329 research outputs found
Robust Discontinuity Indicators for High-Order Reconstruction of Piecewise Smooth Functions
In many applications, piecewise continuous functions are commonly
interpolated over meshes. However, accurate high-order manipulations of such
functions can be challenging due to potential spurious oscillations known as
the Gibbs phenomena. To address this challenge, we propose a novel approach,
Robust Discontinuity Indicators (RDI), which can efficiently and reliably
detect both C^{0} and C^{1} discontinuities for node-based and cell-averaged
values. We present a detailed analysis focusing on its derivation and the
dual-thresholding strategy. A key advantage of RDI is its ability to handle
potential inaccuracies associated with detecting discontinuities on non-uniform
meshes, thanks to its innovative discontinuity indicators. We also extend the
applicability of RDI to handle general surfaces with boundaries, features, and
ridge points, thereby enhancing its versatility and usefulness in various
scenarios. To demonstrate the robustness of RDI, we conduct a series of
experiments on non-uniform meshes and general surfaces, and compare its
performance with some alternative methods. By addressing the challenges posed
by the Gibbs phenomena and providing reliable detection of discontinuities, RDI
opens up possibilities for improved approximation and analysis of piecewise
continuous functions, such as in data remap.Comment: 37 pages, 37 figures, submitted to Computational and Applied
Mathematics (COAM
Decarbonization of resin-bonded magnesia-graphite composite refractories
Experimental design and procedure -- Decarbonization as a function of temperature and atmosphere -- Direct carbon oxidation as a function of a brick composition -- Direct carbon oxidation as a function of brick composition -- Decarbonizing kinetics in direct carbon oxidation -- Role of antioxidants (Al, Si and SiC) on carbon protection
Human Cytomegalovirus Encoded miR-US25-1-5p Attenuates CD147/EMMPRIN-Mediated Early Antiviral Response.
Cellular receptor-mediated signaling pathways play critical roles during the initial immune response to Human Cytomegalovirus (HCMV) infection. However, the involvement of type-I transmembrane glycoprotein CD147/EMMPRIN (extracellular matrix metalloproteinase inducer) in the antiviral response to HCMV infection is still unknown. Here, we demonstrated the specific knockdown of CD147 significantly decreased HCMV-induced activation of NF-κB and Interferon-beta (IFN-β), which contribute to the cellular antiviral responses. Next, we confirmed that HCMV-encoded miR-US25-1-5p could target the 3 UTR (Untranslated Region) of CD147 mRNA, and thus facilitate HCMV lytic propagation at a low multiplicity of infection (MOI). The expression and secretion of Cyclophilin A (sCyPA), as a ligand for CD147 and a proinflammatory cytokine, were up-regulated in response to HCMV stimuli. Finally, we confirmed that CD147 mediated HCMV-triggered antiviral signaling via the sCyPA-CD147-ERK (extracellular regulated protein kinases)/NF-κB axis signaling pathway. These findings reveal an important HCMV mechanism for evading antiviral innate immunity through its encoded microRNA by targeting transmembrane glycoprotein CD147, and a potential cause of HCMV inflammatory disorders due to the secretion of proinflammatory cytokine CyPA
A Case based Online Trajectory Planning Method of Autonomous Unmanned Combat Aerial Vehicles with Weapon Release Constraints
As a challenging and highly complex problem, the trajectory planning for unmanned combat aerial vehicle (UCAV) focuses on optimising flight trajectory under such constraints as kinematics and complicated battlefield environment. An online case-based trajectory planning strategy is proposed in this study to achieve rapid control variables solution of UCAV flight trajectory for the of delivery airborne guided bombs. Firstly, with an analysis of the ballistic model of airborne guided bombs, the trajectory planning model of UCAVs is established with launch acceptable region (LAR) as a terminal constraint. Secondly, a case-based planning strategy is presented, which involves four cases depending on the situation of UCAVs at the current moment. Finally, the feasibility and efficiency of the proposed planning strategy is validated by numerical simulations, and the results show that the presented strategy is suitable for UCAV performing airborne guided delivery missions in dynamic environments
Path Signature Neural Network of Cortical Features for Prediction of Infant Cognitive Scores
Studies have shown that there is a tight connection between cognition skills and brain morphology during infancy. Nonetheless, it is still a great challenge to predict individual cognitive scores using their brain morphological features, considering issues like the excessive feature dimension, small sample size and missing data. Due to the limited data, a compact but expressive feature set is desirable as it can reduce the dimension and avoid the potential overfitting issue. Therefore, we pioneer the path signature method to further explore the essential hidden dynamic patterns of longitudinal cortical features. To form a hierarchical and more informative temporal representation, in this work, a novel cortical feature based path signature neural network (CF-PSNet) is proposed with stacked differentiable temporal path signature layers for prediction of individual cognitive scores. By introducing the existence embedding in path generation, we can improve the robustness against the missing data. Benefiting from the global temporal receptive field of CF-PSNet, characteristics consisted in the existing data can be fully leveraged. Further, as there is no need for the whole brain to work for a certain cognitive ability, a top K selection module is used to select the most influential brain regions, decreasing the model size and the risk of overfitting. Extensive experiments are conducted on an in-house longitudinal infant dataset within 9 time points. By comparing with several recent algorithms, we illustrate the state-of-the-art performance of our CF-PSNet (i.e., root mean square error of 0.027 with the time latency of 518 milliseconds for each sample)
Seneca Valley Virus 2C and 3Cpro Induce Apoptosis via Mitochondrion-Mediated Intrinsic Pathway
Seneca Valley virus (SVV) is the only member of the genus Senecavirus of the Picornaviridae family. SVV can selectively infect and lyse tumor cells with neuroendocrine features and is used as an oncolytic virus for treating small-cell lung cancers. However, the detailed mechanism underlying SVV-mediated destruction of tumor cells remains unclear. In this study, we found that SVV can increase the proportion of apoptotic 293T cells in a dose- and time-dependent manner. SVV-induced apoptosis was initiated via extrinsic and intrinsic pathways through activation of caspase-3, the activity of which could be attenuated by a pan-caspase inhibitor (Z-VAD-FMK). We confirmed that SVV 2C and 3Cpro play critical roles in SVV-induced apoptosis. The SVV 2C protein was located solely in the mitochondria and activated caspase-3 to induce apoptosis. SVV 3Cpro induced apoptosis through its protease activity, which was accompanied by release of cytochrome C into the cytoplasm, but did not directly cleave PARP1
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CA1-projecting subiculum neurons facilitate object-place learning.
Recent anatomical evidence suggests a functionally significant back-projection pathway from the subiculum to the CA1. Here we show that the afferent circuitry of CA1-projecting subicular neurons is biased by inputs from CA1 inhibitory neurons and the visual cortex, but lacks input from the entorhinal cortex. Efferents of the CA1-projecting subiculum neurons also target the perirhinal cortex, an area strongly implicated in object-place learning. We identify a critical role for CA1-projecting subicular neurons in object-location learning and memory, and show that this projection modulates place-specific activity of CA1 neurons and their responses to displaced objects. Together, these experiments reveal a novel pathway by which cortical inputs, particularly those from the visual cortex, reach the hippocampal output region CA1. Our findings also implicate this circuitry in the formation of complex spatial representations and learning of object-place associations
Social event detection with retweeting behavior correlation
Event detection over microblogs has attracted great research interest due to its wide application in crisis management and decision making etc. In natural disasters, complex events are reported in real time on social media sites, but these reports are invisible to crisis coordinators. Detecting these crisis events helps watchers to make right decisions rapidly, reducing injuries, deaths and economic loss. In sporting activities, detecting events helps audiences make better and more timely game viewing plans. However, existing event detection techniques are not effective at handling complex social events that evolve over time. In this paper, we propose an event detection method that takes advantage of retweeting behavior for handling the events evolution. Specifically, we first propose a topic model called RL-LDA to capture the social media information over hashtag, location, textual and retweeting behavior. Using RL-LDA, a complex event can be well handled by exploring the correlation between retweeting behavior and the event. Then to maintain the RL-LDA in a dynamic environment, we propose a dynamic update algorithm, which incrementally updates events over real time streams. Experiments over real-world datasets show that RL-LDA detects the temporal evolution of complex events effectively and efficiently
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