  In order to test the expansion of the universe and its geometry, we carry out
an Alcock & Paczynski cosmological test, that is, an evaluation of the ratio of
observed angular size to radial/redshift size. The main advantage of this test
is that it does not depend on the evolution of the galaxies, but only on the
geometry of the universe. However, the redshift distortions produced by the
peculiar velocities of the gravitational infall do also have an influence,
which should be separated from the cosmological effect. We derive the
anisotropic correlation function of sources in three surveys within the Sloan
Digital Sky Survey (SDSS): galaxies from SDSS-III/Baryon Oscillation
Spectroscopy Survey-Data Release 10 (BOSS-DR10), and QSOs from SDSS-II and
SDSS-III/BOSS-DR10. From these, we are able to disentangle the dynamic and
geometric distortions and thus derive the ratio of observed angular size to
radial/redshift size at different redshifts. We also add some other values
available in the literature. Then, we use the data to evaluate which
cosmological model fits them. We used six different models: concordance
Lambda-CDM, Einstein-de Sitter, open-Friedman Cosmology without dark energy,
flat quasi-steady state cosmology, a static universe with a linear Hubble law,
and a static universe with tired-light redshift. Only two of the six models
above fit the data of the Alcock & Paczynski test: concordance Lambda-CDM and
static universe with tired-light redshift; whereas the rest of them are
excluded at a >95% confidence level. If we assume that Lambda-CDM is the
correct one, the best fit with a free Omega_m is produced for
Omega_m=0.24^{+0.10}_{-0.07}.
