OBJECTIVE To determine the prevalence of extended spectrum b-lactamase at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia and to compare the ability of the disc diffusion, double disc potentiation methods and the extended-spectrum b-lactamase E test to detect exended-spectrum b-lactamase among enterobacteriaceae. METHODS This study was undertaken during the time period period...

there are many different ways to subdivide the spectrum of a bounded linear operator; some of them aremotivated by applications to physics (in particular, quantum mechanics). in this study, the relationship betweenthe subdivisions of spectrum which are not required to be disjoint and goldberg's classification are given.moreover, these subdivisions for some summability methods are studied.

Let K be a Banach space, B a unital C∗-algebra, and π : B → L(K) an injective, unital homomorphism. Suppose that there exists a function γ : K×K → R+ such that, for all k, k1, k2 ∈ K, and all b ∈ B, (a) γ(k, k) = ‖k‖2, (b) γ(k1, k2) ≤ ‖k1‖ ‖k2‖, (c) γ(πbk1, k2) = γ(k1, πb∗k2). Then for all b ∈ B, the spectrum of b in B equals the spectrum of πb as a bounded linear operator on K. If γ satisfies ...

For A ? L(X), B L(Y) and C L(Y,X) we denote by MC the operator matrix defined on X Y = (A 0 B). In this paper, prove that ?qF(A) ?qF(B) [ C?L(Y,X) ?qF(MC) ?p(B) ?p(A?), where ?qF(.) (resp. ?p(.)) denotes quasi-Fredholm spectrum point spectrum). Furthermore, consider some sufficient conditions for to be have ?qF(MC).