914 research outputs found

    MTD: Multi-Timestep Detector for Delayed Streaming Perception

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    Autonomous driving systems require real-time environmental perception to ensure user safety and experience. Streaming perception is a task of reporting the current state of the world, which is used to evaluate the delay and accuracy of autonomous driving systems. In real-world applications, factors such as hardware limitations and high temperatures inevitably cause delays in autonomous driving systems, resulting in the offset between the model output and the world state. In order to solve this problem, this paper propose the Multi- Timestep Detector (MTD), an end-to-end detector which uses dynamic routing for multi-branch future prediction, giving model the ability to resist delay fluctuations. A Delay Analysis Module (DAM) is proposed to optimize the existing delay sensing method, continuously monitoring the model inference stack and calculating the delay trend. Moreover, a novel Timestep Branch Module (TBM) is constructed, which includes static flow and adaptive flow to adaptively predict specific timesteps according to the delay trend. The proposed method has been evaluated on the Argoverse-HD dataset, and the experimental results show that it has achieved state-of-the-art performance across various delay settings.Comment: 12 pages, accepted by PRCV 2023 (The 6th Chinese Conference on Pattern Recognition and Computer Vision

    Emerald Ash Borer and the application of biological control in Virginia

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    The emerald ash borer (Agrilus planipennis; EAB) is an invasive wood-boring beetle whose larvae feed on ash phloem. After only 1-5 years of infestation, the larvae create extensive tunnels under the bark that disrupt the tree’s ability to transport water and nutrients, which eventually girdles and kills the tree. Since 2008, EAB has spread to all but the eastern-most counties in Virginia. Bological control is one strategy to limit EAB populations. In this project we study control by native agents (woodpeckers) and imported agents (parasitoid wasps). Mathematical models of host-parasitoid interactions and simulations based on both models and field studies will be presented. Our novel contribution extends the basic Nicholson-Bailey model to a partial refuge system, realized in Virginia where EAB infests both ash and white fringetrees with fringetrees less attractive to the parasitoids. We determine ranges for model parameters that result in stable equilibrium populations

    What influences a second generation's decision to join a family firm in China

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    Family business plays an integral role in the development of Chinese economy. Similar to western counterparts, Chinese family firms are facing an urgent business succession issue. As the vital stakeholder in the family business succession, Chinese second generations remain seldom noticed by the academia. It is not clear that what factors influence the forming process of Chinese second generations’ determination to succeed their family firms or to pursue alternative careers and how it is impacted. This study is dedicated to explore and examine various factors that have influence on Chinese second generations’ decisions to enter their family firms or not. Firstly the definition of “family business” will be addressed followed by an illustration of the Chinese family business succession issue. Then, a literature review will be conducted to summarise past findings on this area and the methodology of this study will be justified. Finally, it will discuss main findings of this study and indicate their implications

    Effect of astragaloside on vitamin d-receptor expression after endothelin-1-induced cardiomyocyte injury

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    Background: Astragaloside, which is one of the main components of Astragalus membranaceus, has been widely used in the treatment of congestive heart failure in China, and it can protect cardiomyocytes. Its mechanism of action remains unclear. Therefore, the present study was carried out to investigate the influence of astragaloside on rat cardiomyocytes stimulated with endothelin-1 (ET-1), and explored the underlying mechanism.Materials and Methods: ET-1 was used to stimulate primary rat cardiomyocytes and establish a cardiomyocyte hypertrophy model. Different astragaloside doses were administered in combination with ET-1. Cardiomyocyte hypertrophy and apoptosis were examined using transmission electron microscopy (TEM) and flow cytometry, respectively. The molecular mechanism was explored by analyzing the mRNA of the vitamin D receptor (VDR), cytochrome P450 family 27 subfamily B member 1(CYP27B), cytochrome P450 family 24 subfamily A member 1(CYP24A) and renin mRNA levels by quantificational real-time polymerase chain reaction(qRT-PCR).Results: Rat cardiomyocyte hypertrophy model was established successfully. Astragaloside administration significantly affected cell apoptosis and significantly inhibited ET-1-induced cardiomyocyte hypertrophy in a dose-dependent manner. Astragaloside treatment affected the expression of signaling molecules in the vitamin D axis.Conclusion: Astragaloside inhibits ET-1-induced cardiomyocyte hypertrophy. This effect can be reversed by regulating the levels of the relevant factors in the vitamin D axis.Keywords: cardiomyocyte hypertrophy, Astragaloside, Vitamin D Receptor, reni

    Human activities accelerated the degradation of saline seepweed red beaches by amplifying top‐down and bottom‐up forces

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    Salt marshes dominated by saline seepweed (Suaeda heteroptera) provide important ecosystem services such as sequestering carbon (blue carbon), maintaining healthy fisheries, and protecting shorelines. These salt marshes also constitute stunning red beach landscapes, and the resulting tourism significantly contributes to the local economy. However, land use change and degradation have led to a substantial loss of the red beach area. It remains unclear how human activities influence the top‐down and bottom‐up forces that regulate the distribution and succession of these salt marshes and lead to the degradation of the red beaches. We examined how bottom‐up forces influenced the germination, emergence, and colonization of saline seepweed with field measurements and a laboratory experiment. We also examined whether top‐down forces affected the red beach distribution by conducting a field survey for crab burrows and density, laboratory feeding trials, and waterbird investigations. The higher sediment accretion rate induced by human activities limited the establishment of new red beaches. The construction of tourism facilities and the frequent presence of tourists reduced the density of waterbirds, which in turn increased the density of crabs, intensifying the top‐down forces such as predators and herbivores that drive the degradation of the coastal red beaches. Our results show that sediment accretion and plant–herbivory changes induced by human activities were likely the two primary ecological processes leading to the degradation of the red beaches. Human activities significantly shaped the abundance and distribution of the red beaches by altering both top‐down and bottom‐up ecological processes. Our findings can help us better understand the dynamics of salt marshes and have implications for the management and restoration of coastal wetlands

    The compensational boundary method to calculate the projected contact area of nanoindentation in atomistic simulations

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    The atomistic simulation of nanoidentation has become a powerful method to probe the mechanical behaviour and properties of small volumes of materials. It is crucial to calculate the projected contact area (PCA) accurately in order to obtain a reliable value of nanoindentation hardness. In this work, atomistic simulations of nanoindentation were performed on the Cu(111) and Ag(111) surfaces, and a new compensational boundary method is proposed to calculate the PCA. Compared with other available methods, this method provides a clear physical implication, and works well independently of the contact depth and the deformation behaviour of the material. It is also concluded that the widely-used experimental Oliver–Pharr (O–P) method significantly underestimates the PCA in atomistic simulations, and does not work for shallow nanoindentation at the nanoscale

    Live-Cell Bioorthogonal Chemical Imaging: Stimulated Raman Scattering Microscopy of Vibrational Probes

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    Innovations in light microscopy have tremendously revolutionized the way researchers study biological systems with subcellular resolution. In particular, fluorescence microscopy with the expanding choices of fluorescent probes has provided a comprehensive toolkit to tag and visualize various molecules of interest with exquisite specificity and high sensitivity. Although fluorescence microscopy is currently the method of choice for cellular imaging, it faces fundamental limitations for studying the vast number of small biomolecules. This is because common fluorescent labels, which are relatively bulky, could introduce considerable perturbation to or even completely alter the native functions of vital small biomolecules. Hence, despite their immense functional importance, these small biomolecules remain largely undetectable by fluorescence microscopy. To address this challenge, a bioorthogonal chemical imaging platform has recently been introduced. By coupling stimulated Raman scattering (SRS) microscopy, an emerging nonlinear Raman microscopy technique, with tiny and Raman-active vibrational probes (e.g., alkynes and stable isotopes), bioorthogonal chemical imaging exhibits superb sensitivity, specificity, and biocompatibility for imaging small biomolecules in live systems. In this Account, we review recent technical achievements for visualizing a broad spectrum of small biomolecules, including ribonucleosides and deoxyribonucleosides, amino acids, fatty acids, choline, glucose, cholesterol, and small-molecule drugs in live biological systems ranging from individual cells to animal tissues and model organisms. Importantly, this platform is compatible with live-cell biology, thus allowing real-time imaging of small-molecule dynamics. Moreover, we discuss further chemical and spectroscopic strategies for multicolor bioorthogonal chemical imaging, a valuable technique in the era of “omics”. As a unique tool for biological discovery, this platform has been applied to studying various metabolic processes under both physiological and pathological states, including protein synthesis activity of neuronal systems, protein aggregations in Huntington disease models, glucose uptake in tumor xenografts, and drug penetration through skin tissues. We envision that the coupling of SRS microscopy with vibrational probes would do for small biomolecules what fluorescence microscopy of fluorophores has done for larger molecular species
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