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Lieux et pratiques de la plongée sous-marine sur la côte marseillaise : pour une approche géographique intégrée de l’espace marin littoral
No full textInternational audienceBeing a growing recreational activity on many coasts in the world, scuba diving is mainly known thanks to studies conducted in the frame of marine protected areas (MPAs). For management purposes indeed, it is necessary to know scuba diving practices and their ecological impact. But it is also important to report the socio-economic added value of this activity and thus the social utility of the environmental protection measures. Yet, as for many other recreational activities at sea, knowledge about scuba diving remain relatively incomplete and often unreliable. Furthermore, in the case of complex coastal zones, the geographical extent of the practices does not match systematically with the area of an MPA when it exists. It is therefore relevant to approach this activity at the level of the territorial system in which it occurs. This is the subject of this article which deals with the coast of Marseille (France), one of the world’s cradles of diving. Combining a large commercial port with various marine protected areas with distinct regulations, this coast is a prime but complex area for this activity. From a survey of key diving structures, a descriptive geography of scuba diving can then be revealed. It is then discussed with the management areas and the few efforts to organize the activity on the whole coast, from the integrated coastal area management perspective.Activité récréative en pleine croissance sur de nombreux littoraux du monde, la plongée sous-marine est principalement connue grâce à des études conduites dans le cadre d’aires marines protégées (AMP). Les préoccupations de gestion imposent en effet de connaître les pratiques et leurs effets sur les milieux, mais aussi les retombées socio-économiques de l’activité et ainsi l’utilité sociale de la protection de l’environnement. Pourtant, comme pour de nombreuses autres activités récréatives en mer, les connaissances sur la plongée demeurent relativement lacunaires et sont souvent sujettes à caution. En outre, dans le cas de zones côtières complexes, l’espace des pratiques ne se confond pas systématiquement avec le périmètre d’une AMP lorsqu’elle existe. Il est alors pertinent d’appréhender cette activité au niveau du système territorial dans lequel elle s’insère. Tel est le propos de cet article qui s’intéresse au littoral de Marseille (France), l’un des berceaux mondiaux de la plongée. Juxtaposant un grand port de commerce avec divers périmètres de protection de l’espace marin littoral aux réglementations distinctes, ce littoral constitue une zone privilégiée pour cette activité. À partir d’une enquête auprès des principales structures d’encadrement de la plongée, une géographie des pratiques est alors révélée. Dans une perspective de démarche intégrée, elle est ensuite mise en discussion avec les périmètres de gestion et les quelques efforts d’organisation de l’activité sur l’ensemble du littoral
Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals
No full textInternational audienceWe present the neodymium isotopic composition (εNd) of mixed planktonic foraminifera species from a sediment core collected at 622 m water depth in the Balearic Sea, as well as εNd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442 m water depth in the Alboran Sea and at 414 m depth in the South Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (δ 18O) and carbon (δ 13 C) isotopes. The foraminiferal and coral εNd values from the Balearic and Alboran Sea are comparable over the last ~13 kyr, with mean values of -8.94±0.26 (1σ; n=24) and - 8.91±0.18 (1σ; n=25), respectively. Before 13 ka BP, the foraminiferal εNd values are slightly lower (- 9.28±0.15) and tend to reflect higher mixing between intermediate and deep waters, which are characterized by more unradiogenic εNd values. The slight εNd increase after 13 ka BP is associated to a decoupling in the benthic foraminiferal δ 13C composition between intermediate and deeper depths, which started at ~16 ka BP. This suggests an earlier stratification of the water masses and a subsequent reduced contribution of unradiogenic εNd from deep waters. The CWC from the Sardinia Channel show a much larger scatter of εNd values, from - 8.66±0.30 to -5.99±0.50, and a lower average (-7.31±0.73; n=19) compared to the CWC and foraminifera from the Alboran and Balearic Sea, indicative of intermediate waters sourced from the Levantine basin. At the time of sapropel S1 deposition (10.2 to 6.4 ka), the εNd values of the Sardinian CWC become more unradiogenic (- 8.38±0.47; n=3 at ~8.7 ka BP), suggesting a significant contribution of intermediate waters originated from the western basin. We propose that western Mediterranean intermediate waters replaced the Levantine Intermediate Water (LIW), and thus a strong reduction of the LIW during the mid-sapropel (~8.7 ka BP). This observation supports a notable change of Mediterranean circulation pattern centered on sapropel S1 that needs further investigations to be confirmed
Serious games to teach social interactions and emotions to individuals with autism spectrum disorders (ASD)
No full textInternational audienceThe use of information communication technologies (ICTs) in therapy offers new perspectives for treating many domains in individuals with autism spectrum disorders (ASD) because they can be used in many different ways and settings and they are attractive to the patients. We reviewed the available literature on serious games that are used to teach social interactions to individuals with ASD. After screening the Medline, Science Direct and ACM Digital Library databases, we found a total of 31 serious games: 16 that targeted emotion recognition or production and 15 that targeted social skills. There was a significant correlation between the number of reports per year and the year of publication. Serious games appeared promising because they can support training on many different skills and they favour interactions in diverse contexts and situations, some of which may resemble real life. However, the currently available serious games exhibit some limitations: (i) most of them are developed for High-Functioning individuals; (ii) their clinical validation has rarely met the evidence-based medicine standards; (iii) the game design is not usually described; and, (iv) in many cases, the clinical validation and playability/game design are not compatible
Dependence of near field co-seismic ionospheric perturbations on surface deformations: A case study based on the April, 25 2015 Gorkha Nepal earthquake
No full textInternational audienceIonospheric response to the recent 25 April 2015 Gorkha, Nepal earthquake is studied in terms of Global Positioning System-Total Electron Content (GPS-TEC) from the viewpoints of source directivity, rupture propagation and associated surface deformations, over and near the fault plane. The azimuthal directivity of co-seismic ionospheric perturbations (CIP) amplitudes from near field exhibit excellent correlation with east-southeast propagation of earthquake rupture and associated surface deformations. In addition, the amplitude of CIP is observed to be very small in the opposite direction of the rupture movement. Conceptual explanations on the poleward directivity of CIP exist in literature, we show the observational evidences of additional equator ward directivity, interpreted in terms of rupture propagation direction. We also discuss the coupling between earthquake induced acoustic waves and local geomagnetic field and its effects on near field CIP amplitudes. We suggest that variability of near field CIP over and near the fault plane are the manifestations of the geomagnetic field-wave coupling in addition to crustal deformations that observed through GPS measurements and corroborated by Interferometric Synthetic Aperture Radar (InSAR) data sets
Some key physical ingredients in dense suspension simulations
No full textInternational audienceThis numerical work intends to highlight the most prominent physical ingredients needed for reliable simulations of dense suspensions. We especially address the role of friction, roughness, and long-range hydrodynamics. Simulations show that friction between particles significantly alters viscosity and normal stresses and leads to an improved correlation with available experiments. A new finding is that friction also increases particle diffusion by a factor of two and provides better agreement on the irreversibility threshold in Pine's experiments. Particle roughness is numerically shown to alter rheology only slightly : a large roughness leads to a small decrease in the viscosity since lubrication dissipation is lowered. Frictional roughness seems to minimize this even more and, by and large, roughness size has only limited effects on rheology. However, large roughness and confinement can trigger the onset of particle layering which strongly decreases diffusion. Finally, we have evaluated the effect of long-range hydrodynamics in dense suspensions. To this end, we have compared full Stokes simulations with widely used molecular dynamics simulations. Our first results on frictionless particles show that there is a slight difference on viscosity although it still diverges similarly (same φ* ≈ 0.64 and similar critical exponent) whether long-range interactions are accounted or not. Frictional simulations are on the way to confirm this behavior
Inhibition of effector antigen-specific T cells by intradermal administration of heme oxygenase-1 inducers
No full textInternational audienceDeveloping protocols aimed at inhibiting effector T cells would be key for the treatment of T cell-dependent autoimmune diseases including type 1 autoimmune diabetes (T1D) and multiple sclerosis (MS). While heme oxygenase-1 (HO-1) inducers are clinically approved drugs for non-immune-related diseases, they do have immunosuppressive properties when administered systemically in rodents. Here we show that HO-1 inducers inhibit antigen-specific effector T cells when injected intradermally together with the T cell cognate antigens in mice. This phenomenon was observed in both a CD8 þ T cell-mediated model of T1D and in a CD4 þ T cell-dependent MS model. Intradermal injection of HO-1 in-ducers induced the recruitment of HO-1 þ monocyte-derived dendritic cell (MoDCs) exclusively to the lymph nodes (LN) draining the site of intradermal injection. After encountering HO-1 þ MoDCs, effector T-cells exhibited a lower velocity and a reduced ability to migrate towards chemokine gradients resulting in impaired accumulation to the inflamed organ. Intradermal co-injection of a clinically approved HO-1 inducer and a specific antigen to non-human primates also induced HO-1 þ MoDCs to accumulate in dermal draining LN and to suppress delayed-type hypersensitivity. Therefore, in both mice and non-human primates, HO-1 inducers delivered locally inhibited effector T-cells in an antigen-specific manner, paving the way for repositioning these drugs for the treatment of immune-mediated diseases
Développements d’un code de laboratoire multi-physique basé sur la méthode TLM
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