1,020 research outputs found

    Intrinsic and Extrinsic Neuronal Mechanisms in Temporal Coding: A Further Look at Neuronal Oscillations

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    Many studies in recent years have been devoted to the detection of fast oscillations in the Central Nervous System (CNS), interpreting them as synchronizing devices. We should, however, refrain from associating too closely the two concepts of synchronization and oscillation. Whereas synchronization is a relatively well-defined concept, by contrast oscillation of a population of neurones in the CNS looks loosely defined, in the sense that both its frequency sharpness and the duration of the oscillatory episodes vary widely from case to case. Also, the functions of oscillations in the brain are multiple and are not confined to synchronization. The paradigmatic instantiation of oscillation in physics is given by the harmonic oscillator, a device particularly suited to tell the time, as in clocks. We will thus examine first the case of oscillations or cycling discharges of neurones, which provide a clock or impose a “tempo” for various kinds of information processing. Neuronal oscillators are rarely just clocks clicking at a fixed frequency. Instead, their frequency is often adjustable and controllable, as in the example of the “chattering cells” discovered in the superficial layers of the visual cortex. Moreover, adjustable frequency oscillators are suitable for use in “phase locked loops” (PLL) networks, a device that can convert time coding to frequency coding; such PLL units have been found in the somatosensory cortex of guinea pigs. Finally, are oscillations stricto sensu necessary to induce synchronization in the discharges of downstream neurones? We know that this is not the case, at least not for local populations of neurones. As a contribution to this question, we propose that repeating patterns in neuronal discharges production may be looked at as one such alternative solution in relation to the processing of information. We review here the case of precisely repeating triplets, detected in the discharges of olfactory mitral cells of a freely breathing rat under odor stimulation

    Priming DNA Replication from Triple Helix Oligonucleotides: Possible Threestranded DNA in DNA Polymerases

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    Triplex associate with a duplex DNA presenting the same polypurine or polypyrimidine-rich sequence in an antiparallel orientation. So far, triplex forming oligonucleotides (TFOs) are known to inhibit transcription, replication, and to induce mutations. A new property of TFO is reviewed here upon analysis of DNA breakpoint yielding DNA rearrangements; the synthesized sequence of the first direct repeat displays a skewed polypurine- rich sequence. This synthesized sequence can bind the second homologous duplex sequence through the formation of a triple helix, which is able to prime further DNA replication. In these case, the d(G)-rich Triple Helix Primers (THP) bind the homologous strand in a parallel manner, possibly via a RecA-like mechanism. This novel property is shared by all tested DNA polymerases: phage, retrovirus, bacteria, and human. These features may account for illegitimate initiation of replication upon single-strand breakage and annealing to a homologous sequence where priming may occur. Our experiments suggest that DNA polymerases can bind three instead of two polynucleotide strands in their catalytic centre

    Évaluation de l’insĂ©curitĂ© alimentaire dans le ComtĂ© de Sacramento

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    En 2001, environ 56 000 adultes Ă©taient considĂ©rĂ©s en situation d’insĂ©curitĂ© alimentaire dans le ComtĂ© de Sacramento. MalgrĂ© les six programmes d’aide alimentaire administrĂ©s par le gouvernement amĂ©ricain, le nombre de personnes ayant recours Ă  des structures d’aide alimentaire d’urgence n’a cessĂ© de croĂźtre durant les 20 derniĂšres annĂ©es. Notre Ă©tude a pour objectif de connaĂźtre les personnes ayant recours Ă  l’aide alimentaire d’urgence et d’évaluer l’utilisation des programmes gouvernementaux au sein du ComtĂ©. Pour cela, 338 personnes ont Ă©tĂ© interrogĂ©es dans les structures d’aide alimentaire d’urgence et des entretiens ont Ă©tĂ© effectuĂ©s avec les responsables de chaque programme gouvernemental. Notre Ă©tude montre que les programmes gouvernementaux sont sousutilisĂ©s principalement du fait du manque d’information auprĂšs des personnes Ă©ligibles et de barriĂšres telles que la difficultĂ© d’accĂ©der aux centres, les problĂšmes de langue pour de nombreux immigrĂ©s ou des lourdeurs administratives.food aid, federal food assistance programs, food security, challenges

    La dynamique de la dépression post-partum sur la socialisation de l'enfant

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    Notre mémoire se situe dans une vision compréhensive psychodynamique composée des théories interactionnistes de Georges Hébert Mead ainsi gue de la psychopathologie et de la psychodynamique du travail de Christophe Dejours. Il consiste à s'interroger sur le rÎle de la dépression maternelle en lien avec le développement et l'avenir social de l'enfant. Nous mettrons en valeur l'organisation de soins de la mÚre comme un travail qui aura des conséquences sur l'expérience et sur le développement de l'enfant. Nous montrerons d'une part que les différents types de relations que la personne a eues dans sa famille, et cela, depuis le début de sa vie, vont s'enraciner et se répéter, voire s'amplifier, dans son histoire de vie. Nous saisirons d'autre part que les conduites individuelles constituent le fruit de l'expérience issue des interactions dans la communauté que forment la mÚre et l'enfant ainsi que la résultante de l'absence de triangulation avec le pÚre

    La salle Ă  manger : naissance et adoption d’une piĂšce rĂ©servĂ©e au repas (xviie-xixe siĂšcle)

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    La naissance et l’évolution de la salle Ă  manger française s’inscrivent dans un mouvement gĂ©nĂ©ral de spĂ©cialisation des piĂšces aux xviie et xviiie siĂšcles. Jusqu’alors, les piĂšces d’habitation sont, et ce dans toutes les couches sociales, des « espaces polyvalents », oĂč seul le mobilier dĂ©termine l’usage. Ainsi, en fonction de la saison ou du nombre de convives, les lieux oĂč se tiennent les repas sont trĂšs divers : dans l’architecture des Ă©lites, la chambre, la salle ou l’antichambre peuvent trĂšs bien tenir ce rĂŽle, avant que s’impose une piĂšce spĂ©cifique, appelĂ©e « salle Ă  manger ». Le mot lui-mĂȘme est employĂ© pour la premiĂšre fois dans des sources manuscrites au dĂ©but du xviie siĂšcle. S’ensuit alors un processus d’adoption de la piĂšce assez lent qui ne se gĂ©nĂ©ralisera Ă  toutes les couches de la sociĂ©tĂ© qu’au cours des xviiie et xixe siĂšcles. Le dĂ©veloppement de cette piĂšce s’est en effet nourri d’un terreau d’évolutions architecturales et sociales trĂšs riche.The appearance and development of the dining room in France was part of a general move towards the specialisation of the use of a house’s different rooms, from the seventeenth to eighteenth centuries. Up until then, the living spaces in a dwelling, at all levels in society, were ‘polyvalent’ spaces where only the furniture denoted the use. Consequently, and according to the season or to the number of guests, the room where meals were eaten could vary. In the architecture of social elites, the bedroom or the antechamber could fulfil this dining function, before a specific room began to appear, known in French as the ‘salle Ă  manger’, the dining room. The expression appears in manuscript sources at the beginning of the seventeenth century. Subsequently, there is a gradual process of appropriation and generalisation throughout society during the eighteenth and nineteenth centuries. The development of this room is to be seen then in a rich context of social and architectural changes

    Whitehead, la NĂ©gation de l’Instant et la MĂ©canique Quantique

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    The philosophy of Nature and Time in Alfred North Whitehead (1861-1947) may not have received enough attention from scientists, particularly in France. We know that this mathematician-philosopher collaborating with Bertrand Russell in writing Principia Mathematica (1910-1913), insisted on the abstract character of space points in the foundation of geometry. From 1911 onwards, he extended this observation to the instants of time, and gradually developed a vision of the ontology of the world as a succession of "concrescences of actual entities", each of which brings with it a piece of time. These concrescences are reminiscent of the collapse of the wave function in measuring processes in quantum mechanics; as a matter of fact, Whitehead has closely followed the development of this theory, just as he has closely followed the development of the relativity theory. Furthermore, his philosophy of Nature, or following his own words his philosophy of organism, foresees a global solidarity of the actual entities which in some ways recalls quantum entanglement. This similarity and its limits are examined in more depth, and the mind-matter relations in Whitehead’s philosophy are broached. Despite its defects, Whitehead's metaphysics, especially the negation of the instant, has brought to light, in my opinion, the complexity of nature's time (with Whitehead the process), far beyond the continuous variable t of physicists. A large part of this article is based on my book Whitehead, Philosophe du Temps (Auteur, 2020).La philosophie de la Nature et du Temps chez Alfred North Whitehead (1861-1947) n’a peut-ĂȘtre pas assez retenu l’attention des scientifiques, en particulier en France. On sait que ce mathĂ©maticien-philosophe collaborant avec Bertrand Russell pour l’écriture des Principia Mathematica (1910-1913) a insistĂ© sur le caractĂšre abstrait des points d’espace dans la fondation de la gĂ©omĂ©trie. A partir de 1911, il Ă©tend cette observation aux instants de temps, et dĂ©veloppe progressivement, Ă  partir de lĂ , une vision de l’ontologie du monde comme une succession de « concrescences d’entitĂ©s actuelles » dont chacune apporte avec elle une brique de temps finie. Ces concrescences ne sont pas sans rappeler les rĂ©ductions du paquet d’ondes dans les opĂ©rations de mesure en mĂ©canique quantique ; en fait, Whitehead a suivi de prĂšs le dĂ©veloppement de cette thĂ©orie, comme il a suivi de prĂšs le dĂ©veloppement de la relativitĂ©. Par ailleurs, sa philosophie de la Nature, ou comme il le dit sa philosophie de l’organisme, prĂ©voit une solidaritĂ© globale des entitĂ©s actuelles qui par certains cĂŽtĂ©s rappelle l’intrication quantique. On examine plus en profondeur cette similaritĂ© et ses limites, et aborde les relations esprit-matiĂšre chez cet auteur. MalgrĂ© ses dĂ©fauts, la mĂ©taphysique de Whitehead, en en particulier la nĂ©gation de l’instant a mis en lumiĂšre, Ă  mon sens, la complexitĂ© du temps de la nature (chez Whitehead le process), bien au-delĂ  de la variable continue t des physiciens. Une large part de cet article est basĂ©e sur mon livre Whitehead, Philosophe du Temps (auteur, 2020, Ă  paraĂźtre)

    Patrimoines de la santé : essais de dĂ©finition – enjeux de conservation

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    Ce numĂ©ro d’In Situ. Revue des patrimoines consacrĂ© aux patrimoines de la santĂ© – le premier traitant de ce sujet – trouve son origine dans l’actualitĂ©. Les recherches sur l’architecture hospitaliĂšre se sont multipliĂ©es ces derniĂšres annĂ©es. Elles ont donnĂ© lieu Ă  deux importantes synthĂšses, celle, rĂ©gionale, publiĂ©e par le service Patrimoine et Inventaire de Bourgogne en 2011, Patrimoine hospitalier en Bourgogne, et celle, nationale, de l’Inventaire gĂ©nĂ©ral du patrimoine culturel, l’annĂ©e su..

    Linear programming can help identify practical solutions to improve the nutritional quality of food aid.

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    OBJECTIVES: To assess the nutritional quality of food aid delivered by food banks in France and to identify practical modifications to improve it. DESIGN: National-level data were collected for all food aid distributed by French food banks in 2004, and its nutrient content per 2000 kcal was estimated and compared with French recommendations for adults. Starting with the actual donation and allowing new foods into the food aid donation, linear programming was used to identify the minimum changes required in the actual donation to achieve the French recommendations. RESULTS: French food-bank-delivered food aid does not achieve the French recommendations for dietary fibre, ascorbic acid, vitamin D, folate, magnesium, docosahexaenoic acid, alpha-linolenic acid and the percentage of energy from saturated fatty acids. Linear programming analysis showed that these recommendations are achievable if more fruits, vegetables, legumes and fish were collected and less cheese, refined cereals and foods rich in fat, sugar and/or salt. In addition, new foods not previously collected are needed, particularly nuts, wholemeal bread and rapeseed oil. These changes increased the total edible weight (42%) and economic value (55%) of the food aid donation, with one-third of its edible weight coming from fruits and vegetables, one-third from staples, one-quarter from dairy products and approximately a tenth from meat/fish/eggs. CONCLUSIONS: Important changes in the types and amounts of food collected will improve the nutritional quality of food-bank-delivered food aid in France. Such changes are recommended to improve the diets of deprived French populations

    t(11;17)(p15;q21) involving the NUP98 gene is a rare event in adult acute myeloid leukemia.

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    Review on t(11;17)(p15;q21) involving the NUP98 gene is a rare event in adult acute myeloid leukemia

    del(5)(q32q33) EBF1/PDGFRB

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    Review on del(5)(q32q33) EBF1/PDGFRB fusion with clinical data and genes involved
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