Cooperative localization techniques for wireless sensor networks: free,signal and angle based techniques

This paper addresses the problem of localization in sensor networks where, initially, a certain number of sensors are aware of their positions (either by using GPS or by being hand‐placed) and are referred to as anchors. Our goal is to localize all sensors with high accuracy, while using a limited number of anchors. Sensors can be equipped with different technologies for signal and angle measurements. These measures can be altered by some errors because of the network environment that induces position inaccuracies. In this paper, we propose a family (AT‐Family) of three new distributed localization techniques in wireless sensor networks: free‐measurement (AT‐Free) where sensors have no capability of measure, signal‐measurement (AT‐Dist) where sensors can calculate distances, and angle‐measurement (AT‐Angle) where sensors can calculate angles. These methods determine the position of each sensor while indicating the accuracy of its position. They have two important properties: first, a sensor node can deduce if its estimated position is close to its real position and contribute to the positioning of others nodes; second, a sensor can eliminate wrong information received about its position. This last property allows to manage measure errors that are the main drawback of measure‐based methods such as AT‐Dist and AT‐Angle techniques. By varying the density and the error rate, simulations show that the three proposed techniques achieve good performances in term of high accuracy of localized nodes and less energy consuming while assuming presence of measure errors and considering low number of anchors. Copyright © 2012 John Wiley & Sons, Ltd.     

Lipid Oxidation in Oil‐in‐Water Emulsions: Involvement of the Interfacial Layer

More polyunsaturated fats in processed foods and fewer additives are a huge demand of public health agencies and consumers. Consequently, although foods have an enhanced tendency to oxidize, the usage of antioxidants, especially synthetic antioxidants, is restrained. An alternate solution is to better control the localization of reactants inside the food matrix to limit oxidation. This review establishes the state‐of‐the‐art on lipid oxidation in oil‐in‐water (O/W) emulsions, with an emphasis on the role of the interfacial region, a critical area in the system in that respect. We first provide a summary on the essential basic knowledge regarding (i) the structure of O/W emulsions and interfaces and (ii) the general mechanisms of lipid oxidation. Then, we discuss the factors involved in the development of lipid oxidation in O/W emulsions with a special focus on the role played by the interfacial region. The multiple effects that can be attributed to emulsifiers according to their chemical structure and their location, and the interrelationships between the parameters that define the physicochemistry and structure of emulsions are highlighted. This work sheds new light on the interpretation of reported results that are sometimes ambiguous or contradictory.     

Nutritional value and digestion rate of rhea meat proteins in association with storage and cooking processes

The nutritional value of proteins was investigated after the storage and cooking of rhea M. Gastrocnemius pars interna. Oxidation of basic and aromatic amino acids, surface hydrophobicity and aggregation state of proteins, were determined in raw and cooked meat. In addition, myofibrillar proteins were exposed in vitro to proteases of the digestive tract. Cooking markedly affected the protein surface hydrophobicity. The BBP bound content was three times greater in cooked than in fresh rhea meat. A small increment in tryptophan content after cooking was observed. Storage influenced Schiff bases formation indicating the presence of protein-aldehyde adducts after cooking. High content of Schiff bases was found after cooking of samples stored for 5 days, demonstrating a probable implication of free amino groups, most likely from lysine. Cooking decreased the myofibrillar protein susceptibility to pepsin activity. After cooking, the proteolysis rate by pancreatic enzymes increased. Our findings support the importance of protein aggregation in the nutritional value of meat proteins.     

Combination of mass spectrometry and site-specific NMR isotope analyses in the characterisation of amino acids

Experimental strategies have been developed which make amino acid probes accessible to the NMR study of site-specific natural isotope fractionation. A multi-isotope approach, based on combined mass spectrometry determination of hydrogen-, carbon- and nitrogen-overall isotope contents and on ²H-NMR determination of site-specific hydrogen isotope ratios, shows that relatively wide ranges of variation are exhibited by the isotopic parameters of glutamic acid, aspartic acid, alanine, proline and lysine samples from different origins. Moreover, relatively large deviations with respect to a random distribution of deuterium among the molecular sites are quantified and compared. A noticeable enantiomeric imbalance at the methylenic site adjacent to the chiral centre is also detected in natural samples of L -glutamic and L -aspartic acids in particular. The results are analysed in terms of filiation criteria and technological effects. It is shown in particular that the C₃ or C₄ metabolic origin of the raw materials utilised in fermentation processes can be recognised. Principal component analyses involving the two mean isotopic variables δ¹³C and δ¹⁵N and the three site-specific variables (D/H)_x (D/H)_β and (D/H)_γ associated with positions α, β and γ of glutamic acids, for example, are helpful for interpreting the main discriminating factors. This approach provides the basis for new applications to origin recognition of fundamental constituents and metabolites of plant or animal species.     

Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities

Abstract: GC‐FID and GC‐MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p‐cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC₅₀= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC₅₀= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC₅₀ of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.     

Ady2p is essential for the acetate permease activity in the yeast Saccharomyces cerevisiae

To identify new genes involved in acetate uptake in Saccharomyces cerevisiae, an analysis of the gene expression profiles of cells shifted from glucose to acetic acid was performed. The gene expression reprogramming of yeast adapting to a poor non-fermentable carbon source was observed, including dramatic metabolic changes, global activation of translation machinery, mitochondria biogenesis and the induction of known or putative transporters. Among them, the gene ADY2/YCR010c was identified as a new key element for acetate transport, being homologous to the Yarrowia lipolytica GPR1 gene, which has a role in acetic acid sensitivity. Disruption of ADY2 in S. cerevisiae abolished the active transport of acetate. Microarray analyses of ady2Delta strains showed that this gene is not a critical regulator of acetate response and that its role is directly connected to acetate transport. Ady2p is predicted to be a membrane protein and is a valuable acetate transporter candidate.     

Categorization processes in mental comparisons.

Five experiments explore categorization and category-based congruity effects in mental comparisons. The first 4 experiments concentrate on categorization of infinite-set small items. The experiments vary the additional items presented and whether those items appear once (Experiments 1-2) or repeatedly (Experiments 3-4). Additional items include other small items (Experiment 1), relatively large items (Experiments 2-4), and items involving nonsize dimensions (Experiment 4). The critical small items show a complete congruity effect only in Experiments 1 and 3. Results suggest that categorization of infinite-set items may be based on range information alone (Experiment 1) but that multiple categorizations based on multiple ranges (Experiment 2) may require attentional effort. Results implicate categorization as a central process in mental comparison, despite differences in ease of categorization across paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE ADAPTABILITY OF THE FRENCH ARMAMENTS INDUSTRY IN AN ERA OF GLOBALIZATION

The transformations of the French arms industry have to be put in the context of the dramatic changes in the geopolitical and economic environment, or globalization. This paper documents the role of military-related technological programs in French technology policy, and their contribution to the technological performance of defense contractors and manufacturing industry generally. It employs the concept of a French Meso-system of Armaments (FMSA) to describe the set of committed governmental organizations and industrial companies, which are bound up with each other through market and non-market relationships. The paper traces the main transformations of the FMSA that aim at preserving, through adaptation, the intertwined relationships between the state and defense companies over the past decades and in particular in the decade following the collapse of the communist system.