215 research outputs found
YAPI, un nouvel îlot de pathogénicité des Yersinia entéropathogènes
No full textLes îlots génomiques bactériens sont des éléments génétiques transmis latéralement entre microorganismes phylogénétiquement distants. Leur origine exogène est notamment illustrée par un contenu en guanine et cytosine (GC% ou coefficient de Chargaff) et un usage des codons différents de ceux du chromosome ainsi que par la présence de gènes impliqués dans la mobilisation de l'ADN. Parmi les îlots génomiques, les îlots de pathogénicité transportent plus particulièrement des gènes de virulence, dont la dissémination favorise l'émergence de nouvelles espèces pathogènes. Bien que certains îlots aient été identifiés chez des espèces éloignées, il n'a jamais été possible d'orienter et de reconstituer leur transfert. Nous avons mis à jour chez Yersinia pseudotuberculosis, une bactérie à Gram négatif responsable d'infections digestives, une nouvelle adhésine fimbriale impliquée dans sa virulence. Ces pili, dits de type IV, sont synthétisés grâce à un opéron de 11 gènes pil, qui n'est présent que chez 40% des souches de l'espèce et possède un GC% plus élevé que le reste u chromosome. Le séquençage des régions flanquant l'opéron pil a révélé que ces gènes portés par un nouvel îlot de pathogénicité de 98 Kilobases. Dénommé YAPI pour Yersinia Adhesion Pathogenicity Island, il ne porte pas d'autres gènes de virulence que ceux codant les pili de type IV. La découverte d'un îlot apparenté chez Y. enterocolitica et Salmonella enterica, deux autres espèces entéropathogènes, indiquait que ces bactéries se seraient transmises le même élément au cours de l'évolution. Grâce à l'utilisation des propriétés génomiques de ces bactéries nous avons pu identifier le plasmide à l'origine de ces îlots de pathogénicité et démonter que S. enterica l'avait transféré au genre Yersinia, avant sa spéciation.Bacterial genomic islands are genetic elements which are horizontally transferred between distantly-related taxons. The islands' foreign origin is supported by a codon usage and guanosine (G) and cytosine (C) content which often differ from the host's chromosomal core, as well by as the presece of a range of mobility genes involved in DNA transmission. Pathogenicity islands (PAIs) are genomic islands harbouring virulence genes, and their spreading throughout the bacterial world promotes the emergence of new pathogenic species. Although a few PAIs have been described in distant genera, evolutionary scenarios relating and signposting successive transfers had not previously been demonstrated. We discovered that Yersinia pseudotuberculosis (a gram-negative, enteropathogenic species) produsces type IV pili which contribute to bacterial pathogenicity. These fimbriae are encoded by a elevent-gene pil polycistronic unit: it exhibits a higher GC content than that of the Yersinia chromosome and is present in only 40% of the species' strains. After sequencing its flanking regions, we established that the pil locus was located on a novel PAI that we refer to as YAPI, for Yersinia Adhesion Pathogenicity Island. Despite its large size (98 kilobases), YAPI does not contain any otehr virulence genes. Closely-related PAIs were detected in two other enteric pathogens, Y. enterocolitica and Salmonella enterica. Using genometrics, we demonstrated that YAPI was transmitted from Salmonella to Yersinia prior to speciation of Y. pseudotuberculosis and Y. enterocolitica.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF
Designing a resource-efficient data structure for mobile data systems
No full textDesigning data structures for use in mobile devices requires attention on optimising data volumes with associated benefits for data transmission, storage space and battery use. For semi-structured data, tree summarisation techniques can be used to reduce the volume of structured elements while dictionary compression can efficiently deal with value-based predicates. This project seeks to investigate and evaluate an integration of the two approaches. The key strength of this technique is that both structural and value predicates could be resolved within one graph while further allowing for compression of the resulting data structure. As the current trend is towards the requirement for working with larger semi-structured data sets this work would allow for the utilisation of much larger data sets whilst reducing requirements on bandwidth and minimising the memory necessary both for the storage and querying of the data
Does Time Inconsistency Problem Apply For Turkish Monetary Policy?
No full textWe analyze the implications of the time inconsistency problem for the Turkish monetary policy in the last two decades. After deriving the restrictions that the Barro and Gordon model imposes on a time series model for inflation and output, we show that the time inconsistency problem can explain both the short-run and the long-run behaviour of inflation and output in the Turkish economy. The results also reveal that the Turkish monetary policymakers have put more emphasis on output stability than price stability in the last decade.Inflation, Turkish Economy, Time Inconsistency, Kalman Filter
Dynamic Analysis of the Behavioural Patterns of the Largest Commercial Banks in the Russian Federation
No full textThis paper presents a pattern behavio ral analysis of 100 largest Russian commercial banks by total assets during an eight- year period: from the first quarter of 1999 to the second quarter of 2007. Bank performance indicators are analyzed. Structural similarities in the development of the banks are examined. A cluster analysis is applied to determine banks with a similar structure of operations. This analysis allows to estimate how the structure of the Russian banking system has been changing over time. In particular, it allows to identify prevailing patterns in the behavior of Russian commercial banks and to analyze the stability of their position in a particular pattern.Bank, dynamic pattern analysis, cluster analysis
Compressed materialised views of semi-structured data
No full textQuery performance issues over semi-structured data have led to the emergence of materialised XML views as a means of restricting the data structure processed by a query. However preserving the conventional representation of such views remains a significant limiting factor especially in the context of mobile devices where processing power, memory usage and bandwidth are significant factors. To explore the concept of a compressed materialised view, we extend our earlier work on structural XML compression to produce a combination of structural summarisation and data compression techniques. These techniques provide a basis for efficiently dealing with both structural queries and valuebased predicates. We evaluate the effectiveness of such a scheme, presenting results and performance measures that show advantages of using such structures
Health-related quality of life among school children with parasitic infections : findings from a national cross-sectional survey in Côte d'Ivoire
No full textParasitic infections are still of considerable public health relevance, notably among children in low- and middle-income countries. Measures to assess the magnitude of ill-health in infected individuals, however, are debated and patient-based proxies through generic health-related quality of life (HrQoL) instruments are among the proposed strategies. Disability estimates based on HrQoL are still scarce and conflicting, and hence, there is a need to strengthen the current evidence-base.; Between November 2011 and February 2012, a national school-based cross-sectional survey was conducted in Côte d'Ivoire. Children underwent parasitological and clinical examination to assess infection status with Plasmodium and helminth species and clinical parameters, and responded to a questionnaire interview incorporating sociodemographic characteristics, self-reported morbidity, and HrQoL. Validity analysis of the HrQoL instrument was performed, assessing floor and ceiling effects, internal consistency, and correlation with morbidity scores. Multivariate regression models were applied to identify significant associations between HrQoL and children's parasitic infection and clinical status.; Parasitological examination of 4,848 children aged 5-16 years revealed Plasmodium spp., hookworm, Schistosoma haematobium, Schistosoma mansoni, Ascaris lumbricoides, and Trichuris trichiura prevalences of 75.0%, 17.2%, 5.7%, 3.7%, 1.8%, and 1.3%, respectively. Anemic children showed a significant 1-point reduction in self-rated HrQoL on a scale from 0 to 100, whereas no significant negative association between HrQoL and parasite infection was observed. The 12-item HrQoL questionnaire proofed useful, as floor and ceiling effects were negligible, internally consistent (Cronbach's alpha = 0.71), and valid, as revealed by significant negative correlations and associations with children's self-reported and clinically assessed morbidity.; Our results suggest that HrQoL tools are not sufficiently sensitive to assess subtle morbidities due to parasitic infection in Ivorian school-aged children. However, more advanced morbid sequelae (e.g., anemia), were measurable by the instrument's health construct. Further investigations on health impacts of parasitic infection among school-aged children and refinement of generic HrQoL questionnaires are warranted
ULTIMATE CAPACITIES OF FRAMES WITH STRAIN-SOFTENING CONNECTIONS
No full text3rd International Conference on Steel and Aluminium Structures (ICSAS 95) -- MAY 24-26, 1995 -- ISTANBUL, TURKEYWOS: A1995BD44D00028…Bogazici Univ, Dept Civil Engn, Sci & Tech Res Council Turkey, ARCELIK, Bogazici Univ Fdn, Bogazici Univ Printing House, Eczacibasi ASKAYNAK, ENKA, F 16 Syst Programming Off, TEKIZ, TOYOTASA, Turkish Airlines, TUBITAK, UNESCO, YAPI MERKEZ
Cost Efficiency, Scale Economies, and Technological Progress in Turkish Banking
No full textThis paper uses a three input–three output Fourier-flexible cost function specification to investigate cost efficiency, scale economies, and technological progress in the Turkish banking system over the period 1988-1998. Our findings suggest that the Turkish banking system has a significant inefficiency problem. Although the annual inefficiency average decreased over the sample period due to the financial liberalization, commercial banks in the sector operated more inefficiently than their U.S. and European counterparts. The results suggest the existence of significant economies of scale for all groups in the sample and no evidence of diseconomies of scale even for larger banks. The results also indicate the existence of technological progress between 1988 and 1991.Cost Efficiency, Technological Progress, Fourier-Flexible Cost Function, Banking
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