Cosmology with interaction in the dark sector

Unless some unknown symmetry in Nature prevents or suppresses a non-minimal coupling in the dark sector, the dark energy field may interact with the pressureless component of dark matter. In this paper, we investigate some cosmological consequences of a general model of interacting dark matter-dark energy characterized by a dimensionless parameter $\epsilon$. We derive a coupled scalar field version for this general class of scenarios and carry out a joint statistical analysis involving SNe Ia data ({Legacy} and {Constitution} sets), measurements of baryon acoustic oscillation peak at $z = 0.20$ (2dFGRS) and $z = 0.35$ (SDSS), and measurements of the Hubble evolution $H(z)$. For the specific case of vacuum decay ($w = -1$), we find that, although physically forbidden, a transfer of energy from dark matter to dark energy is favored by the data.Comment: 5 pages, 5 figures, LaTe

Scalar field description of a parametric model of dark energy

We investigate theoretical and observational aspects of a time-dependent parameterization for the dark energy equation of state (EoS) $w(z)$, which is a well behaved function of the redshift $z$ over the entire cosmological evolution, i.e., $z \in [-1,\infty)$. By using a theoretical algorithm of constructing the quintessence potential directly from the effective EoS parameter, we derive and discuss the general features of the resulting potential for this $w(z)$ function. Since the parameterization here discussed allows us to divide the parametric plane in defined regions associated to distinct classes of dark energy models, we use the most recent observations from type Ia supernovae, baryon acoustic oscillation peak and Cosmic Microwave Background shift parameter to check which class is observationally prefered. We show that the largest portion of the confidence contours lies into the region corresponding to a possible crossing of the so-called phanton divide line at some point of the cosmic evolution.Comment: 5 pages, 2 figures, LaTe

Instruções para o cultivo da acerola.

bitstream/item/44461/1/CPATC-DOCUMENTOS-6-INSTRUCOES-PARA-O-CULTIVO-DA-ACEROLA-FL-13124.pd

Ocorrência de um Potyvirus associado ao mosaico da açucena-gigante.

Plants of spider lily (Crinum sp) showing mosaic symptoms were found in Londrina, Paraná. Electron microscopy examinations revealed flexuous rod shaped particles and lamellar inclusion bodies in the cell cytoplasm. RT-PCR products of 2 kb were amplified by a pair of genus specific primers suggesting the association of a potyvirus, being this the first time a virus infection in this host is reported in Brazil

Scalar field description of a parametric model of dark energy

We investigate theoretical and observational aspects of a time-dependent parameterization for the dark energy equation of state (EoS) $w(z)$, which is a well behaved function of the redshift $z$ over the entire cosmological evolution, i.e., $z \in [-1,\infty)$. By using a theoretical algorithm of constructing the quintessence potential directly from the effective EoS parameter, we derive and discuss the general features of the resulting potential for this $w(z)$ function. Since the parameterization here discussed allows us to divide the parametric plane in defined regions associated to distinct classes of dark energy models, we use the most recent observations from type Ia supernovae, baryon acoustic oscillation peak and Cosmic Microwave Background shift parameter to check which class is observationally prefered. We show that the largest portion of the confidence contours lies into the region corresponding to a possible crossing of the so-called phanton divide line at some point of the cosmic evolution.Comment: 5 pages, 2 figures, LaTe

ESTIMACIÓN DE MODELOS DE FUNCIÓN DE PRODUCCIÓN EN EL CULTIVO DE ALGODÓN PARA DIFERENTES ZONAS DE EXPERIMENTACIÓN.

- En el presente trabajo de investigación se realizó la estimación de función de producción de algodón en las diferentes zonas experimentales, con el objeto de  hallar el tipo de regresión estimada que mejor se ajuste a los datos proporcionados por el Proyecto de Investigación y Experimentación Algodonera – PIEA. Los ensayos fueron realizados en 9 zonas de la Región Oriental del Paraguay, utilizando dosis de 00 – 150 – 300 – 450 kg/ha de fertilizante NPK. Analizando los datos se pudo obtener la función de producción que mejor se adecua a la situación de cada localidad y mediante el análisis económico, se pudo determinar la cantidad óptima de fertilizante que maximizan los beneficios. Se determinó que la regresión del tipo cuadrática es la más representativa en 8 zonas de experimentación, mientras que en la zona de Horqueta fue significativa la regresión lineal, como así también en Guayaiby y Mbuyapey la regresión lineal presentó significancia. De todas las zonas experimentales, la zona de Ybycui fue la que presentó mejor rendimiento con 3.347,12 kg/ha de algodón con la utilización de 386,1 kg/ha de fertilizante. Con el análisis económico se constató que de las 9 zonas experimentales, en 4 de ellas se obtuvo el máximo beneficio económico sin la utilización de fertilizante

Formulation and Evaluation of Corn Pancakes Containing Bovine Plasma Protein and Tender Corn

Abstract: The purpose of this research was to fortify and evaluate some nutritional properties of a new product (corn pancakes), prepared with tender corn and bovine plasmatic protein. In doing so, two products were formulated. Both products were analyzed to determine their yield as well as their content of protein, fat, fiber, moisture, ash and essential amino acids. In addition to that, microbiological quality, degree of likeness, protein efficiency ratio and digestibility were also analyzed. All the results showed that the product containing bovine plasma had a higher yield, moisture and protein content (p<0.05). In almost all cases, the product containing bovine plasma met or exceeded the established ideal requirements of essential amino acids. The Protein Efficiency Ratio (PER), shows that the animals fed with the experimental diet, showed a weight gain of 2.64 g per each g of protein intake. Corn pancakes had acceptable sensory score 88.4% for taste and 95.3% for color. In conclusion, due to its acceptability and highly nutritious value, the product containing bovine plasma could be used as an alternative to help solve the nutritional problems the population is facing these days

Surface alignment of ferroelectric nematic liquid crystals

none8The success of nematic liquid crystals in displays and optical applications is due to the combination of their optical uniaxiality, fluidity, elasticity, responsiveness to electric fields and controllable coupling of the molecular orientation at the interface with solid surfaces. The discovery of a polar nematic phase opens new possibilities for liquid crystal-based applications, but also requires a new study of how this phase couples with surfaces. Here we explore the surface alignment of the ferroelectric nematic phase by testing different rubbed and unrubbed substrates that differ in coupling strength and anchoring orientation and find a variety of behaviors - in terms of nematic orientation, topological defects and electric field response - that are specific to the ferroelectric nematic phase and can be understood as a consequence of the polar symmetry breaking. In particular, we show that by using rubbed polymer surfaces it is easy to produce cells with a planar polar preferential alignment and that cell electrostatics (e.g.grounding the electrodes) has a remarkable effect on the overall homogeneity of the ferroelectric ordering.openCaimi F.; Nava G.; Barboza R.; Clark N.A.; Korblova E.; Walba D.M.; Bellini T.; Lucchetti L.Caimi, F.; Nava, G.; Barboza, R.; Clark, N. A.; Korblova, E.; Walba, D. M.; Bellini, T.; Lucchetti, L