Cosmological constant constraints from observation-derived energy condition bounds and their application to bimetric massive gravity

Among the various possibilities to probe the theory behind the recent accelerated expansion of the universe, the energy conditions (ECs) are of particular interest, since it is possible to confront and constrain the many models, including different theories of gravity, with observational data. In this context, we use the ECs to probe any alternative theory whose extra term acts as a cosmological constant. For this purpose, we apply a model-independent approach to reconstruct the recent expansion of the universe. Using Type Ia supernova, baryon acoustic oscillations and cosmic-chronometer data, we perform a Markov Chain Monte Carlo analysis to put constraints on the effective cosmological constant $\Omega^0_{\rm eff}$. By imposing that the cosmological constant is the only component that possibly violates the ECs, we derive lower and upper bounds for its value. For instance, we obtain that $0.59 < \Omega^0_{\rm eff} < 0.91$ and $0.40 < \Omega^0_{\rm eff} < 0.93$ within, respectively, $1\sigma$ and $3\sigma$ confidence levels. In addition, about 30\% of the posterior distribution is incompatible with a cosmological constant, showing that this method can potentially rule it out as a mechanism for the accelerated expansion. We also study the consequence of these constraints for two particular formulations of the bimetric massive gravity. Namely, we consider the Visser's theory and the Hassan and Roses's massive gravity by choosing a background metric such that both theories mimic General Relativity with a cosmological constant. Using the $\Omega^0_{\rm eff}$ observational bounds along with the upper bounds on the graviton mass we obtain constraints on the parameter spaces of both theories.Comment: 11 pages, 4 figures, 1 tabl

Polpas branqueadas de misturas de madeiras da Amazônia.

bitstream/item/31959/1/CPATU-BP82.pd

Consórcio de Brachiaria ruziziensis com populações de Crotalaria ochroleuca.

JIPE 2013

Perfil clínico e andrológico de bodes Moxotó e Canindé infectados experimentalmente com lentivírus de pequenos ruminantes (LVPR).

Clinical and andrological profile of Canindé and Moxotó bucks experimentally infected with small ruminants lentivirus (LVPR). Abstract: The aim in this work was to evaluate the clinical, hematologic and andrologic characteristics of native bucks experimentally infected by CAEV. Ten native bucks from Canindé and Moxotó breeds were used, divided in a group experimentally infected and a group control non infected. The hematologic evaluation was accomplished monthly, clinical evaluation biweekly and andrologic evaluation weekly. Before the experimental infection, all the bucks presented normal at clinical and andrologic evaluation. The hematologic evaluation did not differ significantly between the experimental groups. The animals presented values below the normal for bucks for the hematocrit, hemoglobin and CHCM in some months of evaluation. The seminal volume was significantly superior in the infected animals before the infection and the sperm concentration superior only in the third month of evaluation. The caprine arthritis-encephalitis virus does not alter the clinical, hematologic and andrologic parameters from native bucks recently infected in the period that precedes the seroconversion.Trabalho apresentado no 6o. Congresso Norte Nordeste de Reprodução animal, 2012, Fortaleza

Soroprevalência da infecção por Brucella ovis em ovinos explorados na microrregião homogênea de Teresina, Piauí, Brasil.

[Brucella ovis infection seroprevalence in sheep exploited the homogeneous micro Teresina, Piaui, Brazil]. Abstract: Considering the importance of this disease and the lack of data on the state of Piauí, the aim of this study was to determine the sero-epidemiological situation of Brucella ovis infection in sheep from Teresina homogeneous microregion, Piauí. The study included a sampling universe of 282 sheep distributed in 24 herds, and the samples were collected by venipuncture of the jugular vein. Serology for detection of anti-B. ovis antibodies was performed by the method of agarose gel immunodiffusion (AGID). Of the 282 samples tested, there was 5.67% (16/282) positive to B. ovis infection by immunodiffusion in agarose gel test. Brucella ovis is present in sheep flocks in Teresina homogeneous microregion, necessitating thus the implementation of control measures to prevent the spread of this disease.Trabalho apresentado nos Anais do VII Congresso Norte Nordeste de Reprodução Anima (CONERA), Mossoró, maio, 2014