908 research outputs found
The catalogues and mid-infrared environment of Interstellar OH Masers
Data for a number of OH maser lines have been collected from surveys. The
posi- tions are compared to recent mid-infrared (MIR) surveys such as
Spitzer-GLIMPSE and WISE, restricting the comparison to point sources. The
colors and intensities of the IR sources are compared. There are many 18 cm OH
masers, but far fewer in lines arising from higher energy levels. We also make
a comparison with the 5 cm Class II methanol masers. We have divided the
results into 3 subsamples: those associated with OH masers only, those
associated with OH masers and Class II methanol masers, and those only
associated with Class II methanol masers. There are no obvious dif- ferences in
the color-color or color-magnitude results for the GLIMPSE point sources.
However, according to the results from the WISE 22 {\mu}m survey, the sources
associ- ated with OH masers are brighter than those associated with methanol
masers. We interpret the presence of OH and methanol masers mark the locations
of regions where stars are forming. The OH masers are located on the borders of
sharp features found in the IR. These are referred to as bubbles. If the OH
masers mark the positions of protostars, the result provides indirect evidence
for triggered star formation caused by the expansion of the bubbles.Comment: 23 pages (11 pages online only), 12 figures, Accepted. Monthly
Notices of the Royal Astronomical Society,201
Transformer-based models and hardware acceleration analysis in autonomous driving: A survey
Transformer architectures have exhibited promising performance in various
autonomous driving applications in recent years. On the other hand, its
dedicated hardware acceleration on portable computational platforms has become
the next critical step for practical deployment in real autonomous vehicles.
This survey paper provides a comprehensive overview, benchmark, and analysis of
Transformer-based models specifically tailored for autonomous driving tasks
such as lane detection, segmentation, tracking, planning, and decision-making.
We review different architectures for organizing Transformer inputs and
outputs, such as encoder-decoder and encoder-only structures, and explore their
respective advantages and disadvantages. Furthermore, we discuss
Transformer-related operators and their hardware acceleration schemes in depth,
taking into account key factors such as quantization and runtime. We
specifically illustrate the operator level comparison between layers from
convolutional neural network, Swin-Transformer, and Transformer with 4D
encoder. The paper also highlights the challenges, trends, and current insights
in Transformer-based models, addressing their hardware deployment and
acceleration issues within the context of long-term autonomous driving
applications
A spectral line survey of IRC +10216 between 13.3 and 18.5 GHz
A spectral line survey of IRC +10216 between 13.3 and 18.5 GHz is carried out
using the Shanghai Tian Ma 65 m Radio Telescope (TMRT-65m) with a sensitivity
of < 7 mK. Thirty-five spectral lines of 12 different molecules and radicals
are detected in total. Except for SiS, the detected molecules are all
carbon-chain molecules, including HC3N, HC5N, HC7N, HC9N, C6H, C6H-, C8H, SiC2,
SiC4, c-C3H2 and l-C5H. The presence of rich carbon-bearing molecules is
consistent with the identity of IRC +10216 as a carbon-rich AGB star. The
excitation temperatures and column densities of the observed species are
derived by assuming a local thermodynamic equilibrium and homogeneous
conditions.Comment: This is the authors' version of the manuscript; 16 pages, 5 figures,
6 tables; Accepted for publication in A&A 8/17/201
Detection of a methanol megamaser in a major-merger galaxy
We have detected emission from both the 4_{-1}-3_{0} E (36.2~GHz) class I and
7_{-2}-8_{-1} E (37.7~GHz) class II methanol transitions towards the centre of
the closest ultra-luminous infrared galaxy Arp 220. The emission in both the
methanol transitions show narrow spectral features and have luminosities
approximately 8 orders of magnitude stronger than that observed from typical
class I methanol masers observed in Galactic star formation regions. The
emission is also orders of magnitude stronger than the expected intensity of
thermal emission from these transitions and based on these findings we suggest
that the emission from the two transitions are masers. These observations
provides the first detection of a methanol megamaser in the 36.2 and 37.7 GHz
transitions and represents only the second detection of a methanol megamaser,
following the recent report of an 84 GHz methanol megamaser in NGC1068. We find
the methanol megamasers are significantly offset from the nuclear region and
arise towards regions where there is Ha emission, suggesting that it is
associated with starburst activity. The high degree of correlation between the
spatial distribution of the 36.2 GHz methanol and X-ray plume emission suggests
that the production of strong extragalactic class I methanol masers is related
to galactic outflow driven shocks and perhaps cosmic rays. In contrast to OH
and H2O megamasers which originate close to the nucleus, methanol megamasers
provide a new probe of feedback (e.g. outflows) processes on larger-scales and
of star formation beyond the circumnuclear starburst regions of active
galaxies.Comment: Accepted for publication in ApJ
The Effect of Operating in Many Realities on Memory: An Experiment on Memory Recognition in Extended Realities
Extended reality (XR) such as VR and AR have been increasingly adopted across domains in cognitively challenging activities such as learning, shopping, and gaming among others. There are a few concerns about the inferior cognitive affordance of XR-mediated functioning, e.g., with respect to memory retention. For better understanding how different XR technologies influence memory performance (e.g., recognition), we examine the effects of VR and AR -mediation on the ability to remember (i.e., recognize afterward) text and image-based information based on a 2 × 2 between-subject experiment (n = 155). The results indicate that VR had a negative main effect on text-based information recognition but no effect on image-based information recognition. AR had no significant main effect on the recognition of either information types. Overall, the findings as further supported by the interaction effects analysis, suggest that for memory recognition, it is always best to have a fully physical (no-AR & no-VR) or fully digital environment (AR & VR) compared to having either VR or AR alone
Institutional Environment and Overinvestment in Emerging Markets-Empirical Evidence from Chinese Listed Companies
We use China’s unique institutional environment as a basis to study the country’s enterprise overinvestment behavior. In recent years, China has seen a surge in enterprise investment due to the huge availability of investment funds leading to difficulties in governing listed firms in the country. We separately analyze the impact of government intervention, rule of law and financial development of various regions on the overinvestment behavior of the listed companies. The results show that government intervention is positively related to overinvestment of listed companies. However, rule of law and financial development are negatively related to overinvestment of listed companies. In addition, the results further show that improved institutional environment can restrict overinvestment in listed companies. Further research indicates that, compared to the rule of law and financial development, government intervention is a fundamental factor which influences overinvestment the most. The study’s results have implications, particularly for the regulators, as they provide useful and detailed information which can be used in the design of more appropriate and functional systems to govern listed companies and help in curbing the overinvestment problem. Keywords: Government intervention; rule of law; financial development; overinvestment, Emerging Market
Quality Difference Study of Six Varieties of Ganoderma lucidum with Different Origins
The quality difference of six varieties Ganoderma lucidum with different origins was investigated in this study by comparing the contents of ganoderic acid A and B, polysaccharide, and triterpenoids. The contents of ganoderic acid A and B in G. lucidum were analyzed by ultra performance liquid chromatography (UPLC). There was higher content of ganoderic acid A in G. lucidum of Dabie Mountain and Longquan. The G. lucidum from Longquan has the highest content of ganoderic acid B. The content of polysaccharide was determined by Anthrone–sulfuric acid method. The highest of polysaccharide content is G. lucidum from Liaocheng. The content of triterpenoid in G. lucidum was quantified by ultraviolet spectrophotometer at 548.1 nm using Ursolic acid as standard. The G. lucidum from Dabie Mountain has the highest content of triterpenoids. In summary, the content of ganoderic acid A and B, polysaccharide, and triterpenoids in G. lucidum with different origins are remarkably different, which may be caused by the conditions of cultivation and geographic environment
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