Amorphous oxides of manganese as new sorbents of strontium ions

Samples with the best adsorption properties are selected as a result of investigations conducted on synthesis of manganese-dioxide-based materials and study of their physicochemical properties. Materials were selected on the basis of their low cost and the simplicity of their production technology. In the laboratory the synthesis and analyses of materials was carried out for selected samples. The sorption of a series of elements is studied for a more detailed investigation of materials obtained. The results obtained will promote the synthesis of materials with improved adsorption properties with the aim of their application for purification of water from strontium. It is shown that the most promising way for amendment of manganese oxide is modification of this material using acid-resistant oxides. These oxides are also less expensive than existing sorbents for strontium.     

Application of partial order to stream channel assessment at bridge infrastructure for mitigation management

Many environmental systems and infrastructure systems are monitored using a set of indicator values that assess several aspects of site condition. The values of different indicators often convey different comparative messages for the study sites. The comparability between sites is analyzed within the theory of partially-ordered sets and visualized with Hasse diagrams. This paper demonstrates that properties of partially-ordered sets and the conversion of indicator scores into a rank matrix provide a manager or decision-maker with valuable information that would be lost if the monitored indicator data were aggregated only into a single index. Stream stability assessment data from 49 bridge crossing sites in the United States are used to demonstrate these techniques in prioritization and identification of restoration and maintenance needs of stream channels at bridge crossings.     

Testing spatial cluster occurrence in maps equipped with environmentally defined structures

We propose a novel tool for testing hypotheses concerning the adequacy of environmentally defined factors for local clustering of diseases, through the comparative evaluation of the significance of the most likely clusters detected under maps whose neighborhood structures were modified according to those factors. A multi-objective genetic algorithm scan statistic is employed for finding spatial clusters in a map divided in a finite number of regions, whose adjacency is defined by a graph structure. This cluster finder maximizes two objectives, the spatial scan statistic and the regularity of cluster shape. Instead of specifying locations for the possible clusters a priori, as is currently done for cluster finders based on focused algorithms, we alter the usual adjacency induced by the common geographical boundary between regions. In our approach, the connectivity between regions is reinforced or weakened, according to certain environmental features of interest associated with the map. We build various plausible scenarios, each time modifying the adjacency structure on specific geographic areas in the map, and run the multi-objective genetic algorithm for selecting the best cluster solutions for each one of the selected scenarios. The statistical significances of the most likely clusters are estimated through Monte Carlo simulations. The clusters with the lowest estimated p-values, along with their corresponding maps of enhanced environmental features, are displayed for comparative analysis. Therefore the probability of cluster detection is increased or decreased, according to changes made in the adjacency graph structure, related to the selection of environmental features. The eventual identification of the specific environmental conditions which induce the most significant clusters enables the practitioner to accept or reject different hypotheses concerning the relevance of geographical factors. Numerical simulation studies and an application for malaria clusters in Brazil are presented.     

Effect of mercuric chloride on terrestrial slug Semperula maculata and histopathology of reproductive organs: a comprehensive study

Since the last few decades, terrestrial diversity is found to be under stress due to the contamination by various chemicals and gases of aquatic and agricultural media. The bioaccumulation of these compounds at certain concentrations in different tissues produces histopathological changes leading to behavioral changes in target animals. This study focused on terrestrial molluscan slug, Semperula maculata, against lethal concentrations of mercury chloride (HgCl₂). Bioaccumulation of Hg was highest in ovotestis, while lowest in the molluscan penis. Histopathological changes were observed in the cellular arrangement of reproductive organs. Alterations in the penis and the dart gland included dilated unicellular, multicellular glands, and muscular dystrophy, dilated peripheral glandular cells, respectively; dilation being maximal in the prostate gland. Ovotestis showed depleted number of gametocytes. Vacoulized pre-vitellogenic oocytes with early vitellogenic oocytes were noted under light microscopy. Mercury produced toxicity on secretory functions and lowered the rate of reproduction in animals. Evidence indicates that Hg produced gamete degeneration, impacted reproductive capacity and survival of this species in the ecosystem.     

Chitosan composites reinforced with nanostructured waste fly ash

Journal of Material Cycles and Waste Management - This paper outlines the preparation and characterization of chitosan (CS) composites reinforced with mechano-chemically activated fly ash (MCA-FA)....     

A performance indicator for ranked set sampling using ranking error probability matrix

Ranked set sampling (RSS) is a sampling procedure that has been shown to provide more efficient procedures than simple random sampling, in particular the Mann-Whitney-Wilcoxon (MWW) statistic and the empirical distribution function (EDF). We briefly review the work of Bohn (1992) and Stokes and Sager (1988) on the effect of imperfect ranking on the RSS-based MWW test and on the RSS-based EDF, respectively. We propose a model for a ranking error probability matrix which we hope will become a useful tool for evaluating RSS-based statistical procedures