De l'altruisme dans les bornes de l'égoïsme

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

The complete chloroplast DNA sequence of the green alga Oltmannsiellopsis viridis reveals a distinctive quadripartite architecture in the chloroplast genome of early diverging ulvophytes

BACKGROUND: The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. The basal position of the Prasinophyceae has been well documented, but the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae is currently debated. The four complete chloroplast DNA (cpDNA) sequences presently available for representatives of these classes have revealed extensive variability in overall structure, gene content, intron composition and gene order. The chloroplast genome of Pseudendoclonium (Ulvophyceae), in particular, is characterized by an atypical quadripartite architecture that deviates from the ancestral type by a large inverted repeat (IR) featuring an inverted rRNA operon and a small single-copy (SSC) region containing 14 genes normally found in the large single-copy (LSC) region. To gain insights into the nature of the events that led to the reorganization of the chloroplast genome in the Ulvophyceae, we have determined the complete cpDNA sequence of Oltmannsiellopsis viridis, a representative of a distinct, early diverging lineage. RESULTS: The 151,933 bp IR-containing genome of Oltmannsiellopsis differs considerably from Pseudendoclonium and other chlorophyte cpDNAs in intron content and gene order, but shares close similarities with its ulvophyte homologue at the levels of quadripartite architecture, gene content and gene density. Oltmannsiellopsis cpDNA encodes 105 genes, contains five group I introns, and features many short dispersed repeats. As in Pseudendoclonium cpDNA, the rRNA genes in the IR are transcribed toward the single copy region featuring the genes typically found in the ancestral LSC region, and the opposite single copy region harbours genes characteristic of both the ancestral SSC and LSC regions. The 52 genes that were transferred from the ancestral LSC to SSC region include 12 of those observed in Pseudendoclonium cpDNA. Surprisingly, the overall gene organization of Oltmannsiellopsis cpDNA more closely resembles that of Chlorella (Trebouxiophyceae) cpDNA. CONCLUSION: The chloroplast genome of the last common ancestor of Oltmannsiellopsis and Pseudendoclonium contained a minimum of 108 genes, carried only a few group I introns, and featured a distinctive quadripartite architecture. Numerous changes were experienced by the chloroplast genome in the lineages leading to Oltmannsiellopsis and Pseudendoclonium. Our comparative analyses of chlorophyte cpDNAs support the notion that the Ulvophyceae is sister to the Chlorophyceae

Improving the simulation of landfast ice by combining tensile strength and a parameterization for grounded ridges

ABSTRACT: In some coastal regions of the Arctic Ocean, grounded ice ridges contribute to stabilizing andmaintaining a landfast ice cover. Recently, a grounding scheme representing this effect on sea ice dynamicswas introduced and tested in a viscous-plastic sea ice model. This grounding scheme, based on a basalstress parameterization, improves the simulation of landfast ice in many regions such as in the East SiberianSea, the Laptev Sea, and along the coast of Alaska. Nevertheless, in some regions like the Kara Sea, the areaof landfast ice is systematically underestimated. This indicates that another mechanism such as ice archingis at play for maintaining the ice cover fast. To address this problem, the combination of the basal stressparameterization and tensile strength is investigated using a 0.258Pan-Arctic CICE-NEMO configuration.Both uniaxial and isotropic tensile strengths notably improve the simulation of landfast ice in the Kara Seabut also in the Laptev Sea. However, the simulated landfast ice season for the Kara Sea is too short com-pared to observations. This is especially obvious for the onset of the landfast ice season which systematical-ly occurs later in the model and with a slower build up. This suggests that improvements to the sea icethermodynamics could reduce these discrepancies with the data. Key Points - A grounding scheme is not enough to simulate landfast ice in Pan-Arctic simulations; - Both uniaxial and isotropic tensile strengths notably improve the simulation of landfast ice in deep coastal regions; - Simulated landfast ice season in the Kara Sea is still too short suggesting that thermodynamics should be improved

Comparing the cost-effectiveness of two- and three-dose schedules of human papillomavirus vaccination: a transmission-dynamic modelling study.

BACKGROUND: Recent evidence suggests that two doses of HPV vaccines may be as protective as three doses in the short-term. We estimated the incremental cost-effectiveness of two- and three-dose schedules of girls-only and girls & boys HPV vaccination programmes in Canada. METHODS: We used HPV-ADVISE, an individual-based transmission-dynamic model of multi-type HPV infection and diseases (anogenital warts, and cancers of the cervix, vulva, vagina, anus, penis and oropharynx). We conducted the analysis from the health payer perspective, with a 70-year time horizon and 3% discount rate, and performed extensive sensitivity analyses, including duration of vaccine protection and vaccine cost. FINDINGS: Assuming 80% coverage and a vaccine cost per dose of $85, two-dose girls-only vaccination (vs. no vaccination) produced cost/quality-adjusted life-year (QALY)-gained varying between$7900-24,300. The incremental cost-effectiveness ratio of giving the third dose to girls (vs. two doses) was below $40,000/QALY-gained when: (i) three doses provide longer protection than two doses and (ii) two-dose protection was shorter than 30 years. Vaccinating boys (with two or three doses) was not cost-effective (vs. girls-only vaccination) under most scenarios investigated. INTERPRETATION: Two-dose HPV vaccination is likely to be cost-effective if its duration of protection is at least 10 years. A third dose of HPV vaccine is unlikely to be cost-effective if two-dose duration of protection is longer than 30 years. Finally, two-dose girls & boys HPV vaccination is unlikely to be cost-effective unless the cost per dose for boys is substantially lower than the cost for girls

Nature-based coastal restoration: Development of an early-rearing production protocol of sugar kelp (Saccharina latissima Linnaeus) for bottom planting activities in the Gulf of St-Lawrence (Québec, Canada)

Successful bottom planting of indigenous macroalgae Saccharina latissima aimed at coastal restoration purposes require the mass production in controlled conditions of strongly fixed, healthy sporophytes followed by optimal transfer techniques in order to ensure viability and vigor of the young seedlings about to be directly introduced in the coastal environment. Early development of S. latissima submitted to different combinations of substrate type (natural vs artificial brick-shaped substrate), gametophyte spraying method (water-based vs binder-based) and water velocity (0.1 vs 0.2 m s-1) was evaluated during a growth trial that lasted 42 days. Overall, all experimental groups (8 in triplicate) reached the targeted length of 15 mm between 35-42 days post-seeding. No strong indications that the proposed 2×2×2 factorial design generated long lasting effects on growth and development indicators were observed (thallus length, SGR and % coverage). The observation of no persistent difference in the growth response of S. latissima under all experimental conditions, demonstrates that it is well suited for mass production of seedlings. Our results and evidenced-based practices led us to conclude that the use of an artificial substrate in combination with a binder-based gametophyte pulverization and the application of a velocity 0.2 m s-1 during early-growth could be adopted in a standardized protocol. We argue that 1) artificial substrates (uniform shape, stackable and rough surface) will most likely allow better use of a vessel’s open deck space and adherence of the developing holdfast; 2) the use of a binder may slow down the dehydration of the propagules and promote adhesiveness to the substrate during rearing, handling and transfer operations and under varying flow rates or wave actions respectively and 3) highest velocity should promote the selection of propagules with strongest attachment and thus possibly limit post-transfer dislodgement. We suggest further studies should 1) focus on identifying optimal gametophyte concentration at the spraying step, in order to reduce production costs and maximise productivity of seedling operations and 2) include biomass determination (g of tissue per cm2) in combination to the semi-quantitative density evaluation (% coverage) based on image-analysis, in order to improve our global assessment of growth

Revue d'histoire du Bas-Saint-Laurent, vol. 12 (3-4)

Mot de l'éditeur -- Au micro de CJBR -- La grande histoire de CJBR -- Jules-A. Brillant et le poste CJBR -- Avec CJBR, un bon en avant pour le Bas St-Laurent -- CJBR, l'école -- L'annonceur: un éducateur populaire -- Sandy Burgess : le journaliste que j'ai connu -- "Ce pays qui est le mien" -- Un demi-siècle d'information: que de nouvelles! -- Journaliste de père en fils à CJBR -- Le théâtre à CJBR -- 50 ans de musique à CJBR, le château fort de la mélodie française -- Poésie, théâtre, jazz et originalité avec Michel Garneau -- Les "Chroniques du dimanche", l'âge d'or de la critique culturelle à CJBR -- "Si CJBR m'était conté..." -- L'évolution technologique, un élément-clef de l'histoire des 50 ans de radiodiffusion -- La publicité à CJBR, quarante ans de croissance -- Des pionnières à CJBR -- 1958-1972, des années enrichissantes -- De Trois-Pistoles à Rimouski -- Le sport et son enracinement dans le milieu régional -- "Debout c'est l'heure", c'est Jean Brisson qui sonne le réveil -- "Par une belle journée de tempête" -- Et on repart vers la centain

Des livres et des idées - Biennale des sciences humaines et sociales 2012

"L\u27édition de sciences humaines et sociales : le cœur en danger", ainsi Sophie Barluet intitulait-elle son rapport commandé par le ministère de la Culture et de la Communication, remis en 2004. Si la question du devenir des sciences humaines et sociales n\u27est pas réductible à sa seule présence sur les tables des libraires, la vitalité du secteur est sans cesse questionnée, depuis la mort des Pères : Sartre, Foucault, Barthes, Bourdieu, Derrida…, depuis la chute du mur de Berlin, et la prégnance – comme allant de soi - du capitalisme (financier), et l\u27effacement du politique, depuis le 11 septembre 2001, entrée fracassante dans le XXIe siècle, comme il y eut Sarajevo un siècle plus tôt, depuis le bouleversement des techniques de lecture et de publication (numérique). Pour autant, la pensée est toujours féconde. De jeunes chercheurs interrogent l\u27histoire et le colonialisme pour comprendre les révolutions du Moyen-Orient, sondent l\u27économie et la finance, analysent nos sociétés. Pour autant, l\u27édition critique traduit, découvre, parfois survit, les chercheurs publient ; voir, à ce propos, l\u27ouvrage de Sophie Noël : L\u27édition indépendante critique : engagements politiques et intellectuels (Presses de l\u27enssib, novembre 2012), ainsi que les trois volumes Faire les sciences sociales aujourd\u27hui publiés par les éditions de l\u27EHESS (octobre 2012). C\u27est pour donner la parole à ceux et celles qui nous aident à comprendre le monde que l\u27enssib, avec la librairie Passages, l\u27école des hautes études en sciences sociales (EHESS) et la bibliothèque municipale de Lyon, en collaboration avec la Fondation de la Maison des sciences de l\u27homme (FMSH), ont organisé cette première biennale des sciences humaines et sociales, dont le thème (générique) est "penser la crise"