Bayesian Analysis and Constraints on Kinematic Models from Union SNIa

The kinematic expansion history of the universe is investigated by using the 307 supernovae type Ia from the Union Compilation set. Three simple model parameterizations for the deceleration parameter (constant, linear and abrupt transition) and two different models that are explicitly parametrized by the cosmic jerk parameter (constant and variable) are considered. Likelihood and Bayesian analyses are employed to find best fit parameters and compare models among themselves and with the flat $\Lambda$CDM model. Analytical expressions and estimates for the deceleration and cosmic jerk parameters today ($q_0$ and $j_0$) and for the transition redshift ($z_t$) between a past phase of cosmic deceleration to a current phase of acceleration are given. All models characterize an accelerated expansion for the universe today and largely indicate that it was decelerating in the past, having a transition redshift around 0.5. The cosmic jerk is not strongly constrained by the present supernovae data. For the most realistic kinematic models the $1\sigma$ confidence limits imply the following ranges of values: $q_0\in[-0.96,-0.46]$, $j_0\in[-3.2,-0.3]$ and $z_t\in[0.36,0.84]$, which are compatible with the $\Lambda$CDM predictions, $q_0=-0.57\pm0.04$, $j_0=-1$ and $z_t=0.71\pm0.08$. We find that even very simple kinematic models are equally good to describe the data compared to the concordance $\Lambda$CDM model, and that the current observations are not powerful enough to discriminate among all of them.Comment: 13 pages. Matches published versio

Probing the course of cosmic expansion with a combination of observational data

We study the cosmic expansion history by reconstructing the deceleration parameter $q(z)$ from the SDSS-II type Ia supernova sample (SNIa) with two different light curve fits (MLCS2k2 and SALT-II), the baryon acoustic oscillation (BAO) distance ratio, the cosmic microwave background (CMB) shift parameter, and the lookback time-redshift (LT) from the age of old passive galaxies. Three parametrization forms for the equation of state of dark energy (CPL, JBP, and UIS) are considered. Our results show that, for the CPL and the UIS forms, MLCS2k2 SDSS-II SNIa+BAO+CMB and MLCS2k2 SDSS-II SNIa+BAO+CMB+LT favor a currently slowing-down cosmic acceleration, but this does not occur for all other cases, where an increasing cosmic acceleration is still favored. Thus, the reconstructed evolutionary behaviors of dark energy and the course of the cosmic acceleration are highly dependent both on the light curve fitting method for the SNIa and the parametrization form for the equation of state of dark energy.Comment: 19 pages, 6 figures, accepted for publication in JCA

Semi-empirical catalog of early-type galaxy-halo systems: dark matter density profiles, halo contraction and dark matter annihilation strength

With SDSS galaxy data and halo data from up-to-date N-body simulations we construct a semi-empirical catalog (SEC) of early-type systems by making a self-consistent bivariate statistical match of stellar mass (M_star) and velocity dispersion (sigma) with halo virial mass (M_vir). We then assign stellar mass profile and velocity dispersion profile parameters to each system in the SEC using their observed correlations with M_star and sigma. Simultaneously, we solve for dark matter density profile of each halo using the spherical Jeans equation. The resulting dark matter density profiles deviate in general from the dissipationless profile of NFW or Einasto and their mean inner density slope and concentration vary systematically with M_vir. Statistical tests of the distribution of profiles at fixed M_vir rule out the null hypothesis that it follows the distribution predicted by N-body simulations for M_vir ~< 10^{13.5-14.5} M_solar. These dark matter profiles imply that dark matter density is, on average, enhanced significantly in the inner region of halos with M_vir ~< 10^{13.5-14.5} M_solar supporting halo contraction. The main characteristics of halo contraction are: (1) the mean dark matter density within the effective radius has increased by a factor varying systematically up to ~ 3-4 at M_vir = 10^{12} M_solar, and (2) the inner density slope has a mean of ~ 1.3 with rho(r) ~ r^{-alpha} and a halo-to-halo rms scatter of rms(alpha) ~ 0.4-0.5 for 10^{12} M_solar ~< M_vir ~< 10^{13-14} M_solar steeper than the NFW profile (alpha=1). Based on our results we predict that halos of nearby elliptical and lenticular galaxies can, in principle, be promising targets for gamma-ray emission from dark matter annihilation.Comment: 43 pages, 20 figures, JCAP, revised and accepted versio

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination

Western blot detection of infectious bursal disease virus infection

In order to evaluate the use of a Western blot methodology for the diagnosis of infectious bursal disease virus (IBDV) infection, chickens were experimentally infected with IBDV strains and tested for the presence of viral antigens and antibodies by a blocking Western blot test (bWB). The viral proteins obtained from the bursa of Fabricius (BF) were transferred to a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the chicken sera obtained by heart puncture were used for the detection of these proteins. In order to eliminate nonspecific reactions, we used a rabbit anti-chicken serum (blocking tool). By the use of the bWB test, two distinct viral proteins of 43-kDa (VP2) and 32-kDa (VP3) were detected. We suggest the use of this methodology for the detection of IBDV infection in animals suspected of having IBDV reinfection and a chronic subclinical form of the disease. With the use of the rabbit anti-chicken sera for blocking, this method is practical, sensitive and less time consumin

Uso popular de plantas medicinais e perfil socioeconômico dos usuários: um estudo em área urbana em Ouro Preto, MG, Brasil

Este trabalho teve por objetivo identificar as plantas medicinais de uso popular e o perfil socioecon&#244;mico de seus usu&#225;rios em &#225;rea urbana de Ouro Preto, MG. O levantamento utilizou entrevistas semiestruturadas e amostragem aleat&#243;ria, perfazendo 10% das resid&#234;ncias. O grau de conhecimento sobre plantas medicinais foi medido pelo n&#250;mero de esp&#233;cies citadas. Analisou-se a rela&#231;&#227;o entre o saber popular sobre as plantas medicinais e caracter&#237;sticas socioecon&#244;micas dos entrevistados (renda, escolaridade, sexo, idade e forma de aquisi&#231;&#227;o do conhecimento). Foram questionadas 6.713 pessoas, onde mais de 90% usam plantas medicinais para se tratarem. Identificou-se 342 esp&#233;cies, reunidas em 94 fam&#237;lias. Para cada esp&#233;cie foram referidos os nomes populares, h&#225;bito, proced&#234;ncia, uso medicinal, parte usada, e forma de preparo. As principais mol&#233;stias tratadas com plantas foram: diarreia, ins&#244;nia, gripe, hidropisia, dist&#250;rbios hep&#225;ticos, renais e do trato respirat&#243;rio. H&#225; um grande n&#250;mero de esp&#233;cies nativas utilizadas. Dentre as ex&#243;ticas, a maioria &#233; de origem europeia. O uso m&#237;stico de esp&#233;cies, embora presente na cultura popular do munic&#237;pio, foi pouco citado. Algumas esp&#233;cies identificadas figuram na lista das esp&#233;cies amea&#231;adas de extin&#231;&#227;o. O grau de conhecimento sobre plantas medicinais pela popula&#231;&#227;o de Ouro Preto independe, tanto do n&#237;vel econ&#244;mico, como da escolaridade ou do sexo. A idade e a forma de aquisi&#231;&#227;o do conhecimento influenciam no saber popular das ervas medicinais. As pessoas com maior saber popular sobre as plantas adquiriram esses conhecimentos principalmente pelo costume familiar, por livros, ou por outras pessoas. Pessoas mais jovens conhecem menos esp&#233;cies medicinais que as mais idosas, sugerindo risco de perda desse conhecimento tradicional. A grande riqueza de plantas citadas neste trabalho denota a import&#226;ncia de estudos etnobot&#226;nicos no resgate do conhecimento tradicional em &#225;reas urbanas, tanto pelo seu valor hist&#243;rico-cultural, como pela import&#226;ncia cient&#237;fica