1,288 research outputs found
Extreme Learning Machine Based Non-Iterative and Iterative Nonlinearity Mitigation for LED Communications
This work concerns receiver design for light emitting diode (LED)
communications where the LED nonlinearity can severely degrade the performance
of communications. We propose extreme learning machine (ELM) based
non-iterative receivers and iterative receivers to effectively handle the LED
nonlinearity and memory effects. For the iterative receiver design, we also
develop a data-aided receiver, where data is used as virtual training sequence
in ELM training. It is shown that the ELM based receivers significantly
outperform conventional polynomial based receivers; iterative receivers can
achieve huge performance gain compared to non-iterative receivers; and the
data-aided receiver can reduce training overhead considerably. This work can
also be extended to radio frequency communications, e.g., to deal with the
nonlinearity of power amplifiers
JefiGPU: Jefimenko's Equations on GPU
We have implemented a GPU version of the Jefimenko's equations -- JefiGPU.
Given the proper distributions of the source terms (charge density) and
(current density) in the source volume, the algorithm gives the
electromagnetic fields in the observational region (not necessarily overlaps
the vicinity of the sources). To verify the accuracy of the GPU implementation,
we have compared the obtained results with that of the theoretical ones. Our
results show that the deviations of the GPU results from the theoretical ones
are around 5\%. Meanwhile, we have also compared the performance of the GPU
implementation with a CPU version. The simulation results indicate that the GPU
code is significantly faster than the CPU version. Finally, we have studied the
parameter dependence of the execution time and memory consumption on one NVIDIA
Tesla V100 card. Our code can be consistently coupled to RBG (Relativistic
Boltzmann equations on GPUs) and many other GPU-based algorithms in physics.Comment: 21 pages, 8 figures, 4 table
Characterization of A- and B-type starch granules in Chinese wheat cultivars
AbstractStarch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects: (1) higher amount of ordered short-range structure and a lower relative crystallinity, (2) higher gelatinization onset (To) temperatures and enthalpies (ΔH), and lower gelatinization conclusion temperatures (Tc), (3) greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications
Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449
We presented the multiwavelength analysis of a heavily obscured active
galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray
spectrum using the latest NuSTAR and XMM-Newton data. Its column density
() and photon index () were
reliably obtained by analyzing the broadband X-ray spectrum. However, the
scattering fraction and the intrinsic X-ray luminosity could not be well
constrained. Combined with the information obtained from the mid-infrared
(mid-IR) spectrum and spectral energy distribution (SED) fitting, we derived
its intrinsic X-ray luminosity ()
and scattering fraction (). In addition, we also
derived the following results: (1). The mass accretion rate of central AGN is
about , and the Eddington ratio
is ; (2). The torus of this AGN has a high gas-to-dust
ratio ();
(3). The host galaxy and the central AGN are both in the early stage of
co-evolution.Comment: 12 pages, 5 figures, 3 tables, Accepted to PAS
Possible Way to Synthesize Superheavy Element Z=117
Within the framework of the dinuclear system model, the production of
superheavy element Z=117 in possible projectile-target combinations is analyzed
systematically. The calculated results show that the production cross sections
are strongly dependent on the reaction systems. Optimal combinations,
corresponding excitation energies and evaporation channels are proposed in this
letter, such as the isotopes ^{248,249}Bk in ^{48}Ca induced reactions in 3n
evaporation channels and the reactions ^{45}Sc+^{246,248}Cm in 3n and 4n
channels, and the system ^{51}V+^{244}Pu in 3n channel.Comment: 10 pages, 4 figures, 1 tabl
Identification of MicroRNAs in Two Species of Tomato, \u3ci\u3eSolanum lycopersicum\u3c/i\u3e and \u3ci\u3eSolanum habrochaites\u3c/i\u3e, by Deep Sequencing
MicroRNAs (miRNAs) are ~21 nucleotide (nt), endogenous RNAs that regulate gene expression in plants. Increasing evidence suggests that miRNAs play an important role in species-specific development in plants. However, the detailed miRNA profile divergence has not been performed among tomato species. In this study, the small RNA (sRNA) profiles of Solanum lycopersicum cultivar 9706 and Solanum habrochaites species PI 134417 were obtained by deep sequencing. Sixty-three known miRNA families were identified from these two species, of which 39 were common. Further miRNA profile comparison showed that 24 known non-conserved miRNA families were species-specific between these two tomato species. In addition, six conserved miRNA families displayed an apparent divergent expression pattern between the two tomato species. Our results suggested that species-specific, non-conserved miRNAs and divergent expression of conserved miRNAs might contribute to developmental changes and phenotypic variation between the two tomato species. Twenty new miRNAs were also identified in S. lycopersicum. This research significantly increases the number of known miRNA families in tomato and provides the first set of small RNAs in S. habrochaites. It also suggests that miRNAs have an important role in species-specific plant developmental regulation
CD147 overexpression on synoviocytes in rheumatoid arthritis enhances matrix metalloproteinase production and invasiveness of synoviocytes
Macrophage-like synoviocytes and fibroblast-like synoviocytes (FLS) are known as the most active cells of rheumatoid arthritis (RA) and are close to the articular cartilage in a position enabling them to invade the cartilage. Macrophage-like synoviocytes and FLS expression of matrix metalloproteinases (MMPs) and their interaction has aroused great interest. The present article studied the expression of CD147, also called extracellular matrix metalloproteinase inducer, on monocytes/macrophages and FLS from RA patients and its potential role in enhancing MMPs and the invasiveness of synoviocytes. Expression of CD147 on FLS derived from RA patients and from osteoarthritis patients, and expression of CD147 on monocytes/macrophages from rheumatic synovial fluid and healthy peripheral blood were analyzed by flow cytometry. The levels of CD147, MMP-2 and MMP-9 mRNA in FLS were detected by RT-PCR. The role of CD147 in MMP production and the cells' invasiveness in vitro were studied by the co-culture of FLS with the human THP-1 cell line or monocytes/macrophages, by gel zymography and by invasion assay. The results showed that the expression of CD147 was higher on RA FLS than on osteoarthritis FLS and was higher on monocytes/macrophages from rheumatic synovial fluid than on monocytes/macrophages from healthy peripheral blood. RT-PCR showed that the expressions of CD147, MMP-2 and MMP-9 mRNA was higher in RA FLS than in osteoarthritis FLS. A significantly elevated secretion and activation of MMP-2 and MMP-9 were observed in RA FLS co-cultured with differentiated THP-1 cells or RA synovial monocytes/macrophages, compared with those co-cultured with undifferentiated THP-1 cells or healthy control peripheral blood monocytes. Invasion assays showed an increased number of invading cells in the co-cultured RA FLS with differentiated THP-1 cells or RA synovial monocytes/macrophages. CD147 antagonistic peptide inhibited the MMP production and the invasive potential. Our studies demonstrated that the CD147 overexpression on monocytes/macrophages and FLS in RA patients may be responsible for the enhanced MMP secretion and activation and for the invasiveness of synoviocytes. These findings suggest that CD147 may be one of the important factors in progressive joint destruction of RA and that CD147 may be a potential therapeutic target in RA treatment
Kinematics and star formation toward W33: a central hub as a hub--filament system
We performed a large-scale mapping observation toward the W33 complex and its
surroundings, covering an area of , in CO
(1-0), CO (1-0), and CO (1-0) lines from the Purple Mountain
Observatory (PMO). We found a new hub--filament system ranging from 30 to 38.5
\kms located at the W33 complex. Three supercritical filaments are directly
converging into the central hub W33. Velocity gradients are detected along the
filaments and the accretion rates are in order of . The central hub W33 has a total mass of , accounting for of the mass of the
hub--filament system. This indicates that the central hub is the mass reservoir
of the hub-filament system. Furthermore, 49 ATLASGAL clumps are associated with
the hub--filament system. We find of the clumps to be situated in the
central hub W33 and clustered at the intersections between the filaments and
the W33 complex. Moreover, the distribution of Class I young stellar objects
(YSOs) forms a structure resembling the hub--filament system and peaks at where
the clumps group; it seems to suggest that the mechanisms of clump formation
and star formation in this region are correlated. Gas flows along the filaments
are likely to feed the materials into the intersections and lead to the
clustering and formation of the clumps in the hub--filament system W33. The
star formation in the intersections between the filaments and the W33 complex
might be triggered by the motion of gas converging into the intersections
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