Exceptional Flux Compactifications

We consider type II (non-)geometric flux backgrounds in the absence of brane sources, and construct their explicit embedding into maximal gauged D=4 supergravity. This enables one to investigate the critical points, mass spectra and gauge groups of such backgrounds. We focus on a class of type IIA geometric vacua and find a novel, non-supersymmetric and stable AdS vacuum in maximal supergravity with a non-semisimple gauge group. Our construction relies on a non-trivial mapping between SL(2) x SO(6,6) fluxes, SU(8) mass spectra and gaugings of E7(7) subgroups.Comment: 51 pages, 2 figures and 4 tables. v3: change of SO(6,6) spinorial conventions, published versio

Infant mortality: comparison between two birth cohorts from Southeast and Northeast, Brazil

OBJECTIVE: To obtain population estimates and profile risk factors for infant mortality in two birth cohorts and compare them among cities of different regions in Brazil. METHODS: In Ribeirão Preto, southeast Brazil, infant mortality was determined in a third of hospital live births (2,846 singleton deliveries) in 1994. In São Luís, northeast Brazil, data were obtained using systematic sampling of births stratified by maternity unit (2,443 singleton deliveries) in 1997-1998. Mothers answered standardized questionnaires shortly after delivery and information on infant deaths was retrieved from hospitals, registries and the States Health Secretarys' Office. The relative risk (RR) was estimated by Poisson regression. RESULTS: In São Luís, the infant mortality rate was 26.6/1,000 live births, the neonatal mortality rate was 18.4/1,000 and the post-neonatal mortality rate was 8.2/1,000, all higher than those observed in Ribeirão Preto (16.9, 10.9 and 6.0 per 1,000, respectively). Adjusted analysis revealed that previous stillbirths (RR=3.67 vs 4.13) and maternal ageOBJETIVO: Obter estimativas populacionais e fatores de risco de mortalidade infantil em coortes de nascimentos e comparar esses fatores entre cidades de diferentes regiões do País. MÉTODOS: Em Ribeirão Preto, SP, a mortalidade infantil foi avaliada em 1/3 dos nascidos vivos hospitalares (2.846 partos únicos) em 1994. Em São Luís, MA, foi feita amostragem sistemática de partos estratificada por maternidade (2.443 partos únicos) em 1997/98. As mães responderam a questionários padronizados logo após o parto e as informações sobre os óbitos foram coletadas nos hospitais, nos cartórios e nas secretarias estaduais de saúde. Risco relativo (RR) e intervalo de confiança de 95% foram estimados pela regressão de Poisson. RESULTADOS: O coeficiente de mortalidade infantil (CMI) em São Luís foi 26,6/1.000 nascidos vivos, o coeficiente de mortalidade neonata (CMN)l 18,4/1.000 e o coeficiente de mortalidade pós-neonatal (CMPN) 8,2/1.000, valores superiores aos de Ribeirão Preto, com CMI 16,9/1.000, CMN 10,9/1.000,CMPN 6,0/1.000. Na análise ajustada, nas duas cidades, natimorto prévio (RR=3,67 vs 4,13) e idade matern

Fatores de risco associados aos problemas dos leitões no período pós-desmame.

Porque conhecer os fatores de risco?; Estudos desenvolvidos na Embrapa Suínos e Aves; Como usar esta tecnologia?bitstream/item/68657/1/DMeu-DiscoCNPSA-COM.-TEC.-226-98CNPSA-COM.-TEC.-226-98.pd

Extra dimensions in CERN LHC via mini-black holes: effective Kerr-Newman brane-world effects

We solve Einstein equations on the brane to derive the exact form of the braneworld-corrected perturbations in Kerr-Newman singularities, using Randall-Sundrum and Arkani-Hamed-Dimopoulos-Dvali (ADD) models. It is a consequence of such models the possibility that Kerr-Newman mini-black holes can be produced in LHC. We use this approach to derive a normalized correction for the Schwarzschild Myers-Perry radius of a static $(4+n)$-dimensional mini-black hole, using more realistic approaches arising from Kerr-Newman mini-black hole analysis. Besides, we prove that there are four Kerr-Newman black hole horizons in braneworld scenario we use, although only the outer horizon is relevant in the physical measurable processes. Parton cross sections in LHC and Hawking temperature are also investigated as functions of Planck mass (in the LHC range 1-10 TeV), mini-black hole mass and the number of large extra dimensions in braneworld large extra-dimensional scenarios. In this case a more realistic brane effect-corrected formalism can achieve more precisely the effective extra-dimensional Planck mass and the number of large extra dimensions -- in Arkani-Hamed-Dimopoulos-Dvali model -- or the size of the warped extra dimension -- in Randall-Sundrum formalism.Comment: 11 pages, 23 figures, citations update

Nanoemulsions of β-carotene using a high-energy emulsification-evaporation technique

Nanoemulsions of β-carotene were prepared using a high-energy emulsification-evaporation technique based on a 23 level factorial design. Results show that it is possible to obtain dispersions at a nanoscale range. Process parameters such as time and shear rate of homogenization affected significantly particle size distribution in terms of volume-weighted mean diameter and surface-weighted mean diameter. The obtained nanoemulsions presented a volume-surface diameter ranging from 9 to 280 nm immediately after the production of particles, displaying in all cases a monomodal size distribution. Those nanoemulsions showed a good physical stability during 21 days storage. The stability was evaluated by the maintenance of size distribution. However, β-carotene retention inside the micelles and color were affected by storage. Processing conditions also influenced storage stability.Fundação para a Ciência e a Tecnologia (FCT)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brasil)Conselho Nacional de Ciência e Tecnologia (CNPq, Brasil

Chemical characterization and antioxidant activity of sulfated polysaccharide from the red seaweed Gracilaria birdiae

Hydrocolloids from seaweeds have interesting functional properties, such as antioxidant activity and gelling ability. A polysaccharide was isolated by aqueous extraction at 90 C from the red seaweed Gracilaria birdiae (Gb), with a yield of 27.2% of the seaweed dry weight. The sulfate content of the polysaccharide was 8.4% and the main sugars present were galactose (65.4 mol%), 3,6-anhydrogalactose (25.1 mol%) and 6-O-methylgalactose (9.2 mol%). Gel permeation chromatography showed that Gb polysaccharide is a heterogeneous system, with molar mass at the main peak of 3.7 105 g mol1 and a shoulder of 2.6 106 g mol1. The sulfated polysaccharide of Gb characterized by FTIR exhibits the characteristic bands of agarocolloids (at 1375 and 770 cm1).The rheological behavior of Gb sulfated polysaccharide exhibits a gel-like behavior close to the one observed in commercial agar. The antioxidant properties of Gb sulfated polysaccharide were evaluated by measuring DPPH freeradical scavenging effect, showing that this polysaccharide has a moderate effect in inhibiting the formation of those radicals.The author B. W. S. Souza was recipient of a fellowship from the Coordenaco de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil). The authors M. A. Cerqueira, J.T. Martins and A. C. Pinheiro were recipient of fellowships from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) through grants SFRH/BD/23897/2005, SFRH/BD/32566/2006 and SFRH/BD/48120/2008, respectively. The authors thank the NGO Terramar for donating the algae. Thanks are also due to the financial support of FCT to the Research Unit 62/94-QOPNA

Could the variation in quasar luminosity, due to extra dimension 3-brane in RS model, be measurable?

We propose an alternative theoretical approach showing how the existence of an extra dimension in RS model can estimate the correction in the Schwarzschild radius of black holes, and consequently its measurability in terms of the variation of quasar luminosity, which can be caused by a imprint of an extra dimension endowing the geometry of a brane-world scenario in an AdS_5 bulk. This paper is intended to investigate the variation of luminosity due to accretion of gas in black holes (BHs) in the center of quasars, besides also investigating the variation of luminosity in supermassive BHs by brane-world effects, using RS model.Comment: Revtex4, 7 Pages, 6 Figures, v2 has minor change

He II λ\lambda4686 emission from the massive binary system in η\eta Car: constraints to the orbital elements and the nature of the periodic minima

{\eta} Carinae is an extremely massive binary system in which rapid spectrum variations occur near periastron. Most notably, near periastron the He II $\lambda 4686$ line increases rapidly in strength, drops to a minimum value, then increases briefly before fading away. To understand this behavior, we conducted an intense spectroscopic monitoring of the He II $\lambda 4686$ emission line across the 2014.6 periastron passage using ground- and space-based telescopes. Comparison with previous data confirmed the overall repeatability of EW(He II $\lambda 4686$), the line radial velocities, and the timing of the minimum, though the strongest peak was systematically larger in 2014 than in 2009 by 26%. The EW(He II $\lambda 4686$) variations, combined with other measurements, yield an orbital period $2022.7\pm0.3$ d. The observed variability of the EW(He II $\lambda 4686$) was reproduced by a model in which the line flux primarily arises at the apex of the wind-wind collision and scales inversely with the square of the stellar separation, if we account for the excess emission as the companion star plunges into the hot inner layers of the primary's atmosphere, and including absorption from the disturbed primary wind between the source and the observer. This model constrains the orbital inclination to $135^\circ$-$153^\circ$, and the longitude of periastron to $234^\circ$-$252^\circ$. It also suggests that periastron passage occurred on $T_0 = 2456874.4\pm1.3$ d. Our model also reproduced EW(He II $\lambda 4686$) variations from a polar view of the primary star as determined from the observed He II $\lambda 4686$ emission scattered off the Homunculus nebula.Comment: The article contains 23 pages and 17 figures. It has been accepted for publication in Ap

Anti-de Sitter curvature radius constrained by quasars in brane-world scenarios

This paper is intended to investigate the luminosity due to accretion of gas in supermassive black holes (SMBHs) in the center of quasars, using a brane-world scenario naturally endowed with extra dimensions, whereon theories formulated introduce corrections in the field equations at high energies. SMBHs possess the necessary highly energetic environment for the introduction of these corrections, which are shown to produce small deviations in all SMBH properties and, consequentely, corrections in the accretion theory that supports quasars radiative processes. The radiative flux observed from quasars indicates these deviations, from which the magnitude of the AdS$_5$ bulk curvature radius, and consequently the extra dimension compactification radius is estimated.Comment: 11 pages, RevTeX, Eq.(2) and (3) expanded, and comments thereon update