Tracer-derived estimates of hydraulic resistance and transient hydraulic
storage were related to measures of pool volume and channel morphometric
variability in small streams of the Oregon coast, U.S.A. Fourteen
100 m study reaches in 3 streams were selected to compare channel
and hydraulic characteristics in streams representing a time series...
Current bioassessment efforts are focused on small wadeable streams, at least partly because assessing ecological conditions in non-wadeable large rivers poses many additional challenges. In this study, we sampled 20 sites in each of seven large rivers in the Pacific Northwest, USA, to characterize variation of benthic diatom assemblages among...
An understanding of the interactions among local environmental factors (e.g., physical habitat and water quality) and aquatic assemblages is essential to conserve biodiversity in tropical and subtropical headwater streams. We evaluated the relative importance of multiple physical and chemical habitat variables that influence the richness of Ephemeroptera, Plecoptera, and Trichoptera...
Macroinvertebrates are important for processing leaf detritus in temperate streams, but studies about their role in tropical streams often present conflicting results. Via digestive tract analyses, we assessed the diets of Phylloicus sp. larvae (Trichoptera: Calamoceratidae), collected from streams of two southeastern Brazil river basins (Araguari, Sao Francisco). We classified...
Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely...
Full Text:
. Ferreiraa, Kele R. Firmianoa,
eborah R.O. Silvaa, Raphael Ligeiroc, PhilipR. Kaufmannd, Marcos
Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely...
Full Text:
biological metric (r >
090)
Selected to
final analisys
Diference between least-
and most-disturbed
Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely...
Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely...
Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely...
Most studies dealing with the use of ecological indicators and other applied ecological research rely on some definition or concept of what constitutes least-, intermediate- and most-disturbed condition. Currently, most rigorous methodologies designed to define those conditions are suited to large spatial extents (nations, ecoregions) and many sites (hundreds to...
Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine...
A model to simulate the dry-process pressing of wood
composites is presented. The model uses as its starting
point a pre-existing mass and heat transfer model.
A number of furnish material properties, including
fluid permeability, thermal conductivity, hygroscopicity and
rheological parameters, are reviewed and modified for use in
the pressing...
The objective of this study was to measure the consequences of alternative
forest management intensification programs. These consequences
include future harvest levels, silvicultural labor and capital
requirements, and the income and employment generated directly and indirectly.
The system utilizes the Timber Resource Economic Estimation
System (TREES) model, a harvest scheduling...
Pacific madrone, tanoak, and California black oak are the most economically promising native California hardwoods. Volume and value data indicate upward trends in growing stock levels and prices received for their products. These trends are likely to continue. They suggest research is particularly needed for: (1) seed fall and
regeneration,...
Rat selenoprotein W (SeW) promoter activity was investigated using different concentrations of cadmium, copper, and zinc. Two fragments (404bp and 1265bp) of the SeW promoter, containing a single metal response element (MRE), were ligated into the multiple cloning site of a pGL3-Basic reporter plasmid. The constructs were transfected into cultured...
Selenium deficiency in rats results in increased carbon metabolism,
approaching twice the rate of selenium supplemented animals
(normal). This is also reflected in a 50 percent increase in lysosomal
enzyme activity in tissues of selenium deficient animals.
Isolation of rat liver lysosomes shows a 17 percent increase in
membrane thickness...