368 research outputs found

    OTS: A One-shot Learning Approach for Text Spotting in Historical Manuscripts

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    Historical manuscript processing poses challenges like limited annotated training data and novel class emergence. To address this, we propose a novel One-shot learning-based Text Spotting (OTS) approach that accurately and reliably spots novel characters with just one annotated support sample. Drawing inspiration from cognitive research, we introduce a spatial alignment module that finds, focuses on, and learns the most discriminative spatial regions in the query image based on one support image. Especially, since the low-resource spotting task often faces the problem of example imbalance, we propose a novel loss function called torus loss which can make the embedding space of distance metric more discriminative. Our approach is highly efficient and requires only a few training samples while exhibiting the remarkable ability to handle novel characters, and symbols. To enhance dataset diversity, a new manuscript dataset that contains the ancient Dongba hieroglyphics (DBH) is created. We conduct experiments on publicly available VML-HD, TKH, NC datasets, and the new proposed DBH dataset. The experimental results demonstrate that OTS outperforms the state-of-the-art methods in one-shot text spotting. Overall, our proposed method offers promising applications in the field of text spotting in historical manuscripts

    Realization of Two-Dimensional Spin-orbit Coupling for Bose-Einstein Condensates

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    Cold atoms with laser-induced spin-orbit (SO) interactions provide intriguing new platforms to explore novel quantum physics beyond natural conditions of solids. Recent experiments demonstrated the one-dimensional (1D) SO coupling for boson and fermion gases. However, realization of 2D SO interaction, a much more important task, remains very challenging. Here we propose and experimentally realize, for the first time, 2D SO coupling and topological band with 87^{87}Rb degenerate gas through a minimal optical Raman lattice scheme, without relying on phase locking or fine tuning of optical potentials. A controllable crossover between 2D and 1D SO couplings is studied, and the SO effects and nontrivial band topology are observed by measuring the atomic cloud distribution and spin texture in the momentum space. Our realization of 2D SO coupling with advantages of small heating and topological stability opens a broad avenue in cold atoms to study exotic quantum phases, including the highly-sought-after topological superfluid phases.Comment: 27 pages, 5 figure

    Probing Primordial Gravitational Waves: Ali CMB Polarization Telescope

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    In this paper, we will give a general introduction to the project of Ali CMB Polarization Telescope (AliCPT), which is a Sino-US joint project led by the Institute of High Energy Physics (IHEP) and has involved many different institutes in China. It is the first ground-based Cosmic Microwave Background (CMB) polarization experiment in China and an integral part of China's Gravitational Waves Program. The main scientific goal of AliCPT project is to probe the primordial gravitational waves (PGWs) originated from the very early Universe. The AliCPT project includes two stages. The first stage referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet with an altitude of 5,250 meters. Once completed, it will be the worldwide highest ground-based CMB observatory and open a new window for probing PGWs in northern hemisphere. AliCPT-1 telescope is designed to have about 7,000 TES detectors at 90GHz and 150GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with the number of detectors more than 20,000. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio rr by one order of magnitude with 3 years' observation. Besides the PGWs, the AliCPT will also enable a precise measurement on the CMB rotation angle and provide a precise test on the CPT symmetry. We show 3 years' observation will improve the current limit by two order of magnitude.Comment: 11 pages, 7 figures, 2 table

    Metagenomic and metaproteomic analyses of microbial amino acid metabolism during Cantonese soy sauce fermentation

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    Cantonese soy sauce is an important type of traditional Chinese brewed soy sauce that was developed in southern China, mainly in Guangdong. Due to the long fermentation period and complex microbiota in Cantonese soy sauce, there are few reports on the microbial metaproteomics of Cantonese soy sauce. In this study, integrative metagenomic and metaproteomic analyzes were used to identify the changes in the dominant microbiota and amino acid synthesis-related enzymes and metabolism during Cantonese soy sauce fermentation. Metagenomic analysis revealed that Tetragenococcus halophilus, Weissella confusa, Weissella paramesenteroides, Enterobacter hormaechei, and Aspergillus oryzae were the dominant microbiota. Using the Top 15 dominant microbiota identified by metagenomics as the database, LTQ Orbitrap Velos Pro ETD mass spectrometry was used to obtain metaproteomic information about the microbes in the soy sauce, and the results indicated that the active enzymes involved in the metabolism of amino acids were secreted by microorganisms such as A. oryzae, T. halophilus, and Zygosaccharomyces rouxii. During the Cantonese soy sauce fermentation process. Among them, early fermentation (0-15d) was dominated by A. oryzae and T. halophilus, mid-term fermentation (60-90d) was dominated by Z. rouxii, A. oryzae, and T. halophilus, and late fermentation (90-120d) was dominated by A. oryzae, Z. rouxii, and T. halophilus. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the main enzymes involved in the metabolism of umami amino acids were aspartate aminotransferase, citrate synthase, aconitase, and isocitrate dehydrogenase, which were produced by Z. rouxii and A. oryzae during early fermentation (0–15 d) and the middle fermentation stage (60–90 d). This study constructed a regulatory network of enzymes potentially involved in the metabolism of flavor amino acids, which provided a theoretical basis for studying the amino acid metabolism of Cantonese soy sauce

    Forecasts of CMB lensing reconstruction of AliCPT-1 from the foreground cleaned polarization data

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    Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we demonstrate CMB lensing reconstruction in AliCPT-1 after foreground removal, combine the two bands of AliCPT-1 (90 and 150~GHz) with Planck HFI bands (100, 143, 217 and 353~GHz) and with the WMAP-K band (23~GHz). In order to balance contamination by instrumental noise and foreground residual bias, we adopt the Needlet Internal Linear Combination (NILC) method to clean the E-map and the constrained Internal Linear Combination (cILC) method to clean the B-map. The latter utilizes additional constraints on average frequency scaling of the dust and synchrotron to remove foregrounds at the expense of somewhat noisier maps. Assuming 4 modules observing 1 season from simulation data, the resulting effective residual noise in E- and B-map are roughly 15 μKarcmin15~\mu{\rm K}\cdot{\rm arcmin} and 25 μKarcmin25~\mu{\rm K}\cdot{\rm arcmin}, respectively. As a result, the CMB lensing reconstruction signal-to-noise ratio (SNR) from polarization data is about SNR\,\approx\,4.5. This lensing reconstruction capability is comparable to that of other stage-III small aperture millimeter CMB telescopes.Comment: 12 pages, 6 figure

    cDNA cloning and sequence analysis of hepatitis G virus genome isolated from a Chinese blood donor

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    Objective To obtain full-length sequence of a Chinese hepatitis G virus (HGV) strain (HGVch) and investigate the genetic characteristic of HGVch and its identity to other isolates. Methods Reverse transcription (RT) and nested-PCR were used to screen HGV RNA positive serum and amplify cDNA fragments. A positive serum without known hepatitis virus markers was selected for isolating HGV RNA template. The HGV genome was divided into 12 overlapping fragments and directly cloned into pGEM-T vector. Sequences were determined by dideoxy terminus-end method of DNA sequencing and then analyzed by computer. Results The twelve fragments of HGVch cover 9213 nucleotides in length, containing a large opera reading frame (ORF) encoding 2873 animo acids polyprotein that began with a methonine residue and ended at termination codon. HGVch is about 86.5% - 89.5% identical to other known HGV isolates at the nucleotide level and about 93.9% - 96.2% at the deduced animo acid level. Conclusion HGV is a non-A-E hepatitis causal agent, proved to be related with posttransfusion hepatitis in all over the world. Chinese HGV isolate has very close relationship to other isolates from Africa, Europe, Japan, without significant difference across the entire genome. It is suggested that the sequences of HGV isolates are very conservative and the evolution is very slow
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