Spatialized ecosystem indicators in the southern Benguela   总被引：1，自引：2，他引：1  

Freon  Pierre; Drapeau  Laurent; David  Jeremy H.M.; Fernandez Moreno  Almudena; Leslie  Rob W.; Oosthuizen  W. Herman; Shannon  Lynne J.; van der Lingen  Carl D. 《ICES Journal of Marine Science》2005,62(3):459-468

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Response of hematological and biochemical parameters to heavy metal exposure: Implications in environmental monitoring     

William H. Benson  Carl F. Watson  Kevin N. Baer  R.Allan Stackhouse 《Marine environmental research》1988,24(1-4)

The use of selected hematological and biochemical parameters as indicators of metal exposure in aquatic organisms was evaluated. The hematological and biochemical parameters examined include glucose, hematocrit and aminotransferase levels in golden shiners exposed to cadmium. Cadmium exposure produced significant alterations in the levels of glucose, aspartate aminotransferase and alanine aminotransferase; however, hematocrit was not altered by exposure to cadmium. In addition, the comparative activity of Na/K adenosine triphosphatase (ATPase) was evaluated in the fathead minnow, golden shiner and bluegill sunfish. Basal Na/K ATPase activity was lowest in golden shiner (1·01 μmol Pi/mg protein/h) and highest in bluegill sunfish (1·45 μmol Pi/mg protein/h). While a stimulation of Na/K ATPase activity was observed at an exposure concentration of 1 μg Cd/liter in the fathead minnow and bluegill sunfish, inhibition of enzymatic activity was observed at higher exposure concentrations (10 and 100 μg Cd/liter). Gill Na/K ATPase activity in golden shiner was not significantly influenced by cadmium exposure. The observed insensitivity of ATPase in shiner may, in part, be related to higher background and accumulated concentrations of cadmium in gill tissue.  相似文献   

The filtering effect of orbit correction on geopotential errors     

Jaroslav Klokočník  Carl A. Wagner  J. Kostelecky  M. Jandová 《Journal of Geodesy》1995,70(3):146-157

Summary The geophysical interpretation of satellite tracking residuals generally ignores the filtering effect of initial orbit correction on the true errors of the model. While the filtered information is usually regarded as lost, knowing the spectral characteristics of the filter is a great aid in the detailed interpretation of residuals, especially of global data sets. In this regard, we derive the filter characteristics (admittances) of orbit correction in the presence of geopotential-caused trajectory errors. We then apply the filter to determine the likely power of the lost radial information in crossover differences of sea heights determined from satellite altimetry or in the latitude lumped coefficients derived from them. For example, we find that resonant geopotential information with periods longer than the corrected orbit's arc length is largely lost in residual crossover data. Results are given for GEOSAT, ERS-1 and TOPEX/Poseidon in their Exact Repeat Missions, using calibrated variancecovariance matrices of the harmonic geopotential coefficients of several recent Earth gravity models. To prove that filtering is important, we first employed a simple cut of all perturbing terms with periods longer than the general tracking period (4 days for GEOSAT and ERS-1, and 10 days for TOPEX). But the cut is too crude a method from a theoretical viewpoint, and thus, we developed two new filters. A comparison of their admittances explains the differences (and sometimes anomalous behaviour) between them and the cut. Many numerical examples (single-satellite crossover errors and latitude lumped coefficient errors, as projected from the variance-covariance matrices) are presented.This paper has been presented during the Panel on Satellite Dynamics, at COSPAR 1994, in Hamburg, Germany.  相似文献   

A quantum-mechanical study of the relative stability under pressure of MgSiO3-ilmenite,MgSiO3-perovskite,and MgO-periclase+SiO2-stishovite assemblage     

Ph. D'Arco  G. Sandrone  R. Dovesi  E. Aprà  V. R. Saunders 《Physics and Chemistry of Minerals》1994,21(5):285-293

The relative stability of MgSiO₃-ilmenite, MgSiO₃-perovskite and (periclase+stishovite) assemblage phases as a function of the pressure is investigated with the periodic quantum mechanical ab initio HartreeFock program CRYSTAL. For the first time, the structure of MgSiO₃-ilmenite is fully optimized. Basis set effects are explored. It turns out that relatively small basis sets reproduce correctly experimental geometries. However, larger basis sets (triple zeta quality, plus polarization d functions) are needed to yield significant thermochemical results. All contributions to the 0 K enthalpy are discussed. On the basis of the present highest level calculations, it appears that in the explored range of pressure (0P< 60=" gpa)=" the=" mineralogical=" assemblage=" periclase+stishovite=" has=" higher=" enthalpy=" than=">₃-ilmenite or perovskite, and that ilmenite transforms to orthorhombic perovskite around to 29.4 GPa in good agreement with experimental data extrapolated down to 0 K.  相似文献   

Background,conceptual structure and organizational-administrative establishing of a “sustainable development strategy” for Coral Islands     

Christoph Preu  Carl Engelbrecht 《GeoJournal》1994,33(4):433-442

Minitope coral islands represent one third of the islands located in the tropical Indo-Pacific. Subsistence farming and extensive agriculture dominate the traditional structure of income. As the lack of natural resources, infrastructure and capital restrict the developmental changes, the islands' natural environment has been utilized as economic potential. Planning and realization of land use systems introduced have, however, often been based on an insufficient data basis and have often inadequately considered the consequences of human impacts on the natural environment and its controlling factors. The result was environmental degradation and ecological destruction, affecting also the population's socioeconomic situation and in some cases rendering alternative land use impossible. Therefore, the long-term utilization of coral islands and, hence, the economic development of those countries require a specific development strategy. Based on the environmental and socioeconomic consequences of touristic utilization of coral islands in the Maldivian Archipelago, the model for a sustainable development strategy and its aims are derived, and the objectives, the conceptual structure, and the way of establishing them organizationally and administratively are presented.  相似文献   

Book reviews     

Yu. N. Korenkov  Carl W. Cable  Vernon F. Cormier  Vassily Levin  Jacek A. Majorowicz  Yehuda Bock  Waclaw M. Zuberek  Teng-fong Wong  William L. Power  Gary A. Robbins  Piotr Raczka  Krzysztof E. Haman  Katarzyna Chałasinska-Macukow  Ryszard Balcer  Henryk Piwkowski 《Pure and Applied Geophysics》1991,137(3):309-336

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The last lavas erupted during the main phase of the Siberian flood volcanic province: results from experimental petrology     

Linda T. Elkins-Tanton  David S. Draper  Carl B. Agee  Jessica Jewell  Andrew Thorpe  P. C. Hess 《Contributions to Mineralogy and Petrology》2007,153(2):191-209

The final lavas of the Siberian flood basalts are a ∼1,000 m thick section of meimechites, high-alkali, high-titanium, hydrous lavas that contrast sharply with the tholeiites that precede them. This paper presents a phase equilibrium study indicating that a candidate primary meimechite magma with 1 wt% water originated at ∼5.5 GPa and 1,700°C, both hotter and shallower than other estimates for melting beneath continental lithosphere. The experiments also suggest that a higher volatile content was involved in meimechite source genesis. Both the absence of orthopyroxene in any experiment and the close field association with carbonatites suggest that the meimechite source region may have been metasomatized with a CO₂-rich fluid. A small additional quantity of CO₂ and water would move magma origination to ∼1,550–1,600°C.  相似文献   

Finite-frequency tomography using adjoint methods—Methodology and examples using membrane surface waves     

Carl Tape  Qinya Liu  Jeroen Tromp 《Geophysical Journal International》2007,168(3):1105-1129

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Radiation stress due to ocean waves and the resulting currents and set-up/set-down     

Carl Newell  Thomas Mullarkey  Mark Clyne 《Ocean Dynamics》2006,56(3-4):376-376

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Road Traffic and Avalanches – Methods for Risk Evaluation and Risk Management     

Krister Kristensen  Carl Bonnevie Kristensen  Alf Harbitz 《Surveys in Geophysics》2003,24(5-6):603-616

This paper considers the methods for risk analysis and management in connection with avalanches and road traffic. Examples with calculations of encounter probability and quantification of uncertainty are given, along with suggestions for risk management in Norway.  相似文献