Neutrino masses and mixing in A(4) models with three Higgs doublets

We study neutrino masses and mixing in the context of flavor models with A(4) symmetry, three scalar doublets in the triplet representation, and three lepton families. We show that there is no representation assignment that yields a dimension-5 mass operator consistent with experiment. We then consider a type-I seesaw with three heavy right-handed neutrinos, explaining in detail why it fails, and allowing us to show that agreement with the present neutrino oscillation data can be recovered with the inclusion of dimension-3 heavy neutrino mass terms that break softly the A(4) symmetry.

Evaluating the efficiency of a vegetal coagulant in the treatment of industrial effluents

The present work aims at evaluating the efficiency of an organic polymer from vegetal source used as coagulant for treating different types of industrial effluents. This coagulant (Flox-QT) is obtained from the Black Acacia (Acacia mearnsii). The effluents studied were produced in petrochemical, leather, cork stoppers, metalworking, olive oil, glue, paint (printing), textile and paper industries. The parameters analyzed in the effluents before and after treatment were selected according to the type of wastewater and included pH, conductivity, apparent colour, turbidity, total suspended solids (TSS), chemical oxygen demand (COD) and some metals. The coagulant proved to be efficient for almost all effluents tested. The best results were obtained for the paper industry wastewater, with 91% removal of chemical oxygen demand and 95% of total suspended solids removal. The estimated cost of this treatment would be only 0.24 Euro per cubic meter of treated effluent, only regarding the price of the coagulant and the required dosage. The use of this coagulant is also adequate for the valorisation of the sludge obtained, which in this case could be recycled for paper production.

Evolução da pesquisa epidemiológica em atividade física no Brasil: revisão sistemática

OBJETIVO: Descrever a evolução da pesquisa epidemiológica em atividade física no Brasil. MÉTODOS: Revisão sistemática da literatura, realizada em bases de dados eletrônicas (Medline/PubMed, Lilacs, Ovid, Science Direct, BioMed Central e High Wire), em periódicos nacionais não indexados, por busca específica por autores e contato com pesquisadores. A seleção dos artigos teve como critérios de inclusão: amostra representativa de alguma população definida; tamanho da amostra de pelo menos 500 indivíduos; coleta de dados realizada no Brasil; mensuração de atividade física e relato dos resultados com base nessa variável. RESULTADOS: Foram incluídos 42 estudos. O primeiro artigo foi publicado em 1990, observando-se tendência de aumento de publicações a partir de 2000. Foi detectada disparidade regional nas publicações, com concentração de estudos nas regiões Sudeste e Sul. A maioria dos estudos (93%) utilizou questionários como instrumentos de pesquisa, cujos conteúdos variaram, assim como as definições operacionais de sedentarismo, dificultando a comparação dos resultados. CONCLUSÕES: Embora a literatura em epidemiologia da atividade física venha crescendo quantitativamente no Brasil, limitações metodológicas dificultam a comparação entre os estudos, tornando a padronização de instrumentos e definições essenciais para o avanço científico da área.

Core group approach to identify college students at risk for sexually transmitted infections

OBJECTIVE: To analyze the core group for sexually transmitted infections (STI) among college students. METHODS: Cross-sectional study carried out in a convenience sample comprising 711 college students of the public university of Morelos, Mexico, between 2001 and 2003. Sociodemographic and sexual behavior information were collected using self-applied questionnaires. Herpes simplex 2 (HSV-2) infection was tested in the blood. The number of sexual partners in the last year and cocaine consumption were used as indicators to construct the dependent variable "level of STI risk" in three categories: low, medium and high risk (core group). A multinomial analysis was conducted to evaluate whether different sex behaviors were associated with the variable "level of STI risk". RESULTS: There was significant association between HSV-2 seroprevalence and the variable "level of STI risk": 13%, 5.6% and 3.8% were found in high (core group), medium and low categories, respectively. There were gender differences regarding the core group. Men started having sexual intercourse earlier, had more sex partners, higher alcohol and drug consumption, higher frequency of sex intercourse with sex workers, exchanging sex for money, occasional and concurrent partners compared to women. CONCLUSIONS: The study findings suggest existing contextual characteristics in the study population that affect their sex behavior. In Mexico, the cultural conception of sexuality is determined mainly by gender differences where men engage in higher risky sexual behavior than women.

Flavored asymmetries for type II seesaw leptogenesis

A novel contribution to the leptonic CP asymmetries in type II seesaw leptogenesis scenarios is obtained for the cases in which flavor effects are relevant for the dynamics of leptogenesis. In the so-called flavored leptogenesis regime, the interference between the tree-level amplitude of the scalar triplet decaying into two leptons and the one-loop wave function correction with leptons in the loop, leads to a new nonvanishing CP asymmetry contribution. The latter conserves total lepton number but violates lepton flavor. Cases in which this novel contribution may be dominant in the generation of the baryon asymmetry are briefly discussed.

Solution enthalpies of 1,4-dioxane: Study of solvent effects through quantitative structure-property relationships

Solution enthalpies of 1,4-dioxane have been obtained in 15 protic and aprotic solvents at 298.15 K. Breaking the overall process through the use of Solomonov's methodology the cavity term was calculated and interaction enthalpies (Delta H-int) were determined. Main factors involved in the interaction enthalpy have been identified and quantified using a QSPR approach based on the TAKA model equation. The relevant descriptors were found to be pi* and beta, which showed, respectively, exothermic and endothermic contributions. The magnitude of pi* coefficient points toward non-specific solute-solvent interactions playing a major role in the solution process. The positive value of the beta coefficient reflects the endothermic character of the solvents' hydrogen bond acceptor (HBA) basicity contribution, indicating that solvent molecules engaged in hydrogen bonding preferentially interact with each other rather than with 1,4-dioxane. (C) 2013 Elsevier B.V. All rights reserved.

Factors related to inadequate cervical cancer screening in two Brazilian state capitals

OBJECTIVE:To analyze factors associated with cervical cancer screening failure. METHODS:Population-based cross-sectional study with self-weighted two-stage cluster sampling conducted in the cities of Fortaleza (Northeastern Brazil) and Rio de Janeiro (Southeastern Brazil) in 2002. Subjects were women aged 25-59 years in the last three years prior to the study. Data were analyzed through Poisson regression using a hierarchical model. RESULTS: The proportion of women who did not undergo the Pap smear test in Fortaleza and Rio de Janeiro was 19.1% (95% CI: 16.1;22.1) and 16.5% (95% CI: 14.1;18.9), respectively. Higher prevalence ratios of cervical cancer screening failure in both cities were seen among women with low education and low per capita income, old age, unmarried, who never underwent mammography, clinical breast examination, and blood glucose and cholesterol level testing. Smokers also had lower screening rates compared to non-smoker women and this difference was only statistically significant in Rio de Janeiro. CONCLUSIONS:The study findings point to the need of intervention focusing particularly women in worse socioeconomic conditions and access to healthcare, old-aged and unmarried. Education activities must prioritize screening of asymptomatic women and early diagnosis for symptomatic women and access to adequate diagnostic methods and treatment should be provided.

Fatores considerados pela população como mais importantes para manutenção da saúde

OBJETIVO: Analisar os fatores que adultos e idosos consideram como mais importantes para manutenção da saúde. MÉTODOS: Estudo transversal realizado com 4.060 adultos e 4.003 idosos residentes em áreas de abrangência de 240 unidades básicas de saúde das regiões Sul e Nordeste, em 2005. Um cartão com figuras e frases referentes a sete fatores relacionados com o risco de doenças e agravos não transmissíveis era mostrado aos indivíduos para que indicassem o fator mais relevante para a saúde. Os fatores eram: manter uma alimentação saudável, fazer exercício físico regularmente, não tomar bebidas alcoólicas em excesso, realizar consultas médicas regularmente, não fumar, manter o peso ideal e controlar ou evitar o estresse. As análises foram ajustadas por regressão de Poisson com cálculo de razões de prevalência ajustadas, intervalos com 95% de confiança, e valores de significância usando os Testes de Wald para heterogeneidade e tendência linear. RESULTADOS: Os fatores mais freqüentemente indicados pelos adultos foram: alimentação saudável (33,8%), realizar exercício físico (21,4%) e não fumar (13,9%). Entre os idosos, os fatores mais relatados foram: alimentação saudável (36,7%), não fumar (17,7%) e consultar o médico regularmente (14,2%). Foram observadas diferenças entre os fatores citados conforme a região geográfica, variáveis demográficas, socioeconômicas e de saúde. CONCLUSÕES: A maioria de adultos e idosos, de ambas regiões, reconhece e indica a necessidade de manter uma alimentação saudável e de não fumar como medidas mais importantes para manutenção da saúde. Estratégias de educação em saúde devem considerar essas características dos indivíduos para estimular medidas específicas a serem adotadas para cada segmento populacional.

A light stop and electroweak baryogenesis

The possibility of creating baryon asymmetry at the electroweak phase transition in the minimal supersymmetric standard model is considered for the case when right-handed squarks are much lighter than left-handed ones. It is shown that the usual requirement upsilon(T-c)/T-c greater than or similar to 1 for baryogenesis can be satisfied in a range of the parameters of the model, consistent with present experimental bounds.

A new bridge between leptonic CP violation and leptogenesis

Flavour effects due to lepton interactions in the early Universe may have played an important role in the generation of the cosmological baryon asymmetry through leptogenesis. If the only source of high-energy CP violation comes from the left-handed leptonic sector, then it is possible to establish a bridge between flavoured leptogenesis and low-energy leptonic CP violation. We explore this connection taking into account our present knowledge about low-energy neutrino parameters and the matter-antimatter asymmetry observed in the Universe. In this framework, we find that leptogenesis favours a hierarchical light neutrino mass spectrum, while for quasi-degenerate and inverted hierarchical neutrino masses there is a very narrow allowed window. The absolute neutrino mass scale turns out to be m less than or similar to 0.1 eV. (c) 2007 Elsevier B.V. All rights reserved.

Enlarging the window for radiative leptogenesis

We investigate the scenario of resonant thermal leptogenesis, in which the leptonic asymmetries are generated through renormalization group corrections induced at the leptogenesis scale. In the framework of the standard model extended by three heavy Majorana neutrinos with masses M(1) = M(2) << M(3) at some high scale, we show that the mass splitting and CP-violating effects induced by renormalization group corrections can lead to values of the CP asymmetries large enough for a successful leptogenesis. In this scenario, the low-energy neutrino oscillation data can also be easily accommodated. The possibility of having an underlying symmetry behind the degeneracy in the right-handed neutrino mass spectrum is also discussed. (c) 2005 Elsevier B.V. All rights reserved.

Leptogenesis, CP violation and neutrino data: what can we learn?

A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in the framework of the standard model of electroweak interactions extended by the addition of three right-handed neutrinos, leading to the seesaw mechanism. We analyze the connection between GUT-motivated relations for the quark and lepton mass matrices and the possibility of obtaining a viable leptogenesis scenario. In particular, we analyze whether the constraints imposed by SO(10) GUTs can be compatible with all the available solar, atmospheric and reactor neutrino data and, simultaneously, be capable of producing the required baryon asymmetry via the leptogenesis mechanism. It is found that the Just-So(2) and SMA solar solutions lead to a viable leptogenesis even for the simplest SO(10) GUT, while the LMA, LOW and VO solar solutions would require a different hierarchy for the Dirac neutrino masses in order to generate the observed baryon asymmetry. Some implications on CP violation at low energies and on neutrinoless double beta decay are also considered. (C) 2002 Elsevier Science B.V. All rights reserved.

Radiatively induced Lorentz and CPT violation in Schwinger constant field approximation

The Schwinger proper-time method is an effective calculation method, explicitly gauge-invariant and nonperturbative. We make use of this method to investigate the radiatively induced Lorentz- and CPT-violating effects in quantum electrodynamics when an axial-vector interaction term is introduced in the fermionic sector. The induced Lorentz- and CPT-violating Chern-Simons term coincides with the one obtained using a covariant derivative expansion but differs from the result usually obtained in other regularization schemes. A possible ambiguity in the approach is also discussed. (C) 2001 Published by Elsevier Science B.V.

Removing ambiguities in the neutrino mass matrix

We suggest that the weak-basis independent condition det(M-nu) = 0 for the effective neutrino mass matrix can be used in order to remove the ambiguities in the reconstruction of the neutrino mass matrix from input data available from present and future feasible experiments. In this framework, we study the full reconstruction of M-nu with special emphasis on the correlation between the Majorana CP-violating phase and the various mixing angles. The impact of the recent KamLAND results on the effective neutrino mass parameter is also briefly discussed. (C) 2003 Elsevier Science B.V. All rights reserved.

Texture zeros and weak basis transformations

We investigate the physical meaning of some of the "texture zeros" which appear in most of the Ansatze on quark masses and mixings. It is shown that starting from arbitrary quark mass matrices and making a suitable weak basis transformation one can obtain some of these sets of zeros which therefore have no physical content. We then analyse the physical implications of a four-texture zero Ansatz which is in agreement with all present experimental data. (C) 2000 Elsevier Science B.V. AU rights reserved.