Showing papers by "Cochrane Collaboration published in 1992"

Getting to grips with Archie Cochrane's agenda.

Abstract: Future drought is projected to occur under warmer temperature conditions as climate change progresses, referred to here as global-change-type drought, yet quantitative assessments of the triggers and potential extent of drought-induced vegetation die-off remain pivotal uncertainties in assessing climate-change impacts. Of particular concern is regional-scale mortality of overstory trees, which rapidly alters ecosystem type, associated ecosystem properties, and land surface conditions for decades. Here, we quantify regional-scale vegetation die-off across southwestern North American woodlands in 2002-2003 in response to drought and associated bark beetle infestations. At an intensively studied site within the region, we quantified that after 15 months of depleted soil water content, >90% of the dominant, overstory tree species (Pinus edulis, a pinon) died. The die-off was reflected in changes in a remotely sensed index of vegetation greenness (Normalized Difference Vegetation Index), not only at the intensively studied site but also across the region, extending over 12,000 km2 or more; aerial and field surveys confirmed the general extent of the die-off. Notably, the recent drought was warmer than the previous subcontinental drought of the 1950s. The limited, available observations suggest that die-off from the recent drought was more extensive than that from the previous drought, extending into wetter sites within the tree species9 distribution. Our results quantify a trigger leading to rapid, drought-induced die-off of overstory woody plants at subcontinental scale and highlight the potential for such die-off to be more severe and extensive for future global-change-type drought under warmer conditions.

Classrooms for Emotionally and Behaviorally Disturbed Students: Facing the Challenge:

Abstract: There is an increasing consensus among interested groups that the Education for the Handicapped Act has delivered less than was expected for the 374,000 children identified by the schools as having emotional and behavioral disorders (Forness, 1989; Knitzer, 1982). Drawing on a recently completed national study of public education for children la beled emotionally and behaviorally disturbed (EBD) by the schools, At the School House Door: An Examination of Programs and Policies for Children with Behavioral and Emotional Problems (Knitzer, Steinberg, & Fleisch, 1990), this article focuses on daily classroom life of these children and aims to do three things: It describes some of these authors' most prob lematic findings related to curriculum, behavior management, and mental health services; it highlights alternatives to the prevailing current practices that were identified; and it examines the implications of both the problems and the possibilities for practitioners, researchers, and teacher trainers.