Metals and dust content across the galaxies M 101 and NGC 628

We present a spatially resolved study of the relation between dust and metallicity in the nearby spiral galaxies M101 (NGC 5457) and NGC 628 (M74). We explore the relation between the chemical abundances of their gas and stars with their dust content and their chemical evolution. The empirical spatially resolved oxygen effective yield and the gas to dust mass ratio (GDR) across both disc galaxies are derived, sampling one dex in oxygen abundance. We find that the metal budget of the NGC 628 disc and most of the M101 disc appears consistent with the predictions of the simple model of chemical evolution for an oxygen yield between half and one solar, whereas the outermost region (R<0.8R25) of M101 presents deviations suggesting the presence of gas flows. The GDR-metallicity relation shows a two slopes behaviour, with a break at 12+log(O/H)~8.4, a critical metallicity predicted by theoretical dust models when stardust production equals grain growth. A relation between GDR and the fraction of molecular to total gas, Sigma(H2)/Sigma(gas) is also found. We suggest an empirical relationship between GDR and the combination of 12+log(O/H), for metallicity, and Sigma(H2)/Sigma(gas), a proxy for the molecular clouds fraction. The GDR is closely related with metallicity at low abundance and with Sigma(H2)/Sigma(gas) for higher metallicities suggesting ISM dust growth. The ratio Sigma(dust)/Sigma(star) correlates well with 12 + log(O/H) and strongly with log(N/O) in both galaxies. For abundances below the critical one, the 'stardust' production gives us a constant value suggesting a stellar dust yield similar to the oxygen yield

Planetary nebulae: abundances and abundance gradients

In this work, a review is given of some recent results and problems involved in the determination of chemical abundances of galactic planetary nebulae, particularly regarding disk and bulge objects

β-Hydroxy-β-Methylbutyrate (HMB) Promotes Neurite Outgrowth in Neuro2a Cells

β-Hydroxy-β-methylbutyrate (HMB) has been shown to enhance cell survival, differentiation and protein turnover in muscle, mainly activating phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinases/ extracellular-signal-regulated kinases (MAPK/ERK) signaling pathways. Since these two pathways are related to neuronal survival and differentiation, in this study, we have investigated the neurotrophic effects of HMB in mouse neuroblastoma Neuro2a cells. In Neuro2a cells, HMB promotes differentiation to neurites independent from any effects on proliferation. These effects are mediated by activation of both the PI3K/Akt and the extracellular-signal-regulated kinases (ERK1/2) signaling as demonstrated by the use of specific inhibitors of these two pathways. As myocyte-enhancer factor 2 (MEF2) family of transcription factors are involved in neuronal survival and plasticity, the transcriptional activity and protein levels of MEF2 were also evaluated. HMB promoted MEF2-dependent transcriptional activity mediated by the activation of Akt and ERK1/2 pathways. Furthermore, HMB increases the expression of brain glucose transporters 1 (GLUT1) and 3 (GLUT3), and mTOR phosphorylation, which translates in a higher protein synthesis in Neuro2a cells. Furthermore, Torin1 and rapamycin effects on MEF2 transcriptional activity and HMB-dependent neurite outgrowth support that HMB acts through mTORC2. Together, these findings provide clear evidence to support an important role of HMB in neurite outgrowth.This project has been funded by Abbott Nutrition R&D

Supernova environments in J-PLUS

We investigated the local environmental properties of 418 supernovae (SNe) of all types using data from the Javalambre Photometric Local Universe Survey (J-PLUS), which includes five broad-band and seven narrow-band imaging filters. Our study involves two independent analyses: (1) the normalized cumulative-rank (NCR) method, which utilizes all 12 single bands along with five continuum-subtracted narrow-band emission and absorption bands, and (2) simple stellar population (SSP) synthesis, where we build spectral energy distributions (SED) of the surrounding 1 kpc2 SN environment using the 12 broad- and narrow-band filters. Improvements on previous works include: (i) the extension of the NCR technique to other filters (broad and narrow) and the use a set of homogeneous data (same telescope and instruments); (ii) a correction for extinction to all bands based on the relation between the g − i color and the color excess E(B − V); and (iii) a correction for the contamination of the [N ii] λ6583 line that falls within the Hα filter. All NCR distributions in the broad-band filters, tracing the overall light distribution in each galaxy, are similar to each other. The main difference is that type Ia, II, and IIb SNe are preferably located in redder environments than the other SN types. The radial distribution of the SNe shows that type IIb SNe seem to have a preference for occurring in the inner regions of galaxies, whereas other types of SNe occur throughout the galaxies without a distinct preference for a specific location. For the Hα filter we recover the sequence from SNe Ic, which has the highest NCR, to SNe Ia, which has the lowest; this is interpreted as a sequence in progenitor mass and age. All core-collapse SN types are strongly correlated to the [O ii] emission, which also traces star formation rate (SFR), following the same sequence as in Hα. The NCR distributions of the Ca II triplet show a clear division between II-IIb-Ia and Ib-Ic-IIn subtypes, which is interpreted as a difference in the environmental metallicity. Regarding the SSP synthesis, we found that including the seven J-PLUS narrow filters in the fitting process has a more significant effect on the core-collapse SN environmental parameters than for SNe Ia, shifting their values toward more extincted, younger, and more star-forming environments, due to the presence of strong emission lines and stellar absorptions in those narrow bands

Fast screening of bacteria for plant growth promoting traits

Plant Growth Promoting Bacteria (PGPB) are a group of beneficial microorganisms that can positively influence plant fitness and development by improving nutrient acquisition, influencing global plant hormone levels (direct effect), or by reducing the detrimental effects of various pathogens on plant development (indirect effect). The use of PGPB in agriculture as formulated bioinoculants is a potential approach to reduce the negative environmental impacts caused by the continuous application of chemical fertilizers and pesticides. The evaluation of a great number of bacteria in the laboratory for key traits involved in the improvement of plant fitness is a suitable strategy to find prospective candidates for bioinoculants. This chapter presents the main methods described in the literature to quickly screen potential candidates from a bacterial collection to directly and indirectly promote the plant growth