1,224 research outputs found
Ordinary deformations are unobstructed in the cyclotomic limit
The deformation theory of ordinary representations of the absolute Galois
groups of totally real number fields (over a finite field ) has been studied
for a long time, starting with the work of Hida, Mazur and Tilouine, and
continued by Wiles and others. Hida has studied the behaviour of these
deformations when one considers the -cyclotomic tower of extensions of the
field. In the limit, one obtains a deformation ring classifying the ordinary
deformations of the (Galois group of) the -cyclotomic extension. We show
that if this ring in Noetherian (a natural assumption considered by Hida) it is
free over the ring of Witt vectors of . This however imposes natural
conditions on certain -invariants
Local cartography of persistent organic pollutants (dioxins, PCB) concentrations in soils of three French departments. How to define background concentrations?
International audienceAs part of the Regional Health Plan for the Rhône-Alpes area (France), a cartography of soil contamination by persistent organic pollutants (dioxins/furans (PCDD/PCDF) and polychlorinated biphenyls (PCB)) was undertaken in order to define the background concentrations of soils located away from point source pollution. In the natural environment, PCDD/PCDF and PCB comes from air pollution and accumulate in the upper part of the soils. To define the background concentration of persistent organic pollutants from diffuse atmospheric origin in soils, sampling was carried out within the first 5 centimeters of soils that have been very little anthropized and untilled for more than 15 years. In such soils mixing and dilution of the pollutants is very limited. 170 samples were collected following a systematic plan of grid type (mesh of 8 x 8 km) in an area of 14 000km 2 , avoiding soil of high altitude and from urban area. Beyond their total concentration, the ratio of the congeners of PCBs (7 indicators and 12 dioxin-like) and of the 17 dioxins/furans was also used for interpretation. As expected, the concentrations in pollutants are globally lower in the rural zones than in the more industrialized ones. However, the pollutants are relatively enriched in valleys, confirming that the meteorological conditions and the local topography play a significant role in the repartition of the diffuse atmospheric pollution. For the vast majority of samples, even some of those presenting the highest total concentration, the ratio of the various congeners argues for an ancient origin of the contamination. All studies at the French or European level of the atmospheric concentration of organic pollutants indicate a progressive decrease in emissions of these contaminants for about 20 years. However, the soils have been receptors since a long time and such pollutants have accumulated. The congeners ratio give evolved signature of pollution indicating, on one hand, it is mainly due to past activities but, on the other hand, indicate that it will persist because of its high stability. These results show the importance of knowing the spatial distribution of the concentrations of PCDD/PCDF and PCB and taking into account the signature of their congeners when defining the reference value of background concentration which are applied to distinguish a recent point source pollution
Spectre automorphe des vari\'et\'es hyperboliques et applications topologiques
This book is made of two parts. The first is concerned with the differential
form spectrum of congruence hyperbolic manifolds. We prove Selberg type
theorems on the first eigenvalue of the laplacian on differential forms. The
method of proof is representation theoritic, we hope the different chapters may
as well serve as an introduction to the modern theory of automorphic forms and
its application to spectral questions. The second part of the book is of a more
differential geometric flavor, a new kind of lifting of cohomology classes is
proved.Comment: 237 pages, book (in french
Short-term endothelin receptor blockade with tezosentan has both immediate and long-term beneficial effects in rats with myocardial infarction
AbstractObjectivesWe investigated the effects of short-term tezosentan treatment on cardiac function, pulmonary edema and long-term evolution of heart failure (HF) in a rat model of myocardial infarction (MI).BackgroundEndothelin (ET) may play a major role in the progression from MI to HF. Tezosentan is a new dual ETA/ETBreceptor antagonist.MethodsRats were subjected to coronary artery ligation and were treated with either vehicle or tezosentan (10 mg/kg IV bolus) at 1 h and 24 h after MI. Cardiac hemodynamics and lung weight were measured at 48 h after MI. Survival was assessed over a five-month period.ResultsAt 48 h after ligation, vehicle-treated rats developed HF, as evidenced by a marked increase in left ventricular end-diastolic pressure (LVEDP), reduction in dP/dtmaxand mean arterial pressure (MAP), and development of pulmonary edema. Tezosentan treatment attenuated the increase in LVEDP and in lung weight and slightly reduced MAP without affecting dP/dtmax. Infarct size was not modified by tezosentan. Despite the fact that treatment with tezosentan was stopped after 24 h, the initial tezosentan administration significantly reduced cardiac hypertrophy (22%) and decreased mortality by 51% at five months (50% survival vs. 19% survival in vehicle-treated rats, p < 0.001).ConclusionsTezosentan administered during the first day after MI in rats, in addition to improving acutely hemodynamic conditions, markedly increases long-term survival. This increase is associated with a decrease of pulmonary edema and prevention of cardiac hypertrophy. Tezosentan could be a safe and useful therapeutic agent in the prevention and treatment of ischemic HF
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