Bacteriophages display remarkable genetic diversity and host specificity. In this study, we explore phages infecting bacterial strains of the Enterobacteriaceae family because of their ability to ...infect related but distinct hosts. We isolated and characterized two novel virulent phages, SH6 and SH7, using a strain of Shigella flexneri as host bacterium. Morphological and genomic analyses revealed that phage SH6 belongs to the T1virus genus of the Siphoviridae family. Conversely, phage SH7 was classified in the T4virus genus of the Myoviridae family. Phage SH6 had a short latent period of 16 min and a burst size of 103 ± 16 PFU/infected cell while the phage SH7 latent period was 23 min with a much lower burst size of 26 ± 5 PFU/infected cell. Moreover, phage SH6 was sensitive to acidic conditions (pH < 5) while phage SH7 was stable from pH 3 to 11 for 1 hour. Of the 35 bacterial strains tested, SH6 infected its S. flexneri host strain and 8 strains of E. coli. Phage SH7 lysed additionally strains of E. coli O157:H7, Salmonella Paratyphi, and Shigella dysenteriae. The broader host ranges of these two phages as well as their microbiological properties suggest that they may be useful for controlling bacterial populations.
Sentiment Analysis (SA) helps to automatically and meaningfully discover hotel customers’ satisfaction from their shared experiences and feelings on social media. Several studies have been conducted ...to improve the precision of SA in the hospitality industry, which vary in data preprocessing techniques, feature representation, sentiment classification levels, and models, and they use different datasets. Such variations are worthy of attention and monitoring. Despite the importance of SA in hospitality and tourism, review studies identifying gaps and suggesting future research directions are limited. This article introduces a systematic literature review to label and discuss state-of-the-art studies that deal with SA for hotel reviews.
Posting sarcastic comments on hotel opinion websites became a common trend. Therefore, sarcasm detection becomes of primary importance, mainly since sarcasm can flip the review's polarity. To our ...knowledge, no work related to detecting sarcasm exists in the hospitality industry. The lack of a labeled dataset is an utmost issue for researchers. We propose a new approach based on the domain adaptation using the self-training technique for the semi-supervised learning of sarcastic Arabic hotel reviews. We use AraBERT for contextual embedding and machine learning models for self-training classification. The obtained accuracy reaches 91.1%.
Les orages rythmiques (OR) dont des urgences cardiaques absolues grevées d'une mortalité accrue à court terme. La véritable incidence des orages rythmiques chez les patients porteurs de ...défibrillateurs automatiques implantables (DAI) est difficile à estimer en raison de la définition hétérogène. La présentation clinique est variable et la prise en charge est multidisciplinaire.
L'objectif de l’étude est d'analyser le profil épidémiologique ainsi que l’évolution d'un groupe de patients implantés d'un DAI ayant eu des orages rythmiques détectés par la télécardiologie.
Il s'agit d'une étude observationnelle rétrospective monocentrique qui a inclus 14 patients implantés d'un DAI entre 2008 et 2021 en prévention primaire ou secondaire et suivis en télécardiologie. Tous ces patients ont eu au moins un orage rythmique détecté par la télécardiologie et authentifié par un ECG de surface.
L’âge moyen des patients au moment de survenue de l'orage rythmique était de 75,4 ± 14,5 ans avec des extrêmes allant de 49 à 101 ans. La plupart des patients (n = 11) étaient de sexe masculin. La cardiopathie ischémique était retrouvée dans la majorité des cas (n = 12). Un tiers des cas était implanté en prévention secondaire. L'orage rythmique était en rapport avec des épisodes récurrents de tachycardie ventriculaire. Aucun cas de fibrillation ventriculaire n'a été détecté. La syncope représentait la présentation clinique la plus fréquente (quatre patients). Neuf patients ont reçu des chocs internes avec un nombre moyen de quatre chocs par patient. Le facteur déclenchant était une ischémie myocardique chez quatre patients. La plupart des patients ont été pris en charge en soins intensifs cardiologiques et deux parmi eux ont été hospitalisés en réanimation.
En plus du traitement anti-arythmique par amiodarone et bêtabloquant, Neuf patients ont bénéficié d'une ablation des foyers de tachycardies ventriculaires.
La mortalité était élevée (dans la moitié des cas) en rapport avec un état de choc cardiogénique majoritairement.
Cette étude montre que les OR restent rares mais qu'ils restent associés à une mortalité élevée. La télécardiologie permet de les prendre en charge plus précocement.
Electrical storms (ES) are serious cardiac emergencies associated with increased short-term mortality. The true incidence of ES in patients with an implantable cardioverter defibrillator (ICD) is still difficult to estimate because of the heterogeneous definition. The clinical presentation is variable and its management is multidisciplinary.
The aim of the study was to analyze the epidemiological profile and evolution of a group of patients implanted with an ICD who had electrical storms detected by a home monitoring system.
This is a single-center retrospective observational study, which included 14 patients who were implanted with ICDs, for primary or secondary prevention between 2008 and 2021. All of them were followed by home monitoring. All these patients had an ES detected by home monitoring and authenticated by ECG.
The mean age of the patients at the time of onset of the electrical storm was 75.4 ± 14.5 years, with extremes ranging from 49 to 101 years. Most of patients (n = 11) were male. The majority of them had underlying ischaemic cardiomyopathy (n = 12). In a third of cases (n = 5) patients were implanted for secondary prevention. The electrical storm was related to recurrent episodes of VT. No cases of VF were detected. Syncope was the most frequent clinical presentation (four patients). Nine patients received internal shocks, with an average of four shocks per patient. The triggering factor was myocardial ischaemia in four cases. Majority of patients were managed in the cardiac intensive care unit. Two patients were admitted to the intensive care unit. In addition to anti-arrhythmic treatment with amiodarone and beta blockers. Nine patients underwent ablation of ventricular tachycardia focus. Mortality was high (in half of the cases) mainly due to a cardiogenic shock.
This study shows that OR remain rare, but are still associated with high mortality. Home monitoring makes it possible to manage them earlier.
In many fields, like aspect category detection (ACD) in aspect‐based sentiment analysis, it is necessary to label each instance with more than one label at the same time. This study tackles the ...multilabel classification problem in the ACD task for the Arabic language. For this purpose, we used Arabic hotel reviews from the SemEval‐2016 dataset, comprising 13,113 annotated tuples provided for training (10,509) and testing (2,604). To extract valuable information, we first propose specific data preprocessing. Then, we suggest using the dynamic weighted loss function and a data augmentation method to fix the problem with this dataset's imbalance. Using two possible approaches, we develop new ways to find different categories of things in a review sentence. The first is based on classifier chains using machine learning models. The second is based on transfer learning using pretrained AraBERT fine‐tuning for contextual representation. Our findings show that both approaches outperformed the related works for ACD on the Arabic SemEval‐2016. Moreover, we observed that AraBERT fine‐tuning performed much better and achieved a promising F1$$ {F}_1 $$‐score of 68.02%$$ 68.02\% $$.
Trust systems represent a significant trend in decision support for social networks’ service provision. The basic idea is to allow users to rate each other even without being direct neighbours. In ...this case, the purpose is to derive a trust score for a given user, which could be of help to decide whether to trust other users or not. In this article, we investigate the properties of trust propagation within social networks, based on the notion of
transitivity
, and we introduce the
TISoN
model to generate and evaluate
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rust
I
nference within online
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cial
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etworks. To do so, (
i
) we develop a novel
TPS
algorithm for
T
rust
P
ath
S
earching where we define neighbours’ priority based on their direct trust degrees, and then select trusted paths while controlling the path length; and, (
ii
) we develop different
TIM
algorithms for
T
rust
I
nference
M
easuring and build a trust network. In addition, we analyse existing algorithms and we demonstrate that our proposed model better computes transitive trust values than do the existing models. We conduct extensive experiments on a real online social network dataset, Advogato. Experimental results show that our work is scalable and generates better results than do the pioneering approaches of the literature.
Citrobacter freundii causes opportunistic infections in humans and animals, which are becoming difficult to treat due to increased antibiotic resistance. The aim of this study was to explore phages ...as potential antimicrobial agents against this opportunistic pathogen. We isolated and characterized five new virulent phages, SH1, SH2, SH3, SH4, and SH5 from sewage samples in Tunisia. Morphological and genomic analyses revealed that the five C. freundii phages belong to the Caudovirales order, Podoviridae family, and Autographivirinae subfamily. Their linear double-stranded DNA genomes range from 39,158 to 39,832 bp and are terminally redundant with direct repeats between 183 and 242 bp. The five genomes share the same organization as coliphage T7. Based on genomic comparisons and on the phylogeny of the DNA polymerases, we assigned the five phages to the T7virus genus but separated them into two different groups. Phages SH1 and SH2 are very similar to previously characterized phages phiYeO3-12 and phiSG-JL2, infecting, respectively, Yersinia enterocolitica and Salmonella enterica, as well as sharing more than 80% identity with most genes of coliphage T7. Phages SH3, SH4, and SH5 are very similar to phages K1F and Dev2, infecting, respectively, Escherichia coli and Cronobacter turicensis. Several structural proteins of phages SH1, SH3, and SH4 were detected by mass spectrometry. The five phages were also stable from pH 5 to 10. No genes coding for known virulence factors or integrases were found, suggesting that the five isolated phages could be good candidates for therapeutic applications to prevent or treat C. freundii infections. In addition, this study increases our knowledge about the evolutionary relationships within the T7virus genus.
Les réseaux sociaux ont connu une évolution dramatique et ont été utilisés comme des moyens pour exercer plusieurs activités. En fait, via les réseaux sociaux, les utilisateurs peuvent découvrir, ...gérer et partager leurs expériences et avis en ligne. Cependant, la nature ouverte et décentralisée des réseaux sociaux les rend vulnérables à l'apparition des utilisateurs malveillants. Par conséquent, les utilisateurs éventuels peuvent faire face à plusieurs de problèmes liés à la confiance. Ainsi, une évaluation de confiance effective et efficace est très importante pour la prise de décisions par ces utilisateurs. En effet, elle leur fournit des informations précieuses leur permettant de faire la différence entre ceux dignes et indignes de confiance. Cette thèse a pour but de fournir des méthodes de gestion de confiance et de réputation des utilisateurs des réseaux sociaux efficaces et qui peuvent être présentées par les quatre contributions suivantes. La première contribution présente une complexe extraction des contextes et des intérêts des utilisateurs, où les informations contextuelles sociales complexes sont prises en compte, reflétant mieux les réseaux sociaux. De plus, nous proposons un enrichissement de l'ontologie Dbpedia par des concepts de folksonomies.Ensuite, nous proposons une approche de gestion de la confiance, intitulée IRIS, permettant la génération du réseau de confiance et le calcul de la confiance directe. Cette approche considère les activités sociales des utilisateurs incluant leurs relations sociales, préférences et interactions.La troisième contribution de cette thèse est la gestion de transitivité de confiance dans les réseaux sociaux. En fait, c'est nécessaire et significatif d'évaluer la confiance entre deux participants n’ayant pas des interactions directes. Nous proposons ainsi, un modèle d'inférence de confiance, appelé TISON, pour évaluer la confiance indirecte dans les réseaux sociaux.La quatrième contribution de cette thèse consiste à gérer la réputation des utilisateurs des réseaux sociaux. Pour ce faire, nous proposons deux nouveaux algorithmes. Nous présentons un nouvel algorithme exclusif pour la classification des utilisateurs basés sur leurs réputations, appelé le RePC. De plus, nous proposons un deuxième algorithme, FCR, qui présente une extension floue de RePC. Pour les approches proposées, nous avons conduits différentes expérimentations sur des ensembles de données réels ou aléatoires. Les résultats expérimentaux ont démontré que nos algorithmes proposés produisent de meilleurs résultats, en termes de qualité des résultats livrés et d’efficacité, par rapport à différentes approches introduites dans littérature
Online Social Networks (OSNs) have known a dramatic increase and they have been used as means for a rich variety of activities. In fact, within OSNs, usersare able to discover, extend, manage, and leverage their experiences and opinionsonline. However, the open and decentralized nature of the OSNs makes themvulnerable to the appearance of malicious users. Therefore, prospective users facemany problems related to trust. Thus, effective and efficient trust evaluation isvery crucial for users’ decision-making. It provides valuable information to OSNsusers, enabling them to make difference between trustworthy and untrustworthyones. This thesis aims to provide effective and efficient trust and reputationmanagement methods to evaluate trust and reputation of OSNs users, which canbe divided into the following four contributions.The first contribution presents a complex trust-oriented users’ contexts andinterests extraction, where the complex social contextual information is taken intoaccount in modelling, better reflecting the social networks in reality. In addition,we propose an enrichment of the Dbpedia ontology from conceptualizations offolksonomies.We second propose the IRIS (Interactions, Relationship types and Interest Similarity)trust management approach allowing the generation of the trust networkand the computation of direct trust. This model considers social activities of usersincluding their social relationships, preferences and interactions. The intentionhere is to form a solid basis for the reputation and indirect trust models.The third contribution of this thesis is trust inference in OSNs. In fact, it isnecessary and significant to evaluate the trust between two participants whomhave not direct interactions. We propose a trust inference model called TISON(Trust Inference in Social Networks) to evaluate Trust Inference within OSNs.The fourth contribution of this thesis consists on the reputation managementin OSNs. To manage reputation, we proposed two new algorithms. We introducea new exclusive algorithm for clustering users based on reputation, called RepC,based on trust network. In addition, we propose a second algorithm, FCR, whichis a fuzzy extension of RepC.For the proposed approaches, extensive experiments have been conducted onreal or random datasets. The experimental results have demonstrated that ourproposed algorithms generate better results, in terms of the utility of delivered results and efficiency, than do the pioneering approaches of the literature
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