949 resultados para Seneca, Lucius Annaeus, approximately 4 B.C.-65 A.D.
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To investigate the seasonal and interannual variations in biological productivity in the South China Sea (SCS), a Pacific basin-wide physical - biogeochemical model has been developed and used to estimate the biological productivity and export flux in the SCS. The Pacific circulation model, based on the Regional Ocean Model Systems (ROMS), is forced with daily air-sea fluxes derived from the NCEP (National Centers for Environmental Prediction) reanalysis between 1990 and 2004. The biogeochemical processes are simulated with a carbon, Si(OH)(4), and nitrogen ecosystem (CoSiNE) model consisting of silicate, nitrate, ammonium, two phytoplankton groups (small phytoplankton and large phytoplankton), two zooplankton grazers (small micrograzers and large mesozooplankton), and two detritus pools. The ROMS-CoSiNE model favourably reproduces many of the observed features, such as ChI a, nutrients, and primary production (PP) in the SCS. The modelled depth-integrated PP over the euphotic zone (0-125 m) varies seasonally, with the highest value of 386 mg C m (-2) d (-1) during winter and the lowest value of 156 mg C m (-2) d (-1) during early summer. The annual mean value is 196 mg C m (-2) d (-1). The model-integrated annual mean new production (uptake of nitrate), in carbon units, is 64.4 mg C m (-2) d (-1) which yields an f-ratio of 0.33 for the entire SCS. The modelled export ratio (e-ratio: the ratio of export to PP) is 0.24 for the basin-wide SCS. The year-to-year variation of biological productivity in the SCS is weaker than the seasonal variation. The large phytoplankton group tends to dominate over the smaller phytoplankton group, and likely plays an important role in determining the interannual variability of primary and new production.
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Documento de catorce fotografías, trece a color y una en blanco y negro, de diferentes grados de resolución y dimensiones diversas.
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17 fotografías, dieciséis en tono de grises.
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19 fotografías dieciséis a color.
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15 fotografías a color.
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10 fotografías, nueve a color.
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54 fotografías a color (algunos archivos presentan bajo pixelaje).
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35 fotografías a color.
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7 fotografías a color.
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18 fotografías a color.
C 174 INST-D 2013. 355 Réplicas talladas en piedra de esculturas precolombinas (San Agustín - Huila)
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5 fotografías a color.
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57 fotografías, cicuenta y cuatro a color.
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18 fotografías a color.
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24 fotografías a color.
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10 fotografías a color.