Choix des lieux de résidence et de travail et comportement de transport dans le modèle M.A.T.I.S.S.E.: Analyse rétrospective sur longue période dans le cas d'un pays tel que la France

247 p.M.AT.I.S.S.E. is a model describing the behaviour of households, in order to analyse the past or future evolution of car ownership and of short or long distance mobility, as well as of land use to a certain extent. Considering the different types of households and the trips made by their members, not only is it possible to describe how the travelers decide to make a given journey or not and - if so - how the journey is made, but also to explain the choice of residence and work places and the choice of car ownership, with all the interactions existing between those choices and the urban/interurban mobility of the individuals. This applies to socio-economic contexts and transportation supplies which characteristics may be real (for past analysis) or hypothetical (for prospective exercises). After the model description, the report gives the results obtained when the model is applied to a territory like France for the 1975-2007 period. The conclusion emphasizes the difficulty in quantifying the importance of transport services in the households' choice for their place of residence.M.A.T.I.S.S.E. est un modèle de comportement des ménages, destiné à l'analyse rétrospective ou prospective de l'équipement automobile et de la mobilité à courte et à longue distance, ainsi que - dans une certaine mesure - de l'occupation du sol. Considérant les différents types de ménages et les déplacements des individus qui composent ces ménages, on peut représenter non seulement le choix des voyageurs d'effectuer ou non un voyage donné et - si oui - selon quelle modalité, mais aussi le choix des lieux de résidence et de travail et de l'équipement automobile par les ménages, avec tous les liens qui existent entre les décisions prises et la mobilité des individus, tant urbaine qu'interurbaine. Et ceci, pour des contextes socio-économiques et des situations d'offre de transport de caractéristiques réelles (pour la rétrospective) ou hypothétiques (pour la prospective). Après la description du modèle, le document donne les résultats de son application à un pays qui présente une grande similitude avec la France pour la période 1975-2007. Il souligne en conclusion la difficulté qu'il y a à quantifier le poids des dessertes de transport au sein du processus de choix des lieux de résidence par les ménages

Localisation des activités, choix des lieux de résidence et de travail et comportement de mobilité dans le modèle M.A.T.I.S.S.E.: Application rétrospective sur longue période au cas de l'Ile-de-France

M.AT.I.S.S.E. is a model describing the behaviour of households, in order to analyse the past or future evolution of car ownership and of short or long distance mobility, as well as of land use to a certain extent. Considering the different types of households and the trips made by their members, not only is it possible to describe how the travelers decide to make a given journey or not and - if so - how the journey is made, but also to explain the choice of residence and work places and the choice of car ownership, with all the interactions existing between those choices and the urban/interurban mobility of the individuals. It is also possible to describe in parallel how the workplaces are located. This applies to socio-economic contexts and transportation supplies which characteristics may be real (for past analysis) or hypothetical (for prospective exercises). After the model description, the report gives the results obtained when the model is applied to a territory like Ile-de-France for the 1975-2007 period.M.A.T.I.S.S.E. est un modèle de comportement des ménages, destiné à l'analyse rétrospective ou prospective de l'équipement automobile et de la mobilité à courte et à longue distance, ainsi que - dans une certaine mesure - de l'occupation du sol. Considérant les différents types de ménages et les déplacements des individus qui composent ces ménages, on peut représenter non seulement le choix des voyageurs d'effectuer ou non un voyage donné et - si oui - selon quelle modalité, mais aussi le choix des lieux de résidence et de travail et de l'équipement automobile par les ménages, avec tous les liens qui existent entre les décisions prises et la mobilité des individus, tant urbaine qu'interurbaine. On peut également, en parallèle, représenter les phénomènes de localisation des activités, et notamment des emplois. Et ceci, pour des contextes socio-économiques et des situations d'offre de transport de caractéristiques réelles (pour la rétrospective) ou hypothétiques (pour la prospective). Après la description du modèle, le document donne les résultats de son application à une région qui présente une grande similitude avec l'Ile-de-France pour la période 1975-2007

Electrons, gammas and pi0, in heavy liquid bubble chambers

The aim of this paper is to give necessary basis for understanding how to measure, calculate and use electronic trajectories and how to combine them in gamma or pi

A half a century of measuring ungulate body condition using indices: is it time for a change?

From a literature review of five wildlife ecology journals since 1937, we document how using indices to monitor ungulate body condition is common practice, with the kidney fat index (KFI = weight of fat around the kidneys/weight of kidneys without fat × 100) as the favoured tool (82% of studies). In this context, we highlight the problems of using indices when underlying statistical assumptions are not met (isometry, parallel slopes between treatments). We show, with real and simulated data for two cervids with contrasting fat storage strategies, how results from analysis of variance of KFI values differ from analysis of covariance (ANCOVA) of raw data. We conclude that the KFI is affected by the restrictions typically associated with derived index values, and as a consequence, statistical analysis of the KFI could generate spurious results leading to erroneous interpretations concerning variation in body condition of ungulate populations. Thus, we recommend analysing fat weight as an untransformed variable in ANCOVA (kidney weight as covariate) to describe body condition variation in ungulates

Replacement of His23 by Cys in a zinc finger of HIV-1 NCp7 led to a change in 1H NMR-derived 3D structure and to a loss of biological activity

AbstractThe nucleocapsid protein NCp7 of human immunodeficiency virus type 1 (HIV-1), which is necessary for the formation of infectious virions, contains two zinc fingers of the Cys-X2-Cys-X4-His-X4-Cys form. To elucidate the importance of this particular motif, well conserved in retroviruses and retroelements, we substituted the histidine residue by a cysteine in the first zinc binding domain 13VKCFNCGKEGHTARNCRA30. The structures of the mutated and native zinc complexed peptides were studied by two-dimensional 600 MHz 1H nuclear magnetic resonance (NMR) in aqueous solution. The nuclear Overhauser effects were used as constraints to determine the solution structures using DIANA software followed by AMBER energy refinement. The results show that native and mutant peptides fold into non-identical three-dimensional structures, probably accounting for the loss of retrovirus infectivity following the His-Cys point mutation

Modélisation du mouvement des chevreuils dans un paysage bocager simulé : premiers résultats, projets

Les tiques, dont Ixodes ricinus, espèce la plus répandue en Europe, sont vecteurs de nombreux agents pathogènes, protozoaires, bactéries ou virus, qui peuvent être responsables de maladies touchant l’Homme (Borreliose de Lyme) ou l’animal(babésiose bovine). En vue d’identifier les zones à risque vis-à-vis de ces maladies, il est important de connaître la distribution spatiale des tiques. Cette distribution dépend d’une part des conditions locales de température et d’humidité, d’autre part des mouvements des hôtes des tiques(Estrada-Peña, 2002). Les chevreuils sont notamment reconnus pour influencer fortement la densité de tiques(Ruiz-Fons et Gilbert 2010) et se déplacer sur de longues distances. Dans le cadre de l’estimation spatiale des risques, il est nécessaire de disposer d’un modèle de déplacement des hôtes en fonction des caractéristiques du paysage, dont le développement n’a pas été réalisé à ce jour. Dans un premier temps, une approche théorique a été privilégiée. Un modèle du paysage a été développé via une tesselation de Voronoï et un processus de marquage. Au sein de ce paysage modélisé, le mouvement du chevreuil est modélisé par des équations différentielles stochastiques. Ce mouvement se décompose donc en deux termes : un de dérive, qui dépend d’une fonction de potentiel reliée aux différents habitats qui composent le paysage, et un terme de diffusion. A partir d’une première fonction potentielle, il est donc possible de simuler le déplacement d’un individu dans un paysage modélisé. Les développements actuels visent dans un premier temps à tester différentes fonctions de potentiel en fonction de nos connaissances sur le comportement du chevreuil. L’étape suivante consistera à développer des méthodes d’inférence afin d’estimer les paramètres à partir de données simulées ou observées. Par la suite le prototype obtenu pourra être utilisé pour tester l’influence des caractéristiques du paysage sur le mouvement des chevreuils. Enfin, un couplage avec un modèle de dynamique de population de tiques (Hoch et al, 2010) fournira des aires de répartition simulées des vecteurs

Mechanisms of HIV-1 Nucleocapsid Protein Inhibition by Lysyl-Peptidyl-Anthraquinone Conjugates

The Nucleocapsid protein NCp7 (NC) is a nucleic acid chaperone responsible for essential steps of the HIV-1 life cycle and an attractive candidate for drug development. NC destabilizes nucleic acid structures and promotes the formation of annealed substrates for HIV-1 reverse transcription elongation. Short helical nucleic acid segments bordered by bulges and loops, such as the Trans-Activation Response element (TAR) of HIV-1 and its complementary sequence (cTAR), are nucleation elements for helix destabilization by NC and also preferred recognition sites for threading intercalators. Inspired by these observations, we have recently demonstrated that 2,6-disubstituted peptidylanthraquinone-conjugates inhibit the chaperone activities of recombinant NC in vitro, and that inhibition correlates with the stabilization of TAR and cTAR stem-loop structures. We describe here enhanced NC inhibitory activity by novel conjugates that exhibit longer peptidyl chains ending with a conserved Nterminal lysine. Their efficient inhibition of TAR/cTAR annealing mediated by NC originates from the combination of at least three different mechanisms, namely, their stabilizing effects on nucleic acids dynamics by threading intercalation, their ability to target TAR RNA substrate leading to a direct competition with the protein for the same binding sites on TAR, and, finally, their effective binding to the NC protein. Our results suggest that these molecules may represent the stepping-stone for the future development of NC-inhibitors capable of targeting the protein itself and its recognition site in RNA

Cold Shock and Cold Acclimation Proteins in the Psychrotrophic Bacterium Arthrobacter globiformis SI55

The psychrotrophic bacterium Arthrobacter globiformis SI55 was grown at 4 and 25 degrees C, and the cell protein contents were analyzed by two-dimensional electrophoresis. Cells subjected to cold shocks of increasing magnitude were also analyzed. Correspondence analysis of protein appearance distinguished four groups of physiological significance. Group I contained cold shock proteins (Csps) overexpressed only after a large temperature downshift. Group II contained Csps with optimal expression after mild shocks. Group III contained proteins overexpressed after all cold shocks. These last proteins were also overexpressed in cells growing at 4 degrees C and were considered to be early cold acclimation proteins (Caps). Group IV contained proteins which were present at high concentrations only in 4 degrees C steady-state cells and appeared to be late Caps. A portion of a gene very similar to the Escherichia coli cspA gene (encoding protein CS7.4) was identified. A synthetic peptide was used to produce an antibody which detected a CS7.4-like protein (A9) by immunoblotting two-dimensional electrophoresis gels of A. globiformis SI55 total proteins. Unlike mesophilic microorganisms, this CS7.4-like protein was still produced during prolonged growth at low temperature, and it might have a particular adaptive function needed for balanced growth under harsh conditions. However, A9 was induced at high temperature by chloramphenicol, suggesting that CS7.4-like proteins have a more general role than their sole implication in cold acclimation processes

The conserved N-terminal basic residues and zinc-finger motifs of HIV-1 nucleocapsid restrict the viral cDNA synthesis during virus formation and maturation

Reverse transcription of the genomic RNA by reverse transcriptase occurs soon after HIV-1 infection of target cells. The viral nucleocapsid (NC) protein chaperones this process via its nucleic acid annealing activities and its interactions with the reverse transcriptase enzyme. To function, NC needs its two conserved zinc fingers and flanking basic residues. We recently reported a new role for NC, whereby it negatively controls reverse transcription in the course of virus formation. Indeed, deleting its zinc fingers causes reverse transcription activation in virus producer cells. To investigate this new NC function, we used viruses with subtle mutations in the conserved zinc fingers and its flanking domains. We monitored by quantitative PCR the HIV-1 DNA content in producer cells and in produced virions. Results showed that the two intact zinc-finger structures are required for the temporal control of reverse transcription by NC throughout the virus replication cycle. The N-terminal basic residues also contributed to this new role of NC, while Pro-31 residue between the zinc fingers and Lys-59 in the C-terminal region did not. These findings further highlight the importance of NC as a major target for anti-HIV-1 drugs