New Results on Holographic Three-Point Functions

We exploit a gauge invariant approach for the analysis of the equations governing the dynamics of active scalar fluctuations coupled to the fluctuations of the metric along holographic RG flows. In the present approach, a second order ODE for the active scalar emerges rather simply and makes it possible to use the Green's function method to deal with (quadratic) interaction terms. We thus fill a gap for active scalar operators, whose three-point functions have been inaccessible so far, and derive a general, explicitly Bose symmetric formula thereof. As an application we compute the relevant three-point function along the GPPZ flow and extract the irreducible trilinear couplings of the corresponding superglueballs by amputating the external legs on-shell.Comment: v2: reference added, typos corrected v3: sign convention for background changed, agrees with version published in JHE

Shadowing in photo-production : role of in-medium hadrons

We study the effects of in-medium hadronic properties on shadowing in photon-nucleus interactions in Glauber model as well as in the multiple scattering approach. A reasonable agreement with the experimental data is obtained in a scenario of downward spectral shift of the hadrons. Shadowing is found to be insensitive to the broadening of the spectral functions. An impact parameter dependent analysis of shadowing might shed more light on the role of in-medium properties of hadrons.Comment: Title modified; version to appear in PRC, Rapid Communication

Future non-linear stability for reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types II and VI0_0

Using the methods developed for the Bianchi I case we have shown that a boostrap argument is also suitable to treat the future non-linear stability for reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types II and VI$_0$. These solutions are asymptotic to the Collins-Stewart solution with dust and the Ellis-MacCallum solution respectively. We have thus generalized the results obtained by Rendall and Uggla in the case of locally rotationally symmetric Bianchi II spacetimes to the reflection symmetric case. However we needed to assume small data. For Bianchi VI$_0$ there is no analogous previous result.Comment: 30 page

Dipyridamole increases Cx43 expression in heart muscle cells through Adenosine 2A receptor/PKC pathway

Cx43, a predominant connexin in the heart, forms gap junctions (GJs) that facilitate electrical cell-cell coupling and hemichannels that represent a pathway for the exchange of ions and metabolites between cytoplasm and the extracellular milieu. Our recent results (1) demonstrated that an altered distribution and quantitative expression of factors involved in Cx43-made GJ regulation as Cx43, its phosphorylated form pS368-Cx43, PKC phosphorylated substrates, and adenosine 2A receptor (A2AR) are present in ventricular myocardium with left ventricular dysfunction. Moreover, dipyridamole treatment, which shows a mild protective role on left ventricular function, seems to act through re-modulating the expression and activation of these factors. The role of these factors on signal transduction cascade triggered by dipyridamole was evaluated in this study by pharmacological and immunoistochemical experiments using the rat cardiomyoblast cell line H9c2. The treatment of H9c2 cells with dipyridamole enhanced the expression of Cx43, A2AR and PKC activity while induced a decrease of pS368-Cx43. Interestingly, we found that the A2AR activation was a prerequisite for the effects of dipyridamole, in fact, the pre-treatment with CSC, a selective A2AR receptor antagonist, abolished its effects on the expression of these factors

Blow-up solutions for linear perturbations of the Yamabe equation

For a smooth, compact Riemannian manifold (M,g) of dimension N \geg 3, we are interested in the critical equation $$\Delta_g u+(N-2/4(N-1) S_g+\epsilon h)u=u^{N+2/N-2} in M, u>0 in M,$$ where \Delta_g is the Laplace--Beltrami operator, S_g is the Scalar curvature of (M,g), $h\in C^{0,\alpha}(M)$, and $\epsilon$ is a small parameter

Connexin 26 expression in mammalian cardiomyocytes

Connexins (Cxs) are a family of membrane-spanning proteins named according to their molecular weight. They have been known to form membrane channels mediating cell-cell communication, which play an essential role in the propagation of electrical activity throughout the heart. So far, expression of seven isoforms, namely Cx30.2, Cx37, Cx40, Cx43, Cx45, Cx46 and Cx57, have been found in cardiac myocytes (1,2). Cx26 has been described in a number of tissues but not yet in the heart, and its mutations are frequently associated with deafness and skin diseases (3,4). To our knowledge, the expression of Cx26 also in human, pig, rat and mouse cardiomyocytes has been demonstrated for the first time in the present study. Interestingly, this Cx was found as scattered throughout cell cytoplasm but not at level of the intercalated disks where the other cardiac Cxs are mainly located. Furthermore, in cardiomyocytes of a pig model of left ventricular dysfunction (LVD), Cx26 expression was modulated and dipyridamole treatment, which was previously demonstrated to have a protective action on left ventricular function (5), was associated to an increased Cx26 expression. Dipyridamole induced the same effect in cardiac rat cell line H9c2. For our study, paraffin embedded sections of human auricle, pig ventricle, mouse whole heart and H9c2 cells were used. Several methods were employed to test the expression of Cx26. In particular, different immunohistochemical and molecular biology techniques were performed by using two types of primary anti-Cx26 antibodies to ascertain the specificity of cardiomyocyte immunopositivity for Cx26 avoiding analysis-dependent artifacts

Bloom-Gilman duality of inelastic structure functions in nucleon and nuclei

The Bloom-Gilman local duality of the inelastic structure function of the proton, the deuteron and light complex nuclei is investigated using available experimental data in the squared four-momentum transfer range from 0.3 to 5 (GeV/c)**2. The results of our analysis suggest that the onset of the Bloom-Gilman local duality is anticipated in complex nuclei with respect to the case of the protonand the deuteron. A possible interpretation of this result in terms of a rescaling effect is discussed with particular emphasis to the possibility of reproducing the damping of the nucleon-resonance transitions observed in recent electroproduction data off nuclei.Comment: revised version, to appear in Physical Review

The Self Model and the Conception of Biological Identity in Immunology

The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity

Menus for Feeding Black Holes

Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.Comment: 27 pages. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher