83 research outputs found
Semaine d'Etude MathĂ©matiques et Entreprises 6 : Analyse statistique des deÌfauts en eÌlectronique analogique
Nous nous inteÌressons aÌ des donneÌes issues de mesures de tensions sur des circuits eÌlectroniques analogiques. Plus preÌciseÌment, il s'agit de proposer une analyse de courbes repreÌsentant l'eÌvolution en fonction du temps des tensions en diffeÌrents nĆuds d'un circuit eÌlectronique. Notre objectif est de proposer une analyse automatiseÌe de la qualiteÌ des courbes. Plus preÌciseÌment, nous proposons ici des meÌthodes statistiques d'analyse de donneÌes capable de : -- Identifier d'eÌventuels patterns dans les courbes (classification), -- Isoler les courbes preÌsentant des "anomalies" (deÌtection de courbes suspectes)
Primal-dual formulation of the Dynamic Optimal Transport using Helmholtz-Hodge decomposition
This work deals with the resolution of the dynamic optimal transport (OT) problem between 1D or 2D images in the fluid mechanics framework of Benamou-Brenier [6]. The numerical resolution of this dynamic formulation of OT, despite the successful application of proximal methods [36] is still computationally demanding. This is partly due to a space-time Laplace operator to be solved at each iteration, to project back to a divergence free space. In this paper, we develop a method using the Helmholtz-Hodge decomposition [23] in order to enforce the divergence-free constraint throughout the iterations. We prove that the functional we consider has better convexity properties on the set of constraints. In particular we explain that in 1D+time, this formulation is equivalent to the resolution of a minimal surface equation. We then adapt the first order primal-dual algorithm for convex problems of Chambolle and Pock [12] to solve this new problem, leading to an algorithm easy to implement. Besides, numerical experiments demonstrate that this algorithm is faster than state of the art methods for dynamic optimal transport [36] and efficient with real-sized images
Combination of MALDI-TOF Mass Spectrometry and Machine Learning for Rapid Antimicrobial Resistance Screening: The Case of Campylobacter spp.
While MALDI-TOF mass spectrometry (MS) is widely considered as the reference
method for the rapid and inexpensive identification of microorganisms in routine
laboratories, less attention has been addressed to its ability for detection of antimicrobial
resistance (AMR). Recently, some studies assessed its potential application together
with machine learning for the detection of AMR in clinical pathogens. The scope of
this study was to investigate MALDI-TOF MS protein mass spectra combined with
a prediction approach as an AMR screening tool for relevant foodborne pathogens,
such as Campylobacter coli and Campylobacter jejuni. A One-Health panel of 224
C. jejuni and 116 C. coli strains was phenotypically tested for seven antimicrobial
resistances, i.e., ciprofloxacin, erythromycin, tetracycline, gentamycin, kanamycin,
streptomycin, and ampicillin, independently, and were submitted, after an on- and
off-plate protein extraction, to MALDI Biotyper analysis, which yielded one average
spectra per isolate and type of extraction. Overall, high performance was observed
for classifiers detecting susceptible as well as ciprofloxacin- and tetracycline-resistant
isolates. A maximum sensitivity and a precision of 92.3 and 81.2%, respectively, were
reached. No significant prediction performance differences were observed between on and off-plate types of protein extractions. Finally, three putative AMR biomarkers for
fluoroquinolones, tetracyclines, and aminoglycosides were identified during the current
study. Combination of MALDI-TOF MS and machine learning could be an efficient and
inexpensive tool to swiftly screen certain AMR in foodborne pathogens, which may
enable a rapid initiation of a precise, targeted antibiotic treatment
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the worldâs oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the worldâs oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
IntroducciĂł al turisme sostenible mitjançant un projecte interdisciplinar en el cicle formatiu de grau superior dâagĂšncies de viatge
[cat] Estem vivint una situaciĂł dâemergĂšncia planetĂ ria marcada per greus
problemes estretament relacionats: degradaciĂł i contaminaciĂł dels
ecosistemes, de les culturals locals, esgotament de recursos, desequilibris
insostenibles, conflictes, pĂšrdua de la diversitat biolĂČgica i cultural... Per tant, Ă©s
per aixĂČ que cal assumir un compromĂs perquĂš lâeducaciĂł en general doni
molta importĂ ncia al que estĂ passat en el mĂłn, amb la finalitat de proporcionar
als alumnes de lâĂ mbit del turisme una visiĂł global dels problemes i fomentar
actituds i comportaments favorables per a lâassoliment dâun desenvolupament
sostenible .
El present treball pretĂ©n aportar propostes perquĂš lâeducaciĂł, i en el nostre cas
el cicle formatiu de grau superior dâagĂšncies de viatge, ajudi a formar futurs
professionals del sector turĂstic conscients dels problemes del sector i informats
sobre la importĂ ncia del desenvolupament sostenible del turisme i, per tant,
donar pas a professionals capacitats per millorar aquesta situaciĂł actual.
Pensem que la millor forma dâensenyar als nostre alumnes a entendre i valorar
un tema tan complex com és el turisme sostenible és mitjançant un projecte
didĂ ctic interdisciplinari, on gairebĂ© tots els mĂČduls es vegin involucrats i
tothom treballi de forma col·laborativa i transversal.
Per tant, el que pretenem amb aquest treball Ă©s explicar com desenvoluparĂem
un projecte interdisciplinari amb tema eix El turisme sostenible i que tindria com
a principal objectiu formar futurs professional compromesos amb el turisme
sostenible i els problemes del sector
Transport optimal et ondelettes : nouveaux algorithmes et applications Ă l'image
Optimal transport has an increasing number of applications, including image interpolation, which we study in this work. Yet, numerical resolution is still challenging, especially for real size images found in applications.We are interested in the Benamou and Brenier formulation, which rephrases the problem in the context of fluid mechanics by adding a time dimension.It is based on the minimization of a functional on a constraint space, containing a divergence free constraint and the existing algorithms require a projection onto the divergence-free constraint at each iteration.In this thesis, we propose to work directly in the space of constraints for the functional to minimize.Indeed, we prove that the functional we consider has better convexity properties on the set of constraints.To work in this space, we use three different divergence-free vector decompositions. The first in which we got interested is a divergence-free wavelet base. This formulation has been implemented numerically using periodic wavelets and a gradient descent, which lead to an algorithm with a slow convergence but validating the practicability of the method.First, we represented the divergence-free vector fields by their stream function, then we studied the Helmholtz-Hodge decompositions. We prove that both these representations lead to a new formulation of the problem, which in 1D + time, is equivalent to the resolution of a minimal surface equation on every level set of the potential, equipped with appropriate Dirichlet boundary conditions.We use a primal dual algorithm for convex problems developed by Chambolle and Pock, which can be easily adapted to our formulations and can be easily sped up on parallel architectures. Therefore our method will also provide a fast algorithm, simple to implement.Moreover, we show numerical experiments which demonstrate that our algorithms are faster than state of the art methods and efficient with real-sized images.Le transport optimal trouve un nombre grandissant dâapplications, dont celle qui nous intĂ©resse dans ce travail, l'interpolation dâimages. MalgrĂ© cet essor, la rĂ©solution numĂ©rique de ce transport soulĂšve des difficultĂ©s et le dĂ©veloppement dâalgorithmes efficaces reste un problĂšme d'actualitĂ©, en particulier pour des images de grande taille, comme on en trouve dans certains domaines (mĂ©tĂ©orologie,...).Nous nous intĂ©ressons dans ce travail Ă la formulation de Benamou et Brenier, qui ont placĂ© le problĂšme dans un contexte de mĂ©canique des milieux continus en ajoutant une dimension temporelle. Leur formulation consiste en la minimisation dâune fonctionnelle sur un espace des contraintes contenant une condition de divergence nulle, et les algorithmes existants utilisent une projection sur cet espace.A l'opposĂ©, dans cette thĂšse, nous dĂ©finissons et mettons en oeuvre des algorithmes travaillant directement dans cet espace.En effet, nous montrons que la fonctionnelle a de meilleures propriĂ©tĂ©s de convexitĂ© sur celui-ci.Pour travailler dans cet espace, nous considĂ©rons trois reprĂ©sentations des champs de vecteurs Ă divergence nulle. La premiĂšre est une base dâondelettes Ă divergence nulle. Cette formulation a Ă©tĂ© implĂ©mentĂ©e numĂ©riquement dans le cas des ondelettes pĂ©riodiques Ă l'aide d'une descente de gradient, menant Ă un algorithme de convergence lente mais validant la faisabilitĂ© de la mĂ©thode. La deuxiĂšme approche consiste Ă reprĂ©senter les vecteurs Ă divergence nulle par leur fonction de courant munie d'un relĂšvement des conditions au bord et la troisiĂšme Ă utiliser la dĂ©composition de Helmholtz-Hodge.Nous montrons de plus que dans le cas unidimensionnel en espace, en utilisant lâune ou l'autre de ces deux derniĂšres reprĂ©sentations, nous nous ramenons Ă la rĂ©solution dâune Ă©quation de type courbure minimale sur chaque ligne de niveau du potentiel, munie des conditions de Dirichlet appropriĂ©es.La minimisation de la fonctionnelle est alors assurĂ©e par un algorithme primal-dual pour problĂšmes convexes de Chambolle-Pock, qui peut aisĂ©ment ĂȘtre adaptĂ© Ă nos diffĂ©rentes formulations et est facilement parallĂšlisable, menant Ă une implĂ©mentation performante et simple.En outre, nous dĂ©montrons les gains significatifs de nos algorithmes par rapport Ă lâĂ©tat de lâart et leur application sur des images de taille rĂ©elle
Experimental infection model with the bivalvulid Enteromyxum leei (Myxidiidae) in the sharpsnout seabream, Diplodus puntazzo (Sparidae), and evaluation of the antiparasitic efficacy of a functional diet
An infection model for sharpsnout seabream Diplodus puntazzo (Walbaum) challenged with the myxosporean Enteromyxum leei (Diamant, Lom et Dykova, 1994), resembling the natural infection conditions, was used to evaluate the antiparasitic efficacy of a functional diet. Fish of an average weight of 12.5 ± 1.2 g were delivered either a functional (included as feed supplement at 0.3% levels) or a control extruded diet. After four weeks of administration of the experimental diets, fish were challenged with the parasites (cohabitation with infected donors; donor: recipient ratio 1: 1). The experiment was terminated four weeks after the start of the challenge. At the end of the experiment, growth and feeding (specific growth rate and feed efficiency), as well as immunological parameters (respiratory burst activity, antibacterial activities, hemoglobin concentration, anti-protease activity and ceruloplasmin activity) were measured along with cumulative mortality and total parasitic count in the gut. No significant difference was evident with regard to growth and feeding performance, mortality, gut parasitic load or immunological parameters as the parasitical challenge significantly affected both the performance of the control and functional diet fed fish. However, there was a less prominent impact on antibacterial, anti-protease and ceruloplasmin activity in fish fed with the functional diet. Overall, the present study validated the experimental cohabitation infection model and evaluated the efficacy of a functional ingredient as an antiparasitic agent, showing some potential effects on the fish immune response.This work was made possible through a
H2020-SFS-2014-2015 project entitled: ParaFishControl: Advanced Tools and Research Strategies for Parasite Control in
European farmed fish (grant agreement no: 634429)
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