Density linear perturbations in Einstein-Cartan two fluid cosmolo-gies where the outer model is an isotropic Friedmann solution with closed model while the inner model is a flat anisotropic Einstein-Cartan (EC) cosmology with shear are computed by taking into consideration superhorizon situations.This situation is in agreement with the present isotropy of the Cosmic Background Radiation where t...

We study a sample of 43 early-type galaxies, selected from the Sloan Digital Sky Survey (SDSS) because they appeared to have velocity dispersions of σ ≥350 kms. Highresolution photometry in the SDSS i passband using the High-Resolution Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope shows that just less than half of the sample is made up of superpositions of two o...

This article reviews the prevailing paradigm for how galaxies and larger structures formed in the universe: gravitational instability. Basic observational facts are summarized to motivate the standard cosmological framework underlying most detailed investigations of structure formation. The observed universe approaches spatial uniformity on scales larger than about 1026 cm. On these scales grav...

We study the general structure of models for structure formation, with applications to the reverse engineering of the model from observations. Through a careful accounting of the degrees of freedom in covariant gravitational instability theory, we show that the evolution of structure is completely speci ed by the stress history of the dark sector. The study of smooth, entropic, sonic, scalar an...

Recently evidence has accumulated that there are various interactions between the different levels of the central reticular core of the brain stem. (DELL, BONVALLET and HUGELIN 1961 ; MORUZZI 1964). The present study was initiated to know how the mesencephalic reticular formation (MRF) acts to regulate activity of the pontine reticular formation (PRF). This MRF-originated, descending effect con...