Species composition, density, and temporal dynamics of zooplankton were studied in six reservoirs in a semi-arid region in tropical northeastern Brazil (Rio Grande do Norte state). All the reservoirs are highly eutrophic, with high contents of total nitrogen (minimum of 1200 µg.L(-1)) and total phosphorus (minimum of 10 µg.L(-1)), and extremely high algal biomass was registered (surpassing 20 µ...

PURPOSE To evaluate adolescents' perception of the causes of obesity, with emphasis on differences according to nutritional status and socioeconomic position. METHODS We conducted qualitative research including 80 adolescents belonging to the 1993 Pelotas (Brazil) Birth Cohort Study, and their mothers. We classified adolescent boys and girls into four groups (girls-obese, girls-eutrophic, boy...

OBJECTIVE Determine associations between the quality of life of mothers and the nutritional status of children. METHODS case-control study involving 152 mothers of children aged zero to five years, living in the coverage area of a basic health unit in the city of Porto Alegre. The calculation of sample size was estimated as 152 mothers - 76 mothers with children at nutritional risk/malnutriti...

The aand l-glucosidase activity in natural samples can be readily measured during short incubation times (20 min) by using the artificial substrates 4-methylumbelliferyl-a-D-glucoside and 4-methylumbelliferyli--Dglucoside. The apparent Km of both aand ,I-glucosidase for these respective substrates is 0.01 ,uM. The homologous disaccharides maltose and cellobiose competitively inhibit aand I-gluc...

We studied nutrient uptake in relation to water chemistry, stream hydrodynamics, and ecosystem metabolism in two eutrophic lowland streams located near Berlin, Germany. Ambient nutrient uptake rates ranged from 0.180 to 12.880 g NO3-N m22 d21, from 0.035 to 0.517 g NH4-N m22 d21, and from 0.017 to 0.750 g PO4-P m22 d21. Temporal and spatial variability in nutrient uptake rates within single str...

Abstract Eutrophication is a process characterized by the enrichment of given aquatic environment with nutrients, triggering serious and growing ecological problem in continental ecosystems, including effects on biodiversity ecosystem functioning. For this, we predicted that eutrophication decreases zooplankton functional richness, evenness, divergence dispersion, changes composition zooplankto...

The task of providing leading indicators of catastrophic regime shifts in ecosystems is fundamental in order to design management protocols for those systems. Here we address the problem of lake eutrophication (that is, nutrient enrichment leading to algal blooms) using a simple spatial lake model. We discuss and compare different spatial and temporal early warning signals announcing the catast...

OBJECTIVE To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents. MATERIALS AND METHODS This prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescent...

Lake Võrtsjärv (270 km2, mean depth 2.8 m, Estonia) is an eutrophic and turbid lake (Secchi depth 0.5-1 m) with a high nutrient load (total nitrogen 1-2 mg N l(-1), total phosphorus approximately 50 microg P l(-1)) leading to a highly productive phytoplankton population (average chlorophyll a concentration 24 microg l(-1)). Seasonal dynamics of the main members of pelagic microbial loop - phyto...

Using data from 1387 lakes collected over three decades, we found a wide range in the concentrations of total phosphorus (TP), total nitrogen (TN) and chlorophyll in Florida lakes, and that edaphic factors as outlined by the USEPA’s Florida Lake Regions were the dominant factor in determining the concentrations of plant nutrients in the state’s lakes. The hypothesis that all eutrophic lakes in ...