168 research outputs found
Special Purpose Pulsar Telescope for the Detection of Cosmic Gravitational Waves
Pulsars can be used to search for stochastic backgrounds of gravitational
waves of cosmological origin within the very low frequency band (VLF),
to Hz. We propose to construct a special 50 m radio
telescope. Regular timing measurements of about 10 strong millisecond pulsars
will perhaps allow the detection of gravitational waves within VLF or at least
will give a more stringent upper limits.Comment: 5 pages, no figure, Latex fil
Miyun 232 MHz survey 1: Fields centered at: alpha:00(h)41(m), delta:41 deg 12 min and alpha: 07(h)00(m),delta:35 deg 00 min
A new meter-wave survey of sky region north of declination +30 deg is carried out with the Miyun 232 MHz Synthesis Radio Telescope (MSRT). The instrument, observation, and method of data reduction are briefly described. A preliminary catalog, first of a series, for two 8 deg. x 8 deg. regions centered respectively at 35 deg. is presented. On the average 4 - 5 sources per square degree are recorded with position accuracy of 5 sec. / S(Jy). BGPW scale is adopted for the flux density calibration. The accuracy of flux determination is limited by background fluctuation which is about 30 mJy. The catalog is complete for sources with flux larger than 0.25 Jy. The total number of sources listed in the paper amounts to 687. Several extended sources, sources with convex spectra, and one GPS source were found. Spectra of sources with flux larger than 0.5 Jy were also given
Quantized octupole acoustic topological insulator
The Berry phase associated with energy bands in crystals can lead to
quantized quantities, such as the quantization of electric dipole polarization
in an insulator, known as a one-dimensional (1D) topological insulator (TI)
phase. Recent theories have generalized such quantization from dipole to higher
multipole moments, giving rise to the discovery of multipole TIs, which exhibit
a cascade hierarchy of multipole topology at boundaries of boundaries: A
quantized octupole moment in the three-dimensional (3D) bulk can induce
quantized quadrupole moments on its two-dimensional (2D) surfaces, which then
produce quantized dipole moments along 1D hinges. The model of 2D quadrupole TI
has been realized in various classical structures, exhibiting zero-dimensional
(0D) in-gap corner states. Here we report on the realization of a quantized
octupole TI on the platform of a 3D acoustic metamaterial. By direct acoustic
measurement, we observe 0D corner states, 1D hinge states, 2D surface states,
and 3D bulk states, as a consequence of the topological hierarchy from octupole
moment to quadrupole and dipole moment. The critical conditions of forming a
nontrivial octupole moment are further demonstrated by comparing with another
two samples possessing a trivial octupole moment. Our work thus establishes the
multipole topology and its full cascade hierarchy in 3D geometries
Single-site catalyst promoters accelerate metal- catalyzed nitroarene hydrogenation
Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydro- genation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn- TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various reducible groups. The high activity and selectivity of these catalysts result from the creation of oxygen vacancies on the TiO2 surface by single-site Sn, which leads to efficient, selective activation of the nitro group coupled with a reaction involving hydrogen atoms activated on metal nanoparticles
Profiling analysis of long non-coding RNAs in early postnatal mouse hearts
Mammalian cardiomyocytes undergo a critical hyperplastic-to-hypertrophic growth transition at early postnatal age, which is important in establishing normal physiological function of postnatal hearts. In the current study, we intended to explore the role of long non-coding (lnc) RNAs in this transitional stage. We analyzed lncRNA expression profiles in mouse hearts at postnatal day (P) 1, P7 and P28 via microarray. We identified 1,146 differentially expressed lncRNAs with more than 2.0-fold change when compared the expression profiles of P1 to P7, P1 to P28, and P7 to P28. The neighboring genes of these differentially expressed lncRNAs were mainly involved in DNA replication-associated biological processes. We were particularly interested in one novel cardiac-enriched lncRNA, ENSMUST00000117266, whose expression was dramatically down-regulated from P1 to P28 and was also sensitive to hypoxia, paraquat, and myocardial infarction. Knockdown ENSMUST00000117266 led to a significant increase of neonatal mouse cardiomyocytes in G0/G1 phase and reduction in G2/M phase, suggesting that ENSMUST00000117266 is involved in regulating cardiomyocyte proliferative activity and is likely associated with hyperplastic-to-hypertrophic growth transition. In conclusion, our data have identified a large group of lncRNAs presented in the early postnatal mouse heart. Some of these lncRNAs may have important functions in cardiac hyperplastic-to-hypertrophic growth transition
FGF21 ameliorates the neurocontrol of blood pressure in the high fructose-drinking rats
Fibroblast growth factor-21 (FGF21) is closely related to various metabolic and cardiovascular disorders. However, the direct targets and mechanisms linking FGF21 to blood pressure control and hypertension are still elusive. Here we demonstrated a novel regulatory function of FGF21 in the baroreflex afferent pathway (the nucleus tractus solitarii, NTS; nodose ganglion, NG). As the critical co-receptor of FGF21, β-klotho (klb) significantly expressed on the NTS and NG. Furthermore, we evaluated the beneficial effects of chronic intraperitoneal infusion of recombinant human FGF21 (rhFGF21) on the dysregulated systolic blood pressure, cardiac parameters, baroreflex sensitivity (BRS) and hyperinsulinemia in the high fructose-drinking (HFD) rats. The BRS up-regulation is associated with Akt-eNOS-NO signaling activation in the NTS and NG induced by acute intravenous rhFGF21 administration in HFD and control rats. Moreover, the expressions of FGF21 receptors were aberrantly down-regulated in HFD rats. In addition, the up-regulated peroxisome proliferator-activated receptor-γ and -α (PPAR-γ/-α) in the NTS and NG in HFD rats were markedly reversed by chronic rhFGF21 infusion. Our study extends the work of the FGF21 actions on the neurocontrol of blood pressure regulations through baroreflex afferent pathway in HFD rats
Deploying Image Deblurring across Mobile Devices: A Perspective of Quality and Latency
Recently, image enhancement and restoration have become important
applications on mobile devices, such as super-resolution and image deblurring.
However, most state-of-the-art networks present extremely high computational
complexity. This makes them difficult to be deployed on mobile devices with
acceptable latency. Moreover, when deploying to different mobile devices, there
is a large latency variation due to the difference and limitation of deep
learning accelerators on mobile devices. In this paper, we conduct a search of
portable network architectures for better quality-latency trade-off across
mobile devices. We further present the effectiveness of widely used network
optimizations for image deblurring task. This paper provides comprehensive
experiments and comparisons to uncover the in-depth analysis for both latency
and image quality. Through all the above works, we demonstrate the successful
deployment of image deblurring application on mobile devices with the
acceleration of deep learning accelerators. To the best of our knowledge, this
is the first paper that addresses all the deployment issues of image deblurring
task across mobile devices. This paper provides practical
deployment-guidelines, and is adopted by the championship-winning team in NTIRE
2020 Image Deblurring Challenge on Smartphone Track.Comment: CVPR 2020 Workshop on New Trends in Image Restoration and Enhancement
(NTIRE
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