Stress dependence of magnetization and magnetic properties of igneous rocks     

Maria Jeleńska 《Pure and Applied Geophysics》1975,113(1):635-649

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IGU Working Group on Geography on Transport     

Prof. Calogero Muscara  Prof. Dr. Günther Jacob  Prof. R. Caralp  Prof. Maria do Carmo Galvao  Prof. Shalom Reichman  Prof. Janes O. Wheeler 《GeoJournal》1981,5(6):589-593

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Oxidative stress in the mussel Mytella guyanensis from polluted mangroves on Santa Catarina Island,Brazil     

Torres MA  Testa CP  Gáspari C  Masutti MB  Panitz CM  Curi-Pedrosa R  de Almeida EA  Di Mascio P  Filho DW 《Marine pollution bulletin》2002,44(9):923-932

Digestive glands of the mangrove mussel Mytella guyanensis, collected at one non-polluted site (site 1) and two polluted sites (sites 2 and 3), were analysed for different antioxidant defenses, lipid peroxidation and DNA damage. Thiobarbituric acid-reactive substance (TBARS) and 8-oxo-7,8-dihydro-2'-deoxyguanosine levels were enhanced at the polluted sites. With the exception of superoxide dismutase, the activities of catalase and glutathione peroxidase were also higher at the polluted sites. Greater increases were observed in glutathione reductase, glutathione S-transferase and etoxyresorufine-O-deethylase activities at the polluted sites. Conversely, reduced glutathione content was higher at the control site. Trace metal contents in mussels collected at polluted sites were increased compared to the control site, and there were strong positive correlations between TBARS and Cu and Pb contents. M. guyanensis is routinely exposed to an oxidative stress condition at both polluted sites, and considering xenobiotic bioaccumulation in bivalve molluscs, the mangrove mussel represents an excellent bioindicator for environmental monitoring studies.  相似文献   

Determination of Gold in Ores by Isobutyl Methyl Ketone Extraction and Electrothermal Atomic Absorption Spectrometry: A Stability Study of the Metal in Organic Media     

Maria Inês C. Monteiro  Marcos Paulo A. Lavatori  Nilza Maria M. de  Oliveira 《Geostandards and Geoanalytical Research》2003,27(3):245-249

A method involving gold extraction into isobutyl methyl ketone (IBMK), after partial dissolution with aqua regia , with determination by electrothermal atomic absorption spectrometry is described. The pyrolysis and atomisation temperatures were optimized using a pyrolytic graphite forked platform. The stability study of gold in isobutyl methyl ketone extract indicated that closed polypropylene containers (3% absorbance measurement changes) were better than both open polypropylene and closed glass containers over periods of up to 22 hr. Satisfactory recoveries of 99 and 102% were obtained when Au, in the IBMK extracts from CH-3 and MA-2 reference materials, were determined after storage of the extracts in closed polypropylene containers for 22 hr, respectively.  相似文献   

Coals of the Brazil Formation (Pennsylvanian) in Indiana: observations of correlation inconsistencies and their implications     

Maria Mastalerz  Philip R. Ames  Penny L. Padgett   《International Journal of Coal Geology》2003,54(3-4):209

The coals of the upper part of the Mansfield, Brazil, and the lower part of the Staunton Formations (Atokan and Desmoinesian, Pennsylvanian) in Indiana (Illinois Basin) are characteristically thin and discontinuous. As a result, problems with correlation and identification of the seams have persisted for both researchers and industry. These discrepancies affect coal exploration, mine planning, and subsequently coal-fired utilities. This study presents exploration and operational examples demonstrating some of the correlation problems associated with the coals of the Brazil Formation, and the Upper Block and Lower Block, in particular, and the surrounding upper part of the Mansfield Formation and lower part of the Staunton Formations. Based on exploration boreholes, mine scale observations, and coal quality and petrographic data, this study suggests that (1) the coal mapped as the Upper Block Coal Member of Clay County may, in fact, be the same seam as the Lower Block Coal Member of Daviess County; and (2) the Lower Block coal of Clay County is not present south of the Switz City area of central Greene County, IN.  相似文献   

Seismic coupling and structure of the Hellenic subduction zone in the Ionian Islands region     

Mireille Laigle  Alfred Hirn  Maria Sachpazi  Christophe Clment 《Earth and Planetary Science Letters》2002,200(3-4):243-253

The western Hellenic arc has been commonly considered as a largely aseismic subduction zone, from the comparison of a small rate of shortening derived from the seismic moment release, with a large rate of convergence inferred from geology. Complete seismic coupling would instead be expected from models that consider a control by plate tectonic forces, because of the trenchward velocity of the Hellenic–Aegean upper plate now confirmed with GPS measurements. In the region of the Ionian Islands, a subduction interplate boundary has been recently imaged and its seismogenic downdip width suggested to be moderate, from reflection seismic profiling and local earthquake tomography. In the appropriate model for such an earthquake source region, which considers a single interplate fault and takes into account these features, the moderate seismic moment release is found consistent with complete seismic coupling of this subduction. The shallow downdip limit of the seismogenic zone can be interpreted as due to the interplate boundary being overlain there by the ductile deeper crust of the orogenically thickened Hellenides.  相似文献   

Assessment of exotic fish impacts on water quality and zooplankton in a degraded semi-arid floodplain wetland   总被引：1，自引：0，他引：1  

David G. Angeler  Miguel Álvarez-Cobelas  Salvador Sánchez-Carrillo  Maria A. Rodrigo 《Aquatic Sciences - Research Across Boundaries》2002,64(1):76-86

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Palaeomagnetic study of the El Quemado complex and Marifil formation, Patagonian Jurassic igneous province, Argentina   总被引：1，自引：0，他引：1  

Maria P. Iglesia Llanos  Roberto Lanza  Alberto C. Riccardi  Silvana Geuna  Marinella A. Laurenzi  Raffaella Ruffini † 《Geophysical Journal International》2003,154(3):599-617

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Early Records of Icebergs in the South Atlantic Ocean from Spanish Documentary Sources     

A. Maria del Rosario Prieto  B. Ricardo García-Herrera  Emiliano Hernández Martin 《Climatic change》2004,66(1-2):29-48

The use of documentary sources has proven useful to identify extremeclimatic events and their variability during the pre-instrumental period. Theaim of this paper is to describe iceberg sightings in the Western SouthAtlantic during the second half of the 18th century, as recorded from Spanishlogbooks. A total of five sightings have been found, two corresponding toisolated bergs and three to outbreaks. The relevance of these results istwofold: they are the first documented iceberg sightings to date and, aboveall, they correspond to very unusual episodes, characterized by a high numberof high-sized bergs and by the relatively low latitude of their location. Itis suggested that they could be associated to cold episodes in Antarctica.  相似文献   

Eustatic and climatic controls on the development of the Wahiba Sand Sea, Sultanate of Oman   总被引：3，自引：0，他引：3  

Dirk Radies  Frank Preusser  Albert Matter  Maria Mange† 《Sedimentology》2004,51(6):1359-1385

Aeolian sand sea accumulations can serve as valuable archives of climate change in continental environments. The Wahiba Sand Sea is situated at the northern margin of the area presently affected by Indian Summer Monsoon Circulation and it records environmental changes associated with this major climatic boundary over the last 160 000 years. The internal stratigraphy and evolution of the sand sea is investigated using a combination of outcrop, borehole, seismic and luminescence data. Proximity to the Indian Ocean means that the sand sea succession shows the influence of sea level changes on the sedimentary architecture and composition of the dune deposits. During the last two glacial periods, low global sea level was associated with a high input of bioclastic grains, reflecting the significance of subaerially exposed shelf areas as one of the main sources of aeolian sediment. The onset of aeolian sediment transport and deposition was related to the breakdown of stabilizing vegetation during arid periods that equate with sea level lowstands. The preservation of aeolian sediments by the formation of supersurfaces and associated palaeosoils took place during times of increased wetness and elevated groundwater tables. This interplay of constructive and destructive periods greatly influenced the sedimentary architecture. Oscillations of wet and dry periods between 160 000 and 130 000 years and 120 000–105 000 years ago are attributed to the evolution of a wet aeolian system. Younger periods of aeolian deposition around and after the last glacial maximum were characterized by dry aeolian conditions. No soil horizons developed during these times.  相似文献