Academic literature on the topic 'Trafic viral'
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Journal articles on the topic "Trafic viral"
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Luethy, Lauren N., and Julie K. Pfeiffer. "Viral Infection Brings Mitochondrial Traffic to a Standstill." Cell Host & Microbe 11, no. 5 (May 2012): 420–21. http://dx.doi.org/10.1016/j.chom.2012.05.001.
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Enserink, M. "AVIAN INFLUENZA: Keeping Track of Viral Air Traffic." Science 310, no. 5747 (October 21, 2005): 428. http://dx.doi.org/10.1126/science.310.5747.428.
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Morse, Stephen S. "Emerging Viruses: Defining the Rules for Viral Traffic." Perspectives in Biology and Medicine 34, no. 3 (1991): 387–409. http://dx.doi.org/10.1353/pbm.1991.0038.
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Roman, Laura M., and Henrik Garoff. "Revelation through exploitation: the viral model for intracellular traffic." Trends in Biochemical Sciences 10, no. 11 (November 1985): 428–32. http://dx.doi.org/10.1016/0968-0004(85)90024-6.
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Rosas-Acosta, Germán, Sharon C. Braunagel, and Max D. Summers. "Effects of Deletion and Overexpression of the Autographa californica Nuclear Polyhedrosis Virus FP25KGene on Synthesis of Two Occlusion-Derived Virus Envelope Proteins and Their Transport into Virus-Induced Intranuclear Membranes." Journal of Virology 75, no. 22 (November 15, 2001): 10829–42. http://dx.doi.org/10.1128/jvi.75.22.10829-10842.2001.
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ABSTRACT Partial deletions within Autographa californica open reading frame 61 (FP25K) alter the expression and accumulation profile of several viral proteins and the transport of occlusion-derived virus (ODV)-E66 to intranuclear membranes during infection (S. C. Braunagel et al., J. Virol. 73:8559–8570, 1999). Here we show the effects of a full deletion and overexpression of FP25K on the transport and expression of two ODV envelope proteins, ODV-E66 (E66) and ODV-E25 (E25). Deletion and overexpression of FP25K substantially altered the levels of expression of E66 during infection. Compared with cells infected with wild-type (wt) virus, the levels of E66 were reduced fivefold in cells infected with a viral mutant lacking FP25K (ΔFP25K) and were slightly increased in cells infected with a viral mutant overexpressing FP25K (FP25Kpolh). In contrast, no significant changes were observed in the levels of E25 among wt-, ΔFP25K-, and FP25Kpolh-infected cells. The changes observed in the levels of E66 among the different viral mutants were not accompanied by changes in either the time of synthesis, membrane association, protein turnover, or steady-state transcript abundance. Deletion of FP25K also substantially altered the transport and localization of E66 during infection. In cells infected with the ΔFP25K mutant virus, E66 accumulated in localized regions at the nuclear periphery and the outer nuclear membrane and did not traffic to intranuclear membranes. In contrast, in cells infected with the FP25Kpolh mutant virus E66 trafficked to intranuclear membranes. For comparison, E25 was normally transported to intranuclear membranes in both ΔFP25K- and FP25Kpolh-infected cells. Altogether these studies suggest that FP25K affects the synthesis of E66 at a posttranscriptional level, probably by altering the translation of E66; additionally, the block in transport of E66 at the nuclear envelope in ΔFP25K-infected cells suggests that the pathway of E66 trafficking to the inner nuclear membrane and intranuclear microvesicles is specifically regulated and must be influenced by factors that do not control the traffic of E25.
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Lidsky, Peter V., Stanleyson Hato, Maryana V. Bardina, Alexei G. Aminev, Ann C. Palmenberg, Eugene V. Sheval, Vladimir Y. Polyakov, Frank J. M. van Kuppeveld, and Vadim I. Agol. "Nucleocytoplasmic Traffic Disorder Induced by Cardioviruses." Journal of Virology 80, no. 6 (March 15, 2006): 2705–17. http://dx.doi.org/10.1128/jvi.80.6.2705-2717.2006.
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ABSTRACT Some picornaviruses, for example, poliovirus, increase bidirectional permeability of the nuclear envelope and suppress active nucleocytoplasmic transport. These activities require the viral protease 2Apro. Here, we studied nucleocytoplasmic traffic in cells infected with encephalomyocarditis virus (EMCV; a cardiovirus), which lacks the poliovirus 2Apro-related protein. EMCV similarly enhanced bidirectional nucleocytoplasmic traffic. By using the fluorescent “Timer” protein, which contains a nuclear localization signal, we showed that the cytoplasmic accumulation of nuclear proteins in infected cells was largely due to the nuclear efflux of “old” proteins rather than impaired active nuclear import of newly synthesized molecules. The nuclear envelope of digitonin-treated EMCV-infected cells permitted rapid efflux of a nuclear marker protein. Inhibitors of poliovirus 2Apro did not prevent the EMCV-induced efflux. Extracts from EMCV-infected cells and products of in vitro translation of viral RNAs contained an activity increasing permeability of the nuclear envelope of uninfected cells. This activity depended on the expression of the viral leader protein. Mutations disrupting the zinc finger motif of this protein abolished its efflux-inducing ability. Inactivation of the L protein phosphorylation site (Thr47→Ala) resulted in a delayed efflux, while a phosphorylation-mimicking (Thr47→Asp) replacement did not significantly impair the efflux-inducing ability. Such activity of extracts from EMCV-infected cells was suppressed by the protein kinase inhibitor staurosporine. As evidenced by electron microscopy, cardiovirus infection resulted in alteration of the nuclear pores, but it did not trigger degradation of the nucleoporins known to be degraded in the poliovirus-infected cells. Thus, two groups of picornaviruses, enteroviruses and cardioviruses, similarly alter the nucleocytoplasmic traffic but achieve this by strikingly different mechanisms.
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Suikkanen, Sanna, Tuula Aaltonen, Marjukka Nevalainen, Outi Välilehto, Laura Lindholm, Matti Vuento, and Maija Vihinen-Ranta. "Exploitation of Microtubule Cytoskeleton and Dynein during Parvoviral Traffic toward the Nucleus." Journal of Virology 77, no. 19 (October 1, 2003): 10270–79. http://dx.doi.org/10.1128/jvi.77.19.10270-10279.2003.
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ABSTRACT Canine parvovirus (CPV), a model virus for the study of parvoviral entry, enters host cells by receptor-mediated endocytosis, escapes from endosomal vesicles to the cytosol, and then replicates in the nucleus. We examined the role of the microtubule (MT)-mediated cytoplasmic trafficking of viral particles toward the nucleus. Immunofluorescence and immunoelectron microscopy showed that capsids were transported through the cytoplasm into the nucleus after cytoplasmic microinjection but that in the presence of MT-depolymerizing agents, viral capsids were unable to reach the nucleus. The nuclear accumulation of capsids was also reduced by microinjection of an anti-dynein antibody. Moreover, electron microscopy and light microscopy experiments demonstrated that viral capsids associate with tubulin and dynein in vitro. Coprecipitation studies indicated that viral capsids interact with dynein. When the cytoplasmic transport process was studied in living cells by microinjecting fluorescently labeled capsids into the cytoplasm of cells containing fluorescent tubulin, capsids were found in close contact with MTs. These results suggest that intact MTs and the motor protein dynein are required for the cytoplasmic transport of CPV capsids and contribute to the accumulation of the capsid in the nucleus.
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Haupt, Sophie, Graham H. Cowan, Angelika Ziegler, Alison G. Roberts, Karl J. Oparka, and Lesley Torrance. "Two Plant–Viral Movement Proteins Traffic in the Endocytic Recycling Pathway." Plant Cell 17, no. 1 (December 17, 2004): 164–81. http://dx.doi.org/10.1105/tpc.104.027821.
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Meng, Ji Xian, and Xin Zhong Lu. "The Application of Graph Theory Method in the Problem of Traffic Patrol Police Service Platform’s Site Selection." Applied Mechanics and Materials 246-247 (December 2012): 723–27. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.723.
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In order to maintain good social order, we need set some traffic patrol police service platforms at the vital communication line and important position of the city. In this paper, we will use graph theory method to deal with the problem of traffic patrol police service platform’s site selection for a fixed unban area. When there are some emergency events happened in the fixed area, these traffic patrol police service platforms should make corresponding response and close vital communication line immediately. So we also need to establish a optimal mathematics model to obtain a reasonable arrangement for closing the vital communication line. Meanwhile, building a scientific index system will help us to measure whether these arrangements reasonable or not.
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Sawalka, Deepak R. "Traffic Sign Classification." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (September 30, 2021): 107–15. http://dx.doi.org/10.22214/ijraset.2021.37921.
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Abstract: The traffic signs engraved on the streets nowadays improve traffic security by advising the driver regarding speed limits or any further potential perils like profound thrilling streets, inescapable fix street works or any common intersections. With the quick improvement of economy and innovation in the cutting edge society, vehicles have become an imperative method for transportation in the day by day travel of individuals. Albeit the fame of autos has acquainted impressive comfort with individuals, it has additionally caused a various traffic security issues that can't be overlooked, for example, gridlock and successive street mishaps. Traffic security issues are to a great extent brought about by abstract reasons identified with the driver, like obliviousness, inappropriate driving activity and resistance with traffic rules, and keen vehicles have become a compelling way to wipe out these human components. Self-driving innovation can help, or even autonomously complete the driving activity, which is vital to free the human body and extensively lessen the rate of mishaps. Traffic sign identification and acknowledgment are significant in the advancement of astute vehicles, which straightforwardly influences the execution of driving practices. Traffic sign identification and grouping is of vital significance for the fate of independent vehicle innovation. We benchmark the commented on dataset with AI baselines Convolutional Neural Organizations (CNN). Computational strategies for AI (ML) have shown their importance for the projection of possible outcomes for educated choices. AI calculations have been applied for quite a while in numerous applications. An information driven methodology with higher precision as here can be extremely valuable for a proactive reaction from the public authority and residents. At long last, we propose a bunch of exploration openings and arrangement justification for additional useful applications. Keywords: Convolutional Neural Networks, Traffic sign detection, Traffic safety, Computational Methods, machine Learning Algorithms
Dissertations / Theses on the topic "Trafic viral"
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Renault, Noémie. "Trafic intracellulaire de la protéine Gag du virus Foamy." Paris 7, 2009. http://www.theses.fr/2009PA077154.
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Les virus foamy sont des rétrovirus complexes qui appartiennent à la famille des spumaviridae. Ces rétrovirus présentent de nombreuses particularités qui les différencient des orthorétrovirus comme l'existence d'ADN viral infectieux dans la particule virale ou celle d'un ARNm codant pour la polyprotéine Pol, ou encore l'absence d'un facteur de régulation post-transcriptionnelle de type Rev ou Rex. De la même manière, les protéines Gag ne présentent pas les caractéristiques fondamentales retrouvées chez les autres rétrovirus comme le clivage en matrice, capside et nucléocapside. Nous avons focalisé notre travail sur ces protéines structurales et sur leurs rôles tant lors des étapes précoces que tardives. Lors des étapes précoces, la polyprotéine Gag protège le génome viral et le guide sur le réseau microtubulaire jusqu'à la membrane nucléaire. Dans les cellules qui cyclent, les particules,virales enfantes du virus foamy sont retrouvées intactes au centrosome à partir de 4 h post-infection. La capside subit alors un désassemblage en partie dépendant de la protéase virale. A l'inverse, dans les cellules quiescentes, nous montrons que les capsides restent structurées autour centrosome. A la reprise du cycle cellulaire, le cycle réplicatif viral reprend avec le déshabillage de la capside et l'intégration du provirus. Les protéases cellulaires et virales, qui interviennent lors de la décapsidation, semblent ainsi inactives lorsque les cellules sont en phase GO. De manière non exclusive, les sites de clivage de ces protéases sur les protéines structurales du virus pourraient être inaccessibles dans ces conditions. Les protéines Gag jouent également un rôle clé lors des étapes tardives de l'infection, en étant responsables de l'assemblage des capsides qui a lieu dans le cytoplasme, autour du centrosome. De manière intéressante, avant l'assemblage, ces protéines transitent dans le noyau. Nous nous sommes intéressés à cette étape nucléaire et montrons que la protéine Gag est exportée du noyau grâce à un signal d'export nucléaire riche en leucine et sensible à la leptomycine B, présent dans la partie N-terminale de la protéine. Une protéine Gag mutée dans ce domaine est non seulement incapable de quitter le noyau mais interfère négativement avec la réplication d'un virus sauvage. Nous suggérons que les protéines Gag des virus foamy pourraient intervenir dans l’export nucléaire de l’ARN viral lors des étapes tardives de l'infectionFoamy viruses (FVs) are complex exogenous animal retroviruses that differ in many aspects of their life cycle from the orthoretroviruses such as human immunodefîciency virus (HIV). In particular, in FVvs, Gag and Pol proteins are expressed independently of one another, and both proteins undergo single clivage events. None of the conventional Gag landmarks of exogenous retroviruses, such as the major homology region or Cys-His motifs, are found in this protein. Instead, FV Gag harbors conserved C-terminal basic motifs, referred to as Gly-Arg (GR) boxes. Although the first GR (GRI) box binds viral nucleic acids and is required for viral genome packaging, the second (GRII) harbors a nuclear localization sequence (NLS) at its C-terminus, targeting Gag to the nucleus early after infection. GRII also contains a chromatin binding sequence (CBS) in its N-terminus, tethering the FV incoming pre-integration complex onto host chromosomes. The present work focuses on the structural Gag proteins, in early and late stages of infection. Troviral Gag proteins are involved in early stages of infection such as trafficking of incoming viruses nd nuclear import. FV Gag protein uses the microtubule network to reach the nucleus. In cycling cells,FV articles are structured at the centrosome 4 h post-infection. Then, the viral protease helps capsid for ncoating. In quiescent cells, we have shown that viral particles remain structured at the centrosome during everal weeks and that uncoating does not occur : this step is a limiting factor for infection although viral articles are still infectious. Upon cells reactivation, viral capsids undergo proteolysis and disassembly, llowing infection to proceed. During the late stages of infection, Gag undergoes transient nuclear trafficking after it synthesis, before returning back to the cytoplasm for capsid assembly and virus egress. The functional role of this nuclear stage, as well as the molecular mechanisms responsible for Gag nuclear export, are not understood. Here, we identify a leptomycin-sensitive nuclear export sequence (NES) within the N-terminus of the primate foamy virus Gag protein that is absolutely required for the completion of late stages of virus replication. Point mutation of conserved residues within this motif leads to nuclear retention of Gag and dramatically affects viral replication. Moreover, complementation experiments demonstrate that nuclear export-defective Gag mutants negatively interfere with virus release by sequestering wild-type Gag in the nucleus
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Bouard, David. "La glycoprotéine d'enveloppe rétrovirale : trafic intracellulaire et recrutement lors de l'assemblage viral." Lyon, École normale supérieure (sciences), 2008. http://www.theses.fr/2008ENSL0471.
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Rizkallah, Gergès. "Le role de l'interaction des cellules dendritiques avec le virus HTLV-1 dans la dissémination virale : capture ou infection productive ?" Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1099/document.
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Le virus T lymphotrope humain de type 1 (HTLV-1) est l'agent étiologique de la leucémie à cellules T de l'adulte (ATL) et de la paraparésie spastique tropicale/myélopathie associée à HTLV-1 (HAM/TSP). Chez les patients chroniquement infectés, le provirus d'HTLV-1 est majoritairement retrouvé dans les lymphocytes T CD4+. Ex vivo, on peut aussi retrouver le provirus dans les lymphocytes T CD8+, les lymphocytes B, les monocytes, les cellules dendritiques (DCs) myéloïdes, les DCs plasmacytoϊdes (pDCs) et les macrophages. In vitro, HTLV-1 est capable d'infecter productivement les cellules lymphoïdes et les cellules dendritiques dérivées de monocytes humains (MDDCs). De par leur fonction et leur distribution dans l'organisme, les DCs pourraient être les premières cellules à interagir avec HTLV-1 au cours de la primo-infection. Elles seraient ensuite capables de transmettre HTLV-1 aux lymphocytes T CD4+. Cette hypothèse est soutenue par les travaux de notre équipe qui ont montré que les MDDCs sont plus susceptibles que des lymphocytes T autologues à l'infection par HTLV-1. Ainsi, les DCs constitueraient des relais importants pour l'établissement de l'infection chronique. Dans ce contexte, nous nous sommes demandés si toutes les populations de DCs étaient également susceptibles à l'infection par HTLV-1 et si elles transmettaient similairement HTLV-1 aux lymphocytes T. Pour cela, nous avons différencié trois sous types de MDDCs après l'exposition de monocytes humains à divers cocktails de cytokines : - les IL4-DCs (pour interleukine 4 - DCs) miment les DCs immatures myéloϊdes du sang, - les TGF-β DCs (pour tumor-growth factor β - DCs) miment les DCs mucosales à phénotype tolérogène, - les IFN-α DCs (pour interféron α DC) miment les DCs activées et inflammatoires recrutées au niveau des sites d'inflammation. Nous avons aussi traité au lipopolysaccharide (LPS) des IL-4 DCs afin de générer des DCs qui sur-expriment les marqueurs de maturation CD80 et CD86. Nos résultats montrent que les IFN-α DC et les IL-4 DCs traités au LPS ne supportent pas une infection productive au contraire des TGF-β DCs et des IL4-DCs qui sont productivement infectés par HTLV-1. La restriction virale des IFN-α DC et les IL-4 DCs traitées au LPS n'est pas due à leur production d'IFN. Nous avons montré que la susceptibilité des IL4-DCs à l'infection productive par HTLV-1 est liée à leur phénotype immature. De plus, nos résultats montrent qu'HTLV-1 est internalisé par macropinocytose dans les IL-4 DCs alors qu'il est internalisé par endocytose médiée par la clathrine dans les IFN-α DCs. Enfin, nous avons pu restaurer partiellement la susceptibilité à l'infection productive des IL-4 DCs traités au LPS et celle des IFN-α DCs et nous avons pu restreindre celle des IL-4 DCs immatures en modulant le pH de leurs endosomes. Ces résultats suggèrent que le virus utilise le trafic vésiculaire pour infecter les DCs et que le pH des vésicules conditionne, au moins partiellement, le devenir de l'infection productive. De plus, parmi les IL-4 DCs, les IL-4 DCs traités au LPS et les IFN α DCs, seules les IL-4 DCs qui sont productivement infectées peuvent transmettre HTLV-1 aux lymphocytes T. En conclusion, nos résultats suggèrent que c'est le sous type de DC que rencontre HTLV- 1 lors de la primo-infection ainsi que le trafic viral d'HTLV-1 dans la DC qui conditionnent ou pas l'établissement de l'infection productive de la DC ainsi que la transmission aux lymphocytes THTLV-1 (Human T cell leukemia/lymphoma virus type 1) is the etiological agent of Adult T cell Leukemia/Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). In chronically infected patients, the provirus is mainly detected in the CD4 T-cell population and, to a lesser extent in myeloid dendritic cells (DCs), plasmacytoid DCs (pDCs), macrophages and monocytes. Among the different DCs subsets found in vivo, myeloid DCs from the blood, tolerogenic or inflammatory DCs from mucosa may first encounter HTLV-1 during blood transmission, breast-feeding or sexual transmission, respectively. They would then be able to transmit HTLV-1 to CD4 + T cells. This hypothesis is supported by the recent work of our team that showed that monocyte derived dendritic cells (MDDCs) are more susceptible to HTLV-1 infection in comparison to autologous T cells. We therefore asked whether all these DCs subsets were equally susceptible to HTLV-1 and whether the nature of the DC subset would impact HTLV-1 spread to T-cells. Human monocytes obtained from healthy blood donors were differentiated into IL-4 DCs, TGF-ß DCs or IFN-a DCs. In vitro-derived immature IL-4 DCs, TGF-ß DCs and IFN-a DCs mimic myeloid, tolerogenic and inflammatory DCs, respectively. We also generated LPS-matured IL-4 DCs that exhibited a strong maturation profile with over-expression of maturation markers. We observed HTLV-1 protein expression and provirus accumulation in IL-4 DCs and TGF-ß DCs but not in IFN-a DCs and LPS-matured IL-4 DCs. Despite their increased ability to capture HTLV-1 virion compared to IL-4 DCs and TGF-ß DCs, IFN-a DCs and LPS-matured IL-4 DCs restricted HTLV-1 productive infection. This was not due to the antiviral activity of type–I interferon produced by IFN-a DC or LPS-matured IL-4 DCs. In contrast, we showed that these differences in susceptibility to HTLV-1 infection might be linked to the maturation phenotype of the DCs subsets and to a different trafficking of HTLV-1 in IL-4 DC vs. IFN-a DC. Finally, using IL-4DCs, LPS-matured IL-4 DCs and IFN-a DCs, we demonstrate that productive infection rather than trans-infection is required for HTLV-1 transmission from DCs to CD4 T-cells. Thus, our results demonstrate that the nature of the DCs encountered by HTLV-1 during primo-infection and the trafficking route of the virus through the vesicular pathway of these cells determine the efficiency of viral transmission to T-cells
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Charrat, Coralie. "Formulation de nanoparticules d’ADN fonctionnalisées par des peptides ligands des chaînes LC8 de la dynéine pour améliorer le trafic intracellulaire dans le transfert de gènes non viral." Thesis, Nice, 2016. http://www.theses.fr/2016NICE4017/document.
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L’objectif repose sur l’élaboration de vecteurs d’ADN fonctionnalisés par des séquences peptidiques, DLC8-AS, ciblant les chaînes légères LC8 de la dynéine cytoplasmique, pour obtenir un transport actif jusqu’au noyau le long des microtubules (MTs). Des travaux précédents, menés sur des fluosphères fonctionnalisées par des DLC8-AS, ont montré une efficacité remarquable à condition de travailler avec de hauts taux de ligands. De tels niveaux de ligands ne sont pas transposables à des nanoparticules (NPs) d’ADN car ils affectent grandement leur stabilité colloïdale. Pour compenser cela, nous avons développé dans cette thèse, des NPs d’ADN faiblement fonctionnalisées (2-10 mol %) portant des dimères de DLC8-AS afin de bénéficier d'un effet dimérique vis-à-vis de la dynéine qui augmente l'affinité. Parmi les systèmes testés, 2 ont montré un gain lié à l’effet dimérique des DLC8-AS. Le 1er est basé sur un amphiphile cationique dimérisable de la cystéine, utilisé avec son homologue pegylé portant un motif DLC8-AS, pour produire, via l’oligomérisation des thiols, une population monodisperse de petites NPs d’ADN décorées (~60 nm). Les expériences menées sur cellules HeLa ont montré que les NPs décorées par les dimères de DLC8-AS avaient des efficacités de transfection améliorées (~250 fois) grâce à un mécanisme dépendant du système dynéine/MTs. Dans l’autre système, la surface de polyplexes de PEI a été décorée avec des amphiphiles octaarginine mono- ou bis-DLC8-AS. De façon remarquable, l’efficacité de transfection des polyplexes portant les ligands dimériques a été améliorée d’un facteur 50 par rapport au JetPEI standard. Ici encore, le mécanisme dépend des MTsThe aim consists in engineering DNA carriers functionalized by peptide sequences, DLC8-AS, targeting the LC8 light chains of cytoplasmic dynein, to promote active transport towards the nucleus along the microtubules (MTs).Dépôt de thèseDonnées complémentairesPrevious works based on polystyrene fluospheres functionalized with DLC8-AS, showed a noteworthy transfection enhancement but as a cost of high levels of ligands. Such levels of functionalization are unsuitable for maintaining sufficient colloidal stability of DNA nanoparticles (NPs). In order to compensate for this, we developed in this thesis weakly functionalized DNA NPs (2-10 mol %) bearing dimers of DLC8-AS to benefit from a dimeric effect toward the dynein which increase the affinity. Among our designed systems, two revealed the benefit from taking advantage from the dimeric effect of DLC8-AS. The 1st one relies on a cationic and dimerizable cysteine based amphiphile, which was used with its dimerizable pegylated homologue containing DLC8-AS, to produce, through a thiol-disulfide oligomerisation process, a monodisperse population of small sized functionalized DNA NPs (~60 nm). Experiments carried out onto HeLa cells, showed that DNA NPs functionalized with DLC8-AS dimers exhibited enhanced transfection properties (~250 times) through a dynein/MTs dependant mechanism. The second consists in functionalizing the surface of PEI polyplexes with octaarginine amphiphiles carrying a mono- or bis-DLC8-AS. Remarkably, the transfection efficiency of polyplexes bearing the dimeric ligands was increased by a 50 times factor compared to the JetPEI golden standard. Here too, the mechanism strongly depends on MTs
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Pires, Ricardo. "Etudes structurales et fonctionnelles de la protéine ALIX." Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00332814.
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Alix est une protéine adaptatrice impliquée dans plusieurs processus intracellulaires, dont l'apoptose, l'endocytose et le trafic membranaire, le bourgeonnement de certains rétrovirus (ex. HIV-1, EIAV) à travers la membrane plasmique ou encore la cytokinèse. Alix est constituée de trois domaines majeurs: un domaine BRO N-terminal, un domaine spécifique « en V » central (Alix-V) et un domaine C-terminal riche en prolines (PRD). Nous avons montré que la forme tronquée en C-terminal au niveau du domaine PRD (Alix-∃PRD) formait des monomères et des dimères en solution, et que le domaine Alix-V était suffisant pour permettre cette dimérisation. La diffraction de rayons X aux petits angles (SAXS) a montré que Alix-∃PRD se structurait en une forme incurvée et allongée qui rappelle les domaines BAR impliqués dans les phénomènes d'incurvation de membrane. Bien que l'interaction d'Alix avec la membrane ait été mise en évidence in vitro, sa capacité à déformer la membrane doit encore être confirmée. En outre, nous avons déterminé lors d'expériences de microcalorimétrie que les formes monomériques et dimériques de Alix-V interagissent avec un peptide dérivé de la protéine p9 EIAV Gag avec une affinité de l'ordre du micromolaire. Des cristaux de la forme dimérique de Alix-V ont été obtenus. Ces cristaux présentaient un faible pouvoir de diffraction (10Å). En revanche, des cristaux diffractant à 3Å ont été obtenus à partir d'une forme mutante de Alix-V (Mut1) incapable de dimériser et qui se structure en une forme monomérique ouverte et allongée ; la résolution de cette structure est en cours. De plus, nous avons montré que l'absence de relarguage des particules virales (VLP) après surexpression de la forme humaine de Alix-∃Bro (résidus 358-868) pouvait être rétablie à partir de la version Mut1 de cette forme, ce qui suggère donc un rôle de cette dimérisation dans le relarguage des VLP. La protéine Alix-V dimérique a également été utilisée pour produire un antisérum Alix, qui a montré que la protéine endogène Alix pouvait être co-localiser avec les endosomes de recyclage. Enfin, nous avons montré que CHMP4B formant des structures polymériques en anneaux, pouvait interagir avec Alix. L'ensemble de ces résultats donne de nouvelles informations sur la flexibilité conformationnelle d'Alix et, associée avec CHMP4, sur son implication dans les processus de bourgeonnement membranaire. Ce travail définit également le cadre des futures analyses fonctionnelles visant à définir le rôle de la protéine dimérique Alix dans les cellules infectées par le virus HIV-1.
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Lambelé, Marie. "Etude du trafic intracellulaire des glycoprotéines d'enveloppe d'isolats primaires du virus de l'immunodéficience humaine de type 1 et de son impact sur l'assemblage viral." Tours, 2007. http://www.theses.fr/2007TOUR3801.
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Les glycoprotéines d'enveloppe (Env) de VIH-1 se caractérisent par une variabilité génétique qui peut toucher les motifs impliqués dans la régulation de leur trafic intracellulaire. Nous avons ainsi mis en évidence, pour certaines Env d'isolats primaires, un polymorphisme dans ces motifs. Nous avons pu montrer que ce polymorphisme naturel affectait la distribution intracellulaire des Env. Cette modification du trafic intracellulaire perturbe l'assemblage viral en diminuant l'incorporation des Env à la surface des virions, et de ce fait les capacités réplicatives des virus produits. Cependant, il semble que, dans les Env. De VIH-1 primaires, des déterminants additionnels, puissent modifier le trafic intracellulaire de ces protéines. Cette modification de trafic pourrait, par ailleurs, contribuer à l'échappement du virus au système immunitaire. Ces travaux amènent de nouveaux éléments sur la compréhension des moyens adoptés in vivo par le VIH-1 pour s'assurer d'une propagation optimaleThe envelope glycoprotein (Env. ) of HIV-1 is characterized by an important polymorphism that can affect motifs involved in the regulation of the intracellular trafficking. Her, we investigated four envelope genes with natural polymorphism within these motifs. We showed that this polymorphism might influence the intracellular distribution of Env. This modification affects viral assembly by diminution of Env incorporation into virions and, thus, viral replication capacity. Furthermore, it seems that additional determinants regulate intacellular trafficking of primary Env. This traffic's modification could in part contribute to viral evade from immune system. These work bring new insight in the understanding of viral life and its capacity to insure optimal propagation in vivo
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El, Meshri Salah Edin. "Etude du trafic intracellulaire de la protéine Gag du VIH et rôle de son domaine NCp7." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ025/document.
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La polyprotéine de structure Gag du VIH-1 est responsable de l’assemblage des particules virales dans les cellules infectées. Au niveau moléculaire, cette protéine s’oligomérise en formant des complexes Gag-Gag autour de deux plates-formes moléculaires, d'une part l'ARN génomique via son domaine NCp7 (NucleoCapsid protein 7) et d'autre part, la membrane plasmique via son domaine MA (Matrice). De plus, lors du trafic de Gag dans la cellule, Gag détourne les protéines ESCRT comme TSG101 et ALIX de la machinerie cellulaire afin de bourgeonner et d’être libérées dans le milieu extracellulaire. Dans cette thèse, nous avons étudié le rôle du domaine NCp7 seul ou au sein de Gag (GagNC) dans les interactions Gag-Gag et Gag-TSG101 en utilisant des approches biochimiques et de la microscopie de fluorescence quantitative. Les résultats ont montré que l'absence du domaine NCp7 affecte l’oligomerisation de Gag qui s’accumule alors dans le cytoplasme sous forme d’agrégats de taille importante. Par ailleurs, le trafic intracellulaire de Gag est affecté par les mutations dans le domaine GagNC avec une augmentation importante de temps nécessaire à Gag pour arriver à la membrane plasmique. Enfin, nous avons montré que GagNC i) renforce l’interaction entre le domaine p6 de Gag et TSG101 et ii) par sa fonction dans le trafic de Gag, est responsable de la localisation de TSG101 à la PM. Sur la base de ces résultats, des études sont maintenant en cours pour développer des tests afin d’identifier des molécules possédant un potentiel anti viraleThe Gag structural polyprotein of HIV-1 orchestrates viral particle assembly in producer cells, in a process that requires two platforms, the genomic RNA on the one hand and a membrane with a lipid bilayer, on the other. During its transportation from translating ribosomes to plasma membrane, Gag hijacks cellular proteins of the cytoskeleton and the ESCRT proteins like TSG101, Alix, etc., to egress viral particles. However, a number of questions remain to be answered before they are clearly apprehended. In this thesis, , we studied the role of the NC domain alone or as part of Gag (GagNC) in Gag-Gag and Gag-TSG101 interactions, which are essential for the assembly and budding of HIV-1 particles using quantitative fluorescent microscopy and biochemical approach. Results, showed that the absence of NC domain lead to (1) an accumulation of Gag as large aggregates that are dispersed in the cytoplasm, (2) a decrease of Gag-Gag condensation and (3) a delay for Gag-Gag complexes in reaching the PM, (4) improved interaction between Gag and TSG101, and (5) by its virtue in Gag trafficking docks TSG101 to the PM. This regulatory effect of NCp7 domain in either TSG101 or Gag or both protein- regulated pathways during virus budding can be exploited to develop inhibitors targeting HIV-1
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Paris, Joris. "Trafic intranucléaire du rétrovirus Foamy." Paris 7, 2014. http://www.theses.fr/2014PA077053.
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La protéine Gag des rétrovirus exerce plusieurs fonctions au cours du cycle réplicatif, notamment en détournant de nombreuses machineries cellulaires. Dans le cas de PFV (Prototype Foamy Virus), la protéine Gag possède un NES (Nuclear Export Signal) permettant d'exporter son ARN génomique favorisant ainsi l'assemblage des capsides virales. Nous avons identifié une séquence de loCalisation nucléolaire (NoLS) dans la partie C-terminale de la protéine Gag. Ce NoLS est composé de 2 régions, riches en arginine et en glycine qui sont nécessaires et suffisantes pour le ciblage au nucléole. L'arginine R540 est méthylée par PRMT-1 régulant ainsi les fonctions NoLS vs CBS de la protéine Gag. Pour étudier, l'étape nucléolaire du virus PFV, nous avons utilisé différentes conditions permettant de ralentir le trafic intracellulaire (hypoxie et/ou traitement à la leptomycine B) et un système de piège permettant de retenir Gag au nucléole. Dans les 2 expériences, Gag a été détectée dans le nucléole. Nous avons aussi développé une approche basée sur l'utilisation d'un ribozyme nucléolaire qui est capable de cliver spécifiquement l'ARNg de PFV au nucléoleThe structural Gag protein hijacks many cellular machineries to fulfill its distinct and fundamental roles in the replication of retroviruses. In the case of the prototype foamy virus (PFV), Gag contains a nuclear export signal (NES) which allows the gRNA-Gag complex to be exported to the cytoplasm prior to capsids assembly and virus egress. We identified a nucleolar localization sequence (NoLS) in the C-terminus of PFV Gag. This NoLS contains two regions, rich in arginine and glycine, which are necessary and sufficient for nucleolar targeting. The methylation of Arginine R540 by PRMT-1 regulates the functions NoLS vs CBS of Gag. To study the nucleolar step of PFV replication, we used different conditions that slow down intracellular trafficking (hypoxia and/or treatment with leptomycin B) and also a molecular trap system to retain Gag into the nucleolus. In both cases, Gag was detected in the nucleolus. We also developed an approach, based on a ribozyme fused to a snoRNA able to cleave specifically PFV gRNA in the nucleolus
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Grigorov, Boyan. "Studying the traffic and assembly of HIV-1 Gag." Lyon, École normale supérieure (sciences), 2007. http://www.theses.fr/2007ENSL0398.
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Vertiz, Zavaleta Julio Cesar, and Avalos Victor Eduardo Ramon. "Propuesta de mejora de niveles de servicio en la intersección vial entre la carretera Panamericana Sur km 37.5 y el puente Arica en la ciudad de Lima." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/648867.
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La Carretera Panamericana Sur km. 37.5 y el Puente Arica, es una intersección vial tipo Diamante Convencional partido sin semáforos, ubicado en el distrito de Lurín y provincia de Lima. Esta intersección presenta congestionamiento vehicular ocasionando pérdida de horas hombre. Debido a esto, se determinó los niveles de servicio actuales, a través del software Synchro 8.0, mediante aforos vehiculares tomados en campo.
Los niveles de servicio obtenidos fueron muy bajos y demoras elevadas. Como consecuencia se plantearon y modelaron con el software Synchro 8.0 diferentes propuestas para solucionar la congestión vehicular, tales como; Implementación de cruceros semafóricos con diferentes diseños, implementación de mini óvalos dentro de la intersección y en los extremos de la intersección, y un intercambio vial de tipo Diamante Divergente.
La propuesta de solución se inicia con la comparación de resultados obtenidos de las alternativas para el escenario actual y proyectado a 5 y 10 años. En consecuencia, se obtuvieron dos propuestas que solucionan la congestión vehicular actual y proyectada a 5 años. La primera es la implementación de cruceros semafórico con un carril exclusivo para el giro libre a la derecha y la segunda es la implementación de un novedoso intercambio vial de tipo Diamante Divergente, mientras que las demás propuestas no son sostenibles en la proyección del tránsito futuro. Por otro lado, si bien es cierto que ambas propuestas mejoran y dan solución al problema planteado la segunda presenta mejores niveles de servicio y menores demoras en la proyección a 10 años.The South Pan American Highway km. 37.5 and the Arica Bridge, is a Conventional Diamond-type road intersection without traffic lights, located in the district of Lurín and province of Lima. This intersection presents vehicular congestion causing loss of man-hours. Due to this, the current service levels were determined, through Synchro 8.0 software, through vehicle capacities taken in the field. The service levels obtained were very low and delays were high. As a consequence, different proposals were proposed and modeled with Synchro 8.0 software to solve vehicular congestion, such as; Implementation of traffic lights with different designs, implementation of mini ovals within the intersection and at the ends of the intersection, and a Divergent Diamond road interchange. The solution proposal begins with the comparison of results obtained from the alternatives for the current scenario and projected at 5 and 10 years. Consequently, two proposals were obtained that solve the current and projected vehicular congestion at 5 years. The first is the implementation of traffic light cruises with an exclusive lane for the free right turn and the second is the implementation of a new Divergent Diamond interchange, while the other proposals are not sustainable in the projection of future traffic. On the other hand, although it is true that both proposals improve and solve the problem posed, the second presents better levels of service and less delays in the 10-year projection.
Tesis
Books on the topic "Trafic viral"
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Spain. Legislación sobre trafico, circulacion y seguridad vial. Madrid, España: Editorial Civitas, 1993.
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Spain. Tráfico, circulación y seguridad vial. Madrid: Ministerio del Interior, Dirección General de Tráfico, 1990.
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Castilla, Gustavo Ordoqui. Ley de tránsito y seguridad vial, 18,191. Montevideo, Uruguay: La Ley Uruguay, 2009.
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Isasi Ortiz de Barrón, Fernando, ed. Tráfico y seguridad vial. Cizur Menor (Navarra): Editorial Aranzadi, 2003.
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1960-, Linamen Karen Scalf, ed. Vital connections. Colorado Springs, CO]: LearningRx, 2012.
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Miguel, Amando de. Sociología de la seguridad vial. Madrid: Centro de Investigaciones Sociológicas, 2003.
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León, Luis Carlos Rodríguez. Seguridad vial: Crónica de una reforma penal. Sevilla: Instituto Andaluz de Administración Pública, 2008.
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León, Luis Carlos Rodríguez. Seguridad vial: Crónica de una reforma penal. Sevilla: Instituto Andaluz de Administración Pública, 2008.
Find full textBook chapters on the topic "Trafic viral"
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Bellanca, Nicolò, and Luca Pardi. "Qualche riflessione finale." In Studi e saggi, 197–200. Florence: Firenze University Press, 2020. http://dx.doi.org/10.36253/978-88-5518-195-2.17.
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We introduce the concept of "tragic choices": those that concern our vital and identity experiences. As in the tragedies of classical Greek theater, there are circumstances in which there is no right and wrong, since theses capable of exhibiting arguments of almost equal strength are opposed. This is what happens today due to the contrast between economic and ecological predicaments: there is no optimal choice in this regard, valid always and in any case, that allows us to neglect and forget the other option. This is why, in pragmatic terms, the concept of “a-growth” is useful: we check on a case-by-case basis when economic growth can still be useful, when it should be slowed down and when it needs to be reduced. This approach is part of the research, itself pragmatic, of the "boundaries of the biosphere". These are not rigid limits, but constraints that must be interpreted and adapted, based on the idea of "being happy", where being satisfied means making the biosphere feel good with us inside.
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Arias, C. F., D. Silva-Ayala, P. Isa, M. A. Díaz-Salinas, and S. López. "Rotavirus Attachment, Internalization, and Vesicular Traffic." In Viral Gastroenteritis, 103–19. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-802241-2.00006-7.
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Sträter, Jörn, and Peter Möller. "TRAIL and Viral Infection." In TRAIL (TNF-Related Apoptosis-Inducing Ligand), 257–74. Elsevier, 2004. http://dx.doi.org/10.1016/s0083-6729(04)67014-2.
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Weitz, Joshua S. "Evolutionary Dynamics of Viruses or Microbes, but Not Both." In Quantitative Viral Ecology. Princeton University Press, 2016. http://dx.doi.org/10.23943/princeton/9780691161549.003.0004.
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This chapter discusses the evolutionary dynamics of viruses. Preexisting variation in host phenotypes include variants with different levels of susceptibility to viruses, including complete resistance. Formative studies of the basis of the mutation rate relied upon virus–host interactions and the possibility of the evolution of resistance to infection. Viruses represent a strong selective pressure and can induce evolution among hosts. Host evolution, as induced by viruses, includes novel forms of ecological dynamics, including cryptic dynamics. Infection of hosts represents a strong selective pressure for viruses. Viruses that differ in their life history traits vary in their fitness and can invade and replace existing viral strains. The latent period represents a model trait for the further study of the evolution of intermediate phenotypes. Evolution among other traits is also possible, including who infects whom.
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Armstrong, John. "The Role of Coastal Shipping in UK Transport: An Estimate of Comparative Traffic Movements in 1910." In The Vital Spark, 243–60. Liverpool University Press, 2009. http://dx.doi.org/10.5949/liverpool/9780986497308.003.0013.
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This chapter aims to estimate the amount of work performed by the coastal shipping industry in 1910 in relation to the rail and canal transport counterparts. It examines the services offered by the coastal industry in this period that the railway could not provide - such as ferrying to remote regions such as the Isle of Man, Isle of Wight, and Scottish islands. It compares and contrasts rail, canal, and coastal services by examining freight traffic; coal shipping; bills of entry; the Royal Commission on Canals; steamship company records; and Parliamentary papers to paint an accurate picture of the British transport industry in the pre-war period. It concludes that the shipping distribution in 1910 was fifty-nine percent coastal; thirty-nine percent rail, and two percent canal - and insists that coastal and canal shipping should not be paired together when discussing the rise of the railway as they were fundamentally distinct.
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"AIDS and Beyond: Defining the Rules for Viral Traffic." In AIDS, 23–48. University of California Press, 1992. http://dx.doi.org/10.1525/9780520912441-002.
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Akhter, Shamim, Rahatur Rahman, and Ashfaqul Islam. "Neural Network (NN) Based Route Weight Computation for Bi-Directional Traffic Management System." In Deep Learning and Neural Networks, 750–65. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0414-7.ch042.
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Low-cost, flexible, easily maintainable and secure traffic management support systems are in demand. Internet-based real time bi-directional communication provides significant benefits to monitor road traffic conditions. Dynamic route computation is a vital requirement to make the traffic management system more realistic and reliable. Therefore, an integrated approach with multiple data feeds and Backpropagation (BP) Neural Network (NN) with Levenberg-Marquardt (LM) optimization is applied to predict the road weights. The results indicate that the proposed traffic system/tool with NN based dynamic weights computation is much more effective to find the optimal routes. The BP NN with LM optimization achieves 96.67% accuracy.
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Gemie, Sharif, and Brian Ireland. "The hippie as tourist." In The Hippie Trail. Manchester University Press, 2017. http://dx.doi.org/10.7228/manchester/9781526114624.003.0004.
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The chapter starts by considering some travel films produced by travellers: it notes how similar these travellers look to ordinary tourists. Differences between tourists and travellers are then considered: autonomy and authenticity seem to be the vital distinctions. By the 1970s, the majority of hippy trail travellers went to the East by coach: were they just tourists? Were the independent travellers, who went by car, train and by hitch-hiking so different? Certainly, the independent travellers frequently scorned the coach-passengers as tourists. We argue that the differences between independent travellers and coach-passengers was not as great as many assumed, and that—while there were some important similarities between travellers and tourists—the hippy trail travellers did create a distinctive form of travel of their own.
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Jamal, Arshad, Hassan M. Al-Ahmadi, Farhan Muhammad Butt, Mudassir Iqbal, Meshal Almoshaogeh, and Sajid Ali. "Metaheuristics for Traffic Control and Optimization: Current Challenges and Prospects." In Search Algorithm - Essence of Optimization [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99395.
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Intelligent traffic control at signalized intersections in urban areas is vital for mitigating congestion and ensuring sustainable traffic operations. Poor traffic management at road intersections may lead to numerous issues such as increased fuel consumption, high emissions, low travel speeds, excessive delays, and vehicular stops. The methods employed for traffic signal control play a crucial role in evaluating the quality of traffic operations. Existing literature is abundant, with studies focusing on applying regression and probability-based methods for traffic light control. However, these methods have several shortcomings and can not be relied on for heterogeneous traffic conditions in complex urban networks. With rapid advances in communication and information technologies in recent years, various metaheuristics-based techniques have emerged on the horizon of signal control optimization for real-time intelligent traffic management. This study critically reviews the latest advancements in swarm intelligence and evolutionary techniques applied to traffic control and optimization in urban networks. The surveyed literature is classified according to the nature of the metaheuristic used, considered optimization objectives, and signal control parameters. The pros and cons of each method are also highlighted. The study provides current challenges, prospects, and outlook for future research based on gaps identified through a comprehensive literature review.
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Blowers, Paul M. "The Theological Scope of Early Christian Tragical Vision." In Visions and Faces of the Tragic, 219–53. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198854104.003.0007.
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This last full chapter confirms, first of all, that tragical vision and mimesis constituted a theological artform in early Christian literature, whereby literary, rhetorical, and dramatic artistry were vital to the eminently theological interests of patristic tragical visionaries and not mere artifices. The “theodramatic” interpretive paradigm of the modern theologian Hans Urs von Balthasar is introduced as a lens through which to reevaluate the compatibility of theology and tragedy in early Christian authors. Other modern Christian tragical visionaries besides Balthasar are also brought into “conversation” with patristic interpreters of the tragic character of creaturely existence, in an effort to demonstrate the theological intelligence and accountability of early Christian tragical mimesis in its various forms, and to highlight the criteria by which “the tragic” has come to be identified in the Christian tradition. It is shown that patristic interpreters often played up human experience of intractable evil and “fateful” suffering in order, paradoxically, to enhance the depths of the divine wisdom and providence operative in creation. Tragical mimesis ultimately integrated “dark” comedy in dramatizing the “folly” of the economy of salvation.
Conference papers on the topic "Trafic viral"
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Willis, P. J. "Emerging (IP) network traffic measurements and QoS implications." In IEE Seminar Telecommunications Quality of Service (QoS): Vital Ingredient for Success. IEE, 2003. http://dx.doi.org/10.1049/ic:20030200.
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Erdmann, Jakob, Robert Oertel, and Peter Wagner. "VITAL: A Simulation-Based Assessment of New Traffic Light Controls." In 2015 IEEE 18th International Conference on Intelligent Transportation Systems - (ITSC 2015). IEEE, 2015. http://dx.doi.org/10.1109/itsc.2015.12.
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Georgiadis, Sofia K., and Andrew Comba. "Enterprise Architecture: System and Management Framework for NYCT Vital Systems." In 2013 Joint Rail Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/jrc2013-2420.
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The concept of operations for NYCT systems is changing as a result of Automatic Train Supervision (ATS) Communications-Based Train Control (CBTC), and Solid State Interlocking (SSI) deployment. Train dispatchers are dealing with a higher degree of automation with ATS systems; and similarly, train operators are adjusting to a split between automated and manual processes with CBTC systems. The emerging CBTC and SSI systems are becoming Information Technology (IT) infrastructure and digital-control based. While CBTC is increasing the overall safety of the signaling system, it is also increasing system complexity, especially from an analysis point of view. These issues are addressed at NYCT by the implementation of DoDAF, which the U.S. Department of Defense Architecture Framework, an Enterprise Architecture. This paper discusses VSI’s application of DoDAF with a focus on the safety certification mission. It begins with an overview of DoDAF, followed by a description of Views and Product-models, the building blocks of DoDAF. Each section presents a high-level description of each View, along with exemplary Product-model descriptions, 1 or 2 per View. In addition, two system capability requirements, Safe Train Separation and Control Speed to Restriction Limits, are examined and mapped throughout the model.
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Wang, Zezhou, Xiang Liu, Yongxin Wang, Chaitanya Yavvari, Matthew Jablonski, Duminda Wijesekera, Brian Sykes, and Keith Holt. "Cyber Security Analysis for Advanced Train Control System (ATCS) in CTC Systems: Concepts and Methods." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1236.
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Advanced Train Control System (ATCS) is a proprietary network protocol that expands the functionality and efficiency of Centralized Traffic Control (CTC) systems, by using radio communications (radio code line) for message delivery. However, end-to-end cyber security issues were not considered during initial design of ATCS in the 1980s. Meanwhile, the landscape of cyber-physical threats and vulnerabilities has changed dramatically over the last three decades. Even though cutting-edge systems like Positive Train Control (PTC) have adopted security properties such as integrity check and encryption methods, major railroads in North America still deploy legacy ATCS standards to maintain their individual CTC system. This paper first illustrated the background and general specifications of ATCS applications in North American railroads. The research team has noticed that few studies have systematically analyzed this topic since the emergence of ATCS, though its applications are still prevailing in the industry. Divided by both vital and non-vital operational scenarios, this paper presented case studies for ATCS-related vulnerabilities. We used a sender-receiver sequencing-based analysis and proposed a consequence-based simulation model to identify and further evaluate the cyber and physical risks under potential cyber-attacks. For the identified risk, the paper evaluated the likelihood based on the practical operational sequences, and recommended potential countermeasures for the industry to improve the security over the specific case. The research concluded that the fail-safe design in the ATCS systems would prevent the exploiting known security vulnerabilities which could result in unsafe train movements. However, the service disruptions under certain speculated attacks need further evaluation. At the end of this paper, we discussed our ongoing work for disruption evaluation in the wake of successful cyber attacks.
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Alvarez-Legazpi, Paula, Marta Vargas-Mun˜oz, Jose´ Conrado Marti´nez-Acevedo, Joaqui´n Botella-Malago´n, and Manuel Rodri´guez-Ferna´ndez. "Cross Wind Protection Systems for High Speed Railway Lines." In 2010 Joint Rail Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/jrc2010-36112.
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Higher operating rail speeds and lighter rolling stock means that cross wind, a factor that had not been considered for railway operations until recent times, has acquired vital importance in keeping adequate safety levels for railway transport of passengers. The overturn risk for a train circulating on a high speed line is determined by three key issues: • TRAIN: its aerodynamic and dynamic characteristics. • LINE: radius, azimuth, type of infrastructure, etc. • WIND: speed and angle with the train: – Wind statistics at the cross wind detection stations. – Wind models with spatial extrapolation for estimating average and actual wind on each section of the line. – Temporal forecast models at the cross wind detection stations. The combination of a certain rail line and a specific vehicle allows the determination of the criticality of each site. Once the authoritative safety target has been defined, according to this overturn risk, the adequate operating procedures must be defined. There are three possible types of protection systems: • Passive protection: protection walls or wind screens. • Active protection: short term (minutes) wind alert systems that impose restrictions to train speed when strong cross wind conditions are predicted. • Special procedures to regulate railway traffic under critical wind conditions. This paper presented hereby describes the studies to determine the susceptible sections to be protected, focus afterwards, specifically on active protection systems themselves, and main actions for its implementation.
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Hatchwell, Luke, Adam Collison, Nathan W. Bartlett, Sebastian L. Johnston, Paul S. Foster, Ana P. Siqueira, and Joerg Mattes. "TRAIL Regulates Inflammatory And Anti-Viral Responses To Rhinovirus And Rhinovirus-Induced Exacerbation Of Asthma." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a5395.
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Atanassov, Ivan, C. Tyler Dick, and Christopher P. L. Barkan. "Siding Spacing and the Incremental Capacity of the Transition From Single to Double Track." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3831.
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The North American freight railroad network is projected to experience rising transportation demand in the coming decades, leading to increased congestion along many rail corridors. Increased interest in expanded passenger service on shared rail corridors will also create additional capacity demand. However, the nation’s rail lines are still predominantly single track with passing sidings, making double track installation a vital capacity upgrade measure to sustain future volumes. Since increasing capacity through double track installation requires significant capital investment, the second main track must be allocated along a line in an optimal manner to provide maximum return on investment. An approach of investing in the least costly segments first may yield good results, but only if the benefits for each segment are equal. This research seeks to identify if the benefit of double track varies between bottleneck segments, and if there are compounding benefits of double track between adjacent passing sidings. Previous research has explored the allocation of double track on an idealized line with evenly spaced passing sidings. Due to numerous physical and engineering constraints, existing lines often exhibit a mixture of siding spacing with single-track bottleneck sections of varying length. To investigate the incremental capacity of adding double-track segments to a route with variable siding spacing, several build-out strategies are tested on a representative subdivision under random, mixed freight and passenger traffic via Rail Traffic Controller simulation software. The presented results highlight the most effective method, based on train delay, of incremental single to double track expansion and the potential differences in benefit between strategies. The linear delay reduction characteristics of single-to-double track mainlines vary based on the initial spatial arrangement of passing sidings and amount of second main track installed. These results further the understanding of relationships between infrastructure location and freight delay, thereby serving as a guideline for the sustainable expansion of existing rail corridors in anticipation of future demands. While railroads must consider many factors in selecting capital expansion projects, these guidelines can streamline the decision process by helping to quickly identify the projects with the most potential for more detailed engineering evaluation. The methodology presented can eventually be incorporated into analyzing the progressions from double to triple track lines.
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Mgebrishvili, Nikolozi. "Multifunctional Sensor-Based Monitoring System for Identifying Vehicle Characteristics." In IEEE/ASME/ASCE 2008 Joint Rail Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/jrc2008-63041.
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The intensification of investments into international transportation and the resulting intense growth of traffic volume and speed of railroad consists predetermines the need for increased safety and reliability of railroad operation. Current safety requirements revealed the urgent need for monitoring safety of rolling stock. The author designed a multifunctional wayside monitoring system that allows to identify the type and speed of passing vehicles, count the number of axles in the consist, and also determine the condition of car wheels and axles that may potentially present the risk to safe operations. The monitoring system is based on the use of intelligent sensors. Four such sensors are placed along the rail. The number of sensors is driven by the different distances between axles for commuter, passenger and freight trains operated in the countries of Former Soviet Union. For a given direction of the train the distance between the first sensor and the following other three sensors corresponds to the distances between axles of different types of vehicles. The electrical signals generated in each sensor are registered in the computer-based system that is located nearby and is hard-wired with the sensors. The computation system keeps count of number of axles passed, and computes the speed of the train. At the same time, the analog signals from the sensors, the magnitude of which represents the magneto-inductive characteristics of the wheel set depending on the state of their wear, are processed by the diagnostic system that determines the level of wheel wear. A special algorithm, developed by the author is used for identifying a type of the wheel wear. The system developed by the author is unique. It is patented in Russia and Georgia. There are no analogous technical solutions for the system to perform the named above multiple tasks. The monitoring system can be used for train location determination, for wayside diagnostics of rolling stock, for identification the type of vehicles and monitoring their movements in tunnels, for controlling the speed of vehicles, especially on steep descents, and for identification of the type and amount of passing vehicles in yards, repair facilities, depots and sidings. Equipping certain segments of railroad tracks with such monitoring devices will increase the effectiveness of railroad operation since the most vital characteristic of the passing vehicles will be monitored, which would allow to prevent potential accidents.
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Thurston, David F. "The Next Generation of Train Control for Canadian Heavy Haul Systems." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8063.
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Abstract Heavy Haul Rail Transport in Canada has not advanced as in other countries. This gives these railways a chance to leap over intermediate technology in Train Control, Asset Management and levels of RAMS not offered in previous designs. Train Control is part of a System of Systems (SoS) that provides the basis of safety for operations, while allowing other non-vital systems to be implemented cheaper and faster than systems currently being modified to perform these tasks. This paper performs several tasks. First, it will update the reader on work being performed under the auspices of the Railway Association of Canada for Enhanced Train Control, and then it will describe how Train Control will interact with other systems to provide the overall functionality for safe train movement. Finally, the base requirements for a Train Control System meeting the requirements for Enhanced Train Control will be described. The initial concepts and designs will be presented to show how the requirements will be met. In addition, the pilot project that is underway for proof of concept and operational readiness will be detailed. Test cases will be illustrated and portions of an Operational Concept, Requirements Analysis and Form Fit ad Function (F3) specifications will be documented. All of this will be the stepping stone for other systems to lead in advanced functionality and operation on Canadian Railways of the future.
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Ku, Bih-Yuan. "Augmentation of Level Crossing Safety Using Real-Time Video and Numerical Warning System." In 2010 Joint Rail Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/jrc2010-36136.
Full textAbstract:
Official statistics showed that more than half of level crossing accidents in Taiwan were caused by intrusion of road users violating the right-of-way of the railroad. Thus it is critical that addition measures be developed to prevent or mitigate the seriousness of intrusion incidences even though many warning facilities are already in place. In this paper we propose to use real-time crossing cite image to provide train drivers with more vital information than alarm signals. In addition, we also take advantage of the radio link capacity to display numerical information of train distance on the fly to deter potential intrusion attempts. The result of this project can be used as reference design for the augmentation of level crossing safety of rail systems facing similar intrusion problems.
Reports on the topic "Trafic viral"
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Chiavassa, Nathalie, and Raphael Dewez. Technical Note on Road Safety in Haiti. Inter-American Development Bank, January 2021. http://dx.doi.org/10.18235/0003250.
Full textAbstract:
The IDB has been a predominant partner supporting Haiti development efforts for many years. Nowadays, the IDB is the main source of investment for the country. Considering the vital weight of road transport sector in the socio-economy of the country, the IDB has concentrated a large part of investment efforts in rehabilitating and improving national road infrastructures. In the same time, a rapid increase of motorization and relatively higher speeds have contributed to increasing the number of traffic fatalities and injuries. In 2017, road injuries were the fifth cause of mortality in Haiti. The Road Safety situation of the country is preoccupying with many Vulnerable Road Users involved, in particular pedestrians and motorcyclists. The country is facing multi-sector challenges to address this Road Safety situation. Despite recent efforts, high political will has not been continuous in promoting a multi-sector coordination and the success of technical efforts remained mitigated over the last years. Road user awareness is still weak in the country. Risk factors include dangerous driving, bad safety conditions of vehicles, together with limited law enforcement and poor maintenance of safety devices on the roads. In this context, the Road Safety situation of the country may be getting worse in the coming years if no action is taken. However, the new Decade provides with a unique opportunity to achieve Sustainable Development Goals (SDGs) including significant progress in reducing the burden of traffic crashes. The IDB has already initiated vital investments in modernizing crash data collection, promoting institutional dialogue and supporting capacity building in the area of Road Safety. Future actions to address Road Safety challenges in Haiti in the framework of the five UN five pillars would require a range of investments in the area of political commitment, institutional coordination and technical efforts. A change of political paradigm from making roads for travelling faster to making roads safer for all users is highly needed at national level. This technical note on Road Safety in Haiti present the current situation of the country and provides with recommendations for future actions on Road Safety.