20 research outputs found

    Beaver Research in the Uvs Nuur Region

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    In 1985, 1988, and 2002 Castor fiber birulai was introduced to the Tes Gol of the Uvs Nuur basin in North-western Mongolia. The beavers migrated through the Republic of Tyva and settled in the middle part of Tes Gol near the Tyvinian-Mongolian border. About 10 colonies were recorded in this region in 2002. Strict protection of Castor fiber birulai has to be ensured in Mongolia and the Republic of Tyva in future

    Assessment of Three Mitochondrial Genes (16S, Cytb, CO1) for Identifying Species in the Praomyini Tribe (Rodentia: Muridae)

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    The Praomyini tribe is one of the most diverse and abundant groups of Old World rodents. Several species are known to be involved in crop damage and in the epidemiology of several human and cattle diseases. Due to the existence of sibling species their identification is often problematic. Thus an easy, fast and accurate species identification tool is needed for non-systematicians to correctly identify Praomyini species. In this study we compare the usefulness of three genes (16S, Cytb, CO1) for identifying species of this tribe. A total of 426 specimens representing 40 species (sampled across their geographical range) were sequenced for the three genes. Nearly all of the species included in our study are monophyletic in the neighbour joining trees. The degree of intra-specific variability tends to be lower than the divergence between species, but no barcoding gap is detected. The success rate of the statistical methods of species identification is excellent (up to 99% or 100% for statistical supervised classification methods as the k-Nearest Neighbour or Random Forest). The 16S gene is 2.5 less variable than the Cytb and CO1 genes. As a result its discriminatory power is smaller. To sum up, our results suggest that using DNA markers for identifying species in the Praomyini tribe is a largely valid approach, and that the CO1 and Cytb genes are better DNA markers than the 16S gene. Our results confirm the usefulness of statistical methods such as the Random Forest and the 1-NN methods to assign a sequence to a species, even when the number of species is relatively large. Based on our NJ trees and the distribution of all intraspecific and interspecific pairwise nucleotide distances, we highlight the presence of several potentially new species within the Praomyini tribe that should be subject to corroboration assessments

    Expérience URBCAP Nantes ' 99

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    Eval-PDU: urban traffic and its environmental impacts modelling to assess Urban Mobility Master Plan : Conception of a methodology based on the Nantes case

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    International audienceThe Eval-PDU research, funded by French National Research Agency' program Sustainable City, aims at testing methodologies for Strategic Environmental Assessment of Urban Mobility Master Plans with an application to Nantes Metropolis. The general approach used for this interdisciplinary research consists in combining several modelling of flows: first vehicles flows in the city, then the flows of atmospheric pollutants and noise pollution resulting from the traffic. In front of phenomena that are quite impossible to be precisely measured considering their micro-local diversity, modelling seems the only solution to estimate the effect of transport policies on the urban environment (in comparison with a reference situation where they are not applied) and thus to enlighten collective action in order to minimize negative externalities

    Sulfur-containing species (sulfate and methansulfonate) in coastal Antarctic aerosol and precipitation

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    The concentrations of sulfur-containing species (sulfate and methanesulfonate (MSA)) of aerosols collected at three coastal Antarctic sites (Neumayer, Dumont d'Urville, and Halley) have been studied in order to investigate the natural sulfur cycle at high southern latitudes. The multiple-year data sets indicate annual mean concentrations of MSA and non-sea-salt (nss) sulfate of 38 and 151 ng m(-3) at Neumayer (1983-1995) and 20 and 147 ng m(-3) at Dumont d'Urville (1991-1995). On the basis of the study of a more limited time period (1991 and 1992), the Halley data set indicates significantly lower MSA and nss sulfate concentrations, 15 and 50 ng m(-3), respectiveley. The concentrations of both species exhibit a consistent and strong seasonal cycle with maxima from December to March and minima from May to September (from 2 to 4 and from 17 to 50 ng m(-3), for MSA and nss sulfate, respectively). These data, together with radionuclide studies (Pb-210 and Be-10), indicate that the marine biogenic source dominates the sulfur budget of the boundary layer of these regions throughout the year. The contribution of other sources, such as the long-range transported sulfur from continents and to a lesser extent the stratospheric sulfate reservoir, remains weak when averaged over the year. Differences in the seasonal pattern of the two sulfur-containing species, as well as intersite differences in the summer concentrations, are compared to several factors, mainly the spatial and temporal variations of the chlorophyll content of the surface ocean water and the seasonality of the sea ice cover. This permits investigation of the respective influence of marine regions emitting dimethylsulfide located either near the Antarctic continent (south of 60 degrees S) or at more temperate latitudes. A strong correlation is found between the chlorophyll content of the Antarctic ocean and the level of total nss sulfur. Furthermore, nss sulfate and MSA deposition fluxes determined from firn and ice cores extracted at sites located at various distances from the ocean and various altitudes allow assessment of the spatial variation of the marine biogenic sulfur input in Antarctica

    Fracture de la paroi mediale de l'orbite. A propos de 4 observations. [Fracture of the medial wall of the orbit. Apropos of 4 cases]

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    Fractures or the medial wall of the orbit are uncommon and clinical signs are often discreet. This report was focused on isolated fractures of the medial wall of the orbit. Blow-out trauma is usually the cause. In these cases the clinical signs ranged from simple ecchymosis to blindness by haematoma of the orbital cone. Computed tomography is a major tool for diagnosis and making therapeutic indications for these fractures. Treatment depends on the oculomotor involvements as measured by forced duction tests

    Chemical constituents in the air and snow at Dye 3, Greenland—II. Analysis of episodes in April 1989

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    Detailed examination of a two-week period in April 1989 during the Dye 3 Gas and Aerosol Sampling Program shows that episodes of relatively high concentration of certain chemical constituents occur at this time of year. Airborne concentrations of crustal metals such as Al and Ca can exceed 100 ng m−3, while concentrations of SO42− can exceed 1000 ng m−3. Elevated concentrations of MSA, 7Be and 210Pb are also noted. Consideration of synoptic maps and backward air mass trajectories suggests that the episodes are due to transport from a variety of source regions, including Eurasia (transport over the Pole), North America and western Europe. In addition to elevated airborne concentrations, levels of these constituents in surface snow are high during April. However, it is difficult to develop quantitative relationships between concentrations in air and in snow due to the difficulty in measuring airborne concentrations at cloud-level; variations in scavenging by clouds may also be significant. It is concluded that the springtime maxima in airborne concentrations resulting from long-range transport from a variety of source regions are responsible for strong identifiable signals in ice cores and snowpits from this region
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