Qualité biologique de l’eau de mer évaluée in situ par le test embryo-larvaire de Crassostrea gigas et Mytilus galloprovincialis = In situ monitoring of sea water quality with the embryo-larval bioassay of Crassostrea gigas and Mytilus galloprovincialis

Embryos and larvae of bivalves are frequently used in marine ecotoxicology for the purpose of assessing seawater quality, because they are very sensitive to pollutants and provide rapid responses. Laboratory studies, however, cannot accurately simulate natural conditions. We conducted bivalve embryo-larval studies in situ at the marina of Arcachon (southwest French Atlantic coast), in order to assess ‘biological quality’ of the water. One experiment conducted in winter 1999 (temperatures of 10 °C) with embryos of the Mediterranean mussel, Mytilus galloprovincialis, has shown that such tests are practicable in winter at low temperatures. This study did not show any deterioration in ‘biological quality’ of the water. Four series of experiments were subsequently performed during summer 2000 (ambient water temperatures of 19 to 22.4 °C) with embryos of the Japanese oyster, Crassostrea gigas. The results show that the ‘sea water biological quality’ deteriorates from the port entrance towards its inner part. To our knowledge, this is the first investigation of the marine environment in which bivalve embryos have been used in situ. They are very suitable for this type of study, because bivalve embryos and larvae are more sensitive to pollutants than the adults, and also because they belong to euryhaline species and the embryos tolerate summer temperatures (both species) as well as winter temperatures (mussels), allowing biomonitoring to be conducted all over the year

Analysis of TerraSAR-X data and their sensitivity to soil surface parameters over bare agricultural fields

International audienceCette recherche a pour objectif de mettre en évidence la contribution des capteurs haute résolution pour une meilleure caractérisation de la surface du sol et pour analyser les effets de la polarisation et de l'angle d'incidence radar. L'objectif de cet article est d'analyser la sensibilité des données haute résolution Terrassar-X sur des sols sans couverture végétale et d'étudier la variabilité spatiale. Les relations entre le coefficient de rétrodiffusion et les paramètres du sol seront étudiés grâce aux images (TerraSAR, Ikonos, SPOT) ainsi que grâce aux mesures de terrain recueillies pendant plusieurs campagnes de terrain en hiver et printemps 2008-2009. Ce travail a été mené sur le bassin de l'Orgeval (France). / Our research aims to show the contribution of high resolution spatial sensors for a better characterization of soil surface, and to analyze polarization effects and radar incidence angle. The objective of this paper is to analyze the sensitivity of very high resolution TerraSAR-X radar data taken over bare soils, and to study the spatial variability. The relationship between backscattering coefficient and soil's parameters (moisture, surface roughness, and texture) will be examined by means of satellite images (TerraSAR, Ikonos, SPOT), as well as ground truth measurements, recorded during several field campaigns in the winter and spring of 2008 and 2009. This study is carried out on Orgeval catchment (France)

Natural Observation of Alcohol Price and Promotions at Bars: Implications for Alcohol Misuse Prevention

Alcohol misuse among young adults remains a primary public health concern given the wide range of short- and longterm physical, social, and societal consequences of the behavior. On-premise drinking establishments, which allow alcohol consumption on site (i.e., bars), are frequent locations for young adult alcohol use. Risks for alcohol misuse within the bar setting are key factors to identify for prevention. Notably, alcohol price and promotions are associated with alcohol consumption among young adults. This study sought to develop and pilot test an observational protocol to assess the alcohol environment at on-premise drinking establishments. Following qualitative exploration of salient risk factors in these settings through focus groups with young adults, an observational tool was adapted and tested in a feasibility study. The refined tool was then pilot tested with two independent data collectors conducting natural observation at 13 establishments in the downtown nightlife district of a small, southeastern city. High interrater reliability was noted. Descriptive summary statistics of bar characteristics demonstrate low alcohol prices with variability across types of alcohol (e.g., beer, wine, and liquor), greater numbers of alcohol promotions inside rather than outside the building, and higher rates of manual versus electronic age verification procedures. Observational assessment of alcohol price and marketing at on-premise drinking establishments as described in this study is needed to inform prevention policy and programs to reduce harms associated with young adult alcohol misuse

Cubic Microcontainers Improve In Situ Colonic Mucoadhesion and Absorption of Amoxicillin in Rats

An increased interest in colonic drug delivery has led to a higher focus on the design of delivery devices targeting this part of the gastrointestinal tract. Microcontainers have previously facilitated an increase in oral bioavailability of drugs. The surface texture and shape of microcontainers have proven to influence the mucoadhesion ex vivo. In the present work, these findings were further investigated using an in situ closed-loop perfusion technique in the rat colon, which allowed for simultaneous evaluation of mucoadhesion of the microcontainers as well as drug absorption. Cylindrical, triangular and cubic microcontainers, with the same exterior surface area, were evaluated based on in vitro release, in situ mucoadhesion and in situ absorption of amoxicillin. Additionally, the mucoadhesion of empty cylindrical microcontainers with and without pillars on the top surface was investigated. From the microscopy analysis of the colon sections after the in situ study, it was evident that a significantly higher percentage of cubic microcontainers than cylindrical microcontainers adhered to the intestinal mucus. Furthermore, the absorption rate constants and blood samples indicated that amoxicillin in cubic microcontainers was absorbed more readily than when cylindrical or triangular microcontainers were dosed. This could be due to a higher degree of mucoadhesion for these particular microcontainers

Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation

The potential use of GPS technology for precise length determination is currently a topic of extensive research. A prior work was dedicated to submillimetric length determination over short baselines and under ideal conditions of data availability and a clear environment. This paper presents a new computation method suited to the less favourable working conditions that are usually encountered in practice. It is based on both robust estimation theory and the use of an ambiguity-free estimation method. As the experimental comparisons with the standard procedure based on least-squares ambiguity determination show, it provides more stable values and permits results to be obtained significant to the submillimetre level with time spans of a few hours.This research is funded by the Spanish Ministry of Science and Innovation (AYA2011-23232).Baselga Moreno, S.; García-Asenjo Villamayor, L.; Garrigues Talens, P. (2014). Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation. Measurement Science and Technology. 25(10):1-6. https://doi.org/10.1088/0957-0233/25/10/105004S162510Altamimi, Z., Collilieux, X., & Métivier, L. (2011). ITRF2008: an improved solution of the international terrestrial reference frame. Journal of Geodesy, 85(8), 457-473. doi:10.1007/s00190-011-0444-4Amiri-Simkooei, A. R., & Tiberius, C. C. J. M. (2006). Assessing receiver noise using GPS short baseline time series. GPS Solutions, 11(1), 21-35. doi:10.1007/s10291-006-0026-8Baire, Q., Bruyninx, C., Legrand, J., Pottiaux, E., Aerts, W., Defraigne, P., … Chevalier, J. M. (2013). Influence of different GPS receiver antenna calibration models on geodetic positioning. GPS Solutions, 18(4), 529-539. doi:10.1007/s10291-013-0349-1Baselga, S. (2007). Global Optimization Solution of Robust Estimation. Journal of Surveying Engineering, 133(3), 123-128. doi:10.1061/(asce)0733-9453(2007)133:3(123)Baselga, S. (2010). Global optimization applied to GPS positioning by ambiguity functions. Measurement Science and Technology, 21(12), 125102. doi:10.1088/0957-0233/21/12/125102Baselga, S. (2014). Ambiguity-Free Method for Fast and Precise GNSS Differential Positioning. Journal of Surveying Engineering, 140(1), 22-27. doi:10.1061/(asce)su.1943-5428.0000111Baselga, S., & García-Asenjo, L. (2008). GNSS Differential Positioning by Robust Estimation. Journal of Surveying Engineering, 134(1), 21-25. doi:10.1061/(asce)0733-9453(2008)134:1(21)Baselga, S., & García-Asenjo, L. (2008). Multipath Mitigation by Global Robust Estimation. Journal of Navigation, 61(3), 385-392. doi:10.1017/s0373463308004803Baselga, S., García-Asenjo, L., & Garrigues, P. (2013). Submillimetric GPS distance measurement over short baselines: case study in inner consistency. Measurement Science and Technology, 24(7), 075001. doi:10.1088/0957-0233/24/7/075001Dow, J. M., Neilan, R. E., & Rizos, C. (2009). The International GNSS Service in a changing landscape of Global Navigation Satellite Systems. Journal of Geodesy, 83(3-4), 191-198. doi:10.1007/s00190-008-0300-3Griffiths, J., & Ray, J. R. (2012). Sub-daily alias and draconitic errors in the IGS orbits. GPS Solutions, 17(3), 413-422. doi:10.1007/s10291-012-0289-1Huber, P. J. (1981). Robust Statistics. Wiley Series in Probability and Statistics. doi:10.1002/0471725250Koivula, H., Häkli, P., Jokela, J., Buga, A., & Putrimas, R. (2011). GPS Metrology: Bringing Traceable Scale to a Local Crustal Deformation GPS Network. International Association of Geodesy Symposia, 105-112. doi:10.1007/978-3-642-20338-1_13Niu, X., Chen, Q., Zhang, Q., Zhang, H., Niu, J., Chen, K., … Liu, J. (2013). Using Allan variance to analyze the error characteristics of GNSS positioning. GPS Solutions, 18(2), 231-242. doi:10.1007/s10291-013-0324-xRay, J., Altamimi, Z., Collilieux, X., & van Dam, T. (2007). Anomalous harmonics in the spectra of GPS position estimates. GPS Solutions, 12(1), 55-64. doi:10.1007/s10291-007-0067-7Snay, R. A., & Soler, T. (2008). Continuously Operating Reference Station (CORS): History, Applications, and Future Enhancements. Journal of Surveying Engineering, 134(4), 95-104. doi:10.1061/(asce)0733-9453(2008)134:4(95)Wieser, A., & Brunner, F. K. (2002). Short Static GPS Sessions: Robust Estimation Results. GPS Solutions, 5(3), 70-79. doi:10.1007/pl00012901Yang, Y. (1999). Robust estimation of geodetic datum transformation. Journal of Geodesy, 73(5), 268-274. doi:10.1007/s001900050243Yang, Y., Song, L., & Xu, T. (2002). Robust estimator for correlated observations based on bifactor equivalent weights. Journal of Geodesy, 76(6-7), 353-358. doi:10.1007/s00190-002-0256-