347 research outputs found
A search for massive young stellar objects towards 98 CHOH maser sources
Using the 13.7 m telescope of Purple Mountain Observatory (PMO), a survey of
J=1-0 lines of CO and its isotopes was carried out towards 98 methanol maser
sources in January 2008. Eighty-five sources have infrared counterparts within
one arcmin. In the survey, except 43 sources showing complex or multiple-peak
profiles, almost all the CO line profiles of the other 55 sources have
large line widths of 4.5 km s on average and are usually asymmetric.
Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55
sources are with larger than , which can be
identified as possible high-mass young stellar sources. Statistics show that
the CO line widths correlate with the bolometric luminosity of the
associated IRAS sources. We also report the mapping results of two sources:
IRAS 06117+1350 and IRAS 07299-1651 here. Two cores were found in IRAS
06117+1350 and one core was detected in IRAS 07299-1651. The northwest core in
IRAS 06117+1350 and the core in IRAS 07299-1651 can be identified as precursors
of UC\simH{\sc ii} regions or high-mass protostellar objects (HMPOs). The
southeast core of IRAS 06117+1350 has no infrared counterpart, seeming to be on
younger stages than pre-UC\simH{\sc ii} phase.Comment: A search for massive young stellar objects. Accepted to RAA in 201
Residue theorem and summing over Kaluza-Klein excitations
Applying the equations of motion together with corresponding boundary
conditions of bulk profiles at infrared and ultraviolet branes, we verify some
lemmas on the eigenvalues of Kaluze-Klein modes in framework of warped extra
dimension with the custodial symmetry . Using the lemmas and performing properly
analytic extensions of bulk profiles, we present the sufficient condition for a
convergent series of Kaluze-Klein excitations and sum over the series through
the residue theorem. The method can also be applied to sum over the infinite
series of Kaluze-Klein excitations in unified extra dimension. Additional, we
analyze the possible connection between the propagators in five dimensional
full theory and the product of bulk profiles with corresponding propagators of
exciting Kaluze-Klein modes in four dimensional effective theory, and recover
some relations presented in literature for warped and unified extra dimensions
respectively. As an example, we demonstrate that the corrections from neutral
Higgs to the Wilson coefficients of relevant operators for contain the suppression factor comparing
with that from other sectors, thus can be neglected safely.Comment: 44 pages, no figur
医学硕士研究生创新能力培养的探索与思考*
The development of medical career in our country has put forward higher requirements for the innovative ability of medical postgraduates of in China. But the innovative ability of postgraduates does not meet the corresponding requirements. Therefore, cultivating innovative consciousness and improving the innovative ability is the important goal and task of cultivating graduate students. This paper summarizes the idea of cultivating the innovative ability of medical postgraduates, and makes a preliminary exploration and thinking on the cultivation methods of the innovative ability of medical postgraduates from the aspects of the current Situation of innovative ability of medical postgraduates, improving the innovation of the instructors and the cultivation of postgraduates' comprehensive ability and so on. This article on how to cultivate high-level, compound medical graduate students put forward a new view of training. 我国医疗事业发展对我国医学硕士研究生创新能力提出了更高的要求,而硕士研究生的创新能力没有达到相应要求。因此,培养创新意识、提高创新能力是现今培养研究生重要的目标和任务。本文总结了医学硕士研究生创新能力培养的思路,从医学硕士研究生创新能力现况、提高导师创新能力、培养研究生综合能力等方面对医学硕士研究生创新能力的培养方法进行初步探索与思考,就如何培养具有创新能力的高层次、复合型医学硕士研究生提出了培养的新看法
Light Multi-segment Activation for Model Compression
Model compression has become necessary when applying neural networks (NN)
into many real application tasks that can accept slightly-reduced model
accuracy with strict tolerance to model complexity. Recently, Knowledge
Distillation, which distills the knowledge from well-trained and highly complex
teacher model into a compact student model, has been widely used for model
compression. However, under the strict requirement on the resource cost, it is
quite challenging to achieve comparable performance with the teacher model,
essentially due to the drastically-reduced expressiveness ability of the
compact student model. Inspired by the nature of the expressiveness ability in
Neural Networks, we propose to use multi-segment activation, which can
significantly improve the expressiveness ability with very little cost, in the
compact student model. Specifically, we propose a highly efficient
multi-segment activation, called Light Multi-segment Activation (LMA), which
can rapidly produce multiple linear regions with very few parameters by
leveraging the statistical information. With using LMA, the compact student
model is capable of achieving much better performance effectively and
efficiently, than the ReLU-equipped one with same model scale. Furthermore, the
proposed method is compatible with other model compression techniques, such as
quantization, which means they can be used jointly for better compression
performance. Experiments on state-of-the-art NN architectures over the
real-world tasks demonstrate the effectiveness and extensibility of the LMA
High-mass Starless Clumps in the inner Galactic Plane: the Sample and Dust Properties
We report a sample of 463 high-mass starless clump (HMSC) candidates within
and . This sample has been singled out from
10861 ATLASGAL clumps. All of these sources are not associated with any known
star-forming activities collected in SIMBAD and young stellar objects
identified using color-based criteria. We also make sure that the HMSC
candidates have neither point sources at 24 and 70 \micron~nor strong extended
emission at 24 m. Most of the identified HMSCs are infrared (
m) dark and some are even dark at 70 m. Their distribution shows
crowding in Galactic spiral arms and toward the Galactic center and some
well-known star-forming complexes. Many HMSCs are associated with large-scale
filaments. Some basic parameters were attained from column density and dust
temperature maps constructed via fitting far-infrared and submillimeter
continuum data to modified blackbodies. The HMSC candidates have sizes, masses,
and densities similar to clumps associated with Class II methanol masers and
HII regions, suggesting they will evolve into star-forming clumps. More than
90% of the HMSC candidates have densities above some proposed thresholds for
forming high-mass stars. With dust temperatures and luminosity-to-mass ratios
significantly lower than that for star-forming sources, the HMSC candidates are
externally heated and genuinely at very early stages of high-mass star
formation. Twenty sources with equivalent radius pc and
mass surface density g cm could be possible high-mass
starless cores. Further investigations toward these HMSCs would undoubtedly
shed light on comprehensively understanding the birth of high-mass stars.Comment: 16 pages, 15 figures, and 5 tables. Accepted for publication in ApJS.
FITS images for the far-IR to sub-mm data, H2 column density and dust
temperature maps of all the HMSC candidates are available at https:
//yuanjinghua.github.io/hmscs.html. Codes used for this work are publicly
available from https://github.com/yuanjinghua/HMSCs_ca
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