Resultados preliminares de la campaña marina realizada en el precontinente catalán entre los cañones de la Fonera y Blanes

Los autores hacen un estudio preliminar de la estructura y unidadel sedimentarias deducidas a partir de los perfiles sísmicos y testigos obtenidos en el sector de la platahorma continental comprendida entre los cañones de la Fonera y Blanes (Costa Brava, Gerona), y establece una correlación con los ya estudiadocs del Ampurdán y del Roussillon. Asimismo, se describe una secuencia del Cuaternario reciente a partir de los testigos de gravedad estudiados

A new functional for charge and mass identification in Delta E-E telescopes

We propose a new functional for the charge and mass identification in Delta E-E telescopes. This functional is based on Bethe's formula, allowing safe interpolation or extrapolation in regions with low statistics. When applied to telescopes involving detectors delivering a linear response, as silicon detectors or ionization chambers, a good mass and charge identification is achieved. For other detectors, as caesium-iodide used as a final member of a telescope, a good accuracy is also obtained except in the low residual energy region. A good identification is however recovered if a non-linear energy dependence of the light output is included.Comment: 16 pages, 8 figures, LaTeX2e + EPS figures reduced in size Submitted to Elsevie

"Resultados preliminares de la campaña marina realizada en el precontinente catalán entre los cañones de la Fonera y Blanes"

Los autores hacen un estudio preliminar de la estructura y unidades sedimentarias deducidas a partir de los perfiles sísmicos y testigos obtenidos en el sector de la plataforma continental comprendida entre los cañones de la Fonera y Blanes (Costa Brava, Gerona), y establece una correlación con los ya estudiados del Ampurdán y del Roussillon. Asimismo, se describe una secuencia del Cuaternario reciente a partir de los testigos de gravedad estudiados

Dénombrements directs des bactéries des milieux aquatiques par microscopie en épifluorescence : comparaison entre un système d'analyse d'images automatisé (Mudicam®) et l'observation visuelle

La technique de comptage par microscopie en épitluorescence est la méthode la plus performante pour dénombrer la totalité des bactéries présentes dans les milieux aquatiques. Cependant cette technique est longue, fastidieuse et subjective. Afin d'automatiser et de rendre objectif le dénombrement, le microscope à épifluorescence est couplé à un analyseur d'images. Si les systèmes d'analyse d'images sont utilisés pour les mesures de taille des bactéries aquatiques, très peu d'études font état de comparaison entre les dénombrements par analyse d'image et ceux réalisés de façon traditionnelle. Cet article présente les résultats des dénombrements de souches bactériennes de référence et de bactéries des milieux aquatiques, par la technique de microscopie en épifluorescence des cellules bactériennes marquées au DAPI, réalisés simultanément par observation microscopique visuelle (visuel) et par analyse d'images automatisée (automatique).Le système d'analyse d'images est composé d'une caméra vidéo (Lhesa LH40036) de sensibilité de 510-4 lux, d'une carte de numérisation (512 x 512 pixels, 8 bits, cyclope v 2.32, Digital vision) d'un micro-ordinateur 80-386 et d'un logiciel de dénombrement (Mudicam®. EAU). Le système est couplé à un microscope en épilluorescence Olympus BH2.Les dénombrements ont été réalisés d'une part sur des suspensions de souches bactériennes de référence (n = 30) à différents états physiologiques et sur des échantillons d'eaux (n = 50) d'origines diverses (fleuve, eaux saumâtre, marine et résiduaire). La comparaison des deux méthodes est réalisée par un modèle de régression linéaire et une analyse de variance. Les tests statistiques associés permettent de conclure à une bonne concordance entre les deux méthodes. A partir de l'ensemble des dénombrements réalisés, 18 d'entre eux pris au hasard ont été dénombrés de façon manuelle par deux opérateurs et par le système d'analyse d'image. Il apparaît que les différences de comptage les plus élevées correspondent aux dénombrements effectués par chacun des deux opérateurs. Ceci met en évidence que non seulement le système d'analyse d'image permet une quantification rapide des abondances bactériennes, mais en outre il supprime la subjectivité de l'opérateur tout en réalisant des dénombrements aussi précis.Direct counting by epifluorescence microscopy is the best method available to determine total counts of aquatic bacteria. However, microscopic observation is tedious and time-consuming. A more rapid and certainly less subjective way of counting bacteria is to combine epifluorescence microscopy with an image analysis system. Surprisingly, although image analysis is now a relatively common method to measure the size of aquatic bacteria, very few studies have been devoted to the validation of total counts by image-analysis systems. In this paper, we present data on simultaneous determination of total counts of 4'6-diamidino-2-phenylindole (DAPI) stained bacteria by visual means and by image-analysed (Mudicam® system) epifluorescence microscopy methods.The Olympus microscope BH2 is equipped for epifluorescence with a 100 W Hg lamp and a 100x oil immersion objective (Apo UVFL 160/1.3). The image analysis system consists et a high performance (5 x 10-4 lux) video camera (Lhesa LH40036) and an image processor which digitalizes the video image in a grey scale extending from 0 (black) to 255 (white) into a binary image with 512 x 512 pixels (8 bit, cyclope v 2.32, Digital Vision), and image analysis software (MUDICAM®. EAU). The samples were stained with DAPI (final concentration 2.5 µg/ml) and filtered through polycarbonate inters (0.22µm, Nuclepore Corporation). The surface area of the video image is 76 x 111 µm2.The analysed samples come from culture collections of different bacterial strains (n = 30) submitted to different conditions and incubation times to obtain various physiological states (Table 1). The nature water samples were collected from several aquatic ecosystems : Rhône river, Mediterranean sea, Thau lagoon and Montpellier sewage waters (n = 50). The bacterial abundances ranged from 105 to 108 cells/ml and the size range of the cells varied from 0.63 to 17 µm2. Comparisons between the image analysis and visual counts were made on the basic of thirty fields per filter. The image analysis counts are based on a two step procedure. The video image of each microscopie field is first numerised and stored on a hard disk (153 Mo). When all the fields have been stored, the digitized images are submitted to an automatic thresholding which allows background substraction. Automatic counting of bacterial cells is then performed on the basis of object specifications defined by the operator. These specifications concern the minima and maxima values of the area (expressed in pixel numbers) and the fluorescence (expressed in gray levels) of the objects. The MUDICAM®EAU software also provides the mean number of cells per millilitre and the associated variance.Average concentrations and confidence limits are shown in Table 2 for bacterial collection strain cultures and in Table 3 for water samples. When we compared visual and image analysis counts by- linear regression, the ability of the image analysis system to enumerate bacterial cells was clearly demonstrated. With bacterial culture (Fig. 2) and with water samples (Fig. 3), the coefficients of correlation were respectively r = 0.997 and r = 0.996 (p = 0.0001). The slopes of the models are not significantly different from unity and the Y-intercepts are not different from zero. Moreover we have compared the total visual counts of two experimenters and the image-analysed counts on eighteen random samples (Table 4). The variance analysis shows that there is no difference between the three methods, with mean value of 6.09, 6.08 and 6.11 for the image-analysed method, experimenter n° 1 and experimenter n° 2, respectively. While non significant, the greatest difference in counts was obtained between the two experimenters.If may be concluded that the image analyser tested for total counts by epifluorescence microscopy is a precise and rapid procedure for the determination of total bacterial counts. This method may be standardized and its automation allows the analysis of many samples, an important advantage in ecological studies. Storage of the samples also allows one to treat a posteriori some complementary aspects of the total count, such as the double staining of bacteria. The image analyser tested is appropriate for bacterial ecology studies which require epifluorescence microscopy

Pre-failure behaviour of an unstable limestone cliff from displacement and seismic data

We monitored the displacement and seismic activity of an unstable vertical rock slice in a natural limestone cliff of the southeast Vercors massif, southeast France, during the months preceding its collapse. Displacement measurements showed an average acceleration of the movement of its top, with clear increases in the displacement velocity and in the discrete seismic event production rate during periods where temperature falls, with more activity when rainfall or frost occurs. Crises of discrete seismic events produce high amplitudes in periodograms, but do not change the high frequency base noise level rate. We infer that these crises express the critical crack growth induced by water weakening (from water vapor condensation or rain) of the rock strength rather than to a rapid change in applied stresses. Seismic noise analysis showed a steady increase in the high frequency base noise level and the emergence of spectral modes in the signal recorded by the sensor installed on the unstable rock slice during the weeks preceding the collapse. High frequency seismic noise base level seems to represent subcritical crack growth. It is a smooth and robust parameter whose variations are related to generalized changes in the rupture process. Drop of the seismic noise amplitude was concomitant with the emergence of spectral modes – that are compatible with high-order eigenmodes of the unstable rock slice – during the later stages of its instability. Seismic noise analysis, especially high frequency base noise level analysis may complement that of inverse displacement velocity in early-warning approaches when strong displacement fluctuations occur

Evaluation of spiking methods for the preparation of a proficiency testing material in cereal matrices: Measurements of 131I, 134Cs and 137Cs in cereal matrices

Among many radionuclides released to the environment during a radiological emergency 131I, 134Cs and 137Cs are usually the most abundant ones. They are transferred to air, water and soil and from those media readily relocated to plants, including those intended for human consumption and for animal feed. Ensuring safe feed is an important component of the efforts to reduce and prevent food safety hazards, especially now, as consumers are increasingly aware of food safety issues and their linkage to animal production, including feeding practices. Therefore it is of utmost importance to ensure that the results of measurements of those three radionuclides delivered by the monitoring laboratories across the EU are reliable in order to guarantee a high degree of feed and food safety. It would be also beneficial to establish a standardised method of analysis for those radionuclides, which requires intra- and interlaboratory tests. In order to conduct such tests a reliable reference material is needed. Since one of the radionuclides (131I) is very short-lived (T1/2 = 8.0233 ± 0.0019 days) a spiking method for preparing test samples is necessary. Therefore procedures for spiking of powder were tested. Two methods of material preparation were tested – spiking a bulk sample of powder and individual spiking, where radioactive solution was introduced directly into containers in which samples were being measured. Both methods provided satisfying results. The bulk spiking method was proven to give homogenous samples, which was confirmed by one way analysis of variance (ANOVA) test. In the second method the relative deviation between the amount of the activity added and the calculated activity values was low and lower than the values of uncertainty calculated for the measured activity values. Therefore it can be stated that the closeness of agreement between the activity added to the sample and activity measured was satisfactory. This proves that these samples may be used as a reference material for the method validation and for the next proficiency test planned by the JRC Geel.JRC.G.2-Standards for Nuclear Safety, Security and Safeguar

El sistema deposicional del Golfo de León

El sistema deposicional del Golfo de León presenta una plataforma  constituida por varios prismas epicontinentales, un talud y unascenso continental entallados por numerosos cañones, y dos cuerpos deposicionales profundos de gran importancia: el abanico del Ródano y el «Acúmulo de los Cañones Pirenaicos)). Las evaporitas messinienses han jugado un papel determinante en la evolución morfo-sedimentaria de este sistema durante el Plio-Cuaternario

Development of Particulate Matter Certified Reference Materials (PM10 CRMs) - Final Report

The present report summarises the work carried out within the feasibility study devoted to the development of particulate matter certified reference materials (PM10 CRMs) at the RM Unit of IRMM. At present there is no suitable PM10 CRM certified for elements and/or PAHs. Therefore, this project was aimed at developing a CRM, which will play an active tool in the implementation of the Air Quality Framework Directive and its 1st and 4th Daughter Directives. In order to establish the target characteristics for the future PM10 CRMs, a meeting with experts in the field of air quality was organised. This report includes decisions made during that meeting.JRC.D.2-Reference material

Fine structure of the 0.7 MeV resonance in the 230Th neutron--induced cross section

The fine structure of the 0.7 MeV resonance in the 230Th neutron-induced cross section is investigated within the hybrid model. A very good agreement with experimental data is obtained. It is suggested that fine structure of the cross section quantify the changes of the intrinsic states of the nucleus during the disintegration process.Comment: 7 pages, 5 figure