A Double-Jet System in the G31.41+0.31 Hot Molecular Core

This work presents a detailed study of the gas kinematics towards the "Hot Molecular Core" (HMC) G31.41+0.31 via multi-epoch VLBI observations of the H2O 22 GHz and CH3OH 6.7 GHz masers, and single-epoch VLBI of the OH 1.6 GHz masers. Water masers present a symmetric spatial distribution with respect to the HMC center, where two nearby (0.2" apart), compact, VLA sources (labeled "A" and "B") are previously detected. The spatial distribution of a first group of water masers, named "J1", is well fit with an elliptical profile, and the maser proper motions mainly diverge from the ellipse center, with average speed of 36 km s-1. These findings strongly suggest that the "J1" water maser group traces the heads of a young (dynamical time of 1.3 10^3 yr), powerful (momentum rate of ~0.2 M_sun yr-1 km s-1), collimated (semi-opening angle ~10 deg) jet emerging from a MYSO located close (within 0.15") to the VLA source "B". Most of the water features not belonging to "J1" present an elongated (about 2" in size), NE--SW oriented (PA = 70 deg), S-shape distribution, which we denote with the label "J2". The elongated distribution of the "J2" group and the direction of motion, approximately parallel to the direction of elongation, of most "J2" water masers suggests the presence of another collimated outflow, emitted from a MYSO near the VLA source "A". The orientation of the "J2" jet agrees well with that (PA = 68 deg) of the well-defined V_LSR gradient across the HMC revealed by previous interferometric, thermal line observations. Furthermore, the "J2" jet is powerful enough to sustain the large momentum rate, 0.3 M_sun yr-1 km s-1, estimated assuming that the V_LSR gradient represents a collimated outflow. These two facts lead us to favour the interpretation of the V_LSR gradient across the G31.41+0.31 HMC in terms of a compact and collimated outflow.Comment: 23 pages, 7 figures, accepted for publication in Astronomy & Astrophysic

Deep Learning Based on Orthogonal Approximate Message Passing for CP-Free OFDM

Channel estimation and signal detection are very challenging for an orthogonal frequency division multiplexing (OFDM) system without cyclic prefix (CP). In this article, deep learning based on orthogonal approximate message passing (DL-OAMP) is used to address these problems. The DL-OAMP receiver includes a channel estimation neural network (CE-Net) and a signal detection neural network based on OAMP, called OAMP-Net. The CE-Net is initialized by the least square channel estimation algorithm and refined by minimum mean-squared error (MMSE) neural network. The OAMP-Net is established by unfolding the iterative OAMP algorithm and adding some trainable parameters to improve the detection performance. The DL-OAMP receiver is with low complexity and can estimate time-varying channels with only a single training. Simulation results demonstrate that the bit-error rate (BER) of the proposed scheme is lower than those of competitive algorithms for high-order modulation.Comment: 5 pages, 4 figures, updated manuscript, International Conference on Acoustics, Speech and Signal Processing (ICASSP 2019). arXiv admin note: substantial text overlap with arXiv:1903.0476

A multiwavelength study of massive star-forming region IRAS 22506+5944

We present a multi-line study of the massive star-forming region IRAS 22506+5944. A new 6.7 GHz methanol maser was detected. 12CO, 13CO, C18O and HCO+ J = 1-0 transition observations reveal a star formation complex consisting mainly of two cores. The dominant core has a mass of more than 200 solar mass, while another one only about 35 solar mass. Both cores are obviously at different evolutionary stages. A 12CO energetic bipolar outflow was detected with an outflow mass of about 15 solar mass.Comment: 9 pages, 4 figure

Localized Malignant Myxoid Anaplastic Mesothelioma of the Pericardium

Primary malignant mesothelioma of the pericardium is a rare cardiac neoplasm. Most are diffuse and have poor prognosis with median survival of six months. In the paper, we describe a young male patient having no exposure history of asbestos with localized malignant myxoid mesothelioma of the pericardium. The tumor displayed significant myxoid change in stroma, and anaplastic cytology, including pleomorphy, poor cohesion, prominent nuclei, with high mitoses, which led to difficulty in diagnosis. The tumor showed typical immunohistochemical phenotypes of mesothelioma, positive for WT-1, calretinin and CK5/6. Ki-67 labeling index was about 50% in general and nearly 80% in the most active areas. The patient showed better outcome. The report suggests the diagnosis of myxoid mesothelioma is supposed to rely on clinical data, and immunohistochemistry is assumed to be for differentiation