Proper Motion of H2O Masers in IRAS 20050+2720 MMS1: An AU Scale Jet Associated with An Intermediate-Mass Class 0 Source

We conducted a 4 epoch 3 month VLBA proper motion study of H$_2$O masers toward an intermediate-mass class 0 source IRAS 20050+2720 MMS1 (d=700 pc). From milli-arcsecond (mas) resolution VLBA images, we found two groups of H2O maser spots at the center of the submillimeter core of MMS1. One group consists of more than $\sim 50$ intense maser spots; the other group consisting of several weaker maser spots is located at 18 AU south-west of the intense group. Distribution of the maser spots in the intense group shows an arc-shaped structure which includes the maser spots that showed a clear velocity gradient. The spatial and velocity structures of the maser spots in the arc-shape did not significantly change through the 4 epochs. Furthermore, we found a relative proper motion between the two groups. Their projected separation increased by 1.13+/-0.11 mas over the 4 epochs along a line connecting them. The spatial and velocity structures of the intense group and the relative proper motions strongly suggest that the maser emission is associated with a protostellar jet. Comparing the observed LSR velocities with calculated radial velocities from a simple biconical jet model, we conclude that the most of the maser emission are likely to be associated with an accelerating biconical jet which has large opening angle. The large opening angle of the jet traced by the masers would support the hypothesis that poor jet collimation is an inherent property of luminous (proto)stars.Comment: 14 pages, 10 figures, Fig.3 was downsized significantly. accepted for publication in A&

First results from a VLBA proper motion survey of H2O masers in low-mass YSOs: the Serpens core and RNO15-FIR

This article reports first results of a long-term observational program aimed to study the earliest evolution of jet/disk systems in low-mass YSOs by means of VLBI observations of the 22.2 GHz water masers. We report here data for the cluster of low-mass YSOs in the Serpens molecular core and for the single object RNO~15-FIR. Towards Serpens SMM1, the most luminous sub-mm source of the Serpens cluster, the water maser emission comes from two small (< 5 AU in size) clusters of features separated by ~25 AU, having line of sight velocities strongly red-shifted (by more than 10 km/s) with respect to the LSR velocity of the molecular cloud. The two maser clusters are oriented on the sky along a direction that is approximately perpendicular to the axis of the radio continuum jet observed with the VLA towards SMM1. The spatial and velocity distribution of the maser features lead us to favor the interpretation that the maser emission is excited by interaction of the receding lobe of the jet with dense gas in the accretion disk surrounding the YSO in SMM1. Towards RNO~15-FIR, the few detected maser features have both positions and (absolute) velocities aligned along a direction that is parallel to the axis of the molecular outflow observed on much larger angular scales. In this case the maser emission likely emerges from dense, shocked molecular clumps displaced along the axis of the jet emerging from the YSO. The protostar in Serpens SMM1 is more massive than the one in RNO~15-FIR. We discuss the case where a high mass ejection rate can generate jets sufficiently powerful to sweep away from their course the densest portions of circumstellar gas. In this case, the excitation conditions for water masers might preferably occur at the interface between the jet and the accretion disk, rather than along the jet axis.Comment: 18 pages (postscript format); 9 figures; to be published into Astronomy & Astrophysics, Main Journa

SARS-CoV-2 vaccines: Inactivation by gamma irradiation for T and B cell immunity

Despite accumulating preclinical data demonstrating a crucial role of cytotoxic T cell immunity during viral infections, ongoing efforts on developing COVID-19 vaccines are mostly focused on antibodies. In this commentary article, we discuss potential benefits of cytotoxic T cells in providing long-term protection against COVID-19. Further, we propose that gamma-ray irradiation, which is a previously tested inactivation method, may be utilized to prepare an experimental COVID-19 vaccine that can provide balanced immunity involving both B and T cells

A case that underwent bilateral video-assisted thoracoscopic surgical biopsy combined with left pneumonectomy : case report

No Abstract Available A case that underwent bilateral video-assisted thoracoscopic surgical (VATS) biopsy combined with pneumonectomy is presented. The patient developed hypoxia during the contralateral VATS biopsy. His hypoxia was treated with positive expiratory pressure (PEEP) to the dependent lung and apneic oxygen insufflation to the operative lung. The cause was probably airway obstruction due to his intraluminal tumor plus secretions. This case report contains interesting aspects in the anesthetic management. Key words: Video-assisted thoracoscopic surgical (VATS) biopsy, Anesthesia, Staging Southern African Journal of Anaesthesia & Analgesia Vol.11(2) 2005: 75-7

Optimal Layout Design for Agricultural Facility Using Simulated Annealing

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): T. Satake, O. Sataka, Y. Ohta, and T. Furuya. Optimal Layout Design for Agricultural Facility Using Simulated Annealing. Vol. V. May 2003