Le collège et l’académie de Saumur, un même établissement ?

Entre les lettres patentes de mars 1593 par lesquelles Henri IV accorde à Philippe Duplessis-Mornay l’autorisation de « faire construire, ériger et bâtir un collège » à Saumur et, en 1613, la tenue d’un registre « des affaires de l’académie », vingt années s’écoulent au cours desquelles le gouverneur de Saumur se bat pour l’ouverture d’un collège de plein exercice et, à partir de 1606, d’une académie pour la formation théologique des pasteurs. C’est donc un établissement composé de deux corps distincts, celui du collège et de ses régents avec un principal à sa tête, celui de l’académie et de ses professeurs dirigés par un recteur, qui fonctionne du début du XVIIe siècle jusqu’à l’arrêt du conseil du 8 janvier 1685 « portant extinction et suppression du collège et Académie » . À Saumur, on peut distinguer quatre principales institutions réformées qui interviennent dans le domaine éducatif : le collège de plein exercice, l’académie en tant que telle donnant une formation théologique, le consistoire, mais aussi jusqu’au début des années 1620 le gouverneur qui est omniprésent dans le fonctionnement de l’institution scolaire. Mais synodes nationaux et synodes provinciaux jouent également un rôle dans le système scolaire . Malgré cette distinction collège d’une part, académie d’autre part, les deux corps sont étroitement liés, autant sur un plan institutionnel que dans la vie quotidienne. Ce sont ces relations étroites que nous proposons d’étudier en s’appuyant principalement sur trois sources essentielles : les registres de l’académie qui couvrent les années 1613-1673, puis les années 1683-1684 , le livre des recettes de l’académie pour les années 1631-1685 , les actes des synodes provinciaux d’Anjou-Touraine-Maine qui ont été retrouvés, soit de 1594 pour les plus anciens à 1683, année du dernier synode tenu par la province . Quelle valeur peut-on attribuer à cette distinction collège-académie ? Peut-on considérer que l’institution traite différemment les deux corps ? Au sein des deux corps, cette distinction est-elle ressentie et faite ? Ces différentes questions peuvent être abordées à partir du cadre institutionnel existant, puis de la volonté de mettre en avant ces deux corps, et enfin de voir quels sont les autres éléments d’opposition entre collège et académie.

A shell-model calculation in terms of correlated subsystems

A method for solving the shell-model equations in terms of a basis which includes correlated subsystems is presented. It is shown that the method allows drastic truncations of the basis to be made. The corresponding calculations are easy to perform and can be carried out rapidly

Idiopathic orthostatic hypotension: Recent data (eleven cases) and review of the literature

Eight cases of Shy-Drager syndrome and three of Bradbury-Eggleston idiopathic orthostatic hypotension were examined. In all cases, examination of circulatory reflexes showed major dysfunction of the sympathetic vasoconstrictor system. Anomalies in the vagal cardiomoderator system were less constant. Normal urinary elimination of catecholamines was recorded daily. Characteristically, no elevation of blood or urine norepinephrine levels were found in orthostatism. Insulin hypoglycemia normally raised urinary adrenalin elimination in three of ten patients. Plasma dopa-beta-hydroxylase activity was normal. Renin-angiotensin-aldosterone system showed variable activity at basal state but usually rose during orthostatism. On the average, very low homovanillic acid levels were found in cerebrospinal fluid before and after probenecid; hydroxyindolacetic acid was normal. Cerebral autoregulation had deteriorated in two of four cases. Physiopathologically the two clinical types are indistinguishable with or without central neurological signs

A Spectacular VHE Gamma-Ray Outburst from PKS 2155-304 in 2006

Since 2002 the VHE (>100 GeV) gamma-ray flux of the high-frequency peaked BL Lac PKS 2155-304 has been monitored with the High Energy Stereoscopic System (HESS). An extreme gamma-ray outburst was detected in the early hours of July 28, 2006 (MJD 53944). The average flux above 200 GeV observed during this outburst is ~7 times the flux observed from the Crab Nebula above the same threshold. Peak fluxes are measured with one-minute time scale resolution at more than twice this average value. Variability is seen up to ~600 s in the Fourier power spectrum, and well-resolved bursts varying on time scales of ~200 seconds are observed. There are no strong indications for spectral variability within the data. Assuming the emission region has a size comparable to the Schwarzschild radius of a ~10^9 solar mass black hole, Doppler factors greater than 100 are required to accommodate the observed variability time scales.Comment: 4 pages, 3 figures; To appear in the Proceedings of the 30th ICRC (Merida, Mexico

Osteoprotegerin regulates cancer cell migration through SDF-1/CXCR4 axis and promotes tumour development by increasing neovascularization

We previously reported that OPG is involved in ischemic tissue neovascularization through the secretion of SDF-1 by pretreated-OPG endothelial colony-forming cells (ECFCs). As the vascularization is one of the key factor influencing the tumour growth and cancer cell dissemination, we investigated whether OPG was able to modulate the invasion of human MNNG-HOS osteosarcoma and DU145 prostate cancer cell lines in vitro and in vivo. Cell motility was analysed in vitro by using Boyden chambers. Human GFP-labelled MMNG-HOS cells were inoculated in immunodeficient mice and the tumour nodules formed were then injected with OPG and/or FGF-2, AMD3100 or 0.9% NaCl (control group). Tumour growth was manually followed and angiogenesis was assessed by immunohistochemistry. In vitro, SDF-1 released by OPG-pretreated ECFCs markedly attracted both MNNG-HOS and DU145 cells and induced spontaneous migration of cancer cells. In vivo, tumour volumes were significantly increased in OPG-treated group compared to the control group and OPG potentiated the effect of FGF-2. Concomitantly, OPG alone or combined with FGF-2 increased the number of new vasculature compared to the control group. Interestingly AMD3100, an inhibitor of SDF-1, prevented the in vivo effects of OPG induced by SDF-1 This study provides experimental evidence that OPG promotes tumour development trough SDF-1/CXCR4 axis

Active Galactic Nuclei under the scrutiny of CTA

Active Galactic Nuclei (hereafter AGN) produce powerful outflows which offer excellent conditions for efficient particle acceleration in internal and external shocks, turbulence, and magnetic reconnection events. The jets as well as particle accelerating regions close to the supermassive black holes (hereafter SMBH) at the intersection of plasma inflows and outflows, can produce readily detectable very high energy gamma-ray emission. As of now, more than 45 AGN including 41 blazars and 4 radiogalaxies have been detected by the present ground-based gamma-ray telescopes, which represents more than one third of the cosmic sources detected so far in the VHE gamma-ray regime. The future Cherenkov Telescope Array (CTA) should boost the sample of AGN detected in the VHE range by about one order of magnitude, shedding new light on AGN population studies, and AGN classification and unification schemes. CTA will be a unique tool to scrutinize the extreme high-energy tail of accelerated particles in SMBH environments, to revisit the central engines and their associated relativistic jets, and to study the particle acceleration and emission mechanisms, particularly exploring the missing link between accretion physics, SMBH magnetospheres and jet formation. Monitoring of distant AGN will be an extremely rewarding observing program which will inform us about the inner workings and evolution of AGN. Furthermore these AGN are bright beacons of gamma-rays which will allow us to constrain the extragalactic infrared and optical backgrounds as well as the intergalactic magnetic field, and will enable tests of quantum gravity and other "exotic" phenomena.Comment: 28 pages, 23 figure

The VO: A Powerful Tool for Global Astronomy

Since its inception in the early 2000's, the Virtual Observatory (VO), developed as a collaboration of many national and international projects, has become a major factor in the discovery and dissemination of astronomical information worldwide. The International Virtual Observatory Alliance (IVOA) has been coordinating all these efforts worldwide to ensure a common VO framework that enables transparent access to and interoperability of astronomy resources (data and software) around the world. The VO is not a magic solution to all astronomy data management challenges but it does bring useful solutions in many areas borne out by the fact that VO interfaces are broadly found in astronomy's major data centres and projects worldwide. Astronomy data centres have been building VO services on top of their existing data services to increase interoperability with other VO-compliant data resources to take advantage of the continuous and increasing development of VO applications. VO applications have made multi-instrument and multi-wavelength science, a difficult and fruitful part of astronomy, somewhat easier. More recently, several major new astronomy projects have been directly adopting VO standards to build their data management infrastructure, giving birth to ‘VO built-in' archives. Embracing the VO framework from the beginning brings the double gain of not needing to reinvent the wheel and ensuring from the start interoperability with other astronomy VO resources. Some of the IVOA standards are also starting to be used by neighbour disciplines like planetary sciences. There is still quite a lot to be done on the VO, in particular tackling the upcoming big data challenge and how to find interoperable solutions to the new data analysis paradigm of bringing and running the software close to the data. We report on the current status and also desire to encourage others to adopt VO technology and engage them in the effort of developing the VO. Thus, we wish to ensure that the VO standards fit new astronomy projects requirements and needs