Where are you from, stranger? The enigmatic biogeography of North African pond turtles (Emys orbicularis) .

Abstract The European pond turtle (Emys orbicularis) is a Nearctic element in the African fauna and thought to have invaded North Africa from the Iberian Peninsula. All North African populations are currently identified with the subspecies E. o. occidentalis. However, a nearly range-wide sampling in North Africa used for analyses of mitochondrial and microsatellite DNA provides evidence that only Moroccan populations belong to this taxon, while eastern Algerian and Tunisian pond turtles represent an undescribed distinct subspecies. These two taxa are most closely related to E. o. galloitalica with a native distribution along the Mediterranean coast of northern Spain through southern France to western and southern Italy. This group is sister to a clade comprising several mitochondrial lineages and subspecies of E. orbicularis from Central and Eastern Europe plus Asia, and the successive sisters are E. o. hellenica and E. trinacris. Our results suggest that E. orbicularis has been present in North Africa longer than on the Iberian Peninsula and that after an initial invasion of North Africa by pond turtles from an unknown European source region, there was a phase of diversification in North Africa, followed by a later re-invasion of Europe by one of the African lineages. The differentiation of pond turtles in North Africa parallels a general phylogeographic paradigm in amphibians and reptiles, with deeply divergent lineages in the western and eastern Maghreb. Acknowledging their genetic similarity, we propose to synonymize the previously recognized Iberian subspecies E. o. fritzjuergenobsti with E. o. occidentalis sensu stricto. The seriously imperiled Moroccan populations of E. o. occidentalis represent two Management Units different in mitochondrial haplotypes and microsatellite markers. The conservation status of eastern Algerian pond turtles is unclear, while Tunisian populations are endangered. Considering that Algerian and Tunisian pond turtles represent an endemic taxon, their situation throughout the historical range should be surveyed to establish a basis for conservation measures

Catena-Poly[[[4-amino-3,5-bis­(pyridin-2-yl)-4H-1,2,4-triazole-κ2N1,N5](di­cyanamido-κN)copper(II)]-μ2-dicyan­amido-κ2N:N'] : coordination polymer chains linked into a bilayer by hydrogen bonds and π-π Stacking interactions

The authors acknowledge the Algerian DG–RSDT (Direction Generale de la Recherche Scientifique et du Developpement Technologique) and the Algerian ATRST (Agence Thematique de Recherche en Sciences et Technologie; PNR project) for financial support.In the title compound, [Cu(C2N3)2(C12H10N6)]n or [Cu(dca)2(abpt)]n, where abpt is 4-amino-3,5-bis(pyridin-2-yl)-H-1,2,4-triazole and dca is the dicyanamide anion, the CuII centre is five-coordinate with an approximately square-pyramidal geometry. One of the two dicyanamide ligands is a terminal ligand, but the other one acts as a μ1,5-bridging ligand between pairs of CuII centres, so generating a one-dimensional coordination polymer. A combination of N - H⋯N and C - H⋯N hydrogen bonds, augmented by π-π stacking interactions, links the coordination polymer chains into a bilayer structure. Comparisons are made with some related CuII complexes containing dca ligands and heteroaromatic co-ligands.Publisher PDFPeer reviewe

Accelerated Potts model for grain growth - Application to an IF steel

International audienceA modification of the Potts model for grain growth is presented. We add to the site energy a grain size factor that favors growth of large grains and whose magnitude has been optimized with respect to various aspects. The motivation for such a modification as well as the consequences in term of calculation speed are presented. The capabilities of this modified model are checked by comparing several characteristics of the microstructures obtained after various grain growth simulations with experimental data obtained for an IF steel. One large EBSD map, made at the end of the primary recrystallization, is used directly as the initial image for the calculations. A second EBSD map, obtained after grain growth (with a mean diameter of the grains about twice the initial value) was used for comparisons between the simulations and the experiment. The grain size distribution, the grain boundary character distribution and the crystallographic texture are reproduced rather well with this modified model using a moderate grain size factor effect. Also the speedup of the calculation is quite significant

Catena-Poly[[[4-amino-3,5-bis­(pyridin-2-yl)-4H-1,2,4-triazole-κ²N¹,N⁵](di­cyanamido-κN)copper(II)]-μ₂-dicyan­amido-κ₂N:N']:coordination polymer chains linked into a bilayer by hydrogen bonds and π-π Stacking interactions

In the title compound, [Cu(C2N3)2(C12H10N6)]n or [Cu(dca)2(abpt)]n, where abpt is 4-amino-3,5-bis(pyridin-2-yl)-H-1,2,4-triazole and dca is the dicyanamide anion, the CuII centre is five-coordinate with an approximately square-pyramidal geometry. One of the two dicyanamide ligands is a terminal ligand, but the other one acts as a μ1,5-bridging ligand between pairs of CuII centres, so generating a one-dimensional coordination polymer. A combination of N - H⋯N and C - H⋯N hydrogen bonds, augmented by π-π stacking interactions, links the coordination polymer chains into a bilayer structure. Comparisons are made with some related CuII complexes containing dca ligands and heteroaromatic co-ligands.</p

Crystal structure of π-cyanido-12κ2NC-dicyanido-1κC,2κC-bis(quinolin-8-amine-1κ2N,N')-2-silver(I)-1-silver(II) rare occurrence of a mixed-valence AgI,II compound

International audienceThe title dinuclear complex, [Ag2(CN)3(C9H8N2)2], may be considered as an AgII compound with the corresponding metal site coordinated by two bidentate quinolin-8-amine molecules, one cyanide group and one dicyanidoargentate(I) anion, [Ag(CN)2]-. Since this latter ligand contains an AgI atom, the complex should be a class 1 or class 2 mixed-valence compound, according to the Robin- Day classification. The AgII atom is six-coordinated in a highly distorted octahedral geometry, while the AgI atom displays the expected linear geometry. In the crystal, the amino groups of the quinolin-8-amine ligands form N-H⋯N hydrogen bonds with the N atoms of the non-bridging cyanide ligands, forming a two-dimensional network parallel to (102). The terminal cyanide ligands are not engaged in polymeric bonds and the title compound is an authentic molecular complex. The title molecule is thus a rare example of a stable AgI,II complex, and the first mixed-valence AgI,II molecular complex characterized by X-ray diffraction

Crystal structure of π-cyanido-12κ2NC-dicyanido-1κC,2κC-bis(quinolin-8-amine-1κ2N,N')-2-silver(I)-1-silver(II) rare occurrence of a mixed-valence AgI,II compound

International audienceThe title dinuclear complex, [Ag2(CN)3(C9H8N2)2], may be considered as an AgII compound with the corresponding metal site coordinated by two bidentate quinolin-8-amine molecules, one cyanide group and one dicyanidoargentate(I) anion, [Ag(CN)2]-. Since this latter ligand contains an AgI atom, the complex should be a class 1 or class 2 mixed-valence compound, according to the Robin- Day classification. The AgII atom is six-coordinated in a highly distorted octahedral geometry, while the AgI atom displays the expected linear geometry. In the crystal, the amino groups of the quinolin-8-amine ligands form N-H⋯N hydrogen bonds with the N atoms of the non-bridging cyanide ligands, forming a two-dimensional network parallel to (102). The terminal cyanide ligands are not engaged in polymeric bonds and the title compound is an authentic molecular complex. The title molecule is thus a rare example of a stable AgI,II complex, and the first mixed-valence AgI,II molecular complex characterized by X-ray diffraction