Homogeneous Cotton solitons

Left-invariant Cotton solitons on homogeneous manifolds are determined. Moreover, algebraic Cotton solitons are studied providing examples of non-invariant Cotton solitons, both in the Riemannian and Lorentzian homogeneous settings

Deterministic and probabilistic models for the estimation of nitrate loads in a rural basin

En este trabajo se desarrolló un modelo probabilístico que utiliza la teoría de la función de densidad de probabilidades derivada para estimar la carga media anual de nitratos transportada por el escurrimiento superficial, utilizando una relación funcional entre el escurrimiento y la carga de nitratos. El modelo determinístico hidrológico y de calidad de agua denominado Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) fue utilizado para estimar la carga de nitratos en el escurrimiento superficial. Este modelo emplea como variable de entrada la precipitación diaria observada en la Estación del Aeropuerto de Olavarría durante el período 1988 a 2002. Para la calibración del modelo se aplicó una nueva metodología que estima la incertidumbre en los valores observados. Ambos modelos probabilístico y determinístico se aplican en una subcuenca rural del arroyo Tapalqué (provincia de Buenos Aires, Argentina) y finalmente se comparan los valores de la carga de nitratos estimados con los dos modelos con las observaciones realizadas en la sección del arroyo motivo de este estudio. Los resultados muestran que la carga media de nitratos obtenida con el modelo probabilístico es del mismo orden de magnitud que los valores medios observados y estimados con el modelo hidrológico y de calidad de agua SWRRB-WQ.In this work a new probabilistic model was developed. The new model applies the derived density function theory to estimate nitrate mean annual load transported by surface runoff. A functional relationship between runoff and nitrate load was used. The deterministic hydrologic and water quality model Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) was used to estimate nitrate load in surface runoff. This model uses, as input variable, daily precipitation observed at Olavarría Airport Meteorological Station, for the 1988-2002 period. For model calibration a new method that estimates uncertainty in observed values is applied. Both probabilistic and deterministic hydrologic models are applied in a rural subbasin of Tapalqué River (province of Buenos Aires, Argentina). Finally, estimated and observed nitrate loads are compared at the outlet section of the subbasin under study. The results of applying the selected probabilistic model show that the mean nitrate loads obtained, are of the same order of magnitude that the mean nitrate loads observed and estimated with the SWRRB-WQ hydrologic and water quality model.Fil: Gelmi, Mónica E.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería.Fil: Seoane, Rafael. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto Nacional del Agua

O papel das populações tradicionais na conservação da biodiversidade.

bitstream/CNPF-2009-09/42622/1/Doc153.pdf1 CD-ROM

Estudos fitossociológicos em agroflorestas e regeneração natural na floresta atlântica densa.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Recuperação de áreas degradadas como instrumento para a conservação das florestas nativas.

Palestra

The distribution of old stars around the Milky Way's central black hole I: Star counts

(abridged) In this paper we revisit the problem of inferring the innermost structure of the Milky Way's nuclear star cluster via star counts, to clarify whether it displays a core or a cusp around the central black hole. Through image stacking and improved PSF fitting we push the completeness limit about one magnitude deeper than in previous, comparable work. Contrary to previous work, we analyse the stellar density in well-defined magnitude ranges in order to be able to constrain stellar masses and ages. The RC and brighter giant stars display a core-like surface density profile within a projected radius R<0.3 pc of the central black hole, in agreement with previous studies, but show a cusp-like surface density distribution at larger R. The surface density of the fainter stars can be described well by a single power-law at R<2 pc. The cusp-like profile of the faint stars persists even if we take into account the possible contamination of stars in this brightness range by young pre-main sequence stars. The data are inconsistent with a core-profile for the faint stars.Finally, we show that a 3D Nuker law provides a very good description of the cluster structure. We conclude that the observed stellar density at the Galactic Centre, as it can be inferred with current instruments, is consistent with the existence of a stellar cusp around the Milky Way's central black hole, Sgr A*. This cusp is well developed inside the influence radius of about 3 pc of Sgr A* and can be described by a single three-dimensional power-law with an exponent gamma=1.23+-0.05. The apparent lack of RC stars and brighter giants at projected distances of R < 0.3 pc (R<8") of the massive black hole may indicate that some mechanism has altered their distribution or intrinsic luminosity.Comment: Accepted for publication A&

Sistematização de técnicas de plantio e manejo de agroflorestas.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos