Macroclumping as solution of the discrepancy between H{\alpha} and P v mass loss diagnostics for O-type stars

Recent studies of O-type stars demonstrated that discrepant mass-loss rates are obtained when different diagnostic methods are employed - fitting the unsaturated UV resonance lines (e.g. P v) gives drastically lower values than obtained from the H{\alpha} emission. Wind clumping may be the main cause for this discrepancy. In a previous paper, we have presented 3-D Monte-Carlo calculations for the formation of scattering lines in a clumped stellar wind. In the present paper we select five O-type supergiants (from O4 to O7) and test whether the reported discrepancies can be resolved this way. In the first step, the analyses start with simulating the observed spectra with Potsdam Wolf-Rayet (PoWR) non-LTE model atmospheres. The mass-loss rates are adjusted to fit best to the observed H{\alpha} emission lines. For the unsaturated UV resonance lines (i.e. P v) we then apply our 3-D Monte-Carlo code, which can account for wind clumps of any optical depths, a non-void inter-clump medium, and a velocity dispersion inside the clumps. The ionization stratifications and underlying photospheric spectra are adopted from the PoWR models. From fitting the observed resonance line profiles, the properties of the wind clumps are constrained. Our results show that with the mass-loss rates that fit H{\alpha} (and other Balmer and He II lines), the UV resonance lines (especially the unsaturated doublet of P v) can also be reproduced without problem when macroclumping is taken into account. There is no need to artificially reduce the mass-loss rates, nor to assume a sub-solar phosphorus abundance or an extremely high clumping factor, contrary to what was claimed by other authors. These consistent mass-loss rates are lower by a factor of 1.3 to 2.6, compared to the mass-loss rate recipe from Vink et al. Macroclumping resolves the previously reported discrepancy between H{\alpha} and P v mass-loss diagnostics.Comment: 18 pages, 14 figures, 5 tables, accepted for publication in Astrononomy & Astrophysic

Gravitational memory of natural wormholes

A traversable wormhole solution of general scalar-tensor field equations is presented. We have shown, after a numerical analysis for the behavior of the scalar field of Brans-Dicke theory, that the solution is completely singularity--free. Furthermore, the analysis of more general scalar field dependent coupling constants indicates that the gravitational memory phenomenon may play an important role in the fate of natural wormholes.Comment: 14 pages revtex, 1 ps figur

The f0(1370)f_0(1370), f0(1710)f_0(1710), f2(1270)f_2(1270), f2′(1525)f_2'(1525), and K2∗(1430)K_2^*(1430) as dynamically generated states from vector meson - vector meson interaction

We report on some recent developments in understanding the nature of the low-lying mesonic resonances $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f_2'(1525)$, and $K_2^*(1430)$. In particular we show that these five resonances can be dynamically generated from vector meson--vector meson interaction in a coupled-channel unitary approach, which utilizes the phenomenologically very successful hidden-gauge Lagrangians to produce the interaction kernel between two vector mesons, which is then unitarized by the Bethe-Salpeter-equation method. The data on the strong decay branching ratios, total decay widths, and radiative decay widths of these five states, and on related $J/\psi$ decay processes can all be well described by such an approach. We also make predictions, compare them with the results of earlier studies, and highlight observables that if measured can be used to distinguish different pictures of these resonances.Comment: 9 pages; Invited talk at workshop CHIRAL'10, Valencia (Spain), June 21-24, 201

Spatio-temporal vortex beams and angular momentum

We present a space-time generalization of the known spatial (monochromatic) wave vortex beams carrying intrinsic orbital angular momentum (OAM) along the propagation direction. Generic spatio-temporal vortex beams are polychromatic and can carry intrinsic OAM at an arbitrary angle to the mean momentum. Applying either (i) a transverse wave-vector shift or (ii) a Lorentz boost to a monochromatic Bessel beam, we construct a family of either (i) time-diffracting or (ii) non-diffracting spatio-temporal Bessel beams, which are exact solutions of the Klein-Gordon wave equations. The proposed spatio-temporal OAM states are able to describe either photon or electron vortex states (both relativistic and nonrelativistic), and can find applications in particle collisions, optics of moving media, quantum communications, and astrophysics.Comment: 9 pages, 6 figures, to appear in Phys. Rev.

Multiterminal conductance of a floquet topological insulator

We report on simulations of the dc conductance and quantum Hall response of a Floquet topological insulator using Floquet scattering theory. Our results reveal that laser-induced edge states lead to quantum Hall plateaus once imperfect matching with the nonilluminated leads is lessened. The magnitude of the Hall plateaus, however, is not directly related to the number and chirality of all the edge states at a given energy, as usual. Instead, the plateaus are dominated by those edge states adding to the time-averaged density of states. Therefore, the dc quantum Hall conductance of a Floquet topological insulator is not directly linked to topological invariants of the full Floquet bands.publishedVersionFil: Foa Torres, Luis Eduardo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Foa Torres, Luis Eduardo Francisco. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Pérez Piskunow, Pablo Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Pérez Piskunow, Pablo Matías. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Balseiro, Carlos A. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina.Fil: Balseiro, Carlos A. Comisión Nacional de Energía Atómica. Instituto Balseiro; Argentina.Fil: Balseiro, Carlos A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Usaj, Gonzalo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina.Fil: Usaj, Gonzalo. Comisión Nacional de Energía Atómica. Instituto Balseiro; Argentina.Fil: Usaj, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Física de los Materiales Condensado

Geometrothermodynamics

We present the fundamentals of geometrothermodynamics, an approach to study the properties of thermodynamic systems in terms of differential geometric concepts. It is based, on the one hand, upon the well-known contact structure of the thermodynamic phase space and, on the other hand, on the metric structure of the space of thermodynamic equilibrium states. In order to make these two structures compatible we introduce a Legendre invariant set of metrics in the phase space, and demand that their pullback generates metrics on the space of equilibrium states. We show that Weinhold's metric, which was introduced {\it ad hoc}, is not contained within this invariant set. We propose alternative metrics which allow us to redefine the concept of thermodynamic length in an invariant manner and to study phase transitions in terms of curvature singularities.Comment: Revised version, to be published in Jour. Math. Phy

Estimação de parâmetros genéticos para peso ao nascer em bovinos da raça Canchim avaliados sob diferentes modelos animais.

Foram utilizadas 18.215 observações de peso ao nascer de bovinos da raça Canchim criados em todo o Brasil, para estimar parâmetros genéticos para essa caracteristica utilizando-se quatro diferentes modelos animais. Nestes modelos foram considerados os efeitos fixos de grupo de contemporâneos (fazenda, ano e época de nascimento e sexo) e as covariáveis porcentagens de Charolês no animal e na mãe e porcentagem de heterozigose na mãe (efeito linear) e idade da vaca ao parto (efeitos linear e quadrático). Os efeitos aleatórios considerados foram os efeitos genéticos aditivo direto e materno e de ambiente permanente materno em diferentes combinações. Para a estimação dos parâmetros, os dados foram analisados pelo método da máxima verossimilhança restrita livre de derivadas e o teste de razão de verossimilhança (LRT) foi utilizado para a comparação dos modelos. O modelo completo (efeitos genéticos aditivo direto e materno e de ambiente permanente) foi o mais adequado, resultando nas seguintes estimativas de parâmetros: 0,30; 0,05 e 0,05 para a herdabilidade direta, herdabilidade materna e fração da variância atribuída ao ambiente permanente, respectivamente. A correlação entre os efeitos aditivos direto e materno foi próxima de zero

Reduced ratio of protective versus proinflammatory cytokine responses to commensal bacteria in HLA-B27 transgenic rats

Germ-free HLA-B27 transgenic (TG) rats do not develop colitis, but colonization with specific pathogen-free (SPF) bacteria induces colitis accompanied by immune activation. To study host-dependent immune responses to commensal caecal bacteria we investigated cytokine profiles in mesenteric lymph node (MLN) cells from HLA-B27 TG versus nontransgenic (non-TG) littermates after in vitro stimulation with caecal bacterial lysates (CBL). Supernatants from CBL-stimulated unseparated T- or B- cell-depleted MLN cells from HLA-B27 TG and non-TG littermates were analysed for IFN-γ, IL-12, TNF, IL-10 and TGF-β production. Our results show that unfractionated TG MLN cells stimulated with CBL produced more IFN-γ, IL-12 and TNF than did non-TG MLN cells. In contrast, CBL-stimulated non-TG MLN cells produced more IL-10 and TGF-β. T cell depletion abolished IFN-γ and decreased IL-12 production, but did not affect IL-10 and TGF-β production. Conversely, neither IL-10 nor TGF-β was produced in cultures of B cell-depleted MLN. In addition, CD4+ T cells enriched from MLN of HLA-B27 TG but not from non-TG rats produced IFN-γ when cocultured with CBL-pulsed antigen presenting cells from non-TG rats. Interestingly, IL-10 and TGF-β, but not IFN-γ, IL-12 and TNF were produced by MLN cells from germ-free TG rats. These results indicate that the colitis that develops in SPF HLA-B27 TG rats is accompanied by activation of IFN-γ-producing CD4+ T cells that respond to commensal bacteria. However, B cell cytokine production in response to components of commensal intestinal microorganisms occurs in the absence of intestinal inflammation

Deformation of quantum mechanics in fractional-dimensional space

A new kind of deformed calculus (the D-deformed calculus) that takes place in fractional-dimensional spaces is presented. The D-deformed calculus is shown to be an appropriate tool for treating fractional-dimensional systems in a simple way and quite analogous to their corresponding one-dimensional partners. Two simple systems, the free particle and the harmonic oscillator in fractional- dimensional spaces are reconsidered into the framework of the D-deformed quantum mechanics. Confined states in a D-deformed quantum well are studied. D-deformed coherent states are also found.Comment: 12 pages, some misprints have been corrected, two figures are adde