218 research outputs found
Dominant speaker detection in multipoint video communication using Markov chain with non-linear weights and dynamic transition window
This paper proposes an enhanced discrete-time Markov chain algorithm in predicting dominant speaker(s) for multipoint video communication system in the presence of transient speech. The proposed algorithm exploits statistical properties of the past speech patterns to accurately predict the dominant speaker for the next time state. Non-linear weights-based coefficients are employed in the enhanced Markov chain for both the initial state vector and transition probability matrix. These weights significantly improve the time taken to predict a new dominant speaker during a conference session. In addition, a mechanism to dynamically modify the size of the transition probability matrix window/container is introduced to improve the adaptability of the Markov chain towards the variability of speech characteristics. Simulation results indicate that for an 11 conference participants test scenario, the enhanced Markov chain prediction algorithm registered an 85% accuracy in predicting a dominant speaker when compared to an ideal case where there is no transient speech. Misclassification of dominant speakers due to transient speech was also reduced by 87%
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A regulatory mutant on TRIM26 conferring the risk of nasopharyngeal carcinoma by inducing low immune response.
The major histocompatibility complex (MHC) is most closely associated with nasopharyngeal carcinoma (NPC), but the complexity of its genome structure has proven challenging for the discovery of causal MHC loci or genes. We conducted a targeted MHC sequencing in 40 Cantonese NPC patients followed by a two-stage replication in 1065 NPC cases and 2137 controls of Southern Chinese descendent. Quantitative RT-PCR analysis (qRT-PCR) was used to detect gene expression status in 108 NPC and 43 noncancerous nasopharyngeal (NP) samples. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) were used to assess the transcription factor binding site. We discovered that a novel SNP rs117565607_A at TRIM26 displayed the strongest association (OR = 1.909, Pcombined = 2.750 × 10-19 ). We also observed that TRIM26 was significantly downregulated in NPC tissue samples with genotype AA/AT than TT. Immunohistochemistry (IHC) test also found the TRIM26 protein expression in NPC tissue samples with the genotype AA/AT was lower than TT. According to computational prediction, rs117565607 locus was a binding site for the transcription factor Yin Yang 1 (YY1). We observed that the luciferase activity of YY1 which is binding to the A allele of rs117565607 was suppressed. ChIP data showed that YY1 was binding with T not A allele. Significance analysis of microarray suggested that TRIM26 downregulation was related to low immune response in NPC. We have identified a novel gene TRIM26 and a novel SNP rs117565607_A associated with NPC risk by regulating transcriptional process and established a new functional link between TRIM26 downregulation and low immune response in NPC
Experimental Study on the Failure Characteristics and Damage Evolution of Sandstones from Typical Buried Depths in High In Situ Stress Area
AbstractThis study is aimed at exploring the mechanical properties and failure characteristics of the rocks surrounding a railway tunnel in Qinghai-Tibet Plateau at typical buried depths. Uniaxial compression and AE experiments were carried out on sandstones taken from the same borehole. The results show that the elastic modulus and peak strength of the 750 m depth sandstones are much higher than those of the 350 m depth sandstones. The crack evolution in the 750 m depth sandstones was more orderly, and its brittle failure characteristics were more obvious as compared with the 350 m depth sandstones. The fractal dimension of the samples from the typical depths reached the minimum value when the fracture volume state changed from compression to expansion. In addition, the damage variable based on the crack volumetric strain theory (DC) and cumulative ring counts of acoustic emission (DA) can, respectively, reflect the generation and penetration of cracks and the physical properties of rocks at the two typical depths. The combination of DC and DA can be used to analyze the evolution of the sandstone’s damage. The research results have basic theoretical significance for the excavation and geological disaster prevention of tunnels in sandstone sections at typical depths in the Qinghai-Tibet Plateau
NF45/NF90-mediated rDNA transcription provides a novel target for immunosuppressant development
Herein, we demonstrate that NFAT, a key regulator of the immune response, translocates from cytoplasm to nucleolus and interacts with NF45/NF90 complex to collaboratively promote rDNA transcription via triggering the directly binding of NF45/NF90 to the ARRE2-like sequences in rDNA promoter upon T-cell activation in vitro. The elevated pre-rRNA level of T cells is also observed in both mouse heart or skin transplantation models and in kidney transplanted patients. Importantly, T-cell activation can be significantly suppressed by inhibiting NF45/NF90-dependent rDNA transcription. Amazingly, CX5461, a rDNA transcription-specific inhibitor, outperformed FK506, the most commonly used immunosuppressant, both in terms of potency and off-target activity (i.e., toxicity), as demonstrated by a series of skin and heart allograft models. Collectively, this reveals NF45/NF90-mediated rDNA transcription as a novel signaling pathway essential for T-cell activation and as a new target for the development of safe and effective immunosuppressants
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Plastid phylogenomic insights into relationships of all flowering plant families
Background
Flowering plants (angiosperms) are dominant components of global terrestrial ecosystems, but phylogenetic relationships at the familial level and above remain only partially resolved, greatly impeding our full understanding of their evolution and early diversification. The plastome, typically mapped as a circular genome, has been the most important molecular data source for plant phylogeny reconstruction for decades.
Results
Here, we assembled by far the largest plastid dataset of angiosperms, composed of 80 genes from 4792 plastomes of 4660 species in 2024 genera representing all currently recognized families. Our phylogenetic tree (PPA II) is essentially congruent with those of previous plastid phylogenomic analyses but generally provides greater clade support. In the PPA II tree, 75% of nodes at or above the ordinal level and 78% at or above the familial level were resolved with high bootstrap support (BP ≥ 90). We obtained strong support for many interordinal and interfamilial relationships that were poorly resolved previously within the core eudicots, such as Dilleniales, Saxifragales, and Vitales being resolved as successive sisters to the remaining rosids, and Santalales, Berberidopsidales, and Caryophyllales as successive sisters to the asterids. However, the placement of magnoliids, although resolved as sister to all other Mesangiospermae, is not well supported and disagrees with topologies inferred from nuclear data. Relationships among the five major clades of Mesangiospermae remain intractable despite increased sampling, probably due to an ancient rapid radiation.
Conclusions
We provide the most comprehensive dataset of plastomes to date and a well-resolved phylogenetic tree, which together provide a strong foundation for future evolutionary studies of flowering plants
The Large High Altitude Air Shower Observatory (LHAASO) Science White Paper
The Large High Altitude Air Shower Observatory (LHAASO) project is a new
generation multi-component instrument, to be built at 4410 meters of altitude
in the Sichuan province of China, with the aim to study with unprecedented
sensitivity the spec trum, the composition and the anisotropy of cosmic rays in
the energy range between 10 and 10 eV, as well as to act
simultaneously as a wide aperture (one stereoradiant), continuously-operated
gamma ray telescope in the energy range between 10 and eV. The
experiment will be able of continuously surveying the TeV sky for steady and
transient sources from 100 GeV to 1 PeV, t hus opening for the first time the
100-1000 TeV range to the direct observations of the high energy cosmic ray
sources. In addition, the different observables (electronic, muonic and
Cherenkov/fluorescence components) that will be measured in LHAASO will allow
to investigate origin, acceleration and propagation of the radiation through a
measurement of energy spec trum, elemental composition and anisotropy with
unprecedented resolution. The remarkable sensitivity of LHAASO in cosmic rays
physics and gamma astronomy would play a key-role in the comprehensive general
program to explore the High Energy Universe. LHAASO will allow important
studies of fundamental physics (such as indirect dark matter search, Lorentz
invariance violation, quantum gravity) and solar and heliospheric physics. In
this document we introduce the concept of LHAASO and the main science goals,
providing an overview of the project.Comment: This document is a collaborative effort, 185 pages, 110 figure
Neutrino Physics with JUNO
The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe
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