The prevalence and properties of cold gas inflows and outflows around galaxies in the local Universe

We perform a stacking analysis of the neutral \nad\,$\lambda\lambda$5889,5895\,\AA\ ISM doublet using the SDSS DR7 spectroscopic data set to probe the prevalence and characteristics of cold (T\,$\lesssim$\,10$^{4}$\,K) galactic-scale gas flows in local (0.025$\leqslant z\leqslant$0.1) inactive and AGN-host galaxies across the SFR-M$_{*}$ plane. We find low-velocity outflows to be prevalent in regions of high SFRs and stellar masses (10 $\lesssim$log M$_{*}$/M$_{\odot}$ $\lesssim$ 11.5), however we do not find any detections in the low mass (log M$_{*}$/M$_{\odot}$ $\lesssim$ 10) regime. We also find tentative detections of inflowing gas in high mass galaxies across the star-forming population. We derive mass outflow rates in the range of 0.14-1.74\,M$_{\odot}$yr$^{-1}$ and upper limits on inflow rates <1\,M$_{\odot}$yr$^{-1}$, allowing us to place constraints on the mass loading factor ($\eta$=$\dot{M}_{\text{out}}$/SFR) for use in simulations of the local Universe. We discuss the fate of the outflows by comparing the force provided by the starburst to the critical force needed to push the outflow outward, and find the vast majority of the outflows unlikely to escape the host system. Finally, as outflow detection rates and central velocities do not vary strongly with the presence of a (weak) active supermassive black hole, we determine that star formation appears to be the primary driver of outflows at $z\sim$0.Comment: Accepted in MNRAS. 36 pages, 15 figure

Aquaporins in Sensory and Pain Transmission

Recent data suggest a possible involvement of Aquaporins (AQPs) in pain transmission. AQPs are small membrane channel proteins involved in osmoregulation and, to date, AQP1, AQP2, AQP3, AQP4, AQP5, AQP8 and AQP9 have been found in the nervous system. Nevertheless only AQP1, AQP2 and AQP4 seem to be involved in nociception

A multi-approach for understanding the root growth under hydric deficiency

Plants, as sessile organisms, should be adapted to a wide range of changes in the surrounding environment, so they have several mechanisms focused on minimizing the impact of these changes. The limited success of classical breeding programs in increasing tolerance to environmental stress factors has spurred efforts to understand the physiological mechanisms and the genetic regulation of abiotic stress. In this context, we focus our work on elucidating new components involved in plant abiotic stress tolerance. Build on our study several experimental strategies to explain the role of root systems in drought tolerance. Studying the root at different levels, including cells, tissue, and organs, could give a big picture of how the root responds to drought conditions and which responses could be associated with tolerance mechanisms.Agencia Nacional de Investigación e InnovaciónUniversidad de la República. Comisión Sectorial de Investigación Científic

Galactic-Scale Outflows in Galaxies of the Local Universe

Galactic-scale gas outflows form a crucial ingredient in today’s galaxy evolution mod- els and are thought to regulate the gas contents - and therefore evolution - of galaxies. However, outflows are poorly understood, and thus far have been studied primarily in extreme objects rather than the normal star-forming populations. As such, several out- standing questions remain and determining the prevalence and properties of outflows in normal, star-forming galaxies, as well as their quenching potential is a prerequisite towards obtaining a complete picture of galaxy evolution. Specifically, major questions include: What is the prevalence of outflows in normal galaxies and what are their main drivers and properties? Are the properties of outflows enhanced by the presence of an AGN? What are the kpc-scale properties of outflows? Are outflows seen in all gas phases and what are their relative fractions? This Thesis aims to answers these questions by making use of the largest integrated and IFU spectroscopic data sets currently available such as the SDSS, MaNGA, xCOLD GASS, xGASS and ALFALFA surveys. Using the NaD ISM doublet and a variety of stacking techniques, we investigate the large-scale prevalence and properties of outflows in normal galaxies at z ∼0 with SDSS spectra, the kpc-scale outflow properties and their relation to galaxy properties with MaNGA IFU spectra, and finally investigate the multi- phase (i.e., molecular, neutral and ionised) nature of outflows with a stacking analysis of CO(1-0), H i 21cm, NaD and Hα tracers using the xCOLD GASS, xGASS, ALFALFA and MaNGA surveys. The Thesis finishes off with the investigation of the possible presence of a molecular gas outflow in a high redshift, lensed galaxy for which multitransitional CO and C i spectra were obtained with the IRAM 30m telescope

A spectroscopic search for AGN activity in the reionization era

The ubiquity of Lyman alpha (Ly$\alpha$) emission in a sample of four bright [O III]-strong star-forming galaxies with redshifts above 7 has led to the suggestion that such luminous sources represent a distinct population compared to their fainter, more numerous, counterparts. The presence of Ly$\alpha$ emission within the reionization era could indicate that these sources created early ionized bubbles due to their unusually strong radiation, possibly due to the presence of active galactic nuclei. To test this hypothesis we have secured long integration spectra with XSHOOTER on the VLT for three $z\simeq$7 sources selected to have similar luminosities and prominent excess fluxes in the IRAC 3.6 or 4.5$\mu$m band, usually attributed to strong [O III] emission. We secured additional spectroscopy for one of these galaxies at $z$=7.15 using MOSFIRE at the Keck telescope. For this, the most well-studied source in our sample with the strongest IRAC excess, we detect prominent nebular emission from He II and NV indicative of a non-thermal source. For the other two sources at $z$=6.81 and $z$=6.85, for which no previous optical/near infrared spectroscopy was initially available, Ly$\alpha$ is seen in one and CIII] emission in the other. Although a modest sample, our results further support the hypothesis that the phenomenon of intense [O III] emission is associated preferentially with sources lying in early ionized bubbles. However, even though one of our sources at $z$=7.15 clearly indicates the presence of non-thermal radiation, such ionized bubbles may not uniquely arise in this manner. We discuss the unique advantages of extending such challenging diagnostic studies with JWST.Comment: 11 pages, 7 figures, submitted to Ap

The down-regulation of pank2 gene in zebrafish as a model of Pantothenate Kinase Associated Neurodegeneration.

open9siThe increased iron deposition is a hallmark of many neurodegenerative diseases, but its pathogenic role is still unclear. A strong link between iron and neurodegeneration is evident in a set of heterogeneous neurological disorders, known as Neurodegeneration with Brain Iron Accumulation (NBIA). The most common form of inherited NBIA is associated with mutations in hPank2 gene (PKAN). Pank2 is the rate limiting enzyme in CoA biosynthesis and its downregulation in mammalian cells leads to perturbation of cellular iron homeostasis. Here we explore Pank2 biological function in Danio rerio, and propose this system as an important new tool for the study of PKAN disease.openZizioli, Daniela; Tiso, Natascia; Busolin, Giorgia; Khatri, Deepak; Giuliani, Roberta; Borsani, Giuseppe; Monti, Eugenio; Argenton, Francesco; Finazzi, DarioZizioli, Daniela; Tiso, Natascia; Busolin, Giorgia; Khatri, Deepak; Giuliani, Roberta; Borsani, Giuseppe; Monti, Eugenio; Argenton, Francesco; Finazzi, Dari

A comparison of melatonin and α-lipoic acid in the induction of antioxidant defences in L6 rat skeletal muscle cells.

Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. The loss of cells during aging in vital tissues and organs is related to several factors including oxidative stress and inflammation. Skeletal muscle degeneration is common in elderly people; in fact, this tissue is particularly vulnerable to oxidative stress since it requires large amounts of oxygen, and thus, oxidative damage is abundant and accumulates with increasing age. Melatonin (N-acetyl-5-methoxytryptamine) is a highly efficient scavenger of reactive oxygen species and it also exhibits beneficial anti-inflammatory and anti-aging effects. This study investigated the susceptibility of rat L6 skeletal muscle cells to an induced oxidative stress following their exposure to hydrogen peroxide (50 μM) and evaluating the potential protective effects of pre-treatment with melatonin (10 nM) compared to the known beneficial effect of alpha-lipoic acid (300 μM). Hydrogen peroxide-induced obvious oxidative stress; it increased the expression of tumour necrosis factor-alpha and in turn promoted nuclear factor kappa-B and overrode the endogenous defence mechanisms. Conversely, pre-treatment of the hydrogen peroxide-exposed cells to melatonin or alpha-lipoic acid increased endogenous antioxidant enzymes, including superoxide dismutase-2 and heme oxygenase-1; moreover, they ameliorated significantly oxidative stress damage and partially reduced alterations in the muscle cells, which are typical of aging. In conclusion, melatonin was equally effective as alpha-lipoic acid; it exhibited marked antioxidant and anti-aging effects at the level of skeletal muscle in vitro even when it was given in a much lower dose than alpha-lipoic acid

Newly Discovered Bright z~9-10 Galaxies and Improved Constraints on Their Prevalence Using the Full CANDELS Area

We report the results of an expanded search for z~9-10 candidates over the ~883 arcmin^2 CANDELS+ERS fields. This study adds 147 arcmin^2 to the search area we consider over the CANDELS COSMOS, UDS, and EGS fields, while expanding our selection to include sources with bluer J_{125}-H_{160} colors than our previous J_{125}-H_{160}>0.5 mag selection. In searching for new z~9-10 candidates, we make full use of all available HST, Spitzer/IRAC, and ground-based imaging data. As a result of our expanded search and use of broader color criteria, 3 new candidate z~9-10 galaxies are identified. We also find again the z=8.683 source previously confirmed by Zitrin+2015. This brings our sample of probable z~9-11 galaxy candidates over the CANDELS+ERS fields to 19 sources in total, equivalent to 1 candidate per 47 arcmin^2 (1 per 10 WFC3/IR fields). To be comprehensive, we also discuss 28 mostly lower likelihood z~9-10 candidates, including some sources that seem to be reliably at z>8 using the HST+IRAC data alone, but which the ground-based data show are much more likely at z<4. One case example is a bright z~9.4 candidate COS910-8 which seems instead to be at z~2. Based on this expanded sample, we obtain a more robust LF at z~9 and improved constraints on the volume density of bright z~9 and z~10 galaxies. Our improved z~9-10 results again reinforce previous findings for strong evolution in the UV LF at z>8, with a factor of ~10 evolution seen in the luminosity density from z~10 to z~8.Comment: 22 pages, 12 figures, 6 tables, accepted for publication in the Astrophysical Journa