Search

One of the commonly used non-parametric morphometric statistics for galaxy profiles and images is the asymmetry statistic. With an eye to current and upcoming large neutral hydrogen (HI) surveys, we develop a 3D version of the asymmetry statistic that can be applied to datacubes. This statistic is more resilient to variations due to the observed geometry than 1D asymmetry measures, and can be successfully applied to lower spatial resolutions (3-4 beams across the galaxy major axis) than the 2D statistic. We have also modified the asymmetry definition from an `absolute difference' version to a `squared difference' version that removes much of the bias due to noise contributions for low signal-to-noise observations. Using a suite of mock asymmetric cubes we show that the background-corrected, squared difference 3D asymmetry statistic can be applied to many marginally resolved galaxies in large wide-area HI surveys such as WALLABY on the Australian SKA Pathfinder (ASKAP)., Comment: 14 pages, Accepted to MNRAS

Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) provides high-quality space data on stellar photometry to the astronomical community. We present the results of an analysis of TESS photometric data for known slowly rotating magnetic chemically peculiar (mCP) stars. In general, mCP stars show an inhomogeneous distribution of elements in their stellar atmospheres that leads to spectroscopic (line profile) and photometric (light curve) variations over the rotation period. In the frame of the oblique magnetic rotator (OMR) model, patches of enhanced chemical abundance on the stellar surface reveal the frequency of stellar rotation. Using this approach, we have compiled a list of slowly rotating mCP stars with rotation periods longer than two days from the analysis of the photometric data provided by TESS for the first eight sectors of observations. Slowly rotating mCP stars usually possess a hydrodynamically stable stellar atmosphere where a magnetic field can amplify the process of atomic diffusion and leads to the horizontal and vertical stratification of chemical abundances., Comment: 5 pages, 1 figure, PTA Proceedings

It was confirmed in the Brereton report that there’s ‘credible information’ to substantiate the unlawful killing of 39 people by Australian special forces personnel in Afghanistan. These shocking allegations led Prime Minister Scott Morrison to announce last week that a special investigator’s office will be established to assist the Australian Federal Police to investigate these alleged crimes. The information contained in the Brereton report will now serve as a guide for the special investigator’s office, which will focus on gathering evidence that will be admissible in criminal prosecutions.

Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) provides high-quality space data on stellar photometry to the astronomical community. We present the results of an analysis of TESS photometric data for known slowly rotating magnetic chemically peculiar (mCP) stars. In general, mCP stars show an inhomogeneous distribution of elements in their stellar atmospheres that leads to spectroscopic (line profile) and photometric (light curve) variations over the rotation period. In the frame of the oblique magnetic rotator (OMR) model, patches of enhanced chemical abundance on the stellar surface reveal the frequency of stellar rotation. Using this approach, we have compiled a list of slowly rotating mCP stars with rotation periods longer than two days from the analysis of the photometric data provided by TESS for the first eight sectors of observations. Slowly rotating mCP stars usually possess a hydrodynamically stable stellar atmosphere where a magnetic field can amplify the process of atomic diffusion and leads to the horizontal and vertical stratification of chemical abundances., Comment: 5 pages, 1 figure, PTA Proceedings

UNAFLOW (UNsteady Aerodynamics for Floating Wind) is a joint EU-IRPWIND founded experiment on wind turbine rotor unsteady aerodynamics. It brings together four different academic contributors: Energy research Centre of the Netherlands (ECN), DTU Wind Energy, University of Stuttgart (USTUTT) and Politecnico di Milano (PoliMi) sharing knowledge both in numerical modelling and in experimental tests design, allowing direct numerical and experimental comparison. The experimental tests carried out for UNAFLOW are of the same type of the ones carried out during the ongoing EU H2020 project LIFES50+ [1], regarding both the unsteady behaviour of the 2d blade section and the entire turbine rotor, although with improved setup and wider test matrix. The project partners are already currently jointly collaborating in the AVATAR project [2], developing and validating numerical models of different accuracy level. The numerical models used in the UNALFOW project range from engineering tool (eg. BEM) to high fidelity CFD methods. Numerical simulations are used both in the design of experiment phase and in the results analysis allowing for an in depth understanding of the experimental findings through advanced modelling approach. The UNAFLOW project, together with a new understanding of the unsteady behaviour of the turbine rotor aerodynamics, will provide also an open database to be shared among the scientific community for future analysis and new models validation.

Contains fulltext : 117211.pdf (publisher's version ) (Open Access)

Contains fulltext : 117211.pdf (publisher's version ) (Open Access)

Contains fulltext : 117211.pdf (publisher's version ) (Open Access)

Contains fulltext : 117211.pdf (publisher's version ) (Open Access)

In this paper measurements are presented of pi(+/-), K-+/-, p, and (p) over bar production at midrapidity (vertical bar y vertical bar < 0.5), in Pb-Pb collisions at root s(NN) = 2.76 TeV as a function of centrality. The measurement covers the transverse-momentum (p(T)) range from 100, 200, and 300 MeV/c up to 3, 3, and 4.6 GeV/c for pi, K, and p, respectively. The measured p(T) distributions and yields are compared to expectations based on hydrodynamic, thermal and recombination models. The spectral shapes of central collisions show a stronger radial flow than measured at lower energies, which can be described in hydrodynamic models. In peripheral collisions, the p(T) distributions are not well reproduced by hydrodynamic models. Ratios of integrated particle yields are found to be nearly independent of centrality. The yield of protons normalized to pions is a factor similar to 1.5 lower than the expectation from thermal models.

Contains fulltext : 91815.pdf (publisher's version ) (Open Access)

Contains fulltext : 91815.pdf (publisher's version ) (Open Access)

No abstract available

Current developments of magnetic data storage and processing technologies make highly desirable to control fast and reproducible magnetic-domain-wall motion in narrow magnetic tracks, using either magnetic field or electrical current. For this purpose, nanotracks defined in ultrathin magnetic films with out-of-plane anisotropy seem to be particularly interesting. However, in most of the out-of-plane metallic nanosystems which were studied up to now, domain-wall pinning was shown to still play a predominant role, which resulted in low domain-wall velocities, as compared to the ones observed in plain magnetic films [1]. Using magneto-optical microscopy, we show that in an etched Pt/Co/Pt nanotrack with out-of-plane anisotropy, where pinning has been artificially reduced by He+-irradiation [2], weakly-pinned domain-walls can propagate as fast and under magnetic fields as low as in the corresponding plain irradiated film (Fig. 1) [3]. Moreover, when magnetic-field and electrical-current pulses are simultaneously applied to the track, a considerably faster magnetization reversal is observed, which is due to a Joule-heating-induced thermomagnetic effect [3]. This work was partially supported by the EU-“Research Infrastructures Transnational Access” program “Center for Application of Ion Beams in Materials Research” under contract no. 025646, and by the French ANR-07-NANO-034 “Dynawall” project. * now at Radboud University Nijmegen, Institute for Molecules and Materials, Netherlands [1] F. Cayssol et al., Phys. Rev. Lett. 92, 107202 (2004). [2] C. Chappert et al., Science 280, 1919 (1998). [3] M. Cormier et al., submitted (2011).

Current developments of magnetic data storage and processing technologies make highly desirable to control fast and reproducible magnetic-domain-wall motion in narrow magnetic tracks, using either magnetic field or electrical current. For this purpose, nanotracks defined in ultrathin magnetic films with out-of-plane anisotropy seem to be particularly interesting. However, in most of the out-of-plane metallic nanosystems which were studied up to now, domain-wall pinning was shown to still play a predominant role, which resulted in low domain-wall velocities, as compared to the ones observed in plain magnetic films [1]. Using magneto-optical microscopy, we show that in an etched Pt/Co/Pt nanotrack with out-of-plane anisotropy, where pinning has been artificially reduced by He+-irradiation [2], weakly-pinned domain-walls can propagate as fast and under magnetic fields as low as in the corresponding plain irradiated film (Fig. 1) [3]. Moreover, when magnetic-field and electrical-current pulses are simultaneously applied to the track, a considerably faster magnetization reversal is observed, which is due to a Joule-heating-induced thermomagnetic effect [3]. This work was partially supported by the EU-“Research Infrastructures Transnational Access” program “Center for Application of Ion Beams in Materials Research” under contract no. 025646, and by the French ANR-07-NANO-034 “Dynawall” project. * now at Radboud University Nijmegen, Institute for Molecules and Materials, Netherlands [1] F. Cayssol et al., Phys. Rev. Lett. 92, 107202 (2004). [2] C. Chappert et al., Science 280, 1919 (1998). [3] M. Cormier et al., submitted (2011).

Current developments of magnetic data storage and processing technologies make highly desirable to control fast and reproducible magnetic-domain-wall motion in narrow magnetic tracks, using either magnetic field or electrical current. For this purpose, nanotracks defined in ultrathin magnetic films with out-of-plane anisotropy seem to be particularly interesting. However, in most of the out-of-plane metallic nanosystems which were studied up to now, domain-wall pinning was shown to still play a predominant role, which resulted in low domain-wall velocities, as compared to the ones observed in plain magnetic films [1]. Using magneto-optical microscopy, we show that in an etched Pt/Co/Pt nanotrack with out-of-plane anisotropy, where pinning has been artificially reduced by He+-irradiation [2], weakly-pinned domain-walls can propagate as fast and under magnetic fields as low as in the corresponding plain irradiated film (Fig. 1) [3]. Moreover, when magnetic-field and electrical-current pulses are simultaneously applied to the track, a considerably faster magnetization reversal is observed, which is due to a Joule-heating-induced thermomagnetic effect [3]. This work was partially supported by the EU-“Research Infrastructures Transnational Access” program “Center for Application of Ion Beams in Materials Research” under contract no. 025646, and by the French ANR-07-NANO-034 “Dynawall” project. * now at Radboud University Nijmegen, Institute for Molecules and Materials, Netherlands [1] F. Cayssol et al., Phys. Rev. Lett. 92, 107202 (2004). [2] C. Chappert et al., Science 280, 1919 (1998). [3] M. Cormier et al., submitted (2011).

The Streamside Tailings Operable Unit in the Silver Bow Creek/Butte Superfund site in Montana requires removal and disposal of mine and milling wastes in relocation repositories. The Record of Decision (ROD) for the site requires that mine wastes be amended with lime and revegetated, and that the repositories be sited in a protective location, possibly near Silver Creek. If the near-stream location is not sufficiently protective of human health and the environment, then the ROD provides for locating the repositories off-site in more protective conditions. A comparison was carried out of near- and off-stream settings and an assessment made of which types of design elements could be incorporated to raise the level of protectiveness to the environment. Alternatives, and associated costs, considered included different liner systems, leachate generation rates, synthetic leachate characteristics, soil attenuation characteristics and estimated contaminant concentrations in groundwater., The Streamside Tailings Operable Unit in the Silver Bow Creek/Butte Superfund site in Montana requires removal and disposal of mine and milling wastes in relocation repositories. The Record of Decision (ROD) for the site requires that mine wastes be amended with lime and revegetated, and that the repositories be sited in a protective location, possibly near Silver Creek. If the near-stream location is not sufficiently protective of human health and the environment, then the ROD provides for locating the repositories off-site in more protective conditions. A comparison was carried out of near- and off-stream settings and an assessment made of which types of design elements could be incorporated to raise the level of protectiveness to the environment. Alternatives, and associated costs, considered included different liner systems, leachate generation rates, synthetic leachate characteristics, soil attenuation characteristics and estimated contaminant concentrations in groundwater.

Rotavirus double-stranded RNA was detected directly in sewage treatment plant samples over a 1-year period by reverse transcription followed by PCR amplification of the VP7 gene and Southern blot hybridization. The presence of naturally occurring rotaviruses was demonstrated in 42% of raw sewage samples and in 67% of treated effluent samples, Amplified viral sequences were analyzed bg restriction enzymes. Ten different restriction profiles were characterized, most of which were found in treated effluent samples. A mixture of restriction profiles was observed in 75% of contaminated effluent samples, The profiles were compared with those obtained from human rotavirus isolates involved in infections in children from the same area (six different profiles were detected), Five identical viral sequences were detected in both environmental and clinical samples, Restriction profiles sere also compared io profiles from known genomic sequences of human and animal viruses. Both human and animal origins of rotavirus contamination of water seemed likely.

Rotavirus double-stranded RNA was detected directly in sewage treatment plant samples over a 1-year period by reverse transcription followed by PCR amplification of the VP7 gene and Southern blot hybridization. The presence of naturally occurring rotaviruses was demonstrated in 42% of raw sewage samples and in 67% of treated effluent samples, Amplified viral sequences were analyzed bg restriction enzymes. Ten different restriction profiles were characterized, most of which were found in treated effluent samples. A mixture of restriction profiles was observed in 75% of contaminated effluent samples, The profiles were compared with those obtained from human rotavirus isolates involved in infections in children from the same area (six different profiles were detected), Five identical viral sequences were detected in both environmental and clinical samples, Restriction profiles sere also compared io profiles from known genomic sequences of human and animal viruses. Both human and animal origins of rotavirus contamination of water seemed likely.

Rotavirus double-stranded RNA was detected directly in sewage treatment plant samples over a 1-year period by reverse transcription followed by PCR amplification of the VP7 gene and Southern blot hybridization. The presence of naturally occurring rotaviruses was demonstrated in 42% of raw sewage samples and in 67% of treated effluent samples, Amplified viral sequences were analyzed bg restriction enzymes. Ten different restriction profiles were characterized, most of which were found in treated effluent samples. A mixture of restriction profiles was observed in 75% of contaminated effluent samples, The profiles were compared with those obtained from human rotavirus isolates involved in infections in children from the same area (six different profiles were detected), Five identical viral sequences were detected in both environmental and clinical samples, Restriction profiles sere also compared io profiles from known genomic sequences of human and animal viruses. Both human and animal origins of rotavirus contamination of water seemed likely.

Rotavirus double-stranded RNA was detected directly in sewage treatment plant samples over a 1-year period by reverse transcription followed by PCR amplification of the VP7 gene and Southern blot hybridization. The presence of naturally occurring rotaviruses was demonstrated in 42% of raw sewage samples and in 67% of treated effluent samples, Amplified viral sequences were analyzed bg restriction enzymes. Ten different restriction profiles were characterized, most of which were found in treated effluent samples. A mixture of restriction profiles was observed in 75% of contaminated effluent samples, The profiles were compared with those obtained from human rotavirus isolates involved in infections in children from the same area (six different profiles were detected), Five identical viral sequences were detected in both environmental and clinical samples, Restriction profiles sere also compared io profiles from known genomic sequences of human and animal viruses. Both human and animal origins of rotavirus contamination of water seemed likely.

La recherche des coliformes dans les milieux extérieurs, en particulier dans l'eau, par les techniques traditionnelles nécessite en premier, la filtration d'une quantité suffisante d'eau, suivie de la culture des filtres sur un milieu sélectif. Ceci permet d'identifier les bactéries utilisant le lactose en tant que seule source de carbone (Greenberg, 1985). Les Escherichia coli entérotoxigènes sont ensuite recherchés par les tests de détection de l'entérotoxine LT effectués sur le surnageant de la culture bactérienne. Ces tests sont basés sur l'activités biologique (culture sur cellules vero et Y1) ou immunologique (latex, GM1-ELISA, Biken, ...) et/ou radio-immunologique (Sack and Sack, 1975 ; Honda et al., 1981 ; Ito et al., 1983 ; Ristaino et al., 1983). Ces méthodes souvent coûteuses manquent de précision pour détecter spécifiquement une sorte de bactérie dans une grande quantité d'eau. Dans un échantillon donné d'environnement, il est possible de dénombrer un certain nombre de bactéries utilisant le lactose, mais, la production de toxine LT ne peut être associée qu'à la présence d'un petit nombre d'E.coli entérotoxinogènes.

Peu d'études ont été réalisées sur la distribution, le transfert et les fonctions des plasmides existants dans les bactéries de l'environnement (Smith, 1970 ; Glasman et al., 1981 ; Hada et Sizemore, 1981). Hada et Sizemore (1981) en faisant une étude comparative sur le nombre des plasmides contenus dans 440 isolements de Vihrio marins du Golfe de Mexico ont démontré que l'incidence des plasmides est plus importante dans des isolements marins des sites pollués, que dans des isolements marins de sites non contaminés. Par contre, Burton et al. en 1982, en travaillant dans une rivière de South Wales, n'ont pas trouvé de différence significative entre les sites pollués et ceux non pollués sur le pourcentage total des isolements contenant des plasmides ainsi que sur l'incidence des plasmides des souches non "Pseudomonas -like" provenant des mêmes endroits. La majorité (86%) des plasmides détectés ont une masse moléculaire entre 35 et 312 Md. Baya et al., 1986, ont fait une étude comparative entre 4 zones : 1) des eaux provenant d'une station qui reçoit surtout des déchets chimiques 2) des eaux proches de la station 3) des eaux océaniques contaminées par des rejets domestiques 4) des eaux propres utilisées comme contrôle. Les résultats obtenus montrent que le nombre de bandes plasmidiques par souche dans les différentes zones diminue dès la zone 1 vers la zone 4. L'objectif de notre travail est d'examiner dans un premier temps, le contenu plasmidique des souches d'E.coli venant des eaux brutes, eaux épurées et des eaux de la sortie de la station d'épuration de Morlaix. Et dans un deuxième temps, étudier l'évolution de ces plasmides dans l'environnement pendant différents temps de séjour.

Illnesses due to marine bivalvia consumption are mostly associated with viruses as causative agents. In more than the half of cases, this agent remains unidentifies, nevertheless. So far as bacteria are concerned, Salmonella are found firstly. Campylobacters represent a major cause of gastrointestinal disease, with Salmonella, among humans. Whether campylobacteriosis may be acquired from shellfishes remains unclear. We undertook to comparatively appreciate the survival of Campylobacter jejuni/coli and Salmonella typhimurium in seawater and contaminated mussels. Bacterial enumerations where performes using microbial cultures and specific (with immunofluorescence) direct viable counts (of substrate responsive bacteria). During laboratory contamination experiments, C. jejuni/coli and S. typhimurium are aforded together with unicellular microalgae Tetraselmis suecica. Mussels incorporate efficiently these microorganisms into their digestive tract (up 100 to 500 folds the concentration of contamination tank). In the gut of contaminated mussels, stored dry at 16 degree C, the number of culturable Salmonella remains constant after one week whereas C. jejuni persists in constant number of viable cells but exhibits a 10000 fold decrease of culturable bacteria. In seawater, Campylobacter survive poorly, compared with Salmonella: from comparable initial densities, the difference may reach a 106 factor after one week. The occurrence of mussel contamination with Salmonella is customary in polluted seawater: it should remain neglectible with Campylobacter. The cells of C. coli which survived after a 6 days stay into contaminated seawater and mussels maintained intacts virulence factors: mobility and adherence to cultured HeLa cells. This is at least true for bacteria remaining culturable, and questionable for viable non culturable cells. On the whole, shellfish born diseases due to Campylobacter should actually be possible (Griffin et al., 1983). This whould nevertheless represen

Peu d'études ont été réalisées sur la distribution, le transfert et les fonctions des plasmides existants dans les bactéries de l'environnement (Smith, 1970 ; Glasman et al., 1981 ; Hada et Sizemore, 1981). Hada et Sizemore (1981) en faisant une étude comparative sur le nombre des plasmides contenus dans 440 isolements de Vihrio marins du Golfe de Mexico ont démontré que l'incidence des plasmides est plus importante dans des isolements marins des sites pollués, que dans des isolements marins de sites non contaminés. Par contre, Burton et al. en 1982, en travaillant dans une rivière de South Wales, n'ont pas trouvé de différence significative entre les sites pollués et ceux non pollués sur le pourcentage total des isolements contenant des plasmides ainsi que sur l'incidence des plasmides des souches non "Pseudomonas -like" provenant des mêmes endroits. La majorité (86%) des plasmides détectés ont une masse moléculaire entre 35 et 312 Md. Baya et al., 1986, ont fait une étude comparative entre 4 zones : 1) des eaux provenant d'une station qui reçoit surtout des déchets chimiques 2) des eaux proches de la station 3) des eaux océaniques contaminées par des rejets domestiques 4) des eaux propres utilisées comme contrôle. Les résultats obtenus montrent que le nombre de bandes plasmidiques par souche dans les différentes zones diminue dès la zone 1 vers la zone 4. L'objectif de notre travail est d'examiner dans un premier temps, le contenu plasmidique des souches d'E.coli venant des eaux brutes, eaux épurées et des eaux de la sortie de la station d'épuration de Morlaix. Et dans un deuxième temps, étudier l'évolution de ces plasmides dans l'environnement pendant différents temps de séjour.

La recherche des coliformes dans les milieux extérieurs, en particulier dans l'eau, par les techniques traditionnelles nécessite en premier, la filtration d'une quantité suffisante d'eau, suivie de la culture des filtres sur un milieu sélectif. Ceci permet d'identifier les bactéries utilisant le lactose en tant que seule source de carbone (Greenberg, 1985). Les Escherichia coli entérotoxigènes sont ensuite recherchés par les tests de détection de l'entérotoxine LT effectués sur le surnageant de la culture bactérienne. Ces tests sont basés sur l'activités biologique (culture sur cellules vero et Y1) ou immunologique (latex, GM1-ELISA, Biken, ...) et/ou radio-immunologique (Sack and Sack, 1975 ; Honda et al., 1981 ; Ito et al., 1983 ; Ristaino et al., 1983). Ces méthodes souvent coûteuses manquent de précision pour détecter spécifiquement une sorte de bactérie dans une grande quantité d'eau. Dans un échantillon donné d'environnement, il est possible de dénombrer un certain nombre de bactéries utilisant le lactose, mais, la production de toxine LT ne peut être associée qu'à la présence d'un petit nombre d'E.coli entérotoxinogènes.

Illnesses due to marine bivalvia consumption are mostly associated with viruses as causative agents. In more than the half of cases, this agent remains unidentifies, nevertheless. So far as bacteria are concerned, Salmonella are found firstly. Campylobacters represent a major cause of gastrointestinal disease, with Salmonella, among humans. Whether campylobacteriosis may be acquired from shellfishes remains unclear. We undertook to comparatively appreciate the survival of Campylobacter jejuni/coli and Salmonella typhimurium in seawater and contaminated mussels. Bacterial enumerations where performes using microbial cultures and specific (with immunofluorescence) direct viable counts (of substrate responsive bacteria). During laboratory contamination experiments, C. jejuni/coli and S. typhimurium are aforded together with unicellular microalgae Tetraselmis suecica. Mussels incorporate efficiently these microorganisms into their digestive tract (up 100 to 500 folds the concentration of contamination tank). In the gut of contaminated mussels, stored dry at 16 degree C, the number of culturable Salmonella remains constant after one week whereas C. jejuni persists in constant number of viable cells but exhibits a 10000 fold decrease of culturable bacteria. In seawater, Campylobacter survive poorly, compared with Salmonella: from comparable initial densities, the difference may reach a 106 factor after one week. The occurrence of mussel contamination with Salmonella is customary in polluted seawater: it should remain neglectible with Campylobacter. The cells of C. coli which survived after a 6 days stay into contaminated seawater and mussels maintained intacts virulence factors: mobility and adherence to cultured HeLa cells. This is at least true for bacteria remaining culturable, and questionable for viable non culturable cells. On the whole, shellfish born diseases due to Campylobacter should actually be possible (Griffin et al., 1983). This whould nevertheless represen

La recherche des coliformes dans les milieux extérieurs, en particulier dans l'eau, par les techniques traditionnelles nécessite en premier, la filtration d'une quantité suffisante d'eau, suivie de la culture des filtres sur un milieu sélectif. Ceci permet d'identifier les bactéries utilisant le lactose en tant que seule source de carbone (Greenberg, 1985). Les Escherichia coli entérotoxigènes sont ensuite recherchés par les tests de détection de l'entérotoxine LT effectués sur le surnageant de la culture bactérienne. Ces tests sont basés sur l'activités biologique (culture sur cellules vero et Y1) ou immunologique (latex, GM1-ELISA, Biken, ...) et/ou radio-immunologique (Sack and Sack, 1975 ; Honda et al., 1981 ; Ito et al., 1983 ; Ristaino et al., 1983). Ces méthodes souvent coûteuses manquent de précision pour détecter spécifiquement une sorte de bactérie dans une grande quantité d'eau. Dans un échantillon donné d'environnement, il est possible de dénombrer un certain nombre de bactéries utilisant le lactose, mais, la production de toxine LT ne peut être associée qu'à la présence d'un petit nombre d'E.coli entérotoxinogènes.

Peu d'études ont été réalisées sur la distribution, le transfert et les fonctions des plasmides existants dans les bactéries de l'environnement (Smith, 1970 ; Glasman et al., 1981 ; Hada et Sizemore, 1981). Hada et Sizemore (1981) en faisant une étude comparative sur le nombre des plasmides contenus dans 440 isolements de Vihrio marins du Golfe de Mexico ont démontré que l'incidence des plasmides est plus importante dans des isolements marins des sites pollués, que dans des isolements marins de sites non contaminés. Par contre, Burton et al. en 1982, en travaillant dans une rivière de South Wales, n'ont pas trouvé de différence significative entre les sites pollués et ceux non pollués sur le pourcentage total des isolements contenant des plasmides ainsi que sur l'incidence des plasmides des souches non "Pseudomonas -like" provenant des mêmes endroits. La majorité (86%) des plasmides détectés ont une masse moléculaire entre 35 et 312 Md. Baya et al., 1986, ont fait une étude comparative entre 4 zones : 1) des eaux provenant d'une station qui reçoit surtout des déchets chimiques 2) des eaux proches de la station 3) des eaux océaniques contaminées par des rejets domestiques 4) des eaux propres utilisées comme contrôle. Les résultats obtenus montrent que le nombre de bandes plasmidiques par souche dans les différentes zones diminue dès la zone 1 vers la zone 4. L'objectif de notre travail est d'examiner dans un premier temps, le contenu plasmidique des souches d'E.coli venant des eaux brutes, eaux épurées et des eaux de la sortie de la station d'épuration de Morlaix. Et dans un deuxième temps, étudier l'évolution de ces plasmides dans l'environnement pendant différents temps de séjour.

Illnesses due to marine bivalvia consumption are mostly associated with viruses as causative agents. In more than the half of cases, this agent remains unidentifies, nevertheless. So far as bacteria are concerned, Salmonella are found firstly. Campylobacters represent a major cause of gastrointestinal disease, with Salmonella, among humans. Whether campylobacteriosis may be acquired from shellfishes remains unclear. We undertook to comparatively appreciate the survival of Campylobacter jejuni/coli and Salmonella typhimurium in seawater and contaminated mussels. Bacterial enumerations where performes using microbial cultures and specific (with immunofluorescence) direct viable counts (of substrate responsive bacteria). During laboratory contamination experiments, C. jejuni/coli and S. typhimurium are aforded together with unicellular microalgae Tetraselmis suecica. Mussels incorporate efficiently these microorganisms into their digestive tract (up 100 to 500 folds the concentration of contamination tank). In the gut of contaminated mussels, stored dry at 16 degree C, the number of culturable Salmonella remains constant after one week whereas C. jejuni persists in constant number of viable cells but exhibits a 10000 fold decrease of culturable bacteria. In seawater, Campylobacter survive poorly, compared with Salmonella: from comparable initial densities, the difference may reach a 106 factor after one week. The occurrence of mussel contamination with Salmonella is customary in polluted seawater: it should remain neglectible with Campylobacter. The cells of C. coli which survived after a 6 days stay into contaminated seawater and mussels maintained intacts virulence factors: mobility and adherence to cultured HeLa cells. This is at least true for bacteria remaining culturable, and questionable for viable non culturable cells. On the whole, shellfish born diseases due to Campylobacter should actually be possible (Griffin et al., 1983). This whould nevertheless represen

Peu d'études ont été réalisées sur la distribution, le transfert et les fonctions des plasmides existants dans les bactéries de l'environnement (Smith, 1970 ; Glasman et al., 1981 ; Hada et Sizemore, 1981). Hada et Sizemore (1981) en faisant une étude comparative sur le nombre des plasmides contenus dans 440 isolements de Vihrio marins du Golfe de Mexico ont démontré que l'incidence des plasmides est plus importante dans des isolements marins des sites pollués, que dans des isolements marins de sites non contaminés. Par contre, Burton et al. en 1982, en travaillant dans une rivière de South Wales, n'ont pas trouvé de différence significative entre les sites pollués et ceux non pollués sur le pourcentage total des isolements contenant des plasmides ainsi que sur l'incidence des plasmides des souches non "Pseudomonas -like" provenant des mêmes endroits. La majorité (86%) des plasmides détectés ont une masse moléculaire entre 35 et 312 Md. Baya et al., 1986, ont fait une étude comparative entre 4 zones : 1) des eaux provenant d'une station qui reçoit surtout des déchets chimiques 2) des eaux proches de la station 3) des eaux océaniques contaminées par des rejets domestiques 4) des eaux propres utilisées comme contrôle. Les résultats obtenus montrent que le nombre de bandes plasmidiques par souche dans les différentes zones diminue dès la zone 1 vers la zone 4. L'objectif de notre travail est d'examiner dans un premier temps, le contenu plasmidique des souches d'E.coli venant des eaux brutes, eaux épurées et des eaux de la sortie de la station d'épuration de Morlaix. Et dans un deuxième temps, étudier l'évolution de ces plasmides dans l'environnement pendant différents temps de séjour.

La recherche des coliformes dans les milieux extérieurs, en particulier dans l'eau, par les techniques traditionnelles nécessite en premier, la filtration d'une quantité suffisante d'eau, suivie de la culture des filtres sur un milieu sélectif. Ceci permet d'identifier les bactéries utilisant le lactose en tant que seule source de carbone (Greenberg, 1985). Les Escherichia coli entérotoxigènes sont ensuite recherchés par les tests de détection de l'entérotoxine LT effectués sur le surnageant de la culture bactérienne. Ces tests sont basés sur l'activités biologique (culture sur cellules vero et Y1) ou immunologique (latex, GM1-ELISA, Biken, ...) et/ou radio-immunologique (Sack and Sack, 1975 ; Honda et al., 1981 ; Ito et al., 1983 ; Ristaino et al., 1983). Ces méthodes souvent coûteuses manquent de précision pour détecter spécifiquement une sorte de bactérie dans une grande quantité d'eau. Dans un échantillon donné d'environnement, il est possible de dénombrer un certain nombre de bactéries utilisant le lactose, mais, la production de toxine LT ne peut être associée qu'à la présence d'un petit nombre d'E.coli entérotoxinogènes.

Illnesses due to marine bivalvia consumption are mostly associated with viruses as causative agents. In more than the half of cases, this agent remains unidentifies, nevertheless. So far as bacteria are concerned, Salmonella are found firstly. Campylobacters represent a major cause of gastrointestinal disease, with Salmonella, among humans. Whether campylobacteriosis may be acquired from shellfishes remains unclear. We undertook to comparatively appreciate the survival of Campylobacter jejuni/coli and Salmonella typhimurium in seawater and contaminated mussels. Bacterial enumerations where performes using microbial cultures and specific (with immunofluorescence) direct viable counts (of substrate responsive bacteria). During laboratory contamination experiments, C. jejuni/coli and S. typhimurium are aforded together with unicellular microalgae Tetraselmis suecica. Mussels incorporate efficiently these microorganisms into their digestive tract (up 100 to 500 folds the concentration of contamination tank). In the gut of contaminated mussels, stored dry at 16 degree C, the number of culturable Salmonella remains constant after one week whereas C. jejuni persists in constant number of viable cells but exhibits a 10000 fold decrease of culturable bacteria. In seawater, Campylobacter survive poorly, compared with Salmonella: from comparable initial densities, the difference may reach a 106 factor after one week. The occurrence of mussel contamination with Salmonella is customary in polluted seawater: it should remain neglectible with Campylobacter. The cells of C. coli which survived after a 6 days stay into contaminated seawater and mussels maintained intacts virulence factors: mobility and adherence to cultured HeLa cells. This is at least true for bacteria remaining culturable, and questionable for viable non culturable cells. On the whole, shellfish born diseases due to Campylobacter should actually be possible (Griffin et al., 1983). This whould nevertheless represen

The behaviour of fecal bacteria was investigated in a turbid estuary which is also a shellfishing area. Sediments are polluted by sewage by the way of settlement, fecal bacteria mixed with estuarine water being able to survive a very long time (T90 are about several days). By measuring the increase of salt tolerance of the strains grown in natural estuarine organic matter, it was demonstrated that Escherichia coli is able to support the salinity of coastal water. Moreover, because light penetration is obstructed by suspended matter, the solar bactericidal effect is very low. A close relationship between T90 and light intensity received by the bacteria is found. These mechanisms can explain the low die-off rate found in turbid areas.

The behaviour of fecal bacteria was investigated in a turbid estuary which is also a shellfishing area. Sediments are polluted by sewage by the way of settlement, fecal bacteria mixed with estuarine water being able to survive a very long time (T90 are about several days). By measuring the increase of salt tolerance of the strains grown in natural estuarine organic matter, it was demonstrated that Escherichia coli is able to support the salinity of coastal water. Moreover, because light penetration is obstructed by suspended matter, the solar bactericidal effect is very low. A close relationship between T90 and light intensity received by the bacteria is found. These mechanisms can explain the low die-off rate found in turbid areas.

The behaviour of fecal bacteria was investigated in a turbid estuary which is also a shellfishing area. Sediments are polluted by sewage by the way of settlement, fecal bacteria mixed with estuarine water being able to survive a very long time (T90 are about several days). By measuring the increase of salt tolerance of the strains grown in natural estuarine organic matter, it was demonstrated that Escherichia coli is able to support the salinity of coastal water. Moreover, because light penetration is obstructed by suspended matter, the solar bactericidal effect is very low. A close relationship between T90 and light intensity received by the bacteria is found. These mechanisms can explain the low die-off rate found in turbid areas.

The behaviour of fecal bacteria was investigated in a turbid estuary which is also a shellfishing area. Sediments are polluted by sewage by the way of settlement, fecal bacteria mixed with estuarine water being able to survive a very long time (T90 are about several days). By measuring the increase of salt tolerance of the strains grown in natural estuarine organic matter, it was demonstrated that Escherichia coli is able to support the salinity of coastal water. Moreover, because light penetration is obstructed by suspended matter, the solar bactericidal effect is very low. A close relationship between T90 and light intensity received by the bacteria is found. These mechanisms can explain the low die-off rate found in turbid areas.

Superfluorescence emission profiles are computed using one-way coupled Maxwell-Bloch equations. Transverse effects are included in the full three-spatial-dimension case as well as in the cylindrical-symmetry case. Initiating quantum fluctuations are approximated by a random polarization source with a completely random phase and root-mean-square tipping angle of 2 square root of N, where N is the number of atoms in each volume element. These fluctuations reduce the tail of the output pulse shapes encompass the Cs data of Gibbs, Vrehen, and Hikspoors. The standard deviation for the delay time is found to be (12.5 + or -4)% for Fresnel number of 0.8 compared with the value (10 + or - 2)% recently measured by Vrehen and der Weduwe, also for Cs. Inhomogeneous-broadening effects are also included in some simulations. Additional keywords: Reprints; Army research; Fresnel integrals.

Near outfall areas numerous bacteria appear associated to colloidal organic matter present in littoral sea water. Arrangements into colonies are shown. Surface structures are observed which allow bacteria's attachment each to other and to organic matter., Près des zones de rejets, de nombreuses bactéries sont associées aux colloïdes organiques présents dans l'eau de mer littorale. Elles forment des microcolonies. Des structures d'adhésion permettent des relations entre bactéries et matière organique.

The principle of this method is to evaluate, by counts exercised upon selective media, the relative importance of the different bacteria families in the flora of the coastal waters. It is important to separate the contaminant species and the commensal species in the marine environment. Ten culture media distributed into four categories (selective, non selective, saline and non saline) were examined by numeration. Counts were transferred on a diagram allowing to plot down a profile of bacterial flora of water sampled from a given geographical area. The profiles are arranged by a classification method. The sampling points with similar or adjoining profiles were assembled and marked on the chart. In this way, the authors obtained areas representing the impact zone of disposal of disturbed zones of flora that have remained stable during this study., Le principe de la méthode est d'évaluer, grâce à des numérations sur milieux sélectifs, l'importance relative des différentes familles bactériennes dans la flore des eaux de mer littorales. Il est important de séparer milieux de cultures, répartis en quatre classes : milieux sélectifs, non sélectifs, salés, non salés. Les numérations sont reportées sur un diagramme permettant d'établir un profil de la flore bactérienne de l'eau prélevée en un point géographiquement donné. Les profils sont groupés par une méthode de classification. Les points de prélèvements dont les profils sont semblables ou voisins sont rassemblés et repérés sur la carte. Nous obtenons pendant la durée de l'étude.

The principle of this method is to evaluate, by counts exercised upon selective media, the relative importance of the different bacteria families in the flora of the coastal waters. It is important to separate the contaminant species and the commensal species in the marine environment. Ten culture media distributed into four categories (selective, non selective, saline and non saline) were examined by numeration. Counts were transferred on a diagram allowing to plot down a profile of bacterial flora of water sampled from a given geographical area. The profiles are arranged by a classification method. The sampling points with similar or adjoining profiles were assembled and marked on the chart. In this way, the authors obtained areas representing the impact zone of disposal of disturbed zones of flora that have remained stable during this study., Le principe de la méthode est d'évaluer, grâce à des numérations sur milieux sélectifs, l'importance relative des différentes familles bactériennes dans la flore des eaux de mer littorales. Il est important de séparer milieux de cultures, répartis en quatre classes : milieux sélectifs, non sélectifs, salés, non salés. Les numérations sont reportées sur un diagramme permettant d'établir un profil de la flore bactérienne de l'eau prélevée en un point géographiquement donné. Les profils sont groupés par une méthode de classification. Les points de prélèvements dont les profils sont semblables ou voisins sont rassemblés et repérés sur la carte. Nous obtenons pendant la durée de l'étude.

Near outfall areas numerous bacteria appear associated to colloidal organic matter present in littoral sea water. Arrangements into colonies are shown. Surface structures are observed which allow bacteria's attachment each to other and to organic matter., Près des zones de rejets, de nombreuses bactéries sont associées aux colloïdes organiques présents dans l'eau de mer littorale. Elles forment des microcolonies. Des structures d'adhésion permettent des relations entre bactéries et matière organique.

Near outfall areas numerous bacteria appear associated to colloidal organic matter present in littoral sea water. Arrangements into colonies are shown. Surface structures are observed which allow bacteria's attachment each to other and to organic matter., Près des zones de rejets, de nombreuses bactéries sont associées aux colloïdes organiques présents dans l'eau de mer littorale. Elles forment des microcolonies. Des structures d'adhésion permettent des relations entre bactéries et matière organique.

The principle of this method is to evaluate, by counts exercised upon selective media, the relative importance of the different bacteria families in the flora of the coastal waters. It is important to separate the contaminant species and the commensal species in the marine environment. Ten culture media distributed into four categories (selective, non selective, saline and non saline) were examined by numeration. Counts were transferred on a diagram allowing to plot down a profile of bacterial flora of water sampled from a given geographical area. The profiles are arranged by a classification method. The sampling points with similar or adjoining profiles were assembled and marked on the chart. In this way, the authors obtained areas representing the impact zone of disposal of disturbed zones of flora that have remained stable during this study., Le principe de la méthode est d'évaluer, grâce à des numérations sur milieux sélectifs, l'importance relative des différentes familles bactériennes dans la flore des eaux de mer littorales. Il est important de séparer milieux de cultures, répartis en quatre classes : milieux sélectifs, non sélectifs, salés, non salés. Les numérations sont reportées sur un diagramme permettant d'établir un profil de la flore bactérienne de l'eau prélevée en un point géographiquement donné. Les profils sont groupés par une méthode de classification. Les points de prélèvements dont les profils sont semblables ou voisins sont rassemblés et repérés sur la carte. Nous obtenons pendant la durée de l'étude.

Near outfall areas numerous bacteria appear associated to colloidal organic matter present in littoral sea water. Arrangements into colonies are shown. Surface structures are observed which allow bacteria's attachment each to other and to organic matter., Près des zones de rejets, de nombreuses bactéries sont associées aux colloïdes organiques présents dans l'eau de mer littorale. Elles forment des microcolonies. Des structures d'adhésion permettent des relations entre bactéries et matière organique.

The principle of this method is to evaluate, by counts exercised upon selective media, the relative importance of the different bacteria families in the flora of the coastal waters. It is important to separate the contaminant species and the commensal species in the marine environment. Ten culture media distributed into four categories (selective, non selective, saline and non saline) were examined by numeration. Counts were transferred on a diagram allowing to plot down a profile of bacterial flora of water sampled from a given geographical area. The profiles are arranged by a classification method. The sampling points with similar or adjoining profiles were assembled and marked on the chart. In this way, the authors obtained areas representing the impact zone of disposal of disturbed zones of flora that have remained stable during this study., Le principe de la méthode est d'évaluer, grâce à des numérations sur milieux sélectifs, l'importance relative des différentes familles bactériennes dans la flore des eaux de mer littorales. Il est important de séparer milieux de cultures, répartis en quatre classes : milieux sélectifs, non sélectifs, salés, non salés. Les numérations sont reportées sur un diagramme permettant d'établir un profil de la flore bactérienne de l'eau prélevée en un point géographiquement donné. Les profils sont groupés par une méthode de classification. Les points de prélèvements dont les profils sont semblables ou voisins sont rassemblés et repérés sur la carte. Nous obtenons pendant la durée de l'étude.