110 research outputs found

    Triangle mechanism in the decay process B0J/ψK0f0(980)(a0(980))B_0 \to J/\psi K^0 f_0(980)(a_0(980))

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    The role of the triangle mechanism in the decay process B0J/ψK0f0J/ψK0π+πB_0\to J/\psi K^0f_0 \to J/\psi K^0\pi^+\pi^- and B0JψK0a0J/ψK0π0ηB_0\to J\psi K^0a_0\to J/\psi K^0 \pi^0\eta is probed. In these process, the triangle singularity appears from the decay of B0B^0 into J/ψϕK0J/\psi\phi K^0 then ϕ\phi decays into K0K0ˉK^0\bar{K^0} and K0K0ˉK^0\bar{K^0} merged into f0f_0 or a0a_0 which finally decay into π+π\pi^+\pi^- and π0η\pi^0\eta respectively. We find that this mechanism leads to a triangle singularity around Minv(K0f0(a0))1520 MeVM_{\rm inv}(K^0f_0(a_0))\approx1520\ {\rm MeV}, and gives sizable branching fractions Br(B0J/ψK0f0J/ψK0π+π)=1.38×106{\rm{Br}}(B_0\to J/\psi K^0f_0\to J/\psi K^0\pi^+\pi^-)=1.38\times10^{-6} and Br(B0J/ψK0a0J/ψK0π0η)=2.56×107 {\rm{Br}}(B_0\to J/\psi K^0a_0\to J/\psi K^0\pi^0\eta)=2.56\times10^{-7}. This potential investigation can help us obtain the information of the scalar meson f0(980)f_0(980) or a0(980)a_0(980).Comment: 8 pages, 6 figure

    Pole determination of X(3960)X(3960) and X0(4140)X_0(4140) in decay B+K+Ds+DsB^+\to K^+D_s^+D_s^-

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    Two near-threshold peaking structures with spin-parities JPC=0++J^{PC}=0^{++} were recently discovered by the LHCb Collaboration in the Ds+DsD_s^+D_s^- invariant mass distribution of the decay process B+Ds+DsK+B^+\to D_s^+D_s^-K^+. In our study, we employed a coupled-channel model to fit the experimental results published by the LHCb collaboration, simultaneously fitting the model to the invariant mass distributions of MDs+DsM_{D_s^+D_s^-}, MDs+K+M_{D_s^+K^+}, and MDsK+M_{D_s^-K^+}. We utilized a coupled-channel model to search for the poles of X(3960)X(3960) and X0(4140)X_0(4140). The determination of the poles is meaningful in itself, and it also lays an foundation for the future research on X(3960)X(3960) and X0(4140)X_0(4140). Upon turning off the coupled-channel and performing another fit, we observed a change in the fitting quality, the effect was almost entirely due to the peak of X(3960)X(3960), so we suggest that X(3960)X(3960) may not be a kinematic effect.Comment: 6 pages, 7 figure

    Detecting Interference in A/B Testing with Increasing Allocation

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    In the past decade, the technology industry has adopted online randomized controlled experiments (a.k.a. A/B testing) to guide product development and make business decisions. In practice, A/B tests are often implemented with increasing treatment allocation: the new treatment is gradually released to an increasing number of units through a sequence of randomized experiments. In scenarios such as experimenting in a social network setting or in a bipartite online marketplace, interference among units may exist, which can harm the validity of simple inference procedures. In this work, we introduce a widely applicable procedure to test for interference in A/B testing with increasing allocation. Our procedure can be implemented on top of an existing A/B testing platform with a separate flow and does not require a priori a specific interference mechanism. In particular, we introduce two permutation tests that are valid under different assumptions. Firstly, we introduce a general statistical test for interference requiring no additional assumption. Secondly, we introduce a testing procedure that is valid under a time fixed effect assumption. The testing procedure is of very low computational complexity, it is powerful, and it formalizes a heuristic algorithm implemented already in industry. We demonstrate the performance of the proposed testing procedure through simulations on synthetic data. Finally, we discuss one application at LinkedIn, where a screening step is implemented to detect potential interference in all their marketplace experiments with the proposed methods in the paper

    Allopatric divergence and hybridization within Cupressus chengiana (Cupressaceae), a threatened conifer in the northern Hengduan Mountains of western China

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    Having a comprehensive understanding of population structure, genetic differentiation and demographic history is important for the conservation and management of threatened species. High‐throughput sequencing (HTS) provides exciting opportunities to address a wide range of factors for conservation genetics. Here, we generated HTS data and identified 266,884 high‐quality single nucleotide polymorphisms from 82 individuals of Cupressus chengiana , to assess population genomics across the species' full range, comprising the Daduhe River (DDH), Minjiang River (MJR) and Bailongjiang River (BLJ) catchments in western China. admixture , principal components analysis and phylogenetic analyses indicated that each region contains a distinct lineage, with high levels of differentiation between them (DDH, MJR and BLJ lineages). MJR was newly distinguished compared to previous surveys, and evidence including coalescent simulations supported a hybrid origin of MJR during the Quaternary. Each of these three lineages should be recognized as an evolutionarily significant unit (ESU), due to isolation, differing genetic adaptations and different demographic history. Currently, each ESU faces distinct threats, and will require different conservation strategies. Our work shows that population genomic approaches using HTS can reconstruct the complex evolutionary history of threatened species in mountainous regions, and hence inform conservation efforts, and contribute to the understanding of high biodiversity in mountains.Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 31622015Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 31590821Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 31370261Funding provided by: National Basic Research Program of China*Crossref Funder Registry ID: Award Number: 2014CB954100Funding provided by: Sichuan University Fundamental Research Funds for the Central Universities*Crossref Funder Registry ID: Award Number: SCU2019D013Funding provided by: Sichuan University Fundamental Research Funds for the Central Universities*Crossref Funder Registry ID: Award Number: SCU2018D006Funding provided by: National Basic Research Program of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100012166Award Number: 2014CB954100Funding provided by: Sichuan University Fundamental Research Funds for the Central UniversitiesCrossref Funder Registry ID: Award Number: SCU2019D013We identified 266,884 high-quality SNPs from 82 individuals to assess population genomics of Cupressus chengiana across its full range. To get a high-quality reference, single-molecule real-time (SMRT) sequencing was used to obtain the full-length transcriptome of C. chengiana. A total of 82 samples were collected for RNA-seq. We used bwa-mem to align the quality-filtered reads of each individual to the refences sequences. We used the "mpileup" command in SAMTOOLS to identify SNPs. Data were filtered with the following processes: SNPs with a mapping quality <30, a mapping depth <10, genotyping rate <50% per group, minor allele frequency (MAF) <5%, or in 5bps windows around any indel

    Learning to Evaluate Performance of Multi-modal Semantic Localization

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    Semantic localization (SeLo) refers to the task of obtaining the most relevant locations in large-scale remote sensing (RS) images using semantic information such as text. As an emerging task based on cross-modal retrieval, SeLo achieves semantic-level retrieval with only caption-level annotation, which demonstrates its great potential in unifying downstream tasks. Although SeLo has been carried out successively, but there is currently no work has systematically explores and analyzes this urgent direction. In this paper, we thoroughly study this field and provide a complete benchmark in terms of metrics and testdata to advance the SeLo task. Firstly, based on the characteristics of this task, we propose multiple discriminative evaluation metrics to quantify the performance of the SeLo task. The devised significant area proportion, attention shift distance, and discrete attention distance are utilized to evaluate the generated SeLo map from pixel-level and region-level. Next, to provide standard evaluation data for the SeLo task, we contribute a diverse, multi-semantic, multi-objective Semantic Localization Testset (AIR-SLT). AIR-SLT consists of 22 large-scale RS images and 59 test cases with different semantics, which aims to provide a comprehensive evaluations for retrieval models. Finally, we analyze the SeLo performance of RS cross-modal retrieval models in detail, explore the impact of different variables on this task, and provide a complete benchmark for the SeLo task. We have also established a new paradigm for RS referring expression comprehension, and demonstrated the great advantage of SeLo in semantics through combining it with tasks such as detection and road extraction. The proposed evaluation metrics, semantic localization testsets, and corresponding scripts have been open to access at github.com/xiaoyuan1996/SemanticLocalizationMetrics .Comment: 19 pages, 11 figure

    Across two phylogeographic breaks: Quaternary evolutionary history of a mountain aspen (Populus rotundifolia) in the Hengduan Mountains

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    Biogeographical barriers to gene flow are central to plant phylogeography. In East Asia, plant distribution is greatly influenced by two phylogeographic breaks, the Mekong-Salween Divide and Tanaka-Kaiyong Line, however, few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both. Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia, a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China. Demographic and migration hypotheses were tested using coalescent-based approaches. Limited historical gene flow was observed between the western and eastern groups of P. rotundifolia, but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line, manifesting in clear admixture and high genetic diversity in the central group. Wind-borne pollen and seeds may have facilitated the dispersal of P. rotundifolia following prevalent northwest winds in the spring. We also found that the Hengduan Mountains, where multiple genetic barriers were detected, acted on the whole as a barrier between the western and eastern groups of P. rotundifolia. Ecological niche modeling suggested that P. rotundifolia has undergone range expansion since the last glacial maximum, and demographic reconstruction indicated an earlier population expansion around 600 Ka. The phylogeographic pattern of P. rotundifolia reflects the interplay of biological traits, wind patterns, barriers, niche differentiation, and Quaternary climate history. This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas
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