Ocean floor spreading: olduvai and gilsa events in the matuyama epoch

The magnetic anomaly usually associated with the Olduvai geomagnetic event (1.96 million years) should probably be associated with the Gilsa event (~ 1.65 million years). The Oldu-vai event can be correlated with a con-sistently appearing minor anomalycalled W. This reassignment gives near-ly uniform spreading rates for sections of the mid-ocean ridge system consid-ere( l here.     

Ridge spreading, subduction, and sea level fluctuations

A numerical model of mantle convection shows that sea level fluctuations are not simply associated with temporal changes in ocean c plate spreading. In the dynamic model, sea level rises rapidly and then falls toward a steady value (but one still higher than the initial) following increased ridge spreading; this time dependence results from profound changes in the deep thermal structure under ocean and continent. The use of past variations in oceanic spreading to infer sea level fluctuations is called into question. With more realistic models and better continental stratigraphy, constraints may be placed on the viscosity structure of the mantle.     

Fish, crustaceans, and the sea floor under the ross ice shelf

Baited traps and a camera lowered through the Ross Ice Shelf, Antarctica, at a point 475 kilometers from the open Ross Sea and to 597 meters below sea level revealed the presence of fish, many amphipods, and one isopod. Biological or current markings were not evident on a soft bottom littered with subangular lumps. A fish was caught through a crevasse 80 kilometers from the shelf edge.     

Sea-floor spreading, carbonate dissolution level, and the nature of horizon a

Evidence from leg 2 of the Deep Sea Drilling Project suggests a constant spreading rate for the floor of the North Atlantic over the past 80 million years; a major lowering of the carbonate dissolution level during the early Pliocene; and an early to middle Eocene age for horizon A.     

我国黄东海区海洋捕捞现状·问题与对策研究

我国海洋捕捞业发展迅速,为推进我国"蓝色粮仓"建设起到了重要作用,然而,随着一系列资源环境问题的不断涌现,我国海洋捕捞业的可持续发展形势日益严峻。黄东海是我国重要的渔业产区,在我国海洋捕捞业中占据着十分重要的地位。近些年来,黄东海区海洋捕捞产量占全国的比重不断增大,海洋捕捞总产值逐年增加,但作业范围大多仍局限于海洋捕捞资源过度利用的近海区域,海洋渔业资源日渐衰竭、海洋渔政管理困难,过度捕捞禁而不止,近海海域环境不断恶化等问题已不容忽视。在以资源节约、环境友好为重要准则的现代海洋渔业战略背景下,从调整产业结构,发展远洋捕捞、完善立法,加强渔政管理、大力发展海水养殖业,减轻捕捞压力、加强环境保护等方面出发采取有力措施,促进黄东海区海洋捕捞可持续发展。     

Tectonics and volcanism of eastern aphrodite terra, venus: no subduction, no spreading

Eastern Aphrodite Terra, a deformed region with high topographic relief on Venus, has been interpreted as analogous to a terrestrial extensional or convergent plate boundary. However, analysis of geological and structural relations indicates that the tectonics of eastern Aphrodite Terra is dominated by blistering of the crust by magma diapirs. The findings imply that, within this region, vertical tectonism dominates over horizontal tectonism and, consequently, that this region is neither a divergent nor a convergent plate boundary.     

Disaster, Catastrophe, and Local Persistence of the Sea Palm Postelsia palmaeformis

Two components of natural disturbance, its local intensity and frequency beyond a threshold level, limit a marine benthic alga to wave-swept shores. Transplant experiments indicate that the limited distribution is not due to physiological restriction. Instead, it requires predictable annual disturbance of moderate intensity for local persistence.     

学习的风格和策略与第二语言听力教学

主要论述学习者因素中的学习风格因素对将英语作为第二语言的学生听力理解的影响,以及针对学生的学习风格所进行的相应听力理解策略训练。主要采用调查问卷的研究形式,对影响学生听力理解的诸因素进行调查。研究发现,大多数被调查学生属于串珠式的学习风格,在听力理解过程中对词汇的依赖性很强。针对这种情况应训练学生使用以句法为感知单位的、自上而下的听力策略,从而更加有效地提高他们的听力理解能力。     

Mid-atlantic ridge: age and spreading rates

Fission-track dating of basaltic glass from the Mid-Atlantic Ridge gives results which are consistent with the proposal of ocean-floor spreading. Solidification ages from ~10,000 years to ~300,000 years were measured. Correlation is also possible between the magnetic anomaly patterns over the Crest Mountains at 45 degrees N and the geochronology of the outcropping basalts. Renewed volcanic activity well removed from the axis of the Mid-Atlantic Ridge has been demonstrated to have taken place in recent times.     

黄、渤海的软骨鱼类种类及利用价值

介绍了黄、渤海所产38种软骨鱼类的分类地位、中文名、学名、主要特性及其利用价值，并着重综述了对软骨鱼类药用价值的研究成果。     

The viscous sublayer at the sea floor

A 0.6-centimeter-thick sublayer was found in horizontal flow profiles obtained by traversing a heated thermistor from 19 centimeters above to 2 centimeters below the water-sediment interface in 200-meter-deep water on the Oregon continental shelf. In this sublayer the speed of the current varies linearly with distance above the sediment. Estimates of viscous stress from this sublayer and turbulent stress from the profile agree within 5 percent. Stress calculated from a current-meter spectrum agrees within its 95 percent confidence limits.     

Indoor airborne asbestos pollution: from the ceiling and the floor

Electron microscopic measurements of the concentrations of airborne asbestos were carried out inside and outside an office building having ceilings sprayed with a crocidolite-containing material and floors covered with vinyl-chrysotile tiles. Under normal conditions in this building, constructed 10 years ago, the two asbestos-containing materials released fibers into the air. This is the first measurement of elevated (up to 170 nanograms per cubic meter) concentrations of indoor airborne asbestos associated with the weathering of asbestos floor tiles during their service life. Asbestos flooring is used in a large number of buildings and represents the third largest use of asbestos fibers in the United States and in Europe, ranking after roofing and asbestos-cement pipe.