Stellar formation rates in galaxies using Machine Learning models

Global Stellar Formation Rates or SFRs are crucial to constrain theories of galaxy formation and evolution. SFR's are usually estimated via spectroscopic observations which require too much previous telescope time and therefore cannot match the needs of modern precision cosmology. We therefore propose a novel method to estimate SFRs for large samples of galaxies using a variety of supervised ML models.Comment: ESANN 2018 - Proceedings, ISBN-13 978287587048

Highly luminescent perovskite–aluminum oxide composites

In this communication we report on the preparation of CH3NH3PbBr3 perovskite/Al2O3 nanoparticle composites in a thin film configuration and demonstrate their high photoluminescence quantum yield. The composite material is solution-processed at low temperature, using stable alumina nanoparticle dispersions. There is a large influence of the alumina nanoparticle concentration on the perovskite morphology and on its photoluminescence

Perovskite solar cells prepared by flash evaporation

A simple vacuum deposition method for the preparation of high quality hybrid organic-inorganic methylammonium lead iodide perovskite thin films is reported. When sandwiched in between organic charge transporting layers, such films lead to solar cells with a power conversion efficiency of 12.2%

When Merit Breeds Luck (or Not): An Experimental Study on Distributive Justice

We experimentally investigate subjects’ preferences for redistribution depending on i) their personal stake in the outcome (either absent or not), ii) the effect of luck in strengthening or weakening the income inequality as derived from merit, and iii) whether individuals are informed about their relative wealth position in the society or not. We find that self-interest is the main driver of subjects’ redistributive choices when they have direct monetary interests in the outcome. Leaving subjects under the veil of ignorance about their relative gross income position reduces selfish behavior, also controlling for beliefs and risk attitude. Inequality aversion and fairness mostly affect redistributive choices of impartial spectators when recipients of redistribution are not informed about their initial endowments, suggesting that the luck vs. merit effect is not the only driver of redistribution on behalf of others

Epigenetic modifications of the ZNF423 gene control adipogenic commitment and are dysregulated in human hypertrophic obesity

Subcutaneous adipocyte hypertrophy is typically associated with insulin resistance and increased risk of type 2 diabetes and predicts its future development independent of obesity. In humans, subcutaneous adipose tissue hypertrophy is a consequence of impaired adipocyte precursor cell recruitment into the adipogenic pathway rather than lack of precursor cells but the molecular events responsible for the restricted adipogenesis remain unclear. The zinc-finger transcription factor (Zfp) 423 has been identified as a major determinant of preadipocyte commitment and maintained white adipose cell function. Although its levels do not change during adipogenesis, ectopic expression of Zfp423 in non-adipogenic cells is sufficient to activate peroxisome proliferator-activated receptor gamma (Pparγ) expression and to increase the adipogenic potential of these cells. In the present work, we have investigated whether Zfp423 is epigenetically regulated and whether these events are involved in the restricted adipogenesis in humans with expanded subcutaneous adipose tissue. We report here that, comparison of uncommitted (NIH-3T3) and committed (3T3-L1) adipose precursor cells revealed that Zfp423 expression increased in parallel with the ability of the cells to differentiate into mature adipocytes owing to both decreased promoter DNA methylation and nucleosome occupancy in the 3T3-L1 compared with NIH-3T3 cells. Interestingly, non-adipogenic epigenetic profiles can be reverted in NIH-3T3 cells as 5-azacytidine treatment increased Zfp423 mRNA levels, reduced DNA methylation at a specific CpG site, decreased nucleosome occupancy and induced adipocyte differentiation. These epigenetic modifications can also be initiated in response to changes in the pre-adipose cell microenvironment, in which bone morphogenetic protein 4 (Bmp4) plays a key role. We finally showed that, expression of the ZNF423 human ortholog in adipocyte precursor cells from subcutaneous adipose tissue inversely correlated to cell size of the autologous mature adipocytes. Promoter methylation at the ZNF423 regulatory region also reflected inappropriate subcutaneous adipose cell hypertrophy. As in NIH-3T3 cells, the normal ZNF423 epigenetic profile was rescued by 5-azacytidine exposure. Thus, our results show that epigenetic events regulate the ability of precursor cells to commit and differentiate into mature adipocytes by modulating ZNF423 expression, and indicate that dysregulation of these mechanisms accompanies subcutaneous adipose tissue hypertrophy in humans

Efficient photovoltaic and electroluminescent perovskite devices

Planar diode structures employing hybrid organic-inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method