Distribution and early life history of <Emphasis Type="Italic">Kaupichthys</Emphasis> leptocephali (family Chlopsidae) in the central Indonesian Seas

Leptocephali of the widely distributed tropical marine eels of the genus Kaupichthys (family Chlopsidae) were collected around Sulawesi Island during a sampling survey in the Indonesian Seas in late September and early October 2002, and the otolith microstructure of 24 of the 59 specimens captured was examined to learn about the larval growth rates and spawning times of these small sized eels. Leptocephali ranging in size from 25 to 60 mm were collected in Makassar Strait and the Celebes Sea, but they were most abundant in the semi-enclosed Tomini Bay of northeast Sulawesi Island. The Kaupichthys leptocephali examined had 39–161 otolith growth increments. Their back-calculated hatching dates indicated that five age groups were present and each group appeared to have been spawned around the full moon of previous months. Average growth rate estimates of the first two age groups were 0.65 and 0.54 mm/day for the 27.4–30.4 and 37.6–45.6 mm age classes. The growth rates of the oldest three age groups (52.0–60.8 mm) appeared to have slowed down after they reached their approximate maximum size. An increase in increment widths at the outer margin of the otoliths of those larger than 53 mm suggested that the process of metamorphosis had begun even though there were few external morphological changes indicating metamorphosis. It is hypothesized that chlopsid leptocephali have an unusually short gut that may not need to move forward during early metamorphosis. The presence of four age classes in Tomini Bay suggests that the Togian Islands region may be productive habitats for Kaupichthys juveniles and adults.     

云南粳稻核心种质杂种后代孕穗期耐冷性研究

以236份云南地方粳稻核心种质和云南主栽梗稻Oryza satica品种合系35配制的杂种F5、BC1F4、BC2F3和BC3F2为材料,在昆明自然低温平均17.8℃(冷害)条件下,对亲本及其后代进行孕穗期耐冷性研究.结果表明:①亲本耐冷性状间的相关性明显高于其杂种后代,不同世代间总体趋势为随着回交世代增加其性状间相关性减弱.在亲本及其杂种后代间耐冷指标性状穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率均呈较高的(≥0.370)极显著(n=236,R0.01=0.181)相关.②株高、穗颈长、穗下节长等耐冷性状在亲本强弱耐冷系统群间的差异明显,表现为亲本耐冷性强的材料秆和穗较长、穗粒数较多,同一性状变异程度减小.但随着回交代数的增加,这些性状的平均值逐渐趋同于轮回亲本,差异减小.③穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率在5个稻作区间的变化规律呈现一致性,亲本和F5的差异较大,而BC2F4、BC2F3和BC3F2的差异较小,且趋同于轮回亲本.通过连续回交,在BC3F1即可获得耐冷性状表现良好的材料.     

不同土地利用方式下土壤粒径分布的分维特征

西安市临潼区杏园、桑园和农田土壤粒径分布的体积分形维数分析结果表明:(1)杏园和农田土壤颗粒的体积分形维数与＜0.002 mm和0.002～0.05 mm颗粒含量呈极显著正相关关系,与0.05～0.1 mm、0.1～0.25 mm颗粒含量呈极显著负相关关系,与0.25～0.5 mm颗粒含量不相关.桑园土壤颗粒的体积分形维数与＜0.002 mm和0 002～0.05 mm颗粒含量呈极显著正相关关系,与0.05～0.1 mm、0.1～0.25 mm和0.25～0.5 mm颗粒含量不相关.(2)桑园和杏园土壤颗粒体积分形维数与土壤有机质含量和pH值复相关达显著水平,而农田土壤颗粒体积分形维数与土壤有机质含量和pH值复相关不显著.     

辽河油田石油污染土壤的2阶段生物修复

建立了污染土壤预制床处理工程,对不同类型原油污染土壤分别进行堆腐处理,历时2个阶段,共运行210d.当稀油、稠油、特稠油和高凝油污染土壤中石油烃总量(TPH)为25.8～77.2g·kg^-1时,经过53d(为第1阶段)的运行,TPH去除率38.37%～56.74%.第2年(为第2阶段)继续处理156d,TPH降解率达到66.59%～80.96%.连续运行结果表明,污染土壤中易分解的石油烃污染物大部分在第1阶段得到降解,第二阶段降解率明显降低.     

巯基化合物在万寿菊镉解毒中的作用

采用水培实验方法研究了万寿菊体内镉积累和解毒与巯基化合物含量的关系。万寿菊植株分别在镉浓度为0、0.1、0.5、2和8 mg/L的营养液中暴露7 d,测定了根、茎、叶中镉、非蛋白巯基(NPT)、半胱氨酸(Cys)、γ-谷氨酰半胱氨酸(γ-EC)、谷胱甘肽(GSH)和植物络合素(PCs)的含量。植物根、茎、叶中镉含量都随着镉暴露浓度的增加而增加。当溶液中镉浓度较低(0.1～2 mg/L)时,茎叶中NPT、PCs、Cys和γ-EC含量随着镉浓度增加而增大;当镉浓度较高(8 mg/L)时,茎叶中PCs含量迅速降低,GSH含量大幅度增高。在根部,这些巯基化合物的含量几乎不受镉处理影响,且含量较低。以上研究结果表明:PCs在万寿菊镉的解毒机制中发挥一定的作用,暴露于高浓度的镉,GSH比PCs起着更为重要的解毒作用。     

内循环三相生物流化床处理生活污水的试验研究

对内循环三相生物流化床处理生活污水进行了试验研究,探讨了生物膜的形成和水力停留时间及曝气量对处理效果的影响。结果表明：在HRT为6h,曝气量为0.6m3/h,进水COD和NH4＋-N分别为240.2~298.7mg/L和29.1~68.9mg/L条件下,平均COD去除率为83%,NH4＋-N去除率为95.1%。     

北京市大气PM2.5中矿物成分的污染特征

为了解北京市大气细粒子中矿物成分的浓度水平和污染特征,在清华园和车公庄进行了连续1a的PM_2.5累积周采样和全样品分析.Al、Si、Ca、Mg和Fe等地壳元素的周变化相似,最大周均浓度均出现在春季有强沙尘天气的一周;其季节变化显著,显示季节性的源排放以及气象条件对矿物成分的含量影响显著.土壤尘的季节平均浓度从夏季逐步上升,至次年春季达到最高(21.1 μg·m^-3),表明春季频繁发生的沙尘天气对土壤尘细粒子有重要贡献.大量的建筑活动可能大大增加了北京细粒子中Ca的负荷,应加强其排放控制.     

江西西华山钨矿床流体包裹体特征及成矿流体来源

本文对江西西华山钨矿床的石英流体包裹体进行了岩相学和显微测温分析,研究了石英流体包裹体的气、液相组分及碳、氢、氧同位素特征。结果表明,石英中流体包裹体十分发育,包裹体类型有NaCl-H2O(盐水)包裹体(Ⅰ)和CO2-H2O包裹体(Ⅱ),且以前者为主。包裹体均一温度在200℃～280℃,平均249.5℃;盐度为7.89%～13.95%,平均10.73%;成矿流体密度为0.628g/cm3～0.895g/cm3,平均0.795g/cm3,属低盐度低密度范畴;压力平均值为64.01MPa,对应的成矿深度平均值为6.45km。成矿热液气相成分以H2O为主,CO2含量低;液相成分阴阳离子浓度都很低,相对富钠和氯,流体离子类型大致呈Na+-K+-Cl--SO42-型。成矿流体基本来自岩浆水,部分可能有变质水的加入;流体中碳主要由岩浆水提供,少数由地幔源提供。     

Dust Storms are an Indication of an Unhealthy Environment in East Asia

Dust storms frequently occur in Mongolia and in northern China. Each year there are 30 to 120 dusty days in source regions of Mongolia and 14–20 dusty days on the Korean Peninsula. Intense sand storms and associated dust falls produce environmental impacts in East Asia. This paper discusses the environmental degradation in Mongolia and the social, economic and atmospheric impacts of dust storms in the sink area. The impact of dust storms on environmental compartments as well as their direct and indirect consequences to basic resources like water and energy demand and supply is explained. Governments are encouraged to take appropriate action in specified regions. For monitoring dust storms there is a need for international cooperation to combat growing environmental and human security concerns.     

First-trimester screening for Down syndrome; the role of nasal bone assessment in the Korean population

Objectives The aim of this study was to evaluate the role of nasal bone assessment in first-trimester screening for Down syndrome (DS) in the Korean population. Methods From July 2004 to March 2006, we prospectively evaluated the fetal nasal bones at 11–14 weeks' gestation in the Korean population. Results A successful evaluation was possible in 6490 of 6787 fetuses (95.6%). Absent, hypoechoic, and short nasal bones were seen in 4 (26.7%), 4 (26.7%), and 1 (6.7%) of 15 fetuses with DS, respectively, whereas in 5 (0.1%), 11 (0.2%), and 246 (3.8%) of 6456 normal fetuses. The incidence of absent and hypoechoic nasal bone showed significant differences between normal fetuses and fetuses with DS (P < 0.0005, both). Screening for DS using an absent or hypoechoic nasal bone resulted in a sensitivity of 53.3%, a specificity of 99.8%, a positive likelihood ratio of 215.2, and a negative likelihood ratio of 0.5. Conclusion Our study showed that nasal bone abnormality at 11–14 weeks of gestation had a high association with DS in the Korean population. This suggests that nasal bone assessment can be used to supplement the current first-trimester screening for DS in the Korean population. Copyright © 2007 John Wiley & Sons, Ltd.