Journal of Next-Generation Research 5.0
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Des instruments oubliés : les tables métrologiques du XVIIIe siècle
No full textInternational audienceAu XVIIIe siècle, les systèmes de mesure (longueurs, poids, capacités, monnaies) sont complexes. De plus, ils varient d'un pays à l'autre, d'une région à l'autre, d'une ville à l'autre, d'une corporation à l'autre. Cela entraine des calculs compliqués dans la vie quotidienne, des erreurs fréquentes et de multiples possibilités de fraude. Alors que les mathématiques savantes sont en plein essor en Europe, avec notamment le développement du calcul différentiel et intégral, les mathématiques du quotidien restent fortement handicapées par une métrologie archaïque, faite d'unités disparates et de subdivisions irrégulières. Tous les calculs sont rendus épuisants par les systèmes non décimaux utilisés pour les diverses grandeurs. Seule l'addition est une opération relativement facile à exécuter. La multiplication et la division sont des cauchemars pour les banquiers, les négociants, les notaires, qui doivent calculer des intérêts, des rentes, des partages. Et les tables de logarithmes, certes utiles aux astronomes ou aux mathématiciens, sont inopérantes pour des multiplications dans des systèmes non décimaux. Face à cette situation inconfortable, diverses tentatives ont été faites à la fin du XVIIe siècle et au XVIIIe siècle pour simplifier les calculs monétaires et métrologiques. Nous allons voir comment plusieurs sortes de tables – numériques ou graphiques – ont été conçues à ce moment-là pour faciliter la vie des citoyens, en particulier des gens peu instruits en arithmétique qui étaient naturellement les premiers à rencontrer de grandes difficultés de calcul, y compris dans les opérations monétaires et métrologiques les plus banales
Artificial daily fluctuations of river discharge affect the larval drift and survival of a tropical amphidromous goby
No full text[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiplesInternational audienceAmphidromous fish species reproduce in rivers, and their larvae immediately drift to the sea after hatching. Most of these larvae survive in freshwater for a few days only, rapidly reaching sea water is thus essential. Being of small size, especially among species of the Sicydiinae subfamily, the larvae possess poor swimming abilities; their drift dynamics is considered to be mainly passive and influenced by flow conditions. The influence of daily fluctuations in flow regime on Sicyopterus lagocephalus (Sicydiinae) larval drift patterns was studied using drift nets at three sites along the dammed Langevin River in Reunion Island. The river flow was stable at the upstream site when frequent anthropogenic river flow fluctuations were observed at the two sites downstream to the dam. Weak diel larval drift dynamics were detected at the upstream site and the first site under anthropogenic river flow conditions. In contrast, larval drift dynamics at the most downstream site was strongly influenced by anthropogenic daily fluctuations of discharge: the abundance of drifting larvae increased with peaks of discharge, regardless of the time. As higher mortality rates of drifting larvae were observed during discharge peaks, the benefit of a more rapid travel to the ocean associated with these peaks should be lower than expected. It is concluded that peaks of discharge increase the number of larvae drifting to the sea probably due to higher physical constraints on the egg clutches, but also decrease the chance of survival for larvae that may be nonfully developed
Theoretical assessment of the impact of climatic factors in a vibrio cholerae model
No full textInternational audienceA mathematical model for Vibrio Cholerae (V. Cholerae) in a closed environment is considered, with the aim of investigating the impact of climatic factors which exerts a direct influence on the bacterial metabolism and on the bacterial reservoir capacity. We first propose a V. Cholerae mathematical model in a closed environment. A sensitivity analysis using the eFast method was performed to show the most important parameters of the model. After, we extend this V. cholerae model by taking account climatic factors that influence the bacterial reservoir capacity. We present the theoretical analysis of the model. More precisely, wecompute equilib-ria and study their stabilities. The stability of equilibria was investigated using the theory of periodic cooperative systems with a concave nonlinearity. Theoretical results are supported by numerical simulations which further suggest the necessity to implement sanitation campaigns of aquatic environments by using suitable prod-ucts against the bacteria during the periods ofgrowth of aquatic reservoirs
Meteoric diagenesis and dedolomite fabrics in precursor primary dolomicrite in a mixed carbonate-evaporite system
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Improving the Heliosat-2 method for surface solar irradiation estimation under cloudy sky areas
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On Two Possible Ways to Improve Computational Efficiency in Full Waveform Tomography based on Numerical Solvers
No full textInternational audienceThe advent of accurate numerical computations of the seismic wavefield in complex 3D earth models, and among them the popular spectral element method (SEM), has opened new perspectives for full waveform mantle tomography, in particular at continental and global scales. Yet, some challenges remain, such as the computational time required to build a high resolution model including teleseismic waveform data at high enough frequencies, given the need to perform many iterations to achieve convergence of this type of non-linear problem.Here I discuss and illustrate two potential avenues for improving the efficiency of the tomographic process based on numerical wavefield computations. The first one is the concept of “box tomography”, in which a target remote region of the mantle is considered and the teleseismic wavefield is computed only once for each external source in a reference, fixed, global 3D model, using any global solver. Any subsequent iterations of the model are performed only within the target region, seamlessly connecting the wavefield outside and inside the box through the introduction of time reversal mirrors (e.g. Masson and Romanowicz, 2017). This approach was already implemented in the case of receivers located within the box (Clouzet et al., 2018) and recently extended to the general case of stations and sources located within or outside the box (e.g. Adourian et al., Fall AGU 2018).The second approach is based on source stacking (e.g. Capdeville et al., 2005). By aligning a set of sources in time and computing the resulting summed wavefield only once, it allows the reduction of computational time by several orders of magnitude. The perceived drawback is the loss of achievable resolution, because the summed wavefield is dominated by large amplitude fundamental mode surface waves that cannot be windowed and weighted as in conventional waveform tomography. However, by applying cross-correlation to the stacked wavefield at available pairs of stations, we have shown that, even while the Green’s function is incompletely reconstructed, the large amplitude surface wave energy can be isolated and weighted down to bring out the contribution of body waves and overtones (e.g. Romanowicz, et al., 2013). I illustrate the first application of this method to real data and discuss possible ways to handle missing records
Macroalgae as a tool for assessing the ecological status of coral reefs under the Water Framework Directive: A case study on the reef flats of La Reunion (Indian Ocean)
No full textInternational audienceThe monitoring of macroalgae is required by the Water Framework Directive (WFD) to achieve good ecological status for coastal waters and specific questions arise for tropical ecosystems belonging to the outermost European regions. To assess the suitability of macroalgae as a biological quality indicator for La Reunion reef flats (France), we performed multivariate analyses linking the abundance and composition of macroalgae to water physicochemistry. Three hydrological groups of stations were identified according to dissolved inorganic nitrogen (DIN) concentrations and DIN/PO4 ratios. Some indicator species were found at the N-enriched stations (Bryopsis pennata, Caulerpa lamourowcii, Chaetomoropha vieillardii, Derbesia sp1, Blennothrix lyngbyacea, Sphacelaria tribubides), and others at the non-impacted stations (Anabaena sp1, Blennothrix glutinosa, Codium arabicum, Neomeris vanbosseae). Another key result was the significant increase in red algal cover at the most N-enriched station. Our findings are discussed in the context of the application of the WFD in the outermost French regions
CHAPITRE 4. L'exploitation des ressources génétiques marines au-delà des juridictions : vers un nouvel horizon ?
No full textInternational audienceAbstract: It appears today that few rules govern the exploitation of marine genetic resources in areas beyond national jurisdiction. This situation is clear both in the high seas and in the international seabed areas, where there are significant insufficiencies. This current state of law unacceptable for many reasons and it highlights the need for a new legal status for these marine genetic resources
Outbreak of IMI-1 carbapenemase-producing colistin-resistant Enterobacter cloacae on the French island of Mayotte (Indian Ocean)
No full textInternational audienceThe spread of carbapenemase-producing Enterobacteriaceae in the Southwest Indian Ocean islands is poorly known. Here we describe an outbreak of colistin-resistant Enterobacter cloacae harbouring blaIMI-1 in the French overseas department of Mayotte. Between October 2015 and January 2017, all isolates of imipenem-non-susceptible E. cloacae at Mayotte Medical Center and University Hospital of Reunion Island were screened for carbapenemase production. Positive isolates were typed by pulsed-field gel electrophoresis and whole-genome sequencing (WGS)-based multilocus sequence typing (MLST), and all β-lactamase genes were identified by PCR and sequencing. Resistance profiles were determined by agar diffusion and Etest. Genetic support of the blaIMI-1 gene was determined by WGS. A total of 18 E. cloacae isolates harbouring blaIMI-1 were detected in 17 patients from Mayotte. Pulsed-field gel electrophoresis (PFGE) analysis showed 16 of the 18 strains to be clonally related and belonging to ST820. Based on clinical data, this outbreak most likely had a community origin. The blaIMI-1 gene in the 18 isolates was carried by a new variant of an integrative mobile element involving the Xer recombinases, called EcloIMEX-8. The mcr-1-mcr-5 genes were absent from the collection. The isolates belonged to E. cloacae cluster XI, known to be colistin heteroresistant. Here we report the first outbreak of IMI-1-producing Enterobacteriaceae. IMI-1-producers may be underdetected in microbiology laboratories because of their unusual antimicrobial resistance profile (resistant to imipenem but with intermediate resistance to ertapenem and susceptible to extended-spectrum cephalosporins) and the absence of blaIMI-1 in the panel of genes targeted by molecular diagnostic kits
Joroterapia. Soigner avec la quête de sens
No full textThis research analyses a practice, born from diseases that didn’t find any answers in the biomedical field. It notices that the lack of sense or a very pejorative sense attributed to the disease results in an inner disorder which is likened to « chaos ». This void of our origins has been the roots of cosmogonic myths and ancient religions which constitute the first tidying of the world in all human civilizations. Death, the biggest disorder of human history, and any situation likened to it, bring back inside each individual this chaos and the anguish of self nihilation that is indivisible from it, through the disruption of its bonds. This is what is expressed in the psychosomatic demonstrations and the « supernatural » diseases. The tidying proposed in this practice leans on the human being, individual of bond and symbolism, which needs to be re-established individually and collectively speaking. It draws its inspiration from Malagasy culture and from its connection with the ancestors. This thesis aims to contribute to fill the breach between the scientific culture and the humanities’ one by giving birth to a boundary discipline: anthropomedicine.Cette recherche analyse une pratique, née de maladies qui n’ont pas trouvé de réponse dans le domaine biomédical. Elle constate que le manque de sens ou un sens très péjoratif à la maladie induit un désordre intérieur qui est assimilé au « chaos ». Ce néant de nos origines a été à l’origine des mythes cosmogoniques et des religions antiques qui constituent la première mise en ordre du monde dans toutes les civilisations humaines. La mort, le plus grand désordre du parcours humain, et tout ce qui lui est assimilé comme situation, ramènent en chaque individu ce chaos et l’angoisse de néantification qui lui est indissociable, à travers la perturbation de ses liens. C’est ce qui s’exprime dans les manifestations psychosomatiques et les maladies « surnaturelles ». La remise en ordre proposée dans cette pratique s’appuie sur l’humain, être de lien et de symbole, qu’il faut rétablir à la fois sur le plan individuel et collectif. Elle s’inspire de la culture malgache et de son rapport aux ancêtres. Cette thèse veut contribuer à combler la rupture entre la culture scientifique et celle des humanités par la naissance d’une discipline frontière : l’anthropomédecine