The radial metallicity gradients in the Milky Way thick disk as fossil signatures of a primordial chemical distribution

In this letter we examine the evolution of the radial metallicity gradient induced by secular processes, in the disk of an $N$-body Milky Way-like galaxy. We assign a [Fe/H] value to each particle of the simulation according to an initial, cosmologically motivated, radial chemical distribution and let the disk dynamically evolve for 6 Gyr. This direct approach allows us to take into account only the effects of dynamical evolution and to gauge how and to what extent they affect the initial chemical conditions. The initial [Fe/H] distribution increases with R in the inner disk up to R ~ 10 kpc and decreases for larger R. We find that the initial chemical profile does not undergo major transformations after 6 Gyr of dynamical evolution. The final radial chemical gradients predicted by the model in the solar neighborhood are positive and of the same order of those recently observed in the Milky Way thick disk. We conclude that: 1) the spatial chemical imprint at the time of disk formation is not washed out by secular dynamical processes, and 2) the observed radial gradient may be the dynamical relic of a thick disk originated from a stellar population showing a positive chemical radial gradient in the inner regions.Comment: 10 pages, 5 figures, Accepted for publication on Astrophysical Journal Letter

Bacteriófagos líticos para salmonelas.

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Virulência de amostras de Mycoplasma synoviae isoladas no Brasil.

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Implementasi Konsep Timor Pada Perancangan Interior Restoran Timor Di Kota Kupang - Nusa Tenggara Timur

Local culture as a concept of interior design design is often considered outdated for modern society. In fact, local culture in Indonesia has variety of values and arts. One of the least exposed is the Timor culture originating from Kupang, East Nusa Tenggara. The culture of Timor can be applied to the interior design of the restaurant as one of the business areas with a high number of enthusiasts. This design offers the concept for visitors to enjoy entertainment and socialize while enjoying the food and drinks provided. The restaurant provides food and beverage service that offers an ethnic and artistic atmosphere. With this design, people's point of view of local culture will get better

Síndrome da hipertensão pulmonar: a ascite em frangos de corte.

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Contaminação por aflatoxinas em milho utilizado na alimentação de suínos.

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Sistemas de manejo de solo e de rotação de culturas: implicações na emissão de óxido nitroso do solo.

Orientador: Henrique Pereira dos Santos

The ILIUM forward modelling algorithm for multivariate parameter estimation and its application to derive stellar parameters from Gaia spectrophotometry

I introduce an algorithm for estimating parameters from multidimensional data based on forward modelling. In contrast to many machine learning approaches it avoids fitting an inverse model and the problems associated with this. The algorithm makes explicit use of the sensitivities of the data to the parameters, with the goal of better treating parameters which only have a weak impact on the data. The forward modelling approach provides uncertainty (full covariance) estimates in the predicted parameters as well as a goodness-of-fit for observations. I demonstrate the algorithm, ILIUM, with the estimation of stellar astrophysical parameters (APs) from simulations of the low resolution spectrophotometry to be obtained by Gaia. The AP accuracy is competitive with that obtained by a support vector machine. For example, for zero extinction stars covering a wide range of metallicity, surface gravity and temperature, ILIUM can estimate Teff to an accuracy of 0.3% at G=15 and to 4% for (lower signal-to-noise ratio) spectra at G=20. [Fe/H] and logg can be estimated to accuracies of 0.1-0.4dex for stars with G<=18.5. If extinction varies a priori over a wide range (Av=0-10mag), then Teff and Av can be estimated quite accurately (3-4% and 0.1-0.2mag respectively at G=15), but there is a strong and ubiquitous degeneracy in these parameters which limits our ability to estimate either accurately at faint magnitudes. Using the forward model we can map these degeneracies (in advance), and thus provide a complete probability distribution over solutions. (Abridged)Comment: MNRAS, in press. This revision corrects a few minor errors and typos. A better formatted version for A4 paper is available at http://www.mpia.de/home/calj/ilium.pd