On radiative transfer in water spray curtains using the discrete ordinates method

International audienc

Les systèmes transformants d'une couverture ferrallitique de Guyane française : analyse structurale d'une formation supergène et mode de représentation

Les auteurs présentent une étude détaillée d'un interfluve de Guyane française qui apporte une contribution à la connaissance des systèmes transformants dans les formations supergènes des régions tropicales humides

Line mixing effects in isotropic Raman spectra of pure N2: A classical trajectory study

International audienceLine mixing effects in the Q branch of pure N2 isotropic Raman scattering are studied at room temperature using a classical trajectory method. It is the first study using an extended modified version of Gordon's classical theory of impact broadening and shift of rovibrational lines. The whole relaxation matrix is calculated using an exact 3D classical trajectory method for binary collisions of rigid N2 molecules employing the most up-to-date intermolecular potential energy surface (PES). A simple symmetrizing procedure is employed to improve off-diagonal cross-sections to make them obeying exactly the principle of detailed balance. The adequacy of the results is confirmed by the sum rule. The comparison is made with available experimental data as well as with benchmark fully quantum close coupling [F. Thibault, C. Boulet, and Q. Ma, J. Chem. Phys. 140, 044303 (2014)] and refined semi-classical Robert-Bonamy [C. Boulet, Q. Ma, and F. Thibault, J. Chem. Phys. 140, 084310 (2014)] results. All calculations (classical, quantum and semi-classical) were made using the same PES. The agreement between classical and quantum relaxation matrices is excellent, opening the way to the analysis of more complex molecular systems

Comparison of quantum, semi-classical and classical methods in the calculation of nitrogen self-broadened linewidths

International audienceWe perform dynamical calculations on two robust N2-N2 potential energy surfaces in order to intercompare pressure broadening coefficients derived from close coupling and coupled states quantum dynamical methods, the semi-classical model of Robert and Bonamy and a full classical method. The coupled states and full classical results compare well with the experimental results or with close coupling values when available. This study confirms that the classical method is a good alternative at room and high temperatures to quantum dynamical methods. The results obtained using the semi-classical method however deviate from the other sets of data at all temperatures considered here (77-2400 K)

The ABCD (Agriculture Biologique, Conseil et Développement), a French professional degree in organic farming, consulting and development

The creation of a professional degree in organic farming, known as an ABCD, is the result of the desire to provide training at the national level that is supported by the agriculture sector and that brings together the know-how of universities and higher education institutions specialised in agronomy and those of a network of teaching establishments specialised in technical education in the field. This degree aims at forming agents and advisors capable of working in a wide range of fields such as production, processing, distribution, control-certification and marketing. It is mainly intended for adults interested in career development and students who would like to further their education. Four training sites are involved and all teaching is done through a virtual digital university using information and communication technologies

Experimental study of fire containment using water mist curtains in a reduced-scale deck of a ro-ro ship

Experiments have been conducted to evaluate the containment of smoke and heat using water mist curtains in a model setup of a ro-ro ship's cargo deck with a scale of 1:13, providing practical insights into the application of such fire protection systems in the cargo deck as well as valuable data for future numerical simulations. In this regard, the requirements of the international convention of Safety of Life at Sea (SOLAS) are studied for the side openings of so-called ‘open decks’ in comparison with ‘closed decks’, especially to examine the feasibility of using water mist curtains for creating isolated subdivisions in the ro-ro space as a fire management strategy. The water mist curtains are created with one or two rows of water mist nozzles at pressures ranging from 3 to 8 bar, while the source of smoke and heat is a liquid pool fire, and inert cargo items are used in some experiments. Correspondingly, the interaction between the water mist curtain(s) and the fire is evaluated in terms of its heat release rate, and the containment effect is quantified via measurements of smoke flow through the deck and through the windows, concentrations of gaseous species, as well as gas temperatures at various key locations. The study shows that water mist curtains have a strong effect on fire dynamics and smoke propagation, but containment is dependent on the configuration of side openings and the location of fire, among other important factors

Manipulating Eryptosis of Human Red Blood Cells: A Novel Antimalarial Strategy?

Malaria is a major global health burden, affecting over 200 million people worldwide. Resistance against all currently available antimalarial drugs is a growing threat, and represents a major and long-standing obstacle to malaria eradication. Like many intracellular pathogens, Plasmodium parasites manipulate host cell signaling pathways, in particular programmed cell death pathways. Interference with apoptotic pathways by malaria parasites is documented in the mosquito and human liver stages of infection, but little is known about this phenomenon in the erythrocytic stages. Although mature erythrocytes have lost all organelles, they display a form of programmed cell death termed eryptosis. Numerous features of eryptosis resemble those of nucleated cell apoptosis, including surface exposure of phosphatidylserine, cell shrinkage and membrane ruffling. Upon invasion, Plasmodium parasites induce significant stress to the host erythrocyte, while delaying the onset of eryptosis. Many eryptotic inducers appear to have a beneficial effect on the course of malaria infection in murine models, but major gaps remain in our understanding of the underlying molecular mechanisms. All currently available antimalarial drugs have parasite-encoded targets, which facilitates the emergence of resistance through selection of mutations that prevent drug-target binding. Identifying host cell factors that play a key role in parasite survival will provide new perspectives for host-directed anti-malarial chemotherapy. This review focuses on the interrelationship between Plasmodium falciparum and the eryptosis of its host erythrocyte. We summarize the current knowledge in this area, highlight the different schools of thoughts and existing gaps in knowledge, and discuss future perspectives for host-directed therapies in the context of antimalarial drug discovery