Changes in zoobenthic community structure after pollution abatement from fish farms in the Archipelago Sea (N. Baltic Sea)

Long-term changes in sediment macrofauna communities at two sites affected by fish farming in the Archipelago Sea, south-west Finland have been investigated. Sampling stations in the S?rk?nsalmi Strait and Kaukolanlahti Bay, previously investigated 1982-1991, were revisited in 1994, 1995 and 1998 to detect signs of recovery following a decrease in organic load since 1990 and 1991, respectively. The results indicate a partial recovery in S?rk?nsalmi during post-pollution years, whereas no improvement has taken place in Kaukolanlahti. The improvement in S?rk?nsalmi is shown by a significant increase in the number of species and total abundance, and by the community structures becoming more similar over time. On the other hand, a significantly decreased number of species, abundance and biomass values over time as well as the occurrence of defaunated anoxic sediments, are clear signs of continued deterioration in Kaukolanlahti. Differences in the recovery potential of the two water areas are interpreted as consequences of topography and water exchange patterns causing differences in oxygen saturation.     

Extended Far-Infrared CO Emission in the OMC-1 Core of Orion

We report the discovery of quasi-periodic oscillations (QPOs) at roughly 187 and 150 Hz in the X-ray intensity of X-ray nova XTE J1859+226. The source was observed during a recent outburst with the Rossi X-Ray Timing Explorer. Besides these high-frequency QPOs, we have also detected QPOs (and sometimes their harmonics) at 6-7 Hz and significant broadband variability at low frequencies. These properties, as well as the observed hard X-ray spectrum, make XTE J1859+226 a black hole candidate (BHC). The detection of QPOs at two distinct frequencies greater, similar100 Hz in two observations separated by about 4 hr provide additional insights into the high-frequency QPO phenomenon in BHCs. The importance lies in the proposed interpretations, which invariably involve the effects of strong gravity near a black hole. We compare our results to those of other BHCs and discuss the impact of the observational data on the models in a global context.     

6Li from Solar Flares

By introducing a hitherto ignored 6Li producing process, due to accelerated 3He reactions with 4He, we show that accelerated particle interactions in solar flares produce much more 6Li than 7Li. By normalizing our calculations to gamma-ray data, we demonstrate that the 6Li produced in solar flares, combined with photospheric 7Li, can account for the recently determined solar wind lithium isotopic ratio, obtained from measurements in lunar soil, provided that the bulk of the flare-produced lithium is evacuated by the solar wind. Further research in this area could provide unique information on a variety of problems, including solar atmospheric transport and mixing, solar convection and the lithium depletion issue, and solar wind and solar particle acceleration.     

奥斯特/GPS掩星与地面雷达联合观测电离层电子密度的初步结果

1999年2月丹麦发射了一颗奥斯特小卫星,它装载了两台GPS接收机,其中一台用于电离层和中性大气掩星测量,另一台用于自主定位。本文给出了1999年10月奥斯特/GPS掩星与日本MU雷达和数字测高仪的联合观测结果。奥斯特掩星反演得到的电子密度剖面与地面雷达观测的进行了比较,结果表明:天基和地基雷达观测的电子密度是一致的。文章还给出利用GPS的单频信号反演电离层电子密度剖面技术和3维射线追踪技术模拟掩星结果。     

矿业与社区:为社会可持续发展而共同努力

针对公司社会责任的政策应如何制定,尤其是矿业方面的政策应如何制定,一直是一个争论不休的问题。作者认为,“学院式的老传统观念”——只从技术和经济的角度看待矿床的开采——早已消亡。矿业公司也必须履行其社会责任。 本文围绕近年来世界范围内的趋势和动态,如:全球化、经济互相依赖和政策权力下放以及民间团体作为一个政治因素的兴起,讨论了矿业的新政策。这些趋势与联合国寻求可持续发展的政策以及过去十年中一些国际会议上所达成的共识一起,提高了全社会的认识,筑起了私营 部门为社会多尽义务的舞台。对社会负责的公司政策包括:将决策权下放到矿区,直到各利益集团和持股人支持政府提供“官方发展援助”,进行有效管理,建立广泛的协作伙伴关系,减少社会曝光。     

地震地面运动的估计问题

感谢地震工程研究会的热情邀请,使我有机会出席为纪念研究会成立50周年而举行的讲演会。     

地下水中铀的反应运移模拟

地下水中铀的反应运移模拟对地下水保护和铀矿区的恢复都很重要, 因为铀是一种化学毒害性很高的放射性元素.在地下水及水与固体之间都应考虑对流、弥散、稀释、吸附等化学相互作用.介绍了德国德累斯顿市附近的Koenigstein矿区淋滤条件的可行性研究结果.由于反应运移模拟需占用大量的CPU时间, 所有的运行在一天内完成, 但用简单的混合法进行了稀释.对于这种研究, PHREEQC 2.2证明是一个功能很强的工具.与PHREEQC相对应的数据库WATEQ4F涉及到48种元素、400多种物质、300多种矿物.根据铀和镭的特性, 对其作了一定的修改, 以使它更具相容性和可靠性.      

Cobalt Deposits in the Central China Orogenic Belt

Cobalt mostly occurs as an associated metal in Cu-Ni sulphide deposits, skarn Fe-Cu-Pb-Zn deposits and volcanic-hosted massive sulphide (VHMS) or sedex deposits. There are different types of cobalt deposits in the Central China orogenic belt. In the Tamu-Kalangu Mississippi-valley type Pb-Zn deposits, many cobalt-nickel sulphide minerals were found. The cobalt content of the ore is 0.064%-0.46% in sedex-type Kendekeke Fe-Pb-Zn-Au deposits, and cobalt sulphide veins with Co contents of 4%-9% have also been found. About 28000 tons of cobalt reserves were delineated in the Dur'ngoi Cu-Co-Zn deposit of VHMS type in the A'nyemaqen Mountains. It is considered that the exploration potential for cobalt is attractive in this district, especially in sedex-type deposits and Co-rich sulphide veins in sedex-type Fe, Cu and Pb-Zn deposits and their surroundings.     

NEOTECTONICS ALONG THE EASTERN MARGIN OF THE TIBETAN PLATEAU: INFERENCES FROM BEDROCK RIVER INCISION PATTERNS

NEOTECTONICS ALONG THE EASTERN MARGIN OF THE TIBETAN PLATEAU: INFERENCES FROM BEDROCK RIVER INCISION PATTERNS1　ChenZ,BurchfielBC ,LiuY ,etal.GPSmeasurementsfromeasternTibetandtheirimplicationsforIndia/Eurasiaintracon tinentaldeformation[J] .JournalofGeophysicalResearch ,2 0 0 0 (inpress) . 2　KingRW ,ShenF ,BurchfielBC ,etal.GeodeticmeasurementofcrustalmotioninsouthwestChina.Geology,1997,2 5,179～ 182 . 3　KirbyE ,WhippleKX ,Burchfie…