Impact of nonlocal interactions in dissipative systems: towards minimal-sized localized structures

In order to investigate the size limit on spatial localized structures in a nonlinear system, we explore the impact of linear nonlocality on their domains of existence and stability. Our system of choice is an optical microresonator containing an additional metamaterial layer in the cavity, allowing the nonlocal response of the material to become the dominating spatial process. In that case, our bifurcation analysis shows that this nonlocality imposes a new limit on the width of localized structures going beyond the traditional diffraction limit.Comment: 4 pages, 4 figure

<i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration

We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac

Lésions de la « maladie du carré » chez le porc

Billon Jean, Tassin P. Lésions de la «Maladie du carré» chez le porc. In: Bulletin de l'Académie Vétérinaire de France tome 128 n°8, 1975. pp. 389-394

Revealing the true partitioning character of zirconium in additively manufactured polycrystalline superalloys

International audienc

Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials

We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing a mean-field model, we show that the sign of diffraction can be made either positive or negative in this resonator, depending on the thicknesses of the layers. Subsequently, we demonstrate that the dynamical behavior of the modulation instability is strongly affected by the sign of the diffraction coefficient. Finally, we study the dissipative structures in this resonator and reveal the predominance of a two-dimensional up-switching process over the formation of spatially periodic structures, leading to the truncation of the homogeneous hysteresis cycle.Comment: 8 pages, 5 figure

Microstructural evolution of a low-alloy steel / nickel superalloy dissimilar metal weld during post-weld heat treatment

The microstructural evolution of a dissimilar metal weld (DMW) obtained by narrow-gap gas tungsten arc welding (NG-GTAW) was investigated after it was subjected to a post-weld heat treatment (PWHT). The case studied here is a joint between low-alloy steel pipes and a stainless steel steam generator using a nickel based alloy as filler material. The fusion boundary that was the focus of this work was that between the low-alloy steel (2.25Cr-1Mo) and the nickel alloy (alloy 82). The difference in matrix phase and chemical composition between the two alloys leads to a large difference in chemical potential for carbon, which is mobile at the PWHT temperature. A number of advanced characterization techniques were used to assess the gradient of composition, hardness and microstructures across the fusion line, both as welded and after PWHT. This complete analysis permits to highlight and understand the main microstructural changes occurring during the PWHT

Tunable hybrid surface waves supported by a graphene layer

We study surface waves localized near a surface of a semi-infinite dielectric medium covered by a layer of graphene in the presence of a strong external magnetic field. We demonstrate that both TE-TM hybrid surface plasmons can propagate along the graphene surface. We analyze the effect of the Hall conductivity on the disper- sion of hybrid surface waves and suggest a possibility to tune the plasmon dispersion by the magnetic field.Comment: 3 pages, 3 figure

Produção de Brachiaria brizantha cv. Marandu quando consorciada com Sorghum bicolor sob períodos de estresse hídrico.

Verificar o desenvolvimento da Brachiaria brizantha cv. Marandu quando em cultivo consorciado com o sorgo, submetida a períodos de déficit hídrico