21 research outputs found

    The Fourth SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-4)

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    Ten international laboratories specializing in the determination of marine pigment concentrations using high performance liquid chromatography (HPLC) were intercompared using in situ samples and a mixed pigment sample. Although prior Sea-viewing Wide Field-of-view Sensor (SeaWiFS) High Performance Liquid Chromatography (HPLC) Round-Robin Experiment (SeaHARRE) activities conducted in open-ocean waters covered a wide dynamic range in productivity, and some of the samples were collected in the coastal zone, none of the activities involved exclusively coastal samples. Consequently, SeaHARRE-4 was organized and executed as a strictly coastal activity and the field samples were collected from primarily eutrophic waters within the coastal zone of Denmark. The more restrictive perspective limited the dynamic range in chlorophyll concentration to approximately one and a half orders of magnitude (previous activities covered more than two orders of magnitude). The method intercomparisons were used for the following objectives: a) estimate the uncertainties in quantitating individual pigments and higher-order variables formed from sums and ratios; b) confirm if the chlorophyll a accuracy requirements for ocean color validation activities (approximately 25%, although 15% would allow for algorithm refinement) can be met in coastal waters; c) establish the reduction in uncertainties as a result of applying QA procedures; d) show the importance of establishing a properly defined referencing system in the computation of uncertainties; e) quantify the analytical benefits of performance metrics, and f) demonstrate the utility of a laboratory mix in understanding method performance. In addition, the remote sensing requirements for the in situ determination of total chlorophyll a were investigated to determine whether or not the average uncertainty for this measurement is being satisfied

    An international intercomparison of stable carbon isotope composition measurements of dissolved inorganic carbon in seawater

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    We report results of an intercomparison of stable carbon isotope ratio measurements in seawater dissolved inorganic carbon (ÎŽ 13C‐DIC) which involved 16 participating laboratories from various parts of the world. The intercomparison involved distribution of samples of a Certified Reference Material for seawater DIC concentration and alkalinity and a preserved sample of deep seawater collected at 4000 m in the northeastern Atlantic Ocean. The between‐lab standard deviation of reported uncorrected values measured with diverse analytical, detection, and calibration methods was 0.11‰ (1σ ). The multi‐lab average ÎŽ 13C‐DIC value reported for the deep seawater sample was consistent within 0.1‰ with historical measured values for the same water mass. Application of a correction procedure based on a consensus value for the distributed reference material, improved the between‐lab standard deviation to 0.06‰. The magnitude of the corrections were similar to those used to correct independent data sets using crossover comparisons, where deep water analyses from different cruises are compared at nearby locations. Our results demonstrate that the accuracy/uncertainty target proposed by the Global Ocean Observing System (±0.05‰) is attainable, but only if an aqueous phase reference material for ÎŽ 13C‐DIC is made available and used by the measurement community. Our results imply that existing Certified Reference Materials used for seawater DIC and alkalinity quality control are suitable for this purpose, if a “Certified” or internally consistent “consensus” value for ÎŽ 13C‐DIC can be assigned to various batches.publishedVersio

    Water mass transport and transformation in the western SPNA, Cruise No. MSM74, May 25 - June 26, 2018, St. John's (Canada) - Reykjavik (Iceland), Western SPNA transport

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    The scientific program of the MARIA S. MERIAN MSM74 expedition was dedicated to studies on the intensity of water mass transformation and the southward transport of water masses in the boundary current systems off Labrador and at the southern tip of Greenland. During the expedition we recovered 17/deployed 8 deep sea moorings. Measurements of the vertical structure of temperature, salinity, density, oxygen, optical properties and the flow along selected sections have been surveyed during the MSM74 expedition. Close to the surface, permanent registrations are carried out with the thermosalinograph (temperature, salinity) and meteorological data are continuously collected. Flow measurements up to 1000m depth are performed with the ships installed ADCPs. The expedition is a contribution to national (RACE) and international projects (OSNAP, AtlantOS)

    La criminalité et les transports publics

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    Bradet Claire, Normandeau André. La criminalité et les transports publics. In: Déviance et société. 1987 - Vol. 11 - N°1. pp. 105-122

    Searching for intra-locus sexual conflicts in the three-spined stickleback (Gasterosteus aculeatus) genome

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    International audienceDifferences between sexes in trait fitness optima can generate intra-locus sexual conflicts that have the potential to maintain genetic diversity through balancing selection. However, these differences are unlikely to be associated with strong selective coefficients and are challenging to detect. Additionally, recent studies have highlighted that duplications on sexual chromosomes can create artefactual signals of intra-locus sexual conflicts. Thus, testing the relationship between intra-locus sexual conflicts and balancing selection requires stringent filtering of duplicated regions, and dedicated methods to detect loci with low levels of intersex differentiation. In this study, we investigated intra-locus sexual conflicts in the three-spined stickleback using whole genome sequencing (mean coverage = 12X) of 50 females and 49 males from an anadromous population in the St. Lawrence River, Québec, Canada. After stringent filtering of duplications from the sex chromosomes, we compared three methods to detect intra-locus sexual conflicts. We found only two genomic regions under potential intra-locus sexual conflict that also showed signals of balancing selection. Overall, our results suggest that most intra-locus sexual conflicts do not drive long-term balancing selection and are most likely transient

    database_genotype_size

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    Includes information on origin, sex, genotype and wing length for all the 1967 wild samples genotyped in the 20 populations described in the article. Wing length is missing when the specimen wings was too damaged to be measure accurately

    Met_phased_dryad_March18.phy

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    Sequences of Met locus aligned and phased (phylip format

    Rib_phased_Dryad_March18.phy

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    Sequences of Rib locus aligned and phased (phylip format

    Rib_unphased_Dryad_March2018

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    Sequences of Rib locus aligned and unphase

    Adh_unphased_Dryad_march18

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    Sequences of Adh locus aligned and unphase
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