Transit agencies in the USA must provide service under increasing operating constraints. Using data from 1989-1993, technical efficiency among these firms is estimated and characteristics indicative of differential efficiency in transit agencies are identified. This paper verifies the robustness of the second step regression results to the choice of efficiency measure by comparing results of the two step regressions using a pair of non-parametric efficiency estimators. It is discovered that the structure of government subsidy to this industry negatively affects not just cost efficiency, but technical efficiency as well. Furthermore, maintenance appears to be an important component of operational efficiency in this industry.

Early-thymectomized (Tx) Xenopus frogs, which are permanently deficient in T cells, are used as a model sytem for the characterization of novel monoclonal antibodies (mAb) which identify candidate NK cells at the amphibian level of evolution. Hybridomas, generated from mice immunized with splenocytes from Tx Xenopus following B cell and thrombocyte depletion , were screened by flow cytometry. Three mAb (1F8, 4D4 and 1G5) were identified that stained increased proportions of splenocytes from Tx compared with control frogs. These mAb identified lymphoid populations from Xenopus spleen, liver and gut which, after 48 h culture in growth factor-rich medium, exhibited spontanous killing of MHC-deficient allotu-mor targets. mAb-defined splenocytes also rapidly induced apoptosis of such tumor targets. Dual color analysis confirmed that NK cells are neither T nor B cells. Cytospins of spleno-cytes isolated with anti-NK mAb revealed large lymphoid cells with distinct pseudopodia. Immunohistology indicated each anti-NK mAb routinely labeled cells within the gut epithe-lium but NK cells were difficult to visualize in spleen sections. Western blotting of spleen, liver and intestinal lysates subjected to sodium dodecyl sulfate polyacrylamide gel electro-phoresis showed that 1G5 reacted strongly with protein bands of˚70of˚of˚70-85 kDa, whereas mAb 1F8 and 4D4 stained less intensely, but identified similar protein bands.

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This article describes the experiences of a Canadian multidisciplinary critical care team striving to reduce the incidence of ventilator-associated pneumonia (VAP). Several interventions, including a VAP bundle, were used and applied across a health region. Our regional VAP rate has seen a steady decline over the past 12 months and has been largely under our goal of 9.8 cases per 1,000 ventilator-days. The team's success in lowering VAP has provided the momentum for sustained improvement, which has spread to other areas.