Etude du cycle nycthéméral de la teneur en oxygène dissous en bassins de pisciculture par la méthode des moyennes mobiles. Relation avec la température et l'insolation

Dans ce travail, le cycle journalier de l'oxygène dissous en bassins de pisciculture semi-intensive a été étudié en relation avec des données météorologiques. Nous disposions pour cela de 22 semaines d'enregistrements (mesures horaires) de janvier 1988 à décembre 1989, dont une semaine de mesures sous glace. Chaque période de mesures a été traitée comme une série chronologique en pratiquant une décomposition saisonnière par la méthode des moyennes mobiles qui permet d'extraire à partir d'une série de mesures la tendance sur la période étudiée et la composante journalière.Cette méthode, montre que le cycle nycthéméral de l'oxygène dissous garde son aspect et classique toute l'année, excepté sous la glace. Toutefois, l'amplitude journalière de la teneur en oxygène varie beaucoup selon la saison, et nous avons pu distinguer une période estivale où le métabolisme de l'étang semblait accéléré. L'analyse du cycle nycthéméral de l'oxygène dissous, dans lequel on distingue production et consommation, comparé à ceux de la température de l'eau et de l'insolation journalière moyenne, a permis d'étudier ce phénomène et de montrer l'importance des facteurs météorologiques dans la détermination du bilan de l'oxygène dissous en étang.Dissolved oxygen is a very important factor in fish ponds, particularly under intensive conditions. Thus, the daily fluctuations of dissolved oxygen have been studied in different countries and under different conditions (lakes, ponds, rivers), but with data series generally limited to a few measurements per day. The automatic data recorder of the IRRA'S experimental station provides very long series of data concerning of dissolved oxygen, temperature and meteorological factors through hourly measurements which allow the use of mathematical analysis like the moving average method. This automatic data recorder bas been in use since September 1987 and the data obtained have been analysed in research on summer oxygen deficit prevention. After 3 years' measurements it was interesting to investigate the annual change in the daily fluctuations of the dissolved oxygen. For this, daily hourly measurements of dissolved oxygen, temperature and solar radiations were taken and examined during 22 weeks from January 1988 to December 1989 (one week under ice cover). Oxygen data were analysed using seasonal decomposition by the moving average method, and the results were compared with the temperature and solar radiation measurements.The measurements were taken from 6 of the 16 IRRA'S experimental ponds (in the Dombes region, to the North-East of Lyon, France) and in a fish pond. All these ponds were semi-intensive fish-ponds stocked with Carp (Cyprinus carpio) Tench, (Tinca tinca), Grass Carp (Ctenopharingodon idella) and Silver Carp (Hypophthalmichthys molitrix).The seasonal decomposition through the moving average method devides the time series data into a trend (long term fluctuations), seasonal indices (or daily component) and residuals, but only seasonal indices, representing the daily variations, are studied here. The daily component was next spin into oxygen production and consumption if respiration is taken to be constant over one day and can be evaluated through the night oxygen decrease (EDELINE et al., 1968; ROMAIRE and BOYD, 1978; BARTHELEMY and COUTURE, 1990).Through this method, it appeared that the daily fluctuations of dissolved oxygen had the same classical aspect all the year round, except under ice cover, where it was impossible to observe a significant oxygen production. Such fluctuations, which are the result of the effect of oxygen production and consumption, have also been observed under different conditions (BOUD and LICHTKOPPLER, 1979; SIN and CHIU,1982; KEPENYES and VARADI, 1984; MARZOLF and SAUNDERS, 1984; GINOT, 1988; COUTURE, 1988). The aspect of the daily cycles was relatively constant but it was possible to distinguish 3 periods according to the amplitude of these cycles :- a winter period with less than 2 mg/l daily variations,- a summer period when these variations were greater titan 4 or 7 mg/l,- an intermediate period in spring and autumn.As these 3 periods did not occur at the same time of the year for 1988 & 1989, it appeared that the meteorological conditions (temperature and solar radiations) were important factors for determining these periods in the year.The study of oxygen production and consumption gave the same conclusions.These results have been compared with meteorological data : mean water temperature over 7-day periods (168 measurements), plus mean cumulative daily solar radiations over 7 days.There appeared significant correlations between the oxygen production and the consumption, with these meteorological factors, but these relations were different for the « summer » period (June to October) and the rest of the year. There was a delay between the period when temperature and solar radiations are best for primary production (June and July) and the period when the pond’s metabolism is maximum.There have been no measurements on primary production or algal population dynamics to explain these results clearly, but considering the observations of GRYGIEREK and WASILEWSKA (1979) and ELORANTA (1985) it is possible to give an explanation. In May-June the ponds are characterized by clear water (a higher than 60 cm transparency was observed) with low density algal populations, thus the pond ecosystem is not ready to use thermic and light energy. This delay between meteorological conditions and oxygen dynamics have been observed by ELORANTA (1985) and BOYD (1985).These results are useful in pond management, particularly when it is necessary to prevent oxygen depletion. The risk of oxygen deficits is greater in August-September, when the ecological conditions are very unstable owing to the important daily oxygen fluctuations. In this case, meteorological changes like temperature decreases or rain-fall can perturb the ecosystem and cause algal die-off with a great risk of oxygen depletion.The aim of this study was to show the possibilities of seasonal decomposition by the moving average method in the analysis of oxygen measurements. When it is possible to get long serie data, with constant skip, this method is very valuable for studying long term and daily fluctuations. The decomposition of the daily component through the method of EDELINE et al. (1968) also gives indications on primary production and oxygen consumption

Etude de l'influence de la température sur la compressibilité et la résistance à la rupture de matériaux granulaires

9 pagesLes poudres sont couramment utilisées sous forme de comprimés. Le comportement de ces poudres est sensible à différents paramètres tels que la température et l'humidité. La plupart des études de comportement ont porté sur l'influence des paramètres contrôlant la compression mais très rarement sur l'influence des paramètres extérieurs. Aussi avons nous choisi d'étudier l'influence de la température au cours du cycle de compression sur la compressibilité et sur les caractéristiques finales des comprimés obtenus à partir d'un composé organique fixé. Des expériences ont été réalisées avec une presse uniaxiale LLOYDS. Un système de chauffage et de régulation en température a été adapté sur des matrices de compression uniaxiale. Un suivi de la porosité et des émissions acoustiques en cours de compression a été réalisé. Les relations de ces caractéristiques avec les mesures de la résistance à la rupture et l'évolution des microstructures des comprimés obtenus sont discutées

Metasequoia glyptostroboïdes : renseignements spécifiques et bouturage

Metasequoia glyptostroboïdes est présenté à travers ses particularités spécifiques, qui pourraient être exploitées en sylviculture intensive. L'expansion de l'essence est actuellement conditionnée par le bouturage dont certaines modalités ont été étudiées. Ainsi, le choix des boutures, en fonction de critères morphologiques et architecturaux, est très influent. Les rameaux caducs sont à proscrire, périclitant après repiquage en dépit de leur enracinement. D'autre part, l'aptitude à la rhizogenèse est corrélée avec la position des ramets au sein de l'ortet, en fonction de gradients de niveaux de branchaison et de prélèvement intraraméal. L'intérêt du bouturage herbacé ou ligneux est discuté. La technique du bouturage, à partir de pieds-mères, est comparée au bouturage en cascade d'un point de vue plus synthétique. (Résumé d'auteur

Influence of temperature on the compaction and the mechanical strength of an organicpowder

6 pagesClassical works made on powder compaction have been developing studies of parameters like the maximum pressure reached, the punch velocity, the duration of isobaric stage, on tablets properties. But the influence of temperature during the compression has been neglected in most cases. Now, most of pharmaceutical and chemical products, in particular organic products, are sensitive to temperature. In this work, the role of temperature on the compressibility of an organic powder commonly used in the industry has been examined. The consequences on the structure and on the mechanical behaviour of the tablets have been studied. The evolution of the porosity, the tablet strength and the fracture aspects have been followed and then analysed during and after the compression

A Compilation Flow for Parametric Dataflow: Programming Model, Scheduling, and Application to Heterogeneous MPSoC

International audienceEfficient programming of signal processing applications on embedded systems is a complex problem. High level models such as Synchronous dataflow (SDF) have been privileged candidates for dealing with this complexity. These models permit to express inherent application parallelism, as well as analysis for both verification and optimization. Parametric dataflow models aim at providing sufficient dynamicity to model new applications, while at the same time maintaining the high level of analyzability needed for efficient real life implementations. This paper presents a new compilation flow that targets parametric dataflows. Built on the LLVM compiler infrastructure, it offers an actor based C++ programming model to describe parametric graphs, a compilation front-end providing graph analysis features, and a retargetable back-end to map the application on real hardware. This paper gives an overview of this flow, with a specific focus on scheduling. The crucial gap between dataflow models and real hardware on which actor firing is not atomic, as well as the consequences on FIFOs sizing and execution pipelining are taken into account.The experimental results illustrate our compilation flow applied to compilation of 3GPP LTE-Advanced demodulation on a heterogeneous MPSoC with distributed scheduling features. This achieves performances similar to time-consuming hand made optimizations

Par4All: From Convex Array Regions to Heterogeneous Computing

2 pagesInternational audienceRecent compilers comprise an incremental way for converting software toward accelerators. For instance, the pgi Accelerator [14] or hmpp [3] require the use of directives. The programmer must select the pieces of source that are to be executed on the accelerator, providing optional directives that act as hints for data allocations and transfers. The compiler generates all code automatically. [...] Unlike these approaches, Par4All [13] is an automatic parallelizing and optimizing compiler for C and Fortran sequential programs funded by the hpc Project startup. The purpose of this source-to-source compiler is to integrate several compilation tools into an easy-to-use yet powerful compiler that automatically transforms existing programs to target various hardware platforms

To respond or not to respond - a personal perspective of intestinal tolerance

For many years, the intestine was one of the poor relations of the immunology world, being a realm inhabited mostly by specialists and those interested in unusual phenomena. However, this has changed dramatically in recent years with the realization of how important the microbiota is in shaping immune function throughout the body, and almost every major immunology institution now includes the intestine as an area of interest. One of the most important aspects of the intestinal immune system is how it discriminates carefully between harmless and harmful antigens, in particular, its ability to generate active tolerance to materials such as commensal bacteria and food proteins. This phenomenon has been recognized for more than 100 years, and it is essential for preventing inflammatory disease in the intestine, but its basis remains enigmatic. Here, I discuss the progress that has been made in understanding oral tolerance during my 40 years in the field and highlight the topics that will be the focus of future research

Analyse descriptive du traitement médicamenteux chez des patients hospitalisés pour décompensation cardiaque au CHU de Grenoble

Malgré une évolution des connaissances sur le traitement de l insuffisance cardiaque au cours de ces dernières années, une forte proportion de patients ne sont pas toujours traités de manière optimale. L European Society of Cardiology a publié en 2012 les dernières recommandations visant à améliorer la prise en charge de cette pathologie chronique et fréquente (prévalence entre 1 et 2% de la population adulte, plus de 10% chez les personnes de 70 ans ou plus). Au cours de cette étude, les prescriptions de 50 patients hospitalisés au CHU de Grenoble pour décompensation cardiaque sont analysées et comparées à ces recommandations dans le but d en étudier les éventuelles discordances.Despite the improvement of the treatment for heart failure over last years, a large part of patients are not still treated on an optimal way. The European Society of Cardiology (ESC) has published guidelines on chronic heart failure in 2012. The prevalence of this disease is very high, 1-2 % of the adult population having chronic heart failure and more than 10% of subjects aged of 70 years or more having this disease. The aim of the present study was to analyze the medical prescription for heart failure in patients hospitalized at the Grenoble University Hospital for heart failure. Data were compared to those recommended by the ESC in order to determine and explain potential discrepancies.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF