Utilisation des réseaux de neurones récurrents à temps continu dans le contexte d'une interaction sensorimotrice temps réel minimaliste crédible

Ce stage aspire à utiliser une architecture cognitive afin de créer un programme capable d'interagir gestuellement en 2D avec un humain et de se faire passer pour tel. Le but étant de comprendre les mécanismes d'obtention de la crédibilité par les agents de réalité virtuelle lors d'interactions gestuelles minimalistes. Une étude des différentes architectures existantes nous permet de retenir les CTRNN comme étant la plus prometteuse. On paramètre ceux-ci à l'aide d'algorithmes génétiques, en visant à promouvoir deux aspects : le réalisme des mouvements et la qualité de l'interaction avec l'humain. Le programme est ensuite testé au cours d'expérimentations. L'exploitation des résultats, à la fois pour évaluer le protocole et le sentiment de crédibilité obtenu par nos agents, est ensuite présentée

Ultrastructural Aspects of Spun Pea and Fababean Proteins

The ultrastructure of pea and fababean spun proteins has been studied by SEM and TEM as a function of dope pH and washing bath salt concentrations. The textural properties {mechanical resistance, moisture content) and diameter of the fibres have been determined. Spinning was only possible when dope pH was higher than 11. An increase in dope pH from 11.5 to 13 induced a shear strength increase whereas the moisture content and the diameter of the fibres decreased . The structure of the fibres became more compact and changed from an aggregate of spherical particles to a tridimensional network. When dope pH was equal to 12. 6, the increase in washing bath salt content from 2 to 10 % NaCl produced more compact fibres. At high dope pH, the protein aggregates were dissociated and the polypeptide chains were unfolded, which favoured the lining up of the macromolecules during the spinning process and increased the protein -protein interactions in the fibres. High salt concentration in the washing baths produced a salting out effect which probably also enhanced the chain-chain interactions. Contrary to previous studies, protein strand orientation along the fibre axis and a double cortex-core structure have been demonstrated

Sähkökemiallisesti valmistetut molekyylimallitetut polymeerit epäpuhtauksien detektoinnissa

New electrochemical molecularly imprinted polymers (e-MIPs) for benzo(a)pyrene (BaP) based on vinylferrocene (VFc) as redox tracer directly integrated into binding cavities during polymerization with crosslinker are reported. Impacts on the BaP detection are discussed according to: 1) the addition or no of 4-vinylpyridine (4VP) as comonomer, 2) the use of ethylene glycol dimethacrylate (EDMA) or divinylbenzene (DVB) as crosslinker. After characterization, these new e-MIPs and their corresponding non-imprinted polymers (e-NIPs) were incorporated in carbon paste electrodes and measurements were carried out by square wave voltammetry. All analyses revealed that e-MIP based on VFc and EDMA is the best to detect the template, with an imprinting factor of 7.3 and a LOD of 0.93 mu mol/L of BaP.Peer reviewe

Sterols from the brown alga Cystoseira foeniculacea: Degradation of fucosterol into saringosterol epimers

AbstractThe present study was carried out in order to determine the phytochemical composition of the marine brown alga Cystoseira foeniculacea collected off the coasts of Algeria. After a preliminary fractionation of its organic crude extracts by column chromatography, the resulting fractions were further analysed by 1H NMR. Even though algal species of the genus Cystoseira are commonly known to produce a wide variety of meroditerpenoids, in the case of C. foeniculacea none of the fractions were found to contain such compounds: most of the fractions showed typical 1H NMR signals of fatty acids and derivatives (mainly glycerolipids and glycolipids). Nevertheless, the thorough analysis of a sterol-enriched fraction by RP-C8 HPLC led to the isolation, for the first time from this species, of fucosterol (1) and a mixture of saringosterols (2 and 3). The NMR data of compounds 1–3 were fully determined with the help of 1D and 2D experiments which allowed the reassignment of some attributions in comparison with those reported in the literature. This work also confirms evidence of the oxidative degradation of fucosterol into a C-24 epimeric mixture of saringosterols

Allelopathic interactions between the brown algal genus Lobophora (Dictyotales, Phaeophyceae) and scleractinian corals

Allelopathy has been recently suggested as a mechanism by which macroalgae may outcompete corals in damaged reefs. Members of the brown algal genus Lobophora are commonly observed in close contact with scleractinian corals and have been considered responsible for negative effects of macroalgae to scleractinian corals. Recent field assays have suggested the potential role of chemical mediators in this interaction. We performed in situ bioassays testing the allelopathy of crude extracts and isolated compounds of several Lobophora species, naturally associated or not with corals, against four corals in New Caledonia. Our results showed that, regardless of their natural association with corals, organic extracts from species of the genus Lobophora are intrinsically capable of bleaching some coral species upon direct contact. Additionally, three new C-21 polyunsaturated alcohols named lobophorenols A-C (1-3) were isolated and identified. Significant all elopathic effects against Acropora muricata were identified for these compounds. In situ observations in New Caledonia, however, indicated that while allelopathic interactions are likely to occur at the macroalgal-coral interface, Lobophora spp. rarely bleached their coral hosts. These findings are important toward our understanding of the importance of allelopathy versus other processes such as herbivory in the interaction between macroalgae and corals in reef ecosystems

Effect of transport length on in vivo oxidative status and breast meat characteristics in outdoor-reared chicken genotypes

The aim of the study was to evaluate the effect of transport length on in vivo oxidative status and breast meat characteristics in two chicken genotypes reared under free range conditions. A total of 200 male chicks, 100 from fast-growing (Ross 308) and 100 from medium-growing (Naked Neck) strain were used. Fifty-six of these, 28 for genotype, before slaughtering, were randomly allocated to 2 pre-slaughter conditions: absence (0 h) or 4 h of transport. The transport length significantly affected the in vivo oxidative status of broiler greatly reducing the α and δ-tocopherol, retinol and lutein + zeaxanthin content of plasma, and increased the oxidative stress (thiobarbituric acid reactive substances, TBARS) in both strains. Concerning meat quality, the pH (0, 2 and 24 h post-mortem) of breast muscles of chickens transported for 4 h, showed higher values, and respect to strains, Naked Neck had lower values. The pH values were negatively correlated with the lightness (2–24 h) and the shear force of meat. The transport length significantly affected the fatty acid profile of breast muscle, with a decrease in polyunsaturated fatty acids and an increase in TBARS value. Even the antioxidants content of breast was reduced by chicken transport (α-tocotrienol, α-, δ-tocopherol and lutein + zeaxanthin), especially in Naked Neck birds. In conclusion, the results indicate that transport for 4 h prior to slaughter, negatively affect the meat quality of poultry. Slow-growing chickens seem more sensible to stress transport due to the higher kinetic behaviour of these strains

Posidonia oceanica restoration, a relevant strategy after boat anchoring degradation?

Trabajo presentado al 7th Mediterranean Symposium on Marine Vegetation, celebrado en Génova (Italia), los días 19 y 20 de septiembre de 2022.The anchoring of large pleasure boats constitutes one of the main threats in shallow marine habitats and particularly for seagrass beds. In the Mediterranean, this activity has seen constant development during the last decades, causing major physical disturbances in Posidonia oceanica meadows and associated ecosystem services, notably in terms of climate change mitigation (i.e. carbon fixation and sequestration capacities). In this context, the aims of the present study are to estimate the impact of these anchoring activities on P. oceanica meadows in a particularly highlyfrequented area (Sant’Amanza gulf, SE Corsica Island) and to set up a strategy to restore this major carbon sink. Since the last decade, time-series of marine habitat maps revealed an important regression of P. oceanica meadows, with a loss of 72.9 ha, corresponding to 11% of the meadow surface and 9% decline in the total carbon fixation and sequestration performed each year. Moreover, in the most impacted part of the bay (Balistra bay), a loss of 16.6 ha (28%) has been recorded between 2011 and 2022. Following recent enforcement of anchoring regulation, prohibiting the anchoring of large units (greater than 24 m), and the lockdown linked to the COVID-19 pandemic, anchorages in the seagrass reduced by 92%, between 2018 and 2022. Natural recovery was observed at the edge of the meadow (plagiotropic rhizomes) but this growth is slow and the areas to recover are large. As a result, a transplant experiment, from cuttings harvested from the adjacent meadows, was initiated in the spring 2021. Four restoration techniques are being tested in the some pilot sites and the development of these transplants will be monitored and compared to the natural recovery.This research has been co-financed by INTERREG program (GIREPAM), Collectivity of Corsica Corse (PADDUC-CHANGE), SETEC Foundation, Environment Office of Corsica and the French Office of Biodiversity (RenforC program)

An ecosystem-based approach to assess the status of Mediterranean algae-dominated shallow rocky reefs.

A conceptual model was constructed for the functioning the algae-dominated rocky reef ecosystem of the Mediterranean Sea. The Ecosystem-Based Quality Index (reef-EBQI) is based upon this model. This index meets the objectives of the EU Marine Strategy Framework Directive. It is based upon (i) the weighting of each compartment, according to its importance in the functioning of the ecosystem; (ii) biological parameters assessing the state of each compartment; (iii) the aggregation of these parameters, assessing the quality of the ecosystem functioning, for each site; (iv) and a Confidence Index measuring the reliability of the index, for each site. The reef-EBQI was used at 40 sites in the northwestern Mediterranean. It constitutes an efficient tool, because it is based upon a wide set of functional compartments, rather than upon just a few species; it is easy and inexpensive to implement, robust and not redundant with regard to already existing indices

Antiprotozoal Activities of Organic Extracts from French Marine Seaweeds

Marine macrophytes contain a variety of biologically active compounds, some reported to have antiprotozoal activity in vitro. As a part of a screening program to search for new natural antiprotozoals, we screened hydroalcoholic and ethyl acetate extracts of 20 species of seaweeds from three phyla (Rhodophyta, Heterokontophyta and Chlorophyta), sampled along the Normandy (France) coast. We tested them in vitro against the protozoa responsible for three major endemic parasitic diseases: Plasmodium falciparum, Leishmania donovani and Trypanosoma cruzi. The selectivity of the extracts was also evaluated by testing on a mammalian cell line (L6 cells). Ethyl acetate extracts were more active than hydroalcoholic ones. Activity against T. cruzi and L. donovani was non-existent to average, but almost half the extracts showed good activity against P. falciparum. The ethyl acetate extract of Mastocarpus stellatus showed the best antiplasmodial activity as well as the best selectivity index (IC50 = 2.8 μg/mL; SI > 30). Interestingly, a red algae species, which shares phylogenetic origins with P. falciparum, showed the best antiplasmodial activity. This study is the first to report comparative antiprotozoal activity of French marine algae. Some of the species studied here have not previously been biologically evaluated