Cytology of parthenogenesis of five Meloidogyne species

La présente étude a porté sur l'ovogenèse de plusieurs isolats à parthénogenèse méiotique facultative - #Meloidogyne hapla race A, #M. chitwoodi, #M. fallax - et à parthénogenèse améiotique (mitotique) - #M. hapla race B, #M. javanica et l'isolat Xa appartenant à une espèce non identifiée - et ce au moyen d'une technique de coloration fluorescente au Hoechst 33258. En l'absence de fécondation, le nombre de chromosomes somatiques est rétabli par fusion du pronucleus et du second corps polaire chez les isolats de #M. hapla race A, dans tous les autres cas la réduction chromosomique est compensée par la duplication des chromosomes dans le noyau de l'oeuf après la première division. Chez l'une des lignées mono-femelles de l'isolat Xa le développement embryonnaire, génétiquement contrôlé, se produit à l'intérieur de la femelle. Cette étude confirme la grande variabilité des modes de reproduction des espèces de #Meloidogyne ce qui peut expliquer leur succès mondial. Dans un isolat de #M. hapla race A, seuls 12% des oocytes des femelles fécondées contiennent des spermatozoïdes et ce sont les oocytes en prophase 1 - au lieu de la prométaphase 1 - qui sont observés en position postérieure à la spermathèque. (Résumé d'auteur

Thin and thick cloud top height retrieval algorithm with the Infrared Camera and LIDAR of the JEM-EUSO Space Mission

The origin of cosmic rays have remained a mistery for more than a century. JEM-EUSO is a pioneer space-based telescope that will be located at the International Space Station (ISS) and its aim is to detect Ultra High Energy Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) by observing the atmosphere. Unlike ground-based telescopes, JEM-EUSO will observe from upwards, and therefore, for a properly UHECR reconstruction under cloudy conditions, a key element of JEM-EUSO is an Atmospheric Monitoring System (AMS). This AMS consists of a space qualified bi-spectral Infrared Camera, that will provide the cloud coverage and cloud top height in the JEM-EUSO Field of View (FoV) and a LIDAR, that will measure the atmospheric optical depth in the direction it has been shot. In this paper we will explain the effects of clouds for the determination of the UHECR arrival direction. Moreover, since the cloud top height retrieval is crucial to analyze the UHECR and EHECR events under cloudy conditions, the retrieval algorithm that fulfills the technical requierements of the Infrared Camera of JEM-EUSO to reconstruct the cloud top height is presently reported.Comment: 5 pages, 6 figures, Atmohead Conference 201

Vegetation height products between 60° S and 60° N from ICESat GLAS data.

We present new coarse resolution (0.5� ×0.5�)vegetation height and vegetation-cover fraction data sets between 60� S and 60� N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70m in 0.5m intervals for each 0.5�×0.5�. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r =0.33 to r =0.78, decreases the root-mean-square error by a factor 3 to about 6m (RMSE) or 4.5m (68% error distribution) and decreases the bias from 5.7m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r =0.67); the GLAS treecover fraction is compared with the MODIS tree-cover fraction (r =0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface

Real-time leak diagnosis in water distribution systems based on a bank of observers and a genetic algorithm

The main contribution of this paper is to present a novel solution for the leak diagnosis problem in branched pipeline systems considering the availability of pressure head and flow rate sensors on the upstream (unobstructed) side and the downstream (constricted) side. This approach is based on a bank of Kalman filters as state observers designed on the basis of the classical water hammer equations and a related genetic algorithm (GA) which includes a fitness function based on an integral error that helps obtaining a good estimation despite the presence of noise. For solving the leak diagnosis problem, three stages are considered: (a) the leak detection is performed through a mass balance; (b) the region where the leak is occurring is identified by implementing a reduced bank of Kalman filters which localize the leak by sweeping all regions of the branching pipeline through a GA that reduces the computational effort; (c) the leak position is computed through an algebraic equation derived from the water hammer equations in steady-state. To assess this methodology, experimental results are presented by using a test bed built at the Tuxtla Gutiérrez Institute of Technology, Tecnológico Nacional de México (TecNM). The obtained results are then compared with those obtained using a classic extended Kalman filter which is widely used in solving leak diagnosis problems and it is highlighted that the GA approach outperforms the EKF in two cases whereas the EKF is better in one case.Peer ReviewedPostprint (published version

Spatio-temporal variability of mid-size pelagic fishes in the Gulf of Cadiz shelf waters in relation to climatic and environmental drivers

Modeling spatio-temporal patterns of mid-size pelagic fish species (MSPFS) distribution and density is of great interest from the standpoint of both their management and conservation. Herein, temporal changes in the spatial patterns of five MSPFS off the Gulf of Cadiz are analyzed from acoustic surveys data (2007-2017). In particular, we evaluated intra-specific variability over time and space and relate such fluctuations to environmental and climatic drivers aimed to provide support to the implementation of a future ecosystem approach to fisheries management in this region

Spatio-temporal variability of mid-size pelagic fishes in the Gulf of Cadiz shelf waters in relation to climatic and environmental drivers

Understanding spatio-temporal distribution patterns of mid-size pelagic fish species (MSPF) is of great interest from the standpoint of both their management and conservation. MSPF inhabiting in the Gulf of Cadiz (SW Iberian Peninsula, Atlantic Ocean) are relevant because they contribute to a large number of individuals captured by the different fishing métiers operating in the area. So far, information on their spatial distribution and temporal changes remain scarce in the study area despite their implications in their stock discrimination and management. Herein, temporal changes of the distribution patterns of abundance and their response to environmental drivers of five MSPF (Scomber colias, Scomber scombrus, Trachurus trachurus, Trachurus mediterraneus and Trachurus picturatus) off the Gulf of Cadiz (GoC) are analyzed from acoustic surveys data for the period 2007-2017. In particular, we evaluated intra- and inter-specific overlapping over time and space using four spatial indices. The species’ abundance and distribution were estimated and mapped by applying geostatistical techniques taking into account autocorrelation between observations. Furthermore, analyses including environmental variables were tested to explain such spatial fluctuations. The main findings showed a progressive reduction of their distribution area in all species over time except for T. trachurus. The only species overlapping in space and time wasbetween T. picturatus and S. colias. The distribution areas of S. colias and T. mediterraneus were notably reduced and showed northern/southern preferences over the years. The main environmental variables shaping the abundance and distribution of each species were found to be chlorophyll and temperature. Climatic indices such as NAO and AMO affected MSPF by reducing or increasing their spatial distribution. Finally, we discuss implications of our findings to contribute to the implementation of the Marine Strategy Framework Directive in the frame of implementing an effective ecosystem approach to fisheries management in the region

Human retinal Müller cells synthesize collagens of the vitreous and vitreoretinal interface in vitro

Purpose: To investigate the capacity of cultured Muller cells to synthesize collagens, since previous studies indicated that Muller cells could be involved in collagen remodeling at the vitreoretinal border in adult human eyes. Methods: Spontaneously immortalized cultured human Muller cells were analyzed for the presence of mRNA of types I-VII, IX, XI, and XVII collagen by RT-PCR. Furthermore, Muller cells were immunocytochemically stained for light microscopic (LM) evaluation of these collagens and their main characteristics. Finally, cell extracts and culture medium were evaluated by western blot (WB) analysis using anticollagen antibodies. Results: Cultured Muller cells contained mRNA for types I-VII, IX, and XI collagen, but not for type XVII collagen. LM and WB confirmed the intracellular expression of all the above-mentioned collagens with the exception of type XVII. Collagen secretion into the medium was established for types I-VII, IX, and XI collagen. Conclusions: Cultured Muller cells can synthesize internal limiting lamina and vitreous collagens. Possible collagen production by Muller cells could explain and expand on previous in vivo morphological findings in the embryonic and postnatal period and in pathologic conditions