A preliminary look at source-receptor relationships in the Texas-Mexico border area.

Several factors have recently caused visibility impairment at Big Bend National Park, TX, to be of interest. Analyses of historical data collected there have shown that visibility is poorer and fine particle concentrations are higher at Big Bend than at other monitored Class I areas in the western United States. In addition, air masses frequently arrive there after crossing Mexico, where emissions are not well known. During September and October 1996, a field study was undertaken to begin examining the aerosol, visibility, and meteorology on both sides of the border. Results indicate that, during the study, the largest fractions of fine mass and light extinction at Big Bend were due to sulfates and the trace elements most closely associated with sulfate particles were Na and Se. Based on back trajectory modeling and the spatial, temporal, and inter-species relationships in the fine particle concentrations measured during the study, sulfates arrived at the park from both Mexico and the United States. Se was higher in Texas than in Northern Mexico, while V, Pb, Zn, Ni, and Mn were on average much higher in Mexico.

A quality assurance process in health sciences libraries.

A goal of libraries is to assure the improvement of library services. Many organizations have attempted to use standards as a method to assure quality services, but often standards have failed through a lack of individual commitment to those standards and to the methodology used in establishing the standards. Many segments of the health care field have adopted the concept of quality assurance and are applying it to the service and care they provide. This process has the potential to raise or assure quality of service in health sciences libraries. The process involves: selecting a subject for review; developing measurable criteria; ratifying the criteria; evaluating existing services using the criteria; identifying problems; analyzing problems; developing solutions; implementing solutions; and reevaluating services. Two pilot quality assurance studies conducted in the Midwest Health Science Library Network during 1978 are described. Plans are under way to use this process on a regional basis.