Coping with an intra-institutional relocation: behavioral change as a function of residents' personal resources

A model of person-environment interaction was used to help explain the impact of an intra-institutional relocation on the behavior of residents who varied in mobility and mental status. Environmental measures indicated that the new building provided more prosthetic features, fewer orientational aids, a more complex floorplan, and increased distance between the social areas and the nurses' stations. Behavioral observations of a sample of 17 residents showed varying adaptations to these environmental changes. Wheelchair-mobile residents benefited from the improved accessibility, whereas immobile residents experienced reduced stimulation and further restriction of their spatial range. High mental status residents were drawn out of their bedrooms into social spaces. while low mental status residents spent less time in social areas and more in the halls near the nurses' stations, where they could maintain contact with the staff. Information such as this on the differential impact of a new building can contribute to the design process and to program modification aimed at optimizing resident functioning.     

Identification of nonionic detergents by GC/CI-MS: I. A complementary method or an attractive alternative to GC/EI-MS and other methods?

Tertiary octylphenol and lauryl alcohol ethoxylates (with one to six oxyethylene groups) have been detected in the effluent from the primary clarifiers of wastewater treatment plant, using their chemical ionization (CI) mass spectra. The GC/CI-MS appears to be a very suitable method for the selective identification of these compounds.     

Persistence of rock-derived nutrients in the wet tropical forests of La Selva, Costa Rica

We used strontium isotopes and analysis of foliar and soil nutrients to test whether erosion can rejuvenate the supply of rock-derived nutrients in the lowland tropical rain forest of La Selva, Costa Rica. We expected that these nutrients would be depleted from soils on stable surfaces, a result of over one million years of weathering in situ. In fact, trees and palms in all landscape positions derive a relatively high percentage (> or =40%) of their strontium from bedrock, rather than atmospheric, sources. The fraction that is rock-derived increases on slopes, but with no detectable effect on plant macronutrient concentrations. These results differ from those in a similar ecosystem on Kauai, Hawaii, where plants on uneroded surfaces derive almost all of their foliar Sr from atmospheric, rather than bedrock, sources. The results from La Selva challenge the assumption that tropical Oxisols in general have low nutrient inputs from bedrock, and support the hypothesis that erosion can increase the supply of these nutrients in lower landscape positions.     

A trait-based test for habitat filtering: convex hull volume

Community assembly theory suggests that two processes affect the distribution of trait values within communities: competition and habitat filtering. Within a local community, competition leads to ecological differentiation of coexisting species, while habitat filtering reduces the spread of trait values, reflecting shared ecological tolerances. Many statistical tests for the effects of competition exist in the literature, but measures of habitat filtering are less well-developed. Here, we present convex hull volume, a construct from computational geometry, which provides an n-dimensional measure of the volume of trait space occupied by species in a community. Combined with ecological null models, this measure offers a useful test for habitat filtering. We use convex hull volume and a null model to analyze California woody-plant trait and community data. Our results show that observed plant communities occupy less trait space than expected from random assembly, a result consistent with habitat filtering.