Stabilité biologique des réseaux de distribution d'eau potable

The maintenance of the quality of water from the outlet of the treatment plant to the consumer tap is a major concern of water distributors. From a biological point of view, this maintenance must be characterized by a stability of biological features, namely bacterial growth from biodegradable organic matter, and protozoan bacterivory which must be not detectable. However, drinking water distribution systems are continuously exposed to a flow of biodegradable organic matter, which can represent around 20–30 % of the total dissolved organic carbon, and a flow of allochthonous microorganisms (bacteria, fungi, protozoa…), coming from the water treatment plant but also from incidents (breaks/repairs) on the distribution network itself. Apart from these microorganisms (heterotrophic bacteria in particular) can grow in this ultra-oligotrophic environment and colonize the all drinking water distribution system. The highest density of microorganisms occurs on the surface of pipewalls where they are organized in microcolonies (biofilm) that are mixed with corrosion products and inorganic precipitates. Five groups of organisms have been identified in distribution networks, in both the water phase and the biofilm: bacterial cells, protozoa, yeast, fungi and algae. The majority of these organisms are not pathogens, nevertheless potentially pathogen bacteria (Legionella…), fecal bacteria (coliforms, E. coli…), and pathogen protozoan cysts (Giardia intestinalis, Cryptosporidium parvum…) can transitorily find favorable conditions for their proliferation in the networks. Bacteria grow from the biodegradable fraction of dissolved organic matter while protozoa grow from dissolved organic matter, other protozoa but especially from bacterial prey items. The protozoan bacterivory was extensively studied in marine aquatic environments and in rivers, lakes,… but very rarely in drinking water distribution networks. Actually, proofs of the protozoan grazing on fixed and free-living bacterial cells were given by photography or film of biofilms accumulation on coupons that were previously immersed in potable water or by direct microscopic observation of bacteria in food vacuole of protozoa from potable water. A single and recent study has estimated protozoan bacterivory rate from laboratory experiences using fluorescent markers. It appears that in an experimental distribution system fed with biologically treated water (ozone/filtration through granular activated carbon), only ciliates present in the biofilm have a measurable grazing activity, estimated at 2 bacteria·ciliate⁻¹·h⁻¹ on average.Bacterial dynamics in drinking water distribution systems is complex and related to different parameters, like the biodegradable fraction of dissolved organic carbon, the presence of a residual of disinfectant, the nature and the state of pipewalls, the relative biomass of free and fixed bacterial, and grazing impact.The preservation of the biological stability of potable water during its storage in reservoir or its transport through the distribution systems can be achieved by (a) the use of chemical disinfectants (in particular by addition of chlorine) which is the widely used technique, or (b) the use of new techniques such as nanofiltration that can eliminate bacteria and significantly decrease the concentrations of organic matter at the inlet of the distribution network and in the potable water.

• (a)The use of oxidant, usually chlorine, induces a number of problems, in particular the development of oxidation by-products like trihalomethans (THM), among which some are recognized as carcinogenic products for animals. In addition, chlorine added at the outlet of treatment plant is consumed in the network and the maintenance of a residual of chlorine along an entire distribution network would need high concentrations of chlorine at the outlet of the treatment plant. This may be incompatible with standards for both residual chlorine and its by-products. Nevertheless, chlorine has a disinfectant effect on planctonic bacteria, if considering that only around 10 % of free bacterial cells are living cells, i.e. are able of respiratory oxidation. However, some studies show that bacteria fixed on granular activated carbon particles can be resistant to chlorine, as well as bacteria in aggregates. Thus, the addition of chlorine in potable water does not inhibit the formation of a biofilm at the surface of pipewalls. In the same way, protozoa transported by potable water can resist to chlorine.
• (b)The above disadvantages permitted the development of membrane filtration techniques like the nanofiltration, which is at the junction between reverse osmosis and ultrafiltration, and which seems to be an interesting alternative to conventional treatments because it presents the advantage to (i) decrease very strongly the concentrations of dissolved organic carbon (on average 90 % for DOC (Dissolved Organic Carbon) and 99 % for BDOC (Biodegradable Dissolved Organic Carbon)), (ii) to remove a very high proportion of almost the entire microorganisms (99 %), precursors of chlorination by-products, and micropollutans, (iii) to decrease the musty flavor of water (2-fold) and (iv) to produce a water that needs low concentration of chlorine.

     

Classification des stades de sommeil par des réseaux de neurones artificiels hiérarchiques

The goal of our work is to provide an automatic analysis and decision tool for sleep stages classification based on an artificial neural networks (ANN). The first difficulty lies in choosing the physiological signals representation and in particular the electroencephalogram (EEG). Once the representation adopted, the next step is to design the optimal neural network determined by a learning and validation process of data from a set of sleep records. We studied several configurations of conventional ANN giving results varying from 62 to 71 %, then we proposed a new hierarchical configuration, which gives a rate of 74 % correct classification for six stages. These results lead us to further explore this issue at the representation and design of ANNs to improve the performance of our tool.     

Les micrasterias de la région des Trois-Riviéres

Sans résuméLa Pointe-du-Lac, P. Q.     

Les Actinomycoses rénales

Sans résumé     

Les corps myeloïdes de l'epithelium pigmentaire rétinien

Résumé Les corps myéloïdes de l'épithélium pigmentaire rétinien ont été observés après différentes techniques de fixation, déshydratation, inclusion et coloration. Après fixation classique par le glutaraldéhyde et l'osmium, l'espace intersacculaire apparaît réduit (jonctions) et une ligne dense est parfois observable dans l'espace intrasacculaire. La fixation par le permanganate met en évidence de façon permanente cette ligne dense qui correspondrait à la fusion des membranes. La coloration négative caractérise un constituant protéique entre les saccules. La déshydratation par le Durcupan hydrosoluble met en évidence un matériel lipidique intrasacculaire qui est extrait par le méthanol-chloroforme et partiellement par la déshydratation alcoolique classique.Les corps myéloïdes apparaissent plusieurs jours avant l'éclosion chez l'oiseau. Ils se forment à partir du réticulum granulaire. Ils ne peuvent être confondus avec les dictyosomes Golgiens : Ils ne contiennent pas de glycoprotéines.

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Summary Myeloid bodies of the retinal pigment epithelium of different vertebrates were investigated by various techniques of fixation, dehydration, embedding and staining. After classical fixation with buffered glutaraldehyde and osmium, the intersaccular space is narrow (junction complexes) and a dense line is sometimes visible in the middle of the intrasaccular space. With permanganate fixative this dense line is always visible; it represents probably the fusion of the unit-membranes. The negative staining demonstrates the presence of proteins between the saccules. Dehydration by water soluble Durcupan shows a lipidic component in the intrasaccular space, which is removed by methanol-chloroform and partly by the classical ethanol dehydration.The existence of myeloid bodies is demonstrated in the bird-embryo a few days before birth. They originate from granular reticulum cisternae. They are not of Golgi origin: glycoprotein cannot been demonstrated at their level.

Chargé de Recherche à l'I.N.S.E.R.M. (contrat n° 711.152). Avec la collaboration technique de L. Salin et D. Joseph.     

Méthode simple et rapide de réalisation de microculture en identification mycologique

Résumé On décrit deux moyens de réalisation de microculture dans l'identification de champignons filamenteux qui sont comparés avec la méthode classique. Le premier d'entre eux se réalise par ensemencement moyennent l'inondation du milieu en boîte de Petri avec suspension de spores et est ensuite coupé en carrés que l'on place à l'intérieur de boîte de Petri. Le second consiste à suspendre micelium fongique en milieu fluide à 50°C. Les deux ont l'avantage de la rapidité de réalisation, surtout quand on doit préparer un grand nombre de microcultures dans le but de l'enseignement et que l'on ne dispose pas des éléments stériles pour la réalisation de la microculture sur les lames.     

Les hyménoptères parasites de la mouche des olives I. Les chalcidiens de la région méditerranéenne

Summary In this brief work, authors study the five Chalcidids parasites of the olivefly in the mediterranean zone and discuss the systematic point of view. They modify the generic name (Cyrtoptyx, Pnigalio) and show the existence of the new speciesP. mediterraneus; this name substitutes the other nameE. longulus Zett which was wrongly given to theDacus's parasite. A table has been done for the rapid identification of the five species of Chalcidids.

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Riassunto Nel presente breve lavoro, gli AA. riprendono lo studio dei cinque Calcididi parassiti della mosca delle olive nella zona mediterranea, ne discutono il valore dal punto di vista sistematico, ne modificano la denominazione generica (Cyrtoptyx, Pnigalio) e mettono in evidenza l'esistenza della nuova specieP. mediterraneus, il cui nome sostituisce quello diE. longulus Zett., erroneamente attribuito al parassita delDacus. E'stata compilata una tabella per l'identificazione rapida di queste cinque specie di Calcididi.

     

Les résidents et l'enseignement: revue de la littérature.

We reviewed the available data on residents'' teaching role in the clinical setting to develop programs to improve their teaching skills. Articles published from 1966 to 1989 were identified through a computerized search of MEDLINE, and the bibliographies of identified papers were reviewed. Articles directly related to the topic were included and analysed. Taking into account their quality, we extracted data relevant to specific issues. Approximately 15% to 25% of an average work week was spent by residents in different teaching activities. Students acknowledged the importance of their contribution to clinical teaching. Residents benefitted from teaching by increasing their medical knowledge and promoting the development of important attitudes. Insufficient preparation for this task and the numerous practical problems faced by residents may explain their modest performance as teachers. Nevertheless, programs directed to residents might improve the quality of their teaching. We suggest some guidelines for the development of programs to improve their teaching skills and for future research.     

Les théories de l’économie animale et l’émergence de la psychiatrie de l’Encyclopédie à l’aliénisme

The author analysesEncyclopédie’s articles devoted to nervous and mental functioning and disorders, showing that a new approach to lunacy as a mental illness, which is defined in some articles as a “general trouble of the animal economy”, progressively emerged. The term,animal economy, unified physical and moral aspects of the study of man. It was elaborated by XVIIIth century physiologists and was widely accepted by French physicians. This idea is based on the vitalistic thought of the Montpellier school, which equated life with sensibility, and on English medical conceptions of a nervous-centred organism. Later on Philippe Pinel’s work displayed the legacy of these conceptions. On one hand, the comprehensive view of physical and moral dimensions in theanimal economy neutralized the question of an organic or psychogenetic origin of madness. This enabled him to consider it as a determinate field of sensibility interactions and as a medical matter, and to legitimize the group of therapeutic practices that he namedtraitement moral. On the other hand, Pinel departed from the classical conception ofanimal economy by developing his concept of aprinciple of mania, which underlies the manifold symptoms and forms of madness, and which are only perceptible to a trained specialist (aliéniste). The historical development analysed in this article show how alienists were enabled to claim both the wholly medical nature of insanity as disease, and their specific competence as apart from the other medical disciplines. To this extent, Esquirol achieved Pinel’s scientific work.     

Les formes zoogènes de tufs et leur formation dans la région des Lacs de Plitvice en Yougoslavie

Résumé En cours de cette etude ont été énoncées les données concernant la manifestation de tufs zoogènes dans les eaux qui ravitaillent les lacs de Plitvice en Yougoslavie. Outre le tuf chironomide qu'on y trouve représenté sous trois types: oocardien, cratoneuronien et platyhypnidien, il a été établi qu'à l'endroit où se rencontrent la Crna rijeka et Bijela rijeka, on rencontre un type particulier de tuf trichoptere. Ce tuf se forme par l'action du trichoptère Stenophylax et Rhyacophila, ainsi que par l'action du gastropode Lithoglyphus fluminensis. Par leurs gangues et leurs coquilles, ils maintiennent les parcelles de calcaire sécrétées par voie abiogène. Ainsi se forme un substrat calcareux sur lequel viennent se poser ensuite des cyanoficées et des desmidiacées ∘ocardium stratum qui forwent can tuf de caractère lacustre. Quoiqu'à l'origine ces tufs soient différents, ils forwent can tout. Un peu plus bas dans la rivière, se forme can tuf semblable avec cette seule différence que son substrat est formé aussi de tufs cyanoficées et oocardiens, car ici la seule base solide est formée par des branches et des troncs. Nous signalons pour finir que le reste du tuf en cet endroit n'est pas conditionné seulement par des facteurs biogènes simples, mais que vraisemblablement d'autres composants agissent dans lesquels notamment des animaux jouent can r?le.

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Zusammenfassung In dieser Verhandlung haben die Autoren besondere Angaben über das Vorkommen des zoogenen Tuffes im Gebiete der Verpflegungsgew?sser von Plitvička jezera in Jugoslawien mitgeteilt. Nebst dem Chironomidentuff, welcher hier in drei verschiedenen Formen, als Ookardischer-, Kratoneuronischer- und Platyhypnidischer Chironomidentuff vorkommt, wurde festgestellt, dass in den Verbindungsgebieten der Flüsse Crna rijeka und Bijela rijeka, noch eine besondere Form des Tuffes, sogenanter Trichopterentuff erscheint. Diese Form des Tuffes kommt durch die Mitwirkung der Larven von K?cher-fliegen Stenophylax and Rhyacophila und Schnecken Lithoglyphus fluminensis zustande. Kalkteilchen werden von ihren K?chern und Geh?usen zurückgehalten, und auf diese Weise durch einen abiogenen Vorgang ausgeschieden. Auf dieser so entstandenen Kalkunterlage siedeln sich nachdem Cyanophyceen, und von den Desmidiaceen Oocardium stratum an. Dieser Tuff hat einen durchwegs lakustrischen Charakter. Obwohl die genannten Tuffe ihrer Entstehung nach verschieden sind, stellen she doch eine einheitliche Erscheinung. In etwas abw?rts gelegener Richtung entsteht eine ?hnliche Form des Tuffes, nur wit dem Unterschied, dass der Untergrund hier auch als Oocardium-und Spaltalgen-Tuff ausgebaut ist, da in diesen Falle die einzige feste Unterlage von Zweigen und Balken gebildet wird. Endlich wurde noch darauf hingewiesen, dass auch aller übrige Tuff in diesem Gebiete nicht nur von biogenen Faktoren abh?ngt, sondern dass wahrscheinlich noch andere Vorg?nge bei seiner Bildung beteiligt sind. Dabei kommt auch den Tieren ein gewisser Anteil zu.

     

Les profils de composition en oligoéléments des pollens,marqueurs potentiels en cladistique végétale

In botany tentative attempts have been made to classify species, based not on the plant as a whole, but on a particular character, for example pollen characteristics. Pollen, which is involved in the transmission of male genetic information during sexual reproduction, is of particular interest in distinguishing plants and their relationships.

These characters, observed in photon- and scanning electron- microscopy are symmetry, form, number and position of germinating areas. Being genetically stable for a given species, they identify a plant.

Recently, a novel character has been added: the concentration of elements in the exine, determined by electron probe micro-X-ray analysis. It is interesting to follow relationship of plant species, based on the mineral composition of their pollen as a whole, taking into account both plastic and oligoelements, obtained via an inductive coupled plasma spectrometer. Samples of pollen from different plant species, at distinct taxonomic levels, were analyzed; the results were submitted to a normalisation procedure and the standard patterns obtained were investigated by means of a number of numerical techniques (clustering and factor analysis). The aim was to establish if elements could be considered as chemical markers in plant cladistics. The mineral composition in a given species appeared quite stable and this furnished a convenient identification-critorion.

This approach further allows a chemo-taxonomy of species, in as much as organization of families, and perhaps orders, would conform to the phylogenetic proximity-criterion. Hence, we found clusters including pollen of Gramineae, Coniferae, Betulaceae…

This methodology, that should be completed and corroborated on a wider range of samples would provide an original responsee to the problems of identification and classification encountered in a pollen bank. It follows that:

Hence, the working hypothesis that the chemical markers and, in particular, oligo-elements, complete pollen typologies based on morphological and structural characters, appears quite reasonable.

In conclusion, this paper brings a complement to the mineral composition of the exine.

En botanique, des tentatives ont été faites pour classer les espèces non plus à partir d'individus pris dans leur intégralité, mais sur la base d'une de leurs particularités, par exemple à partir des caractéristiques offertes par les pollens. Ainsi, le pollen, dont le rôle est de transmettre l'information génétique mâle de la plante au moment de la reproduction sexuée, présente des caractères de premier ordre utilisables pour distinguer les différentes plantes et pour situer leur parenté et leur filiation.

Ces caractères, que l'on observe en microscopies photonique et électronique à balayage sont la symétrie, la forme, le nombre et la position des zones germinatives. Pour une espèce génétiquement stable, ils constituent la carte d'identité de la plante.

Il est intéressant de continuer à explorer la voie de la structuration des espèces végétales basée sur la connaissance chimique du pollen en déterminant sa composition en oligo-éléments par l'utilisation d'un spectromètre à plasma à couplage inductif. Ainsi, des échantillons de pollens appartenant à diverses espèces végétales situées à différents niveaux taxinomiques ont été analysés et les résultats normalisés sous forme de profils standard ont été soumis à différentes techniques d'analyse statistique mathématique (classification automatique et analyse factorielle). Le but de cette approche est d'apprécier l'aptitude des éléments minéraux à être des marqueurs chimiques en cladistique végétale.

Les résultats obtenus ont permis de constater la relative stabilité du profil en composition minérale au sein d'une même espèce végétale, ce qui donne accès à un critère d'identification commode.

Cette approche permet d'autre part une chimiotaxinomie des plantes étudiées.

Cette approche méthodologique semble susceptible d'apporter une réponse originale aux problèmes de conservation. Les pollens conservés doivent avoir la même composition minérale que les pollens frais.

— the pattern of pollen composition of oligo-elements, calcium and magnesium is a marker in plant cladistics. Since a typology depending on proximity is found between plant species, families and orders.

— an unknown pollen sample may be located, tentatively, on the base of a described model of pollen relation (shortest connexion network — Prim algorithm — and pollen of Bactris-oil palm and Phoenix dactylifera).