68 research outputs found
Constructions for Clumps Statistics.
International audienceWe consider a component of the word statistics known as clump; starting from a finite set of words, clumps are maximal overlapping sets of these occurrences. This object has first been studied by Schbath with the aim of counting the number of occurrences of words in random texts. Later work with similar probabilistic approach used the Chen-Stein approximation for a compound Poisson distribution, where the number of clumps follows a law close to Poisson. Presently there is no combinatorial counterpart to this approach, and we fill the gap here. We also provide a construction for the yet unsolved problem of clumps of an arbitrary finite set of words. In contrast with the probabilistic approach which only provides asymptotic results, the combinatorial method provides exact results that are useful when considering short sequences
Constructions for Clumps Statistics.
We consider a component of the word statistics known as clump; starting from a finite set of words, clumps are maximal overlapping sets of these occurrences. This object has first been studied by Schbath with the aim of counting the number of occurrences of words in random texts. Later work with similar probabilistic approach used the Chen-Stein approximation for a compound Poisson distribution, where the number of clumps follows a law close to Poisson. Presently there is no combinatorial counterpart to this approach, and we fill the gap here. We also provide a construction for the yet unsolved problem of clumps of an arbitrary finite set of words. In contrast with the probabilistic approach which only provides asymptotic results, the combinatorial method provides exact results that are useful when considering short sequences
Automates lexico-phonétiques pour l'indexation et la recherche de segments de parole
National audienceThis paper presents a method for indexing spoken utterances which combines lexical and phonetic hypotheses in a hybrid index built from automata. The retrieval is realized by a lexical-phonetic and semi-imperfect matching whose aim is to improve the recall. A feature vector, containing edit distance scores and a confidence measure, weights each transition to help the filtering of the candidate utterance list for a more precise search. Experiment results show that the lexical and phonetic representations are complementary and we compare the hybrid search with the state-of-the-art cascaded search to retrieve named entity queries.Ce papier1 présente une méthode d'indexation de segments de parole qui combine des hypothèses lexicales et phonétiques au sein d'un index hybride à base d'automates. La recherche se fait via un appariement lexico-phonétique semi-imparfait qui tolère certaines imperfections pour améliorer le rappel. Un vecteur de descripteurs, contenant des scores d'édition et une mesure de confiance, pondère chaque transition permettant de caractériser la pertinence des segments candidats pour une recherche plus précise. Les expériences montrent la complémentarité des représentations lexicales et phonétiques et leur intérêt pour rechercher des requêtes d'entités nommées
In vitro antibacterial activity of dinuclear thiolato-bridged ruthenium(II)-arene compounds.
The antibacterial activity of 22 thiolato-bridged dinuclear ruthenium(II)-arene compounds was assessed in vitro against Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus. None of the compounds efficiently inhibited the growth of the three E. coli strains tested, and only compound 5 exhibited a medium activity against this bacterium [MIC (minimum inhibitory concentration) of 25 µM]. However, a significant antibacterial activity was observed against S. pneumoniae, with MIC values ranging from 1.3 to 2.6 µM for compounds 1-3, 5, and 6. Similarly, compounds 2, 5-7, and 20-22 had MIC values ranging from 2.5 to 5 µM against S. aureus. The tested diruthenium compounds have a bactericidal effect significantly faster than that of penicillin. Fluorescence microscopy assays performed on S. aureus using the BODIPY-tagged diruthenium complex 15 showed that this type of metal compound enters the bacteria and does not accumulate in the cell wall of gram-positive bacteria. Cellular internalization was further confirmed by inductively coupled plasma mass spectrometry experiments. The nature of the substituents anchored on the bridging thiols and the compounds molecular weight appears to significantly influence the antibacterial activity. Thus, if overall a decrease of the bactericidal effect with the increase of compounds' molecular weight is observed, however, the complexes bearing larger benzo-fused lactam substituents had low MIC values. This first antibacterial activity screening demonstrated that the thiolato-diruthenium compounds exhibit promising activity against S. aureus and S. pneumoniae and deserve to be considered for further studies. IMPORTANCE The in vitro assessment of diruthenium(II)-arene compounds against Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus showed a significant antibacterial activity of some compounds against S. pneumoniae, with minimum inhibitory concentration (MIC) values ranging from 1.3 to 2.6 µM, and a medium activity against E. coli, with MIC of 25 µM. The nature of the substituents anchored on the bridging thiols and the compounds molecular weight appear to significantly influence the antibacterial activity. Fluorescence microscopy showed that these ruthenium compounds enter the bacteria and do not accumulate in the cell wall of gram-positive bacteria. These diruthenium(II)-arene compounds exhibit promising activity against S. aureus and S. pneumoniae and deserve to be considered for further studies, especially the compounds bearing larger benzo-fused lactam substituents
Success of passive and active restoration of lowland hay meadows with regard to current and historical references
The restoration of hay meadows is one of the major challenges in temperate Europe, to overcome the drastic loss and degradation of these semi-natural habitats. Evaluation of restoration success requires the definition of a relevant reference ecosystem. Historical phytosociological relevés dating from the 1960s–1970s, before large scale agriculture intensification, may be used as the reference framework for such purposes. However, this reference framework may no longer be pertinent in our present-day ecological and socio-economic context. In this study, we assessed the success of three restoration techniques for lowland hay meadows, based on plant species richness and composition and functional traits, by comparing the restoration trajectories to historical and current references. The three restoration techniques, passive restoration mowing, active fresh hay transfer and active sowing of threshing material, were implemented depending on the initial level of degradation and the proximity to well-preserved meadows. The species composition of restored meadows clearly differed from historical references but converged toward current references, for both passive and active restoration techniques. Historical references are characterized by short, stress-tolerant dicotyledonous plant species with small specific leaf area, indicators of nutrient-poor environments. The gap observed between plant communities of historical and current meadows suggests that the historical data are an over-ambitious target for restoration purposes and can hardly be considered relevant to our present-day context. Therefore, creation of a new reference framework of lowland hay meadows is needed for the adequate implementation of restoration projects. Successful outcomes of active and passive techniques must encourage practitioners to adapt the choice of the restoration method depending on the local ecological context, i.e., level of degradation and proximity to well-preserved habitats
DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France
We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon
Entrepreneurial identity formation during the initial entrepreneurial experience: The influence of simulation feedback and existing identity
© 2017 Elsevier Inc. The impact of a negative initial entrepreneurship experience may inhibit the emergence of an entrepreneurial identity and shut down a subsequent entrepreneurial career. Testing theories of identity development usually involve complex longitudinal studies, but the testing may be facilitated through the use of business simulation gaming. Using a quasi-experimental research design, the paper explores how entrepreneurial micro-identity is formed among business undergraduates during the initial entrepreneurial experience. In doing so, the research investigates the impact of cognitive dissonance on the salience of the emerging identity and the influence of key existing identities. The paper accomplishes this using a novel dataset derived from a business simulation game. We argue that the simulation offers a valuable resource to test theories within shortened timescales. The paper contributes to the field by problematizing the initial entrepreneurial experience of undergraduate students and supports the case for using simulation gaming as a method to support theory testing
Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.
RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Quality of Experience in 3D Multimedia
International audienceThe Quality of Experience (QoE) is a key element in the search for rapid growth of three-dimensional video technology. Research concerning the study of QoE in a 3D environment is on the move. This paper proposes a review of 3D QoE specificities. We will also present the actual findings in this area as well as the projects in process around the world. Thus, any researcher wishing to know more about this domain will be able to start with the foundations necessary to understand the issues related to 3D
- …