Nutrients cause grassland biomass to outpace herbivory.

Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs ('consumer-controlled'). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food ('resource-controlled'). Using an experiment replicated in 58 grasslands spanning six continents, we show that nutrient addition and vertebrate herbivore exclusion each caused sustained increases in aboveground live biomass over a decade, but consumer control was weak. However, at sites with high vertebrate grazing intensity or domestic livestock, herbivores consumed the additional fertilization-induced biomass, supporting the consumer-controlled prediction. Herbivores most effectively reduced the additional live biomass at sites with low precipitation or high ambient soil nitrogen. Overall, these experimental results suggest that grassland biomass will outstrip wild herbivore control as human activities increase elemental nutrient supply, with widespread consequences for grazing and fire risk.

Construct validity of Wechsler factor scores.

The construct validity of the Verbal Comprehension. Perceptual Organization, and Freedom from Distractibility factor scores was examined in a sample of school-aged referred children. Examination of correlations between factor scores and neuropsychological and achievement tests generally supported the construct validity of the factors. The Verbal Comprehension factor was associated with verbal, quantitative, and concept-formation abilities. The Perceptual Organization factor was related to nonverbal concept formation, tactual performance, and visual attention. The Freedom from Distractibility factor demonstrated a complex pattern of correlations and appeared to reflect a range of abilities including quantitative, language, attentional, and concept formation.

Adaptations for independent infant care by mothers who are disabled.

The objective of this paper is to present information that will increase functional independence in the everyday tasks of infant care for mothers with a disability. It focuses on one mother and her special problems in caring for her first child. Physical and psychosocial adaptations are addressed encompassing the major functions of the mother with a disability in an effort to establish the individual's unique ability to function successfully as a parent. Physical adaptations to make child caring accessible in both the home environment and away from home are explored. This covers activities requiring reaching, lifting, carrying as well as changing and feeding. Psychosocial adaptations influencing the person with a disability as parent focus on attitudes, recongition of strengths and limitations, and the feeling of belongingness in society. It is hoped that this paper will provide greater insight about independent infant care by mothers who are disabled and also stimulate new ideas for occupational therapists.