8 research outputs found
Oasis en el océano: los frentes costeros del Mar Argentino
En el Atlántico argentino es posible reconocer zonas dinde distintas aguas con caracterÃstica propias se encuentran. Ello ocasiona que aguas ricas en nutrientes sean movidas hacia la superficie, dando base a una alta producción biológica. Se describen la generación de frentes de mareas, se caracterizan por ejemplo, los frentes marinos, el frente del talud continental, el de la penÃnsula de Valdés (prov. Chubut, Argentina), y el frente estuarial del RÃo de la Plata. Este trabajo de divulgación cientÃfica analiza la importancia ecológica de los frentes y además las posibilidades que brindan nuevas tecnologÃas satelitales que contribuirán a mejorar la comprensión del funcionamiento de los sistemas
El estuario del Plata: donde el rÃo se encuentra con el mar
The Rio de la Plata estuary is one of the largest estuarine environments of South America. It is characterized by a two-layer vertical salinity distribution and the existence of water masses convergence zones (fronts). Oceanographic scenario greatly influence the biology of the planktonic organisms that live in the water column, the benthic organisms that inhabit the soft sediment bottoms of the estuary, and the fishes, which show a differential degree of penetration into the diluted water of the estuary. Short and frequent events of strong weastward winds ('sudestada') alter completely the oceanographic conditions greatly influencing the especies ecology. Biological production of the estuary is high, and most of their organisms have a marine heritage
Proton strangeness form factors in (4,1) clustering configurations
We reexamine a recent result within a nonrelativistic constituent quark model
(NRCQM) which maintains that the uuds\bar s component in the proton has its
uuds subsystem in P state, with its \bar s in S state (configuration I). When
the result are corrected, contrary to the previous result, we find that all the
empirical signs of the form factors data can be described by the lowest-lying
uuds\bar s configuration with \bar s in P state that has its uuds subsystem in
state (configuration II). Further, it is also found that the removal of the
center-of-mass (CM) motion of the clusters will enhance the contributions of
the transition current considerably. We also show that a reasonable description
of the existing form factors data can be obtained with a very small probability
P_{s\bar s}=0.025% for the uuds\bar s component. We further see that the
agreement of our prediction with the data for G_A^s at low-q^2 region can be
markedly improved by a small admixture of configuration I. It is also found
that by not removing CM motion, P_{s\bar s} would be overestimated by about a
factor of four in the case when transition dominates over direct currents.
Then, we also study the consequence of a recent estimate reached from analyzing
the existing data on quark distributions that P_{s\bar s} lies between 2.4-2.9%
which would lead to a large size for the five-quark (5q) system, as well as a
small bump in both G^s_E+\eta G^s_M and G^s_E in the region of q^2 =< 0.1
GeV^2.Comment: Prepared for The Fifth Asia-Pacific Conference on Few-Body Problems
in Physics 2011 in Seoul, South Korea, 22-26 August 201