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

Duplication of the great saphenous vein: A definition problem and implications for therapy

BACKGROUND: In the literature there is a range from 1% to 20% of duplication (up to 20%) of the great saphenous vein (GSV) reported, because there is a lack of an accurate definition of the GSV and objective parameters for an anatomical identification. OBJECTIVE: To investigate the frequency of true duplications of the GSV. MATERIALS AND METHODS: A systematic review of the literature, a retrospective analysis of duplex examinations, and a prospective study of duplex examinations to investigate the frequency of true duplications of the GSV. RESULTS: In the literature review, a great variety of definitions is used for duplication of the GSV. Before the consensus of the Union International de Phlébologie (UIP) in 2006, Only in a small number of studies, the definition of the GSV in the saphenous compartment between the fascial blades is mentioned. CONCLUSION: Phlebographic studies have been the criterion standard for the identification of venous anatomy. Now, duplex is regarded as the criterion standard for accurate detection of the veins. True duplication of the GSV is less common than the previous literature has suggested, namely 1.6% to 2%. It is recommended that the duplicated GSV should be treated to avoid an important risk of recurrence of venous insufficiency

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

Lower-extremity venous insufficiency is a common condition, associated with considerable health care costs. Endovenous laser ablation is increasingly used as therapy, but its mechanism of action is insufficiently understood. Here, direct absorption of the laser light, collapsing steam bubbles and direct fiber-wall contact have all been mentioned as contributing mechanisms. Because fiber tips have reported temperatures of 800-1,300°C during endovenous laser ablation, we sought to assess whether heat conduction from the hot tip could cause irreversible thermal injury to the venous wall. We approximated the hot fiber tip as a sphere with diameter equal to the fiber diameter, having a steady state temperature of 800°C or 1,000°C. We computed venous wall temperatures due to heat conduction from this hot sphere, varying the pullback velocity of the fiber and the diameter of the vein. Venous wall temperatures corresponding to irreversible injury resulted for a 3 mm diameter vein and pullback velocities <3 mm/s but not for 5 mm and 1 mm/s. The highest wall temperature corresponded to the position on the wall closest to the fiber tip, hence it moves longitudinally in parallel with the moving fiber tip. We concluded that heat conduction from the hot fiber tip is a contributing mechanism in endovenous laser ablation

Dialogue avec l'oeuvre ravagee

Au terme de carrieres consacrees a l'examen et a la restauration des chefs-d'oeuvre du patrimoine national deux specialistes un historien de l'art et un microchimiste se sont penches sur les problemes de la conservation une matiere combien complexe inepuisable et controversee depuis bientot trois siecles. Leur ouvrage n'est ni un atlas de la pathologie des tableaux et des sculptures ni un livre de recettes ni un manuel qui explique en detail les etapes d'un certain nombre d'interventions visant a restaurer les oeuvres. Il propose une reflexion sur le fond du probleme a la lumiere de la pratique de l'atelier de restauration et celle des acquis de laboratoire. Et ce en dehors des clans et des ecoles loin des connivences. Les auteurs essaient d'evaluer le sens et le non-sens des interventions qu'on estime pouvoir imposer aux oeuvres. Ils invitent a ecouter l'oeuvre. Et de quoi nous parlent les images ravagees? Des oeuvres intactes de la beaute de l'ephemere sans oublier le comportement etonnant des hommes envers ce qu'ils ont cree de meilleur

Nonlinear dispersive similariton in passive fibers

International audienc

Nonlinear-dispersive similariton of passive fiber

Using the spectral-interferometry method for the short pulse complete characterization, we demonstrate the nature and distinctive properties of the similariton generated in single-mode fiber without gain (passive fiber) due to the combined impacts of nonlinearity and dispersion. The nonlinear-spectronic character of such a similariton, with the key specificity of linear chirping, leads to its self-spectrotemporal imaging, important for applications to the signal analysis - synthesis problems in ultrafast optics.SCOPUS: ar.jinfo:eu-repo/semantics/publishe