22,904 research outputs found
Reactive oxygen species promote chloroplast dysfunction and salicylic acid accumulation in fumonisin B1-induced cell death
AbstractWe report a novel regulatory mechanism by which reactive oxygen species (ROS) regulate fumonisin B1 (FB1)-induced cell death. We found that FB1 induction of light-dependent ROS production promoted the degradation of GFP-labeled chloroplast proteins and increased phenylalanine ammonia lyase (PAL) activity, PAL1 gene expression and SA content, while pretreatment with ROS manipulators reversed these trends. Moreover, treatment with H2O2 or 3-amino-1,2,4-triazole increased PAL activity, PAL1 gene expression and SA content. PAL inhibitor significantly blocked FB1-induced lesion formation and SA increase. Our results demonstrate that light-dependent ROS accumulation stimulates the degradation of chloroplastic proteins and up-regulates PAL-mediated SA synthesis, thus promoting FB1-induced light-dependent cell death
Image Source Identification Using Convolutional Neural Networks in IoT Environment
Digital image forensics is a key branch of digital forensics that based on forensic analysis of image authenticity and image content. The advances in new techniques, such as smart devices, Internet of Things (IoT), artificial images, and social networks, make forensic image analysis play an increasing role in a wide range of criminal case investigation. This work focuses on image source identification by analysing both the fingerprints of digital devices and images in IoT environment. A new convolutional neural network (CNN) method is proposed to identify the source devices that token an image in social IoT environment. The experimental results show that the proposed method can effectively identify the source devices with high accuracy
Prokineticin 2 Is a Target Gene of Proneural Basic Helix-Loop-Helix Factors for Olfactory Bulb Neurogenesis
Prokineticin 2, a cysteine-rich secreted protein, regulates diverse biological functions including the neurogenesis of olfactory bulb. Here we show that the PK2 gene is a functional target gene of proneural basic helix-loop-helix (bHLH) factors. Neurogenin 1 and MASH1 activate PK2 transcription by binding to E-box motifs on the PK2 promoter with the same set of E-boxes critical for another pair of bHLH factors, CLOCK and BMAL1, in the regulation of circadian clock. Our results establish PK2 as a common functional target gene for different bHLH transcriptional factors in mediating their respective functions
Uncertainty-Aware Decision Transformer for Stochastic Driving Environments
Offline Reinforcement Learning (RL) has emerged as a promising framework for
learning policies without active interactions, making it especially appealing
for autonomous driving tasks. Recent successes of Transformers inspire casting
offline RL as sequence modeling, which performs well in long-horizon tasks.
However, they are overly optimistic in stochastic environments with incorrect
assumptions that the same goal can be consistently achieved by identical
actions. In this paper, we introduce an UNcertainty-awaRE deciSion Transformer
(UNREST) for planning in stochastic driving environments without introducing
additional transition or complex generative models. Specifically, UNREST
estimates state uncertainties by the conditional mutual information between
transitions and returns, and segments sequences accordingly. Discovering the
`uncertainty accumulation' and `temporal locality' properties of driving
environments, UNREST replaces the global returns in decision transformers with
less uncertain truncated returns, to learn from true outcomes of agent actions
rather than environment transitions. We also dynamically evaluate environmental
uncertainty during inference for cautious planning. Extensive experimental
results demonstrate UNREST's superior performance in various driving scenarios
and the power of our uncertainty estimation strategy
Analysis of the Hydroelastic Performance of Very Large Floating Structures Based on Multimodules Beam Theory
The hydroelastic behavior of very large floating structures (VLFSs) is investigated based on the proposed multimodules beam theory (MBT). To carry out the analysis, the VLFS is first divided into multiple submodules that are connected through their gravity center by a spatial beam with specific stiffness. The external force exerted on the submodules includes the wave hydrodynamic force as well as the beam bending force due to the relative displacements of different submodules. The wave hydrodynamic force is computed based on three-dimensional potential theory. The beam bending force is expressed in the form of a stiffness matrix. The motion response defined at the gravity center of the submodules is solved by the multibody hydrodynamic control equations; then both the displacement and the structure bending moment of the VLFS are determined from the stiffness matrix equations. To account for the moving point mass effects, the proposed method is extended to the time domain based on impulse response function (IRF) theory. The method is verified by comparison with existing results. Detailed results through the displacement and bending moment of the VLFS are provided to show the influence of the number of the submodules and the influence of the moving point mass
Boosting Offline Reinforcement Learning for Autonomous Driving with Hierarchical Latent Skills
Learning-based vehicle planning is receiving increasing attention with the
emergence of diverse driving simulators and large-scale driving datasets. While
offline reinforcement learning (RL) is well suited for these safety-critical
tasks, it still struggles to plan over extended periods. In this work, we
present a skill-based framework that enhances offline RL to overcome the
long-horizon vehicle planning challenge. Specifically, we design a variational
autoencoder (VAE) to learn skills from offline demonstrations. To mitigate
posterior collapse of common VAEs, we introduce a two-branch sequence encoder
to capture both discrete options and continuous variations of the complex
driving skills. The final policy treats learned skills as actions and can be
trained by any off-the-shelf offline RL algorithms. This facilitates a shift in
focus from per-step actions to temporally extended skills, thereby enabling
long-term reasoning into the future. Extensive results on CARLA prove that our
model consistently outperforms strong baselines at both training and new
scenarios. Additional visualizations and experiments demonstrate the
interpretability and transferability of extracted skills
Fabrication and mechanical properties of Ti<sub>2</sub>AlN/TiAl composite with continuous network structure
Nitrogen was introduced into TiAl pre-alloyed powder using high-temperature gas nitriding, and Ti2AlN/TiAl composites with a continuous network structure of the reinforced phase were prepared via spark plasma sintering. The results show that the hardness of the composite is significantly higher than that of TiAl alloy, and increases with the increase of nitriding time. The strengthening effect is originated from the synergistic effect of the solid-solution strengthening caused by the nitriding of the powder, the continuous network of the Ti2AlN phase with high hardness and elastic modulus, and the increase of dislocation density. Additionally, the compressive strength of the Ti2AlN/TiAl composites is lower than that of the TiAl alloy, which is related to a part of Ti2AlN particles that are directly formed after nitriding and excessive reinforcement content.</p
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