2,311 research outputs found
A NuSTAR Observation of the Gamma-ray Emitting Millisecond Pulsar PSR J1723-2837
We report on the first NuSTAR observation of the gamma-ray emitting
millisecond pulsar binary PSR J1723-2837. X-ray radiation up to 79 keV is
clearly detected and the simultaneous NuSTAR and Swift spectrum is well
described by an absorbed power-law with a photon index of ~1.3. We also find
X-ray modulations in the 3-10 keV, 10-20 keV, 20-79 keV, and 3-79 keV bands at
the 14.8-hr binary orbital period. All these are entirely consistent with
previous X-ray observations below 10 keV. This new hard X-ray observation of
PSR J1723-2837 provides strong evidence that the X-rays are from the
intrabinary shock via an interaction between the pulsar wind and the outflow
from the companion star. We discuss how the NuSTAR observation constrains the
physical parameters of the intrabinary shock model.Comment: Accepted for publication in ApJ. 5 pages, 3 figure
Alkaloid content and essential oil composition of Mahonia breviracema cultivated under different light environments
Light can affect the yields of alkaloid and essential oil in the synthesis of secondary metabolites directly or indirectly through plant growth. Despite Mahonia breviracema being an endemic medicinal species in China, research on the influence of light on production of alkaloid and essential oil is scarce. Thus, this research evaluated the influence of various lighting conditions on alkaloid yields and the composition and yields of the essential oils of M. breviracema. The results revealed significant differences in alkaloid yields, oil yieldsand chemical characteristics of M. breviracema grown in four different light intensities from 10 to 100% full sun shine. The total amount of alkaloids in plants under I30 and I50 was higher than that under I10 and I100 due to the higher biomass of plants. Oil yield of M. breviracema leaf increased linearly with the increase of lightincidence. Plants grown under I10 had less plastoglobuli, which coincided with the lowest oil yield (1.91 g kg-1). The plastoglobuli in chloroplasts increased when the irradiance levels increased, resulting in the highest oil yields under I100 (4.53 g kg-1). The principal components in the leaves of M. breviracema were hexadecanoic acid (10.54-72.19%) and α-ionone (1.25-42.39%). The highest hexadecanoic acid content was obtained under I50, followed by I30, and the highest α-ionone content was obtained under I100. Therefore, it is necessary to control the light environment to obtain raw materials with high quality
Poly[bis(2,2′-bipyridine-κ2 N,N′)heptadeca-μ-oxido-tetraoxidodicopper(II)divanadate(IV)hexavanadate(V)]
In the title complex, [Cu2V8O21(2,2′-bpy)2]n (bpy = bipyridine, C10H8N2), the asymmetric unit contains four independent V atoms briged by 11 O atoms, one of which lies on an inversion center, and a [Cu(2,2′-bpy)]2+ unit. Three V atoms in the polyoxoanion exhibit distorted tetraÂhedral coordination geometries while the fourth V atom adopts a trigonal-bipyramidal geometry. The Cu atom adopts a square-pyramidal geometry being coordinated by two nitroÂgen donors of a 2,2′-bpy ligand, and three bridging O atoms which are linked with V atoms. The V8 polyoxoanion is connected to [Cu(2,2′-bpy)]2+ cations, resulting in a two-dimensional layer structure extending parallel to (010). C—H⋯O hydrogen bonding consolidates the structure
Mining of Related Genes with High Efficiency of Phosphorus Utilization Based on Transcriptome Sequencing in Soybean
Low phosphorus in soil has become an important limit factor affecting the yield and quality of soybean. The excavation and utilization of high phosphorus efficient related genes is an important prerequisite for the analysis of high pho sphorus mechanism and the improvement of genetic breeding. In this study, the high- and low-efficiency soybean germplasms were used to analyze the root transcriptome data under two different phosphorus conditions through the weight gene co-expression network method.The results showed that there were 15305 high-expressed related genes obtained and were divided into 20 modules, and four of them showed different expressions between these two varieties under two phosphorus treatments. Further analysis results of the Melightcyan module revealed that 268 genes were found in this module, and 13 genes of them were up-regulated with low-phosphorus induction and involved in multiple metabolic pathways. Moreover, the related genes in this module which participate in the phospholipid metabolism pathways showed the most highest expression levels. Finally, combined with the previous reports, six kinds of related genes with high efficient utilization of soybean phosphorus were screened out, which could provide
Swift, XMM-Newton, and NuSTAR observations of PSR J2032+4127/MT91 213
We report our recent Swift, NuSTAR, and XMM-Newton X-ray and Lijiang optical
observations on PSR J2032+4127/MT91 213, the gamma-ray binary candidate with a
period of 45-50 years. The coming periastron of the system was predicted to be
in November 2017, around which high-energy flares from keV to TeV are expected.
Recent studies with Chandra and Swift X-ray observations taken in 2015/16
showed that its X-ray emission has been brighter by a factors of ~10 than that
before 2013, probably revealing some on-going activities between the pulsar
wind and the stellar wind. Our new Swift/XRT lightcurve shows no strong
evidence of a single vigorous brightening trend, but rather several strong
X-ray flares on weekly to monthly timescales with a slowly brightening
baseline, namely the low state. The NuSTAR and XMM-Newton observations taken
during the flaring and the low states, respectively, show a denser environment
and a softer power-law index during the flaring state, implying that the pulsar
wind interacted with stronger stellar winds of the companion to produce the
flares. These precursors would be crucial in studying the predicted giant
outburst from this extreme gamma-ray binary during the periastron passage in
late 2017.Comment: 6 pages, including 3 figures and 2 tables. Accepted for publication
in Ap
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