Explosive Disintegration of a Massive Young Stellar System in Orion

Young massive stars in the center of crowded star clusters are expected to undergo close dynamical encounters that could lead to energetic, explosive events. However, there has so far never been clear observational evidence of such a remarkable phenomenon. We here report new interferometric observations made with the Submillimeter Array (SMA) that indicate the well known enigmatic wide-angle outflow located in the Orion BN/KL star-forming region to have been produced by such a violent explosion during the disruption of a massive young stellar system, and that this was caused by a close dynamical interaction about 500 years ago. This outflow thus belongs to a totally different family of molecular flows which is not related to the classical bipolar flows that are generated by stars during their formation process. Our molecular data allow us to create a 3D view of the debris flow and to link this directly to the well known Orion H$_2$ "fingers" farther outComment: Accepted by ApJ Letters The 3D movie can be found in: ftp://ftp.mpifr-bonn.mpg.de/outgoing/lzapata/movie.gi

Construction and characterization of a partial binary bacterial artificial chromosome (BIBAC) of Agave tequilana var. azul (2X) and its application for gene identification

The structure and organization of the genome of Agave is still unknown. To provide a genomic tool for searching sequences of the genus, we built and characterized a binary (BIBAC2) genomic library of Agave tequilana  Weber var. azul. Clones of the library had an average insert size of 170 Kb. The frequency of inserts with  internal Not I sites was 30% and only 5% of the library showed organelle contamination. The library was  assessed using probes with high homology to repeated regions (retroelements and rDNA regions), genes  involved in the resistance to diseases (NBS-LRR) and genes related to late embryogenesis (LEA).  Recombinant clones that hybridized with each of the probes were identified. Our results indicate that the  obtained genomic library is suitable for the identification of sequences of interest, for genetic mapping and for studies of gene regulation and expression.Key words: Binary bacterial artificial chromosome (BIBAC), Agave tequilana, genome, clones

Orion KL: The hot core that is not a "Hot Core"

We present sensitive high angular resolution submillimeter and millimeter observations of torsionally/vibrationally highly excited lines of the CH$_3$OH, HC$_3$N, SO$_2$, and CH$_3$CN molecules and of the continuum emission at 870 and 1300 $\mu$m from the Orion KL region, made with the Submillimeter Array (SMA). These observations plus recent SMA CO J=3-2 and J=2-1 imaging of the explosive flow originating in this region, which is related to the non-hierarchical disintegration of a massive young stellar system, suggest that the molecular Orion "Hot Core" is a pre-existing density enhancement heated from the outside by the explosive event -- unlike in other hot cores we do not find any self-luminous submillimeter, radio or infrared source embedded in the hot molecular gas. Indeed, we do not observe filamentary CO flow structures or "fingers" in the shadow of the hot core pointing away from the explosion center. The low-excitation CH$_3$CN emission shows the typical molecular heart-shaped structure, traditionally named the Hot Core, and is centered close to the dynamical origin of the explosion. The highest excitation CH$_3$CN lines are all arising from the northeast lobe of the heart-shaped structure, {\it i. e.} from the densest and most highly obscured parts of the Extended Ridge. The torsionally excited CH$_3$OH and vibrationally excited HC$_3$N lines appear to form a shell around the strongest submillimeter continuum source. Surprisingly the kinematics of the Hot Core and Compact Ridge regions as traced by CH$_3$CN and HC$_3$N also reveal filament-like structures that emerge from the dynamical origin. All of these observations suggest the southeast and southwest sectors of the explosive flow to have impinged on a pre-existing very dense part of the Extended Ridge, thus creating the bright Orion KL Hot Core.Comment: Submitted to A&

On the kinematics of massive star forming regions: the case of IRAS 17233-3606

Direct observations of accretion disks around high-mass young stellar objects would help to discriminate between different models of formation of massive stars. However, given the complexity of massive star forming regions, such studies are still limited in number. Additionally, there is still no general consensus on the molecular tracers to be used for such investigations. Because of its close distance and high luminosity, IRAS 17233-3606 is a potential good laboratory to search for traces of rotation in the inner gas around the protostar(s). Therefore, we selected the source for a detailed analysis of its molecular emission at 230 GHz with the SMA. We systematically investigated the velocity fields of transitions in the SMA spectra which are not affected by overlap with other transitions, and searched for coherent velocity gradients to compare them to the distribution of outflows in the region. Beside CO emission we also used high-angular H2 images to trace the outflow motions driven by the IRAS 17233-3606 cluster. We find linear velocity gradients in many transitions of the same molecular species and in several molecules. We report the first detection of HNCO in molecular outflows from massive YSOs. We discuss the CH3CN velocity gradient taking into account various scenarios: rotation, presence of multiple unresolved sources with different velocities, and outflow(s). Although other interpretations cannot be ruled out, we propose that the CH3CN emission might be affected by the outflows of the region. Higher angular observations are needed to discriminate between the different scenarios. The present observations, with the possible association of CH3CN with outflows in a few thousands AU around the YSOs' cluster, (i) question the choice of the tracer to probe rotating structures, and (ii) show the importance of the use of H2 images for detailed studies of kinematics.Comment: accepted for publication in A&

Mid-J CO emission from the Orion BN/KL explosive outflow

High spatial resolution low-J 12CO observations have shown that the wide-angle outflow seen in the Orion BN/KL region correlates with the famous H2 fingers. Recently, high-resolution large-scale mappings of mid- and higher-J CO emissions have been reported toward the Orion molecular cloud 1 core region using the APEX telescope. Therefore, it is of interest to investigate this outflow in the higher-J 12CO emission, which is likely excited by shocks. The observations were carried out using the dual-color heterodyne array CHAMP+ on the APEX telescope. The images of the Orion BN/KL region were obtained in the 12CO J=6-5 and J=7-6 transitions with angular resolutions of 8.6 and 7.4 arcsec, respectively. The results show a good agreement between our higher-J 12CO emission and SMA low-J 12CO data, which indicates that this wide-angle outflow in Orion BN/KL is likely the result of an explosive event that is related to the runaway objects from a dynamically decayed multiple system. From our observations, we estimate that the kinetic energy of this explosive outflow is about 1-2x10^47 erg. In addition, a scenario has been proposed where part of the outflow is decelerated and absorbed in the cloud to explain the lack of CO bullets in the southern part of BN/KL, which in turn induces the methanol masers seen in this region.Comment: 5 pages, 4 figure

Aplicación de la clasificación ATC al análisis de las prescripciones en DAMSU : I : los grupos de medicamentos que encabezan el ranking

Este es un estudio sobre utilización de medicamentos donde se analiza la evolución de la prescripción, en DAMSU de UNCuyo, de los 14 grupos terapéuticos (GT) de la clasificación ATC, durante 4 años consecutivos. Su objetivo fue determinar la prevalencia de las prescripciones en los 3 primeros niveles de la clasificación. Los datos fueron recolectados en los meses de abril, junio, setiembre y diciembre utilizando la metodología del DURG y procesados con un programa EPI INFO. Las comparaciones estadísticas fueron realizadas mediante la Prueba no paramétrica de los Signos. El ranking de GT fue constante pero el total de prescripciones disminuyó significativamente entre 2004 y 2007. Los GT del 1º nivel: S. Nervioso (N), S. cardiovascular (C), Digestivo y Metabolismo (A) y Músculo-esquelético (M), ocuparon, en orden decreciente, los cuatro primeros puestos del ranking durante los 4 años. De estos GT fueron analizados los subgrupos del 2º y 3º nivel. La prescripción de Psicolépticos + Psicoanalépticos superó a la de Analgésicos en el grupo N. En el grupo C los Agentes Antihipertensivos, y entre ellos los IECAs, encabezaron el ranking. Las vitaminas fueron las primeras en el GT A y el subgrupo de Antiinflamatorios y Antirreumáticos en el GT M. Se discuten estos resultados en función de la racionalidad de las prescripciones.This is a drug utilization research on the evolution of drug prescription in DAMSU of UNCuyo, during 4 consecutive years, comprising the 14 therapeutic groups (TG) of the ATC classification. The object was to determine the prescription prevalence in the 3 first levels of this classification. Data from April, June, September and December were collected according to the DURG methodology and processed by an EPI INFO program. Statistic comparisons were done with the nonparametric Signs Test. The TG ranking was constant but the total drug prescription lowered significantly between 2004 and 2007. Four TG at the first level were: Nervous S. (N), Cardiovascular S. (C), Digestive and Metabolism (A) and Muscle-Squeletal (M) shared in a decreasing order the first 4 places of the ranking in the 4 scored years. From these TG the 2º and 3º subgroups were analyzed. In the TG N the prescription of psychodrugs (Psycholeptics + Psychoanaleptics) was higher than that of Analgesics. In the TG C the Antihipertensive Agents, among which the ACEIs drugs are, did head the ranking. Vitamins were the first in the TG A and the subgroup of Anti-inflammatory and Antirheumatics headed the TG M. Results are discussed in terms of rationality of prescriptions.Fil: Sacchi, O. J.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de PatologíaFil: Kaiser, L. D.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de PatologíaFil: Riestra, E. C.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de PatologíaFil: Rodríguez, C. I.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de PatologíaFil: Zapata, M. P.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de PatologíaFil: Rodríguez Echandía, Eduardo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de Patologí

Consumo de drogas adictivas en alumnos de la UNCuyo, Mendoza, Argentina.

Este trabajo muestra los resultados de una encuesta realizada en 2010 sobre consumo de drogas adictivas en alumnos de 7 Facultades de la UNCUYO y los compara con los resultados obtenidos 12 años antes con una encuesta equivalente. La encuesta fue semiestructurada, con 17 preguntas, autocumplimentada, individual y anónima, con una muestra de 1108 alumnos de ambos sexos. De esa encuesta se utilizaron 7 preguntas específicas sobre drogas adictivas y una pregunta sobre consumo de medicamentos en general, con 46 opciones entre las que figuraban 10 denominaciones comerciales de benzodiacepinas, como drogas adictivas de prescripción. Para las comparaciones estadísticas se utilizó Chi cuadrado. El ranking de drogas utilizadas fue relativamente similar en 1998 y 2010 pero, exceptuando tabaco y “otras drogas" que se mantuvieron estables, el resto aumentó alrededor de 4 veces en el periodo. El 82,8% de los alumnos manifestó consumir alcohol (siempre + a veces); de 1 a 5 vasos semanales el 79%. En todas las Facultades, cerveza y Fernet encabezaron el ranquing de preferencias por bebidas alcohólicas. La prevalencia del consumo de tabaco en el total de la muestra se mantuvo constante en 1998 y 2010 (alrededor del 28%) pero el consumo entre Facultades fue variable y en Artes fue significativamente más elevado (42%). Siguen en el ranking marihuana con 10% de prevalencia, tranquilizantes con alrededor del 6% y cocaína con poco más del 1%. Finalmente “otras drogas" (Hachis, LSD, extasis, anabólicos, anfetaminas, “hongos") representaron solamente un 3% de prevalencia. Artes y Ciencias Políticas mostraron las mayores prevalencias de consumo y Derecho e Ingeniería las menores. Esto indica implementar acciones preventivas y correctivas particulares para cada Facultad.This is a research on addictive drugs use by students of 7 schools of the UNCUYO. The results of an inquire made in 2010 are compared with the results of an equivalent inquire made 12 years before. The inquire was partially structured and consists of 17 questions, autographic, individual and anonymous, and was applied to a 1108 students sample. The inquire was devoted to ascertain use and knowledge about prescription drugs use and comprised 7 specific questions on addictive drugs use as well as a prescription drugs question with 46 options comprising 10 commercial names of benzodiazepines as addictive prescription drugs. Chi square was used for statistic comparisons. The ranking of addictive drugs use was quite similar in the 1998 and the 2010 inquires. However, excepting tobacco and “other drugs" which prevalence remained constant, the rest of consigned drugs prevalence increased about 4 folds in this period. The prevalence of alcohol users was about 83% (always + some-times users) and 79% said to drank 1 to 5 glasses a week. Bear and Fernet headed the ranking of alcoholic drinks preference. The prevalence of tobacco use in the whole student sample was constant in both inquires (about 28%) but the amongschools use was variable; in Arts was significantly higher than that (42%). Followed in the ranking marihuana with a 10% prevalence, tranquilizers (about 6%) and cocaine with a little more than 1%. Finally, “other drugs" (Hachis, LSD, extasis, anabolics, anfetamines and funguses) represented all together a 3% prevalence. Arts and Politic Sciences Schools showed the highest prevalence in addictive drugs use and Law and Engineery the lowest. The results point to planning particular preventing and corrective actions for each School.Fil: Kaiser, L. D.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Rodríguez, C.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Zapata, M. P.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Sacchi, O. J.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Riestra, E. C.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Aranda, L.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Rodríguez Echandía, Eduardo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología

A bright radio HH object with large proper motions in the massive star-forming region W75N

We analyze radio continuum and line observations from the archives of the Very Large Array, as well as X-ray observations from the \emph{Chandra} archive of the region of massive star formation W75N. Five radio continuum sources are detected: VLA 1, VLA 2, VLA 3, Bc, and VLA 4. VLA 3 appears to be a radio jet; we detect J=1-0, v=0 SiO emission towards it, probably tracing the inner parts of a molecular outflow. The radio continuum source Bc, previously believed to be tracing an independent star, is found to exhibit important changes in total flux density, morphology, and position. These results suggest that source Bc is actually a radio Herbig-Haro object, one of the brightest known, powered by the VLA~3 jet source. VLA 4 is a new radio continuum component, located a few arcsec to the south of the group of previously known radio sources. Strong and broad (1,1) and (2,2) ammonia emission is detected from the region containing the radio sources VLA~1, VLA~2, and VLA~3. Finally, the 2-10 keV emission seen in the \emph{Chandra}/ACIS image shows two regions that could be the termination shocks of the outflows from the multiple sources observed in W75N.Comment: 26 pages, 7 figure