 <html> <head> <meta http-equiv="content-type" content="text/html;charset=iso-8859-1" /> <meta name="keywords" content="SPhT/Saclay Service de Physique Thorique" /> <meta http-equiv="content-language" content="fr"> <title> CEA/SPhT : Calendrier des prochains sminaires et cours </title> <basefont face="Arial,Helvetica"> </head> <body bgcolor="#fffff0"> <table border="0" cellpadding="0" cellspacing="0" width="640" align="center"> <tr><td>  <img height="55" width="640" src="/fr/_SPhT_55.jpg" border="0" usemap="#map1"><map name="map1"><area shape="rect" alt="CEA" coords="20,10,130,55" href="http://www.cea.fr/"><area shape="rect" alt="CEA/DSM" coords="345,5,420,40" href="http://www-dsm.cea.fr/"><area shape="rect" alt="CEA/DSM/SPhT" coords="430,10,550,55" href="/fr/index.shtml"></map>    <table border="0" cellpadding="0" cellspacing="0" width="640" align="center"> <tr> <td width="640" align="right"><a href="mailto:spht-adm@spht.saclay.cea.fr"><font size="2" face="Arial,Helvetica">spht-adm@spht.saclay.cea.fr</font></a></td></tr> </table> <table border="0" cellpadding="0" cellspacing="0" width="640" align="center"><tr><td align="left"> <font size="5" face="Arial,Helvetica"><b> Calendrier des prochains sminaires et cours </b></font></td><td align="right"> <font size="2" face="Arial,Helvetica"><a href="site.shtml"><b>Plan du site</b></a></font></td></tr></table> <hr width="640" size=5 noshade align="center">   <p> <font size="2" face="Arial,Helvetica"> Sauf mention explicite, les s&eacute;minaires et les cours du SPhT ont lieu &quot;Salle Claude ITZYKSON&quot;, b&acirc;timent 774, pi&egrave;ce 1A. </font><p> <table border="0" cellpadding="0" cellspacing="0" width="640"><tr><td> <!-- DEB COURS --> <table width="640" border="0" cellpadding="0" cellspacing="0"><tr><td><font size="2" face="Arial,Helvetica" color="navy"><b> Vendredi 23 mai 2003</b></font></td><td align="right" width="400"><hr size="5" noshade></td></tr></table> <ul><li><font size="2" face="Arial,Helvetica"><b><a href="/seminaires/COURS18.ps">  14h15</a> :  Cours de Physique Th&eacute;orique de Saclay</b></font>  <font size="2" face="Arial,Helvetica" color="red"> Organis&eacute; en collaboration avec l'Ecole Doctorale de Physique  de la r&eacute;gion parisienne </font>  <font size="3" face="Arial,Helvetica"> <br><b> Antonio MASIERO<!-- orateur --></b> (Univ. di Padova et SPhT, Saclay)<br> <font size="3" face="Arial, Helvetica"><i></i></font>  <font size="3" face="Arial,Helvetica"><i> <!-- COURS18_suj --> The Flavour and CP Problems as Windows for New Physics Beyond the Standard Model Cours IV </i></font> </font> </ul> <!-- FIN COURS --> <!-- DEB PSTAT --> <table width="640" border="0" cellpadding="0" cellspacing="0"><tr><td><font size="2" face="Arial,Helvetica" color="navy"><b> Lundi 26 mai 2003</b></font></td><td align="right" width="400"><hr size="5" noshade></td></tr></table> <ul><li><font size="2" face="Arial,Helvetica"><b><a href="/seminaires/PSTAT16.ps">  14h15</a> :  S&eacute;minaire de physique statistique</b></font>  <font size="3" face="Arial,Helvetica"> <br><b> Olivier GOLINELLI<!-- orateur --></b> (SPhT, CEA/Saclay)<br> <font size="3" face="Arial, Helvetica"><i></i></font>  <font size="3" face="Arial,Helvetica"><i> <!-- PSTAT16_suj --> Spectres d'arbres al&#233;atoires </i></font> </font> <font size="2" face="Arial,Helvetica"><p align="justify"> <!-- PSTAT16_res --> On prsentera une analyse de la densit spectrale des   matrices d'adjacence de grands arbres alatoires. Elle   prsente une infinit de pics delta pour tous les nombres   rels qui sont valeurs propres d'arbres fini. A ces pics sont   associs des vecteurs propres strictement localiss. Les   hauteurs de ces pics sont mesurs par des simulations   Monte-Carlo. Le reste de la densit spectrale est dcrit par   une fonction qui s'annule aux positions des pics; elle est   donc discontinue presque partout. </font> </ul> <!-- FIN PSTAT --> <!-- DEB PHYST --> <table width="640" border="0" cellpadding="0" cellspacing="0"><tr><td><font size="2" face="Arial,Helvetica" color="navy"><b> Mardi 27 mai 2003</b></font></td><td align="right" width="400"><hr size="5" noshade></td></tr></table> <ul><li><font size="2" face="Arial,Helvetica"><b><a href="/seminaires/PHYST24.ps">  11h00</a> :  S&eacute;minaire g&eacute;n&eacute;ral du SPhT</b></font>  <font size="3" face="Arial,Helvetica"> <br><b> Alain ARNEODO<!-- orateur --></b> (Laboratoire de Physique, Ecole Normale Sup&eacute;rieure de Lyon)<br> <font size="3" face="Arial, Helvetica"><i></i></font>  <font size="3" face="Arial,Helvetica"><i> <!-- PHYST24_suj --> From scale invariance to deterministic chaos in DNA sequences: a key to the understanding of the organization of gene location and orientation in the human genome? </i></font> </font> <font size="2" face="Arial,Helvetica"><p align="justify"> <!-- PHYST24_res --> Understanding how chromatin is spatially and dynamically   organized in the   nucleus of eucaryotic cells and how this affects genome   functions is   one of the main challenges of cell biology. Recent   technical progress   in live cell imaging have confirmed that the structure and   dynamics   of chromatin play an essential role in regulating many   biological   processes, such as gene activity, DNA replication,   recombination   and DNA damage repair. The emerging view is that genomes are   compartimentalized at the level of chromosome territories in   mammalian nuclei, into subchromosal structural domains that   are likely to be fundamental functional units that coordinate   the spatial organization and timing of replication and   transcription.   A remarkable property of these subchromosal foci is that they   are observed to correlate well to the replication foci   observed   in interphase nuclei, that are stable structures that persist   throughout the cell cycle and subsequent cell generations. As   regards to this probable clonal inheritance, one may wonder to   which extent one may learn about the higher order   structure and   dynamics of chromatin directly from the primary DNA sequence   and its functional landmarks. <br><P> In the first part of this talk, we use the continuous   wavelet transform   (WT) to characterize the scale invariance properties of   genomic   sequences. We show the existence of power-law correlations   over   distances up to , 20 - 30 kb as the signature of the   nucleosomal   structure of the 30 nm chromatin fiber. In a second part, we   explore the large-scale compositional heterogeneity of several   large (tens of megabases) contigs within human chromosomes   through   the optics of the WT microscope. We show that the GC   content displays   rather regular nonlinear oscillations with two main   frequencies   corresponding to 100 kb and 400 kb which are well   recognized characteristic   sizes of chromatin loops and loop domains involved in the   hierarchical folding of chromatin fibers. These frequencies   are also remarkably similar to the size of mammalian replicons   and replicon clusters. When further investigating   deviations from   intrastrand equimolarities between A and T and between G   and C,   we corroborate the existence of these two fundamental   frequencies   as the footprints of the replication and/or transcription   mutation   biais and we show that the observed nonlinear oscillations   enlighten   a remarkable cooperative organization of gene location and   orientation. When using classical techniques from   dynamical systems   theory, e.g. phase-portrait reconstruction, Poincar&#233;   section,   1-D map, we demonstrate that the observed nonlinear   oscillations   display all the characteristic features of chaotic strange   attractor   behavior of Shil'nikov type. As regards to current polymer   random   walk modelling of the random folding of chromosomal   fibers, our   results suggest as a very attractive alternative picture   that the   higher-order structure and dynamics of chromatin, in   relation with   replication and transcription processes, are governed by a   nonlinear   dynamical system that displays low-dimensional   deterministic chaos. </font> </ul> <!-- FIN PHYST --> <!-- DEB CORPU --> <table width="640" border="0" cellpadding="0" cellspacing="0"><tr><td><font size="2" face="Arial,Helvetica" color="navy"><b> Mercredi 28 mai 2003</b></font></td><td align="right" width="400"><hr size="5" noshade></td></tr></table> <ul><li><font size="2" face="Arial,Helvetica"><b><a href="/seminaires/CORPU20.ps">  14h15</a> :  S&eacute;minaire hadronique et des particules</b></font>  <font size="3" face="Arial,Helvetica"> <br><b><a href=mailto:wschebor@spht.saclay.cea.fr> Nicolas WSCHEBOR</a><!-- orateur --></b> (SPhT, CEA/Saclay)<br> <font size="3" face="Arial, Helvetica"><i></i></font>  <font size="3" face="Arial,Helvetica"><i> <!-- CORPU20_suj --> Le mod&#232;le de Gross-Neveu &#224; temp&#233;rature finie </i></font> </font> <font size="2" face="Arial,Helvetica"><p align="justify"> <!-- CORPU20_res --> Des r&#233;sultats nouveaux pour le mod&#232;le de Gross-Neveu &#224;   temp&#233;rature   finie seront pr&#233;sent&#233;s. Le mod&#232;le permet d'&#233;tudier   dans un contexte   simple la brisure spontan&#233;e de la sym&#233;trie chirale et   sa restauration   &#224; temp&#233;rature finie. Les r&#233;sultats obtenus incluent   les corrections   d'ordre 1/N au potentiel effectif pr&#233;sent&#233;es sous une forme   manifestement invariante sous le groupe de   renormalisation. On a   v&#233;rifi&#233;, en particulier, la compensation non-triviale de   divergences   ultraviolettes d&#233;pendantes de la temp&#233;rature. Il est   montr&#233; que les   fluctuations bosoniques, bien que formellement d'ordre 1/N   dominent le   comportement autour de la temp&#233;rature critique obtenue   &#224; l'ordre   dominant. Nous v&#233;rifions aussi que le comportement &#224;   haute temp&#233;rature   de la pression coincide avec celui obtenu en th&#233;orie de   perturbations avec   un couplage d&#233;fini &#224; une &#233;chelle d'ordre T. </font> </ul> <!-- FIN CORPU --> <!-- DEB PHYSM --> <table width="640" border="0" cellpadding="0" cellspacing="0"><tr><td><font size="2" face="Arial,Helvetica" color="navy"><b> Lundi 16 juin 2003</b></font></td><td align="right" width="400"><hr size="5" noshade></td></tr></table> <ul><li><font size="2" face="Arial,Helvetica"><b><a href="/seminaires/PHYSM17.ps">  11h00</a> :  S&eacute;minaire de physique math&eacute;matique</b></font>  <font size="3" face="Arial,Helvetica"> <br><b> Pierre MOUSSA<!-- orateur --></b> (SPhT, CEA/Saclay)<br> <font size="3" face="Arial, Helvetica"><i> &Eacute;changes d'intervalles, Surfaces de Riemann et Billards plans </i></font>  <font size="3" face="Arial,Helvetica"><i> <!-- PHYSM17_suj --> </i></font> </font> <font size="2" face="Arial,Helvetica"><p align="justify"> <!-- PHYSM17_res --> <!-- /tmp/resume_27813_4 -->  Les transformations d'&eacute;changes d'intervalles appara&icirc;ssent dans la description des r&eacute;flexions dans certains billiards plans. Elles sont alors naturellement associ&eacute;es &agrave; des surfaces de Riemann de genre positif ou nul. Le cas de deux intervalles est celui du tore (complexe), et on y rencontre des probl&egrave;mes de petits diviseurs lorsque on cherche &agrave; y int&eacute;grer un champ de vecteurs. La g&eacute;n&eacute;ralisation aux surfaces de Riemann de genre positif pr&eacute;sente des difficult&eacute;s analogues. On indiquera comment ont peut aborder ces probl&egrave;mes par le biais de l'&eacute;quation cohomologique pour les &eacute;changes d'intervalles, et on montrera comment s'y introduit un algorithme g&eacute;n&eacute;ralisant la fraction continue usuelle. </font> </ul> <!-- FIN PHYSM --> </td></tr></table> &nbsp;<table border="0" width="640" cellspacing="0" cellpadding="0" align="center"> <tr height="10"> <td valign="bottom" colspan="2" height="10"> <hr width="640" size="5" noshade align="center">  </td></tr> <tr> <td width="460"><font size="2" face="Arial,Helvetica"><b>CEA/DSM/SPhT - CNRS/SPM/URA 2306</b></font></td> <td valign="bottom"><font size="1" face="Arial,Helvetica">  Update: 22/05/2003<!-- jour --> 			</font></td> </tr> <tr> <td><font size="2" face="Arial,Helvetica"> Calendrier des prochains sminaires et cours 			</font></td> <td valign="bottom"><font size="1" face="Arial,Helvetica">  &copy; CEA 2000 <!-- # -- flastmod file="$DOCUMENT_NAME" --> - All rights reserved</font></td> 	</tr> </table> <table border="0" cellpadding="0" cellspacing="0" width="640" bgcolor="silver" align="center"> 	<tr height="16"><br> 		<td height="16">&nbsp;&nbsp;&nbsp;&nbsp;</td> <td width="640" height="16"> 			<center> <font size="2" face="Arial,Helvetica">[ <a href="/site.shtml">Site Map</a> | <a href="/index.shtml">Welcome</a> | <a href="/presentation.shtml">Presentation</a> | <a href="/sem_week.shtml">The Week in Brief</a> | <a href="/activities.shtml">Scientific Activities</a> | <a href="/jobs.shtml">Jobs</a> | <a href="/directory.shtml">Directory</a> | <a href="/access.shtml">Location and Access</a> ] </font></center> 		</td> 	</tr> </table> </font></td></tr></table></body></html>  
