Disc galaxies can be substantially modified by close encounters and mergers, since their discs are very responsive components. Close interactions can be held responsible for the formation of bridges and tails, as well as for the formation of some bars, asymmetries and grand design spirals. Bound clumps can form in the tails, due to self-gravity, and could evolve to dwarf galaxies. Off-centering...

Glaucoma is a chronic eye disease that leads to vision loss. Since it cannot be cured, detecting the disease in time is important. The tests which are done to detect Glaucoma using intraocular pressure (IOP) are not sensitive enough for population based glaucoma screening. The assessment of Optic nerve head damage in retinal fundus images is both more promising and superior. In this paper the o...

A contraction Tdefined on a complex Hilbert space is called Acompact if there exists a nonzero function/analytic in the open unit disc and continuous on the closed disc such that f( T) is a compact operator. In this paper, the factorization of / is used to obtain a structure theorem which describes the spectrum of T. Introduction. A bounded linear operator T on a complex Banach space X is calle...

even though intervertebral disc degeneration can be found in the natural course of alkaptonuria, detection of the disease by black disc color change in a patient without any other presentation of alkaptonuria is an exceptionally rare condition. we have reported a very rare case of alkaptonuria presented with low back pain and steppage gait in a 51-year-old male with a complaint of chronic low-b...

The formation of a protolunar disc by a giant impact with the early Earth is discussed, focusing on two classes of impacts: (i) canonical impacts, in which a Mars-sized impactor produces a planet-disc system whose angular momentum is comparable to that in the current Earth and Moon, and (ii) high-angular-momentum impacts, which produce a system whose angular momentum is approximately a factor o...

We prove a global Birkhoff decomposition for almost split real forms of loop groups, when an underlying finite dimensional Lie group is compact. Among applications, this shows that the dressing action by the whole subgroup of loops which extend holomorphically to the exterior disc on the U -hierarchy of the ZS-AKNS systems, on curved flats and on various other integrable systems, is global for ...

Abstract: In this paper, a comparison between h ig h e r order schemes has been performed in terms of numerical accuracy. Four finite difference schemes, the e xp lic it fourth-order compact Pade scheme, the implicit fourth-order Pade scheme, flowfield dependent variation (FDV) meth o d a n d h igh order compact flowfie ld dependent variation (HOC-FDV) scheme are tes ted. The FDV scheme is used...

The discovery is reported of emission features in the X-ray spectrum of GROJ1655-40 obtained using RossiXTE on 1997, Feb 26. The features have been fitted firstly by two Gaussian lines, which in four spectra have average energies of 5.85± 0.08 keV and 7.32± 0.13 keV, strongly suggestive that these are the red and blue shifted wings of an iron disc line from material with velocity ∼0.33 c. The b...

We consider hard-disc mixtures with disc sizes within ratio 2?1, that is, the small exactly fits in hole between four large discs. For each prescribed stoichiometry of and discs, densest packings are rigorously determined via a computer-assisted proof. The density is maximal for 1:1 stoichiometry: discs then form square grid interstitial site which nests. When there an excess made single phase ...

We report on V and R high speed photometry of the dwarf nova EX Dra in quiescence and in outburst. The analysis of the outburst lightcurves indicates that the outbursts do not start in the outer disc regions. The disc expands during the rise to maximum and shrinks during decline and along the following quiescent period. The decrease in brightness at the later stages of the outburst is due to th...