2,173 research outputs found
Le droit des contrats : outil de sécurité alimentaire dans le commerce et les investissements internationaux ?
Chapitre de l’ouvrage collectif Penser une démocratie alimentaire Volume II – Proposition Lascaux entre ressources naturelles et besoins fondamentaux, F. Collart Dutilleul et T. Bréger (dir), Inida, San José, 2014, pp. 357-364International audienceLa sécurité alimentaire des pays du Nord n’est pas celle des pays du Sud. Aux objectifs de diversité, de qualité des produits, d’information et de santé des consommateurs des premiers, répondent des préoccupations vitales d’autosuffisance alimentaire des seconds, traversant la propriété des terres, leurs cultures, l’approvisionnement en produits agroalimentaires et en intrants. Dès lors, les échanges commerciaux et les investissements internationaux dont les objets sont ces biens particuliers que sont la terre agricole et l’aliment, répondent à des objectifs inéluctablement différents, dont on sait qu’ils ne permettent pas pour l’essentiel, d’assurer l’effectivité du droit à l’alimentation, droit subjectif pourtant fondamental. Par ailleurs, au-delà de cette préoccupation essentielle, il peut s’avérer intéressant de s’interroger sur les outils contractuels qui régissent ces rapports économiques. S’il est bien un domaine dans lequel le sacro-saint principe de sécurité juridique n’est pas ébranlé, c’est celui des échanges agroalimentaires internationaux. Cependant, c’est paradoxalement à cet endroit qu’il est utile d’engager quelques réflexions
Robust Visual Sim-to-Real Transfer for Robotic Manipulation
Learning visuomotor policies in simulation is much safer and cheaper than in
the real world. However, due to discrepancies between the simulated and real
data, simulator-trained policies often fail when transferred to real robots.
One common approach to bridge the visual sim-to-real domain gap is domain
randomization (DR). While previous work mainly evaluates DR for disembodied
tasks, such as pose estimation and object detection, here we systematically
explore visual domain randomization methods and benchmark them on a rich set of
challenging robotic manipulation tasks. In particular, we propose an off-line
proxy task of cube localization to select DR parameters for texture
randomization, lighting randomization, variations of object colors and camera
parameters. Notably, we demonstrate that DR parameters have similar impact on
our off-line proxy task and on-line policies. We, hence, use off-line optimized
DR parameters to train visuomotor policies in simulation and directly apply
such policies to a real robot. Our approach achieves 93% success rate on
average when tested on a diverse set of challenging manipulation tasks.
Moreover, we evaluate the robustness of policies to visual variations in real
scenes and show that our simulator-trained policies outperform policies learned
using real but limited data. Code, simulation environment, real robot datasets
and trained models are available at
https://www.di.ens.fr/willow/research/robust_s2r/
G x E interactions on yield and quality in Coffea arabica: New F1 hybrids outperform American cultivars
Conventional American cultivars of coffee are no longer adapted to global warming. Finding highly productive and stable cultivars in different environments without neglecting quality characteristics has become a priority for breeders. In this study, new Arabica F1 hybrids clones were compared to conventional American varieties in seven contrasting environments, for yield, rust incidence and volume of the canopy. The quality was assessed through size, weight of 100 beans, biochemical analysis (24 aroma precursors and 31 volatiles compounds) and sensory analysis. Conventional varieties were the least productive, producing 50% less than the best hybrid. The AMMI model analysis pointed out five hybrids as the most stable and productive. Two F1 hybrids clones, H1-Centroamericano and H16-Mundo Maya, were superior to the most planted American cultivar in Latin and Central America showing a high yield performance and stability performance. H1-Centroamerica and Starmaya contain more d-limonene than Caturra, while Starmaya contain more 3-methylbutanoic acid than the control. Those two latter volatiles compounds are linked with good cup quality in previous studies. In terms of sensory analysis, Starmaya and H1-Centroamericano scored better than control
Colloidal semiconductor/magnetic heterostructures based on iron-oxide-functionalized brookite TiO2 nanorods
A flexible colloidal seeded-growth strategy has been developed to synthesize all-oxide semiconductor/magnetic hybrid nanocrystals (HNCs) in various topological arrangements, for which the dimensions of the constituent material domains can be controlled independently over a wide range. Our approach relies on driving preferential heterogeneous nucleation and growth of spinel cubic iron oxide (IO) domains onto brookite TiO2 nanorods (b-TiO2) with tailored geometric parameters, by means of time-programmed delivery of organometallic precursors into a suitable TiO2-loaded surfactant environment. The b-TiO2 seeds exhibit size-dependent accessibility towards IO under diffusion-controlled growth regime, which allows attainment of HNCs individually made of a single b-TiO2 section functionalized with either one or multiple nearly spherical IO domains. In spite of the dissimilarity of the respective crystal-phases, the two materials share large interfacial junctions without significant lattice strain being induced across the heterostructures. The synthetic achievements have been supported by a systematic morphological, compositional and structural characterization of the as-prepared HNCs, offering a mechanistic insight into the specific role of the seeds in the control of heterostructure formation in liquid media. In addition, the impact of the formed b-TiO2/IO heterojunctions on the magnetic properties of IO has also been assessed
The 'invisible hand': regulation of RHO GTPases by RHOGDIs
The 'invisible hand' is a term originally coined by Adam Smith in the Theory of Moral Sentiments to describe the forces of self-interest, competition, and supply and demand that regulate the resources in society. This metaphor continues to be used by economists to describe the self-regulating nature of a market economy. The same metaphor can be used to describe the RHO-specific guanine nucleotide dissociation inhibitor (RHOGDI) family, which operates in the background, as an invisible hand, using similar forces to regulate the RHO GTPase cycle
Charge separation: From the topology of molecular electronic transitions to the dye/semiconductor interfacial energetics and kinetics
Charge separation properties, that is the ability of a chromophore, or a
chromophore/semiconductor interface, to separate charges upon light absorption,
are crucial characteristics for an efficient photovoltaic device. Starting from
this concept, we devote the first part of this book chapter to the topological
analysis of molecular electronic transitions induced by photon capture. Such
analysis can be either qualitative or quantitative, and is presented here in
the framework of the reduced density matrix theory applied to single-reference,
multiconfigurational excited states. The qualitative strategies are separated
into density-based and wave function-based approaches, while the quantitative
methods reported here for analysing the photoinduced charge transfer nature are
either fragment-based, global or statistical. In the second part of this
chapter we extend the analysis to dye-sensitized metal oxide surface models,
discussing interfacial charge separation, energetics and electron injection
kinetics from the dye excited state to the semiconductor conduction band
states
Chicory increases acetate turnover, but not propionate and butyrate peripheral turnovers in rats
Chicory roots are rich in inulin that is degraded into SCFA in the caecum and colon. Whole-body SCFA metabolism was investigated in rats during food deprivation and postprandial states. After 22h of food deprivation, sixteen rats received an IV injection of radioactive 14C-labelled SCFA. The volume of distribution and the fractional clearance rate of SCFA were 0·25-0·27 litres/kg and 5·4-5·9%/min, respectively. The half-life in the first extracellular rapidly decaying compartment was between 0·9 and 1·4min. After 22h of food deprivation, another seventeen rats received a primed continuous IV infusion of 13C-labelled SCFA for 2h. Isotope enrichment (13C) of SCFA was determined in peripheral arterial blood by MS. Peripheral acetate, propionate and butyrate turnover rates were 29, 4 and 0·3μmol/kg per min respectively. Following 4 weeks of treatment with chicory root or control diets, eighteen fed rats received a primed continuous IV infusion of 13C-labelled SCFA for 2h. Intestinal degradation of dietary chicory lowered caecal pH, enhanced caecal and colonic weights, caecal SCFA concentrations and breath H2.The diet with chicory supplementation enhanced peripheral acetate turnover by 25% (P=0·017) concomitant with an increase in plasma acetate concentration. There were no changes in propionate or butyrate turnovers. In conclusion, by setting up a multi-tracer approach to simultaneously assess the turnovers of acetate, propionate and butyrate it was demonstrated that a chronic chicory-rich diet significantly increases peripheral acetate turnover but not that of propionate or butyrate in rat
A site selection methodology for CO2 underground storage in deep saline aquifers: case of the Paris Basin
International audienceSite selection is a fundamental step, which can condition the success of a CO2 geological storage. A CO2 storage has to gather several targets, which can be expressed through a list of criteria. In the proposed site selection methodology, these criteria can be classified into “killer criteria” and “site-qualification criteria”, whose combinations allow identifying potential sites and the most appropriate one(s). This multicriteria methodology is applied on the PICOREF study area, located in the Paris Basin, on which potential site(s) in deep saline aquifers are investigated
Breast reconstruction: a quality measure for breast cancer care?
Parallel to its life-threatening nature, breast cancer can affect physical integrity, having a psychosocial impact on patients. Determining the optimal proportion of patients who should undergo breast reconstruction after cancer surgery represents a complex task. What seems to be unquestionable is that the ability to offer reconstruction and a wide range of surgical options plays an important role in current breast cancer management. The multidisciplinary approach is a paramount aspect not only for a successful oncologic treatment, but also for improving patient quality of life
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