540 research outputs found

    Kudla Millson lift of toric cycles and restriction of Hilbert modular forms

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    Let VV be quadratic space of even dimension and of signature (p,q)(p, q) with pq>0p \geq q > 0. We show that the Kudla-Millson lift of toric cycles - attached to algebraic tori - is a cusp form that is the diagonal restriction of a Hilbert modular form of parallel weight one. We deduce a formula relating the dimension of the span of such diagonal restrictions and the dimension of the span of toric and special cycles.Comment: v2: References added v3: We remove the unnecessary anisotropy condition for the quadratic space in section 5, that rendered Corollary 1.2.1 empt

    Diagonal restriction of Eisenstein series and Kudla-Millson theta lift

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    We consider the Kudla-Millson theta series associated to a quadratic space of signature (N,N)(N,N). By combining a `see-saw' argument with the Siegel-Weil formula, we show that its (regularized) integral along a torus attached to a totally real field of degree NN is the diagonal restriction of an Eisenstein series. It allows us to express the Fourier coefficients of the diagonal restriction as intersection numbers, which generalizes a result of Darmon-Pozzi-Vonk to totally real fields.Comment: 46 page

    El Loira : els conflictes per la utilització del riu

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    El paisatge, confrontació d'un medi natural en evolució i d'una societat també en evolució, és en si mateix, evolutiu. La qüestió que es planteja és, però, saber qui controla aquesta evolució dels paisatges, per a qui evolucionen i en quines direccions ho fan. El Loira ofereix un exemple que il·lustra aquesta problemàtica. L'article ressalta les solidaritats geogràfiques existents entre el seu curs alt i el baix, les quals forcen a una perspectiva global en l'acondiciament del riu i planteja els conflictes creats entre els col·lectius que l'utilitzen en el seu recorregut final, entre Angers i Nantes.El paisaje, confrontación de un medio natural en evolución y una sociedad también en evolución, es en si mismo, evolutivo. La cuestión que se plantea es saber quién controla esta solución de los paisajes, para quien evolucionan y en qué dirección lo hacen. El Loira ofrece un ejemplo que ilustra esta problemática. El articulo resalta las solidaridades geográficas que existen entre el curso alto y bajo del río, las cuales imponen una perspectiva global a la hora de emprender intervenciones de acondicionamiento y plantea los conflictos originados entre los colectivos que se disputan la utilización del río en su recorrido final, entre Angers y Nantes.Le paysage, confrontation d'un milieu naturel en évolution et d'une société, elle aussi en évolution, est en lui même évolutif. La question qui se pose est de savoir qui controle cette évolution des payasages, pour qui ils se transforment et en quelles directions. La Loire offre un exemple qui illustre bien ce problème. L'article souligne les solidarités géographiques qui existent entre le cours haut et bas du fleuve. Cela nous oblige i donner une perspective globale de l'aconditionnement du fleuve, des interventions et des conflits entre les collectifs qui se disputent l'utilisation du cours d'eau dans son trajet final, entre Angers et Nantes

    ‘Pole Test’ Measurements in Critical Leg Ischaemia

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    AbstractBackgroundFor the quantification of critical limb ischaemia (CLI) most vascular surgery units use sphygmo-manometric and transcutaneous oxygen pressure (TcPO2) measurements. However, measurements obtained by cuff-manometry can be overestimated especially in diabetic patients because of medial calcification that makes leg arteries less compressible. TcPO2 measurements present a considerable overlap in the values obtained for patients with different degrees of ischaemia and its reproducibility has been questioned. Arterial wall stiffness has less influence on the pole test, based on hydrostatic pressure derived by leg elevation, and this test seems to provide a reliable index of CLI.ObjectiveThe objective of this study was to evaluate the pole pressure test for detection of critical lower limb ischaemia, correlating results with cuff-manometry and transcutaneous oxygen pressure.DesignUniversity hospital-prospective study.Materials and methodsSeventy-four patients (83 legs) with rest pain or gangrene were evaluated by four methods: pole test, cuff-manometry, TcPO2 and arteriography. CLI was present if the following criteria were met: (a) important arteriographic lesions+rest pain with an ankle systolic pressure (ASP) ≤40mmHg and/or a TcPO2 ≤30mmHg, or (b) important arteriographic lesions+tissue loss with an ASP ≤60mmHg and/or a TcPO2 ≤40mmHg. Fifty-seven lower limbs met the criteria for CLI.ResultsMeasurements obtained by cuff-manometry were significantly higher to those obtained by pole test (mean pressure difference: 40mmHg, p<0.001). The difference between the two methods remained statistically significant for both diabetics (50.73, p<0.001) and non-diabetics (31.46, p<0.001). Mean TcPO2 value was 15.51mmHg and there was no important difference between patients with and without diabetes. Overall, there was a correlation between sphygmomanometry and pole test (r=0.481). The correlation persisted for patients without diabetes (r=0.581), but was not evident in patients with diabetes. Correlation between pole test and TcPO2 was observed only for patients with diabetes (r=0.444). There was no correlation between cuff-manometry and TcPO2. The pole test offered an accuracy of 88% for the detection of CLI. The sensitivity of this test was 95% and the specificity 73%

    Multi-Stability and Pattern-Selection in Oscillatory Networks with Fast Inhibition and Electrical Synapses

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    A model or hybrid network consisting of oscillatory cells interconnected by inhibitory and electrical synapses may express different stable activity patterns without any change of network topology or parameters, and switching between the patterns can be induced by specific transient signals. However, little is known of properties of such signals. In the present study, we employ numerical simulations of neural networks of different size composed of relaxation oscillators, to investigate switching between in-phase (IP) and anti-phase (AP) activity patterns. We show that the time windows of susceptibility to switching between the patterns are similar in 2-, 4- and 6-cell fully-connected networks. Moreover, in a network (N = 4, 6) expressing a given AP pattern, a stimulus with a given profile consisting of depolarizing and hyperpolarizing signals sent to different subpopulations of cells can evoke switching to another AP pattern. Interestingly, the resulting pattern encodes the profile of the switching stimulus. These results can be extended to different network architectures. Indeed, relaxation oscillators are not only models of cellular pacemakers, bursting or spiking, but are also analogous to firing-rate models of neural activity. We show that rules of switching similar to those found for relaxation oscillators apply to oscillating circuits of excitatory cells interconnected by electrical synapses and cross-inhibition. Our results suggest that incoming information, arriving in a proper time window, may be stored in an oscillatory network in the form of a specific spatio-temporal activity pattern which is expressed until new pertinent information arrives

    Histoire immédiate ou actualité : la perception des guerres du monde contemporain quand l’école « n’en parle pas »

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    L’exploitation de 442 questionnaires remplis par des élèves de 9 à 13 ans en République tchèque, Roumanie, Royaume-Uni, USA, France permet d’approcher l’émergence des représentations enfantines de la guerre, à travers les images et les éléments de compréhension rencontrés dans les media (presse, télévision et de plus en plus Internet). Les jeux vidéo, souvent facilement accessibles mettent aussi en scène ces conflits et il est difficile de savoir s’ils influencent le graphisme des enfants.This paper is based on 442 questionaires filled by pupils aged 9 to 13 from the Czech Republic, Romania, the UK, the USA and France. Answers and drawings enable us to form an idea of pupils' mental representations of war from the pictures and explanations they find in media : papers, television and the net. Videogames also represent these armed conflicts and it is hard to know if they have any influence on pupils' style of drawing

    Mortality and Morbidity Following Endovascular Repair of Abdominal Aortic Aneurysms: Analysis of Two Single Centre Experiences

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    AbstractObjective to show how differences in anatomical and physiological risk factors can affect the outcome of endovascular repair of AAA by describing the experience of two centres with different selection policies. Methods one hundred and thirty-five patients (group I) were treated at Queen's Medical Centre (Nottingham, U.K.) using 101 in-house made and 34 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 26 mm, 27 mm, 40°, respectively. Seventy-six patients had ischaemic heart disease, 47 had left ventricular failure, median forced expiratory volume in one second (FEV1) was 83%, median creatinine was 100 μmol/l and median age was 72 years. Fifty patients (group II) were treated at Timone Hospital (Marseilles, France) using seven in-house made and 43 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 25 mm, 34 mm, 33°, respectively. Thirteen patients had ischaemic heart disease, two had left ventricular failure, median forced expiratory volume in one second was 101%, median creatinine was 108 μmol/l and mean age was 72 years. Results anatomical characteristics of the proximal neck were significantly worse in group I (p=0.02 for the three variables). Cardiac comorbidities were more frequent and mean FEV1 was lower in group I (p<0.0001 and p=0.001, respectively. Median aneurysm diameter was significantly greater in group I (65 mm) than in group II (53 mm) (p<0.001). Postoperative mortality was 9% and 0% in groups I and II respectively (p=0.03). The incidence of technical complications (groin wound complications and side branches endoleaks being excluded) was 20% and 0% in groups I and II, respectively (p=0.0006). Conclusion postoperative mortality and technical complication rates were significantly greater in group I than in group II, readily explained by poorer general condition and worse anatomical characteristics of the proximal neck in group I

    Maturation of the GABAergic Transmission in Normal and Pathologic Motoneurons

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    γ-aminobutyric acid (GABA) acting on Cl−-permeable ionotropic type A (GABAA) receptors (GABAAR) is the major inhibitory neurotransmitter in the adult central nervous system of vertebrates. In immature brain structures, GABA exerts depolarizing effects mostly contributing to the expression of spontaneous activities that are instructive for the construction of neural networks but GABA also acts as a potent trophic factor. In the present paper, we concentrate on brainstem and spinal motoneurons that are largely targeted by GABAergic interneurons, and we bring together data on the switch from excitatory to inhibitory effects of GABA, on the maturation of the GABAergic system and GABAAR subunits. We finally discuss the role of GABA and its GABAAR in immature hypoglossal motoneurons of the spastic (SPA) mouse, a model of human hyperekplexic syndrome

    La production scientifique issue de la formation initiale à la faculté de médecine d’Angers entre 2002 et 2008 : de bonne qualité mais insuffisante

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    IntroductionL’activité de publication scientifique issue de la formation initiale est mal connue. Nous avons évalué la proportion des thèses et des mémoires de spécialité aboutissant à une publication, leur impact en termes de points SIGAPS et les principaux obstacles à la publication de ces travaux. Méthodes Les thèses de doctorat en médecine soutenues de 2002 à 2008 à la faculté de médecine d’Angers ont été recensées à partir du système universitaire de documentation (SUDOC), et les mémoires de spécialité directement auprès des diplômés. Les publications ont été recherchées dans Medline via Pubmed, ISI Web of Knowledge et dans les trois rapports SIGAPS de 2002 à 2008. Une enquête cherchant à connaître les obstacles à la publication a été lancée auprès de tous les directeurs de thèses et responsables de discipline impliqués. Résultats Cinq cent quatre-vingt-dix-huit thèses ont été soutenues, 311 (52 %) en médecine générale et 287 (48 %) en spécialités. Cent soixante-cinq thèses ont donné lieu à publication (28 %) dont 97 (16 %) indexés dans Medline via Pubmed (soit 11 % en médecine générale et 22 % en spécialité). Trente-trois de ces 97 articles (35 %) ont été publiés dans des journaux de haute qualité classés A, B ou C de la classification SIGAPS. Ces articles issus des thèses ont représenté 4,17 % du score SIGAPS du CHU calculé sur un total de 2088 articles au cours de cette période. Deux cent quatre mémoires de spécialités ont donné lieu à 69 articles (33,8 %), dont 50 (24,5 %) indexés dans Medline. Les taux de publication des mémoires de DES et de DESC ont été respectivement de 31 % (45/145) et de 40,7 % (24/59). Ils ont représenté 1,9 % (432 points) du score total SIGAPS. Les principaux obstacles ressentis pour la publication ont été le manque de temps des directeurs, l’éloignement des étudiants après la soutenance et le manque de moyens logistiques. Conclusion La production scientifique issue de la formation initiale à la faculté de médecine d’Angers a été de bonne qualité mais insuffisante quantitativement et peu contributive au financement du CHU malgré un nombre important de diplômés. Un soutien logistique mérite d’être envisagé afin de valoriser la production scientifique issue de la formation initiale
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