Observations of a flat density profile in the cores of dark-matter-dominated halos on the two extremes of mass for virialized objects in the universe, dwarf galaxies and galaxy clusters, present a serious challenge to the current standard theory of structure formation involving Cold Dark Matter (CDM). By contrast, N-body simulations of halo formation in the latter indicate density profiles whic...

the morphology of retinal photoreceptor layer was studied in continuous light-exposed and dark-adapteddomestic male cats (felis catus). the eyes of 12 healthy adult cats (4 in continuous light-exposed group, 4 in continuous dark-adapted group, and 4 in control group) were routinely fixed and studied by electron microscope. results showed that the general structure of photoreceptor layer in this...

We study weak gravitational lensing of galaxy clusters in terms of the MOND (modified Newtonian dynamics) theory. We calculate shears and convergences of background galaxies for three clusters (A1689, CL 0024+1654, and CL 1358+6245) and the mean profile of 42 SDSS (Sloan Digital Sky Survey) clusters and compare them with observational data. The mass profile is modeled as a sum of X-ray gas, gal...

Several lines of evidence suggest that the galaxy cluster Cl0024+17, an apparently relaxed system, is actually a collision of two clusters, the interaction occurring along our line of sight. Recent lensing observations suggest the presence of a ring-like dark matter structure, which has been interpreted as the result of such a collision. In this paper we present N -body simulations of cluster c...

objectives : optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients’ costs and radiation dose. this study sought to evaluate the effects of different viewing conditions on radiographic interpretation. materials and methods: this diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 hol...

to breaking dormancy as well as the effect of light, temperature, salinity and drought stress on germination of cutleaf mignonette seeds, experiments were conducted at the research laboratory of birjand faculty of agriculture in 2009. immersion in sulfuric acid (96%) for 30 seconds under continuous dark regime resulted in the highest germinability (73%) and the lowest germination (8%). was obse...

We construct a high resolution mass map of the z = 0.39 cluster 0024+1654, based on parametric inversion of the associated gravitational lens. The lens creates eight well-resolved sub-images of a background galaxy, seen in deep imaging with the Hubble Space Telescope. Excluding mass concentrations centered on visible galaxies, more than 98% of the remaining mass is represented by a smooth conce...

We present a comprehensive mass reconstruction of the rich galaxy cluster Cl 0024+17 at z ≃ 0.4 from ACS data, unifying both strongand weak-lensing constraints. The weak-lensing signal from a dense distribution of background galaxies (∼ 120 arcmin) across the cluster enables the derivation of a high-resolution parameter-free mass map. The strongly-lensed objects tightly constrain the mass struc...