832 resultados para Rodas de conversa


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Recent benthic foraminifera (> 125 µm) were investigated from multicorer samples on a latitudinal transect of 20 stations between 1°N and 32°S along the upper slope off West Africa. Samples were selected from a narrow water depth interval, between 1200 and 1500 m, so that changes in water masses are minimized, but changes in surface productivity are important and the only significant environmental variable. Live (Rose Bengal stained) benthic foraminifera were counted from the surface sediment down to a maximum of 12 cm. Dead foraminifera were investigated in the top 5 cm of the sediment only. Five live and five dead benthic foraminiferal assemblages were identified using Q-mode principal component analysis, matching distinct primary productivity provinces, characterized by different systems of seasonal and permanent upwelling. Differences in seasonality, quantity, and quality of food supply are the main controlling parameters on species composition and distribution of the benthic foraminiferal faunas. To test the sensitivity of foraminiferal studies based on the uppermost centimeter of sediment only, a comparative Q-mode principal component analysis was conducted on live and dead foraminiferal data from the top 1 cm of sediment. It has been demonstrated that, on the upper slope off West Africa, most of the environmental signals as recorded by species composition and distribution of the 'total' live and dead assemblages, i.e., including live and dead foraminifera from the surface sediment down to 12 cm and 5 cm, respectively, can be extracted from the assemblages in the top centimeter of sediment only. On the contrary, subsurface abundance maxima of live foraminifera and dissolution of empty tests strongly bias quantitative approaches based on the calculation of standing stocks and foraminiferal numbers in the topmost centimeter.

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Living (Rose Bengal stained) benthic foraminifera were collected with a multicorer from six stations between 2°N and 12°S off West Africa. The foraminiferal communities in the investigated area reflect the direct influence of different productivity regimes, and are characterized by spatially and seasonally varying upwelling activity. At five stations, foraminiferal abundance coincides well with the gradient of surface productivity. However, at one station off the Congo River, the influence of strong fresh water discharge is documented. Although this station lies directly in the center of an upwelling area, foraminiferal standing stocks are surprisingly low. It is suggested that the Congo discharge may induce a fractionation of the organic matter into small and light particles of low nutritional content, by contrast to the relatively fast-sinking aggregates found in the centers of high productivity areas. Quality and quantity of the organic matter seem to influence the distribution of microhabitats as well. The flux of organic carbon to the sea-floor controls the sequence of degradation of organic matter in sediment and the position of different redox fronts. The vertical foraminiferal stratification within sediment closely parallels the distribution of oxygen and nitrate in porewater, and reflects different nutritive strategies and adaptation to different types of organic matter. The epifauna and shallow infauna colonize oxygenated sediments where labile organic matter is available. The intermediate infauna (M. barleeanum) is linked to the zone of nitrate reduction in sediments where epifaunal and shallow infaunal species are not competitive anymore, and must feed on bacterial biomass or on metabolizable nutritious particles produced by bacterial degradation of more refractory organic matter. The deep infauna shows its maximum distribution in anoxic sediments, where no easily metabolizable organic matter is available.

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Author's pseud., Apaikán, at head of title.

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Contiene: Primera Parte. Corona poetico-musical que una gran parte de literatos y algunos profesores de música españoles del siglo XIX, consagran a la buena memoria del célebre diplomatico y distinguido escritor español el Excmo. Sr. D. José Nicolas de Azara y Perera -- Segunda parte. Notas á la Corona poetica : traducciones a algumas de las poesias insertas en dialectos provinciales, aclaraciones y cartas que las esplican. Discurso historico-arqueológico sobre la musica en general, y en particular la española, escrito en honor á la buena memoria del siglo XVIII, el Excmo. Sr. D. Jose Nicolas de Azara y Perera ... / por su historiador Basilio Sebastian Castellanos de Losada. Discurso historico-arqueologico sobre el baile en general, y en particular del español, escrito en honor á la buena memoria del célebre diplomático y literato el Excmo. Sr. D. José Nicolas de Azara y Perera ... / por su historiador Basilio Sebastian Castellanos de Losada.

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Primera serie. Ligeia. -- Eleonora. -- Berenice. -- Morella. -- La caiguda de la casa Usher. -- El retrat oval. -- William Wilson. -- La mascara de la mort roja. -- El rei pesta. -- El pou 1 el Pèndol. -- Segona serie. El gat negre. -- El cor delator. -- El barril d'amontillado. -- Hop. -- Frog. -- Metzengerstein en el cas de M. Valdemar. -- L'illa de la fada. -- El poder de les paraules. -- Conversa d'Eiros i Charmion. -- Col·Lo-qui de monos i una. -- Uns quants mots amb una monia.

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Available on demand as hard copy or computer file from Cornell University Library.

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Paraphrase erroneously attributed to Andronicus Rhodius, or to Andronicus Callistus, and by Constantinus Palaeokappa falsely to an unknown Heliodorus of Prusa

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Mode of access: Internet.

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Mode of access: Internet.

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Printer's imprint (p. 388): Claude Simon.