3,024 research outputs found
Topological flat band with higher winding number in a superradiance lattice
A five-level M-type scheme in atomic ensembles is proposed to generate a
one-dimensional bipartite superradiance lattice in momentum space. By taking
advantage of this tunable atomic system, we show that various types of
Su-Schrieffer-Heeger (SSH) model, including the standard SSH and extended SSH
model, can be realized. Interestingly, it is shown that through changing the
Rabi frequencies and detunings in our proposed scheme, there is a topological
phase transition from topological trivial regime with winding number being 0 to
topological non-trivial regime with winding number being 2. Furthermore, a
robust flat band with higher winding number (being 2) can be achieved in the
above topological non-trivial regime, where the superradiance spectra can be
utilized as a tool for experimental detection. Our proposal would provide a
promising approach to explore new physics, such as fractional topological
phases, in the flat bands with higher topological number.Comment: 5 pages, 3 figure
Novel path curvature optimization algorithm for intelligent wheelchair to smoothly pass a narrow space
This paper presents a novel algorithm to address the smooth narrow pass traversing issue, which is based on optimizing the curvature of the wheelchair path. Being aware of the fact that the path smoothness is determined by the path curvature and its change rate, after calculating the position of the narrow pass relative to the base frame of the wheelchair from perception sensor data, the algorithm takes the curvature and its change rate of Bezier curve as the optimal objective, and the wheelchair heading and the condition that the Bezier curve polygon should be convex polygon as constraints, and plans a smooth and optimal path for the controlled wheelchair to follow. This process is iterated dynamically to enable the intelligent wheelchair to traverse the narrow pass smoothly. Simulation is firstly conducted to compare the performances of our method and the A*-based path planning navigation algorithm, which shows that the proposed algorithm is able to achieve more smooth path with smaller curvature when the wheelchair traverses narrow path. Furthermore, the algorithm can control the wheelchair to traverse narrow pass smoothly even without any global map and localization. Real experiment with detailed explanation of algorithm implementation is also given to verify the effectiveness of the proposed algorithm
1,4-Bis(dimethylÂsilyl)-2,5-diphenylÂbenzene
The molÂecule of the title compound, C22H26Si2, is centrosymmetric. The dihedral angle between the central benzene ring and its phenyl substituents is 67.7 (2)°. The crystal packing is stabilized by van der Waals forces
Self-Convinced Prompting: Few-Shot Question Answering with Repeated Introspection
While large language models (LLMs) such as ChatGPT and PaLM have demonstrated
remarkable performance in various language understanding and generation tasks,
their capabilities in complex reasoning and intricate knowledge utilization
still fall short of human-level proficiency. Recent studies have established
the effectiveness of prompts in steering LLMs towards generating desired
outputs. Building on these insights, we introduce a novel framework that
harnesses the potential of large-scale pre-trained language models, to
iteratively enhance performance of the LLMs. Our framework incorporates three
components: \textit{Normal CoT}, a \textit{Convincer}, and an
\textit{Answerer}. It processes the output of a typical few-shot
chain-of-thought prompt, assesses the correctness of the response, scrutinizes
the answer, refines the reasoning, and ultimately produces a new solution.
Experimental results on the 7 datasets of miscellaneous problems validate the
efficacy of the Self-Convince framework, achieving substantial improvements
compared to the baselines. This study contributes to the burgeoning body of
research focused on integrating pre-trained language models with tailored
prompts and iterative refinement processes to augment their performance in
complex tasks
Traffic Scheduling Strategy of Power Communication Network Based on SDN
Due to the complicated structure, power communication network is difficult to guarantee the quality of service (QoS) of power services. A two-level scheduling algorithm based on software defined network (SDN) is proposed in this paper. Firstly, the priority-based scheduling method is used to meet the latency-sensitive of power service. Then, in order to alleviate congestion, queue bandwidth is adjusted according to network state information, which can be collected by the centralized control of SDN. Finally, the Mininet and Ryu controller are made use of building simulation environment. The test results show that the algorithm proposed in this paper reduce delay and packet loss rate significantly, which achieves QoS
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Structural basis for DNMT3A-mediated de novo DNA methylation.
DNA methylation by de novo DNA methyltransferases 3A (DNMT3A) and 3B (DNMT3B) at cytosines is essential for genome regulation and development. Dysregulation of this process is implicated in various diseases, notably cancer. However, the mechanisms underlying DNMT3 substrate recognition and enzymatic specificity remain elusive. Here we report a 2.65-ångström crystal structure of the DNMT3A-DNMT3L-DNA complex in which two DNMT3A monomers simultaneously attack two cytosine-phosphate-guanine (CpG) dinucleotides, with the target sites separated by 14 base pairs within the same DNA duplex. The DNMT3A-DNA interaction involves a target recognition domain, a catalytic loop, and DNMT3A homodimeric interface. Arg836 of the target recognition domain makes crucial contacts with CpG, ensuring DNMT3A enzymatic preference towards CpG sites in cells. Haematological cancer-associated somatic mutations of the substrate-binding residues decrease DNMT3A activity, induce CpG hypomethylation, and promote transformation of haematopoietic cells. Together, our study reveals the mechanistic basis for DNMT3A-mediated DNA methylation and establishes its aetiological link to human disease
AlignDet: Aligning Pre-training and Fine-tuning in Object Detection
The paradigm of large-scale pre-training followed by downstream fine-tuning
has been widely employed in various object detection algorithms. In this paper,
we reveal discrepancies in data, model, and task between the pre-training and
fine-tuning procedure in existing practices, which implicitly limit the
detector's performance, generalization ability, and convergence speed. To this
end, we propose AlignDet, a unified pre-training framework that can be adapted
to various existing detectors to alleviate the discrepancies. AlignDet
decouples the pre-training process into two stages, i.e., image-domain and
box-domain pre-training. The image-domain pre-training optimizes the detection
backbone to capture holistic visual abstraction, and box-domain pre-training
learns instance-level semantics and task-aware concepts to initialize the parts
out of the backbone. By incorporating the self-supervised pre-trained
backbones, we can pre-train all modules for various detectors in an
unsupervised paradigm. As depicted in Figure 1, extensive experiments
demonstrate that AlignDet can achieve significant improvements across diverse
protocols, such as detection algorithm, model backbone, data setting, and
training schedule. For example, AlignDet improves FCOS by 5.3 mAP, RetinaNet by
2.1 mAP, Faster R-CNN by 3.3 mAP, and DETR by 2.3 mAP under fewer epochs.Comment: Accepted by ICCV 2023. Code and Models are publicly available.
Project Page: https://liming-ai.github.io/AlignDe
The Protective Effects of Curcumin on Obesity-Related Glomerulopathy Are Associated with Inhibition of Wnt/ β
The present study investigated the effects of curcumin, one of the most important active ingredients of turmeric, on podocyte injury in vitro and obesity-related glomerulopathy (ORG) in vivo. Cellular experiments in vitro showed that curcumin significantly antagonized leptin-induced downregulation of the mRNA and protein expression of podocyte-associated molecules including nephrin, podocin, podoplanin, and podocalyxin. Animal experiments in vivo showed that curcumin significantly reduced the body weight, Lee’s index, abdominal fat index, urinary protein excretion, and average glomerular diameter and significantly upregulated the mRNA and protein expressions of the above podocyte-associated molecules in ORG mice. Furthermore, the experiments in vitro and in vivo both displayed that curcumin could downregulate the mRNA and protein expressions of Wnt1, Wnt2b, Wnt6, and β-catenin and upregulate the phosphorylation level of β-catenin protein in podocytes and renal tissue. In conclusion, curcumin is able to alleviate the harmful reaction of leptin on podocytes and reduce the severity of ORG. The above protective effects are associated with the inhibition of Wnt/β-catenin signaling activation in podocytes
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