Vectorial dissipative solitons in vertical-cavity surface-emitting Lasers with delays

We show that the nonlinear polarization dynamics of a vertical-cavity surface-emitting laser placed into an external cavity leads to the formation of temporal vectorial dissipative solitons. These solitons arise as cycles in the polarization orientation, leaving the total intensity constant. When the cavity round-trip is much longer than their duration, several independent solitons as well as bound states (molecules) may be hosted in the cavity. All these solutions coexist together and with the background solution, i.e. the solution with zero soliton. The theoretical proof of localization is given by the analysis of the Floquet exponents. Finally, we reduce the dynamics to a single delayed equation for the polarization orientation allowing interpreting the vectorial solitons as polarization kinks.Comment: quasi final resubmission version, 12 pages, 9 figure

CRY2 Is Associated with Rapid Cycling in Bipolar Disorder Patients

Bipolar disorder patients often display abnormalities in circadian rhythm, and they are sensitive to irregular diurnal rhythms. CRY2 participates in the core clock that generates circadian rhythms. CRY2 mRNA expression in blood mononuclear cells was recently shown to display a marked diurnal variation and to respond to total sleep deprivation in healthy human volunteers. It was also shown that bipolar patients in a depressive state had lower CRY2 mRNA levels, nonresponsive to total sleep deprivation, compared to healthy controls, and that CRY2 gene variation was associated with winter depression in both Swedish and Finnish cohorts.Four CRY2 SNPs spanning from intron 2 to downstream 3'UTR were analyzed for association to bipolar disorder type 1 (n = 497), bipolar disorder type 2 (n = 60) and bipolar disorder with the feature rapid cycling (n = 155) versus blood donors (n = 1044) in Sweden. Also, the rapid cycling cases were compared with bipolar disorder cases without rapid cycling (n = 422). The haplotype GGAC was underrepresented among rapid cycling cases versus controls and versus bipolar disorder cases without rapid cycling (OR = 0.7, P = 0.006-0.02), whereas overrepresentation among rapid cycling cases was seen for AAAC (OR = 1.3-1.4, P = 0.03-0.04) and AGGA (OR = 1.5, P = 0.05). The risk and protective CRY2 haplotypes and their effect sizes were similar to those recently suggested to be associated with winter depression in Swedes.We propose that the circadian gene CRY2 is associated with rapid cycling in bipolar disorder. This is the first time a clock gene is implicated in rapid cycling, and one of few findings showing a molecular discrimination between rapid cycling and other forms of bipolar disorder

Investigation of physico-chemical features of soil colloidal suspensions.

The knowledge of surface properties of soil mobile colloids is of great importance to predict their role, but these properties are difficult to assess due to the heterogeneity and the complex nature of natural colloids. Physico-chemical features of natural colloids circulating in the soil solution were investigated with complementary approaches: microscopic techniques (TEM and AFM), potentiometric titrations and electrophoretic measurements. This study was realized on two colloidal suspensions isolated from soil solutions collected in situ from the plough layers of two different soils (MC and MPM). Colloidal particle properties including morphology, size distribution, specific surface area, electrophoretic mobility, and surface site concentration were compared before and after oxidation of the organic matter of the colloidal suspensions by H2O2 treatment. Statistical analysis of the geometrical features of TEM and AFM images revealed a comparable mean size of 170 70 nut for the two samples, and a mean height of 6.5 +/- 4.6 mn and 9.9 +/- 8.2 nm for the MPM and MC, respectively. From the 3D-analysis of AFM images, the specific surface areas were assessed at 203 m(2)/g and 260 m(2)/g for MC and MPM suspensions, respectively. Phyllosilicates (illite, interstratified clays and smectite) primarily present in the two samples seem to dominate the surface charge behaviour of the soil colloidal suspensions as seen by potentiometric or electrophoretic titrations. However, TEM after staining and AFM observations show also the presence of organic phases with different status according to the sample, i.e. surface coatings or interparticle bonds. The data clearly indicate the influence of organic matter on the main physico-chemical characteristics of colloids (morphology, size distribution and surface charge) related to the reactivity and the transfer of colloids in soils. (c) 2006 Elsevier B.V. All rights reserved