Modelling the spectral energy distribution of galaxies: introducing the artificial neural network

The spectral energy distribution (SED) of galaxies is a complex function of the star formation history and geometrical arrangement of stars and gas in galaxies. The computation of the radiative transfer of stellar radiation through the dust distribution is time-consuming. This aspect becomes unacceptable in particular when dealing with the predictions by semi-analytical galaxy formation models populating cosmological volumes, to be then compared with multi-wavelength surveys. Mainly for this aim, we have implemented an artificial neural network (ANN) algorithm into the spectro-photometric and radiative transfer code GRASIL in order to compute the SED of galaxies in a short computing time. This allows to avoid the adoption of empirical templates that may have nothing to do with the mock galaxies output by models. The ANN has been implemented to compute the dust emission spectrum (the bottleneck of the computation), and separately for the star-forming molecular clouds (MC) and the diffuse dust (due to their different properties and dependencies). We have defined the input neurons effectively determining their emission, which means this implementation has a general applicability and is not linked to a particular galaxy formation model. We have trained the net for the disc and spherical geometries, and tested its performance to reproduce the SED of disc and starburst galaxies, as well as for a semi-analytical model for spheroidal galaxies. We have checked that for this model both the SEDs and the galaxy counts in the Herschel bands obtained with the ANN approximation are almost superimposed to the same quantities obtained with the full GRASIL. We conclude that this method appears robust and advantageous, and will present the application to a more complex SAM in another paper

External validation of EORTC risk scores to predict recurrence after transurethral resection of brazilian patients with non -muscle invasive bladder cancer stages Ta and T1

Validate the EORTC risk tables in Brazilian patients with NMIBC. Methods: 205 patients were analyzed. The 6 parameters analyzed were: histologic grading, pathologic stage, size and number of tumors, previous recurrence rate and concomitant CIS. The time for first recurrence (TFR), risk score and probability of re\uadcurrence were calculated and compared to the probabilities obtained from EORTC risk tables. C-index was calculated and accuracy of EORTC tables was analyzed. Results: pTa was presented in 91 (44.4%) patients and pT1 in 114 (55.6%). Ninety-seven (47.3%) patients had solitary tumor, and 108 (52.7%) multiple tumors. One hundred and three (50.2%) patients had tumors smaller than 3 cm and 102 (40.8%) had bigger than 3 cm. Concomitant CIS was observed in 21 (10.2%) patients. Low grade was presented in 95 (46.3%) patients, and high grade in 110 (53.7%). Intravesical therapy was utilized in 105 (56.1%) patients. Recurrence was observed in 117 (57.1%) patients and the mean TFR was 14,2 \ub1 7,3 months. C-index was 0,72 for 1 year and 0,7 for 5 years. The recurrence risk was 28,8% in 1 year and 57,1% in 5 years, independently of the scoring risk. In our population, the EORTC risk tables overestimated the risk of recurrence in 1 year and underestimated in 5 years. Conclusion: The validation of the EORTC risk tables in Brazilian patients with NMIBC was satisfactory and should be stimulated to predict recurrence, although these may overestimated the risk of recurrence in 1 year and underestimated in 5 years

TeV-scale seesaw from a multi-Higgs model

We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no large flavor changing neutral currents, are satisfied since the extra doublet only has a Yukawa interaction with lepton doublets and right-handed neutrinos, and their masses are heavy of order a TeV-scale. Since active light neutrinos are Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure

Rice F-bZIP transcription factors regulate the zinc deficiency response

The F-bZIP transcription factors bZIP19 and bZIP23 are the central regulators of the zinc deficiency response in Arabidopsis, and phylogenetic analysis of F-bZIP homologs across land plants indicates that the regulatory mechanism of the zinc deficiency response may be conserved. Here, we identified the rice F-bZIP homologs and investigated their function. OsbZIP48 and OsbZIP50, but not OsbZIP49, complement the zinc deficiency-hypersensitive Arabidopsis bzip19bzip23 double mutant. Ectopic expression of OsbZIP50 in Arabidopsis significantly increases plant zinc accumulation under control zinc supply, suggesting an altered Zn sensing in OsbZIP50. In addition, we performed a phylogenetic analysis of F-bZIP homologs from representative monocot species that supports the branching of plant F-bZIPs into Group 1 and Group 2. Our results suggest that regulation of the zinc deficiency response in rice is conserved, with OsbZIP48 being a functional homolog of AtbZIP19 and AtbZIP23. A better understanding of the mechanisms behind the Zn deficiency response in rice and other important crops will contribute to develop plant-based strategies to address the problems of Zn deficiency in soils, crops, and cereal-based human diets.</p

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review