Imprints of Dark Energy on Cosmic Structure Formation I) Realistic Quintessence Models and the Non-Linear Matter Power Spectrum

Dark energy as a quintessence component causes a typical modification of the background cosmic expansion, which in addition to its clustering properties, can leave a potentially distinctive signature on large scale structures. Many previous studies have investigated this topic, particularly in relation to the non-linear regime of structure formation. However, no careful pre-selection of viable quintessence models with high precision cosmological data was performed. Here we show that this has led to a misinterpretation (and underestimation) of the imprint of quintessence on the distribution of large scale structures. To this purpose we perform a likelihood analysis of the combined Supernova Ia UNION dataset and WMAP5-years data to identify realistic quintessence models. Differences from the vanilla LambdaCDM are especially manifest in the predicted amplitude and shape of the linear matter power spectrum, though these remain within the uncertainties of the SDSS data. We use these models as benchmark for studying the clustering properties of dark matter halos by performing a series of high resolution N-body simulations. We find that realistic quintessence models allow for relevant differences of the dark matter distribution with the respect to the LambdaCDM scenario well into the non-linear regime, with deviations up to 40% in the non-linear power spectrum. Such differences are shown to depend on the nature of DE, as well as the scale and epoch considered. At small scales (k~1-5 h Mpc^{-1}, depending on the redshift) the structure formation process is about 20% more efficient than in LambdaCDM. We show that these imprints are a specific record of the cosmic structure formation history in DE cosmologies and therefore cannot be accounted in standard fitting functions of the non-linear matter power spectrum.Comment: 24 pages, 11 figures. Higher resolution paper available at http://cp3.phys.ucl.ac.be/upload/papers/astro-ph-0903.5490.ps (ps) and http://cp3.phys.ucl.ac.be/upload/papers/astro-ph-0903.5490.pdf (pdf). v2: New discussion on the non-linear power spectrum at small scales. v3: same as v2 with corrected references. Matches version to appear in MNRA

Análisis de la flota dedicada a la pesca de corvina rubia y distribución de tallas del desembarque. Período 1992-1995

En el presente trabajo se describe la estructura y eficiencia de la flota dedicada a la pesca de corvina. Los resultado muestran que existen dos estratos delimitados por buques de 17.25 metros eslor y 345 HP de potencia y que los más eficientes son los de menores dimensiones. Durante el período 1992-1995 se analizó el muestreo de desembarque y se determinó una disminución de la longitud media de corvina y una mayor presencia de individuos juveniles en las capturas. Esta situación coincidió con un incremento tanto de volúmenes desembarcados como del esfuerzo de pesca. Respecto de años anteriores, en dicho período se produjo, además un aumento de las exportaciones de corvina y una mayor actividad de la flota en la zona denominada "El Salado" (35º 57' - 36º 57' S).Fil: Carozza, Claudia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Perrota, Ricardo G.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Cotrina, Carmen P.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Bremec, Claudia Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; ArgentinaFil: Aubone, Aníbal. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentin