322 research outputs found

    On Gibbs measures for almost additive potentials

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    Given an almost additive sequence of continuous functions with bounded variation F={logfn}n=1\mathcal{F}=\{\log f_n\}_{n=1}^{\infty} on a subshift XX over finitely many symbols, we study properties of a function ff on XX such that limn1nlogfndμ=fdμ\lim_{n\to\infty}\frac{1}{n}\int \log f_n d\mu=\int f d\mu for every invariant measure μ\mu on XX. Under some conditions we construct a function ff on XX and study a relation between the property of F\mathcal{F} and some particular types of ff. We also study the case when F\mathcal{F} is weakly almost additive. As applications we study images of Gibbs measures for continuous functions under one-block factor maps. In order to study conditions for the image to be a Gibbs measure for a continuous function, we investigate a relation between the almost additivity of the sequences associated to relative pressure functions and the fiber-mixing property of a factor map.Comment: 17 page

    Markov partitions reflecting the geometry of x2,x3

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    We give an explicit geometric description of the ×2,×3\times2,\times3 system, and use his to study a uniform family of Markov partitions related to those of Wilson and Abramov. The behaviour of these partitions is stable across expansive cones and transitions in this behaviour detects the non-expansive lines

    Expression of kininogen, kallikrein and kinin receptor genes by rat cardiomyocytes

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    AbstractTo ascertain the existence of the kallikrein-kinin system in the heart, we have studied in vivo and in vitro whether rat cardiac tissue expresses kininogen, kallikrein and kinin receptor mRNAs. The reverse transcription-polymerase chain reaction demonstrated that the ventricular myocardium of adult male rats expressed mRNAs for T- and low-molecular-weight (L-) kininogens, tissue kallikreins such as true kallikrein and T-kininogenase, and bradykinin B2 receptor, but not those for high-molecular-weight kininogen and B1 receptor. Lipopolysaccharide (LPS; 0.5 mg/kg, i.v.) increased the levels of mRNA for T-kininogen at 12 h and the bradykinin B1 receptor at 24 h without affecting that for other components. All of these mRNAs for the kallikrein-kinin system were also detected in cultured cardiomyocytes derived from neonatal rat ventricles; dibutyryl cyclic AMP, LPS or inflammatory cytokines such as interleukin-1 and tumor necrosis factor, up-regulated mRNA expression of T-kininogen, T-kininogenase, or B1 receptor in these cells in vitro. These results suggest that there are two kinin-generating systems in rat myocardium comprising T-kininogen/T-kininogenase and L-kininogen/true kallikrein respectively, and that the former may be relatively important in inflammatory diseases or conditions in which cAMP levels increase in cardiomyocytes

    Polarization modulation of nanotrenches in GaN (0001)/(0001ˉ)(000\bar{1}) by surface hydrogenation

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    Using first-principles total-energy calculations within the framework of the density functional theory, we show that nanometer-scale trenches excavated in GaN with (0001) and (0001ˉ)(000\bar{1}) surfaces cause a variable electrostatic potential difference, which is tunable by controlling the hydrogen coverage of the surfaces. A positive potential difference of 3.53 V is induced between clean (0001) and (0001ˉ)(000\bar{1}) surfaces in nanotrenches, while a negative potential difference of −5.93 V is induced in nanotrenches with fully hydrogenated surfaces. The value of the potential difference strongly depends on the H coverage of the surfaces. Nanotrenches excavated in GaN with polar surfaces can supply electricity for various nanoscale devices consisting of molecules, clusters, and atoms inserted into the trenches

    Electron attachment to atomic hydrogen on the surface of liquid ⁴He

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    We demonstrate a possibility that helium surface electrons at cryogenic temperatures can be used as a new source of very low energy electrons. Since both electrons (e¯) and hydrogen atoms (H) are bound on liquid helium surface, two-dimensional mixture gas of these two species is available on the surface. We found that low energy collision of e¯ and H drives electron attachment to form a negative hydrogen ion (H¯) in the mixture. From our temperature dependence measurement of the reaction rate, it was found that another H atom participate in the reaction. Namely, the reaction is expressed as H + H + e¯ → H¯ + H. Possible reaction mechanisms are discussed in terms of direct three-body process and dissociative attachment process. Measurements in applied magnetic field (B) show that the reaction rate coefficient is suppressed as ~ B⁻². This implies that electron spin singlet collision is relevant for electron attachment
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