541 research outputs found

    Extension de l'aire de distribution connue de la Musaraigne fuligineuse, Sorex fumeus, dans le nord-est du Québec

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    La Musaraigne fuligineuse (Sorex fumeus) figure sur la liste des espĂšces de la faune vertĂ©brĂ©e susceptibles d’ĂȘtre dĂ©signĂ©es menacĂ©es ou vulnĂ©rables au QuĂ©bec. Le 7 juin 1999, nous avons rĂ©coltĂ© un individu mort en bordure de la riviĂšre Saint-Nicolas, Ă  Godbout, dans la rĂ©gion de la CĂŽte Nord. Cette observation constitue une extension de l’aire de rĂ©partition connue de l’espĂšce d’environ 200 km vers le nord-est

    Fernand Nouvion, génie de la traction électrique

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    De Marc Seguin, l’un des inventeurs de la locomotive Ă  vapeur, Ă  AndrĂ© Chapelon qui l’a menĂ©e Ă  son apogĂ©e un siĂšcle plus tard, on sait le rĂŽle majeur tenu par les ingĂ©nieurs français dans l’histoire des chemins de fer. AndrĂ© Chapelon, Genius of French Steam est le titre de la premiĂšre biographie de l’illustre vaporiste qui, s’il n’avait inventĂ© la locomotive Ă  vapeur, en avait poussĂ© les perfectionnements Ă  un degrĂ© tel que certains dĂ©ploraient de la voir remplacĂ©e un jour par sa concurrente..

    La création du CNRS

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    How CNRS came to be The CNRS was born six weeks after World War II started. Its birth certificate was an October 19, 1939 decree, intended to “coordinate laboratories” activities in order to draw a higher output from scientific research. This gave the CNRS the authority to merge a scientific fund supporting academic research (The National Fund for Scientific Research) and an institute carrying out the research programs started by the scientists in order to develop scientific research for the war (the National Center for Applied Scientific Research). Physics became an essential part in scientific organization, both in basic research (in astrophysics, in corpuscular physics...) and, in the Programs necessary to the Ministry of Defense (in fields such as atomic fission, ultra-high, frequencies, etc.). The war, followed by French defeat and German occupation reinforced the priority given to finalized research. French research setup was later modified at the end of the war. In fact, the CNRS - created and maintained under the National Education Ministry’s supervision - had not succeeded in coordinating the main State services. New organizations were being created, such as the National Hygiene Institute (later called INSERM) in 1941; the National Center of Telecommunication Studies in 1944; the Atomic Energy Commission in (1945, etc. Simultaneously, the academic community was asserting its wish to regain a directing power that scientists had taken away from it. A law was voted on August 12, 1945, proclaiming that the CNRS’s objective was to support pure science and academic research. This law also established that a “science parliament”, the National Committee, would be in charge of defining the CNRS’ main orientations. However, the functioning of such an intermediary agency ran against the physicists’ interests. Physics had become an extensive science which could not be developed with meager budget allocations typically endowed to a science fund. And physicists were not long in creating new institutes to free themselves from the CNRS’ supervision

    Un demi-siÚcle de génétique de la levure au CNRS, de la biologie moléculaire à la génomique

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    The singular fate of genetics in the history of French biology Fifteen years ago, the Journal of the History of Biology published an article that was significant in the historical epistemology of the 20th century. Entitled « The Single Fate of Genetics in the Biological History of France, » and inspired by the theories of philosopher G. Canguilhem, the three authors (R. Burian, J. Gayon, D. Zallen) described the manner in which genetics was developed in France on the margins of the mainstream chromosomal genetics of T. H. Morgan. They focused on the scientific career of Boris Ephrussi, an embryologist-physiologist with a fellowship at the Institut de biologie physio-chimique (IBPC). Ephrussi became the first person to hold a chair in genetics at the university level. Despite the intellectual resistance of naturalists on the faculty of sciences or at the National Museum of Natural History, Ephrussi and his student Piotr Slonimski introduced the new life science to the CNRS. Shortly after their foreign counterparts in the field, the French biologists created a new discipline under the contested name “molecular biology” which came from the convergence of genetics and biochemistry. The choice to use yeast for an experimental material permitted geneticists at the CNRS to reveal cytoplasmic (not chromosomal) genetic structure that would, twenty years later, lead to remarkable developments at the Centre de gĂ©nĂ©tique molĂ©culaire at Gif-sur-Yvette. This group of laboratories rapidly acquired an international renown in the study of phenomena of genetic regulation. They played an important role in the first sequencing program for a eukaryote (the yeast), which opened the way for post-genomics

    The Mink Frog, Rana septentrionalis, in Southeastern Labrador

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    Mink Frogs (Rana septentrionalis) were collected at three new localities in southeastern Labrador in 2003 and 2005, extending the known range of the species about 200 km to the east, to the limits of the coast.La Grenouille du Nord (Rana septentrionalis) a Ă©tĂ© trouvĂ©e dans trois nouvelles localitĂ©s dans le sud-est du Labrador en 2003 et 2005. Ces mentions Ă©largissent l’aire de rĂ©partition connue de l’espĂšce d’environ 200 km vers l’est, aux limites de la cĂŽte de l’OcĂ©an Atlantique

    A Herpetological Survey of the James Bay Area of Québec and Ontario

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    In May-June 2002, as part of a survey of a variety of taxa in the James Bay region of Ontario and QuĂ©bec, we surveyed the poorly documented herpetofauna of this region. In Ontario we visited sites near Moosonee that FWS had previously surveyed in 1971-1972, and continued ongoing herpetological monitoring around Cochrane. In QuĂ©bec we surveyed the inland James Bay Road, and roads to four settlements along the coast. American Toad (Anaxyrus americanus), Spring Peeper (Pseudacris crucifer), and Wood Frog (Lithobates sylvaticus) were widespread and abundant throughout. Blue-spotted Salamander (Ambystoma laterale) and Garter Snake (Thamnophis sirtalis) were widespread and common in QuĂ©bec and at the study site near Cochrane. We obtained the first taped calls and voucher specimen of the Boreal Chorus Frog (Pseudacris maculata) from QuĂ©bec, and failed to find it at the settlement and airport of Moosonee where it had been present in 1972. A significant range extension was for the Two-lined Salamander (Eurycea bislineata), which we found 200 km north of its previously known range in northwestern QuĂ©bec. Despite extensive searches, the species was not found north of 52°05'N. The Mink Frog (Lithobates septentrionalis) was widespread and relatively common in QuĂ©bec, but was sought but not found in Ontario. The Leopard Frog (Lithobates pipiens) was only found at two QuĂ©bec sites, including one where it was reported in 1974, but it has not been found at any of the Ontario sites where it was found in the 1970's. We present some suggestions for the further study of the herpetofauna of the area, and review evidence for contacts between eastern and western lineages of widespread species.En mai et juin 2002, dans le cadre d'un inventaire faunique dans la rĂ©gion de la baie James, en Ontario et au QuĂ©bec, nous avons inventoriĂ© la faune herpĂ©tologique, laquelle est trĂšs peu documentĂ©e dans cette rĂ©gion. En Ontario nous avons visitĂ© des sites prĂšs de Moosonee, que l'un de nous (FWS) avait inventoriĂ© en 1971-1972, puis nous sommes allĂ©s aux environs de Cochrane. Au QuĂ©bec l'inventaire s'est majoritairement fait le long de la route de la baie James et des routes d'accĂšs aux villages. Le Crapaud d'AmĂ©rique (Anaxyrus americanus), la Rainette crucifĂšre (Pseudacris crucifer) et la Grenouille des bois (Lithobates sylvaticus) sont rĂ©pandus et communs sur toute l'aire d'Ă©tude. La Salamandre Ă  points bleus (Ambystoma laterale) et la Couleuvre rayĂ©e (Thamnophis sirtalis) sont rĂ©pandues et communes au QuĂ©bec et prĂšs de Cochrane. Nous avons rĂ©alisĂ© les premiers enregistrements de chants et collectĂ© le premier spĂ©cimen de Rainette faux-grillon borĂ©ale (Pseudacris maculata) pour le QuĂ©bec, et n'avons pu la retrouver Ă  Moosonee et Ă  son aĂ©roport, oĂč l'espĂšce avait Ă©tĂ© recensĂ©e en 1972. La seule extension d'aire significative a Ă©tĂ© faite pour la Salamandre Ă  deux lignes (Eurycea bislineata), trouvĂ©e Ă  200 km au nord de son aire de rĂ©partition connue dans le nord-ouest du QuĂ©bec. MalgrĂ© des recherches intensives, elle n'a pas Ă©tĂ© vue plus au nord que 52°05'N. La Grenouille du Nord (Lithobates septentrionalis), est rĂ©pandue et relativement commune au QuĂ©bec mais n'a pu ĂȘtre trouvĂ©e en Ontario. La Grenouille lĂ©opard (Lithobates pipiens) a seulement Ă©tĂ© recensĂ©e Ă  deux endroits au QuĂ©bec, incluant un site oĂč l'espĂšce avait Ă©tĂ© trouvĂ©e en 1974, mais n'a pu ĂȘtre trouvĂ©e en Ontario dans les sites oĂč on la retrouvait dans les annĂ©es '70. Nous prĂ©sentons quelques suggestions de futures Ă©tudes sur l'herpĂ©tofaune de cette rĂ©gion, et discutons des liens entre les formes de l'ouest et celles de l'est pour les espĂšces rĂ©pandues

    Specific fibre composition and metabolism of the rectus abdominis muscle of bovine Charolais cattle

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    Background: An important variability of contractile and metabolic properties between muscles has been highlighted. In the literature, the majority of studies on beef sensorial quality concerns M. longissimus thoracis. M. rectus abdominis (RA) is easy to sample without huge carcass depreciation and may appear as an alternative to M. longissimus thoracis for fast and routine physicochemical analysis. It was considered interesting to assess the muscle fibres of M. rectus abdominis in comparison with M. longissimus thoracis (LT) and M. triceps brachii (TB) on the basis of metabolic and contractile properties, area and myosin heavy chain isoforms (MyHC) proportions. Immunohistochemical, histochemical, histological and enzymological techniques were used. This research concerned two populations of Charolais cattle: RA was compared to TB in a population of 19 steers while RA was compared to LT in a population of 153 heifers. Results: RA muscle had higher mean fibre areas (3350 ÎŒm2 vs 2142 to 2639 ÎŒm2) than the two other muscles. In RA muscle, the slow-oxidative fibres were the largest (3957 ÎŒm2) and the fast-glycolytic the smallest (2868 ÎŒm2). The reverse was observed in TB muscle (1725 and 2436 ÎŒm2 respectively). In RA muscle, the distinction between fast-oxidative-glycolytic and fast-glycolytic fibres appeared difficult or impossible to establish, unlike in the other muscles. Consequently the classification based on ATPase and SDH activities seemed inappropriate, since the FOG fibres presented rather low SDH activity in this muscle in comparison to the other muscles of the carcass. RA muscle had a higher proportion of I fibres than TB and LT muscles, balanced by a lower proportion either of IIX fibres (in comparison to TB muscle) or of IIA fibres (in comparison to LT muscle). However, both oxidative and glycolytic enzyme activities were lower in RA than in TB muscle, although the LDH/ICDH ratio was higher in RA muscle (522 vs 340). Oxidative enzyme activities were higher in RA than in LT muscle, whereas glycolytic enzyme activity was lower. In RA muscle, contractile and metabolic properties appeared to be less well-correlated than in the two other muscles. Conclusions: RA muscle has some particularities in comparison to the LT and TB muscles, especially concerning the unusual large cross-section surface of SO fibres and the very low oxidative activity of intermediate IIA fibres

    La viande du futur sera-t-elle produite in vitro ?

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    La production de viande artificielle par culture de cellules est proposĂ©e par certains scientifiques comme une des solutions pour rĂ©pondre aux grands enjeux de l’élevage : i) rĂ©duire le mal-ĂȘtre supposĂ© des animaux dans les Ă©levages modernes, voire ne pas tuer les animaux pour les manger, ii) rĂ©duire la possible dĂ©gradation de l’environnement par l’élevage et iii) rĂ©duire la faim dans le monde en augmentant le niveau des ressources protĂ©iques alimentaires. La viande artificielle supprimerait en effet le mal-ĂȘtre supposĂ© des animaux liĂ© Ă  l’élevage et permettrait de ne pas abattre les animaux pour les manger. L’impact environnemental de la viande artificielle est difficile Ă  Ă©valuer en l’absence de donnĂ©es sur le fonctionnement d’une usine de production. La viande artificielle prĂ©senterait toutefois un intĂ©rĂȘt modĂ©rĂ© pour rĂ©duire les gaz Ă  effet de serre et la pollution par les nitrates, un intĂ©rĂȘt limitĂ© quant Ă  l’utilisation des Ă©nergies fossiles, voire trĂšs limitĂ© pour limiter les besoins en eau, mais elle libĂ©rerait des terres cultivables. Elle entraĂźnerait probablement dans l’eau des rĂ©sidus de molĂ©cules de synthĂšse. De nombreux experts estiment que les causes de la malnutrition actuelle de certaines populations sont multiples et ne sont pas directement liĂ©es Ă  un manque de ressources alimentaires. Bien que la culture de cellules soit couramment pratiquĂ©e en laboratoire, il existe des verrous techniques importants Ă  lever pour une production Ă  grande Ă©chelle, tels que le coĂ»t rĂ©dhibitoire des technologies actuelles et le manque de ressemblance du produit obtenu Ă  de la viande issue d’animaux. Sur le plan nutritionnel, la viande artificielle ne prĂ©sente pas d’avantage particulier par rapport Ă  un autre aliment Ă©laborĂ© Ă  partir de l’ensemble des nutriments nĂ©cessaires Ă  sa production. Les critĂšres d’acceptabilitĂ© de la viande artificielle renvoient, d’une part, Ă  des questions d’ordre moral ou Ă©thique concernant la technologie et les inquiĂ©tudes qu’elle soulĂšve, et d’autre part, Ă  des considĂ©rations classiques relatives aux produits alimentaires (prix, qualitĂ©, naturalitĂ©...). Par le passĂ©, les expĂ©riences de substitution des protĂ©ines animales par des produits analogues ont Ă©chouĂ© en raison, notamment, de contraintes Ă©conomiques, du temps nĂ©cessaire pour l’éventuelle acceptation des produits par les consommateurs et pour la dĂ©livrance des autorisations de mise sur le marchĂ©. Face aux questionnements importants concernant l’élevage, la production de viande artificielle ne prĂ©sente pas aujourd’hui d’avantages majeurs par comparaison Ă  la viande naturelle ou Ă  d’autres alternatives possibles telles que rĂ©Ă©quilibrer notre alimentation en diversifiant les sources de protĂ©ines vĂ©gĂ©tales et animales, ou encore dĂ©velopper des systĂšmes d’élevage plus respectueux des animaux et de l’environnement

    Parvovirus 4 in French in-patients: a study of haemodialysis and lung transplant cohorts

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    International audienceThe epidemiology and the clinical implication of human parvovirus 4 (PARV4) in human populations is still under evaluation. The distribution of PARV4 DNA was determined in cohorts of French haemodialysis and lung transplant patients. Plasma samples (n=289) were tested for PARV4 by real-time PCR assay (ORF2), and amplification products selected at random were sequenced. Analysis of available serological and biological markers was also undertaken. Fifty-seven samples out of 185 (30.8%) were positive for PARV4 DNA in the cohort of haemodialysis patients. A higher prevalence of the virus was identified in individuals with markers of HBV infection. PARV4 was also identified in 14 out of 104 samples (13.5%) from lung transplant recipients, with no clear-cut association with available clinical markers. Point mutations located on the zone of real-time detection were identified for some amplification products. This study describes the detection of PARV4 in the blood of haemodialysis and lung transplanted patients with significant difference in prevalence in these two cohorts. Further studies will be needed in order to understand better both the potential implication in host health and the natural history of this virus
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