Model-based approach to the detection and classification of mines in sidescan sonar

This paper presents a model-based approach to mine detection and classification by use of sidescan sonar. Advances in autonomous underwater vehicle technology have increased the interest in automatic target recognition systems in an effort to automate a process that is currently carried out by a human operator. Current automated systems generally require training and thus produce poor results when the test data set is different from the training set. This has led to research into unsupervised systems, which are able to cope with the large variability in conditions and terrains seen in sidescan imagery. The system presented in this paper first detects possible minelike objects using a Markov random field model, which operates well on noisy images, such as sidescan, and allows a priori information to be included through the use of priors. The highlight and shadow regions of the object are then extracted with a cooperating statistical snake, which assumes these regions are statistically separate from the background. Finally, a classification decision is made using Dempster-Shafer theory, where the extracted features are compared with synthetic realizations generated with a sidescan sonar simulator model. Results for the entire process are shown on real sidescan sonar data. Similarities between the sidescan sonar and synthetic aperture radar (SAR) imaging processes ensure that the approach outlined here could be made applied to SAR image analysis.     

Purification and physicochemical characterization of ovine beta-lactoglobulin and alpha-lactalbumin

Ovine whey proteins were fractionated and studied by using different analytical techniques. Anion-exchange chromatography and reversed-phase high-performance liquid chromatography (HPLC) showed the presence of two fractions of beta-lactoglobulin but only one of alpha-lactalbumin. Gel permeation and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis allowed the calculation of the apparent molecular mass of each component, while HPLC coupled to electrospray ionisation-mass spectrometry (ESI-MS) technique, giving the exact molecular masses, demonstrated the presence of two variants A and B of ovine beta-lactoglobulin. Amino acid compositions of the two variants of beta-lactoglobulin differed only in their His and Tyr contents. Circular dichroism spectroscopy profiles showed pH conformation changes of each component. The thermograms of the different whey protein components showed a higher heat resistance of beta-lactoglobulin A compared to beta-lactoglobulin B at pH 2, and indicated high instability of ovine alpha-lactalbumin at this pH.     

Characterization of ZrOxCyHz thin films deposited by MMP–DECR reactor using Zirconium Tert-Butoxide/O2 mixture

Thin films are deposited in a multipolar microwave plasma reactor excited by distributed electron cyclotron resonance (MMP–DECR) using Zirconium Tert-Butoxide (ZTB) as precursor and characterized in function of two process parameters: microwave power and ratio gas mixture (O₂/ZTB + O₂). Their influences on deposition rate, density, chemical bonds, atomic composition and microstructure of the deposits are presented: for pure ZTB plasma the films contain a high rate of hydrocarbon and their density is low (close to hydrogenated carbon film density). The study versus microwave power shows that film contains less hydrocarbon at high power than at low power but the addition of O₂ to ZTB appears to be mainly responsible for hydrocarbon removal. Moreover microstructure analysis shows a columnar growth when a high amount of O₂ (≥ 90%) is added in the gas mixture.     

Evaluation of contaminant removal of reverse osmosis and advanced oxidation in full-scale operation by combining passive sampling with chemical analysis and bioanalytical tools

Advanced water treatment of secondary treated effluent requires stringent quality control to achieve a water quality suitable for augmenting drinking water supplies. The removal of micropollutants such as pesticides, industrial chemicals, endocrine disrupting chemicals (EDC), pharmaceuticals, and personal care products (PPCP) is paramount. As the concentrations of individual contaminants are typically low, frequent analytical screening is both laborious and costly. We propose and validate an approach for continuous monitoring by applying passive sampling with Empore disks in vessels that were designed to slow down the water flow, and thus uptake kinetics, and ensure that the uptake is only marginally dependent on the chemicals' physicochemical properties over a relatively narrow molecular size range. This design not only assured integrative sampling over 27 days for a broad range of chemicals but also permitted the use of a suite of bioanalytical tools as sum parameters, representative of mixtures of chemicals with a common mode of toxic action. Bioassays proved to be more sensitive than chemical analysis to assess the removal of organic micropollutants by reverse osmosis, followed by UV/H?O? treatment, as many individual compounds fell below the quantification limit of chemical analysis, yet still contributed to the observed mixture toxicity. Nonetheless in several cases, the responses in the bioassays were also below their quantification limits and therefore only three bioassays were evaluated here, representing nonspecific toxicity and two specific end points for estrogenicity and photosynthesis inhibition. Chemical analytical techniques were able to quantify 32 pesticides, 62 PCPPs, and 12 EDCs in reverse osmosis concentrate. However, these chemicals could explain only 1% of the nonspecific toxicity in the Microtox assay in the reverse osmosis concentrate and 0.0025% in the treated water. Likewise only 1% of the estrogenic effect in the E-SCREEN could be explained by the quantified EDCs after reverse osmosis. In comparison, >50% of the estrogenic effect can typically be explained in sewage. Herbicidal activity could be fully explained by chemical analysis as the sampling period coincided with an illegal discharge and two herbicides dominated the mixture effect. The mass balance of the reverse osmosis process matched theoretical expectations for both chemical analysis and bioanalytical tools. Overall the investigated treatment train removed >97% estrogenicity, >99% herbicidal activity, and >96% baseline toxicity, confirming the suitability of the treatment train for polishing water for indirect potable reuse. The product water was indistinguishable from local tap water in all three bioassays. This study demonstrates the suitability and robustness of passive sampling linked with bioanalytical tools for semicontinuous monitoring of advanced water treatment with respect to micropollutant removal.     

N-nitrosamine rejection by reverse osmosis membranes: A full-scale study

This study aims to provide longitudinal and spatial insights to the rejection of N-nitrosamines by reverse osmosis (RO) membranes during sampling campaigns at three full-scale water recycling plants. Samples were collected at all individual filtration stages as well as at a cool and a warm weather period to elucidate the impact of recovery and feed temperature on the rejection of N-nitrosamines. N-nitrosodimethylamine (NDMA) was detected in all RO feed samples varying between 7 and 32 ng/L. Concentrations of most other N-nitrosamines in the feed solutions were determined to be lower than their detection limits (3–5 ng/L) but higher concentrations were detected in the feed after each filtration stage. As a notable exception, in one plant, N-nitrosomorpholine (NMOR) was observed at high concentrations in RO feed (177–475 ng/L) and permeate (34–76 ng/L). Overall rejection of NDMA among the three RO systems varied widely from 4 to 47%. Data presented here suggest that the feed temperature can influence rejection of NDMA. A considerable variation in NDMA rejection across the three RO stages (14–78%) was also observed. Overall NMOR rejections were consistently high ranging from 81 to 84%. On the other hand, overall rejection of N-nitrosodiethylamine (NDEA) varied from negligible to 53%, which was considerably lower than values reported in previous laboratory-scale studies. A comparison between results reported here and the literature indicates that there can be some discrepancy in N-nitrosamine rejection data between laboratory- and full-scale studies probably due to differences in water recoveries and operating conditions (e.g. temperature, membrane fouling, and hydraulic conditions).     

Carboxyl terminated polyamide 12 chain extension by reactive extrusion using a dioxazoline coupling agent. Part II: Effects of extrusion conditions

Condensation reactions between a carboxyl terminated polyamide 12 and a dioxazoline carried out by reactive extrusion have been characterized in the first part of this study. In the present paper, we focus on the influence of extrusion conditions on reaction progress. Influences of screw profile, screw speed, barrel temperature and feed rate have been established. The use of a flow computation software permitted confirmation of the importance of thermal and mechanical degradations in the condensation process.     

On causality, responsibility, and blame in marriage: Validity of the entailment model.

Examined the entailment model of attributions in close relationships (F. D. Fincham and T. N. Bradbury, 1987) using structural equation modeling. In this model, judgments of causality lead to judgments of responsibility, which in turn determine judgments of blame. The sample consisted of 206 married or cohabiting couples who completed the Conflict Rating Scale and the Dyadic Adjustment Scale. The path analysis conducted with LISREL VII supported the value of an entailment conceptualization for both self (women and men) and spouse attributions (men only). As hypothesized, for men the paths among causality, responsibility, blame, and marital adjustment confirmed the mediating role of responsibility and blame attributions. For women, small direct pathways leading to marital satisfaction were found, as well as 2 large indirect pathways specified by the entailment model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

La nature et les corrélats de l'attachement au sein des relations de couple.

Studied the relationship between different styles of attachment (i.e., comforting, avoidant, and anxious-ambivalent) and marital adjustment. Ss were 248 heteresexual adults (mean age 36.7 yrs) who had been married or living together for a mean period of 11 yrs. All Ss completed 2 measures of attachment style and a scale assessing dyadic adjustment. Multiple regression analysis was used to determine interactions between attachment style and marital adjustment, and the convergent validity of the 2 measures of attachment style was analyzed. French versions of the Dyadic Adjustment Scale (G. B. Spanier, 1976) and 2 attachment style questionnaires (C. Hazan and P. R. Shaver, 1987) and (M. Mikulincer et al, 1990) were used. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acetylcholinesterase engineering for detection of insecticide residues

To detect traces of insecticides in the environment using biosensors,we engineered Drosophila acetylcholinesterase (AChE) to increaseits sensitivity and its rate of phosphorylation or carbamoylationby organophosphates or carbamates. The mutants made by site-directedmutagenesis were expressed in baculovirus. Different strategieswere used to obtain these mutants: (i) substitution of aminoacids at positions found mutated in AChE from insects resistantto insecticide, (ii) mutations of amino acids at positions suggestedby 3-D structural analysis of the active site, (iii) Ala-scananalysis of amino acids lining the active site gorge, (iv) mutagenesisat positions detected as important for sensitivity in the Ala-scananalysis and (v) combination of mutations which independentlyenhance sensitivity. The results highlighted the difficultyof predicting the effect of mutations; this may be due to thestructure of the site, a deep gorge with the active serine atthe bottom and to allosteric effects between the top and thebottom of the gorge. Nevertheless, the use of these differentstrategies allowed us to obtain sensitive enzymes. The greatestimprovement was for the sensitivity to dichlorvos for whicha mutant was 300-fold more sensitive than the Drosophila wild-typeenzyme and 288 000-fold more sensitive than the electric eelenzyme, the enzyme commonly used to detect organophosphate andcarbamate.