Book reviews     

David M. Nelson  William Berry Lyons  Victor S. Kennedy  Richard Dame 《Estuaries and Coasts》1982,5(4):325-327

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Production and pelagic dissolution of biogenic silica in the Southern Ocean     

David M. Nelson  Louis I. Gordon 《Geochimica et cosmochimica acta》1982,46(4):491-501

Vertical distributions of particulate silica, and of production and dissolution rates of biogenic silica, were determined on two N-S transects across the Pacific sector of the Antarctic Circumpolar Current during the austral spring of 1978. Particulate silica profiles showed elevated levels in surface water and near the bottom, with low (35–110 nmol Si · 1^?1) and vertically uniform values through the intervening water column. Both the particulate silica content of the upper 200 m and the production rate of biogenic silica in the photic zone increased from north to south, reaching their highest values near the edge of the receding pack ice. A significant, but variable, fraction (18–58%) of the biogenic silica produced in the surface layer was redissolving in the upper 90–98 m. Net production of biogenic silica in the surface layer (production minus dissolution) was proceeding at a mean rate of ca. 2 mmol Si · m^?2 · day^?1. This is ca. 4 times greater than the most recent estimate of the mean accumulation rate of siliceous sediments beneath the ACC. We estimate, based on mass balance, that the mean dissolution rate of biogenic silica in subsurface water column in the Southern Ocean is 1.2–2.9 mmol Si · m^?2 · day^?1.  相似文献   

Isotopenmethoden in der hydrologie: H. Moser and W. Rauert, 1980, Gebrüder Borntraeger,Berlin-Stuttgart, 400 p., DM 138     

P. Fritz 《Geochimica et cosmochimica acta》1982,46(2):304

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Difference of Ti,Zr, Y and P content in calc-alkaline andesites from island arcs and continental margin (Central Andes)     

Carlos M. Palacios  Nelson S. Guerra  Patricio B. Campano 《International Journal of Earth Sciences》1983,72(2):733-738

Ti, Zr, Y and P, known to be chemically immobile elements during alteration and metamorphism, have been ploted in a set of diagrams in order to discriminative between calc-alkaline andesites from island arcs and continental margin. This method may be an appropiate procedure to help in the discrimination between ancient volcanics of both groups.  相似文献   

Polycyclic aromatic hydrocarbons and their molecular diagnostic ratios in urban atmospheric respirable particulate matter   总被引：2，自引：5，他引：2  

María del Rosario Sienra  Nelson G. Rosazza  Margarita Prndez 《Atmospheric Research》2005,75(4):267-281

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Santiago de Chile city were evaluated to study particulate PAHs profiles during cold and spring weather periods. Urban atmospheric particulate matter PM10 was collected using High Volume PM10 samplers. Fifteen samples of 24 h during austral winter and 20 samples of 24 h during spring, 2000 were collected at two sampling sites (North–East and Central areas of the city) whose characteristics were representative of the prevailing conditions. Seventeen PAHs were quantified and total PAHs concentration ranged from 1.39 to 59.98 ng m⁻³, with a seasonal variation (winter vs. spring ratio) from 0.5 to 12.6 ng m⁻³. Molecular diagnostic ratios were used to characterize and identify PAHs emission sources such as combustion and biogenic emissions. Results showed that the major sources of respirable organic aerosol PM10 in Santiago are mobile and stationary ones.  相似文献   

Slip rates variability and sediment mobilization on a shallow landslide in the northern Swiss Alps     

Marco Schwab  Christine Läderach  Dirk Rieke-Zapp  Fritz Schlunegger 《Swiss Journal of Geoscience》2007,100(2):281-292

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Impact of highly permeable sediment units with inclined bedding on solute transport in aquifers     

Fritz Stauffer 《Advances in water resources》2007

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Post-earthquake investigation on several geosynthetic-reinforced soil retaining walls and slopes during the Ji-Ji earthquake of Taiwan   总被引：1，自引：0，他引：1  

Hoe I. Ling  Dov Leshchinsky  Nelson N. S. Chou 《Soil Dynamics and Earthquake Engineering》2001,21(4):3087

This paper gives an overview on the application of geosynthetic-reinforced soil structures in Taiwan. Taiwan has an unique topography and geotechnical conditions that rendered a less conservative and more challenging design compared to that of North America, Europe and Japan. The Ji-Ji (Chi-Chi) earthquake of 1999 gave an opportunity to examine the behavior of reinforced soil structures. The performance of several modular-block reinforced soil retaining walls and reinforced slopes at the vicinity of the fault was evaluated. Reinforced structures performed better than unreinforced soil retaining walls. The failure cases were highlighted and the cause of failure was identified. The lack of seismic design consideration could be a major cause of failure. The compound failure mode, the inertia force of the blocks, and the connection stiffness and strength relative to the large dynamic earth pressure, were among major items that would warrant further design consideration.  相似文献   

Social network interactions among mentally ill persons in community housing: research issues and agenda     

Dr. G. B. Hall  Dr. G. B. Nelson  Dr. D. Squire  Prof. Dr. R. Walsh 《GeoJournal》1992,26(1):81-86

This paper discusses social network interactions among individuals who have been hospitalized with mental illness and who currently reside in different types of community housing programmes. First, a conceptualisation of social networks that focuses on network interactions, both supportive and non-supportive, between network interactions may be more important influences on successful or unsuccessful adaptation of current and former psychiatric patients to community life than the structural dimensions of social networks more commonly analysed in the literature. The design of a current longitudinal study of social network interactions is presented. The results of two pilot studies that examine social network interactions is presented. The results of two pilot studies that examine social network interactions with data from several community housing programmes in southern Ontario, Canada are reviewed and an agenda is stated for further data collection and analysis.  相似文献   

A skeletal assemblage classification system for non-tropical carbonate deposits based on New Zealand Cenozoic limestones     

Shaun Hayton  Campbell S. Nelson  Steven D. Hood 《Sedimentary Geology》1995,100(1-4)

Cenozoic limestones in New Zealand are mainly skeletal grainstones and packstones formed under non-tropical climatic conditions in open marine shelf or ramp environments. Following petrographic analysis of the nature and abundance of the skeletal components in nearly 500 samples of these limestones, a complete linkage cluster analysis identified seven major skeletal assemblages that may be regarded as subdivisions of the single foramol skeletal association defined by Lees and Buller (1972) for temperate-region carbonate deposits. The seven assemblages are given contracted names, as follows: (a) BARNAMOL = barnacle/bivalve-dominated; (b) BIMOL = bivalve-dominated; (c) BRYOMOL = bryozoan/bivalve-dominated; (d) ECHINOFOR = echinoderm/benthic foraminiferal-dominated; (e) NANNOFOR = nannofossil/planktonic foraminiferal-dominated; (f) RHODALGAL = calcareous red algal-dominated; and (g) RHODECHFOR = calcareous red algal/echinoderm/benthic foraminiferal-dominated. A composite triangular classification diagram has been devised for naming the skeletal assemblage of an unknown sample on the basis of its three main skeletal components. The diagram successfully characterises more than 85% of the New Zealand Cenozoic limestone samples and also appears to be applicable for the skeletal assemblage designation of many overseas examples of non-tropical carbonate deposits. Limitations relate mainly to locally common skeletal types (e.g. serpulids, brachiopods) that are presently not incorporated into the New Zealand-based scheme. The general ecological preferences of the main skeletal contributors in each of the seven skeletal assemblages form a basis for relating the assemblages to broad shelf habitats. Consequently, as well as the benefits of providing a more consistent skeletal assemblage terminology for comparative studies between different workers, the scheme can assist with the paleoenvironmental interpretation of non-tropical skeletal carbonate facies.  相似文献