Evaluation of slaughtering methods for turbot with respect to animal welfare and flesh quality

After elaborating a suitable scheme to assess consciousness/unconsciousness of turbot, the effects on fish welfare of commercial and experimental slaughtering techniques were evaluated. Strong adverse reactions and slow loss of clinical reflexes were observed when fish were slaughtered by bleeding without prior anaesthesia. The efficiency of electricity (150 V for 2 s followed by 25 V for 5 min) as a stunning and killing technique was dependent on the current frequency and mode of administration, ie whether the electrical discharge was applied to the head only or throughout the whole body. Finally, percussion of the head with a mechanical device resulted in immediate and permanent loss of all responses and reflexes in all fish tested. Three methods were selected as a result of the preliminary tests (bleeding in ice slurry, whole‐body electrical treatment and percussion), and their influence on flesh quality was studied over a 9 day period. Fish killed by percussion were characterised by a higher pH and higher water content in the very early stage of post mortem storage, but also by a much delayed rigor mortis. In contrast, fish killed by electricity entered most rapidly into rigor mortis; their flesh was significantly softer (p < 0.05) throughout the entire storage time and was also redder and darker, as indicated by higher a* values (p < 0.001) and lower L* values (p < 0.01) respectively. It is suggested that automated percussion is a suitably humane method for the slaughter of farmed turbot. © 2002 Society of Chemical Industry     

A physiologically plausible spatio-temporal model for EEG signals recorded with intracerebral electrodes in human partial epilepsy

Stereoelectroencephalography (depth-EEG signals) is a presurgical investigation technique of drug-resistant partial epilepsy, in which multiple sensor intracerebral electrodes are used to directly record brain electrical activity. In order to interpret depth-EEG signals, we developed an extended source model which connects two levels of representation: (1) a distributed current dipole model which describes the spatial distribution of neuronal sources; (2) a model of coupled neuronal populations which describes their temporal dynamics. From this extended source model, depth-EEG signals were simulated from the forward solution at each electrode sensor located inside the brain. Results showed that realistic transient epileptiform activities (spikes) are obtained under specific conditions in the model in terms of degree of coupling between neuronal populations and spatial extent of the source. In particular, the cortical area involved in the generation of epileptic spikes was estimated to vary from 18 to 25 cm2, for brain conductivity values ranging from 30 to 35 x 10(-5) S/mm, for high coupling degree between neuronal populations and for a volume conductor model that accounts for the three main tissues of the head (brain, skull, and scalp). This study provides insight into the relationship between spatio-temporal properties of cortical neuronal sources and depth-EEG signals.     

Exhaustive test sets for algebraic specifications

In the context of testing from algebraic specifications, test cases are ground formulas chosen amongst the ground semantic consequences of the specification, according to some possible additional observability conditions. A test set is said to be exhaustive if every programme P passing all the tests is correct and if for every incorrect programme P, there exists a test case on which P fails. Because correctness can be proved by testing on such a test set, it is an appropriate basis for the selection of a test set of practical size. The largest candidate test set is the set of observable consequences of the specification. However, depending on the nature of specifications and programmes, this set is not necessarily exhaustive. In this paper, we study conditions to ensure the exhaustiveness property of this set for several algebraic formalisms (equational, conditional positive, quantifier free and with quantifiers) and several test hypotheses. Copyright © 2016 John Wiley & Sons, Ltd.     

Heavy metal removal from water using the metallogelation properties of a new glycolipid biosurfactant

Water pollution by heavy metals is a problem in both western and developing countries. Heavy metal pollution can be associated with human activity, such as wastewaters from processing of ore mining, but also to simple contamination from metal-rich soils. Whichever the case, chemical and physical methods are generally employed to depollute water. Since most chemicals are themselves polluting agents, there is an increasing interest in finding biobased and biodegradable alternative chemicals, both efficient in removing metals and benign to the environment. Biosurfactants are green chemicals produced by fermentation of yeasts and bacteria and with a good environmental score. Among many applications, this class of compounds has been used to remove heavy metals from contaminated soils. Within this framework, we propose a new mechanism of depolluting water using a glucolipid biosurfactant, G-C18:1, composed of glucose (G) and a C18:1 fatty acid (oleic acid). This compound is able to form a metallogel by complexing cations in water, thus trapping heavy metals (Cu²⁺, Ni²⁺, Cr²⁺, and Co²⁺) in the gel phase. This mechanism allows to remove up to 95% for cobalt and 88 ± 10%, 80 ± 3%, and 59 ± 6% for Cu²⁺, Ni²⁺, and Cr²⁺, respectively. A dedicated structural study shows that this is possible because positively charged species induce gelation of G-C18:1 through a micelle-to-wormlike phase transition, most likely driven by a charge neutralization process. This work shows that wise control of the nanoscale properties of green chemicals can strongly benefit to develop a sustainable future.     

Iron and steel corrosion mechanisms in a carbonate rich pore water: Multiscale characterization of the corrosion product layers

Corrosion experiments were performed on a ferrito-pearlitic (P285-NH) and a ferritic steel (Armco) in a synthetic solution representing the Callovo-Oxfordian porewater during a month at 120°C. Corrosion product layers (CPLs) were characterized from micro to nanoscale in terms of morphology (electron microscopies), composition (energy dispersive X-ray spectroscopy), and structure (µ-Raman, selected area electron diffraction). Both systems present a Ca-siderite bilayer which interface locates the metal original surface, and nano to micrometric magnetite islets on the internal carbonated layer and at the M/CPL interface. The impact of cementite is highlighted in terms of morphology of the CPL and corrosion mechanism.     

Do sewage treatment plant discharges substantially impair fish reproduction in polluted rivers?

Sewage treatment plants are frequently associated with the release of xenobiotics and, consequently, with alterations of the reproductive function induced by many of these substances in aquatic organisms. In order to assess the impacts of sewage treatment plant (STP) discharges in polluted rivers, two sentinel species (gudgeon Gobio gobio and stoneloach Barbatula barbatula) were caught during their reproductive cycle upstream and downstream two STPs (STP1--Goffontaine, STP2--Wegnez). Gonadosomatic index, histological (testicular and ovarian stages, atretic follicles, intersexuality) and endocrine (sex steroids, aromatase activity, alkali-labile phosphorus) parameters were assayed. In brief, the results revealed no systematic significant differences (p<0.05) between upstream and downstream sites, whatever the STP, species or sampling period. However, stoneloach females displayed some signs of reproductive impairment and endocrine disruption downstream STP1 (reduced GSI, oocyte diameter and ALP concentrations, increased proportion of atretic follicles) and STP2 (changes in gonadal aromatase activity and plasma levels of 11-KT and T). Few significant changes were observed for gudgeon males and females while there were no significant differences between upstream and downstream sites for stoneloach males. Moreover, plasma E(2) concentrations recorded in gudgeon males sampled in all sites were as high as in females and this was confirmed by high ALP levels. Besides, spermatogenesis of gudgeon males was delayed in STP1 upstream and downstream sites compared to the corresponding sites in STP2. These observations for gudgeon males do not seem related to STP discharge but to a probable estrogenicity of the river. Therefore, as shown by the results, stoneloach seemed more sensitive than gudgeon to STP discharges. In the present study, sewage treatment plant discharges do not substantially impair fish reproduction. In this respect, caution is required when generalising negative impacts of STP discharges.     

Use of thiolysis hyphenated to RP-HPLC-ESI(-)-MS/MS for the analysis of flavanoids in fresh lager beers

Proanthocyanidins are well known for their involvement in haze and colour development during beer ageing. New methodologies are needed, however, to understand what happens to them in the bottled beer. For the first time in the brewing field, thiolysis was hyphenated to RP-HPLC-ESI(-)-MS/MS to investigate these flavanoids. Thirty minutes at 40 °C followed by 10 h at room temperature emerged as the best conditions for complete depolymerisation. NP-HPLC-ESI(-)-MS/MS was used to quantify and isolate fractions from monomers to trimers in a Sephadex LH20 acetone/water (70/30, v/v) beer extract. Unsurprisingly, a lower dimer/monomer ratio was evidenced in PVPP-treated beers than in silica gel-filtered beers. Most beer dimers are procyanidins B3 (two catechin units) whilst most trimers are prodelphinidins (catechin in terminal units and gallocatechins or catechins in extension units). Gallocatechin appeared to come mainly from malt. Despite the absence of chromatographic peaks corresponding to oligomers above trimers, an apparent degree of polymerisation close to six was calculated in the total LH20 extract. Still higher mean degrees of polymerisation (mDPs) were calculated for malt and hop, indicating selective extraction or depolymerisation from raw materials to beer. The main part of beer polyphenols is composed of complex undefined structures not degraded by toluene-α-thiol.     

A Modelling Solution for Developing and Evaluating Agricultural Land-Use Scenarios in Water Scarcity Contexts

To meet sustainability challenges, regional water management and planning require approaches that assess the land-use visions of various stakeholders using their own evaluation criteria. Models and information systems are keystones in such integrated assessment activities. SPACSS (the SPAtial Cropping System Scenarios builder and evaluator) is a modelling solution that aims to help decision-makers evaluate normative land-use scenarios. A prototype of SPACSS was developed to explore concerns raised by a dam-building project in south-western France, specifically the relation between cropping system distribution and water uptake. This paper presents the initial steps of SPACSS development by scientists and agricultural experts and its evaluation by users through alternative scenarios of maize cropping (altering either its precocity or management to reduce irrigation). SPACSS can represent a wide range of land-use scenarios and aggregate impact indicators at several spatial and temporal scales. Although SPACSS served as a solid support for discussions with stakeholders and decision-makers, it needs modifications to represent more realistic, and thus more complex, land-use scenarios. These modifications will make SPACSS potentially valuable for dealing with a variety of issues concerning agricultural landscapes, far beyond the single question of quantitative water management.