Invertebrates from the Low Head Member (Polonez Cove Formation, Oligocene) at Vaureal Peak, King George Island, West Antarctica

Eight taxa of marine invertebrates, including two new bivalve species, are described from the Low Head Member of the Polonez Cove Formation (latest early Oligocene) cropping out in the Vaureal Peak area, King George Island, West Antarctica. The fossil assemblage includes representatives of Brachiopoda (genera Neothyris sp. and Liothyrella sp.), Bivalvia (Adamussium auristriatum sp. nov., ?Adamussium cf. A. alanbeui Jonkers, and Limatula (Antarctolima) ferraziana sp. nov.), Bryozoa, Polychaeta (serpulid tubes) and Echinodermata. Specimens occur in debris flows deposits of the Low Head Member, as part of a fan delta setting in a high energy, shallow marine environment. Liothyrella sp., Adamussium auristriatum sp. nov. and Limatula ferraziana sp. nov. are among the oldest records for these genera in King George Island. In spite of their restrict number and diversification, bivalves and brachiopods from this study display an overall dispersal pattern that roughly fits in the clockwise circulation of marine currents around Antarctica accomplished in two steps. The first followed the opening of the Tasmanian Gateway at the Eocene/Oligocene boundary, along the eastern margin of Antarctica, and the second took place in post-Palaeogene time, following the Drake Passage opening between Antarctic Peninsula and South America, along the western margin of Antarctica.

Estudio económico de América Latina 1959: versión preliminar = Economic survey of Latin America 1959: preliminary version

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Spatial and temporal variability in soil CO2-C emissions and relation to soil temperature at King George Island, maritime Antarctica

Few studies have examined the effects of temperature on spatial and temporal trends in soil CO2-C emissions in Antarctica. In this work, we present in situ measurements of CO2-C emissions and assess their relation with soil temperature, using dynamic chambers. We found an exponential relation between CO2 emissions and soil temperature, with the value of Q10 being close to 2.1. Mean emission rates were as low as 0.026 and 0.072 g of CO2-C m-2 h-1 for bare soil and soil covered with moss, respectively, and as high as 0.162 g of CO2-C m-2 h-1 for soil covered with grass, Deschampsia antarctica Desv. (Poaceae). A spatial variability analysis conducted using a 60-point grid, for an area with mosses (Sannionia uncianata) and D. antarctica, yielded a spherical semivariogram model for CO2-C emissions with a range of 1 m. The results suggest that soil temperature is a controlling factor on temporal variations in soil CO2-C emissions, although spatial variations appear to be more strongly related to the distribution of vegetation types. © 2010 Elsevier B.V. and NIPR.

Tasas de inmigración femenina por grupos de edad para la ciudad de Santiago, 1910-1959

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La mortalidad en la República Argentina según tablas de vida de 1914, 1946-48 y 1959-61

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República Argentina: algunos efectos sociales y económicos derivados de la baja mortalidad entre 1900 y 1960

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America Latina: algunas consideraciones demograficas del proceso de metropolizacion, 1900-1960

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La mortalidad de la República Argentina según tablas de vida de 1914, 1946-48 y 1959-61

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Guatemala: las diferencias socioeconómicas de la fecundidad, 1959-1980

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Republica Argentina: evaluacion y ajuste del censo de poblacion de 1960 por sexo y edad y tabla abreviada de mortalidad, 1959-1961

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Tabla abreviada de mortalidad, Republica de Mexico 1959-1961

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Republica Argentina: evaluacion y ajuste del censo de poblacion de 1960 por sexo y edad y tabla abreviada de mortalidad, 1959-1961

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Tablas completas de mortalidad para la República Argentina, 1959-1961

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Evaluación y ajuste del censo de población de 1960 por sexo y edad y tabla abreviada de mortalidad 1959-1961

Versión completa publicada por el Centro Latinoamericano de Demografía: E/CN.CELADE/C.32, Santiago, Chile 1964

Tendencias económicas de América Latina en 1959 = Economic trends in Latin America in 1959

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