514 research outputs found

    Cyrille Aillet, Patrice Cressier, Sophie Gilotte (Ă©d.), Sedrata. Histoire et archĂ©ologie d’un carrefour du Sahara mĂ©diĂ©val Ă  la lumiĂšre des archives inĂ©dites de Marguerite van Berchem

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    L’ouvrage que consacrent Cyrille Aillet, Patrice Cressier et Sophie Gilotte Ă  la ville saharienne de Sedrata, la « PompĂ©i des sables », est une magnifique illustration de la fĂ©conditĂ© des dialogues : dialogue entre historiens et archĂ©ologues, dialogue Ă©galement entre ces chercheurs actuels et la « Dame de Sedrata », l’archĂ©ologue suisse Marguerite van Berchem (1892-1984) qui fouilla le site entre 1950 et 1954, laissant une importante documentation en partie inĂ©dite. Quand les terrains de foui..

    La fitna andalouse du xie siĂšcle

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    Dans l’historiographie d’al-Andalus, le dĂ©but du xie siĂšcle est le temps de la fitna, celui de la guerre civile qui provoque l’effondrement du califat omeyyade de Cordoue. Perçue comme une rupture majeure, elle serait ce moment tĂ©nu oĂč les Ă©quilibres s’inversent, oĂč l’Espagne musulmane, dĂ©sormais divisĂ©e et amoindrie, commence Ă  reculer devant les dĂ©buts de la Reconquista chrĂ©tienne. Les contemporains comme les historiens ont portĂ© un jugement extrĂȘmement nĂ©gatif sur cette pĂ©riode qui va de 1009 Ă  1031 et que prolonge le temps des TaĂŻfas, les royaumes nĂ©s de la partition, ces enfants naturels de la fitna dont l’histoire occupe tout le reste du xie siĂšcle. Il semblerait cependant que la rupture soit Ă  relativiser  : en amont de la fitna, alors que domine le puissant hadjĂźb al-MansĂ»r, les germes de la discorde sont dĂ©jĂ  solidement plantĂ©s. En aval enfin, les brillants traits du reste du siĂšcle ne plaident pas en faveur d’un commencement de la fin. Cette Ă©poque de division et de conflit est certainement l’un des ces moments essentiels oĂč quelque chose de l’identitĂ© andalouse s’est jouĂ©, avant que la PĂ©ninsule ne soit sous la domination des BerbĂšres almoravides.In the historiography of al-Andalus, the early eleventh century is the time of the fitna, the time of the civil war which provoked the collapse of the Umayyad caliphate of Cordoba. Seen as a major breakup, it might be that tenuous moment when the balance is upset, when Muslim Spain, henceforth divided and weakened, begins to lose ground against the beginnings of the Christian Reconquista. The people of that period as well as the historians have formed an extremely negative judgment on this period which goes from 1009 to 1031 and is followed by the time of the TaĂŻfas, the kingdoms grown from this division, heirs to the fitna which takes up the rest of the eleventh century. It seems, nonetheless, that this breakup should be moderated  : prior to the fitna, at the time when hadjĂźb al-MansĂ»r ruled, the seeds of strife had already been deeply sown. Finally, posterior to it, the brilliant aspects of the rest of the century do not speak for the beginning of the end. This time of division and strife is no doubt one of these essential moments when a part of the Andalusian identity was shaped, before the Peninsula got ruled by the Almoravid Berbers

    1 H-MR-spektroskopische Bestimmung der zerebralen Glutamat- und Glutaminkonzentration bei Patienten mit einer Demenz vom Alzheimer-Typ

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    Die in vivo MR-Protonenspektroskopie (1H-MRS) ist ein nichtinvasives Verfahren, das die Untersuchung biochemischer Substanzen beim Lebenden ermöglicht. In einer prospektiven Studie wurden Patienten, die an einer Demenz vom Alzheimer-Typ (DAT) litten, und altersentsprechende Probanden mit der 1H-MRS untersucht. Im Hirngewebe wurden Konzentrationen von MolekĂŒlen bestimmt, die Aussagen ĂŒber die zellulĂ€re Zusammensetzung ermöglichen. Das Hauptinteresse galt der Untersuchung von Glutamat und Glutamin, da ein Überangebot des Neurotransmitters Glutamat im synaptischen Spalt möglicherweise fĂŒr die Neurodegeneration beim M. Alzheimer mitverantwortlich ist. Bei 29 Patienten mit einer DAT sowie 19 Probanden wurden zwei Volumina in Kortex und Marklager des Parietallappens bei 1,5 Tesla MagnetfeldstĂ€rke mit einer PRESS-Sequenz (TE = 22 ms, TR = 3 s) untersucht. Die Patienten waren kognitiv leicht bis mittelschwer beeintrĂ€chtigt (Mini Mental State Examination, MMSE, 11-27 Punkte). Die quantitative Auswertung der Spektren erfolgte nach der "phantom replacement method" mit dem Softwareprogramm LCModel. Als Kriterium fĂŒr die ZuverlĂ€ssigkeit der Konzentrationsangaben diente die vom Programm als %SD-Wert angegebene Auswertegenauigkeit der Einzelmessungen. Neben dem Glutamat- und Glutamingehalt wurden der Liquorgehalt im kortikalen Messvolumen und die Konzentrationen der MolekĂŒle N-Acetyl-Aspartat und N-Acetyl-Aspartyl- Glutamat (tNAA), myo-Inositol (mI), Kreatin und Kreatinphosphat (tCr) sowie der cholinhaltigen Substanzen (tCh) bestimmt. Bei den Patienten konnten 25 aussagekrĂ€ftige Spektren aus der Rindenregion und 19 aus dem Marklager des Parietallappens gemessen werden, bei den Probanden 17 Kortex- und 13 Marklager-Spektren. Glutamat und Glutamin können mit der in vivo-Spektroskopie wegen ihrer sich ĂŒberlappenden Resonanzen nicht separat bestimmt werden und wurden deshalb als „Glx“ zusammengefasst. Der Glx-Gehalt betrug in der Rindenregion bei den Patienten im Durchschnitt 15,48 ± 5,15 mmol/l, bei den Probanden 13,98 ± 3,14 mmol/l. Die um 11% höhere Konzentration bei den Patienten war nicht signifikant. Die Glx-Konzentrationen im Marklager betrugen 8,16 ± 3,79 mmol/l bei den Patienten und 8,14 ± 3,71 mmol/l bei den Probanden. Nach dem Kriterium der %SD war die ZuverlĂ€ssigkeit der Konzentrationsbestimmung von Glutamat und Glutamin eingeschrĂ€nkt, was auf die protonenspektroskopischen Eigenschaften von Glutamat und Glutamin zurĂŒckzufĂŒhren ist. Sie erzeugen wegen ihrer gekoppelten Resonanzen breite und mehrgipflige Protonensignale, die wegen der resultierenden niedrigen Signalamplitude fĂŒr LCModel von MakromolekĂŒlresonanzen oder von Artefakten, die durch ungenĂŒgende WasserunterdrĂŒckung entstehen, schwierig abzugrenzen sind. Die %SD-Werte der Einzelmessungen von tNAA, mI, tCr und tCh waren gering, die Messergebnisse können daher als zuverlĂ€ssig angesehen werden. Die tNAA-Konzentrationen in beiden Gruppen unterschieden sich weder in der grauen noch in der weißen Substanz signifikant voneinander. Im Hirnrindenvolumen zeigte sich bei den Patienten jedoch eine positive Korrelation von tNAA und MMSE-Ergebnis, also eine Reduktion von tNAA mit zunehmenden kognitiven Einbußen. Dies spricht fĂŒr eine Abnahme des neuronalen Volumenanteils mit fortschreitender Erkrankung. Der durchschnittliche myo-Inositolgehalt im Marklagervolumen lag in der Patientengruppe um 20% höher als bei den Probanden. Der Unterschied erreichte jedoch kein Signifikanzniveau (p = 0,09). Im Rindenvolumen war die mittlere myo-Inositolkonzentration bei den Patienten um 7% höher als in der Kontrollgruppe, auch hier war der Unterschied nicht signifikant. Der nichtsignifikante myo-Inositolanstieg lĂ€sst sich als mĂ€ĂŸige entzĂŒndliche oder reaktive Gliaproliferation interpretieren. Die tCr-Konzentrationen in beiden Gruppen unterschieden sich nicht, jedoch bestand bei den DAT-Patienten eine positive Korrelation des tCr-Gehalts mit der MMSE-Punktzahl in der grauen Substanz des Parietallappens, die Konzentration nahm also mit zunehmendem Schweregrad der Demenz ab. Bei der durchschnittlichen tCh-Konzentration bestanden keine Gruppenunterschiede in den untersuchten Regionen. Die Patienten wiesen eine signifikante Zunahme des mittleren Liquoranteils um 16% im kortikalen Volumen auf. Dies ist als kortikale Hirngewebeatrophie in frĂŒhen und mittleren Stadien der DAT zu werten. WĂ€hrend die in vivo-Konzentrationen von tNAA, mI, tCr und tCh zuverlĂ€ssig bestimmt werden konnten, war die Messung von Glutamat und Glutamin bei 1,5 T mit technischen Schwierigkeiten verbunden. Wegen der hohen Standardabweichungen konnte aus dieser Untersuchung keine gesicherte Aussage zu einer möglichen KonzentrationsĂ€nderung dieser AminosĂ€uren bei der DAT abgeleitet werden. Es ist zu erwarten, dass hier durch MR-GerĂ€te mit 3 T FeldstĂ€rke sowie durch den Einsatz der parallelen Bildgebung ein erheblich höheres Signal/Rausch-VerhĂ€ltnis und damit genauere Ergebnisse erzielt werden können.Proton magnetic resonance spectroscopy (1H-MRS) is a noninvasive tool for the examination of neurochemistry in vivo. The aim of the present prospective study is the investigation of in vivo-detectable changes in metabolite concentrations during early stages of probable AlzheimerÂŽs disease (AD) using 1H-MRS. To obtain information about tissue composition the concentrations of several metabolites were estimated. The main focus of this study were the amino acids glutamate and glutamine, since an excessive supply of the neurotransmitter glutamate in the synaptic cleft is considered to be a possible cause for neurodegeneration in AD. For 29 patients with probable AD and for 19 elderly controls two volumes in parietal grey and white matter were examined at 1.5 Tesla using a single-voxel short echo PRESS sequence (TE = 22 ms, TR = 3 s). The patients had mild to moderate dementia (mini mental state examination, MMSE, 11-27). Their spectroscopic findings were compared to the data obtained from 19 healthy elderly controls. Metabolite concentrations were quantified using the software tool LCModel (Provencher 1993). For each data set the compliance with accuracy criteria was based on the %SD values. These values are calculated by the software measuring the reliability of the obtained metabolite concentrations. In patients, 25 spectra with sufficient quality were obtained from parietal grey matter (PGM) and 19 from white matter (PWM) and compared to 17 PGM spectra and 13 PWM spectra from controls. For volumes in parietal grey matter, the fraction of cerebrospinal fluid was estimated. Absolute concentrations of glutamate and glutamine (Glx), N-acetyl aspartate and N-acetyl aspartyl glutamate (tNAA), myo-Inositol (mI), creatine and phosphocreatine (tCr) and choline-containing compounds (tCh) were calculated based on the phantom replacement method. Due to overlapping proton resonances, glutamine and glutamate cannot be separated in vivo and therefore are summed up as “Glx”. In patients, mean Glx concentration in PGM was 15,48 ± 5,15 mmol/l, in healthy controls 13,98 ± 3,14 mmol/l. The 11% increase in patients did not reach significance. In PWM, Glx concentration in probable AD patients was 8,16 ± 3,79 mmol/l, in controls 8,14 ± 3,71 mmol/l. These values had high %SD values compared to the singulett signals (tNAA, mI, tCho, tCr) since glutamate and glutamine are broadened due to the complex multiplett structures. The respective low amplitudes are sometimes difficult to discriminate from baseline modulations caused by imperfect water suppression or macromolecules, resulting in a reduced accuracy of the LCModel fit. The estimates of tNAA, mI, tCr and tCh had low %SD, indicating high accuracy of the calculated quantitative concentrations. There were no significant alterations of tNAA concentrations in either parietal grey or white matter, but in patients, tNAA showed a significant positive correlation with MMSE score in PGM. Since tNAA is considered to be a neuronal marker, this correlation may indicate a reduction in neuronal volume as the disease proceeds. Myo-inositol concentrations in patients were 20% elevated for PWM in probable AD patients compared to controls, but the difference did not reach significance (p = 0,09). In PGM, patients showed a 7% increase in mI, which was not significant either. The moderate increase in myo-Inositol in PWM for patients can be interpreted as mild gliosis, e.g. due to inflammation. There were no significant between-group differences in tCr concentrations in either of the volumina, but in patients, tCr correlated positively with MMSE score in PGM. tCh concentrations were similar in both regions in patients and controls. For probable AD patients, the fraction of cerebrospinal fluid in the parietal cortical volume was significantly increased by 16% compared to controls. This increase is in accordance with cortical atrophy in early and advanced stages of probable AD. NAA, mI, tCr and tCh concentrations were estimated with high accuracy, whereas the quantification of glutamate and glutamine at 1.5 T was difficult, mainly for technical reasons. Thus, the presented data do not provide sound information regarding potential changes of Glx concentrations in probable AD. Further improvement of in vivo Glx examination should be achieved by an improvement of signal-to-noise ratio at higher magnetic fields, e.g. 3 T MR scanners, and the use of parallel imaging

    La fitna : le dĂ©sordre politique dans l’Islam mĂ©diĂ©val

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    Pour la plupart des historiens français, hĂ©ritiers des rĂ©volutions, le dĂ©sordre est crĂ©ateur de sens, annonciateur d’un ordre nouveau. Il n’en est pas de mĂȘme dans l’Islam traditionnel : les chroniqueurs mĂ©diĂ©vaux tout comme les juristes ou les thĂ©ologiens ne tiennent pour dignes d’histoire que les rĂšgnes glorieux et les sectes victorieuses. Ils rejettent le dĂ©sordre, la fitna en arabe, dans le non-sens et se refusent mĂȘme Ă  l’expliquer de peur de le justifier. Selon un cĂ©lĂšbre hadith, « mieu..

    Management, risk factors and outcome of cranial dural arteriovenous fistulae: a single-center experience

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    Background: The role of endovascular interventions in managing dural arteriovenous fistulas (DAVFs) is increasing. Furthermore, in patients with aggressive DAVFs, different surgical interventions are required for complete obliteration or disconnection. Our objective was to evaluate the management of patients with intracranial DAVFs treated in our institution to identify the parameters that may help guide the long-term management of these lesions. Methods: The hospital records of 53 patients with intracranial DAVFs were reviewed. We then conducted a systematic telephone interview to obtain long-term follow-up information. Results: The main presenting symptoms were tinnitus and headache. Nineteen (35%) patients presented with intracranial bleeding, 84% of patients scored between 0 and 2 using a modified Rankin Scale at the last follow-up visit. Twenty-four patients were treated surgically. Overall postoperative complications occurred in seven (29%) surgically treated patients, but only two patients permanently worsened. For patients with Borden type II and III fistulas, the annual incidence of hemorrhage was 30%. Two patients had late recurrences of surgically and endovascularly occluded DAVFs. Long-term follow-up showed that compared with spinal DAVFs, only 50% of intracranial DAVFs showed complete remission of symptoms, 41% partial remission, 6% no remission and 4% deterioration of symptoms that led to treatment of the DAVF. Conclusion: In general, intracranial DAVFs can be successfully surgically managed by simple venous disconnection in many cases. However, half of the patients do not show complete remission of symptoms. Age and the occurrence of perioperative complication were the most important determinants of outcom

    La libĂ©ralisation des chemins de fer europĂ©ens au regard de l’histoire

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    La table ronde « La libĂ©ralisation des chemins de fer europĂ©ens au regard de l’histoire : avancĂ©e, risque ou rĂ©gression ? » avait pour mission de mettre en perspective historique la libĂ©ralisation des chemins de fer europĂ©ens : son Ă©volution et sa place dans une histoire Ă  long terme, ses rĂ©sultats, les nouvelles relations que ces mesures ont instituĂ©es entre gestionnaires des rĂ©seaux et exploitants de transport, entre le secteur des transports et les pouvoirs nationaux, rĂ©gionaux ou locaux. AprĂšs une introduction historique assurĂ©e par MichĂšle Merger, chargĂ©e de recherche au CNRS, qui rappelle la directive 91/440 et ses quatre recommandations – sĂ©paration juridique et comptable de l’infrastructure des rĂ©seaux et de leur exploitation, indĂ©pendance de gestion des entreprises ferroviaires, leur assainissement financier et le libre accĂšs de nouvelles entreprises exploitantes Ă  l’infrastructure –, qui ont conduit Ă  une Ă©volution trĂšs rapide du secteur en quinze ans, quatre questions sont posĂ©es aux participants : quels sont les pays et les acteurs europĂ©ens les plus rĂ©fractaires et les plus favorables Ă  cette Ă©volution, et quels sont leurs arguments respectifs ? Existe-t-il une typologie des rĂ©formes entreprises, conduisant Ă  des modĂšles plus u moins largement diffusĂ©s ? Quel type de service ferroviaire attendons-nous et pouvons-nous attendre de cette rĂ©forme, en d’autres termes, quel est le devenir du concept de service public ferroviaire ? Qu’en est-il de la revitalisation du fret ferroviaire au lendemain de l’ouverture des corridors de fret favorisĂ©s par ces directives, quelle est la nouvelle Europe du fret ferroviaire ? Patrice Leroy, directeur honoraire de la SNCF, ancien secrĂ©taire gĂ©nĂ©ral adjoint du CEEP, prĂ©sident dĂ©lĂ©guĂ© de l’AHICF anime ensuite le dĂ©bat qui rĂ©unit Yves Crozet, professeur Ă  l’universitĂ© LumiĂšre-Lyon 2, Michel LebƓuf, directeur DĂ©veloppement Ă  Voyageurs France Europe, SNCF, Hubert du Mesnil, prĂ©sident de RFF et Émile Quinet, professeur Ă©mĂ©rite Ă  l’École nationale des Ponts et ChaussĂ©es.ROUND TABLE with Yves CROZET, Michel LEBƒUF, Patrice LEROY, MichĂšle MERGER, Hubert du MESNIL and Emile QUINET The purpose of the round table discussion of “The liberalization of European railways from a historical perspective: progress, risk, or regression?” was to put the liberalization of European railways into a historical perspective: the discussants’ goal was to define the place and evolution of this trend in an open-ended history, its results, and the new relationships that such measures have brought about between network managers and transportation operators, as well as between the transportation sector and national, regional, and local authorities. After an historical introduction provided by MichĂšle Merger, a researcher at the CNRS, who reminded us of the 91/440 directive and its four recommendations—the legal and accounting separation of network infrastructures and their operations, the independent management of the railway companies and their financial streamlining, and open access to the infrastructure for new operating companies—led to a very rapid evolution of the sector in fifteen years, the participants were asked four questions: which European countries and players are the most opposed to and the most in favor of this evolution, and what are their respective arguments? Is there a typology of business reform that leads to more or less widespread models? What kind of railway service is in store for us and what should we expect from such reforms? In other words, what is the future of the concept of public railway service? What will be the impact of the revitalization of rail freight in the aftermath of the opening of freight corridors advantaged by these directives? What will the new Europe of rail freight look like? Patrice Leroy, honorary director of the SNCF, former adjunct secretary general of the CEEP, and Deputy Chairman of the AHICF, then moderated the debate that brought together Yves Crozet, professor at the university LumiĂšre-Lyon 2, Michel Leboeuf, developmental director of Voyageurs France Europe, SNCF, Hubert du Mesnil, President of the RFF, and Emile Quinet, professor emeritus at the Ecole nationale des Ponts et ChaussĂ©es

    Limb-shaking transient ischemic attacks: case report and review of literature

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    BACKGROUND: Limb shaking Transient Ischemic Attack is a rare manifestation of carotid-occlusive disease. The symptoms usually point towards a seizure like activity and misdiagnosed as focal seizures. On careful history the rhythmic seizure like activity reveals no Jacksonian march mainly precipitated by maneuvers which lead to carotid compression. We here present a case of an elderly gentleman who was initially worked up as suffering from epileptic discharge and then later on found to have carotid occlusion. CASE PRESENTATION: Elderly gentleman presented with symptoms of rhythmic jerky movements of the left arm and both the lower limbs. Clinical suspicion of focal epilepsy was made and EEG, MRI-Brain with MRA were done. EEG and MRI-Brain revealed normal findings but the MRA revealed complete occlusion of right internal carotid artery. On a follow-up visit jerky movements of the left arm were precipitated by hyperextension and a tremor of 3–4 Hz was revealed. Based on this the diagnosis of low flow TIA was made the patient was treated conservatively with adjustment of his anti-hypertensive and anti-platelet medications. CONCLUSION: Diagnosis of limb-shaking TIA is important and should be differentiated from other disorders presenting as tremors. Timely diagnosis is important as these patients are shown to benefit from reperfusion procedures either surgical or radiological reducing their risk of stroke
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