Solar Chameleons

We analyse the creation of chameleons deep inside the sun and their subsequent conversion to photons near the magnetised surface of the sun. We find that the spectrum of the regenerated photons lies in the soft X-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarisations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft X-ray energy range. Moreover, using the soft X-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling the chameleons emitted by the sun could lead to a regenerated photon flux in the CAST pipes, which could be within the reach of CAST with upgraded detector performance. Then, axion helioscopes have thus the potential to detect and identify particles candidates for the ubiquitous dark energy in the universe.Comment: 16 pages, 6 figures

Kinematics of Tycho-2 Red Giant Clump Stars

Based on the Ogorodnikov-Milne model, we analyze the proper motions of 95 633 red giant clump (RGC) stars from the Tycho-2 Catalogue. The following Oort constants have been found: A = 15.9+-0.2 km/s/kpc and B = -12.0+-0.2 km/s/kpc. Using 3632 RGC stars with known proper motions, radial velocities, and photometric distances, we show that, apart from the star centroid velocity components relative to the Sun, only the model parameters that describe the stellar motions in the XY plane differ significantly from zero. We have studied the contraction (a negative K-effect) of the system of RGC stars as a function of their heliocentric distance and elevation above the Galactic plane. For a sample of distant (500--1000 pc) RGC stars located near the Galactic plane (|Z|<200 pc) with an average distance of d=0.7 kpc, the contraction velocity is shown to be Kd= -3.5+-0.9 km/s; a noticeable vertex deviation, lxy = 9.1+-0.5 degrees, is also observed for them. For stars located well above the Galactic plane (|Z|>=200 pc), these effects are less pronounced, Kd = -1.7+-0.5 km/s and lxy = 4.9+-0.6 degrees. Using RGC stars, we have found a rotation around the Galactic X axis directed toward the Galactic center with an angular velocity of -2.5+-0.3 km/s/kpc, which we associate with the warp of the Galactic stellar-gaseous disk.Comment: 23 pages, 7 figures, 4 table

A caricature of a singular curvature flow in the plane

We study a singular parabolic equation of the total variation type in one dimension. The problem is a simplification of the singular curvature flow. We show existence and uniqueness of weak solutions. We also prove existence of weak solutions to the semi-discretization of the problem as well as convergence of the approximating sequences. The semi-discretization shows that facets must form. For a class of initial data we are able to study in details the facet formation and interactions and their asymptotic behavior. We notice that our qualitative results may be interpreted with the help of a special composition of multivalued operators

Interactions between magnetic nanoparticles and model lipid bilayers—Fourier transformed infrared spectroscopy (FTIR) studies of the molecular basis of nanotoxicity

The toxicity of nanoparticles (nanotoxicity) is often associated with their interruption of biological membranes. The effect of polymer-coated magnetic nanoparticles (with different Fe3O4 core sizes and different polymeric coatings) on a model biological membrane system of vesicles formed by dimyristoylphosphatidylcholine (DMPC) was studied. Selected magnetic nanoparticles with core sizes ranging from 3 to 13 nm (in diameter) were characterised by transmission electron microscopy. Samples with 10% DMPC and different nanoparticle concentrations were studied by attenuated total reflectance—Fourier transform infrared spectroscopy to establish the influence of nanoparticles on the phase behaviour of model phospholipid systems

Desenvolvimento e aceitação de barra de cereal sabor umbu (Spondias tuberosa).

Produto bastante consumido nos dias atuais, a barra de cereal é uma alternativa saudável e prática. Este trabalho teve como objetivo formular barra de cereais contendo umbu, de preparo simples e baixo custo, e avaliar a aceitação do produto pelos consumidores, afim de propor a possível elaboração por pequenas agroindústrias. Foram desenvolvidas três formulações contendo ingredientes em diferentes proporções. A amostra 1 foi composta por xarope de polpa de umbu com sacarose, aveia prensada, coco ralado, castanha de caju, flocos de arroz, uva passa e doce de umbu em corte. A amostra 2 continha xarope de polpa de umbu com glicose, aveia prensada, coco ralado, castanha de caju, flocos de arroz e uva passa; e a amostra 3 foi composta por xarope caramelizado de polpa de umbu com sacarose, aveia prensada, coco ralado, castanha de caju, flocos de arroz e uva passa. Foi realizado teste de aceitação das barrinhas com 50 consumidores que avaliaram o quanto gostaram do produto utilizando escala hedônica de nove pontos (1=desgostei x extremamente; 9=gostei extremamente), além do grau de intenção de compra (1=certamente não compraria; 5=certamente compraria). Para aceitação da aparência, cor e textura as três formulações obtiveram notas sem diferença estatística (p < 0.05) entre si, e acima de 7, equivalente a ?gostei moderadamente? na escala. Para aroma, sabor e impressão global, as amostras 1 e 3 destacaram -se da amostra 2, sendo que a amostra 3 obteve as maiores médias de aceitação. Com relação ao sabor, a amostra 3 obteve média 8, equivalente a ?gostei muito? na escala. Segundo o teste de intenção de compra, 60% dos consumidores responderam que ?certamente comprariam? a amostra 3 caso estivesse a venda. Através desse trabalho pode-se concluir que as formulações testadas apresentaram bons resultados de aceitação, e que a formulação com xarope caramelizado foi a preferida pelos consumidores