Emissão de etileno e de CO2 em mamão 'Sunrise Solo' e 'Golden'.

Frutos de mamoeiro ?Sunsire Solo? e ?Golden? foram armazenados a 10°C e a 25°C e monitorados diariamente quanto às emissões de CO2 e de C2H4, observando-se a evolução do índice de cor de casca. A não-alteração do índice de cor de casca, ao longo dos 20 dias de conservação a 10°C, refletiu a influência da refrigeração na retenção do metabolismo dos mamões. Houve dois incrementos da respiração e da emissão de etileno, no quarto dia e entre o oitavo e o nono dia, nos frutos armazenados a 25° C. A temperatura de 10° C deteve a respiração climatérica do mamão e a emissão de etileno, comprovando que o seu metabolismo se reduz, permitindo que os frutos apresentem aspecto imaturo após 20 dias de armazenamento.Emission of ethilene and CO2 in 'Sunrise Solo' and 'Golden' papaya

Evolução dos pigmentos durante o amadurecimento de mamão 'sunrise solo' e 'golden'.

O objetivo deste estudo foi explicar as diferenças na coloração da polpa e da casca entre os frutos dos mamoeiros 'Sunrise Solo' e 'Golden', e desenvolver escalas de maturação visual. Os frutos foram colhidos em sete estádios de maturação, baseando-se no percentual de coloração amarela na casca, em pomar comercial localizado em Linhares-ES. O mamão 'Golden' mostrou-se difícil de classificar por meio de escala visual, devido a sua coloração mais clara. O mamão 'Sunrise Solo' possui teores mais elevados de clorofila total, a e b, e reduzido teor de carotenóides totais, no primeiro estádio e em outros dois estádios (4° e 6° estádios de maturação). A mudança de cor foi mais evidente nesta cultivar. A relação entre clorofilas totais e carotenóides totais foi superior na cultivar Sunrise Solo até o sexto estádio. Por isso, recomenda-se cuidado no manuseio pós-colheita do mutante Golden, principalmente quanto ao ponto de colheita, por causa da dificuldade de distinção entre os estádios de maturação.Pigments evolution during ripening of papaya cultivar sunrise solo and the mutant golden

New OB star candidates in the Carina Arm around Westerlund 2 from VPHAS+

Date of Acceptance: 10/04/2015O and early B stars are at the apex of galactic ecology, but in the Milky Way, only a minority of them may yet have been identified. We present the results of a pilot study to select and parametrise OB star candidates in the Southern Galactic plane, down to a limiting magnitude of $g=20$. A 2 square-degree field capturing the Carina Arm around the young massive star cluster, Westerlund 2, is examined. The confirmed OB stars in this cluster are used to validate our identification method, based on selection from the $(u-g, g-r)$ diagram for the region. Our Markov Chain Monte Carlo fitting method combines VPHAS+ $u, g, r, i$ with published $J, H, K$ photometry in order to derive posterior probability distributions of the stellar parameters $\log(\rm T_{\rm eff})$ and distance modulus, together with the reddening parameters $A_0$ and $R_V$. The stellar parameters are sufficient to confirm OB status while the reddening parameters are determined to a precision of $\sigma(A_0)\sim0.09$ and $\sigma(R_V)\sim0.08$. There are 489 objects that fit well as new OB candidates, earlier than $\sim$B2. This total includes 74 probable massive O stars, 5 likely blue supergiants and 32 reddened subdwarfs. This increases the number of previously known and candidate OB stars in the region by nearly a factor of 10. Most of the new objects are likely to be at distances between 3 and 6 kpc. We have confirmed the results of previous studies that, at these longer distances, these sight lines require non-standard reddening laws with $3.5R_VPeer reviewe

Determining the Physical Properties of the B Stars II. Calibration of Synthetic Photometry

We present a new calibration of optical (UBV, Stromgren, uvby-beta, and Geneva) and near IR (Johnson RIJHK and 2MASS) photometry for B and early A stars derived from Kurucz (1991) Atlas model atmospheres. Our sample of stars consists of 45 normal, nearby B and early A stars which have high quality, low resolution IUE spectra and accurate Hipparcos parallaxes. The calibration is unique because it relies only on the UV spectral energy distributions, the absolute flux calibration of the V filter and the Hipparcos distances to determine the appropriate model atmospheres for the program stars. These models are then used to calibrate the synthetic photometry. We compare our results with previous, well accepted results and provide a thorough discussion of the random errors and systematic effects affecting the calibration. In particular, we demonstrate the influence of vsini on surface gravities derived from fitting model atmospheres. Finally, we discuss some of our intended applications of this new calibration.Comment: 56 pages, 11 Figures, electronic tables not included. To appear in AJ, March 200

Star Formation Histories of the LEGUS Dwarf Galaxies (I): recent History of NGC1705, NGC4449 and Holmberg II

We use HST observations from the Legacy Extragalactic UV Survey to reconstruct the recent star formation histories (SFHs) of three actively star-forming dwarf galaxies, NGC4449, Holmberg II and NGC1705, from their UV color-magnitude diagrams (CMDs). We apply a CMD fitting technique using two independent sets of stellar isochrones, PARSEC-COLIBRI and MIST, to assess the uncertainties related to stellar evolution modelling. Irrespective of the adopted stellar models, all the three dwarfs are found to have had almost constant star formation rates (SFRs) in the last 100-200 Myr, with modest enhancements (a factor of $\sim$2) above the 100 Myr-averaged-SFR. Significant differences among the three dwarfs are found in the overall SFR, the timing of the most recent peak and the SFR$/$area. The Initial Mass Function (IMF) of NGC1705 and Holmberg II is consistent with a Salpeter slope down to $\approx$ 5 M$_{\odot}$, whereas it is slightly flatter, s$=-2.0$, in NGC4449. The SFHs derived with the two different sets of stellar models are consistent with each other, except for some quantitative details, attributable to their input assumptions. They also share the drawback that all synthetic diagrams predict a clear separation in color between upper main sequence and helium burning stars, which is not apparent in the data. Since differential reddening, significant in NGC4449, or unresolved binaries don't appear to be sufficient to fill the gap, we suggest this calls for a revision of both sets of stellar evolutionary tracks.Comment: 22 pages, 17 figures, accepted for publication on Ap

Spitzer and JCMT Observations of the Active Galactic Nucleus in the Sombrero Galaxy (NGC 4594)

We present Spitzer 3.6-160 micron images, Spitzer mid-infrared spectra, and JCMT SCUBA 850 micron images of the Sombrero Galaxy (NGC 4594), an Sa galaxy with a 10^9 M_solar low luminosity active galactic nucleus (AGN). The brightest infrared sources in the galaxy are the nucleus and the dust ring. The spectral energy distribution of the AGN demonstrates that, while the environment around the AGN is a prominent source of mid-infrared emission, it is a relatively weak source of far-infrared emission, as had been inferred for AGN in previous research. The weak nuclear 160 micron emission and the negligible polycyclic aromatic hydrocarbon emission from the nucleus also implies that the nucleus is a site of only weak star formation activity and the nucleus contains relatively little cool interstellar gas needed to fuel such activity. We propose that this galaxy may be representative of a subset of low ionization nuclear emission region galaxies that are in a quiescent AGN phase because of the lack of gas needed to fuel circumnuclear star formation and Seyfert-like AGN activity. Surprisingly, the AGN is the predominant source of 850 micron emission. We examine the possible emission mechanisms that could give rise to the 850 micron emission and find that neither thermal dust emission, CO line emission, bremsstrahlung emission, nor the synchrotron emission observed at radio wavelengths can adequately explain the measured 850 micron flux density by themselves. The remaining possibilities for the source of the 850 micron emission include a combination of known emission mechanisms, synchrotron emission that is self-absorbed at wavelengths longer than 850 microns, or unidentified spectral lines in the 850 micron band.Comment: Accepted to ApJ, 200

The Herschel Reference Survey: Dust in Early-Type Galaxies and Across the Hubble Sequence

We present Herschel observations of 62 Early-Type Galaxies (ETGs), including 39 galaxies morphologically classified as S0+S0a and 23 galaxies classified as ellipticals using SPIRE at 250, 350 and 500 microns (and PACS 100 and 160 microns for 19 sources) as part of the volume-limited Herschel Reference Survey. We detect dust emission in 24% of the ellipticals and 62% of the S0s. The mean temperature of the dust is 23.9+/-0.8 K, warmer than that found for late-type galaxies in the Virgo Cluster. Including the non-detections, the mean dust mass is log(Mdust) = 5.9+/-0.1 and 5.2+/-0.1 Msun for the S0s and elliptical galaxies respectively. The mean dust-to-stellar mass is log(Mdust/Mstar) = -4.4+/-0.1 (S0s) and -5.8+/-0.1 (ellipticals). Virtually all the galaxies lie close to the red sequence yet the large number of detections of cool dust, the gas-to-dust ratios and the ratios of far-infrared to radio emission all suggest that many ETGs contain a cool interstellar medium similar to that in late-type galaxies. The mean dust-to-stellar mass ratio for S0s is approximatly a factor of ten less than for early-type spirals and the sizes of the dust sources in the S0s are also much smaller. We show that the difference cannot be explained by either the different bulge-to-disk ratios or environmental effects such as ram-pressure stripping. The wide range in the dust-to-stellar mass ratio for ETGs and the lack of a correlation between dust mass and optical luminosity suggest that much of the dust in the ETGs detected by Herschel has been acquired as the result of gravitational interactions; these interactions are unlikely to have had a major effect on the stellar masses of the ETGs. The Herschel observations tentatively suggest that in the most massive ETGs, the mass of the interstellar medium is unconnected to the evolution of the stellar populations.Comment: 28 Pages, 12 Figures. Submitted to ApJ December 2011; accepted January 201

Spin physics with antiprotons

New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to cross-sections in which the parton distribution functions (PDF) only appear, without any contribution from fragmentation functions; such processes are not affected by the chiral suppression of the transversity function $h_1(x)$. Spin asymmetries in hyperon production and Single Spin Asymmetries are discussed as well, together with further items like electric and magnetic nucleonic form factors and open charm production. Counting rates estimations are provided for each physical case. The sketch of a possible experimental apparatus is proposed.Comment: Presented for the proceedings of ASI "Spin and Symmetry", Prague, July 5-10, 2004, to be published in Czech. J. Phys. 55 (2005

STREGA: STRucture and Evolution of the GAlaxy - I : Survey overview and first results

STREGA (STRucture and Evolution of the GAlaxy) is a guaranteed time survey being performed at the VST (the ESO Very Large Telescope Survey Telescope) to map about 150 square degrees in the Galactic halo, in order to constrain the mechanisms of galactic formation and evolution. The survey is built as a 5 yr project, organized in two parts: a core programme to explore the surrounding regions of selected stellar systems and a second complementary part to map the southern portion of the Fornax orbit and extend the observations of the core programme. The adopted stellar tracers are mainly variable stars (RR Lyraes and long-period variables) and main-sequence turn-off stars for which observations in the g, r, i bands are obtained. We present an overview of the survey and some preliminary results for three observing runs that have been completed. For the region centred on ω Cen (37 deg^2), covering about three tidal radii, we also discuss the detected stellar density radial profile and angular distribution, leading to the identification of extratidal cluster stars. We also conclude that the cluster tidal radius is about 1.2 deg, in agreement with values in the literature based on the Wilson model.Peer reviewedFinal Accepted Versio