Lipid damage during frozen storage of Gadiform species captured in different seasons

Quality loss of two gadiform fish species (blue whiting, Micromesistius poutassou; hake, Merluccius merluccius) during frozen storage (–30 and –10 °C; up to 12 months) was studied. For this, hydrolytic (formation of free fatty acids, FFA) and oxidative (conjugated dienes, peroxide and interaction compound formation) lipid damage were analysed. For both species, individual fishes captured in two different trials (May and November) were considered. Increasing (p <0.05) lipid hydrolysis and oxidation (peroxide and interaction compound formation) were observed for all kinds of samples throughout the frozen storage. Interaction compound detection by fluorescence analysis showed the best correlation values with storage time. Some higher (p <0.05) hydrolysis development could be observed in hake captured in May than in its counterpart from the November trial, while frozen blue whiting did not provide definite differences for FFA formation between both trials. Concerning peroxide formation, higher (p <0.05) values were obtained for individual blue whiting and hake captured in November when compared to their corresponding May fish for both frozen storage conditions. Interaction compound formation was also found to be higher (p <0.05) for November hake fish than for its counterpart captured in May, while blue whiting did not provide definite differences between trials.     

The French-speaking ergonomists' approach to work activity: cross-influences of field intervention and conceptual models

French-speaking ergonomists generally consider the concept of activity to be central in their approach to work and to changing it. However, their understanding of the term developed in a specific context, combining the influence of Soviet psychology with that of other forms of thinking already developed in France. Since then, the notion has received considerable input. The concept of activity as it has been developed in French-speaking countries (and thereafter in others like Brazil as it has spread) is not exactly identical to that developed by Engeström, even if there are obviously many common points. The aim of this article is not to make a systematic international comparison of approaches all referring to the concept of activity. Rather, the author's objective is limited to explaining the emergence of the concept as it is taught in France with its theoretical and methodological consequences. The reader should, therefore, not be unduly surprised by the focus on French-speaking ergonomists; this is not testimony to ignorance of the international literature, but constitutes the specific nature of this essay. If other authors attempt a similar clarification of thought at a later date, it will be easier for the international ergonomic community to distinguish the resemblances and differences between the approaches on an international level.     

Heterogeneous Transformation of Glycerol to Lactic Acid

Significant yields of lactic acid (LA) are obtained during the treatment of glycerol solution under inert gas with supported metallic catalysts under basic conditions. The nature of the atmosphere and the metal affected the activity and the selectivity of the reaction. Iridium-based catalysts are efficient for LA synthesis.     

Incorporating preventive maintenance into the m-machine no-wait flow-shop scheduling problem with total flow-time minimization: a computational study

In this article, the impact of preventive maintenance policies on the constructive heuristics performance for the no-wait flow-shop problem with total flow-time minimization is evaluated. The main constructive heuristics for the m-machine no-wait flow-shop scheduling problem with total flow-time minimization are compared through computational experiments with a set of 5760 problems. The results show that the adopted parameters significantly affect the performance of the constructive heuristics; also, the computational effort required to solve the problems increases owing to the complexity of the function-objective calculation. Heuristics proposed by Laha and Sapkal (LSH) and Framinan, Nagano and Moccellin (FNMH) provide the best solutions for both evaluated policies.     

DEM modelling for flow of cohesive lignocellulosic biomass powders: Model calibration using bulk tests

Biomass feeding problems greatly hinder the industrialization of entrained-flow gasification systems for production of 2nd generation biofuels. Appropriate DEM modelling could allow engineers to design solutions that overcome these flow problems. This work shows the application of a DEM calibration framework to produce a realistic, calibrated and efficient material model for lignocellulosic biomass. A coarse (500–710?µm) and a fine (200–315?µm) sieving cut of milled poplar were used in this study. The elongated shape and the cohesive behavior were respectively simulated using a coarse-grained multisphere approach and a cohesive SJKR contact model. Measurements of three physical responses (angle-of-repose, bulk density, a retainment ratio) allowed calibration of the sliding (µ_s) and rolling friction (µ_r) coefficients and the cohesion energy density (CED). Using a statistical analysis, the most influential calibration parameters for each bulk response were identified. A Non-Dominated Sorting Genetic Algorithm was used to solve the calibration multi-objective optimization problem. Several sets of optimal solutions reproduced accurately the three physical responses and the experimental shear responses were closely reproduced by simulations for the population of coarse particles. The DEM calibration framework studied here aims to produce material models useful for assessing flow behavior and equipment interaction for biomass particles.     

Analyzing the physiological signature of anabolic steroids in cattle urine using pyrolysis/metastable atom bombardment mass spectrometry and pattern recognition

Pyrolysis coupled to metastable atom bombardment (MAB) and time-of-flight mass spectrometry (TOFMS) is used for generating mass spectra from bovine urine samples obtained from cattle treated with anabolic steroids. These spectra constitute fingerprints, which can be discriminated by multivariate statistical analysis. Four main conclusions can be drawn from this work: (i) The use of different metastable gases, such as Xe*, Kr*, or N2*, as an energy-tunable ionization beamline allows control of the internal energy and the dissociation processes of the produced odd electron molecular ions, thus giving rise to complementary mass spectra fingerprints. (ii) A variable transformation depending on the biofluid matrix suitably contracts the frequency distribution of the generated data for low m/z ratios holding information related to endogenous metabolites encountered in urine. (iii) Coupling variable selection to statistical pattern recognition methods results in low error rates (< 1%) for predicting MAB mass fingerprints, especially using lineardiscriminant analysis (LDA). (iv) LDA discriminates controls from treated animals and also correlates to quantitative physiological responses induced by anabolic steroids. This work shows that Py-MAB-TOFMS could be a suitable method for complementary monitoring anabolic use in sports, medicine, and cattle breeding, as well as monitoring many other long-lasting although weak physiological disruptions.