2,654 research outputs found
Quantum revival for elastic waves in thin plate
Quantum revival is described as the time-periodic reconstruction of a wave
packet initially localized in space and time. This effect is expected in
finite-size systems which exhibits commensurable discrete spectrum such as the
infinite quantum well. Here, we report on the experimental observation of full
and fractional quantum revival for classical waves in a two dimensional cavity.
We consider flexural waves propagating in thin plates, as their quadratic
dispersion at low frequencies mimics the dispersion relation of quantum systems
governed by Schr\"{o}dinger equation. Time-dependent excitation and measurement
are performed at ultrasonic frequencies and reveal a periodic reconstruction of
the initial elastic wave packet.Comment: submitted to the special issue of EPJ ST in honor of scientific
legacy of Roger Maynar
Maps, Travel and Exploration in the Middle Ages: Some Reflections about Anachronism
Abstract: How were maps conceived in the Middle Ages? Using the words âmapâ, âtravelâ and âexplorationâ, historians must be wary of anachronism. Medieval maps, like ours maps, are always materialized thought-objects and are thus interpretations of the world, inevitably variable and subject to criticism; in this respect, âmodernityâ has neither invented nor changed anything. The article addresses some anachronisms about the role of mappae mundi in mental journeys, their function in maritime travels and their role during the great âdiscoveriesâ; it claims that no other pre-modern civilization, except perhaps the Chinese, was ever so imbuedwith cartographic culture
Chet Van Duzer, Henricus Martellusâs World Map at Yale (c. 1491): Multispectral Imaging, Sources, and Influence
Revie
Maps, Travel and Exploration in the Middle Ages: Some Reflections about Anachronism
Abstract: How were maps conceived in the Middle Ages? Using the words âmapâ, âtravelâ and âexplorationâ, historians must be wary of anachronism. Medieval maps, like ours maps, are always materialized thought-objects and are thus interpretations of the world, inevitably variable and subject to criticism; in this respect, âmodernityâ has neither invented nor changed anything. The article addresses some anachronisms about the role of mappae mundi in mental journeys, their function in maritime travels and their role during the great âdiscoveriesâ; it claims that no other pre-modern civilization, except perhaps the Chinese, was ever so imbuedwith cartographic culture
Extracting (good) discourse examples from an oral specialised corpus of wine tasting interactions
International audienceThis article outlines the semi-automated extraction of dictionary examples used in the compilation of a professional online dictionary of wine tasting. Named OenoLex Bourgogne, this dictionary was started to respond to the demand for a lexicographic information tool from the French wine industry of Burgundy, the Bureau Interprofessionnel des Vins de Bourgogne
Ag2.54Tl2Mo12Se15: a new structure type containing Mo6 and Mo9 clusters
wosInternational audienceThe novel structure-type Ag2.54Tl2Mo12Se15 (silver thallium molybdenum selenide) is built up of Mo6Sei8Sea6 and Mo9Sei11Sea6 cluster units in a 1:2 ratio, which are three-dimensionally connected to form the Mo-Se network. The Ag and Tl cations are distributed in several voids within the cluster network. Three of the seven independent Se atoms and one Tl atom lie on sites with 3.. symmetry (Wyckoff sites 2c or 2d)
RĂŽle de CD47 dans lâinduction de la tolĂ©rance in vivo
La tolĂ©rance orale permet la modulation de la rĂ©ponse immunitaire Ă lâĂ©gard des antigĂšnes exogĂšnes prĂ©sents dans la lumiĂšre intestinale. Essentiels Ă lâĂ©tablissement dâune relation symbiotique entre le systĂšme immunitaire et la flore intestinale, lâinduction et le maintien de la tolĂ©rance orale reposent sur diffĂ©rents mĂ©canismes immunologiques. Parmi eux, lâinduction de cellules T rĂ©gulatrices par les cellules dendritiques et de mĂ©canismes apoptotiques. Or, la glycoprotĂ©ine membranaire CD47 est impliquĂ©e, en pĂ©riphĂ©rie, dans ces mĂ©canismes. Cependant, le rĂŽle de CD47 dans la tolĂ©rance orale nâest pas connu. Ă lâaide dâun modĂšle murin dĂ©ficient en CD47, nous avons dĂ©montrĂ© principalement, que lâabsence de CD47 est associĂ©e Ă une diminution de 50 % de la proportion de cellules dendrites myĂ©loĂŻdes CD11b+CD103- retrouvĂ©es dans les ganglions mĂ©sentĂ©riques. Suite au transfert adoptif de cellules T antigĂšnes spĂ©cifiques dans nos diffĂ©rents modĂšles expĂ©rimentaux, on a, aussi, observĂ© une diminution de 45 % de leur niveau dâactivation dans les ganglions mĂ©sentĂ©riques. MalgrĂ© les effets observĂ©s, le CD47 nâest pas impliquĂ© dans lâinduction dâune rĂ©action de tolĂ©rance orale secondaire Ă lâadministration intragastrique de fortes doses dâovalbumine. Cependant, nous avons dĂ©montrĂ© que CD47 est impliquĂ©e au niveau de la migration des cellules dendritiques de la peau et de certaines sous-populations retrouvĂ©es dans les ganglions mĂ©sentĂ©riques.Oral tolerance allows the modulation of the immune response against exogenous antigens present in the intestinal lumen. Essential to establish a symbiotic relationship between the immune system and intestinal flora, the induction and maintenance of oral tolerance rests on different immunological mechanisms. Among them, induction of regulatory T cells by dendritic cells and apoptotic mechanisms. However, the membrane glycoprotein CD47 is involved in the periphery of these mechanisms. However, the role of CD47 in oral tolerance is unknown. With a mouse model deficient in CD47, we showed mainly that the absence of CD47 is associated with a decrease of 50% in the proportion of myeloid dendritic cells CD11b+ CD103- found in the mesenteric lymph nodes. Following the adoptive transfer of antigen specific T cells in our experimental models, we also observed a decrease of 45% of their level of activation in mesenteric lymph nodes. Despite the observed effects, CD47 is not involved in the induction of oral tolerance response secondary to intragastric administration of high doses of ovalbumin. However, we have shown that CD47 is involved in the migration of dendritic cells of the skin and some sub-populations found in mesenteric lymph nodes
Les reprĂ©sentations de lâespace en Occident de lâAntiquitĂ© tardive au xvie siĂšcle
Programme de lâannĂ©e 2010-2011 : I. ReprĂ©sentations de lâespace et souverainetĂ© au Moyen Ăge. â II. Cartographie Ă grande Ă©chelle en France (Moyen Ăge â dĂ©but xvie siĂšcle)
Ă propos de la mappemonde dâEbstorf
La mappemonde du monastĂšre fĂ©minin dâEbstorf en Saxe, diversement datĂ©e dans le courant du xiiie ou du xive siĂšcle, nâest plus connue que par des fac-similĂ©s antĂ©rieurs Ă sa destruction lors de la seconde guerre mondiale. Par ses dimensions (une trentaine de feuilles de parchemin cousues ensemble mesurant au total 3,58 x 3,56 m et couvrant 12,74 mÂČ), câĂ©tait la plus grande et la plus riche des mappae mundi monumentales du Moyen Ăge. Outre des textes Ă©crits dans les parties extĂ©rieures, elle c..
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