A Spectroscopic Study of the Near-IR [SIII] Lines in a Sample of HII Galaxies: chemical abundances

A detailed spectroscopic study, from lambda 3700 A to 1 um, was performed for a sample of 34 HII galaxies in order to derive fundamental parameters for their HII regions and ionizing sources, as well as gaseous metal abundances. All the spectra included the nebular [SIII]9069,9532 A lines, given their importance in the derivation of the S/H abundance and relevant ionization diagnostics. A systematic method was followed to correct the near-IR [SIII] line fluxes for the effects of the atmospheric transmission.A comparative analysis of the predictions of the empirical abundance indicators R23 and S23 has been performed. The relative hardness of their ionizing sources was studied using the eta parameter, and exploring the role played by metallicity. For 22 galaxies of the sample a direct value of te[SIII] was derived, along with their ionic and total S/H abundances. Their ionic and total O/H abundances were derived using direct determinations of te[OIII].For the rest of the objects, the total S/H abundance was derived using S23. The abundance range covered by our sample goes from 1/20 solar up to solar metallicity. The mean S/O ratio derived is log (S/O)=-1.68+/-0.20 dex, 1 sigma below the solar S/O value. The S/O abundance ratio shows no significant trend with O/H over the range of abundance covered in this work, in agreement with previous findings.There is a trend for HII galaxies with lower gaseous metallicity to present harder ionizing spectra. We compared the distribution of the ionic ratios O+/O++ vs. S+/S++ derived for our sample with the predictions of a grid of photoionization models performed for different stellar effective temperatures. This analysis indicates that a large fraction of galaxies in our sample seem to be ionized by extremely hard spectra.Comment: 12 pages, 8 figures, accepted for publication in the A&A, minor gramatical corrections include

Exposure of pineapple shoot tips to liquid nitrogen and cryostorage do not affect the histological status of regenerated plantlets

[EN] Conservation of pineapple (Ananas comosus L. Merr.) genetic resources - including cryopreservation in liquid N-2 at -196 degrees C - is essential for future breeding programmes to develop new varieties with improved agronomic performance. However, the potentially deleterious effects of cryopreservation on subsequent plant regrowth should be evaluated before large-scale development of cryobanks is implemented. This paper describes the histological analysis of pineapple plantlets regenerated from cryopreserved shoot tips. Two controls were included in the study: i) conventional micropropagation-derived plantlets, and ii) plants from shoot tips subjected to pre-cryostorage conditioning treatments but never exposed to liquid N-2. Histological studies of roots, leaves and stems were conducted after 45 days of hardening. No statistically significant differences with the controls were observed in any of the histological parameters evaluated, which supports the practical value of cryopreservation of pineapple germplasm.This research was supported by the Bioplant Centre (Cuba), the Escuela Superior Politecnica Agropecuaria de Manabi Manuel Felix Lopez (Ecuador), the IRD Representation in Benin, and the Universitat Politecnica de Valencia (Spain).Villalobos-Olivera, A.; Nápoles, L.; Mendoza, JR.; Escalante, D.; Martínez, J.; Concepción, O.; Zevallos, BE.... (2019). Exposure of pineapple shoot tips to liquid nitrogen and cryostorage do not affect the histological status of regenerated plantlets. Romanian Biotechnological Letters. 24(6):1061-1066. https://doi.org/10.25083/rbl/24.6/1061.1066S1061106624

First survey of Wolf-Rayet star populations over the full extension of nearby galaxies observed with CALIFA

The search of extragalactic regions with conspicuous presence of Wolf-Rayet (WR) stars outside the Local Group is challenging task due to the difficulties in detecting their faint spectral features. In this exploratory work, we develop a methodology to perform an automated search of WR signatures through a pixel-by-pixel analysis of integral field spectroscopy (IFS) data belonging to the Calar Alto Legacy Integral Field Area survey, CALIFA. This technique allowed us to build the first catalogue of Wolf-Rayet rich regions with spatially-resolved information, allowing to study the properties of these complexes in a 2D context. The detection technique is based on the identification of the blue WR bump (around He II 4686 {\AA}, mainly associated to nitrogen-rich WR stars, WN) and the red WR bump (around C IV 5808 {\AA} and associated to carbon-rich WR stars, WC) using a pixel-by-pixel analysis. We identified 44 WR-rich regions with blue bumps distributed in 25 galaxies of a total of 558. The red WR bump was identified only in 5 of those regions. We found that the majority of the galaxies hosting WR populations in our sample are involved in some kind of interaction process. Half of the host galaxies share some properties with gamma-ray burst (GRB) hosts where WR stars, as potential candidates to being the progenitors of GRBs, are found. We also compared the WR properties derived from the CALIFA data with stellar population synthesis models, and confirm that simple star models are generally not able to reproduce the observations. We conclude that other effects, such as the binary star channel (which could extend the WR phase up to 10 Myr), fast rotation or other physical processes that causes the loss of observed Lyman continuum photons, are very likely affecting the derived WR properties, and hence should be considered when modelling the evolution of massive stars.Comment: 33 pages, accepted for publication in A&

Aperture effects on the oxygen abundance determinations from CALIFA data

This paper aims at providing aperture corrections for emission lines in a sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey (CALIFA) database. In particular, we explore the behavior of the log([OIII]5007/Hbeta)/([NII]6583/Halpha) (O3N2) and log[NII]6583/Halpha (N2) flux ratios since they are closely connected to different empirical calibrations of the oxygen abundances in star forming galaxies. We compute median growth curves of Halpha, Halpha/Hbeta, O3N2 and N2 up to 2.5R_50 and 1.5 disk R_eff. The growth curves simulate the effect of observing galaxies through apertures of varying radii. The median growth curve of the Halpha/Hbeta ratio monotonically decreases from the center towards larger radii, showing for small apertures a maximum value of ~10% larger than the integrated one. The median growth curve of N2 shows a similar behavior, decreasing from the center towards larger radii. No strong dependence is seen with the inclination, morphological type and stellar mass for these growth curves. Finally, the median growth curve of O3N2 increases monotonically with radius. However, at small radii it shows systematically higher values for galaxies of earlier morphological types and for high stellar mass galaxies. Applying our aperture corrections to a sample of galaxies from the SDSS survey at 0.02<=z<=0.3 shows that the average difference between fiber-based and aperture corrected oxygen abundances, for different galaxy stellar mass and redshift ranges, reaches typically to ~11%, depending on the abundance calibration used. This average difference is found to be systematically biased, though still within the typical uncertainties of oxygen abundances derived from empirical calibrations. Caution must be exercised when using observations of galaxies for small radii (e.g. below 0.5R_eff) given the high dispersion shown around the median growth curves.Comment: Accepted for publication in Ap

Design Of A Minicomputer Separator Of Urban Solid Waste (RSU)

In Mexico, the society in general lacks the habit and ethics of properly disposing garbage or in taking care of the environment. This paper focuses on analyzing and disposing garbage in an automated way. The present study also seeks to create and promote care for the planet. The minicomputer (GreenScanProcess) is an automated system whose process is based on an algorithm that stands out for its functionality. GreenScanProcess has sensors that allow the analysis and scanning of garbage. It also measures the weight and humidity of the garbage. The minicomputer also examines the garbage to know its composition. Likewise, GreenScanProcess takes the garbage to the container according to the garbage. The benefits obtained when conducting the research were: environmental, economic, technological, and educational

Planetary nebulae in M33: probes of AGB nucleosynthesis and ISM abundances

We have obtained deep optical spectrophotometry of 16 planetary nebulae in M33, mostly located in the central two kpc of the galaxy, with the Subaru and Keck telescopes. We have derived electron temperatures and chemical abundances from the detection of the [OIII]4363 line for the whole sample. We have found one object with an extreme nitrogen abundance, 12+log(N/H)=9.20, accompanied by a large helium content. After combining our data with those available in the literature for PNe and HII regions, we have examined the behavior of nitrogen, neon, oxygen and argon in relation to each other, and as a function of galactocentric distance. We confirm the good correlation between Ne/H and O/H for PNe in M33. Ar/H is also found to correlate with O/H. This strengthens the idea that at the metallicity of the bright PNe analyzed in M33, which is similar to that found in the LMC, these elements have not been significantly modified during the dredge-up processes that take place during the AGB phase of their progenitor stars. We find no significant oxygen abundance offset between PNe and HII regions at any given galactocentric distance, despite the fact that these objects represent different age groups in the evolution of the galaxy. Combining the results from PNe and HII regions, we obtain a representative slope of the ISM alpha-element (O, Ar, Ne) abundance gradient in M33 of -0.025 +/- 0.006 dex/kpc. Both PNe and HII regions display a large abundance dispersion at any given distance from the galactic center. We find that the N/O ratio in PNe is enhanced, relative to the HII regions, by approximately 0.8 dex.Comment: 21 pages, 20 figures. Accepted for publication in MNRA

Trimethylamine-N-Oxide (TMAO) Predicts Cardiovascular Mortality in Peripheral Artery Disease

Peripheral artery disease (PAD) is a major cause of acute and chronic illness, with extremely poor prognosis that remains underdiagnosed and undertreated. Trimethylamine-N-Oxide (TMAO), a gut derived metabolite, has been associated with atherosclerotic burden. We determined plasma levels of TMAO by mass spectrometry and evaluated their association with PAD severity and prognosis. 262 symptomatic PAD patients (mean age 70 years, 87% men) categorized in intermittent claudication (IC, n = 147) and critical limb ischemia (CLI, n = 115) were followed-up for a mean average of 4 years (min 1-max 102 months). TMAO levels were increased in CLI compared to IC (P 2.26 µmol/L exhibited higher risk of cardiovascular death (sub-hazard ratios ≥2, P < 0.05) that remained significant after adjustment for confounding factors. TMAO levels were associated to disease severity and CV-mortality in our cohort, suggesting an improvement of PAD prognosis with the measurement of TMAO. Overall, our results indicate that the intestinal bacterial function, together with the activity of key hepatic enzymes for TMA oxidation (FMO3) and renal function, should be considered when designing therapeutic strategies to control gut-derived metabolites in vascular patients

VOLUMEN 15, NÚMERO 29 (1981-1982)

USO DEL COMPUTADOR EN EL ANÁLISIS SEDIMENTOLÓGICO Y DE MIGRACIÓN DE FLUIDOS Y SU APLICACIÓN EN EL NOROCCIDENTE COLOMBIANO. Castro, A. E.; Molina, G. J.UN MODELO ESTRUCTURAL PARA EL VALLE DEL CAUCA Y SUS IMPLICACIONES HIDROGEOLÓGICAS Y MINERAS. Padilla, L. E.TECTÓNICA DE SOBRECORRIMIENTO Y SUS IMPLICACIONES ESTRUCTURALES EN EL ÁREA PAMPLONA - CORDILLERA ORIENTAL DE COLOMBIA. Boinet, T.; Bourgois, J.; Mendoza F. HGEOLOGÍA DE LAS LATERITAS NIQUELÍFERAS DE CERRO MATOSO S. A. Mejía, V. M.; Durango, J. R.COMPLEJO OFIOLÍTICO EN LA CUENCA DEL RÍO GUAPI. Ortega Montero, C.DETERMINACIÓN DE RESERVAS DE DEPÓSITOS MINERALES. Hernández Garay, H.CARACTERIZACIÓN, RANGO Y CLASIFICACIÓN DE CARBONES. Ramírez Castro, P

VOLUMEN 15, NÚMERO 29 (1981-1982)

USO DEL COMPUTADOR EN EL ANÁLISIS SEDIMENTOLÓGICO Y DE MIGRACIÓN DE FLUIDOS Y SU APLICACIÓN EN EL NOROCCIDENTE COLOMBIANO. Castro, A. E.; Molina, G. J.UN MODELO ESTRUCTURAL PARA EL VALLE DEL CAUCA Y SUS IMPLICACIONES HIDROGEOLÓGICAS Y MINERAS. Padilla, L. E.TECTÓNICA DE SOBRECORRIMIENTO Y SUS IMPLICACIONES ESTRUCTURALES EN EL ÁREA PAMPLONA - CORDILLERA ORIENTAL DE COLOMBIA. Boinet, T.; Bourgois, J.; Mendoza F. HGEOLOGÍA DE LAS LATERITAS NIQUELÍFERAS DE CERRO MATOSO S. A. Mejía, V. M.; Durango, J. R.COMPLEJO OFIOLÍTICO EN LA CUENCA DEL RÍO GUAPI. Ortega Montero, C.DETERMINACIÓN DE RESERVAS DE DEPÓSITOS MINERALES. Hernández Garay, H.CARACTERIZACIÓN, RANGO Y CLASIFICACIÓN DE CARBONES. Ramírez Castro, P