Open cluster candidates in the VVVX area: VVVX CL 076 and CL 077

We are reporting some basic parameters of two newly discovered clusters, VVVX CL 076 and CL 077, recently discovered in the galactic disk area covered by the VISTA Variables in the Via Lactea eXtended (VVVX) ESO Public Survey. The preliminary analysis shows that both clusters are young and relatively close to the Sun.Peer reviewedFinal Published versio

Investigando la zona de los cúmulos inmersos DBS 114-115-117

Se ha realizado un estudio preliminar de la poblacion estelar en la zona de los cumulos inmersosDBS 114, 115 y 117. Se ha utilizado la informacion proporcionada por varias bases de datos astronomicas y datos disponibles en la literatura. Se han incluido y correlacionado datos fotometricos en el optico (VPHAS+, GAIA), infrarrojo cercano (2MASS-VVV) e infrarrojo medio (WISE), junto con datos astrometricos (GAIA). Ademas se han realizado observaciones espectroscopicas en la banda K de estrellas seleccionadas. Este estudio ha permitido identicar diferentes tipos de fuentes: estrellas tempranas, objetos con excesos en la banda K y objetosestelares jovenes. Estos objetos han conducido a la estimacion de los parametros caractersticos de los cumulos involucrados. En particular se ha encontrado una consistencia entre los valores de distancia espectrofotometrica y trigonometrica, aunque considerando una ley de enrojecimiento levemente anormal. Se han revelado tambien evidencias de un proceso de formacion estelar secuencial.A preliminary study of the stellar population has been carried out in the area of the immersed clusters DBS 114, 115 and 117. The information provided by various astronomical databases and data available in the literature has been used. Photometric data in the optical (VPHAS +, GAIA), near infrared (2MASSVVV) and mid infrared (WISE) has been included and correlated, together with astrometric data (GAIA). In addition, spectroscopic observations have been made in the K band of selected stars. This study has made it possible to identify different types of sources: early type stars, objects with excesses in the K band and young stellar objects. These objects have led to the estimation of the characteristic parameters of the clusters involved. In particular, a consistency has been found between the spectrophotometric and trigonometric distance values, although considering a slightly abnormal reddening law. Evidence of a sequential star formation process has also been revealed.Fil: Baume, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Ramirez Alegria, S.. Universidad de Antofagasta (uantof);Fil: Borissova, J.. Universidad de Valparaíso; Chile62° Reunión Anual de la Asociación Argentina de AstronomíaRosarioArgentinaAsociación Argentina de Astronomí

The contribution of respiration in tree stems to the Dole Effect

Understanding the variability and the current value of the Dole Effect, which has been used to infer past changes in biospheric productivity, requires accurate information on the isotopic discrimination associated with respiratory oxygen consumption in each of the biosphere components. Respiration in tree stems is an important component of the land carbon cycle. Here we measured, for the first time, the discrimination associated with tree stem oxygen uptake. The measurements included tropical forest trees, which are major contributors to the global fluxes of carbon and oxygen. We found discrimination in the range of 12.6–21.5‰, indicating both diffusion limitation, resulting in O<sub>2</sub> discrimination values below 20‰, and alternative oxidase respiration, which resulted in discrimination values greater than 20‰. Discrimination varied seasonally, between and within tree species. Calculations based on these results show that variability in woody plants discrimination can result in significant variations in the global Dole Effect

Near-infrared photometry and spectroscopy of the low Galactic latitude globular cluster 2MASS-GC03

We present deep near-infrared photometry and spectroscopy of the globular cluster 2MASS-GC03 projected in the Galactic disk using MMIRS on the Clay telescope (Las Campanas Observatory) and VISTA Variables in the Via Lactea survey (VVV) data. Most probable cluster member candidates were identified from near-infrared photometry. Out of ten candidates that were followed-up spectroscopically, five have properties of cluster members, from which we calculate = -0.9 +/- 0.2 and a radial velocity of v_r > = -78 +- 12km/s. A distance of 10.8kpc is estimated from 3 likely RRLyrae members. Given that the cluster is currently at a distance of 4.2kpc from the Galactic center, the cluster's long survival time of an estimated 11.3 +/- 1.2 Gyr strengthens the case for its globular-cluster nature. The cluster has a hint of elongation in the direction of the Galactic center.Peer reviewedFinal Published versio

Vinculacion entre varios cúmulos estelares y estructuras del medio interestelar

Se estudiaron los cúmulos inmersos DBS 77, 78, 102, 160 y 161 localizados en el plano Galáctico en el cuarto cuadrante de la Vía Láctea y el medio interestelar (MIE) circundante. Se analizó fotometría UBVIc (SOAR) y espectroscopía infrarroja (NTT, ESO). Estos datos fueron complementados con las bandas JHK (VVV+2MASS), H I en 21 cm (SGPS), 1.4 GHz (ATCA) y 4.85 GHz (PMN). Se realizó un análisis multibanda y clasificación espectral de las estrellas brillantes de cada zona. Se identificaron también, estructuras del MIE posiblemente vinculadas con los cúmulos. Finalmente, se obtuvieron valores preliminares para los parámetros fundamentales de los cúmulos estudiados y de las estructuras del MIE. Se estudió la vinculación entre ambosWe study the embedded clusters DBS77, 78, 102, 160, and 161 located in the Galactic plane in the fourth quadrant of the Milky Way and the surrounding interstellar medium (ISM). We analyzed UBVIc photometry (SOAR) and infrared spectroscopy (NTT, ESO). We complemented these data with JHK (VVV2MASS), HI 21 cm bands (SGPS), 1.4 GHz (ATCA), and 4.85 GHz (PMN). We did multiband analysis and spectral classification of the brightest stars in each area. We also identified the ISM structures possibly related to the clusters. Finally, we obtained the main parameters of the studied clusters, the structures of the ISM and the link between them.Instituto de Astrofísica de La Plat

Vinculacion entre varios cúmulos estelares y estructuras del medio interestelar

Se estudiaron los cúmulos inmersos DBS 77, 78, 102, 160 y 161 localizados en el plano Galáctico en el cuarto cuadrante de la Vía Láctea y el medio interestelar (MIE) circundante. Se analizó fotometría UBVIc (SOAR) y espectroscopía infrarroja (NTT, ESO). Estos datos fueron complementados con las bandas JHK (VVV+2MASS), H I en 21 cm (SGPS), 1.4 GHz (ATCA) y 4.85 GHz (PMN). Se realizó un análisis multibanda y clasificación espectral de las estrellas brillantes de cada zona. Se identificaron también, estructuras del MIE posiblemente vinculadas con los cúmulos. Finalmente, se obtuvieron valores preliminares para los parámetros fundamentales de los cúmulos estudiados y de las estructuras del MIE. Se estudió la vinculación entre ambosWe study the embedded clusters DBS77, 78, 102, 160, and 161 located in the Galactic plane in the fourth quadrant of the Milky Way and the surrounding interstellar medium (ISM). We analyzed UBVIc photometry (SOAR) and infrared spectroscopy (NTT, ESO). We complemented these data with JHK (VVV2MASS), HI 21 cm bands (SGPS), 1.4 GHz (ATCA), and 4.85 GHz (PMN). We did multiband analysis and spectral classification of the brightest stars in each area. We also identified the ISM structures possibly related to the clusters. Finally, we obtained the main parameters of the studied clusters, the structures of the ISM and the link between them.Instituto de Astrofísica de La Plat

Vinculacion entre varios cúmulos estelares y estructuras del medio interestelar

Se estudiaron los cúmulos inmersos DBS 77, 78, 102, 160 y 161 localizados en el plano Galáctico en el cuarto cuadrante de la Vía Láctea y el medio interestelar (MIE) circundante. Se analizó fotometría UBVIc (SOAR) y espectroscopía infrarroja (NTT, ESO). Estos datos fueron complementados con las bandas JHK (VVV+2MASS), H I en 21 cm (SGPS), 1.4 GHz (ATCA) y 4.85 GHz (PMN). Se realizó un análisis multibanda y clasificación espectral de las estrellas brillantes de cada zona. Se identificaron también, estructuras del MIE posiblemente vinculadas con los cúmulos. Finalmente, se obtuvieron valores preliminares para los parámetros fundamentales de los cúmulos estudiados y de las estructuras del MIE. Se estudió la vinculación entre ambosWe study the embedded clusters DBS77, 78, 102, 160, and 161 located in the Galactic plane in the fourth quadrant of the Milky Way and the surrounding interstellar medium (ISM). We analyzed UBVIc photometry (SOAR) and infrared spectroscopy (NTT, ESO). We complemented these data with JHK (VVV2MASS), HI 21 cm bands (SGPS), 1.4 GHz (ATCA), and 4.85 GHz (PMN). We did multiband analysis and spectral classification of the brightest stars in each area. We also identified the ISM structures possibly related to the clusters. Finally, we obtained the main parameters of the studied clusters, the structures of the ISM and the link between them.Instituto de Astrofísica de La Plat

New Galactic Star Clusters Discovered in the Disk Area of the VVVX Survey

The ‘VISTA Variables in the Vía Láctea eXtended (VVVX)’ ESO Public Survey is a near-infrared photometric sky survey that covers nearly 1700 deg2 towards the Galactic disc and bulge. It is well-suited to search for new open clusters, hidden behind dust and gas. The pipeline processed and calibrated KS-band tile images of 40 per cent of the disc area covered by VVVX was visually inspected for stellar overdensities. Then, we identified cluster candidates by examination of the composite JHKS colour images. The colour-magnitude diagrams of the cluster candidates are constructed. Whenever possible the Gaia DR2 parameters are used to calculate the mean proper motions, radial velocities, reddening and distances. We report the discovery of 120 new infrared clusters and stellar groups. Approximately half of them (47 per cent) are faint, compact, highly reddened, and they seem to be associated with other indicators of recent star formation, such as nearby Young Stellar Objects, Masers, H II regions or bubbles. The preliminary distance determinations allow us to trace the clusters up to 4.5 kpc, but most of the cluster candidates are centred at 2.2 kpc. The mean proper motions of the clusters show that in general they follow the disc motion of the Galaxy

Analysis of the Zonula occludens Toxin Found in the Genome of the Chilean Non-toxigenic Vibrio parahaemolyticus Strain PMC53.7

Indexación: Scopus.Vibrio parahaemolyticus non-toxigenic strains are responsible for about 10% of acute gastroenteritis associated with this species, suggesting they harbor unique virulence factors. Zonula occludens toxin (Zot), firstly described in Vibrio cholerae, is a secreted toxin that increases intestinal permeability. Recently, we identified Zot-encoding genes in the genomes of highly cytotoxic Chilean V. parahaemolyticus strains, including the non-toxigenic clinical strain PMC53.7. To gain insights into a possible role of Zot in V. parahaemolyticus, we analyzed whether it could be responsible for cytotoxicity. However, we observed a barely positive correlation between Caco-2 cell membrane damage and Zot mRNA expression during PMC53.7 infection and non-cytotoxicity induction in response to purified PMC53.7-Zot. Unusually, we observed a particular actin disturbance on cells infected with PMC53.7. Based on this observation, we decided to compare the sequence of PMC53.7-Zot with Zot of human pathogenic species such as V. cholerae, Campylobacter concisus, Neisseria meningitidis, and other V. parahaemolyticus strains, using computational tools. The PMC53.7-Zot was compared with other toxins and identified as an endotoxin with conserved motifs in the N-terminus and a variable C-terminal region and without FCIGRL peptide. Notably, the C-terminal diversity among Zots meant that not all of them could be identified as toxins. Structurally, PMC53.7-Zot was modeled as a transmembrane protein. Our results suggested that it has partial 3D structure similarity with V. cholerae-Zot. Probably, the PMC53.7-Zot would affect the actin cytoskeletal, but, in the absence of FCIGRL, the mechanisms of actions must be elucidated. © Copyright © 2020 Pérez-Reytor, Pavón, Lopez-Joven, Ramírez-Araya, Peña-Varas, Plaza, Alegría-Arcos, Corsini, Jaña, Pavez, del Pozo, Bastías, Blondel, Ramírez and García.https://www.frontiersin.org/articles/10.3389/fcimb.2020.00482/ful