243 research outputs found
Data Processing Pipeline for Pointing Observations of Lunar-based Ultraviolet Telescope
We describe the data processing pipeline developed to reduce the pointing
observation data of Lunar-based Ultraviolet Telescope (LUT), which belongs to
the Chang'e-3 mission of the Chinese Lunar Exploration Program. The pointing
observation program of LUT is dedicated to monitor variable objects in a
near-ultraviolet (245-345 nm) band. LUT works in lunar daytime for sufficient
power supply, so some special data processing strategies have been developed
for the pipeline. The procedures of the pipeline include stray light removing,
astrometry, flat fielding employing superflat technique, source extraction and
cosmic rays rejection, aperture and PSF photometry, aperture correction, and
catalogues archiving, etc. It has been intensively tested and works smoothly
with observation data. The photometric accuracy is typically ~0.02 mag for LUT
10 mag stars (30 s exposure), with errors come from background noises,
residuals of stray light removing, and flat fielding related errors. The
accuracy degrades to be ~0.2 mag for stars of 13.5 mag which is the 5{\sigma}
detection limit of LUT.Comment: 10 pages, 7 figures, 4 tables. Minor changes and some expounding
words added. Version accepted for publication in Astrophysics and Space
Science (Ap&SS
An Hα Imaging Survey of All (Ultra)luminous Infrared Galaxies at Decl. ≥ -30 in the GOALS Sample
This paper presents the result of Hα imaging for luminous and ultraluminous infrared galaxies. It is a complete subsample of the Great Observatories All-sky LIRG Survey (GOALS) with decl. ≥ -30 , and consists of 148 galaxies with log(L IR/L ) ≥ 11.0. All the Hα images were carried out using the 2.16 m telescope at the Xinglong Station of the National Astronomy Observatories, Chinese Academy of Sciences (NAOC), during the year from 2006 to 2009. We obtained the pure Hα luminosity for each galaxy and corrected the luminosity for [N ii] emission, filter transmission, and extinction. We also classified these galaxies based on their morphology and interaction. We found that the distribution of star-forming regions in these galaxies is related to this classification. As the merging process advanced, these galaxies tended to have a more compact distribution of star-forming regions, higher L IR, and warmer IR-color (f 60/f 100). These results imply that the degree of dynamical disturbance plays an important role in determining the distribution of a star-forming region
Metabolic engineering of Escherichia coli for the biosynthesis of alpha-pinene
Background: alpha-Pinene is an important natural product that is widely used in flavorings, fragrances, medicines, fine chemicals and high-density renewable fuels. Currently, alpha-Pinene used in industry is mainly produced either by tapping trees (gum turpentine) or as a byproduct of paper pulping (crude sulfate turpentine, CST). However, the extraction of it from trees is tedious and inefficient and requires substantial expenditure of natural resources. Therefore, it is necessary to seek sustainable technologies for alpha-pinene production
Effect of YiShenJianPi recipe on semen quality and sperm mitochondria in mice with oligoasthenozoospermia induced by tripterygium glycosides
Background:Kidney tonifying - spleen strengthening method being one of the modalities for treatment of astheno-oligozoospermia is currently commonly used in the clinical setting. To investigate the mechanism of YiShenJianPi (YSJP) Recipe, used in Traditional Chinese Medicine to benefit “the kidney” and strengthen “the spleen”.Materials and Methods: Oligoasthenozoospermia, male BALB/c mice were randomly divided into normal control, disease model, positive control, low-dosage and high-dosage groups. Oligoasthenozoospermia was induced by tripterygium glucosides intragastric administration before treatment started.Through using computer-aided sperm analysis to test the changes in sperm quality, utilizing flow cytometry to test the percentage of sperm with normal mitochondrial transmembrane potential (JC-1 + %), utilizing X-ray microscopy to observe epididymal sperm ultra-microstructure placing special emphasis and photographing the differences in mitochondria of the flagellum region.Results: Compared with DM, sperm quality of the treated mice was significantly better (P<0.05, respectively). Compared with PC, the LD group had significantly better quality sperms, while the parameters in the HD group were numerically better. Compared with NC, all other groups had significantly lower percentage of sperms with normal mitochondrial membrane potential. In PC, LD and HD groups, the percentage of sperms with normal mitochondrial membrane potential was significantly higher than that of D. The 9+9+2 mitochondrial sheath structure was complete in NC but damaged in DM. In the treatment groups, this structure was fairly clear.Conclusion: YSJP improved semen quality with oligoasthenozoospermia by improving sperm mitochondrial membrane potential and restoring sperm mitochondrial ultrastructure.Keywords: traditional Chinese medicine, oligoasthenozoospermia, semen quality, mitochondrial membrane potential, mitochondrial ultrastructur
Star Formation Properties in Barred Galaxies(SFB). I. Ultraviolet-to-Infrared Imaging and Spectroscopic Studies of NGC 7479
Large-scale bars and minor mergers are important drivers for the secular
evolution of galaxies. Based on ground-based optical images and spectra as well
as ultraviolet data from the Galaxy Evolution Explorer and infrared data from
the Spitzer Space Telescope, we present a multi-wavelength study of star
formation properties in the barred galaxy NGC 7479, which also has obvious
features of a minor merger. Using various tracers of star formation, we find
that under the effects of both a stellar bar and a minor merger, star formation
activity mainly takes place along the galactic bar and arms, while the star
formation rate changes from the bar to the disk. With the help of spectral
synthesis, we find that strong star formation took place in the bar region
about 100 Myr ago, and the stellar bar might have been 10 Gyr old. By
comparing our results with the secular evolutionary scenario from Jogee et al.,
we suggest that NGC 7479 is possibly in a transitional stage of secular
evolution at present, and it may eventually become an earlier type galaxy or a
luminous infrared galaxy. We also note that the probable minor merger event
happened recently in NGC 7479, and we find two candidates for minor merger
remnants.Comment: 33 pages, 10 figures, 4 tables; accepted for publication in AJ, 142,
3
Transcriptome analysis of Medicago lupulina seedlings leaves treated by high calcium provides insights into calcium oxalate formation
Abstract(#br) Background and aim(#br)Calcium oxalate (CaOx) is a common biomineral found in the plant kingdom. Crystals of CaOx occur in different plant tissues, such as leaves and stems. However, little is known about the biosynthesis of CaOx in oxalate-accumulating plants. Moreover, the literature on genes related to CaOx formation under high-calcium environment is scarce. In the present study, the physiological parameters and the transcript profiles of Medicago lupulina leaves treated with 0.1 and 25 mM Ca 2+ were analyzed to study the genes involved in the biosynthesis of CaOx.(#br) Results(#br)We demonstrated that exposure to high external calcium concentration induced H 2 O 2 production, ascorbic acid degradation, and CaOx accumulation in M. lupulina leaves. Moreover, we identified..
IRAS F13308+5946: A Possible Transition Phase From Type I ULIRG To Optical Quasar
We present a stellar population synthesis study of a type I luminous infrared
galaxy (LIRG): IRAS F13308+5946. It is a quasar with absolute magnitude Mi =
-22.56 and has a spectral feature of a Seyfert 1.5 galaxy. Optical images show
characteristics of later stages of a merger. With the help of the stellar
synthesis code STARLIGHT (Cid Fernandes et al. 2005) and both Calzetti et al.
(2000) and Leitherer et al.'s (2002) extinction curves, we estimate the past
infrared (IR) luminosities of the host galaxy and find it may have experienced
an ultraluminous infrared galaxy (ULIRG) phase for nearly 300 Myr, so this
galaxy has probably experienced a type I ULIRG phase. Both nuclear starburst
and active galactic nuclei (AGN) contribute to the present IR luminosity
budget, and starburst contributes ~70%. The mass of supermassive black-hole
(SMBH) is M_BH = 1.8*10^8 M_sun and the Eddington ratio L_bol/L_Edd is 0.12,
which both approximate to typical values of PG QSOs. These results indicate
that IRAS F13308+5946 is probably at the transitional phase from a type I ULIRG
to a classical QSO.Comment: 11 pages, 10 figures, Accepted for publication in Ap
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