Effects of two sediment types on the fluorescence yield of two Hawaiian scleractinian corals

This study used non-invasive pulse-amplitude modulated (PAM) fluorometry to measure the maximum fluorescence yield (F(v)/F(m)) of two Hawaiian scleractinian coral species exposed to short-term sedimentation stress. Beach sand or harbor mud was applied to coral fragments in a flow-through aquarium system for 0-45 h, and changes in F(v)/F(m) were measured as a function of sediment type and length of exposure. Corals were monitored for up to 90 h to document recovery after sediment removal. Sediment deposition significantly decreased F(v)/F(m) in both species and was a function of sediment type and time. Corals that received sediment for 30 h or more had the greatest reduction in yield and exhibited little recovery over the course of the experiment. Harbor mud caused a greater reduction in Porites lobata yield than beach sand, whereas both sediment types had equally deleterious effects on Montipora capitata. Colony morphology and sediment type were important factors in determining yield reduction--P. lobata minimized damage from coarse sand grains by passive sediment rejection or accumulation in depressions in the skeleton, and fluorescence yield decreased most in corals exposed to sticky harbor mud or in colonies with flattened morphologies. Species-specific differences could not be tested due to differences in colony morphology and surface area.     

浙江龙游县虎头山是否存在"金伯利岩"

据1998年两报刊报道，浙江龙游虎头山发现一粒1／5米粒大小的金刚石，并确认含该金刚石的岩石为金伯利岩。笔者根据该岩体岩石性质、岩全产状、岩石化学成分、特征矿物组合等待征，初步推断该岩石为角砾状超基性岩，原岩恢复为橄辉云煌岩，而不是金伯利岩，也不是钾镁煌斑岩。     

简评VAN地震预报方法

评估一种地震预报方法预报准确与否的标准，不应仅仅依赖于应用抽象而严格的统计定律的方法，而忽视的地震现象的具体特点。断层破裂过程与掷股子不能相拼并论的。本文的结论是如何我们采用Ｍｕｌａｒｇｉａ，Ｇａｓｐｅｒｉｎｉ（１９９２）在评估ＶＡＮ方法时所提出的方法，那么，即使是一种理想的地震方法，也会在前兆和震间表现出某种“不确定”的联系，每次ＶＡＮ预报需单独评估，同时必须考虑所有具体情况和信息，震中位置预报     

加拿大安大略州瓦瓦附近的太古宙奥长花岗岩中的含金石英脉的气液包裹体和蚀变模式

在安大略的瓦瓦北东80公里处的1.6公里的瓦瓦绿岩带内,太古宙花岗质岩石中出露含金石英脉体系。雷纳比(Renabie)矿区含金石英脉向西延伸约850米,陡倾,从地表向下延伸至少达950米深处。矿体围岩达30米宽、210米长。布朗米库(Braminco)的六条含金石英脉走向从北到北西向,陡倾,脉宽达20米。长石被蚀变形成石英+方解     

中元古界纳尔逊山组的古地磁:科迪勒拉的晚前寒武纪区域再磁化事件的证据

从不列颠哥伦比亚东南普赛尔(Purcell)山脉的纳尔逊山(Mount Nelson)组(普赛尔超群顶部)所采的92块化学退磁和热退磁标本,具有二组明显的定向群。发现于热退磁和化学退磁期间的MN—A方向,具D=274°,I=19°(a95=10°,已倾斜校正)的平均方向,这与156°E,1O°N的磁极位置相符。MN—A存在于细粒亦铁矿中,并具与国立冰川公园一克拉克山脉地区的贝尔特-普赛尔(Belt—Purell)超群中上部所报道的其它     

地球内核的旋转和磁性

地球发电机三维数值模拟说明,地球固内核相对于地幔的超（速）旋转是由内核和液体外核内的东向热风之间的耦合来维持的。这种机制类似于同步电动机的机制,在地球磁场的产生中也起着重要作用。