64 research outputs found
Cartographie automatisée des zones à hauts risques naturels par superposition de données multivariées : exemple de la commune de Seillans (Var)
Mémoire HS n° 15 - Géologie Alpine Risques naturels dans le Sud-est de la France - Colloque Association des Géologues du Sud-est - Avignon, 19 et 20 octobre 1989Dans le cadre d'une étude financée par l'EPR PACA, nous avons développé une méthode de cartographie des zones soumises à des mouvements du sol, à l'aide de moyens infonnatiques. Nous avons appliqué cette méthode à la commune de Seillans afin d'intégrer cette carte des risques dans le plan d'occupation des sols. Parmi les phénomènes naturels qui contraignent l'utilisation du sol, nous n'avons pris en compte que le phénomène glissement de terrain : il n'est en effet pas encore possible par les méthodes employées de mettre en évidence les zones soumises à des phénomènes de dissolution; nous avons également laissé de coté le risque lié à l'instabilité des falaises et des chutes de blocs. Pour réaliser cette cartographie des zones soumises à des mouvements de sol, nous avons retenu trois facteurs: - nature lithologique des terrains affleurant, - pente topographique et sa valeur en pourcentage - hydrologi
In vitro effects of tyre debris organic extract on the kinetic and morphologic traits of rabbit spermatozoa
[EN] The present study aims at evaluating the effects of the organic extract of tyre debris (TDOE) from tyre wear on the kinetic and morphologic features of rabbit spermatozoa. Rabbit sperm were incubated for 4 h with 0, 5, 10, 50 and 75 Âżg/mL of TDOE. Sperm motility was evaluated by computer-assisted semen analysis. Phosphatidilcholine (PS) externalization (apoptosis) and plasma membrane breakage (necrosis) were assessed using the annexinV/propidium iodide assay. The sperm ultrastructure was observed by scanning (SEM) and transmission electron microscopy (TEM). A relevant decrease in the motility rate, PS externalization, and in plasma membrane breakage of spermatozoa were observed after incubation with TDOE at concentrations higher than 50 Âżg/mL. The most frequent ultrastructural anomalies detected in the analysed specimens were: plasma and/or acrosomal membrane breakage, swollen and disorganized mitochondria, and altered axonemal patterns. Taken together, these results suggest that the organic extract of tyre debris can be toxic to rabbit spermatozoa Âż affecting their movement and structural integrity Âż when present in seminal plasma at a concentrations higher than 50 Âżg/mL. Although rabbit sperm has been proven to be a suitable model for testing the in vitro effects of many chemical compounds, including TDOE, the obtained results must be considered preliminary and cannot be extrapolated yet to the in vivo outcomes because of scanty data. The results encourage, however, further research in this field.Supported by the PROLIFE Flagship project, city of Milan, ItalyMoretti, E.; Dal Bosco, A.; Mourvaki, E.; Cardinali, R.; Collodel, G.; Geminiani, M.; Cetta, F.... (2009). In vitro effects of tyre debris organic extract on the kinetic and morphologic traits of rabbit spermatozoa. World Rabbit Science. 17(4):213-220. doi:10.4995/wrs.2009.64621322017
Late Aptian paleoclimate reconstruction of the Brazilian equatorial margin: inferences from palynology
This study conducted high-resolution paleoclimatic analyses based on the
identification of palynological groups of late Aptian age (biozone
Sergipea veriverrucata) in the Bragança and Codó formations within the Bragança–Viseu,
SĂŁo LuĂs, and ParnaĂba basins. The analysis comprised 40
palynological samples, with 200 palynomorphs per slide counted when
possible. Bioclimatic analysis was mainly supported by the identification of
botanical affinities, and ecological and climatic parameters such as the
wet/arid trend (Fs/X), Shannon–Wiener diversity, and indicator species
analysis (IndVal) were used. Statistical analyses such as principal
component and cluster analyses were employed to support the paleoclimatic
interpretations. The study recognized 69 genera distributed among the main
groups of living plants, including bryophytes, ferns, lycophytes,
gymnosperms, and angiosperms. It was possible to attribute botanical
affinity in 94.2 % of the taxa, and nine genera occurred in all sections
studied: Afropollis, Araucariacites, Callialasporites, Cicatricosisporites, Classopollis, Cyathidites, Deltoidospora, Equisetosporites, and Verrucosisporites, with Classopollis being the most abundant. The
stratigraphic distribution of the bioclimatic groups (hydrophytes,
hygrophytes, lowland tropical flora, upland flora, and xerophytes) allowed
for the identification of climatic phases: pre-evaporitic, evaporitic, and
post-evaporitic. In the pre-evaporitic phase, the most significant
abundances were between the hygrophytes and upland flora, indicating a
certain level of humidity. Xerophytes were the most abundant in all phases,
with a conspicuous increase in the evaporitic phase, reflecting an increase
in aridity. In the post-evaporitic phase, there was a significant increase
in the upland flora with the return of wetter conditions. This study
confirmed an increasing humidity trend in the analyzed sections, probably
owing to the influence of the Intertropical Convergence Zone that was already
operating during the late Aptian.</p
Current situation on data exchange in agriculture in the EU27 & Switzerland
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The Southeast France basin during Late Cretaceous times: The spatiotemporal link between Pyrenean collision and Alpine subduction,
International audienceWe present and discuss the Late Cretaceous evolution of the Southeast France Basin (SEFB) owing to the Pyrenean and Alpine belts. The available geological data (isopachs maps, boreholes and field data) were integrated in 3D GeoModeller software to build a 3D model of the geometry of the Cenomanian to Campanian sedimentary series of the Late Cretaceous period. Maps, 3D block diagrams and cross-sections extracted from the 3D model reveal a significant eastward marine regression during the Late Cretaceous with an average velocity of 0.5 to 1 cm per year. According to the location of the Late Cretaceous depocenters, two sub-basins are recognized in the SEFB and correspond to "en-Ă©chelon" synclines filled by syn-buckling sediments. These events are related to the sub-meridian "Pyrenean-Provence" crustal shortening. During Campanian time, the deepening and the tilting of the SEFB are interpreted as a consequence of the subduction of the Alpine Tethys. The Late Cretaceous SEFB is the prolongation on the European foreland of the Alpine subduction trench
Sperm ultrastructure and meiotic segregation in a group of patients with chronic hepatitis B and C
Little is known about the effect of chronic hepatitis B and hepatitis C on sperm quality. In this study, we analysed sperm quality from selected patients with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections. Semen samples were examined by light and transmission electron microscopy (TEM). TEM data were elaborated with a mathematical formula able to indicate a fertility index and the presence of the three main sperm pathologies: apoptosis, immaturity and necrosis. Meiotic chromosome segregation was investigated by fluorescence in situ hybridisation carried out on sperm nuclei, using probes for chromosomes 18, X and Y. Despite normal sperm concentration, we observed reduced motility. TEM analysis highlighted that 35.7% of patients showed generally good semen quality. However, significantly higher values of apoptosis and necrosis, compared with controls, were observed, demonstrating spermatogenetic alterations. Regarding meiotic segregation, we found an incidence of disomies similar to that observed in control samples, whereas diploidy resulted higher in HCV patients, without reaching statistical significance. In conclusion, sperm quality in the studied group was not impaired; however, apoptosis and necrosis resulted out of normal range and the fertility index was significantly lower in HCV- and HBV-infected patients versus controls. © 2008 The Authors
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