Search

International audience; Infectious bursal disease (IBD) is an immunosuppressive viral disease, present worldwide, which causes mortality and immunosuppression in young chickens. The causative agent, the Avibirnavirus IBDV, is a non-enveloped virus whose genome consists of two segments (A and B) of double-stranded RNA. Different pathotypes of IBDV exist, ranging from attenuated vaccine strains to very virulent viruses (vvIBDV). In Algeria, despite the prophylactic measures implemented, cases of IBD are still often diagnosed clinically and the current molecular epidemiology of IBDV remains unknown. The presence of the virus and especially of strains genetically close to vvIBDV was confirmed in 2000 by an unpublished OIE report. In this study, nineteen IBDV isolates were collected in Algeria between September 2014 and September 2015 during clinical outbreaks. These isolates were analyzed at the genetic, antigenic and pathogenic levels. Our results reveal a broad genetic and phenotypic diversity of pathogenic IBDV strains in Algeria, with, i) the circulation of viruses with both genome segments related to European vvIBDV, which proved as pathogenic for specific pathogen-free chickens as vvIBDV reference strain, ii) the circulation of viruses closely related - yet with a specific segment B - to European vvIBDV, their pathogenicity being lower than reference vvIBDV, iii) the detection of reassortant viruses whose segment A was related to vvIBDV whereas their segment B did not appear closely related to any reference sequence. Interestingly, the pathogenicity of these potentially reassortant strains was comparable to that of reference vvIBDV. All strains characterized in this study exhibited an antigenicity similar to the cognate reference IBDV strains. These data reveal the continuous genetic evolution of IBDV strains in Algerian poultry through reassortment and acquisition of genetic material of unidentified origin. Continuous surveillance of the situation as well as good vaccination practice associated with appropriate biosecurity measures are necessary for disease control.

Fire is considered the major disturbance in boreal forests. Nonetheless, in several areas logging has become the primary driver of forest dynamics. In many areas of the boreal forest, stands may undergo paludification (i.e. the accumulation of thick, poorly decomposed organic layers over the mineral soil) in the prolonged absence of fire, which reduces forest productivity. Whereas high-severity fires (HSF) may restore forest productivity by burning the soil organic layer (SOL), low-severity fires (LSF) mainly burn the soil surface and do not significantly reduce SOL thickness. In the Clay Belt region of eastern Canada, an area prone to paludification, forest stands have historically been harvested by clearcutting (CC), but concerns about the protection of soils and tree regeneration lead to the replacement of CC by careful logging (CL). Whereas CC disturbs the SOL and is thought to favor tree growth, CL has little impact on the SOL. Furthermore, it has been suggested that prescribed burning after clearcut (CCPB) could also be used to control paludification. Using a retrospective approach, this study sought to understand how CC, CL, and CCPB compare to LSF and HSF with respect to soil properties, SOL thickness, vegetation ground cover, tree nutrition, and stand height in paludified black spruce stands of the Clay Belt region. HSF led to significantly taller trees than CL and LSF, but did not differ from CC and CCPB. Foliar N was significantly higher in HSF and CCPB sites relative to CL and LSF, with an intermediate value in CC sites. Ground cover of Rhododendron groenlandicum was significantly lower in HSF and CC sites relative to LSF, with intermediate values in CL and CCPB sites. Sphagnum spp. ground cover was significantly lower in HSF and CCPB sites relative to CL, with intermediate values in CC and LSF sites. High-severity fire sites had a significantly thinner SOL than the four other disturbances. Finally, regression tree analysis showed that SOL thickness represented the best predictor of tree height, whereas segmented regression showed that tree height was negatively correlated to SOL thickness and revealed a cut-off point circa 23 cm, which suggests that tree growth is impeded beyond this threshold. These results support the idea that management strategies intending to regenerate paludified forests should primarily aim at reducing organic layer thickness, either through mechanical disturbance or combustion.

Paludification, the accumulation over the mineral soil of poorly decomposed organic matter mainly originating from Sphagnum spp., transforms black spruce ( Picea mariana ) boreal forests into forested peatlands in the prolonged absence of fire, which diminishes forest productivity. High-severity wildfires reset this process by burning the soil organic layer (SOL) and reinitiating forest succession. In contrast, low severity wildfires impact mainly the soil surface and tree layer and do not significantly reduce SOL depth. In the Clay Belt region of eastern Canada, an area prone to paludification, the current forest harvest practice (careful logging around advanced growth [CLAAG]) removes trees but has little impact on the SOL and the understorey vegetation. This is thought to further promote paludification, which consequently reduces forest productivity. Conversely, clearcut (CC) disturbs the SOL and the understorey vegetation, and is thought to favor tree growth. Furthermore, prescribed burning after clearcut (CCPB) is used as a site preparation technique, but may also be used to control paludification as it can burn part of the organic soil layer. Using a retrospective approach, our study examines three hypotheses: compared to CLAAG, CC and CCPB: (1) have positive effects on soil conditions (e.g. decomposition level and pH), (2) reduce Sphagnum spp. and ericaceous shrub cover and (3) result in enhanced black spruce growth. We sampled 22 sites in which we measured SOL characteristics (e.g. depth, decomposition state), understorey vegetation cover and black spruce growth. Compared to CLAAG, CCPB resulted in increased soil decomposition level and higher pH. CCPB also reduced Sphagnum spp. cover but not ericaceous shrub cover. Black spruce growth rate was higher following CCPB than CC, and mean dominant tree height was marginally higher following CCPB than CLAAG and CC. Our results demonstrate that CCPB is beneficial to black spruce growth, presumably through its effects on forest understorey and SOL chemistry. While not similar to a high severity fire, prescribed burning after clearcut in paludified stands on the Clay Belt emulates some wildfire effects such as increasing soil pH. We suggest that unlike CLAAG, prescribed burning after clearcut can restore black spruce stand productivity and should be considered in the context of forest ecosystem management.

The mixed ligand complexes [{Gd(OCMe2-i-Pr)2Cp}2], [{Sm(OCMe2-i-Pr)2Cp}2], and [Sm2(OCMe2-i-Pr)3Cp3] were synthesized by reacting [LnCp3] with HOCMe2-i-Pr. X-ray crystallographic studies show that the three complexes each have two bridging alkoxide ligands linking two metal atoms. The coordination geometries at the metals are distorted tetrahedral.

Reaction of CeCl3 with an excess of LiTMP (TMP-H = 2,2,6,6-tetramethylpiperidine) gave [Ce(μ-OCH CH2)(TMP)2]2. The alkoxide ligand originated from THF, which was used as the solvent in the reaction. CeCl3 reacted with 3 equiv. of LiTMP in THF to produce, after crystallization, a 3:2 crystalline mixture of Ce(TMP)3 and [Ce(μ-OCH CH2)(TMP)2]2. Ce(TMP)3 could not be isolated cleanly or separated from the mixture except by handpicking the crystals under a microscope. The homoleptic amide complex Ce[N-t-Bu(SiMe3)]3 was obtained by reacting CeCl3(THF)2 with 3 equivalents of LiN-t-Bu(SiMe3). In the solid state, [Ce(μ-OCH CH2)(TMP)2]2 is a dimer with a Ce(μ-OR)2Ce four-member ring, while Ce(TMP)3 and Ce[N-t-Bu(SiMe3)]3 are trigonal planar monomers. There is structural evidence to suggest the presence of a Ce–vinyl group interaction in [Ce(μ-OCH CH2)(TMP)2]2.

Chlorotris(trimethylhydrazido)titanium, TiCl(NMeNMe2)3, was synthesized by reacting TiCl2(NMeNMe2)2 with 1 equiv. of LiNMeNMe2. Tetrakis(trimethylhydrazido)zirconium and hafnium, M(NMeNMe2)4, were prepared from MCl4 and 4 equiv. of LiNMeNMe2 but Ti(NMeNMe2)4 could not be prepared cleanly from TiCl4. Instead, it was synthesized from TiCl(NMeNMe2)3 and LiNMeNMe2. X-ray crystallographic studies show that TiCl(NMeNMe2)3 and Ti(NMeNMe2)4 have three bidendate hydrazide ligands and Zr(NMeNMe2)4 has four bidendate ligands.

This article discusses conflicts of interest existing between investors and their financial advisors. Several contributions in this field treated this question in relation either with invested amount or with expected holding period of the mutual fund. Our paper considers an approach globalizing these two parameters. The first part describes the organization of mutual fund fees in the US. Thanks to a numerical simulation, the second part emphasizes the conflict of interest focusing on the expected holding period. The third one analyses the changes of variables and their consequences on characteristics of investors concerned by this conflict of interest., Cet article traite des conflits d'intérêts existant entre les investisseurs et leur conseiller financier. Des contributions antérieures ont apporté des éclairages sur cette question en considérant soit les montants investis soit l'horizon d'investissement des investisseurs. Cet article intègre ces différentes dimensions dans une approche globale. La première partie décrit le système des frais aux Etats-Unis. La seconde, grâce à une simulation numérique, met en évidence le conflit d'intérêt en se concentrant uniquement sur l'horizon d'investissement. La troisième partie traite des changements de variables et leurs conséquences sur les caractéristiques des investisseurs concernés par ce conflit d'intérêts.

s / Can J Diabetes 38 (2014) 151e153 153 exposed to HG in normoxia (P1⁄40.0204 for PDGF) and in hypoxia. We observed that HG inhibited PDGF-induced vSMC migration, an effect that was amplifiedwhen exposed to hypoxia. Intriguingly, we did not observed any change in insulinor PDGF-stimulated Akt or ERK activation in cells treated with HG and/or hypoxia. In conclusion, hyperglycemia affects vSMC proliferation and migration in hypoxic condition. However, more experiments are needed to determine the mechanisms involved in this phenomenon. Funding: This work was supported by the Canadian association of diabetes (CDA) operating grant (P.G.). P.G is a recipient of a Canada Research Chair in Diabetes and Vascular Complications and Canadian Diabetes Association Scholar Award. M.P. is the recipient of a scholarship from Diabete Quebec.

Mx proteins are interferon (IFN)-induced GTPases that confer antiviral activity in many vertebrates. Mouse Mx1 accumulates in the nucleus of IFN-treated cells and mediates antiviral activity in vitro and in vivo against orthomyxoviruses, such as influenza A and Thogoto viruses. Human MxA is a cytoplasmic protein that exhibits an even broader antiviral activity in cultured cells. However, to date, its in vivo potential remained poorly investigated. To fill this knowledge gap, we created a new mouse line that carries the entire human Mx locus as a transgene. We found that high levels of MxA were induced in cultured embryonic fibroblasts from transgenic mice upon treatment with IFN-α. Further, high levels of MxA were found in most organs of transgenic mice at 24 h post treatment with recombinant IFN-α but not in organs of untreated animals, indicating faithful regulation of the human Mx locus in our transgenic mouse. Challenge experiments demonstrated that our transgenic mice are well protected from lethal infections with Thogoto virus and highly pathogenic avian influenza A virus strains. Interestingly, protection against influenza A virus strains of human origin, such as the H1N1 strains A/PR/8/34 and A/WSN/33 or the H3N2 strain A/HK/68, was only moderate. Our results provide strong indirect evidence that the Mx locus plays an important role in influenza A virus protection of humans. They further suggest that circulating human influenza virus strains have acquired adaptive mutations which permit viral replication in the presence of Mx.