Search for ionized jets towards high-mass young stellar objects

We are carrying out multi-frequency radio continuum observations, using the Australia Telescope Compact Array, to systematically search for collimated ionized jets towards high-mass young stellar objects (HMYSOs). Here we report observations at 1.4, 2.4, 4.8 and 8.6 GHz, made with angular resolutions of about 7, 4, 2, and 1 arcsec, respectively, towards six objects of a sample of 33 southern HMYSOs thought to be in very early stages of evolution. The objects in the sample were selected from radio and infrared catalogs by having positive radio spectral indices and being luminous (L_bol > 20,000 L_sun), but underluminous in radio emission compared to that expected from its bolometric luminosity. This criteria makes the radio sources good candidates for being ionized jets. As part of this systematic search, two ionized jets have been discovered: one previously published and the other reported here. The rest of the observed candidates correspond to three hypercompact hii regions and two ultracompact hii regions. The two jets discovered are associated with two of the most luminous (70,000 and 100,000 Lsun) HMYSOs known to harbor this type of objects, showing that the phenomena of collimated ionized winds appears in the formation process of stars at least up to masses of ~ 20 M_sun and provides strong evidence for a disk-mediated accretion scenario for the formation of high-mass stars. From the incidence of jets in our sample, we estimate that the jet phase in high-mass protostars lasts for 40,000 yr.Comment: Accepted for publication in the Astrophysical Journal. (53 pages, 22 Figures) (Color figures were degraded to comply with arXiv requirements

Chemistry of the High-Mass Protostellar Molecular Clump IRAS 16562-3959

We present molecular line observations of the high-mass molecular clump IRAS 16562$-$3959 taken at 3 mm using the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.\!\!^{\prime\prime}7 angular resolution ($0.014$ pc spatial resolution). This clump hosts the actively accreting high-mass young stellar object (HMYSO) G345.4938+01.4677, associated with a hypercompact HII region. We identify and analyze emission lines from 22 molecular species (encompassing 34 isomers) and classify them into two groups, depending on their spatial distribution within the clump. One of these groups gathers shock tracers (e.g., SiO, SO, HNCO) and species formed in dust grains like methanol (CH$_3$OH), ethenone or ketene (H$_2$CCO), and acetaldehyde (CH$_3$CHO). The second group collects species resembling the dust continuum emission morphology and which are formed mainly in the gas-phase, like hydrocarbons (CCH, c-C$_3$H$_2$, CH$_3$CCH), cyanopolyynes (HC$_3$N and HC$_5$N) and cyanides (HCN and CH$_3$C$_3$N). Emission from complex organic molecules (COMs) like CH$_3$OH, propanenitrile (CH$_3$CH$_2$CN), and methoxymethane (CH$_3$OCH$_3$) arise from gas in the vicinity of a hot molecular core ($T\gtrsim100$ K) associated with the HMYSO. Other COMs such as propyne (CH$_3$CCH), acrylonitrile (CH$_2$CHCN), and acetaldehyde seem to better trace warm ($T\lesssim80$ K) dense gas. In addition, deuterated ammonia (NH$_2$D) is detected mostly in the outskirts of IRAS 16562$-$3959, associated with near-infrared dark globules, probably gaseous remnants of the clump's prestellar phase. The spatial distribution of molecules in IRAS 16562$-$3959 supports the view that in protostellar clumps, chemical tracers associated with different evolutionary stages --- starless to hot cores/HII regions --- exist coevally.Comment: 97 pages, Accepted in The Astrophysical Journal Supplement Series. Journal file version have better quality figure

Slow ionized wind and rotating disklike system associated with the high-mass young stellar object G345.4938+01.4677

We report the detection, made using ALMA, of the 92 GHz continuum and hydrogen recombination lines (HRLs) H40$\alpha$, H42$\alpha$, and H50$\beta$ emission toward the ionized wind associated with the high-mass young stellar object G345.4938+01.4677. This is the luminous central dominating source located in the massive and dense molecular clump associated with IRAS 16562$-$3959. The HRLs exhibit Voigt profiles, a strong signature of Stark broadening. We successfully reproduce the observed continuum and HRLs simultaneously using a simple model of a slow ionized wind in local thermodynamic equilibrium, with no need a high-velocity component. The Lorentzian line wings imply electron densities of $5\times10^7$ cm$^{-3}$ on average. In addition, we detect SO and SO$_2$ emission arising from a compact ($\sim3000$ AU) molecular core associated with the central young star. The molecular core exhibits a velocity gradient perpendicular to the jet-axis, which we interpret as evidence of rotation. The set of observations toward G345.4938+01.4677 are consistent with it being a young high-mass star associated with a slow photo-ionized wind.Comment: (Accepted by ApJ

Fibroma osificante periférico. Reporte de un caso y revision de la literatura

En la mucosa bucal con relativa frecuencia se observan hiperplasias como el Fibroma Osificante Periférico (FOP), el cual es una lesión reactiva inflamatoria, que puede estar asociada a la presencia de traumatismos e irritantes crónicos a nivel gingival y a su vez, diversos autores en la actualidad lo asocian con un estadio maduro del Granuloma Telangiectásico. El objetivo del presente estudio, es aportar información actualizada acerca de esta patología y describir el caso clínico de una paciente de 68 años de edad, que acudió al servicio del Hospital Odontológico de la Facultad de Odontología de la Universidad Nacional del Nordeste, por presentar un abultamiento asintomático de un año aproximado de evolución, en el fondo de surco vestíbular del sector anteroinferior, el tratamiento de elección fue biopsia por escisión y eliminación de los factores desencadenantes, para de esta forma disminuir la posibilidad de recidiva

Yield and nutritive value of Urochloa hybrids at different regrowth ages

Objective: To evaluate the productive behavior of Urochloa hybrids, depending on the regrowth age. Design/Methodology/Approach: The study was carried out under rainfed conditions during 2018. The Cayman, Mulato II, Convert 330, Cobra, Camello I, and Camello II hybrids were evaluated based on the regrowth age (2, 4, 6, 8, and 10 weeks). The following variables were evaluated: plant height (PH), total dry matter (TDM) yield, dry matter per leaf (DMl) yield, dry matter per stem (DMs) yield, crude protein content (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF). The data obtained were evaluated by means of a randomized complete block design with three repetitions, divided into plots: a large plot for the cultivars and small plot for the regrowth ages. Results: The Camello II cultivar obtained the highest TDM yields during the sixth and eighth weeks (4.15 and 6.35 t DM ha-1, respectively); however, during the tenth week, the yield was equal to the yield obtained with the Mulato II and Cayman cultivars (p<0.05). The highest DMl yield was obtained by the Mulato II cultivar during the sixth, eighth, and tenth weeks (3.37, 4.56, and 3.86 t DM ha-1, respectively). The Mulato II cultivar recorded the highest CP values during the second and fourth weeks (158 and 126 g kg-1, respectively); however, the Camello II cultivar obtained the highest CP values during the sixth, eighth, and tenth weeks (99, 95, and 87 g kg-1, respectively). The NDF and ADF values increased as the regrowth age increased: in the tenth week, the Camello II and Cobra cultivars obtained the highest NDF values, while the Camello II cultivar recorded the highest ADF value during the same period. Study Limitations/Implications: Urochloa cultivars were developed for their establishment in humid tropical conditions, where their productive performance is greater. However, in dry tropical conditions, the Cayman, Mulato II, and Cobra cultivars have had a better performance than other grasses —such as buffel grass (Pennisetum ciliare), which is used to feed ruminants. In this sense, other Urochloa cultivars (e.g., Camello I and Camello II), which have greater tolerance to droughts, show desirable forage characteristics, such as yield and forage quality. Findings/Conclusions: The cultivars with the best productive performance were Camello II, Mulato II, and Cayman

Effect of Feedback of Massive Stars in the Fragmentation, Distribution, and Kinematics of the Gas in Two Star-forming Regions in the Carina Nebula

We present ALMA high spatial resolution observations toward two star-forming regions located in one of the most extreme zones of star formation in the Galaxy, the Carina Nebula. One region is located at the center of the nebula and is severally affected by the stellar feedback from high-mass stars, while the other region is located farther south and is less disturbed by the massive-star clusters. We found that the region at the center of the nebula is forming less but more massive cores than the region located in the south, suggesting that the level of stellar feedback effectively influences the fragmentation process in clumps. Lines such as HCN, HCO+, and SiO show abundant and complex gas distributions in both regions, confirming the presence of ionization and shock fronts. Jeans analysis suggests that the observed core masses in the region less affected by the massive stars are consistent with thermal fragmentation, but turbulent Jeans fragmentation might explain the high masses of the cores identified in the region in the center of Carina. Consistently, two different analyses in the HCO+ line provided evidence for a higher level of turbulence in the gas more affected by the stellar feedback. The gas column density probability functions, N-pdf’s, show lognormal shapes with clear transitions to power-law regimes. We observed a wider N-pdf in the region at the center of the nebula, which provides further evidence for a higher level of turbulence in the material with a higher level of massive stellar feedback.Indexación: Scopu

Modulo móvil de educación de la energía solar

El Módulo Móvil de Educación consiste en una casilla rodante totalmente equipada con elementos de aprovechamiento de la Energía Solar. La misma estará destinada a la educación, participando en exposiciones, charlas, conferencias, cursos, mesas redondas, sobre el tema difundiendo conocimientos teóricos y prácticos del aprovechamiento de la Energía Solar. El móvil estará equipado con las luces, agua caliente heladera TV color, vídeo, computadora hornos, cocina, potabilizador de agua, radio, ventiladores, etcétera, todas funcionando a Energía Solar, como demostrando, en forma práctica y didáctica, todas la formas de aprovechamiento.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Modulo móvil de educación de la energía solar

El Módulo Móvil de Educación consiste en una casilla rodante totalmente equipada con elementos de aprovechamiento de la Energía Solar. La misma estará destinada a la educación, participando en exposiciones, charlas, conferencias, cursos, mesas redondas, sobre el tema difundiendo conocimientos teóricos y prácticos del aprovechamiento de la Energía Solar. El móvil estará equipado con las luces, agua caliente heladera TV color, vídeo, computadora hornos, cocina, potabilizador de agua, radio, ventiladores, etcétera, todas funcionando a Energía Solar, como demostrando, en forma práctica y didáctica, todas la formas de aprovechamiento.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES