27 research outputs found

    Topics in chaotic dynamics

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    Various kinematical quantities associated with the statistical properties of dynamical systems are examined: statistics of the motion, dynamical bases and Lyapunov exponents. Markov partitons for chaotic systems, without any attempt at describing ``optimal results''. The Ruelle principle is illustrated via its relation with the theory of gases. An example of an application predicts the results of an experiment along the lines of Evans, Cohen, Morriss' work on viscosity fluctuations. A sequence of mathematically oriented problems discusses the details of the main abstract ergodic theorems guiding to a proof of Oseledec's theorem for the Lyapunov exponents and products of random matricesComment: Plain TeX; compile twice; 30 pages; 140K Keywords: chaos, nonequilibrium ensembles, Markov partitions, Ruelle principle, Lyapunov exponents, random matrices, gaussian thermostats, ergodic theory, billiards, conductivity, gas.

    Near-infrared imaging of the host galaxies of three radio-loud quasars at z = 1.5

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    We present high spatial resolution near-infrared H-band (1.65 microns) images, taken with ISAAC on UT1 of ESO VLT, of three radio-loud quasars at z = 1.5, as a pilot study for imaging of a larger sample of radio-loud and radio-quiet quasars in the redshift range 1 < z < 2. We are able to clearly detect the host galaxy in two quasars (PKS 0000-177 and PKS 0348-120) and marginally in the third (PKS 0402-362). The host galaxies appear compact (average bulge scale-length R(e) = 4 kpc) and luminous (average M(H) = -27.6+-0.1). They are 2.5 mag more luminous than the typical galaxy luminosity (M*(H) = -25.0+-0.2), and are comparable to the hosts of low redshift radio-loud quasars (M(H) = -26), taking into account passive stellar evolution. Their luminosities are also similar to those of high redshift radio galaxies. All three quasars have at least one close companion galaxy at a projected distance < 50 kpc from the quasar, assuming they are at the same redshift.Comment: 11 pages, 2 figures. Accepted for publication in Astrophysical Journa

    Validation by RQ-PCR and flow cytometry of alpha-defensin 1-3 (DEFA 1-3) overexpression in relapsed and refractory acute lymphoblastic leucemia.

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    In spite of high cure rates and improved overall survival, 25% of pediatric patients with acute lymphoblastic leukemia (ALL) relapse after obtaining complete remission. Additionally a small proportion of patients are refractory and do not attain remission. Microarray expression analysis of matched diagnosis-relapse B-lineage ALL sample pairs identified DEFA1-3 as a potential marker of relapse. Here, validation of DEFA1-3 as a marker for therapy resistance is explored. DEFA1-3 expression was analysed by RQ-PCR in patient paired samples at diagnosis and relapse of 6 early-relapse (within 18 months) and 8 late-relapse (beyond 18 months) B-lineage ALL. Diagnostic samples of 19 patients with ALL who are in continuous complete remission (median time from diagnosis 47 month) and diagnostic samples of 5 refractory patients who had not achieved remission at day 35 of therapy were also analyzed. In addition, overexpression of \u3b1-defensin1-3 proteins in blast cells at relapse was analysed by flow cytometry. DEFA1-3 was overexpressed at relapse as compared to diagnosis in 12 of 14 samples. At diagnosis, the expression of DEFA1-3 was significantly higher in samples from refractory patients as compared to those of patients who are in CR and to those of patients who experienced late relapse. At diagnosis, patients who relapsed early after diagnosis could not be distinguished from refractory patients based on DEFA1-3 expression levels. Results suggest that high levels of DEFA1-3 mRNA and \u3b1-defensin1-3 protein expression are correlated with disease progression and failure of adequate response to conventional chemotherapy
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