1,853 research outputs found
Revisit assignments of the new excited states with QCD sum rules
In this article, we distinguish the contributions of the positive parity and
negative parity states, study the masses and pole residues of the
1S, 1P, 2S and 2P states with the spin and
using the QCD sum rules in a consistent way, and revisit the
assignments of the new narrow excited states. The predictions
support assigning the to be the 1P state with
, assigning the to be the 1P
state with or the 2S state with
, and assigning to be the 2S
state with .Comment: 19 pages, 22 figures. arXiv admin note: text overlap with
arXiv:1705.0774
An initial biochemical and cell biological characterization of the mammalian homologue of a central plant developmental switch, COP1
BACKGROUND: Constitutive photomorphogenic 1 (COP1) has been defined as a central regulator of photomorphogenic development in plants, which targets key transcription factors for proteasome-dependent degradation. Although COP1 mammalian homologue has been previously reported, its function and distribution in animal kingdom are not known. RESULTS: Here we report the characterization of full-length human and mouse COP1 cDNAs and the genomic structures of the COP1 genes from several different species. Mammalian COP1 protein binds to ubiquitinated proteins in vivo and is itself ubiquitinated. Furthermore, mammalian COP1 is predominately nuclear localized and exists primarily as a complex of over 700 kDa. Through mutagenesis studies, we have defined a leucine-rich nuclear export signal (NES) within the coiled-coil domain of mammalian COP1 and a nuclear localization signal (NLS), which is composed of two clusters of positive-charged amino acids, bridged by the RING finger. Disruption of the RING finger structure abolishes the nuclear import, while deletion of the entire RING finger restores the nuclear import. CONCLUSIONS: Our data suggest that mammalian COP1, similar to its plant homologue, may play a role in ubiquitination. Mammalian COP1 contains a classic leucine-rich NES and a novel bipartite NLS bridged by a RING finger domain. We propose a working model in which the COP1 RING finger functions as a structural scaffold to bring two clusters of positive-charged residues within spatial proximity to mimic a bipartite NLS. Therefore, in addition to its well-characterized role in ubiquitination, the RING finger domain may also play a structural role in nuclear import
A Knowledge-Based Simulated Annealing Algorithm to Multiple Satellites Mission Planning Problems
The multiple satellites mission planning is a complex combination optimization problem. A knowledge-based simulated annealing algorithm is proposed to the multiple satellites mission planning problems. The experimental results suggest that the proposed algorithm is effective to the given problem. The knowledge-based simulated annealing method will provide a useful reference for the improvement of existing optimization approaches
Improved Synchronous Machine Rotor Design for the Easy Assembly of Excitation Coils Based on Surrogate Optimization
This paper introduces a new rotor design for the easy insertion and removal of rotor windings. The shape of the rotor is optimized based on a surrogate method in order to achieve low power loss under the maximum power output. The synchronous machine with the new rotor is evaluated in 2-D finite element software and validated by experiments. This rotor shows great potential for reducing the maintenance and repair costs of synchronous machines, making it particularly suited for low-cost mass production markets including gen-sets, steam turbines, wind power generators, and hybrid electric vehicles
Numerical Research on The Nozzle Damping Effect by A Wave Attenuation Method
AbstractNozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors. For an engineering solid rocket motor that experiences combustion instability at the end of burning, a wave attenuation method is proposed to assess the nozzle damping characteristics numerically. In this method, a periodic pressure oscillation signal which frequency equals to the first acoustic mode is superimposed on a steady flow at the head end of the chamber. When the pressure oscillation is turned off, the decay rate of the pressure can be used to determine the nozzle attenuation constant. The damping characteristics of three other nozzle geometries are numerically studied with this method under the same operating condition. The results show that the convex nozzle provides more damping than the conical nozzle which in turn provides more damping than the concave nozzle. All the three nozzles have better damping effect than that of basic nozzle geometry. At last, the phase difference in the chamber is analyzed, and the numerical pressure distribution satisfies well with theoretical distribution
Electrical Probing of Field-Driven Cascading Quantized Transitions of Skyrmion Cluster States in MnSi Nanowires
Magnetic skyrmions are topologically stable whirlpool-like spin textures that
offer great promise as information carriers for future ultra-dense memory and
logic devices1-4. To enable such applications, particular attention has been
focused on the skyrmions properties in highly confined geometry such as one
dimensional nanowires5-8. Hitherto it is still experimentally unclear what
happens when the width of the nanowire is comparable to that of a single
skyrmion. Here we report the experimental demonstration of such scheme, where
magnetic field-driven skyrmion cluster (SC) states with small numbers of
skyrmions were demonstrated to exist on the cross-sections of ultra-narrow
single-crystal MnSi nanowires (NWs) with diameters, comparable to the skyrmion
lattice constant (18 nm). In contrast to the skyrmion lattice in bulk MnSi
samples, the skyrmion clusters lead to anomalous magnetoresistance (MR)
behavior measured under magnetic field parallel to the NW long axis, where
quantized jumps in MR are observed and directly associated with the change of
the skyrmion number in the cluster, which is supported by Monte Carlo
simulations. These jumps show the key difference between the clustering and
crystalline states of skyrmions, and lay a solid foundation to realize
skyrmion-based memory devices that the number of skyrmions can be counted via
conventional electrical measurements
(E)-Ethyl 2-cyano-3-[4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl]acrylate dihydrate
In the title compound, C27H21N3O2·2H2O, the three benzene rings attached to the heterocyclic imidazole ring are not coplanar with the latter, making dihedral angles of 14.8 (2), 31.4 (2), and 37.5 (2)°, respectively, for the benzene ring planes in the 2-, 4- and 5-positions. In the crystal, there are two water molecules which serve as connectors between the acrylate molecules and stabilize the structure via N—H⋯O, O—H⋯N, C—H⋯O and O—H⋯O hydrogen bonding
Estimating accuracy of RNA-Seq and microarrays with proteomics
<p>Abstract</p> <p>Background</p> <p>Microarrays revolutionized biological research by enabling gene expression comparisons on a transcriptome-wide scale. Microarrays, however, do not estimate absolute expression level accurately. At present, high throughput sequencing is emerging as an alternative methodology for transcriptome studies. Although free of many limitations imposed by microarray design, its potential to estimate absolute transcript levels is unknown.</p> <p>Results</p> <p>In this study, we evaluate relative accuracy of microarrays and transcriptome sequencing (RNA-Seq) using third methodology: proteomics. We find that RNA-Seq provides a better estimate of absolute expression levels.</p> <p>Conclusion</p> <p>Our result shows that in terms of overall technical performance, RNA-Seq is the technique of choice for studies that require accurate estimation of absolute transcript levels.</p
Giant room temperature anomalous Hall effect and magnetically tuned topology in the ferromagnetic Weyl semimetal Co2MnAl
Weyl semimetals (WSM) have been extensively studied due to their exotic
properties such as topological surface states and anomalous transport
phenomena. Their band structure topology is usually predetermined by material
parameters and can hardly be manipulated once the material is formed. Their
unique transport properties appear usually at very low temperature, which sets
challenges for practical device applications. In this work, we demonstrate a
way to modify the band topology via a weak magnetic field in a ferromagnetic
topological semimetal, Co2MnAl, at room temperature. We observe a tunable,
giant anomalous Hall effect, which is induced by the transition between Weyl
points and nodal rings as rotating the magnetization axis. The anomalous Hall
conductivity is as large as that of a 3D quantum anomalous Hall effect (QAHE),
with the Hall angle reaching a record value (21%) at the room temperature among
magnetic conductors. Furthermore, we propose a material recipe to generate the
giant anomalous Hall effect by gaping nodal rings without requiring the
existence of Weyl points. Our work reveals an ideal intrinsically magnetic
platform to explore the interplay between magnetic dynamics and topological
physics for the development of a new generation of spintronic devices.Comment: 4 figures, 8 pages for the main text. The supplementary materials are
included to
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