Carotenoids from Phaffia rhodozyma: Antioxidant activity and stability of extracts

The main goal of this work was to establish the stability and antioxidant activity of the extracts obtained through different techniques for recovering carotenoids from Phaffia rhodozyma NRRL-Y 17268. The best conditions for extracting carotenoids through cell rupture with dimethylsulfoxide (DMSO) were found to be a particle size of 0.125 mm submitted to freezing temperature (-18°C) for 48 h (272 μg/g). For DMSO extracts, freezing negatively affected the antioxidant activity by 2,2 '-azinobis (3-ethyl benzothiazoline-6-sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The carotenogenic extracts obtained by enzymatic disruption proved to be more promising in relation to its antioxidant activity.Key words: Microbial carotenoids, antioxidant properties, cell wall disruption

Decaying Dark Matter in the Supersymmetric Standard Model with Freeze-in and Seesaw mechanims

Inspired by the decaying dark matter (DM) which can explain cosmic ray anomalies naturally, we consider the supersymmetric Standard Model with three right-handed neutrinos (RHNs) and R-parity, and introduce a TeV-scale DM sector with two fields \phi_{1,2} and a $Z_3$ discrete symmetry. The DM sector only interacts with the RHNs via a very heavy field exchange and then we can explain the cosmic ray anomalies. With the second right-handed neutrino N_2 dominant seesaw mechanism at the low scale around 10^4 GeV, we show that \phi_{1,2} can obtain the vacuum expectation values around the TeV scale, and then the lightest state from \phi_{1,2} is the decay DM with lifetime around \sim 10^{26}s. In particular, the DM very long lifetime is related to the tiny neutrino masses, and the dominant DM decay channels to \mu and \tau are related to the approximate \mu-\tau symmetry. Furthermore, the correct DM relic density can be obtained via the freeze-in mechanism, the small-scale problem for power spectrum can be solved due to the decays of the R-parity odd meta-stable states in the DM sector, and the baryon asymmetry can be generated via the soft leptogensis.Comment: 24 pages,3 figure

The Interplay Between GUT and Flavour Symmetries in a Pati-Salam x S4 Model

Both Grand Unified symmetries and discrete flavour symmetries are appealing ways to describe apparent structures in the gauge and flavour sectors of the Standard Model. Both symmetries put constraints on the high energy behaviour of the theory. This can give rise to unexpected interplay when building models that possess both symmetries. We investigate on the possibility to combine a Pati-Salam model with the discrete flavour symmetry $S_4$ that gives rise to quark-lepton complementarity. Under appropriate assumptions at the GUT scale, the model reproduces fermion masses and mixings both in the quark and in the lepton sectors. We show that in particular the Higgs sector and the running Yukawa couplings are strongly affected by the combined constraints of the Grand Unified and family symmetries. This in turn reduces the phenomenologically viable parameter space, with high energy mass scales confined to a small region and some parameters in the neutrino sector slightly unnatural. In the allowed regions, we can reproduce the quark masses and the CKM matrix. In the lepton sector, we reproduce the charged lepton masses, including bottom-tau unification and the Georgi-Jarlskog relation as well as the two known angles of the PMNS matrix. The neutrino mass spectrum can present a normal or an inverse hierarchy, and only allowing the neutrino parameters to spread into a range of values between $\lambda^{-2}$ and $\lambda^2$, with $\lambda\simeq0.2$. Finally, our model suggests that the reactor mixing angle is close to its current experimental bound.Comment: 62 pages, 4 figures; references added, version accepted for publication in JHE

Size Evolution of Ordered SiGe Islands Grown by Surface Thermal Diffusion on Pit-Patterned Si(100) Surface

The ordered growth of self-assembled SiGe islands by surface thermal diffusion in ultra high vacuum from a lithographically etched Ge stripe on pit-patterned Si(100) surface has been experimentally investigated. The total surface coverage of Ge strongly depends on the distance from the source stripe, as quantitatively verified by Scanning Auger Microscopy. The size distribution of the islands as a function of the Ge coverage has been studied by coupling atomic force microscopy scans with Auger spectro-microscopy data. Our observations are consistent with a physical scenario where island positioning is essentially driven by energetic factors, which predominate with respect to the local kinetics of diffusion, and the growth evolution mainly depends on the local density of Ge atoms

Strong coupling, discrete symmetry and flavour

We show how two principles - strong coupling and discrete symmetry - can work together to generate the flavour structure of the Standard Model. We propose that in the UV the full theory has a discrete flavour symmetry, typically only associated with tribimaximal mixing in the neutrino sector. Hierarchies in the particle masses and mixing matrices then emerge from multiple strongly coupled sectors that break this symmetry. This allows for a realistic flavour structure, even in models built around an underlying grand unified theory. We use two different techniques to understand the strongly coupled physics: confinement in N=1 supersymmetry and the AdS/CFT correspondence. Both approaches yield equivalent results and can be represented in a clear, graphical way where the flavour symmetry is realised geometrically.Comment: 31 pages, 5 figures, updated references and figure

The view of teachers on bullying and implications for nursing

Objetivo: Compreender o bullying escolar, na perspectiva dos professores, e refletir sobre as possíveis ações da área da saúde em seu enfrentamento. Para tanto, tomaram- se por base as diretrizes do Programa Saúde na Escola, dos Ministérios da Saúde e da Educação. Método: Estudo de caso qualitativo, realizado com professores de uma escola pública de Minas Gerais. Foram utilizados grupos focais na coleta de dados e o material empírico foi decodificado a partir de técnica de análise temática de conteúdo, resultando em uma categoria analítica: concepções e experiências de professores diante do bullying. Resultados: Foram identificadas percepções pontuais sobre o fenômeno e utilização de recursos de intervenção pouco eficazes. No plano interpretativo, problematizaram-se as contribuições da saúde e da enfermagem no redimensionamento das intervenções e no processo de formação continuada dos professores. Conclusão: Os resultados apontam para a construção de práticas intersetoriais para o enfrentamento do bullying.To understand school bullying from the perspective of teachers and reflect about the possible actions of the health area when coping with it. The guidelines of the School Health Program of the Ministries of Health and Education were used to reach that purpose. Method: A qualitative study carried out with teachers of a public school in Minas Gerais. Focus groups were used to collect data and the empirical material was decoded from thematic analysis of content, resulting in an analytical category: conceptions and experiences of teachers on bullying. Results: Specific perceptions about the phenomenon and the use of ineffective intervention resources were identified. In the interpretive plan were problematized the health and nursing contributions with resizing the interventions and the continuing training process of teachers. Conclusion: The results point to the construction of intersectoral practices forcoping with bullying.Objetivo: Comprender el bullying escolar desde la perspectiva de los profesores, y reflexionar sobre las posibles acciones del área de salud en su enfrentamiento. Tomando como base los lineamientos del Programa de Salud Escolar, de los Ministerios de Salud y de Educación. Método: Estudio de caso cualitativo realizado con los profesores de una escuela pública en Minas Gerais. Para la recolección de datos se utilizaron grupos focales y el material empírico fue decodificado a partir de la técnica de análisis temático de contenido, dando lugar a una categoría analítica: concepciones y experiencias de los profesores sobre el acoso escolar. Resultados: Se identificaron percepciones específicas sobre el fenómeno y la utilización de recursos ineficaces de intervención. En el plano interpretativo, se problematizaron las contribuciones de la salud y de la enfermería en el redimensionamiento de las intervenciones y en el proceso de formación continua de los profesores. Conclusión: Los resultados apuntan a la construcción de prácticas intersectoriales para el enfrentamiento del bullying.CIEC - Centro de Investigação em Estudos da Criança, UM (UI 317 da FCT

Cascade Textures and SUSY SO(10) GUT

We give texture analyses of cascade hierarchical mass matrices in supersymmetric SO(10) grand unified theory. We embed cascade mass textures of the standard model fermion with right-handed neutrinos into the theory, which gives relations among the mass matrices of the fermions. The related phenomenologies, such as the lepton flavor violating processes and leptogenesis, are also investigated in addition to the PMNS mixing angles.Comment: 27 pages, 4 figures, comments and references added, final versio

Employment and sociodemographic characteristics: a study of increasing precarity in the health districts of Belo Horizonte, Brazil

<p>Abstract</p> <p>Background</p> <p>The fundamental importance of human resources for the development of health care systems is recognized the world over. Health districts, which constitute the middle level of the municipal health care system in the city of Belo Horizonte, Brazil, deal with demands from all parts of the system. This research seeks to provide the essential features required in order to understand the phenomenon of increase in precarity of employment in these health districts.</p> <p>Methods</p> <p>The legal and human resource management documents used by the Municipal Health Secretariat of the City of Belo Horizonte were adopted as the corpus for this research. In order to analyse the changes in employment (2002–2006), the data were collected from ArteRH, a computerized database dealing specifically with data related to human resources, which began operating in 2001. The workers were classified into permanent and non-permanent groups, and their contractual rights were described. Employment dynamics and changes were examined, concentrating on the incorporation of workers and on their social and employment rights during the period under study. The comparative data for the two groups obtained were presented in frequency distribution tables according to type of employment, sex, age group, level of education and wages from 2002 to 2006.</p> <p>Results</p> <p>There was a clear difference between the permanent worker and non-permanent worker groups as regards existing guaranteed employment rights and social security. The increase in the number of non-permanent workers in the workforce, the growing proportion of older workers among the permanently employed and the real wage reductions during the period from 2002 to 2006 are indicative of the process of growing precarity of employment in the group studied.</p> <p>Conclusion</p> <p>It is a plausible supposition that the demand for health reforms, along with the legal limits imposed on financial expenditure, gave rise to the new types of contract and the present employment situation in the health districts in Belo Horizonte.</p