Bijections for Entringer families

Andr\'e proved that the number of alternating permutations on $\{1, 2, \dots, n\}$ is equal to the Euler number $E_n$. A refinement of Andr\'e's result was given by Entringer, who proved that counting alternating permutations according to the first element gives rise to Seidel's triangle $(E_{n,k})$ for computing the Euler numbers. In a series of papers, using generating function method and induction, Poupard gave several further combinatorial interpretations for $E_{n,k}$ both in alternating permutations and increasing trees. Kuznetsov, Pak, and Postnikov have given more combinatorial interpretations of $E_{n,k}$ in the model of trees. The aim of this paper is to provide bijections between the different models for $E_{n,k}$ as well as some new interpretations. In particular, we give the first explicit one-to-one correspondence between Entringer's alternating permutation model and Poupard's increasing tree model.Comment: 19 page

Etude de la dynamique des oscillateurs à vortex par synchronisation et modulation de fréquence

Since 2004, research on radiofrequency (RF) spintronic devices has been very active, both from a fundamental point of view as well as for their potential applications as RF oscillators or spin-diodes. These devices are based on spin transfer torque (STT). In this context, I studied vortex oscillators based on ultra-low resistance magnetic tunnel junctions in which vortex dynamics is driven into a periodic motion by STT. The vortex oscillations are observed when the junction is subjected to a large dc bias current and a low in-plane field. The dc current produces both a large Oersted field which contributes to the vortex nucleation and a STT that starts the vortex oscillation. This oscillation leads to a large output power up to 20nW with a fundamental frequency around 450MHz and many harmonics.Synchronization with an external signal was then tested by adding a RF current to the dc bias current. With a large enough input power, the oscillator locks on the external source: the noise is then drastically reduced and the spectral purity of the signal significantly increases. These observations are explained by describing the system as a parametric oscillator. This model predicts, as experimentally observed, that, for a small amplitude of the RF excitation, a dynamical instability can be more easily reached when its frequency is twice the natural frequency of the oscillator than for any other frequencies.Then, I performed frequency modulation measurements by exciting the dc-biased sample with a low frequency ac-current. The power spectral density was measured as I swept the modulation frequency for various modulation powers. It appears that the description previously used to describe modulation experiments does not apply when the modulation frequency is a significant fraction of the natural frequency. The vortex response time appears to play a significant role, so that the concept of deviation sensitivity has to be introduced to explain the observations: it corresponds to the dynamical dependence of the oscillator frequency with an applied current that varies with time.Depuis 2004, les composants radiofréquence (RF) suscitent un intérêt croissant au sein de la communauté spintronique, tant du point de vue de la physique fondamentale que des applications potentielles. Ces composants ont émergé suite à la découverte du couple de transfert de spin (STT) qui permet d'exciter l'aimantation grâce à un courant électrique. Dans ce contexte, j'ai étudié des oscillateurs à vortex basés sur des jonctions tunnel magnétiques à très faible résistance dans lesquelles un vortex magnétique suit un mouvement périodique dû au STT.On observe des oscillations de ce vortex lorsque la jonction est polarisée par un large courant dc sous un faible champ planaire. En effet, le courant produit à la fois un fort champ d'Ampère, qui contribue à la nucléation du vortex, et génère le STT qui met le vortex en mouvement. Grâce à l'oscillation du vortex, ces composants émettent un signal RF d'une forte puissance (jusqu'à 20nW) avec une fréquence naturelle d'environ 450MHz.J'ai étudié la synchronisation de ces oscillateurs en injectant, en plus courant continu, une excitation RF. Lorsque ce signal d'excitation est suffisamment puissant, l'oscillateur se verrouille sur la source externe. On observe une diminution du bruit autour du pic fondamental et une augmentation de l'amplitude de celui-ci. J'explique ces observations en modélisant le système en tant qu'oscillateur paramétrique. Cette modélisation permet de décrire certains phénomènes observés expérimentalement, comme le fait qu'il est plus facile d'atteindre le régime d'instabilité dynamique quand la fréquence de l'excitation est égale à deux fois la fréquence naturelle de l'oscillateur.Ensuite, j'ai réalisé une expérience de modulation de fréquence (FM), en excitant l'échantillon avec une onde RF à basse fréquence. L'expérience consiste à mesurer la densité spectral de puissance du signal tout en balayant la fréquence de l'onde de modulation et ceci à différente puissance. Il apparait alors que la description usuelle de la FM ne puisse plus être utilisée dans notre cas, car la fréquence de modulation est trop grande par rapport à la fréquence naturelle. Cela est dû au fait que le vortex met un certain temps à répondre à une excitation. Pour expliquer mes mesures, j'ai donc dû introduire le concept de sensibilité à la déviation, qui correspond à la dépendance de la fréquence de l'oscillateur avec le courant quand celui-ci varie périodiquement

Etude de la dynamique des oscillateurs à vortex par synchronisation et modulation de fréquence

Since 2004, research on radiofrequency (RF) spintronic devices has been very active, both from a fundamental point of view as well as for their potential applications as RF oscillators or spin-diodes. These devices are based on spin transfer torque (STT). In this context, I studied vortex oscillators based on ultra-low resistance magnetic tunnel junctions in which vortex dynamics is driven into a periodic motion by STT. The vortex oscillations are observed when the junction is subjected to a large dc bias current and a low in-plane field. The dc current produces both a large Oersted field which contributes to the vortex nucleation and a STT that starts the vortex oscillation. This oscillation leads to a large output power up to 20nW with a fundamental frequency around 450MHz and many harmonics.Synchronization with an external signal was then tested by adding a RF current to the dc bias current. With a large enough input power, the oscillator locks on the external source: the noise is then drastically reduced and the spectral purity of the signal significantly increases. These observations are explained by describing the system as a parametric oscillator. This model predicts, as experimentally observed, that, for a small amplitude of the RF excitation, a dynamical instability can be more easily reached when its frequency is twice the natural frequency of the oscillator than for any other frequencies.Then, I performed frequency modulation measurements by exciting the dc-biased sample with a low frequency ac-current. The power spectral density was measured as I swept the modulation frequency for various modulation powers. It appears that the description previously used to describe modulation experiments does not apply when the modulation frequency is a significant fraction of the natural frequency. The vortex response time appears to play a significant role, so that the concept of deviation sensitivity has to be introduced to explain the observations: it corresponds to the dynamical dependence of the oscillator frequency with an applied current that varies with time.Depuis 2004, les composants radiofréquence (RF) suscitent un intérêt croissant au sein de la communauté spintronique, tant du point de vue de la physique fondamentale que des applications potentielles. Ces composants ont émergé suite à la découverte du couple de transfert de spin (STT) qui permet d'exciter l'aimantation grâce à un courant électrique. Dans ce contexte, j'ai étudié des oscillateurs à vortex basés sur des jonctions tunnel magnétiques à très faible résistance dans lesquelles un vortex magnétique suit un mouvement périodique dû au STT.On observe des oscillations de ce vortex lorsque la jonction est polarisée par un large courant dc sous un faible champ planaire. En effet, le courant produit à la fois un fort champ d'Ampère, qui contribue à la nucléation du vortex, et génère le STT qui met le vortex en mouvement. Grâce à l'oscillation du vortex, ces composants émettent un signal RF d'une forte puissance (jusqu'à 20nW) avec une fréquence naturelle d'environ 450MHz.J'ai étudié la synchronisation de ces oscillateurs en injectant, en plus courant continu, une excitation RF. Lorsque ce signal d'excitation est suffisamment puissant, l'oscillateur se verrouille sur la source externe. On observe une diminution du bruit autour du pic fondamental et une augmentation de l'amplitude de celui-ci. J'explique ces observations en modélisant le système en tant qu'oscillateur paramétrique. Cette modélisation permet de décrire certains phénomènes observés expérimentalement, comme le fait qu'il est plus facile d'atteindre le régime d'instabilité dynamique quand la fréquence de l'excitation est égale à deux fois la fréquence naturelle de l'oscillateur.Ensuite, j'ai réalisé une expérience de modulation de fréquence (FM), en excitant l'échantillon avec une onde RF à basse fréquence. L'expérience consiste à mesurer la densité spectral de puissance du signal tout en balayant la fréquence de l'onde de modulation et ceci à différente puissance. Il apparait alors que la description usuelle de la FM ne puisse plus être utilisée dans notre cas, car la fréquence de modulation est trop grande par rapport à la fréquence naturelle. Cela est dû au fait que le vortex met un certain temps à répondre à une excitation. Pour expliquer mes mesures, j'ai donc dû introduire le concept de sensibilité à la déviation, qui correspond à la dépendance de la fréquence de l'oscillateur avec le courant quand celui-ci varie périodiquement

Differential responses of the mosquito Aedes albopictus from the Indian Ocean region to two chikungunya isolates

International audienceBACKGROUND: Aedes aegypti and Aedes albopictus are both vectors of chikungunya virus (CHIKV). The two Aedes species co-exist in the Indian Ocean region and were involved in the 2005-2006 CHIKV outbreaks. In the Reunion Island, a single mutation in the viral envelope has been selected that leads to high levels of replication in Ae. albopictus, and a short extrinsic incubation period as the virus could be found in saliva as early as two days after infection. An important question is whether this variant is associated with adverse effects impacting some mosquito life-history traits such as survival and reproduction. RESULTS: We performed experimental infections using three mosquito strains of Ae. aegypti Mayotte and Ae. albopictus (Mayotte and Reunion), and two CHIKV strains (E1-226A and E1-226V). Ae. aegypti Mayotte were similarly susceptible to both viral strains, whereas Ae. albopictus Mayotte and Ae. albopictus Reunion were more susceptible to CHIKV E1-226V than to E1-226A. In terms of life-history traits measured by examining mosquito survival and reproduction, we found that: (1) differences were observed between responses of mosquito species to the two viruses, (2) CHIKV infection only affected significantly some life-history traits of Ae. albopictus Reunion and not of the other two mosquito strains, and (3) CHIKV reduced the lifespan of Ae. albopictus Reunion and shortened the time before egg laying. CONCLUSION: We demonstrated that CHIKV only reduces the survival of Ae. albopictus from the Reunion Island. By laying eggs just before death, reproduction of Ae. albopictus from the Reunion Island is not reduced since other parameters characterizing oviposition and hatching were not affected

The MediaEval 2017 Emotional Impact of Movies Task

Non peer reviewe

Abnormal cortical sensorimotor activity during “Target” sound detection in subjects with acute acoustic trauma sequelae: an fMRI study

The most common consequences of acute acoustic trauma (AAT) are hearing loss at frequencies above 3 kHz and tinnitus. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to visualize neuronal activation patterns in military adults with AAT and various tinnitus sequelae during an auditory “oddball” attention task. AAT subjects displayed overactivities principally during reflex of target sound detection, in sensorimotor areas and in emotion-related areas such as the insula, anterior cingulate and prefrontal cortex, in premotor area, in cross-modal sensory associative areas, and, interestingly, in a region of the Rolandic operculum that has recently been shown to be involved in tympanic movements due to air pressure. We propose further investigations of this brain area and fine middle ear investigations, because our results might suggest a model in which AAT tinnitus may arise as a proprioceptive illusion caused by abnormal excitability of middle-ear muscle spindles possibly link with the acoustic reflex and associated with emotional and sensorimotor disturbances

Cooperative Metaheuristics for Exploring Proteomic Data

Most combinatorial optimization problems cannotbe solved exactly. A class of methods, calledmetaheuristics, has proved its efficiency togive good approximated solutions in areasonable time. Cooperative metaheuristics area sub-set of metaheuristics, which implies aparallel exploration of the search space byseveral entities with information exchangebetween them. The importance of informationexchange in the optimization process is relatedto the building block hypothesis ofevolutionary algorithms, which is based onthese two questions: what is the pertinentinformation of a given potential solution andhow this information can be shared? Aclassification of cooperative metaheuristicsmethods depending on the nature of cooperationinvolved is presented and the specificproperties of each class, as well as a way tocombine them, is discussed. Severalimprovements in the field of metaheuristics arealso given. In particular, a method to regulatethe use of classical genetic operators and todefine new more pertinent ones is proposed,taking advantage of a building block structuredrepresentation of the explored space. Ahierarchical approach resting on multiplelevels of cooperative metaheuristics is finallypresented, leading to the definition of acomplete concerted cooperation strategy. Someapplications of these concepts to difficultproteomics problems, including automaticprotein identification, biological motifinference and multiple sequence alignment arepresented. For each application, an innovativemethod based on the cooperation concept isgiven and compared with classical approaches.In the protein identification problem, a firstlevel of cooperation using swarm intelligenceis applied to the comparison of massspectrometric data with biological sequencedatabase, followed by a genetic programmingmethod to discover an optimal scoring function.The multiple sequence alignment problem isdecomposed in three steps involving severalevolutionary processes to infer different kindof biological motifs and a concertedcooperation strategy to build the sequencealignment according to their motif conten

CamemBERT: a Tasty French Language Model

Pretrained language models are now ubiquitous in Natural Language Processing. Despite their success, most available models have either been trained on English data or on the concatenation of data in multiple languages. This makes practical use of such models --in all languages except English-- very limited. In this paper, we investigate the feasibility of training monolingual Transformer-based language models for other languages, taking French as an example and evaluating our language models on part-of-speech tagging, dependency parsing, named entity recognition and natural language inference tasks. We show that the use of web crawled data is preferable to the use of Wikipedia data. More surprisingly, we show that a relatively small web crawled dataset (4GB) leads to results that are as good as those obtained using larger datasets (130+GB). Our best performing model CamemBERT reaches or improves the state of the art in all four downstream tasks.Comment: ACL 2020 long paper. Web site: https://camembert-model.f

Acute phase inflammation is characterized by rapid changes in plasma/peritoneal fluid N-glycosylation in mice.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Murine zymosan-induced peritonitis is a widely used model for studying the molecular and cellular events responsible for the initiation, persistence and/or resolution of inflammation. Among these events, it is becoming increasingly evident that changes in glycosylation of proteins, especially in the plasma and at the site of inflammation, play an important role in the inflammatory response. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based glycosylation profiling, we investigated the qualitative and quantitative effect of zymosan-induced peritonitis on N-glycosylation in mouse plasma and peritoneal fluid. Our results show that both N-glycomes exhibit highly similar glycosylation patterns, consisting mainly of diantennary and triantennary complex type N-glycans with high levels (>95 %) of galactosylation and sialylation (mostly NeuGc) and a medium degree of core fucosylation (30 %). Moreover, MS/MS structural analysis, assisted by linkage-specific derivatization of sialic acids, revealed the presence of O-acetylated sialic acids as well as disialylated antennae ("branching sialylation") characterized by the presence of α2-6-linked NeuGc on the GlcNAc of the NeuGcα2-3-Galβ1-3-GlcNAc terminal motif. A significant decrease of (core) fucosylation together with an increase of both α2-3-linked NeuGc and "branching sialylation" were observed in N-glycomes of mice challenged with zymosan, but not in control mice injected with PBS. Importantly, substantial changes in glycosylation were already observed 12 h after induction of peritonitis, thereby demonstrating an unexpected velocity of the biological mechanisms involved.Dutch Arthritis Association (Reumafonds) LLP-24 Innovative Medicines Initiative Joint Undertaking (IMI JU)/ 115142-2 Netherlands Genomic Initiative/93511033 info:eu-repo/grantAgreement/EC/FP7/278535info:eu-repo/grantAgreement/EC/FP7/27853