Some remarks on the geometry of the Standard Map

We define and compute hyperbolic coordinates and associated foliations which provide a new way to describe the geometry of the standard map. We also identify a uniformly hyperbolic region and a complementary 'critical' region containing a smooth curve of tangencies between certain canonical 'stable' foliations.Comment: 25 pages, 11 figure

Patients with paroxysmal nocturnal hemoglobinuria have a high frequency of peripheral-blood T cells expressing activating isoforms of inhibiting superfamily receptors

Patients with paroxysmal nocturnal hemoglobinuria (PNH) have a large clonal population of blood cells deriving from hematopoietic stem cells (HSCs) deficient in glycosylphosphatidylinositol (GPI)-anchored surface molecules. A current model postulates that PNH arises through negative selection against normal HSCs exerted by autoreactive T cells, whereas PNH HSCs escape damage. We have investigated the inhibitory receptor superfamily (IRS) system in 13 patients with PNH. We found a slight increase in the proportion of T cells expressing IRS. In contrast to what applies to healthy donors, the engagement of IRS molecules on T cells from patients with PNH elicited a powerful cytolytic activity in a redirected killing assay, indicating that these IRSs belong to the activating type. This was confirmed by clonal analysis: 50% of IRS+ T-cell clones in patients with PNH were of the activating type, while only 5% were of the activating type in healthy donors. Moreover, the ligation of IRS induces (1) production of tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) and (2) brisk cytolytic activity against cells bearing appropriate IRS counter-ligands. In addition, these IRS+ T cells show natural killer (NK)-like cytolytic activity to which GPI- cells were less sensitive than GPI+ cells. Thus, T cells with NK-like features, expressing the activating isoforms of IRS, may include effector cells involved in the pathogenesis of PNH

Statistical Consequences of Devroye Inequality for Processes. Applications to a Class of Non-Uniformly Hyperbolic Dynamical Systems

In this paper, we apply Devroye inequality to study various statistical estimators and fluctuations of observables for processes. Most of these observables are suggested by dynamical systems. These applications concern the co-variance function, the integrated periodogram, the correlation dimension, the kernel density estimator, the speed of convergence of empirical measure, the shadowing property and the almost-sure central limit theorem. We proved in \cite{CCS} that Devroye inequality holds for a class of non-uniformly hyperbolic dynamical systems introduced in \cite{young}. In the second appendix we prove that, if the decay of correlations holds with a common rate for all pairs of functions, then it holds uniformly in the function spaces. In the last appendix we prove that for the subclass of one-dimensional systems studied in \cite{young} the density of the absolutely continuous invariant measure belongs to a Besov space.Comment: 33 pages; companion of the paper math.DS/0412166; corrected version; to appear in Nonlinearit

Solution of the structure of tetrameric human glucose 6-phosphate dehydrogenase by molecular replacement

Recombinant human glucose 6-phosphate dehydrogenase (G6PD) has been crystallized and its structure solved by molecular replacement. Crystals of the natural mutant R459L grow under similar conditions in space groups P212121 and C2221 with eight or four 515-residue molecules in the asymmetric unit, respectively. A non-crystallographic 222 tetramer was found in the C2221 crystal form using a 4 A resolution data set and a dimer of the large beta + alpha domains of the Leuconostoc mesenteroides enzyme as a search model. This tetramer was the only successful search model for the P212121 crystal form using data to 3 A. Crystals of the deletion mutant DeltaG6PD grow in space group F222 with a monomer in the asymmetric unit; 2.5 A resolution data have been collected. Comparison of the packing of tetramers in the three space groups suggests that the N-terminal tail of the enzyme prevents crystallization with exact 222 molecular symmetry.published_or_final_versio

Kernicterus by glucose-6-phosphate dehydrogenase deficiency: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Glucose-6-phosphate dehydrogenase deficiency is an X-linked recessive disease that causes acute or chronic hemolytic anemia and potentially leads to severe jaundice in response to oxidative agents. This deficiency is the most common human innate error of metabolism, affecting more than 400 million people worldwide.</p> <p>Case presentation</p> <p>Here, we present the first documented case of kernicterus in Panama, in a glucose-6-phosphate dehydrogenase-deficient newborn clothed in naphthalene-impregnated garments, resulting in reduced psychomotor development, neurosensory hypoacousia, absence of speech and poor reflex of the pupil to light.</p> <p>Conclusion</p> <p>Mutational analysis revealed the glucose-6-phosphate dehydrogenase Mediterranean polymorphic variant, which explained the development of kernicterus after exposition of naphthalene. As the use of naphthalene in stored clothes is a common practice, glucose-6-phosphate dehydrogenase testing in neonatal screening could prevent severe clinical consequences.</p

Geometry of expanding absolutely continuous invariant measures and the liftability problem

We show that for a large class of maps on manifolds of arbitrary finite dimension, the existence of a Gibbs-Markov-Young structure (with Lebesgue as the reference measure) is a necessary as well as sufficient condition for the existence of an invariant probability measure which is absolutely continuous measure (with respect to Lebesgue) and for which all Lyapunov exponents are positive.Comment: 21 pages; final versio