94 research outputs found
La hache de Marignane (Bouches-du-RhĂŽne) et la typologie des haches du type de Boismurie Ă lâĂąge du Bronze moyen
Ă la faveur de la dĂ©couverte rĂ©cente dâune nouvelle piĂšce Ă proximitĂ© de l'Ă©tang de Berre, sur la commune de Marignane, les auteurs proposent une refonte de la typologie des haches des types Boismurie de Abels, Castanet de Chardenoux et Courtois. Une nouvelle classification reprenant deux des variantes classiques aboutit Ă isoler 6 formes diffĂ©rentes. Elle se fonde Ă la fois sur des critĂšres morphologiques et mĂ©triques. La rĂ©partition gĂ©ographique des types conduit Ă l'hypothĂšse de productions dont la rĂ©gion d'origine peut ĂȘtre postulĂ©e pour la plupart d'entre eux. Les diffĂ©rentes structures gĂ©ographiques de rĂ©partition et de diffusion sont ensuite confrontĂ©es Ă la localisation des principaux dĂ©pĂŽts de la mĂȘme pĂ©riode, Ă la fin du Bronze moyen (BzC2). Deux zones pivots sont identifiĂ©es, dans la rĂ©gion lyonnaise et dans la partie nord du grand delta du RhĂŽne. Pour conclure, la part des piĂšces qui a pu ĂȘtre qualifiĂ©e dâimportations Ă porter au crĂ©dit dâateliers ou dâartisans ambulants nord-ouest alpins doit ĂȘtre nettement relativisĂ©e.Due to the recent discovery of a new object near the Etang de Berre, in the commune of Marignane, the authors propose a reassessment of the typology of Abels (Boismurie axe type) and those of Chardenoux and Courtois (Castanet axe type). A new classification reconsiders two of the traditional types, and enables us to identify six different forms. This is based upon morphological and metric criteria. The geographical distribution of these types leads us to suggest the production area for the majority of them. The various zones of distribution and diffusion are then considered with the distributions of the principal deposits from the same period (the end of the Middle Bronze Age (BzC2)). Two core zones are identified, one around the Lyon area, and the other in the northern part of the Rhone delta. To conclude, it is important to put into perspective the proportion of the material that can be classified as imports produced by workshops, or travelling artisans from the northwestern Alps
Approche Bayes-Markov et restauration d'images scintigraphiques
Les images scintigraphiques sont utilisées dans nombreux domaines tels que la médecine nucléaire, le contrÎle non destructif. Cependant, elles sont de qualité trÚs médiocre à cause de plusieurs sources de dégradation. Nous proposons une restauration basée sur l'approche Bayes-Markov. La détection de discontinuités et la restauration des zones homogÚnes sont réalisées efficacement par un modÚle markovien avec processus de ligne implicite. La qualité des images restaurées est mise en évidence par les mesures du contraste autour des transitions et d'uniformité dans les régions homogÚnes en comparaison avec deux autres méthodes existantes
Quantum confinement effects in Pb Nanocrystals grown on InAs
In the recent work of Ref.\cite{Vlaic2017-bs}, it has been shown that Pb
nanocrystals grown on the electron accumulation layer at the (110) surface of
InAs are in the regime of Coulomb blockade. This enabled the first scanning
tunneling spectroscopy study of the superconducting parity effect across the
Anderson limit. The nature of the tunnel barrier between the nanocrystals and
the substrate has been attributed to a quantum constriction of the electronic
wave-function at the interface due to the large Fermi wavelength of the
electron accumulation layer in InAs. In this manuscript, we detail and review
the arguments leading to this conclusion. Furthermore, we show that, thanks to
this highly clean tunnel barrier, this system is remarkably suited for the
study of discrete electronic levels induced by quantum confinement effects in
the Pb nanocrystals. We identified three distinct regimes of quantum
confinement. For the largest nanocrystals, quantum confinement effects appear
through the formation of quantum well states regularly organized in energy and
in space. For the smallest nanocrystals, only atomic-like electronic levels
separated by a large energy scale are observed. Finally, in the intermediate
size regime, discrete electronic levels associated to electronic wave-functions
with a random spatial structure are observed, as expected from Random Matrix
Theory.Comment: Main 12 pages, Supp: 6 page
In Vivo Activation of cAMP Signaling Induces Growth Arrest and Differentiation in Acute Promyelocytic Leukemia
Differentiation therapy for acute myeloid leukemia uses transcriptional modulators to reprogram cancer cells. The most relevant clinical example is acute promyelocytic leukemia (APL), which responds dramatically to either retinoic acid (RA) or arsenic trioxide (As2O3). In many myeloid leukemia cell lines, cyclic adenosine monophosphate (cAMP) triggers growth arrest, cell death, or differentiation, often in synergy with RA. Nevertheless, the toxicity of cAMP derivatives and lack of suitable models has hampered trials designed to assess the in vivo relevance of theses observations. We show that, in an APL cell line, cAMP analogs blocked cell growth and unraveled As2O3-triggered differentiation. Similarly, in RA-sensitive or RA-resistant mouse models of APL, continuous infusions of 8-chloro-cyclic adenosine monophosphate (8-Cl-cAMP) triggered major growth arrest, greatly enhanced both spontaneous and RA- or As2O3-induced differentiation and accelerated the restoration of normal hematopoiesis. Theophylline, a well-tolerated phosphodiesterase inhibitor which stabilizes endogenous cAMP, also impaired APL growth and enhanced spontaneous or As2O3-triggered cell differentiation in vivo. Accordingly, in an APL patient resistant to combined RAâAs2O3 therapy, theophylline induced blast clearance and restored normal hematopoiesis. Taken together, these results demonstrate that in vivo activation of cAMP signaling contributes to APL clearance, independently of its RA-sensitivity, thus raising hopes that other myeloid leukemias may benefit from this therapeutic approach
Combinations of single-top-quark production cross-section measurements and vertical bar f(LV)V(tb)vertical bar determinations at root s=7 and 8 TeV with the ATLAS and CMS experiments
This paper presents the combinations of single-top-quark production cross-section measurements by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at = 7 and 8 TeV corresponding to integrated luminosities of 1.17 to 5.1 fb(-1) at = 7 TeV and 12.2 to 20.3 fb(-1) at = 8 TeV. These combinations are performed per centre-of-mass energy and for each production mode: t-channel, tW, and s-channel. The combined t-channel cross-sections are 67.5 +/- 5.7 pb and 87.7 +/- 5.8 pb at = 7 and 8 TeV respectively. The combined tW cross-sections are 16.3 +/- 4.1 pb and 23.1 +/- 3.6 pb at = 7 and 8 TeV respectively. For the s-channel cross-section, the combination yields 4.9 +/- 1.4 pb at = 8 TeV. The square of the magnitude of the CKM matrix element V-tb multiplied by a form factor f(LV) is determined for each production mode and centre-of-mass energy, using the ratio of the measured cross-section to its theoretical prediction. It is assumed that the top-quark-related CKM matrix elements obey the relation |V-td|, |V-ts| << |V-tb|. All the |f(LV)V(tb)|(2) determinations, extracted from individual ratios at = 7 and 8 TeV, are combined, resulting in |f(LV)V(tb)| = 1.02 +/- 0.04 (meas.) +/- 0.02 (theo.). All combined measurements are consistent with their corresponding Standard Model predictions.Peer reviewe
Adam Smith et la physique de Newton
In most of Smith's writings we find references to the natural philosophy of Newton. Beyond the use of Newtonian concepts and laws to deal with specific issues, we would like to focus on the relationship between the Smithian representation of the social world and the Newtonian representation of the natural world. Smith relies on Newton to get himself involved in major policy debates that shape the intellectual life of Western Europe from Hobbes through Locke, Shaftesbury, Mandeville, Hutcheson, Hume and Rousseau. Newtonian physics allows Smith to advocate an approach to social and political life freed from social contract, in contrast with Locke. Nourished by chosen references to physics and physicists from Antiquity to 18th century, Smithâs use of Newtonian physics, together with references to Lockeâs philosophy, lead Smith to reject both Cartesian theology and Cartesian physics
Adam Smith et la physique de Newton
Dans la plupart des Ă©crits de Smith nous trouvons des rĂ©fĂ©rences Ă la philosophie naturelle de Newton. Au-delĂ du simple usage de concepts et de lois newtoniens pour traiter de questions particuliĂšres, il faut surtout retenir la parentĂ© entre la reprĂ©sentation du monde social chez Smith et la reprĂ©sentation du monde naturel chez Newton. Smith sâappuie sur Newton pour sâimpliquer dans les grands dĂ©bats politiques qui rythment la vie intellectuelle de lâEurope occidentale depuis Hobbes en passant par Locke, Shaftesbury, Mandeville, Hutcheson, Hume et Rousseau. La physique de Newton permettra Ă Smith de dĂ©fendre une approche de la vie sociale et politique Ă©mancipĂ©e de tout contrat social, auquel se rattachait encore un auteur libĂ©ral comme Locke. Les rĂ©fĂ©rences de Smith Ă Newton sâappuient sur une bonne connaissance des travaux des physiciens depuis lâAntiquitĂ© jusquâau XVIIIĂšme siĂšcle. Elles sâexpliquent aussi par le contexte intellectuel britannique de lâĂ©poque caractĂ©risĂ© par la reconnaissance des travaux de Locke dans le champ de la philosophie et de ceux de Newton dans celui de la physique. Elles conduiront Smith Ă rejeter tant la physique cartĂ©sienne que sa thĂ©ologie.In most of Smith's writings we find references to the natural philosophy of Newton. Beyond the use of Newtonian concepts and laws to deal with specific issues, we would like to focus on the relationship between the Smithian representation of the social world and the Newtonian representation of the natural world. Smith relies on Newton to get himself involved in major policy debates that shape the intellectual life of Western Europe from Hobbes through Locke, Shaftesbury, Mandeville, Hutcheson, Hume and Rousseau. Newtonian physics allows Smith to advocate an approach to social and political life freed from social contract, in contrast with Locke. Nourished by chosen references to physics and physicists from Antiquity to 18th century, Smithâs use of Newtonian physics, together with references to Lockeâs philosophy, lead Smith to reject both Cartesian theology and Cartesian physics
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