Marine science in the western Indian Ocean responds to population pressures and climate change     

Jos Paula  Michael H. Schleyer 《Estuarine, Coastal and Shelf Science》2009,84(3)

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Geochemical mobility of arsenic in the surficial waters from Argentina     

Alicia Daniela Robles  Paula Polizzi  María Belén Romero  Leila Natalia Chiodi Boudet  Sandra Medici  Agustín Costas  Marcela Gerpe 《Environmental Earth Sciences》2016,75(23):1479

The presence of arsenic (As) in surface water constitutes an important environmental risk, where mobility and adsorption processes are responsible for its behavior in the sediment–water interface. Therefore, the assessment of adsorption, mobility and water availability of arsenic in freshwater sediments, with agricultural, livestock and urban soil uses was performed. Arsenic concentrations in sediments ranged from 5.4 to 15.9 mg kg^?1 (total) and 2.8 to 6.5 mg kg^?1 (labile), and those of iron and manganese were 11,563–23,500 and 140.6–662.1 mg kg^?1, respectively. The As levels in water were significantly lower than those of sediments. Results would suggest that As co-precipitation and adsorption on Fe oxides are probably the major route of immobilization, determining its low lability. Manganese did not present an outstanding contribution to the retention, and cation-exchange capacity, pH and organic matter of sediments did not show an influence on the mobility of As.  相似文献   

Über das Vorkommen des Aluminiums in einer ooidische Eisenerze enthaltenden marinen Schichtfolge     

Paula Schneiderhöhn 《Contributions to Mineralogy and Petrology》1964,10(2):141-151

Ohne Zusammenfassung Herrn Prof. Dr.Carl W. Correns zum 70. Geburtstag gewidmet.  相似文献   

Population structure of Merluccius merluccius along the Iberian Peninsula coast     

Castillo  Ana G.F.; Alvarez  Paula; Garcia-Vazquez  Eva 《ICES Journal of Marine Science》2005,62(8):1699-1704

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Testing the accuracy of synthetic stellar libraries     

Lucimara P. Martins  Paula Coelho 《Monthly notices of the Royal Astronomical Society》2007,381(4):1329-1346

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Cave bear occupation in Schwabenreith Cave,Austria, during the early last glacial: constraints from 230Th/U‐dated speleothems     

Christoph Sptl  Denis Scholz  Gernot Rabeder  Paula J. Reimer 《第四纪科学杂志》2019,34(6):424-432

The cave bear was a prominent member of the Upper Pleistocene fauna in Eurasia. While breakthroughs were recently achieved with respect to its phylogeny using ancient DNA techniques, it is still challenging to date cave bear fossils beyond the radiocarbon age range. Without an accurate and precise chronological framework, however, key questions regarding the palaeoecology cannot be addressed, such as the extent to which large climate swings during the last glacial affected the habitat and possibly even conditioned the final extinction of this mammal. Key to constraining the age of cave bear fossils older than the lower limit of radiocarbon dating is to date interlayered speleothems using ²³⁰Th/U. Here we report new results from one such site in the Eastern European Alps (Schwabenreith Cave), which yielded the highest density of bones of cave bear (Ursus spelaeus eremus). Although dating of the flowstones overlying this fossiliferous succession was partly compromised by diagenetic alteration, the ²³⁰Th/U dates indicate that the bear hibernated in this cave after about 113 ka and before about 109 ka. This time interval coincides with the equivalent of Greenland Stadial 25, suggesting possible climate control on the cave bear's habitat and behaviour. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd  相似文献   

Collisional evolution of Trans-Neptunian populations: Effects of fragmentation physics and estimates of the abundances of gravitational aggregates     

Paula G. Benavidez 《Planetary and Space Science》2009,57(2):201-215

The Trans-Neptunian region is yet another example of a collisional system of small bodies in the Solar System. In the last decade the number of TNOs with reliable orbital elements is steadily increasing and even if it is still premature to compare models with observations, we can start to have some idea of the orbital structure and magnitude distribution, so that some loose constraints may be set on the critical parameters that affect collisional evolution. With this aim we have developed a model for the collisional evolution of the Trans-Neptunian region by dividing it into three main different populations, corresponding to the dynamical classification proposed by Gladman et al. [2001.The structure of the Kuiper Belt: size distribution and radial extent. Astrophys. J. 122, 1051] (Resonant region, Classical Belt and Scattered Disk). A multi-zone collisional model is developed, in which each zone can collisionally interact with each other. The model takes into account the known physics of the fragmentation of icy/rocky bodies at the typical relative velocities of TNOs, according to velocity distributions corresponding to each evolving zone. The dependence of the evolution of the considered populations on physically critical collisional parameters is investigated and the corresponding results are presented, including estimates of the abundance of gravitational aggregates in the studied populations.  相似文献   

Magnetotelluric measurements at Eusebio,an equatorial station     

N.B. Trivedi  Elesbão G. de Souza  Eurico R. de Paula  J.M. da Costa  Hugo Fournier 《Physics of the Earth and Planetary Interiors》1981,25(3):241-244

Magnetotelluric measurements in the period range 100–86400 s were conducted at a coastal station under the equatorial electrojet (Eusebio, 3.87°S, 321.58°E). The magnetotelluric data were hand-scaled and analysed to obtain a scalar apparent resistivity profile at Eusebio. The depth of the intermediate conducting layer was found to be in the range 45–75 km and the final conducting layer seems to begin at a depth of about 350 km. Possible effects of the source field equatorial electrojet are discussed and our results are compared with those of an African station under the equatorial electrojet.  相似文献   

Chemical composition and stable carbon isotopic ratios of crude oils from Southern Germany     

Paula Hahn-Weinheimer  Alfred Hirner 《Organic Geochemistry》1980,2(1):45-53

Thirty crude oils were sampled in the South German Molasse Basin. The crude oils were chemically separated into five component groups and their stable carbon isotopic ratios were determined by mass spectrometry. A distinct differentiation of four regionally connected groups can be inferred from the results of the δ¹³C values and chemical analyses. This grouping is in accordance with the present geologic information on the origin of crude oils in the Molasse Basin.The chemistry of crude oils seems to have been influenced by secondary processes in the eastern part of the Molasse Basin.  相似文献   

Eine vergleichende Studie über Methoden zur quantitativen Bestimmung von Abrundung und Form an Sandkörnern (Im Hinblick auf die Verwendbarkeit an Dünnschliffen.)     

Paula Schneiderhöhn 《Contributions to Mineralogy and Petrology》1954,4(1-2):172-191

Zusammenfassung Kurze Darlegung der zur Verwendung an Sandkornern geeigneten Methoden zur Ermittlung von Abrundung und Form. Vergleichende Betrachtung der an 25 Kernprojektionen mit den verschiedenen Methoden erzielten Untersuchungsergebnisse. Anwendung der gemachten Erfahrungen auf den Dünnschliff unter Erörterung der hierbei auftretendon besonderen Fragen und Schwierigkeiten.Herrn Professor Dr.Carl W. Correns zum 60. Geburtstag gewidmet.  相似文献