An ASCA Study of the W51 Complex

We present the analysis of ASCA archival data from the Galactic source W51. The ASCA spectra show that the soft (kT<= 2.5 keV) X-rays are of thermal origin and are compatible with W51C being a single, isothermal (kT~0.3 keV) supernova remnant at the far-side of the Sagittarius arm. The ASCA images reveal hard (kT>=2.5 keV) X-ray sources which were not seen in previous X-ray observations. Some of these sources are coincident with massive star-forming regions and the spectra are used to derive X-ray parameters. By comparing the X-ray absorbing column density with atomic hydrogen column density, we infer the location of star-forming regions relative to molecular clouds. There are unidentified hard X-ray sources superposed on the supernova remnant and we discuss the possibility of their association.Comment: 13 pages, 11 figures, to be published in Astronomical Journa

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM