Relationships between magmatism and lithosphere-asthenosphere structure in the Western Mediterranean and implications for geodynamics

Shear-wave (V _S ) tomography along transects across the Western-Central Mediterranean area reveals heterogeneous lateral and vertical physical characteristics in the lithosphere-asthenosphere system (LAS). A 50 km thick low velocity layer (LVL), with V _S ∼ 4.0–4.2 km/sec, typical of low rigidity fluid-bearing mantle material, is observed at a depth of about 70–120 km from offshore Provence, to Sardinia and the Central Tyrrhenian Sea. This LVL, enclosed between higher velocity mantle rocks, rises to a depth of less than 30 km below the recent and active volcanoes of Central Italy and the Southern Tyrrhenian Sea, where a maximum in the heath flow is observed. The LVL is absent beneath Southeastern France and the northern border of the African foreland. In the Balearic Sea-Sardinia-Central Tyrrhenian section, the depth of LVL corresponds to pressure conditions of minimum temperature of peridotite+CO₂+H₂O solidus, consistent with conditions where fluid loss from the slab and mantle flow over the subducting plate favor significant melt generation above steep, west-dipping subduction zones. It is suggested that LVL in the Balearic-Tyrrhenian domains is the result of mantle contamination and melting left behind by the eastward retreating Adriatic-Ionian subducting plates from Oligo-Miocene to present. This layer also marks a discontinuity between the lithospere and underlying mantle behind the subduction zone, favoring detachment and westward drift of the lithosphere, and consequent opening of backarc basins. These data support the hypothesis that the orogenic Oligocene to Quaternary volcanism in the Western Mediterranean area is the effect of shallow mantle processes, and argue against the presence of deep mantle plumes. A shallow-mantle origin is also suggested for the EM1-type Plio-Quaternary anorogenic magmatism in Sardinia and for the FOZO-DMM-type magmatism on the northern margin of the African foreland.      

Isolation and characterization of microsatellite markers for the threatened African endemic tree species Pterocarpus erinaceus Poir.

To study the genetic diversity and structure of the forest species Pterocarpus erinaceus Poir., seventeen polymorphic nuclear microsatellite markers were isolated and characterized, using next‐generation sequencing. Three hundred and sixty‐five (365) individuals were analyzed within fifteen (15) West African populations. The number of alleles for these loci varied from 4 to 30, and the heterozygosity varied from 0.23 to 0.82. The seventeen (17) primers designed here will allow characterizing the genetic diversity of this threaten species on its natural stands and to better understand the population differentiation mechanisms shaping it.     

Beyond working hours: part I. Genesis and current difficulties

The roots of the working hours mandate and controversy are outlined, the effect on resident education is described, and the service versus education equation is defined.     

Infections and coinfections of questing Ixodes ricinus ticks by emerging zoonotic pathogens in Western Switzerland

In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and "Candidatus Neoehrlichia mikurensis" were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.     

Molecular signatures of cardiac defects in down syndrome lymphoblastoid cell lines suggest altered ciliome and hedgehog pathways

Forty percent of people with Down syndrome exhibit heart defects, most often an atrioventricular septal defect (AVSD) and less frequently a ventricular septal defect (VSD) or atrial septal defect (ASD). Lymphoblastoid cell lines (LCLs) were established from lymphocytes of individuals with trisomy 21, the chromosomal abnormality causing Down syndrome. Gene expression profiles generated from DNA microarrays of LCLs from individuals without heart defects (CHD(-); n?=?22) were compared with those of LCLs from patients with cardiac malformations (CHD(+); n?=?21). After quantile normalization, principal component analysis revealed that AVSD carriers could be distinguished from a combined group of ASD or VSD (ASD+VSD) carriers. From 9,758 expressed genes, we identified 889 and 1,016 genes differentially expressed between CHD(-) and AVSD and CHD(-) and ASD+VSD, respectively, with only 119 genes in common. A specific chromosomal enrichment was found in each group of affected genes. Among the differentially expressed genes, more than 65% are expressed in human or mouse fetal heart tissues (GEO dataset). Additional LCLs from new groups of AVSD and ASD+VSD patients were analyzed by quantitative PCR; observed expression ratios were similar to microarray results. Analysis of GO categories revealed enrichment of genes from pathways regulating clathrin-mediated endocytosis in patients with AVSD and of genes involved in semaphorin-plexin-driven cardiogenesis and the formation of cytoplasmic microtubules in patients with ASD-VSD. A pathway-oriented search revealed enrichment in the ciliome for both groups and a specific enrichment in Hedgehog and Jak-stat pathways among ASD+VSD patients. These genes or related pathways are therefore potentially involved in normal cardiogenesis as well as in cardiac malformations observed in individuals with trisomy 21.     

The ageing surgeon

Why do some surgeons retire (or not), and perhaps more importantly, when should some surgeons retire? Interviews were conducted with 21 senior plastic surgeons to determine why plastic surgeons choose not to retire. In an effort to answer the second question (When should surgeons retire?), an analogy is constructed between surgeons and commercial airline pilots.