海豚链球菌人工感染尼罗罗非鱼后,测定尼罗罗非鱼血液生化指标。结果显示:两个温度水平病鱼的血清总蛋白(TP)随时间延长都呈现升高趋势;谷丙转氨酶(ALT)、谷草转氨酶(AST)活性随时间延长先升高后降低再升高,33℃实验组ALT、AST活性比28℃实验组达峰值时间短,并显著高于对照组(p<0.05);尿素、钾(K+)含量随时间延长逐渐升高后降低,钠(Na+)含量先升高后降低再升高,肌酐含量呈上升趋势;血清碱性磷酸酶(AKP)活性28℃实验组呈先升高后降低趋势,33℃实验组呈升高趋势;超氧化歧化酶(SOD)活性随时间延长先升高后降低再升高,33℃实验组各个时间点基本高于28℃实验组;球蛋白(GLO)随感染后时间延长呈现升高趋势,至120 h,显著高于对照组(p<0.05),但温度组间各时间点没有显著差异(p>0.05)。组织病理学观察发现,33℃实验组肝细胞、肾小管上皮细胞水肿变性;28℃实验组肝细胞出现嗜酸性小体;肾小管上皮细胞出现嗜酸性的红色小体,颗粒变性。表明感染海豚链球菌的尼罗罗非鱼肝脏、肾脏均有损伤,造成功能障碍,高温时损伤更严重。     

基于比值法的多源多时相数据城区变化检测

针对中、低分辨率影像采用常规分类方法进行变化检测无法取得理想效果的问题,本文提出了一种基于比值法的雷达数据和光学影像相结合的城市变化检测方法。该方法综合雷达数据和光学影像的优势,以赣州定南县为研究对象,首先利用比值法分别对两种数据源进行城市变化检测,然后通过分析城区地物目标散射特性,对多个时相变化情况进行真彩色合成,最后结合城市建设规划进行分析验证,从而完成城市实时动态变化检测。试验结果表明,利用多源多时相数据进行比值法可成功地提取出试验区域的变化信息,在城区建筑变化检测中,纹理信息更清晰,准确性更高。