in this paper some upper and lower bounds for the greatest eigenvalues of the pi and vertex pimatrices of a graph g are obtained. those graphs for which these bounds are best possible arecharacterized.

background: fractures of distal radius are one of the most common fractures seen by physicians and account for 20% of all fractures seen in the emergency room. various factors contribute in secondary displacement of fracture fragments after anatomic or near anatomic close reduction and cast immobilization in distal radius fractures. this study was designed to examine the correlation between rad...

the degree set of a graph is the set of its degrees. kapoor et al. [degree sets for graphs, fund. math. 95 (1977) 189-194] proved that for every set of positive integers, there exists a graph of diameter at most two and radius one with that degree set. furthermore, the minimum order of such a graph is determined. a graph is 2-self- centered if its radius and diameter are two. in this paper for ...

A solution is presented to a doubly mixed boundary value problem of the torsion of an elastic layer, partially resting on a rigid circular base by a circular rigid punch attached to its surface. This problem is reduced to a system of dual integral equations using the Boussinesq stress functions and the Hankel integral transforms. With the help of the Gegenbauer expansion formula of the Bessel f...

We investigate the uplink of a power-controlled multi-user distributed antenna system (DAS) with antennas deployed on a circle. Applying results from random matrix theory, we prove that for such a DAS, the per-user sum rate and the total transmit power both converge as user number and antenna number go to infinity with a constant ratio. The relationship between the asymptotic per-user sum rate ...

We describe a 59-year-old man who had nonunion of a right distal radius fracture after volar locking plate fixation. He underwent open reduction and internal fixation with a volar locking plate system for a dorsally displaced, unstable distal radius fracture at a previous hospital 5 months ago. Radiographs of the injured wrist showed nonunion of the distal radius with 1.5-mm ulnar minus varianc...

PURPOSE To describe the effect of the corneal asphericity and toricity on the map patterns and best fit sphere (BFS) characteristics in elevation topography. METHODS The corneal surface was modeled as a biconic surface of principal radii and asphericity values of r1 and r2 and Q1 and Q2, respectively. The apex of the biconic surface corresponded to the origin of a polar coordinates system. Mi...