Towed sensors and hydrodynamic model evidence the need to include submarine in coastal lagoons water balance, the Mar Menor example (SE Spain).

The use of radionuclide tracers to determine the submarine groundwater discharges has been used widely but in areas highly anthropized as the Mar Menor surface water tributaries can carry high concentration of Radon, making very difficult to distinguish the radionuclide origin. In this paper a combined approach was applied in the Mar Menor, a towed system was designed to enable the continuous measurement of Radon and Nitrate and a hydrodynamic model was used to establish the influence areas of the surface discharge to the lagoon. The areas were Radon was detected and was out from the area located with the model could be establish as a submarine groundwater discharge point.Peer Reviewe

Effect of the intermediate velocity emissions on the quasi-projectile properties for the Ar+Ni system at 95 A.MeV

The quasi-projectile (QP) properties are investigated in the Ar+Ni collisions at 95 A.MeV taking into account the intermediate velocity emission. Indeed, in this reaction, between 52 and 95 A.MeV bombarding energies, the number of particles emitted in the intermediate velocity region is related to the overlap volume between projectile and target. Mean transverse energies of these particles are found particularly high. In this context, the mass of the QP decreases linearly with the impact parameter from peripheral to central collisions whereas its excitation energy increases up to 8 A.MeV. These results are compared to previous analyses assuming a pure binary scenario

Response of CsI(Tl) scintillators over a large range in energy and atomic number of ions (Part I): recombination and delta -- electrons

A simple formalism describing the light response of CsI(Tl) to heavy ions, which quantifies the luminescence and the quenching in terms of the competition between radiative transitions following the carrier trapping at the Tl activator sites and the electron-hole recombination, is proposed. The effect of the delta rays on the scintillation efficiency is for the first time quantitatively included in a fully consistent way. The light output expression depends on four parameters determined by a procedure of global fit to experimental data.Comment: 28 pages, 6 figures, submitted to Nucl. Inst. Meth.

Microtubule length dependence of motor traffic in cells

In living cells, motor proteins, such as kinesin and dynein can move processively along microtubule (MT), and also detach from or attach to MT stochastically. Experiments have found that, the traffic of motor might be jammed, and various theoretical models have been designed to understand this traffic jam phenomenon. But previous studies mainly focus on motor attachment/detachment rate dependent properties. Recent experiment of Leduc {\it et al.} found that the traffic jam formation of motor protein kinesin depends also on the length of MT [Proc. Natl. Acad. Sci. U.S.A. {\bf 109}, 6100-6105 (2012)]. In this study, the MT length dependent properties of motor traffic will be analyzed. We found that MT length has one {\it critical value} $N_c$, traffic jam occurs only when MT length $N>N_c$. The jammed length of MT increases with total MT length, while the non-jammed MT length might not change monotonically with the total MT length. The critical value $N_c$ increases with motor detachment rate from MT, but decreases with motor attachment rate to MT

Ultrasonic guided waves on a periodical grating : coupled modes in the first Brillouin zone

The propagation of Lamb waves in a plate with an engraved periodic grating is addressed in this article. Mode conversions and reflections are analyzed. In the first part the conversion modes are explained by the existence of a resonance condition between the Lamb-wave wavenumbers and the fundamental and harmonic spatial periods of the grating. These phenomena are experimentally and numerically highlighted for a metallic waveguide with a rectangular grating. The second part focuses on the pseudo-Lamb wave dispersion curves in a periodic waveguide. The periodicity implies that the Lamb waves dispersion curves fold back at the edge of the Brillouin zone. Several stop bands appear: classical band gaps at the boundary of the Brillouin zone and mini-stop-bands inside the Brillouin zone. For the ministop band, dispersion curves cross and a possible coupling occurs between the modes. Finally, conversions or the existence of gaps are linked with the Power Spectral Density of the grating profile

L’activité volcanique du Stromboli : un laboratoire naturel de choix à la base de la classification des projections

International audienc

L’activité volcanique du Stromboli : un laboratoire naturel de choix à la base de la classification des projections

International audienceTextural and chemical analyses of bombs quenched directly from a strombolian explosion were integrated with coincident seismic, acoustic and thermal data, for Stromboli volcano. The data set defines a new gas-dominated type of “strombolian” eruption (Type 0). Type 0 events are characterized by high velocity emission (150-250 m s-1) of a few, relatively small, juvenile particles, with entrained lithics that have fallen back into the vent to be re-erupted. For the studied event, the explosion depth was more than 250 m deep, and the particles showed little residence (degassing) time in the shallow system between the surface and the free magma surface. Slug ascent velocities over the final 20-35 m of magma-filled conduit, and the low viscosity of the resident magma, are all consistent with simple bubble burst in a “clean” conduit. This conduit type and eruption style likely fits popular slug ascent and burst models used to explain “strombolian” eruptions. Our comparison with a Type 1 (ballistic-dominated) eruption shows that such events are associated with larger proportions of degassed material in the shallow system magma mix. We argue that the additional volume of this degassed material pushes the free surface upwards. Because of the larger volume of material available for entrainment into a Type 1 slug burst, which has to fragment through a thick cap of degassed material, Type 1 events tend to be rich in particles. In contrast, the less spectacular, gas-rich (Type 0) events have little material to entrain, thus being poor in lapilli and bombs. Our results also show the importance of sampling the bombs, as well as scoria and ash, during Strombolian events, in parallel with key geophysical and remote sensing measurements. Such a truly multidisciplinary sampling strategy, integrated by textural and geochemical studies, is essential if we are to properly understand, model, and explain the dynamics and mechanisms of Strombolian eruptions, as well as to correctly apply models and assumptions to extract shallow system dynamics from geophysical data sets.Les analyses chimiques et texturales de bombes trempées provenant directement de l’explosion strombolienne sont intégrées avec des données sismiques, acoustiques et thermiques acquises simultanément sur le volcan Stromboli. Ce groupe de données défini un nouveau « type d’éruption strombolienne », le type 0. Les évènements de type 0 sont caractérisés par des vitesses d’émission élevées (150-250 m.s.-1) de quelques petites, particules juvéniles, et entrainent des particules lithiques qui étaient retombées dans l’évent pour être remobilisée lors de l’éruption suivante. Pour l’évènement étudié, l’explosion était à plus de 250 m de profondeur et les particules montraient un temps de résidence courts (peu de dégazage) dans le système volcanique superficiel entre la surface et la surface du magma. Les larges bulles de gaz éclatant au niveau de la surface de la colonne magmatique (un slug) ont des vitesses d’ascension, sur les 20 à 35 derniers mètres du conduit rempli de magma de faible viscosité, qui sont en accord avec un phénomène de simple éclatement de bulles dans un conduit « propre ». Ce type de conduit et d’éruption est utilisé dans les modélisations des éruptions dites “stromboliennes”. Une comparaison avec une éruption de type 1 (dominée par des balistiques) montre que ces évènements sont associés à des proportions plus grandes de matériel dégazés dans le système magmatique plus superficiel. Les éruptions de type 1 ont tendance à avoir plus de particules car elles doivent traverser et fracturer une croûte épaisse de matériel dégazé qui couvre la surface du magma. Au contraire les évènements de type 0 qui sont moins spectaculaires, sont plus riches en gaz, entrainent peu de matériel et sont donc pauvres en lapilli et bombes. Nos résultats montrent l’importance d’échantillonner les bombes ainsi que les scories et les cendres pendant un évènement strombolien, d’associer les analyses texturales et géochimiques, ainsi que l’importance d’acquérir simultanément des données géophysiques clés et des mesures de télédétection