2,684 research outputs found
Spatially resolved star formation main sequence of galaxies in the CALIFA survey
Astrophysical Journal Letters 821.2 (2016): L26 reproduced by permission of the AASThe "main sequence of galaxies" - defined in terms of the total star formation rate ψ versus the total stellar mass M∗ - is a well-studied tight relation that has been observed at several wavelengths and at different redshifts. All earlier studies have derived this relation from integrated properties of galaxies. We recover the same relation from an analysis of spatially resolved properties, with integral field spectroscopic (IFS) observations of 306 galaxies from the CALIFA survey. We consider the SFR surface density in units of log (Mo yr-1 Kpc-2) and the stellar mass surface density in units of log (Mo Kpc-2) in individual spaxels that probe spatial scales of 0.5-1.5 Kpc. This local relation exhibits a high degree of correlation with small scatter (σ = 0.23 dex), irrespective of the dominant ionization source of the host galaxy or its integrated stellar mass. We highlight (i) the integrated star formation main sequence formed by galaxies whose dominant ionization process is related to star formation, for which we find a slope of 0.81 ± 0.02; (ii) for the spatially resolved relation obtained with the spaxel analysis, we find a slope of 0.72 ± 0.04; and (iii) for the integrated main sequence, we also identified a sequence formed by galaxies that are dominated by an old stellar population, which we have called the retired galaxies sequenceFinancial support: M.C.D. and S.F.S.: DGAPA-UNAM funding; CONACyT-180125 and PAPIIT IA- 100815 projects. Z.S.: EU Marie Curie Career Integration Grant ”SteMaGE” PCIG12-GA-2012-326466. Y.A.: RyC- 2011-09461 and AYA2013-47742-C4-3-P projects from the Spanish MINECO and the SELGIFS programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701). C.J.W.: Marie Curie Career Integration Grant 303912. R.M.G.D.: AyA2014- 57490-P and J.A. P12-FQM2828 grants. J.F.B.: AYA2013- 48226-C3-1-P from the Spanish MINECO grant. L.G.: Millennium Science Initiative through grant IC120009, and by CONICYT through FONDECYT grant 314056
Microfaunal soil food webs in Mediterranean semi-arid agroecosystems. Does organic management improve soil health?
Soil food webs, which are responsible for relevant ecological functions in agroecosystems such as nutrient cycling and pest and disease suppression, represent a crucial aspect of agricultural sustainability. We studied soil properties and microfaunal food web diversity and functioning in six paired organic and conventional fields located in Central Spain to assess the effects of organic farming on soil diversity and functioning in semi-arid conditions. We hypothesized that organic farming may enhance functioning of soil food webs. Our results showed larger differences between crop types, namely olive groves and vineyards, than between farming scheme, i.e. organic and conventional fields, and few benefits of organic farming in terms of soil fertility. Soil properties (total N, C, and P, available P and K, electrical conductivity, NH4+, NO3−, soil moisture, pH) tended to present higher values in vineyards than in olive groves and in conventional than in organic fields. Some plant-parasitic nematodes were associated to organic fields, especially in vineyards, and all soils fell within a degraded soil food web condition, with low Structure and Enrichment Index values. Nematode metabolic footprints showed relevant seasonal dynamics, with the more intensive herbivore activity in spring. We conclude that the lack of conventional pesticides and mineral fertilizers is probably not enough to improve soil conservation in semi-arid Mediterranean agroecosystems, and thus active soil conservation practices, as reduced tillage or cover cropping, are required to increase agroecosystem sustainability.Fundación Internacional para la Restauración de EcosistemasMinisterio de Economía y Competitivida
Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale
We present a study of the HII regions in the galaxy NGC 6754 from a two
pointing mosaic comprising 197,637 individual spectra, using Integral Field
Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science
Verification program. The data cover the entire galaxy out to ~2 effective
radii (re ), sampling its morphological structures with unprecedented spatial
resolution for a wide-field IFU. A complete census of the H ii regions limited
by the atmospheric seeing conditions was derived, comprising 396 individual
ionized sources. This is one of the largest and most complete catalogue of H ii
regions with spectroscopic information in a single galaxy. We use this
catalogue to derive the radial abundance gradient in this SBb galaxy, finding a
negative gradient with a slope consistent with the characteristic value for
disk galaxies recently reported. The large number of H ii regions allow us to
estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong
constraints on the proposed mechanisms for metal mixing in disk galaxies, like
radial movements associated with bars and spiral arms, when comparing with
simulations. We found evidence for an azimuthal variation of the oxygen
abundance, that may be related with the radial migration. These results
illustrate the unique capabilities of MUSE for the study of the enrichment
mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&
Complete and versatile remote controller for PV systems
The promotion of the distributed generation and the photovoltaic (PV) energy great potential put this technology in the spotlight of investors. Thus, the optimization of its efficiency is made a priority. In this paper, a complete and versatile remote controller (C&VRC) for PV systems is presented, scalable to any kind and size of installations (with or without partial shading, with or without connection to the grid, housing, small plants or even large-scale solar plants) and valid for any weather conditions. The C&VRC involves the controller itself, which is constituted by a set of sensors and actuators connected to the converters Direct Current (DC)/DC and DC/Alternating Current (AC), if necessary, and a control unit communicated with them through the third-generation mobile telecommunications technology (3G) network. The control strategies can be changed according to the different weather conditions and installations characteristics, which guaranties the optimum performance of the system. The use of the 3G network as communication platform makes the C&VRC useful in remote and low accessibility places, because it is the most extended worldwide. The C&VRC is also based on free software, open hardware and low-cost electronic devices. Experimental results are presented in this paper to show the C&VRC optimum usability.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA
Surgical ciliated cyst of the maxilla. Clinical case
Surgical ciliated cyst is uncommon in Western countries but frequently reported in Asian populations as a delayed complication of surgery, with inclusion in the bone of nasal or sinus mucosa. Isolated cases have also been reported in the mandible after orthognathic surgery. We report a case in the maxillary region three years after radical sinus surgery for chronic sinusitis. Intraoral examination revealed a small painless tumefaction with no color change in the surrounding tissues. Computed tomography demonstrated a well-defined intraosseous lesion lateral to the maxillary sinus. The lesion was completely excised, when histology demonstrated a pseudostratified ciliated epithelial lining. Differential diagnosis from other lesions such as an odontogenic keratocyst or inflammatory cyst were also made. This case report,uncommon in Western countries, of a surgical ciliated cyst illustrates the need for a meticulous surgical technique, proper management of complications, and routine, long-term follow-up of patients undergoing any type of sinus surgery
SDSS IV MaNGA: Dependence of Global and Spatially Resolved SFR-M ∗ Relations on Galaxy Properties
Indexación: Scopus.The galaxy integrated Hα star formation rate-stellar mass relation, or SFR(global)-M ∗(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different Hα powering sources for ∼1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially resolved relation between Hα surface density (ΣHα(all)) and stellar mass surface density (Σ∗(all)) progressively turns over at the high Σ∗(all) end for increasing M ∗(global) and/or bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated Hα(global)-M ∗(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated Hα(H ii)-M ∗(H ii) and spatially resolved ΣHα(H ii)-Σ∗(H ii) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. An analysis of the fractional contribution of non-star-formation sources to total Hα luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR-M ∗ relation critically depends on their global properties (M ∗(global) and B/T) and relative abundances of various ionizing sources within the galaxies.http://iopscience.iop.org/article/10.3847/1538-4357/aaa9bc/met
Retrieval of ionospheric profiles from the Mars Express MARSIS experiment data and comparison with radio occultation data
Abstract. Since 2005 the Mars Advanced Radar and Ionospheric Sounding experiment (MARSIS) aboard Mars Express has acquired a unique dataset on the ionosphere of Mars made up of ionospheric soundings taken by the instrument working in its active ionospheric sounding (AIS) mode. These soundings play a role similar to those of modern Terrestrial digisondes in the analysis of our planet ionosphere and have allowed us to dramatically improve our knowledge about the Martian ionosphere. This paper describes this kind of data, which are available from the public Planetary Science Archive, and introduces the MAISDAT tool developed by the European Space Agency to analyze and derive the vertical profile of electron density. Comparisons with radio occultation profiles obtained from Mars Express Radio Science instrument are performed to validate the procedure used in this study
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