Inhibitory factors affecting the process of enhanced biological phosphorus removal (EBPR) – A mini-review

Enhanced biological phosphorus removal (EBPR) technology has been widely considered as a key strategy in preventing eutrophication and recognized as the advancing front of research in wastewater treatment. The key to keep its high efficiency in biological phosphorus removal is to optimize the operation and management of the system. Previous research in this field has undoubtedly improved understanding of the factors hindered overall efficiency of EBPR. However, it is obvious that much remains to be learnt. This paper attempts to review the fundamental understanding in factors inhibiting the stability and reliability of the EBPR systems in the state-of-the-art research. In view of modeling the EBPR systems, an appropriate extension of the current mechanistic models with these inhibitory factors is recommended in order to better simulate and predict the behavior of full-scale and lab-scale EBPR plants. From the perspectives of the further mechanistic and multi-factors study, the direction of denitrifying dephosphatation and granules/biofilms are also discussed. This comprehensive overview will not only help us to understand the overall mechanism of the EBPR process, but also benefit the researchers and engineers to consider all the possible factors affecting the process in the urban sewage treatment plants.     

Molecular Simulation of Solution Conformations of the Amyloid β-Peptide Aβ(1–42) by a Backpropagation Neural Network Model

Abstract

The predictive power of solution-dependent conformational states of the Aβ(1–42) peptide of Alzheimer's disease by an optimized backpropagation neural network was tested. It was found that the neural network simulates well the solution-dependent conformations. The model was also examined by using geometry-optimized conformations (hybrid approach of Gasteiger charges plus MM+ molecular-mechanics) where the initial coordinates were obtained by NMR solution spectroscopy.     

Recent activities of the Microbiology in Schools Advisory Committee

Ecology and evolution

Agricultural education

Evolution and education

Education division elections

ISII in Europe

Tree project

Science teaching scholarship

Biology of terrestrial arthropods

A microscopied museum     

Mesocyclops longisetus effects on survivorship of Aedes aegypti immature stages in car tyres

Abstract .The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus , and the survival data were compared using log–linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test . Survivorship curves were constructed for each treatment.
In the absence of M. longisetus , the survivorship of Ae. aegypti immature stages averaged 9%. The highest mortality rate was observed during the fourth larval instar (54%) and the resulting survival pattern corresponded to a type II survivorship curve. The mortality rate of Ae. aegypti first-instar larvae (fifty per tyre) increased more than 200-fold in the presence of M. longisetus (twenty per tyre) and the highest mortality was during the first two larval instars, where it reached 98.9%, with a resulting survivorship of 0.2%. Overall mortality was sixfold greater in the presence of the copepod than in its absence. The survival pattern of immature stages of Ae. aegypti in the presence of the copepod corresponded to a type III survivorship curve. As M. longisetus was so effective against Ae. aegypti immature stages in tyres under semi-natural conditions, its long-term effectiveness should be evaluated under socially and ecologically realistic field conditions in Mexico.     

The recolonization of the Krakatau islands by termites (Isoptera), and their biogeographical origins

The termite assemblages of the Krakatau islands and five sites in Sumatra and Java were investigated, using a standardized transect sampling method. Five species were found on the Krakatau islands that have not been collected there before. The total number of termites recorded on the islands since the 1883 volcanic eruption is now twelve species, all of which are wood feeders. No termites nesting in or feeding on the soil were found on the Krakataus, suggesting that rafting in wood is the primary method by which the termites recolonized the islands.     

Environment versus dispersal in the assembly of western Amazonian palm communities

Aim It is a central issue in ecology and biogeography to understand what governs community assembly and the maintenance of biodiversity in tropical rain forest ecosystems. A key question is the relative importance of environmental species sorting (niche assembly) and dispersal limitation (dispersal assembly), which we investigate using a large dataset from diverse palm communities. Location Lowland rain forest, western Amazon River Basin, Peru. Methods We inventoried palm communities, registering all palm individuals and recording environmental conditions in 149 transects of 5 m × 500 m. We used ordination, Mantel tests and indicator species analysis (ISA) to assess compositional patterns, species responses to geographical location and environmental factors. Mantel tests were used to assess the relative importance of geographical distance (as a proxy for dispersal limitation) and environmental differences as possible drivers of dissimilarity in palm species composition. We repeated the Mantel tests for subsets of species that differ in traits of likely importance for habitat specialization and dispersal (height and range size). Results We found a strong relationship between compositional dissimilarity and environmental distance and a weaker but also significant relationship between compositional dissimilarity and geographical distance. Consistent with expectations, relationships with environmental and geographical distance were stronger for understorey species than for canopy species. Geographical distance had a higher correlation with compositional dissimilarity for small‐ranged species compared with large‐ranged species, whereas the opposite was true for environmental distance. The main environmental correlates were inundation and soil nutrient levels. Main conclusions The assembly of palm communities in the western Amazon appears to be driven primarily by species sorting according to hydrology and soil, but with dispersal limitation also playing an important role. The importance of environmental characteristics and geographical distance varies depending on plant height and geographical range size in agreement with functional predictions, increasing our confidence in the inferred assembly mechanisms.