This paper identifies two notions of substitutes for auction and equilibrium analysis. Weak substitutes, which is the usual price-theory notion, guarantees monotonicity of tâtonnement processes and convergence of clock auctions to a pseudoequilibrium, but only strong substitutes, which treats each unit traded as a distinct good with its own price, guarantees that every pseudo-equilibrium is a W...

The article discusses the possibility of using glycerol as an additive to engine fuel in order reduce tendency combustion knock, and thus increase octane number a given fuel. Experimental tests were carried out on UIT-85 research with variable compression ratio from eight eleven test intensity knock. completely renewable fuel—the blend butanol 25 75%, respectively—was tested. A comparative anal...

BACKGROUND The presence of keratinized tissue around dental implants is more than desirable either from a functional and aesthetic point of view, making soft tissue grafting a common practice in implant rehabilitation. Autogenous soft tissue grafting procedures are usually associated with high morbidity. Aim of this study was to assess the efficacy of a xenogeneic collagen matrix as a substitut...

AIM OF THE WORK This prospective study was carried out at the National Cancer Institute, Cairo University. The aim of this study is to evaluate the use of the ileocecal segment as a vaginal substitute in young female patients undergoing vaginal resection for malignant pelvic tumors. PATIENTS AND METHODS The study included eleven patients with different pelvic malignancies undergoing vaginal r...