916 research outputs found
Solving the Boltzmann equation in N log N
In [C. Mouhot and L. Pareschi, "Fast algorithms for computing the Boltzmann
collision operator," Math. Comp., to appear; C. Mouhot and L. Pareschi, C. R.
Math. Acad. Sci. Paris, 339 (2004), pp. 71-76], fast deterministic algorithms
based on spectral methods were derived for the Boltzmann collision operator for
a class of interactions including the hard spheres model in dimension three.
These algorithms are implemented for the solution of the Boltzmann equation in
two and three dimension, first for homogeneous solutions, then for general non
homogeneous solutions. The results are compared to explicit solutions, when
available, and to Monte-Carlo methods. In particular, the computational cost
and accuracy are compared to those of Monte-Carlo methods as well as to those
of previous spectral methods. Finally, for inhomogeneous solutions, we take
advantage of the great computational efficiency of the method to show an
oscillation phenomenon of the entropy functional in the trend to equilibrium,
which was suggested in the work [L. Desvillettes and C. Villani, Invent. Math.,
159 (2005), pp. 245-316].Comment: 32 page
Catalogue of the Eocene mammal types of the Natural History Museum Basel
This catalogue presents a list of the Eocene mammalian type specimens
held in the collection of the Natural History Museum Basel (Naturhistorisches
Museum Basel, hereafter NMB). After a close inspection of the
very rich Eocene collection (several tens of thousands of specimens), a
total of 51 valid holotypes (plus 16 invalid species) were identified together
with 21 valid lectotypes and several hundreds paratypes, paralectotypes
and syntypes. These types belong to 123 originally described species, of
which 99 are still valid, 30 having been moved to another genus
Litt.et.Maths : explorer des albums de littérature dans une perspective interdisciplinaire français et mathématiques
Le français et les mathĂ©matiques, tant au primaire quâau secondaire, sont les deux disciplines centrales des programmes de formation actuels. Ces disciplines scolaires occupent plus de 60 % du temps dâenseignement, dâapprentissage et dâĂ©valuation, et elles sont sources des principales difficultĂ©s
et des principaux troubles dâapprentissage des Ă©lĂšves. Afin de rĂ©concilier ces deux disciplines souvent considĂ©rĂ©es comme opposĂ©es et difficiles, et de les faire apprĂ©cier par des Ă©lĂšves parfois rĂ©ticents, nous avons mis sur pied Ă lâautomne 2012 un laboratoire interdisciplinaire littĂ©rature et mathĂ©matiques
nommé Litt.et.Maths
Motif affinity and mass spectrometry proteomic approach for the discovery of cellular AMPK targets: identification of mitochondrial fission factor as a new AMPK substrate
AMP-activated protein kinase (AMPK) is a key cellular energy sensor and regulator of metabolic homeostasis. Although it is best known for its effects on carbohydrate and lipid metabolism, AMPK is implicated in diverse cellular processes, including mitochondrial biogenesis, autophagy, and cell growth and proliferation. To further our understanding of energy homeostasis through AMPK-dependent processes, the design and application of approaches to identify and characterise novel AMPK substrates are invaluable. Here, we report an affinity proteomicstrategy for the discovery and validation of AMPK targets using an antibody to isolate proteins containing the phospho-AMPK substrate recognition motif from hepatocytes that had been treated with pharmacological AMPK activators. We identified 57 proteins that were uniquely enriched in the activator-treated hepatocytes, but were absent in hepatocytes lacking AMPK. We focused on two candidates, cingulin and mitochondrial fission factor (MFF), and further characterised/validated them as AMPK-dependent targets by immunoblotting with phosphorylation site-specific antibodies. A small-molecule AMPK activator caused transient phosphorylation of endogenous cingulin at S137 in intestinal Caco2 cells. Multiple splice-variants of MFF appear to express in hepatocytes and we identified a common AMPK-dependent phospho-site (S129) in all the 3 predominant variants spanning the mass range and a short variant-specific site (S146). Collectively, our proteomic-based approach using a phospho-AMPK substrate antibody in combination with genetic models and selective AMPK activators will provide a powerful and reliable platform for identifying novel AMPK-dependent cellular targets
Polychronous Interpretation of Synoptic, a Domain Specific Modeling Language for Embedded Flight-Software
The SPaCIFY project, which aims at bringing advances in MDE to the satellite
flight software industry, advocates a top-down approach built on a
domain-specific modeling language named Synoptic. In line with previous
approaches to real-time modeling such as Statecharts and Simulink, Synoptic
features hierarchical decomposition of application and control modules in
synchronous block diagrams and state machines. Its semantics is described in
the polychronous model of computation, which is that of the synchronous
language Signal.Comment: Workshop on Formal Methods for Aerospace (FMA 2009
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