Ghost free dual vector theories in 2+1 dimensions

We explore here the issue of duality versus spectrum equivalence in abelian vector theories in 2+1 dimensions. Specifically we examine a generalized self-dual (GSD) model where a Maxwell term is added to the self-dual model. A gauge embedding procedure applied to the GSD model leads to a Maxwell-Chern-Simons (MCS) theory with higher derivatives. We show that the latter contains a ghost mode contrary to the original GSD model. On the other hand, the same embedding procedure can be applied to $N_f$ fermions minimally coupled to the self-dual model. The dual theory corresponds to $N_f$ fermions with an extra Thirring term coupled to the gauge field via a Pauli-like term. By integrating over the fermions at $N_f\to\infty$ in both matter coupled theories we obtain effective quadratic theories for the corresponding vector fields. On one hand, we have a nonlocal type of the GSD model. On the other hand, we have a nonlocal form of the MCS theory. It turns out that both theories have the same spectrum and are ghost free. By figuring out why we do not have ghosts in this case we are able to suggest a new master action which takes us from the local GSD to a nonlocal MCS model with the same spectrum of the original GSD model and ghost free. Furthermore, there is a dual map between both theories at classical level which survives quantum correlation functions up to contact terms. The remarks made here may be relevant for other applications of the master action approach.Comment: 15 pages, 1 figur

Byrsonima Crassa Niedenzu (ik): Antimicrobial Activity And Chemical Study

The methanolic extract of leaves from Byrsonima crassa, a Brazilian medicinal plant, was analyzed by CC and HPLC. Four constituents were isolated and identified as quercetin, methyl gallate, (-)-epigallocatechin gallate and quercetin-3-O-(2″-galloyl)-α-L-arabinopyranoside. The methanolic and hydromethanolic extract, as well as fractions, were evaluated regarding their possible antimicrobial activity using in vitro methods. Results showed that both extracts and fractions exhibited significant antimicrobial activity against all tested strains.2617175Agrawal, P.K., (1989) Carbon 13NMR of Flavonoids, , Amsterdam:ElsevierAlzoreky, N.S., Nakahara, K., Antibacterial activity of extracts from some edible plants commonly consumed in Asia (2003) Int J Food Microbiol, 80, pp. 223-230Amarqiuise, A., Che, C.T., Bejar, E., Malone, M.H., Fong, H.H.S., A New Glycolipid from Byrsonima crassifolia (1994) Planta Med, 60, pp. 85-86Basile, A., Sorbo, S., Giordano, S., Ricciardi, L., Ferrara, S., Montesano, D., Cobianchi, R.C., Ferrara, L., Antibacterial and allelopathic activity of extract from Castanea sativa leaves (2000) Fitoterapia, 71, pp. S110-S116Bauer, A.W., Kirby, M.D.K., Sherries, J.C., Truck, M., Antibiotic susceptibilities testing by standard single disc diffusion method (1966) Am J Clin Pathol, 45, pp. 493-496Bejar, E., Amarquaye, A., Che, C.T., Malone, M.H., Fong, H.H.S., Constituents of Byrsonima crassifolia and their spasmogenic activity (1995) Int J Pharmacog, 33, pp. 25-32Binutu, O.A., Cordell, G.A., Gallic acid derivatives from Mezoneuron benthamianum leaves (2000) Pharm Biol, 38, pp. 284-286Djipa, C.D., Delmee, M., Quetin-Leclercq, J., Antimicrobial activity of bark extracts of Syzygium jambos (L.) Alston (Myrtaceae) (2000) J Ethnopharmacol, 71, pp. 307-313Geiss, F., Heinrich, M., Hunkler, D., Rimpler, H., Heinrich, M., Proanthocyanidins with (+)-epicatechin units from Byrsonima crassifolia bark (1995) Phytochemistry, 39, pp. 635-643Gottlieb, O.R., Henriques Mendes, P., Taveira Magalhães, M., Triterpenoids from Byrsonima verbascifolia (1975) Phytochemistry, 14, pp. 1456-1456Harborne, J.B., (1996) The Flavonoids: Advances in Research since 1986, , New York:Chapman & HallLopez, A., Hudson, J.B., Towers, G.H.N., Antiviral and antimicrobial activities of Colombian medicinal plants (2001) J Ethnopharmacol, 77, pp. 189-196Martínez-Vasquéz, M., González-Esquinca, A.R., Cazares Luna, L., Moreno Gutiérrez, M.N., García-Argáez, A.N., Antimicrobial activity of Byrsonima crassifolia (L.) H.B.K (1999) J Ethnopharmacol, 66, pp. 79-82Mendes, C.C., Cruz, F.G., David, J.M., Nascimento, I.P., David, J.P., Triterpenes esterified with fatty acid and triterpene acids isolated from Byrsonima microphylla (1999) Quím Nova, 22, pp. 185-188Nascimento, G.G.F., Locatelli, J., Freitas, P.C., Silva, G.L., Antibacterial activity of plants extracts and phytochemicals on antibiotic-resistant bacteria (2000) Braz J Microbiol, 31, pp. 247-256(2003) Performance Standards for Antimicrobial Disc Susceptibility Tests, , Approved Standard M2-A7, Pennsylvania:WaynePenna, C., Marino, S., Vivot, E., Cruanes, M.C., Munoz, J.D., Cruanes, J., Ferraro, G., Martino, V., Antimicrobial activity of Argentine plants used in the treatment of infectious diseases. Isolation of active compounds from Sebastiania brasiliensis (2001) J Ethnopharmacol, 77, pp. 37-40Pretorius, J.C., Magama, S., Zietsman, P.C., Purification and identification of antibacterial compounds from Euclea crispa subsp crispa (Ebenaceae) leaves (2003) S Afr J Bot, 69, pp. 579-586Rastrelli, L., De Tommasi, N., Berger, I., Caceres, A., Saravia, A., De Simone, F., Glycolipids from Byrsonima crassifolia (1997) Phytochemistry, 45, pp. 647-650Sannomiya, M., Rodrigues, C.M., Coelho, R.G., Santos, L.C., Hiruma-Lima, C.A., Souza Brito, A.R.M., Vilegas, W., Application of preparative high-speed counter-current chromatography for the separation of flavonoids from the leaves of Byrsonima crassa Niedenzu (IK) (2004) J Chromatogr A, 1035, pp. 47-51Sannomiya, M., Fonseca, V.B., Da Silva, M.A., Rocha, L.R.M., Dos Santos, L.C., Souza, H.C.A., Brito, A.R.M., Vilegas, W., Flavonoids and antiulcerogenic activity from Byrsonima crassa leaves extracts (2005) J Ethnopharmacol, 97, pp. 1-6Silva, S.R., Silva, A.P., Munhoz, C.B., Silva Jr., M.C., Medeiros, M.B., (2001) Guia de Plantas Do Cerrado Utilizadas Na Chapada Dos Veadeiros, , Brasília:WWF58pSrinivasan, D., Nathan, S., Suresh, T., Perumalsamy, P.L., Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine (2001) J Ethnopharmacol, 74, pp. 217-220Wagner, H., Bladt, H., Zgainski, E.M., (1984) Plant Drug Analysis, , Berlin:Springer320

On the relation of Thomas rotation and angular velocity of reference frames

In the extensive literature dealing with the relativistic phenomenon of Thomas rotation several methods have been developed for calculating the Thomas rotation angle of a gyroscope along a circular world line. One of the most appealing concepts, introduced in \cite{rindler}, is to consider a rotating reference frame co-moving with the gyroscope, and relate the precession of the gyroscope to the angular velocity of the reference frame. A recent paper \cite{herrera}, however, applies this principle to three different co-moving rotating reference frames and arrives at three different Thomas rotation angles. The reason for this apparent paradox is that the principle of \cite{rindler} is used for a situation to which it does not apply. In this paper we rigorously examine the theoretical background and limitations of applicability of the principle of \cite{rindler}. Along the way we also establish some general properties of {\it rotating reference frames}, which may be of independent interest.Comment: 14 pages, 2 figure

Atorvastatin attenuation of ABCB1 expression is mediated by microRNA miR-491-3p in Caco-2 cells

AimAtorvastatin, a HMG-CoA reductase inhibitor, used in the treatment of hypercholesterolemia, has been previously shown to regulate ABCB1 expression in vivo and in vitro. We hypothesized that the statin could regulate gene expression of ABCB1 transporter via microRNAs.MethodsExpression of microRNAs and ABCB1 mRNA was examined in atorvastatin-treated and control cells using real-time PCR. miR-491-3P mimic and inhibitor were transfected in Caco-2 and ABCB1 expression was monitored by western blot and real-time PCR.ResultsIn HepG2 cells, none of the microRNAs predicted to target ABCB1 3'UTR was regulated by atorvastatin treatment. In agreement with this, ABCB1 3'UTR activity was not modulated in HepG-2 cells after 48h-treatment as measured by luciferase assay. In Caco-2 cells, atorvastatin treatment provoked a decrease in luciferase activity and, accordingly, miR-491-3p was upregulated about 2.7 times after 48h-statin treatment. Luciferase analysis of miR-491-3p with a mimetic or inhibitor of miR-491-3p revealed that this microRNA could target ABCB1 3'UTR, as after miR-491-3p inhibition, ABCB1 levels were increased by two-fold, and miR-491-3p superexpression decreased ABCB1 3'UTR activity. Finally, functional analysis revealed that treatment with miR-491-3p inhibitor could reverses atorvastatin attenuation of ABCB1 (Pg-p) protein levels.ConclusionOur results suggest atorvastatin control ABCB1 expression via miR-491-3p in Caco-2 cells. This finding may be an important mechanism of statin drug-drug interaction, since common concomitant drugs used in the prevention of cardiovascular diseases are ABCB1 substrates

Some anisotropic universes in the presence of imperfect fluid coupling with spatial curvature

We consider Bianchi VI spacetime, which also can be reduced to Bianchi types VI0-V-III-I. We initially consider the most general form of the energy-momentum tensor which yields anisotropic stress and heat flow. We then derive an energy-momentum tensor that couples with the spatial curvature in a way so as to cancel out the terms that arise due to the spatial curvature in the evolution equations of the Einstein field equations. We obtain exact solutions for the universes indefinetly expanding with constant mean deceleration parameter. The solutions are beriefly discussed for each Bianchi type. The dynamics of the models and fluid are examined briefly, and the models that can approach to isotropy are determined. We conclude that even if the observed universe is almost isotropic, this does not necessarily imply the isotropy of the fluid (e.g., dark energy) affecting the evolution of the universe within the context of general relativity.Comment: 17 pages, no figures; to appear in International Journal of Theoretical Physics; in this version (which is more concise) an equation added, some references updated and adde

Bianchi type II models in the presence of perfect fluid and anisotropic dark energy

Spatially homogeneous but totally anisotropic and non-flat Bianchi type II cosmological model has been studied in general relativity in the presence of two minimally interacting fluids; a perfect fluid as the matter fluid and a hypothetical anisotropic fluid as the dark energy fluid. The Einstein's field equations have been solved by applying two kinematical ans\"{a}tze: we have assumed the variation law for the mean Hubble parameter that yields a constant value of deceleration parameter, and one of the components of the shear tensor has been considered proportional to the mean Hubble parameter. We have particularly dwelled on the accelerating models with non-divergent expansion anisotropy as the Universe evolves. Yielding anisotropic pressure, the fluid we consider in the context of dark energy, can produce results that can be produced in the presence of isotropic fluid in accordance with the \Lambda CDM cosmology. However, the derived model gives additional opportunities by being able to allow kinematics that cannot be produced in the presence of fluids that yield only isotropic pressure. We have obtained well behaving cases where the anisotropy of the expansion and the anisotropy of the fluid converge to finite values (include zero) in the late Universe. We have also showed that although the metric we consider is totally anisotropic, the anisotropy of the dark energy is constrained to be axially symmetric, as long as the overall energy momentum tensor possesses zero shear stress.Comment: 15 pages; 5 figures; matches the version published in The European Physical Journal Plu

Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution

A new class of FLRW cosmological models with time-evolving fundamental parameters should emerge naturally from a description of the expansion of the universe based on the first principles of quantum field theory and string theory. Within this general paradigm, one expects that both the gravitational Newton's coupling, G, and the cosmological term, Lambda, should not be strictly constant but appear rather as smooth functions of the Hubble rate. This scenario ("running FLRW model") predicts, in a natural way, the existence of dynamical dark energy without invoking the participation of extraneous scalar fields. In this paper, we perform a detailed study of these models in the light of the latest cosmological data, which serves to illustrate the phenomenological viability of the new dark energy paradigm as a serious alternative to the traditional scalar field approaches. By performing a joint likelihood analysis of the recent SNIa data, the CMB shift parameter, and the BAOs traced by the Sloan Digital Sky Survey, we put tight constraints on the main cosmological parameters. Furthermore, we derive the theoretically predicted dark-matter halo mass function and the corresponding redshift distribution of cluster-size halos for the "running" models studied. Despite the fact that these models closely reproduce the standard LCDM Hubble expansion, their normalization of the perturbation's power-spectrum varies, imposing, in many cases, a significantly different cluster-size halo redshift distribution. This fact indicates that it should be relatively easy to distinguish between the "running" models and the LCDM cosmology using realistic future X-ray and Sunyaev-Zeldovich cluster surveys.Comment: Version published in JCAP 08 (2011) 007: 1+41 pages, 6 Figures, 1 Table. Typos corrected. Extended discussion on the computation of the linearly extrapolated density threshold above which structures collapse in time-varying vacuum models. One appendix, a few references and one figure adde

Conformal linear gravity in de Sitter space II

From the group theoretical point of view, it is proved that the theory of linear conformal gravity should be written in terms of a tensor field of rank-3 and mixed symmetry [Binegar, et al, Phys. Rev. D 27, (1983) 2249]. We obtained such a field equation in de Sitter space [Takook, et al, J. Math. Phys. 51, (2010) 032503]. In this paper, a proper solution to this equation is obtained as a product of a generalized polarization tensor and a massless scalar field and then the conformally invariant two-point function is calculated. This two-point function is de Sitter invariant and free of any pathological large-distance behavior.Comment: 16 pages, no figure, published versio

Non-vacuum Solutions of Bianchi Type VI_0 Universe in f(R) Gravity

In this paper, we solve the field equations in metric f(R) gravity for Bianchi type VI_0 spacetime and discuss evolution of the expanding universe. We find two types of non-vacuum solutions by taking isotropic and anisotropic fluids as the source of matter and dark energy. The physical behavior of these solutions is analyzed and compared in the future evolution with the help of some physical and geometrical parameters. It is concluded that in the presence of isotropic fluid, the model has singularity at $\tilde{t}=0$ and represents continuously expanding shearing universe currently entering into phantom phase. In anisotropic fluid, the model has no initial singularity and exhibits the uniform accelerating expansion. However, the spacetime does not achieve isotropy as $t\rightarrow\infty$ in both of these solutions.Comment: 20 pages, 5 figures, accepted for publication in Astrophys. Space Sc