638 research outputs found
Molecular Gas, Dust and Star Formation in Galaxies: II. Dust properties and scalings in \sim\ 1600 nearby galaxies
We aim to characterize the relationship between dust properties. We also aim
to provide equations to estimate accurate dust properties from limited
observational datasets.
We assemble a sample of 1,630 nearby (z<0.1) galaxies-over a large range of
Mstar, SFR - with multi-wavelength observations available from wise, iras,
planck and/or SCUBA. The characterization of dust emission comes from SED
fitting using Draine & Li dust models, which we parametrize using two
components (warm and cold ). The subsample of these galaxies with global
measurements of CO and/or HI are used to explore the molecular and/or atomic
gas content of the galaxies.
The total Lir, Mdust and dust temperature of the cold component (Tc) form a
plane that we refer to as the dust plane. A galaxy's sSFR drives its position
on the dust plane: starburst galaxies show higher Lir, Mdust and Tc compared to
Main Sequence and passive galaxies. Starburst galaxies also show higher
specific Mdust (Mdust/Mstar) and specific Mgas (Mgas/Mstar). The Mdust is more
closely correlated with the total Mgas (atomic plus molecular) than with the
individual components. Our multi wavelength data allows us to define several
equations to estimate Lir, Mdust and Tc from one or two monochromatic
luminosities in the infrared and/or sub-millimeter.
We estimate the dust mass and infrared luminosity from a single monochromatic
luminosity within the R-J tail of the dust emission, with errors of 0.12 and
0.20dex, respectively. These errors are reduced to 0.05 and 0.10 dex,
respectively, if the Tc is used. The Mdust is correlated with the total Mism
(Mism \propto Mdust^0.7). For galaxies with Mstar 8.5<log(Mstar/Msun) < 11.9,
the conversion factor \alpha_850mum shows a large scatter (rms=0.29dex). The SF
mode of a galaxy shows a correlation with both the Mgass and Mdust: high
Mdust/Mstar galaxies are gas-rich and show the highest SFRs.Comment: 24 pages, 28 figures, 6 tables, Accepted for publication in A&
Indicadores ecotoxicológicos para águas de consumo humano.
Testes de toxicidade utilizando organismos vivos, são de alta vantagem em termos de custo e benefício. Mostram com rapidez a qualidade das amostras testadas quanto a toxicidade. Utiliza-se organismos padronizados, de vários níveis tróficos, os quais respondem de maneira diversa aos diversos componentes das amostras ambientais. A qualidade de águas tratadas por ETAs das cidades de Limeira e Piracicaba, SP, foram avaliadas quanto a toxicidade para o microcrustáceo Daphnia magna, celenterado Hydra attenuata, alga Pseudokirchneriella subcapitata e a bactéria Vibrio fischeri . As Daphnias e as algas mostraram se altamente sensíveis a cloração, as Hydras e Vibrio mostraram-se resistentes sendo possível ser realizados testes com águas tratadas e cloradas. O tiossulfato de sódio foi utilizado para precipitar o cloro das amostras cloradas, entretanto precipitou também outras substâncias, diminuindo a toxicidade das águas brutas, sem cloro. Análises de resíduos mostrou a presença de herbicidas e trihalometanos nas amostras de água tratada do rio Corumbataí. O crescimento da alga P.subcapitata foi inibido em concentrações de atrazina de 7 a 10 microgramas L-1, mas não de 3 a 3,7 microgramas g L-1 . Os testes toxicológicos são importantes ferramentas para indicar presença de compostos tóxicos em amostras de água e podem mostrar a qualidade das águas tratadas
A protocol for large scale genomic DNA isolation for cacao genetics analysis
Advances in DNA technology, such as marker assisted selection, detection of quantitative trait loci and genomic selection also require the isolation of DNA from a large number of samples and the preservation of tissue samples for future use in cacao genome studies. The present study proposes a method for the preservation of sample tissues for DNA extraction and for manual extraction of large number of samples using spheres. The integrity and concentration of the DNA by these methods were assessed and compared with conventional method using mortar. The best parameters in order to obtain a fine powder using spheres was the use of 4 lyophilized leaf disks (50 mg), a single steel ball of 6 mm in diameter, followed by 30 s of manual maceration. The quantity of DNA obtained was four times higher than the conventional method. The purity of the DNA obtained was satisfactory and proved to be amplifiable by PCR using SSR primers. The present approach is a reliable, rapid, simple and consistent DNA isolation method for cacao, compared to the conventional methods. The protocol greatly increases the efficiency of extraction and suggests an inexpensive and practical way of DNA isolation of cacao for large scale.Keywords: DNA extraction, cacao, spheres, lyophilized
Micronutrient and functional compounds biofortification of maize grains.
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Previous issue date: 2014-02-26201
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