207 research outputs found
The ALMA Early Science View of FUor/EXor objects. III. The Slow and Wide Outflow of V883 Ori
We present Atacama Large Millimeter/ sub-millimeter Array (ALMA) observations
of V883 Ori, an FU Ori object. We describe the molecular outflow and envelope
of the system based on the CO and CO emissions, which together
trace a bipolar molecular outflow. The CO emission traces the rotational
motion of the circumstellar disk. From the CO blue-shifted emission, we
estimate a wide opening angle of 150 for the outflow
cavities. Also, we find that the outflow is very slow (characteristic velocity
of only 0.65 km~s), which is unique for an FU Ori object. We calculate
the kinematic properties of the outflow in the standard manner using the
CO and CO emissions. In addition, we present a P Cygni profile
observed in the high-resolution optical spectrum, evidence of a wind driven by
the accretion and being the cause for the particular morphology of the
outflows. We discuss the implications of our findings and the rise of these
slow outflows during and/or after the formation of a rotationally supported
disk.Comment: 12 pages, 7 figures, 2 tables. Accepte
Limits on the Electromagnetic and Weak Dipole Moments of the Tau-Lepton in E_6 Superstring Models
We obtain limits on the electromagnetic and weak dipole moments of the
tau-lepton in the framework of a Left-Right symmetric model (LRSM) and a class
of inspired models with an additional neutral vector boson .
Using as an input the data obtained by the L3 and OPAL Collaborations for the
reaction , we get a stringent limit on the LRSM
mixing angle , , which in
turn induces bounds on the tau weak dipole moments which are consistent with
the bounds obtained recently by the DELPHI and ALEPH Collaborations from the
reaction . We also get similar bounds for the weak
dipole moments of the tau lepton in the framework of superstring models.Comment: 18 pages, 5 figure
Performance, behaviour and meat quality of beef heifers fed concentrate and straw offered as total mixed ration or free-choice
Eighteen Simmental heifers were fed concentrate and barley straw offered as a total mixed ration (TMR) or separately as a free choice (FCH) to compare performance, behaviour, and meat quality. The heifers were assigned to treatments in a randomized complete block design. Animals were allotted to roofed pens with 3 animals per pen, and 3 pens per treatment. Intake of concentrate, average daily gain, and gain to feed ratio were not different between diets, being on average 7.6 kg/day, 1.38 kg/day and 0.18 kg/kg, respectively. Straw intake was greater in TMR than in FCH treatment (0.7 vs 0.3 kg/day, respectively; p<0.001). Crude protein intake, neutral detergent fibre intake and water consumption did not differ between treatments. Time spent eating was longer in FCH than in TMR (p=0.001), whereas time spent ruminating and total chewing time were longer (p<0.01) in TMR than in FCH. The number of displacements resulting from competition for feed in the main feeder in TMR treatment tended to be greater than in FCH treatment. There were no differences in the carcass characteristics and quality of meat of animals assigned to the different feeding methods, but the percentage of 18:2 n-6 was higher in FCH treatment. In summary, these results suggest that the use of TMR as a feeding method in beef cattle fed high concentrate diets did not affect performance and increased time spent ruminating with a potential decrease of ruminal acidosis incidence
First Report of an OXA-23 Carbapenemase-Producing Acinetobacter baumannii Clinical Isolate Related to Tn2006 in Spain
A carbapenem-resistant Acinetobacter baumannii clinical isolate belonging to European clone II and sequence type 2 was recov-ered from a patient in the Son Espases hospital in Mallorca, Spain. Genetic analysis showed the presence of the bla OXA-23 gene in association with the widely disseminated transposon Tn2006. This is the first reported identification of A. baumannii carrying bla OXA-23 in Spain
Usefulness of clinical scores to improve prediction of significant coronary heart disease after conventional treadmill exercise testing
ANTECEDENTES: en el último consenso de la AHA/ACC se recomiendan puntajes clínicos para mejorar la sensibilidad (68%) y la especificidad (77%) de la prueba de esfuerzo, método diagnóstico de primera línea en el tratamiento de la enfermedad coronaria (una de las principales causas de morbimortalidad en Colombia y el mundo). Sin embargo, son pocas las instituciones del país que los utilizan y son difíciles de aplicar en poblaciones diferentes a aquellas para las cuales fueron desarrollados, haciéndose necesario realizar un estudio que valore su desempeño en nuestro medio.
MATERIALES Y MÉTODOS: se escogieron las escalas de Morise y Duke para evaluar por qué han sido validadas en varias poblaciones y fueron citadas en el consenso de la AHA/ACC. Los puntajes de Morise y Duke clasificaron a los pacientes en probabilidad baja, intermedia o alta para enfermedad coronaria.
OBJETIVOS PRIMARIOS: validar las escalas de predicción para enfermedad coronaria y determinar el mejor punto de corte para cada escala en un tiempo de seguimiento de un año.
OBJETIVOS SECUNDARIOS: determinar un desenlace compuesto por infarto agudo del miocardio, muerte cardiaca, angina que requiere hospitalización, obstrucción coronaria mayor a 50% y/o angioplastia e implante de stent. Determinar el mejor punto de corte mediante curvas de ROC.
CRITERIOS DE INCLUSIÓN: pacientes mayores de 18 años de edad, con sospecha de enfermedad coronaria.
CRITERIOS DE EXCLUSIÓN: pacientes embarazadas, con enfermedad coronaria documentada, electrocardiograma no interpretable, incapacidad o contraindicación para realizar prueba de esfuerzo por cualquier motivo, depresión del segmento ST menor a 1 mm en el electrocardiograma de base, imposibilidad de realizar seguimiento, y datos incompletos que impidieran el cálculo de las escalas.
ANÁLISIS ESTADÍSTICO: la muestra se calculó utilizando error alfa menor de 0,05, error beta menor de 0,20 (poder de 80%), probabilidad de clasificación correcta 0,4, nivel de kappa para la
hipótesis nula 0,85 y nivel de kappa para la hipótesis alterna 0,7. Se utilizó el programa Tamaño de la
Muestra (TaMaMu), versión 1,0, se requirieron 101 pacientes.
RESULTADOS: se reclutaron 127 pacientes y se excluyeron 9; 2 por pruebas de esfuerzo submáximas
y 7 por no ser posible el seguimiento, y se analizaron 118. El seguimiento promedio fue de 343 días (1-
564. Edad media: 59 años (29-83). Mujeres: 53% (63) y hombres: 47% (55). Edad media de 59 y de 57
años, respectivamente. Otras características: tabaquismo: 47% (55), dislipidemia: 68% (80), índice de
masa corporal mayor a 27,5: 18% (45) y diabetes mellitus: 16% (19). La escala de Morise clasificó 36%
(43) en bajo riesgo, 52% (61) en riesgo intermedio y 12% (14) en riesgo alto. Según Duke los resultados
fueron 53% (63), 41% (48) y 6% (7) respectivamente. Al interpretar la prueba de esfuerzo aislada, los
cardiólogos clasificaron a los pacientes así: 81% (95) negativas, 8% (10) sugestivas y 11% (14) positivas. El punto o desenlace final compuesto se presentó en 11% (14 pacientes). Al comparar a los pacientes con desenlace y sin éste, los primeros se clasificaban con más frecuencia como de alta probabilidad que aquellos que no, con diferencias estadísticamente significativas (Morise: p=0,0002 y Duke: 0,0005). En la escala de Morise con punto de corte de 48, se logró sensibilidad de 92% y especificidad de 68%. En Duke, con punto de corte de 38, fue de 100% y 31%.
DISCUSIÓN: la concordancia para Morise es mejor que para los demás métodos evaluados. Adicionar los puntajes clínicos a la interpretación de la prueba de esfuerzo mejora las características operativas de la misma sin aumentar los costos, y se logra un ahorro de 10% a 18%.
CONCLUSIONES: los puntajes clínicos aumentan la sensibilidad y la especificidad, por lo cual se deberían utilizar de manera rutinaria para el informe de una prueba de esfuerzo convencional. Sin embargo, se hace necesario buscar soluciones que mejoren aún más dicho desempeño.Q4Artículo original207-214BACKGROUND: in the last AHA/ACC expert consensus document, clinical scores to improve sensitivity (68%) and specificity (77% of the exercise testing, diagnostic method considered a first line diagnostic method for coronary heart disease treatment (one of the main causes of mortality in Colombia and worldwide), are recommended. Nevertheless, few institutions in our country use them and they are difficult to apply in populations different to the ones for which they were developed. For this reason, a study to assess its performance in our environment, is needed
MATERIALS AND METHODS: Morise and Duke treadmill scores were chosen to assess the reason for its validation in several populations, and were mentioned in the AHA/ACC consensus. The Morise and Duke scores classified patients in at low, middle and high risk for coronary heart disease.
PRIMARY OBJECTIVES: validate the prediction scales for coronary heart disease and determine the best cutoff value for each score in a one year follow-up.
SECONDARY OBJECTIVES: determine the composite endpoint for acute myocardial infarction, cardiac death, angina requiring hospitalization, coronary obstruction >50% and/or angioplasty and stent implantation. Determine the best cutoff point through the ROC curves.
INCLUSION CRITERIA: patients >18 years old with suspected coronary heart disease.
EXCLUSION CRITERIA: pregnant women with documented coronary heart disease, uninterpretable EKG, incapacity or contraindication for performing exercise stress test for any reason, ST depression < 1 mm in basal EKG, follow-up impossibility and incomplete data that might hinder the score calculation.
STATISTICAL ANALYSIS: the sample was calculated using alpha error < 0.05, beta error < 0.20 (power 80%), correct classification probability 0.4, kappa level for null hypothesis 0.85 and kappa level for alternate hypothesis 0,7. The Sample Size Program version 1.0 was used. 101 patients were required.
RESULTS: 127 patients were enrolled and 9 were excluded: 2 because of submaximal exercise testings and 7 because the follow up was impossible. 118 patients were analyzed. Mean follow-up was 343 days (1 - 564). Mean age was 59 years (29 - 83). Women: 53% (63) and men: 47% (55). Mean age 59 and 57 years respectively. Other characteristics: cigarette smoking: 47% (55), dyslipidemia: 68% (80), body mass index > 27,5: 18% (45) and diabetes mellitus: 16% (19). Morise score classified 36% (43) patients at low risk, 52% (61) at intermediate risk and 12% (14) at high risk. According to Duke the results were 53% (63), 41% (48) and 6% (7) respectively. When interpreting an isolated exercise testing, cardiologists classified patients: 81% (95) negative, 8% (10) suggestive and 11% (14) positive. The composite endpoint appeared in 11% (14 patients). When comparing patients with and without outcomes, the first ones classified more frequently as having higher probability than those that had not, with statistically significant differences (Morise: p = 0,0002 and Duke: 0,0005). In the Morise score with cutoff value 48, 92% sensitivity and 68% specificity was achieved. In Duke, with cutoff value 38, it was 100% and 31% respectively.
DISCUSSION: concordance for Morise is better than for the other evaluated methods. The addition of clinical scores to the exercise testing interpretation improves its operative characteristics without any cost increment, achieving savings of 10% to 18%.
CONCLUSIONS: clinical scores increase sensitivity and specificity, and for this reason they should be used as routine in the conventional exercise testing report. Nevertheless, it is necessary to look for solutions to improve its performance even further
Alma Survey Of Circumstellar Disks In The Young Stellar Cluster IC 348
We present a 1.3 mm continuum survey of the young (2-3 Myr) stellar cluster
IC 348, which lies at a distance of 310 pc, and is dominated by low-mass stars
(M 0.1-0.6 M). We observed 136 Class II sources
(disks that are optically thick in the infrared) at 0.8 (200 au) resolution
with a 3 sensitivity of 0.45 mJy (M 1.3
M). We detect 40 of the targets and construct a mm-continuum
luminosity function. We compare the disk mass distribution in IC 348 to those
of younger and older regions, taking into account the dependence on stellar
mass. We find a clear evolution in disk masses from 1 to 5-10 Myr. The disk
masses in IC 348 are significantly lower than those in Taurus (1-3 Myr) and
Lupus (1-3 Myr), similar to those of Chamaleon~I, (2-3 Myr) and Ori
(3-5 Myr) and significantly higher than in Upper Scorpius (510 Myr). About
20 disks in our sample (5 of the cluster members) have estimated
masses (dust gas) 1 M and hence might be the precursors of
giant planets in the cluster. Some of the most massive disks include transition
objects with inner opacity holes based on their infrared SEDs. From a stacking
analysis of the 96 non-detections, we find that these disks have a typical dust
mass of just 0.4 M, even though the vast majority of
their infrared SEDs remain optically thick and show little signs of evolution.
Such low-mass disks may be the precursors of the small rocky planets found by
\emph{Kepler} around M-type stars.Comment: 19 pages, 12 figure
ALMA observations of Elias 2–24: a protoplanetary disk with multiple gaps in the Ophiuchus molecular cloud
We present ALMA 1.3 mm continuum observations at 0. 2 (25 au) resolution of Elias 2–24, one of the largest and brightest protoplanetary disks in the Ophiuchus Molecular Cloud, and we report the presence of three partially resolved concentric gaps located at ∼20, 52, and 87 au from the star. We perform radiative transfer modeling of the disk to constrain its surface density and temperature radial profile and place the disk structure in the context of mechanisms capable of forming narrow gaps such as condensation fronts and dynamical clearing by actively forming planets. In particular, we estimate the disk temperature at the locations of the gaps to be 23, 15, and 12 K (at 20, 52, and 87 au, respectively), very close to the expected snowlines of CO (23–28 K) and N2 (12–15 K). Similarly, by assuming that the widths of the gaps correspond to 4–8× the Hill radii of forming planets (as suggested by numerical simulations), we estimate planet masses in the range of 0.2 1.5 – MJup, 1.0 8.0 – MJup, and 0.02 0.15 – MJup for the inner, middle, and outer gap, respectively. Given the surface density profile of the disk, the amount of “missing mass” at the location of each one of these gaps (between 4 and 20 MJup) is more than sufficient to account for the formation of such planets.Fil: Cieza, Lucas A.. Universidad Diego Portales; ChileFil: Casassus, Simon. Universidad de Chile; ChileFil: Pérez, Sebastian. Universidad de Chile; ChileFil: Hales, Antonio. Alma Observatory; ChileFil: Cárcamo, Miguel. Universidad de Chile; ChileFil: Ansdell, Megan. University of California at Berkeley; Estados UnidosFil: Avenhaus, Henning. Universitat Zurich; SuizaFil: Bayo, Amelia. Universidad de Valparaiso; ChileFil: Bertrang, Gesa H.-M.. Universidad Diego Portales; ChileFil: Cánovas, Hector. Agencia Espacial Europea; EspañaFil: Christiaens, Valentin. Universidad de Chile; ChileFil: Dent, William. Alma Observatory; ChileFil: Ferrero, Gabriel. 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: Gamen, Roberto Claudio. 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: Olofsson, Johan. Universidad de Valparaiso; ChileFil: Orcajo, Santiago. 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: Osses, Axel. Universidad de Chile; ChileFil: Peña Ramirez, Karla. Universidad de Antofagasta; ChileFil: Principe, David. Massachusetts Institute of Technology; Estados UnidosFil: Ruíz Rodríguez, Dary. Rochester Institute Of Technology; Estados UnidosFil: Schreiber, Matthias R.. Universidad de Valparaiso; ChileFil: Plas, Gerrit van der. Univ. Grenoble Alpes; SuizaFil: Williams, Jonathan P.. Institute For Astronomy, University Of Hawaii; Estados UnidosFil: Zurlo, Alice. Universidad Diego Portales; Chil
The Ophiuchus DIsc Survey Employing ALMA (ODISEA). II. The effect of stellar multiplicity on disc properties
We present Adaptive Optics (AO) near infrared (NIR) observations using
VLT/NACO and Keck/NIRC2 of ODISEA targets. ODISEA is an ALMA survey of the
entire population of circumstellar discs in the Ophiuchus molecular cloud. From
the whole sample of ODISEA we select all the discs that are not already
observed in the NIR with AO and that are observable with NACO or NIRC2. The
NIR-ODISEA survey consists of 147 stars observed in NIR AO imaging for the
first time, as well as revisiting almost all the binary systems of Ophiuchus
present in the literature (20 out of 21). In total, we detect 20 new binary
systems and one triple system. For each of them we calculate the projected
separation and position angle of the companion, as well as their NIR and
millimeter flux ratios. From the NIR contrast we derived the masses of the
secondaries, finding that 9 of them are in the sub-stellar regime (30-50
\MJup). Discs in multiple systems reach a maximum total dust mass of 50
M, while discs in single stars can reach a dust mass of 200
M. Discs with masses above 10 M are found only around
binaries with projected separations larger than 110 au. The maximum disc
size is also larger around single star than binaries. However, since most discs
in Ophiuchus are very small and low-mass, the effect of visual binaries is
relatively weak in the general disc population.Comment: 13 pages, 13 figures, 4 tables. Published in MNRA
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