3,974 research outputs found
Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26
We performed a multi-wavelength study toward the filamentary cloud
G47.06+0.26 to investigate the gas kinematics and star formation. We present
the 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) observations of G47.06+0.26
obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to
investigate the detailed kinematics of the filament. The 12CO (J=1-0) and 13CO
(J=1-0) emission of G47.06+0.26 appear to show a filamentary structure. The
filament extends about 45 arcmin (58.1 pc) along the east-west direction. The
mean width is about 6.8 pc, as traced by the 13CO (J=1-0) emission. G47.06+0.26
has a linear mass density of about 361.5 Msun/pc. The external pressure (due to
neighboring bubbles and H II regions) may help preventing the filament from
dispersing under the effects of turbulence. From the velocity-field map, we
discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam
Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in
G47.06+0.26, that appear to these sources have sufficient mass to form massive
stars. We obtained that the clump formation efficiency (CFE) is about 18% in
the filament. Four infrared bubbles were found to be located in, and adjacent
to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure.
CO molecular gas adjacent to N98 also shows a very intense emission. H II
regions associated with infrared bubbles can inject the energy to surrounding
gas. We calculated the kinetic energy, ionization energy, and thermal energy of
two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some
Class I sources with an age of about 100000 yr, which are clustered along the
filament. The feedback from the H II regions may cause the formation of a new
generation of stars in filament G47.06+0.26.Comment: 10 pages, 11 figures, accepted for publication in A&
Age as a risk factor for acute mountain sickness upon rapid ascent to 3,700 m among young adult Chinese men.
BackgroundThe aim of this study was to explore the relationship between age and acute mountain sickness (AMS) when subjects are exposed suddenly to high altitude.MethodsA total of 856 young adult men were recruited. Before and after acute altitude exposure, the Athens Insomnia Scale score (AISS) was used to evaluate the subjective sleep quality of subjects. AMS was assessed using the Lake Louise scoring system. Heart rate (HR) and arterial oxygen saturation (SaO2) were measured.ResultsResults showed that, at 500 m, AISS and insomnia prevalence were higher in older individuals. After acute exposure to altitude, the HR, AISS, and insomnia prevalence increased sharply, and the increase in older individuals was more marked. The opposite trend was observed for SaO2. At 3,700 m, the prevalence of AMS increased with age, as did severe AMS, and AMS symptoms (except gastrointestinal symptoms). Multivariate logistic regression analysis showed that age was a risk factor for AMS (adjusted odds ratio [OR] 1.07, 95% confidence interval [CI] 1.01-1.13, P<0.05), as well as AISS (adjusted OR 1.39, 95% CI 1.28-1.51, P<0.001).ConclusionThe present study is the first to demonstrate that older age is an independent risk factor for AMS upon rapid ascent to high altitude among young adult Chinese men, and pre-existing poor subjective sleep quality may be a contributor to increased AMS prevalence in older subjects
Magnetic surface on nonmagnetic bulk of electride Hf2S
Recent experiment reported the self-passivated electride Hf2S with excellent
stability and continuous electrocatalytic ability [S. H. Kang et al., Sci. Adv.
6, eaba7416 (2020)]. Starting from its 2H-type layered structure, we have
studied the electronic, magnetic, and transport properties of the electride
Hf2S in the monolayer and multilayer forms by combining first-principles
electronic structure calculations and Kubo formula approach. Our calculations
indicate that these thin films of Hf2S electride are both dynamically and
thermodynamically stable. Astonishingly, the calculations further show that the
outmost Hf atoms and the surface electron gas of the Hf2S multilayers are spin
polarized, while the inner Hf atoms and the electron gas in the interlayer
regions remain nonmagnetic. Due to the magnetic surface, the multilayer Hf2S
exhibits many unusual transport properties such as the surface anomalous Hall
effect and the electric-field-induced layer Hall effect. Our theoretical
predictions on Hf2S call for future experimental verification.Comment: 5 pages, 5 figures, 34 reference
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