Rotavirus Strain Diversity in the Centre Coast of Tunisia from 2000 through 2003

An epidemiological survey investigating rotavirus infection in children was undertaken in the coastal region of Tunisia from January 2000 through September 2003. A total of 309 fecal specimens were screened by enzyme-linked immunosorbent assay and latex agglutination assay for the presence of group A rotavirus antigen. The detection rate was 26.2%. Rotavirus outbreaks showed a temperature-dependant pattern (P= .026) but no significant association with rainfall. Rotavirus strains isolated were analyzed by RNA polyacrylamide gel electrophoresis and were characterized antigenically by monoclonal antibodies to the VP6 subgroup. Eight RNA electropherotypes were identified, with 3 long and 5 short different RNA profiles. Among VP6 typeable strains, all isolates with a long electrophoretic pattern carried the subgroup II specificity, whereas those with a short profile belonged to subgroup I. In total, 48 rotavirus-positive samples were analyzed for G and P typing by reverse-transcription polymerase chain reaction. A total of 8 different G and P combinations were found: G1P[8] (35.7%), G1P[6] (21.4%), G2P[4] (4.8%), G3P[4] (4.8%), G4P[6] (4.8%), G8P[8] (4.8%), G3P[8] (2.3%), and G4P[8] (2.3%). Mixed infections were detected in 19.1% of stool samples. The emergence in Tunisia of unconventional types, such as G8VP7 specificity, highlights the need for a continual survey of the uncommon strains in North Afric

Genetic diversity of porcine group A rotavirus strains in the UK

Rotavirus is endemic in pig farms where it causes a loss in production. This study is the first to characterise porcine rotavirus circulating in UK pigs. Samples from diarrheic pigs with rotavirus enteritis obtained between 2010 and 2012 were genotyped in order to determine the diversity of group A rotavirus (GARV) in UK pigs. A wide range of rotavirus genotypes were identified in UK pigs: six G types (VP7); G2, G3, G4, G5, G9 and G11 and six P types (VP4); P[6], P[7], P[8], P[13], P[23], and P[32]. With the exception of a single P[8] isolate, there was less than 95% nucleotide identity between sequences from this study and any available rotavirus sequences. The G9 and P[6] genotypes are capable of infecting both humans and pigs, but showed no species cross-over within the UK as they were shown to be genetically distinct, which suggested zoonotic transmission is rare within the UK. We identified the P[8] genotype in one isolate, this genotype is almost exclusively found in humans. The P[8] was linked to a human Irish rotavirus isolate in the same year. The discovery of human genotype P[8] rotavirus in a UK pig confirms this common human genotype can infect pigs and also highlights the necessity of surveillance of porcine rotavirus genotypes to safeguard human as well as porcine health

The macroeconomic and financial determinants of the efficiency of banking in emerging countries : the case of Tunisia

Notre objectif de ce travail est d’étudier l’efficience du marché financier tunisien avant et après la révolution de Jasmin de 2011 et de déterminer les facteurs macroéconomiques et financiers qui influencent le score d’efficience de ce marché. Notre méthodologie consiste à utiliser dans un premier temps le modèle GARCH multivarié pour estimer le coefficient de corrélation entre les rendements du marché et ceux des différentes banques et le coefficient Béta. Comme ce modèle suppose des résidus qui suivent la loi normale multivariée qui est une hypothèse non vérifiée dans la pratique, nous allons utiliser dans un deuxième temps la théorie des copules pour donner une plus grande souplesse dans la modélisation des données multivariées. Les facteurs les plus influents sont déterminés en utilisant le modèle de régression linéaire,le modèle de données de Panel et le modèle TOBIT. Les résultats empiriques montrent que le marché tunisien n’est pas efficient ni avant ni après la révolution. Beaucoup d’actions sont proposées pour améliorer le degré d’efficience de ce marché.Our objective of this work is to study the efficiency of the Tunisian financial market before and after the Jasmin revolution of 2011 and identify macro-economic and financial factors that influence the efficiency score of this market. Our methodology is to use at first multivariate GARCH model to estimate the correlation between market returns and those of individual banks and the Beta coefficient. As this model assumes the residues that follow the multivariate normal law is untested in practice, we used in a second step the copula theory to provide more flexibility in modeling multivariate data. The most influential factors are determined using the linear regression model, the panel data model and TOBIT model. The empirical results show that the Tunisian market is not efficient either before or after the revolution. Many actions are proposed to improve the degree of efficiency of this market

Calculs pour les méthodes d'accès multiples dans les réseaux sans fils

Les futures générations de réseaux sans fil posent beaucoup de défis pour la communauté de recherche. Notamment, ces réseaux doivent être en mesure de répondre, avec une certaine qualité de service, aux demandes d'un nombre important de personnes et d'objets connectés. Ce qui se traduit par des exigences assez importantes en termes de capacité. C'est dans ce cadre que les méthodes d'accès multiple non orthogonaux (NOMA) ont été introduit. Dans cette thèse, nous avons étudié et proposé une méthodes d'accès multiple basé sur la technique compute and forawrd et sur les réseaux de point (Lattice codes) tout en considérant différentes constructions de lattice. Nous avons également proposé des amélioration de l'algorithme de décodage de la méthode SCMA (Sparse code multiple access) basé sur les réseaux de points. Afin de simplifier les décodeurs multi-niveaux utilisés, nous avons proposé des expressions simplifiées de LLRs ainsi que des approximations. Finalement, nous avons étudié la construction D des lattices en utilisant les codes polaires. Cette thèse était en collaboration avec le centre de recherche de Huawei France.Future generations of wireless networks pose many challenges for the research community. In particular, these networks must be able to respond, with a certain quality of service, to the demands of a large number of connected people and objects. This drives us into quite important requirements in terms of capacity. It is within this framework that non-orthogonal multiple access methods (NOMA) have been introduced. In this thesis, we have studied and proposed a multiple access method based on the compute and forward technique and on Lattice codes while considering different lattice constructions. We have also proposed improvements to the algorithm for decoding the Sparse code multiple access (SCMA) method based on Lattice codes. In order to simplify the multi-stage decoders used in here, we have proposed simplified expressions of LLRs as well as approximations. Finally, we studied the construction D of lattices using polar codes. This thesis was in collaboration with the research center of Huawei France

Binary Subchannel Decomposition of Lattice-based Multiple Access Schemes

International audienceLattice codes used under the Compute-and-Forward paradigm suggest an alternative strategy for the standard Gaussian multiple-access channel (MAC). It has been proven that decoding an integer linear combination of the transmitted codewords enables higher data rates compared to decoding the messages individually. Recent work of Gasptar et al. proposed a new multiple access channel technique that they called Compute-and-Forward Multiple Access Channel (CFMA). The authors proved that, in the case of a two-user MAC and without time sharing, the entire capacity region is achieved using CFMA and a single-user decoder for signal to noise ratios above 1 + √ 2. Throughout this paper, we will work within the Compute-and-Forward framework. The strategy relies on lattice codes, here we will construct lattices using a multi-level coding based construction called construction D. To decode the lattice points, a multi-stage decoder (MSD) should be implemented at the receiver part. In this paper, we propose a new decoding strategy that helps to perform the standard MSD algorithm in a less complex way. The new technique is called Binary Subchannel Decomposition (BSCD). Since, we make use of MSD, we need at each level of the decoder to compute soft-inputs: Log-Likelihood ratios. However the calculations are very complex since we must compute infinite sums of exponentials at each stage. Hereinafter we give efficient LLR approximation for multi-stage decoders. Simulation results about the performance of BSCD are included and compared to the performance of the standard multi-stage decoder

LLR Computation for Multistage Decoding

International audienceDue to their linear and highly symmetrical structure , lattices are becoming of a great interest as potential transmission schemes. Lattice codes suggest a common view of channel and source coding and new tools for the analysis of information network problems. Several constructions have been proposed to build these lattices, some of which are based on multi-level coding and multistage decoding such as constructions D and πD. Soft-decision decoders corresponding to the different nested error-correcting codes used to construct such lattices need at each stage the computation of a soft input, namely Log-Likelihood Ratios. In this paper, we give an efficient computation of LLRs based on Jacobi theta functions for three different types of constructions; Binary construction D, Quaternary construction D and Binary construction πD

Haplotypes of TNFα/β Genes Associated with Sex-Specific Paranoid Schizophrenic Risk in Tunisian Population

Several medical research findings have announced a strong association between the biology of cytokines and various brain activities. Since growing evidences suggest the crucial and complex role of the tumor necrosis factor in the CNS, we have hypothesized that functional genetic variants of the LTA and TNFA genes (LTA +252A/G (rs909253) and TNFA −857C/T (rs1799724) and TNFA −238G/A (rs361525)) may be involved in the predisposition to schizophrenia. This research is based on a case-control study. The RFLP-PCR genotyping was conducted on a Tunisian population composed of 208 patients and 208 controls. We found a strong significant overrepresentation of the minor alleles (G, T, and A, respectively) in all patients compared with controls (p=0.003, OR=1.55; p=0.005, OR=1.78; and p=0.0001, OR=1.74, respectively). This correlation was confirmed for male but not for female patients. Interestingly, the frequencies of the minor alleles were significantly more common among patients with paranoid schizophrenia when compared with controls (p=0.003, OR=1.75; p=5·10−6, OR=3.04; and p=4·10−6, OR=2.35, respectively). This potential association was confirmed by a logistic binary regression analysis only for the development of the paranoid form of schizophrenia (p=0.001/OR=2.6; p=0.0002/OR=3.2; and p=0.0004/OR=3.1, respectively) and remained not significant for the other subtypes. Moreover, our study showed an important association between GCA haplotype and the development of this pathological form (p=10−4, OR=3.71). In conclusion, our results proved a significant association between the three polymorphisms and paranoid schizophrenia, at least in the Tunisian population, suggesting a substantially increased risk for paranoid schizophrenia with dominant inheritance of these three minor alleles

Sequence and structural analyses of NSP4 proteins from human group A rotavirus strains detected in Tunisia

The NSP4 protein of group A rotavirus (RVA) has been recognized as a viral enterotoxin and plays important roles in viral pathogenesis and morphogenesis. Domains involved in structural and functional interactions have been proposed mainly based on the simian SA11 strain.publisher: Elsevier articletitle: Sequence and structural analyses of NSP4 proteins from human group A rotavirus strains detected in Tunisia journaltitle: Pathologie Biologie articlelink: http://dx.doi.org/10.1016/j.patbio.2013.10.006 content_type: article copyright: Copyright © 2014 Published by Elsevier Masson SASstatus: publishe

Molecular analysis of adenovirus strains responsible for gastroenteritis in children, under five, in Tunisia

Purpose of work: Enteric Adenovirus (EAdV) is recognized as one of the most commonly identified agents responsible for severe acute gastroenteritis (AGEs) in the stools of infants.We sought to determine the rate of human adenovirus (HAdV) infections, and the genotypic characterization of circulating strains of HAdV in children under 5 years of age with AGEs in university and regional hospitals, located in the Center-East of Tunisia, from January 2014 to December 2016. Methods: A classic PCR was performed on 582 stool samples taken within 5 days of the onset of symptoms. Chosen positive samples were sequenced, and some of the results were confirmed by the Next Generation Sequencing technique (NGS). Partial nucleotide sequences of the Hexon gene obtained in this study were compared with the NCBI GenBank database using BLAST. Multiple sequence alignment and phylogenetic analysis were conducted using MEGA6 software. The phylogenetic tree was generated using the maximum-likelihood method and bootstrap analysis was performed with 1000 replications. Results: Out of 582 samples, 52 (8.93 %) cases were positive for HAdV, with a male predominance (57.4 %). Phylogenetic analyses showed that Tunisian HAdV strains clustered into five HAdV lineages corresponding to serotypes F41 (14/28), C2 (9/28), C5 (3/28), E4 (1/28), and A18 (1/28). HAdV was more frequent in children aged up to 12 months, as compared to the other age groups. The HAdV activity was noted in almost all the months of the year with a peak in autumn, in 2014 and 2015, and in winter in 2016. Conclusion: This study showed that infections with HAdV species were frequent in children suffering from AGE with the predominance of HAdV F41 and C2. This result underlines the importance of regular monitoring of circulating genotypes, and it could be useful for future epidemiological research