Proposition d’activité pédagogique pour mieux appréhender les perspectives éthiques anthropocentrique, biocentrique

Devant une problématique socio-environnementale complexe, la collaboration entre différents acteurs de différents domaines est nécessaire. Notre postulat est que celle-ci serait facilitée si les participants étaient capables de comprendre la vision du monde de chacun des acteurs et de mieux saisir leurs différentes identités comme agents environnementaux. Ceci pourrait les aider à mieux cerner comment intervenir ensemble pour poser des gestes concrets. Dans cet article, nous proposons une act..

Cosine Effect in Ocean Models

Publisher's PDF version upon email request to any of the coauthors.International audienceThis works aims at studying the impact of the cosine terms of the Coriolis force, that are usually neglected in geophysical fluid dynamics, leading to the so-called traditional approximation. Mathematical well-posedness arguments for simplified models, as well as numerical simulations, are presented in order to suggest the use of these terms in large scale ocean modelling

Co-evolution of segregation guide DNA motifs and the FtsK translocase in bacteria: identification of the atypical Lactococcus lactis KOPS motif

Bacteria use the global bipolarization of their chromosomes into replichores to control the dynamics and segregation of their genome during the cell cycle. This involves the control of protein activities by recognition of specific short DNA motifs whose orientation along the chromosome is highly skewed. The KOPS motifs act in chromosome segregation by orienting the activity of the FtsK DNA translocase towards the terminal replichore junction. KOPS motifs have been identified in γ-Proteobacteria and in Bacillus subtilis as closely related G-rich octamers. We have identified the KOPS motif of Lactococcus lactis, a model bacteria of the Streptococcaceae family harbouring a compact and low GC% genome. This motif, 5′-GAAGAAG-3, was predicted in silico using the occurrence and skew characteristics of known KOPS motifs. We show that it is specifically recognized by L. lactis FtsK in vitro and controls its activity in vivo. L. lactis KOPS is thus an A-rich heptamer motif. Our results show that KOPS-controlled chromosome segregation is conserved in Streptococcaceae but that KOPS may show important variation in sequence and length between bacterial families. This suggests that FtsK adapts to its host genome by selecting motifs with convenient occurrence frequencies and orientation skews to orient its activity

Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis

Background and purpose Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age

Are two better than one? Analysis of an FtsK/Xer recombination system that uses a single recombinase

Bacteria harbouring circular chromosomes have a Xer site-specific recombination system that resolves chromosome dimers at division. In Escherichia coli, the activity of the XerCD/dif system is controlled and coupled with cell division by the FtsK DNA translocase. Most Xer systems, as XerCD/dif, include two different recombinases. However, some, as the Lactococcus lactis XerS/difSL system, include only one recombinase. We investigated the functional effects of this difference by studying the XerS/difSL system. XerS bound and recombined difSL sites in vitro, both activities displaying asymmetric characteristics. Resolution of chromosome dimers by XerS/difSL required translocation by division septum-borne FtsK. The translocase domain of L. lactis FtsK supported recombination by XerCD/dif, just as E. coli FtsK supports recombination by XerS/difSL. Thus, the FtsK-dependent coupling of chromosome segregation with cell division extends to non-rod-shaped bacteria and outside the phylum Proteobacteria. Both the XerCD/dif and XerS/difSL recombination systems require the control activities of the FtsKγ subdomain. However, FtsKγ activates recombination through different mechanisms in these two Xer systems. We show that FtsKγ alone activates XerCD/dif recombination. In contrast, both FtsKγ and the translocation motor are required to activate XerS/difSL recombination. These findings have implications for the mechanisms by which FtsK activates recombination

Étude des perspectives éthiques sur l'environnement : activités de dialogues pour des élèves de la fin du primaire

Le développement et le développement durable sont sujets à plusieurs critiques notamment concernant l'anthropocentrisme qu'ils véhiculent. L'éducation relative aux valeurs environnementales peut amener les enfants à s'ouvrir à d'autres perspectives éthiques sur l'environnement. Pour cela, l'enseignant devra poser des questions et mener des activités qui permettront aux élèves de réfléchir individuellement, d'échanger leurs points de vue et de faire des débats en classe autour de thèmes centraux caractéristiques des perspectives éthiques anthropocentrique, biocentrique et écocentrique. Notre cadre théorique et l'analyse-critique d'un questionnaire nous ont permis de spécifier ces thèmes (conceptions sur l'environnement et la nature, droits des êtres vivants, place des humains dans ou par rapport à la nature, avenir de l'environnement et préférences envers les trois perspectives éthiques proposées). Ils nous ont permis également de suggérer quelques questions et activités afin d'amener les enfants à envisager d'autres perspectives sur ces thèmes que celle(s) qu'ils avaient initialement

Viral sensing by RNA helicases

International audienceA key aspect of antiviral immunity is the distinction between "self" and "non-self" components. This distinction can be established through the detection of double-stranded RNA (dsRNA), a common sign of viral infection, by cytosolic RNA helicases. Depending on the organism, two major antiviral pathways can be induced by dsRNA helicases: RNA interference (RNAi) and interferon (IFN) signaling. In the RNAi pathway, dsRNAs are recognized by a Dicer protein, and are then used for the sequence-dependent recognition and subsequent degradation of the complementary viral RNAs. In the IFN signaling pathway, dsRNAs are recognized by a RIG-like receptor (RLR), which induces a signaling cascade in order to induce the expression of IFNs, cytokines and chemokines. In this review, we discuss the RNA features that can be used by the cell to detect a viral infection, the two aforementioned types of helicase-mediated sensing, as well as some viral escape mechanisms developed to avoid recognition

New Developments and Cosine Effect in the Viscous Shallow Water and Quasi-Geostrophic Equations

International audienceThe viscous Shallow Water Equations and Quasi-Geostrophic Equations are considered in this paper. Some new terms, related to the Coriolis force, are revealed thanks to a rigorous asymptotic analysis. After providing well-posedness arguments for the new models, the authors perform some numerical computations that confirm the role played by the cosine effect in various physical configurations

Comment le risque devient une évidence : praticiens, femmes enceintes et dépistage prénatal de la trisomie 21

In France as in other industrialized countries, pregnancy is regarded as a risk period. As such, a medical surveillance on a regular basis is necessary. Among all the risks that are anticipated, specific public policies have been implemented to control the risk of fetal anomaly. This paper focusses on Down’s syndrome (DS) screening programmes, in order to analyze which representations of the risk of DS are produced in consultations. How is the screening test presented to pregnant women, and accepted or declined? We observed two types of consultations: first trimester fetal ultrasound scan when the nuchal translucency measurement may indicate a risk of fetal DS, and first pregnancy consultation when doctors or midwives propose the maternal serum markers test. Although the regulatory frames of these activities and the sociotechnical settings are different, the observed practices are quite similar. Various regulations, as well as time constraints and emotional pressures, contribute to construct the importance of the DS risk and the use of screening tests as self-evident