检索结果-内蒙古大学图书馆

arXiv 2024年

作者： Pal, Sourav Samanta, Rickmoy Pal, Supratik Physics and Applied Mathematics Unit Indian Statistical Institute 203 B.T. Road Kolkata700108 India Department of Physics Birla Institute of Technology and Science Pilani Hyderabad500078 India

In the standard cosmological framework, neutrinos begin to free-stream after the weak interaction phase ends in the early universe, at a temperature of approximately T ∼ 1 MeV. However, the onset of neutrino free-streaming can be delayed if additional interactions occur in the early universe, leaving imprints on both the cosmic microwave background (CMB) angular power spectra and the large-scale structure (LSS) matter power spectra. We present a thorough analysis of early universe neutrino interactions with a fairly generalized parameterization of the interaction rates as a power law in neutrino temperature. In this (6+2) parameter scenario, we constrain the cosmological parameters along with the free-streaming redshift and the sum of the neutrino mass in presence of such interactions, with the help of full shape (FS) galaxy power spectra from BOSS data Release 12. Our analysis reveals that a combined dataset of FS along with CMB and BAO offers improved constraints on the free-streaming redshift from present data, comparable to the forecast results from future CMB-S4 data. Additionally, we investigate the prospects of future galaxy surveys by forecasting on Euclid mission in combination with Planck and CMB-S4, and find significant improvement on both the free-streaming redshift and the sum of the neutrino mass than the existing constraints as well as than CMB-S4 alone. Copyright © 2024, The Authors. All rights reserved.

关键词： Cosmology

来源：评论

学校读者我要写书评

暂无评论

Mutual Contrastive Low-rank Learning to Disentangle Whole Slide Image Representations for Glioma Grading 33

Mutual Contrastive Low-rank Learning to Disentangle Whole Sl...

引用

33rd British Machine Vision Conference Proceedings, BMVC 2022

作者： Zhang, Lipei Wei, Yiran Fu, Ying Price, Stephen Schönlieb, Carola-Bibiane Li, Chao Department of Applied Mathematics and Theoretical Physics University of Cambridge United Kingdom Department of Clinical Neuroscience University of Cambridge United Kingdom School of Computer Science and Technology Beijing Institute of Technology China

Whole slide images (WSI) provide valuable phenotypic information for histological assessment and malignancy grading of tumors. The WSI-based grading promises to provide rapid diagnostic support and facilitate digital health. Currently, the most commonly used WSIs are derived from formalin-fixed paraffin-embedded (FFPE) and Frozen section. The majority of automatic tumor grading models are developed based on FFPE sections, which could be affected by the artifacts introduced from tissue processing. The frozen section exists problems such as low quality that might influence training within single modality as well. To overcome these problems in the single modal training and achieve better multi-modal and discriminative representation disentanglement in brain tumor, we propose a mutual contrastive low-rank learning (MCL) scheme to integrate FFPE and frozen sections for glioma grading. We first design a mutual learning scheme to jointly optimize the model training based on FFPE and frozen sections. In this proposed scheme, we design a normalized modality contrastive loss (NMC-loss), which could promote to disentangle multi-modality complementary representation of FFPE and frozen sections from the same patient. To reduce intra-class variance, and increase inter-class margin at intra- and inter-patient levels, we conduct a low-rank (LR) loss. Our experiments show that the proposed scheme achieves better performance than the model trained based on each single modality or mixed modalities without reducing the efficiency of inference, and even improves the feature extraction in classical attention-based multiple instances learning methods (MIL). The combination of NMC-loss and low-rank loss outperforms other typical contrastive loss functions. The source code is in https://***/uceclz0/MCL_glioma_grading. © 2022. The copyright of this document resides with its authors. It may be distributed unchanged freely in print or electronic forms.

关键词： Grading

来源：评论

学校读者我要写书评

暂无评论

Lithium and Beryllium Isotopes in the PAMELA Experiment

引用

Bulletin of the Russian Academy of sciences: physics 2023年第7期87卷 863-866页

作者： Bogomolov, E.A. Vasilyev, G.I. Menn, W. Adriani, O. Bazilevskaya, G.A. Barbarino, G.C. Bellotti, R. Boezio, M. Bonvicini, V. Bongi, M. Bottai, S. Bruno, A. Vacchi, A. Vannuccini, E. Voronov, S.A. Galper, A.M. De Santis, C. Di Felice, V. Zampa, G. Zampa, N. Casolino, M. Campana, D. Carlson, P. Castellini, G. Cafagna, F. Kvashnin, A.A. Kvashnin, A.N. Koldobskiy, S.A. Lagoida, I.A. Leonov, A.A. Mayorov, A.G. Malakhov, V.V. Martucci, M. Marcelli, L. Merge, M. Mikhailov, V.V. Mocchiutti, E. Monaco, A. Mori, N. Munini, R. Osteria, G. Panico, B. Papini, P. Picozza, P. Ricci, M. Ricciarini, S.B. Simon, M. Sparvoli, R. Spillantini, P. Stozhkov, Y.I. Yurkin, Y.T. Ioffe Institute Russian Academy of Sciences St. Petersburg194021 Russia University of Siegen Siegen57068 Germany Department of Physics University of Florence Florence50019 Italy Branch of Florence National Institute for Nuclear Physics Florence50019 Italy Lebedev Physical Institute Russian Academy of Sciences Moscow119991 Russia Department of Physics University of Naples "Federico II" Naples80126 Italy Branch of Naples National Institute for Nuclear Physics Naples80126 Italy Department of Physics University of Bari Bari70126 Italy Branch of Bari National Institute for Nuclear Physics Bari70126 Italy Moscow115409 Russia Branch of Trieste National Institute for Nuclear Physics Trieste34149 Italy Department of Mathematics and Informatics University of Udine Udine33100 Italy "Tor Vergata" Branch of Rome National Institute for Nuclear Physics Rome00133 Italy Department of Physics University of Rome Tor Vergata Rome00133 Italy Science Data Center Italian Space Agency Rome00133 Italy Department of Physics and the Oskar Klein Centre for Cosmoparticle Physics AlbaNova University Centre KTH Royal Institute of Technology Stockholm10691 Sweden Institute for Applied Physics Nello Carrara Florence50019 Italy Frascati National Laboratory National Institute for Nuclear Physics Frascati00044 Italy Department of Physics University of Trieste Trieste34147 Italy

Abstract: The isotopic composition of Li and Be nuclei in the 1–5 GV range of rigidities (nuclear energies of 0.1–1.5 GeV/nucleon) is analyzed using PAMELA flight data from 2006–2014 on the rigidity of detected nuclei and their velocities (time-of-flight analysis and ionization losses in the detector’s multilayer calorimeter). The new PAMELA data expand the range of energies in earlier measurements, are consistent with scarce results, and indicate correlated deviations of Li and Be isotope ratios from the GALPROP data for GCRs, which can be interpreted as evidence of contributions from several nearby local sources against the GCR background. Analysis of precision AMS-02 data on the spectra of positrons, antiprotons, and secondary nuclei of Li, Be, and B also indicates correlated increases in intensity at rigidities of ~50–1000 GV, which could also be due to local sources. The contribution from local sources against the GCR background is estimated at levels of tens of percents for rigidities of 1–5 GV and several percent at rigidities of 50–1000 GV. © 2023, Allerton Press, Inc.

关键词： Rigidity

来源：评论

学校读者我要写书评

暂无评论

Primordial Gravitational Waves as Probe of Dark Matter in Interferometer Missions: Fisher Forecast and MCMC

arXiv

引用

arXiv 2024年

作者： Ghoshal, Anish Paul, Debarun Pal, Supratik Institute of Theoretical Physics Faculty of Physics University of Warsaw ul. Pasteura 5 Warsaw02-093 Poland Physics and Applied Mathematics Unit Indian Statistical Institute 203 B.T. Road Kolkata700108 India Technology Innovation Hub on Data Science Big Data Analytics and Data Curation Indian Statistical Institute 203 B.T. Road Kolkata700108 India

We propose novel inflationary primordial gravitational wave (GW) spectral shapes at interferometer-based current and future GW missions to test dark matter (DM) production via gravity-portal. We consider three right-handed neutrinos (RHNs), required to generate Standard Model (SM) neutrino masses via seesaw mechanism, are produced via gravity-portal in early universe. The lightest among them is stable and is the DM candidate of the Universe. The other two RHNs decay and generate matter-antimatter asymmetry due to baryogenesis via leptogenesis. We find that future GW detectors BBO, DECIGO, ET, for instance, are able to probe DM mass for 5 × 106 GeV DM 7 GeV with a signal-to-noise ratio (SNR) > 10, along with the observed amount of baryon asymmetry due to gravitational leptogenesis for heavy RHN mass MN to be around 8 × 1012 GeV. Employing Fisher matrix forecast analysis, we identify the parameter space involving nonminimal coupling to gravity ξ, reheating temperature of the Universe Trh and DM mass MDM where the GW detector-sensitivities will be the maximum with the least error, along with SNR > 10. Finally, utilizing mock data for each GW detector, we perform MCMC analysis to find out the combined constraints on the various microphysics parameters. We also explore production of other cosmological relics such as QCD axion relic as DM candidate, produced via gravity-portal in early universe. We find that ET, for instance, can probe the decay constant of such DM candidates (fa) as 109 GeV fa 1014 GeV for misalignment angle θi ∈ [0.1, π/√3] and ξ = 1 with SNR > 10, whereas this range decreases with the increase of non-minimal coupling. Thus the upcoming GW missions will be able to test such nonthermal DM and baryogenesis scenarios involving very high energy scales, which is otherwise impossible to reach in particle physics experiments in laboratories. Copyright © 2024, The Authors. All rights reserved.

关键词： Signal to noise ratio

来源：评论

学校读者我要写书评

暂无评论

Monte Carlo physics-informed neural networks for multiscale heat conduction via phonon Boltzmann transport equation

arXiv

引用

arXiv 2024年

作者： Lin, Qingyi Zhang, Chuang Meng, Xuhui Guo, Zhaoli Institute of Interdisciplinary Research for Mathematics and Applied Science School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan430074 China Department of Physics School of Sciences Hangzhou Dianzi University Hangzhou310018 China

The phonon Boltzmann transport equation (BTE) is widely used for the description of multiscale heat conduction (from nm to µm or mm) in solid materials. Developing numerical approaches to solve this equation is challenging since it is a 7-dimensional integral-differential equation. In this work, we propose the Monte Carlo physics-informed neural networks (MC-PINNs), which do not suffer from the "curse of dimensionality", to solve the phonon Boltzmann transport equation for modeling the multiscale heat conduction in solid materials. In MC-PINNs, we utilize a deep neural network to approximate the solution to the BTE and encode the BTE as well as the corresponding boundary/initial conditions using the automatic differentiation. In addition, we propose a novel two-step sampling approach to address the issues of inefficiency and inaccuracy in the widely used sampling methods in PINNs. In particular, we first randomly sample a certain number of points in the temporal-spatial space (Step I) and then draw another number of points randomly in the solid angular space (Step II). The training points at each step are constructed based on the data drawn from the above two steps using the tensor product. The two-step sampling strategy enables the MC-PINNs (1) to model the heat conduction from ballistic to diffusive regimes, and (2) to be more memory efficient compared to the conventional numerical solvers or existing PINNs for BTE. A series of numerical examples including quasi-one-dimensional (quasi-1D) steady/unsteady heat conduction in a film, and the heat conduction in quasi-two- and three-dimensional square domains, are conducted to justify the effectiveness of the MC-PINNs for heat conduction spanning diffusive and ballistic regimes. Finally, we perform a comparison on the computational time and the memory usage between the MC-PINNs and one of the state-of-the-art numerical methods to demonstrate the potential of MC-PINNs for large-scale problems in real-world applications.

关键词： Monte Carlo methods

来源：评论

学校读者我要写书评

暂无评论

Exploring homogeneous ice nucleation through molecular dynamics simulations with ab initio accuracy

引用

Physical Review B 2025年第13期111卷 134116-134116页

作者： Mingyi Chen Lin Tan Han Wang Linfeng Zhang Haiyang Niu State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing China HEDPS CAPT College of Engineering Peking University Beijing China DP Technology Beijing China AI for Science Institute Beijing China

Probing the homogeneous ice nucleation process from scratch at the molecular level is of great value but still experimentally unachievable. Previous theoretical simulations have found that ice originates from the low-mobile region with increasing abundance and persistence of tetrahedrally coordinated water molecules. However, a detailed microscopic picture of how the disordered hydrogen-bond network rearranges itself into an ordered network is still unclear. In this work, we use a deep neural network (DNN) model to “learn” the interatomic potential energy from quantum-mechanical data, thereby allowing for large-scale and long molecular dynamics simulations with ab initio accuracy. Using the forward flux sampling, a 36−µs-long simulation is performed to achieve complete homogeneous ice nucleation trajectories from scratch. We demonstrate that the nucleation mechanism and dynamics at the molecular resolution are deeply affected by the structural and dynamical heterogeneities in supercooled water. In distinct contrast to previous understanding, we find that ice formation occurs in coexisting high-mobile and low-mobile regions of supercooled water, with low-mobile, highly ordered regions first transforming into high-mobile regions before they crystallize into ice. Specifically, imperfectly coordinated (IC) water molecules with high mobility pave the way for the hydrogen-bond network rearrangement through the mechanisms of IC status transfer, annihilation, and generation, leading to the growth or shrinkage of the ice nucleus; the hydrogen-bond network formed by perfectly coordinated (PC) molecules stabilizes the nucleus, thus preventing it from vanishing and growing. Ice is born through competition and cooperation between IC and PC molecules. In the end, the nucleation rate at supercooling 46 K is calculated in a direct manner, and the result agrees well with experiments.

关键词： Quantum confinement

来源：评论

学校读者我要写书评

暂无评论

Solitons in Nonlinear Directional Couplers with Optical Metamaterials by Sine–Gordon Equation Approach

引用

Nonlinear Optics Quantum Optics 2022年第3-4期56卷 317-370页

作者： Yildirim, Yakup Biswas, Anjan Guggilla, Padmaja Khan, Salam Ekici, Mehmet Moraru, Luminita Triki, Houria Zayed, E.M.E. Alzahrani, Abdullah K. Belic, Milivoj R. Department of Mathematics Faculty of Arts and Sciences Near East University Nicosia99138 Cyprus Department of Physics Chemistry and Mathematics Alabama A&M University NormalAL35762–4900 United States Research Group Department of Mathematics King Abdulaziz University Jeddah21589 Saudi Arabia Department of Applied Mathematics National Research Nuclear University 31 Kashirskoe Hwy Moscow115409 Russia Department of Mathematics and Applied Mathematics Sefako Makgatho Health Sciences University Medunsa 0204 South Africa Department of Mathematics Faculty of Science and Arts Yozgat Bozok University Yozgat66100 Turkey Faculty of Sciences and Environment Department of Chemistry Physics and Environment Dunarea de Jos University of Galati 47 Domneasca Street 800008 Romania Radiation Physics Laboratory Department of Physics Faculty of Sciences Badji Mokhtar University P. O. Box 12 Annaba23000 Algeria Mathematics Department Faculty of Science Zagazig University Zagazig44519 Egypt Institute of Physics Belgrade Pregrevica 118 Zemun11080 Serbia

This paper recovers solitons with optical metamaterials in nonlinear directional couplers. Both twin–core and multiple–core couplers are considered. There are six nonlinear forms of refractive index studied. The sin... 详细信息

关键词： Solitons

来源：评论

学校读者我要写书评

暂无评论

Self-Driven Configurational Dynamics in Frustrated Spring-Mass Systems

arXiv

引用

arXiv 2023年

作者： Saporta-Katz, Ori Moriel, Avraham Computer Science and Applied Mathematics Department Weizmann Institute of Science Rehovot7610001 Israel Chemical and Biological Physics Department Weizmann Institute of Science Rehovot7610001 Israel

Various physical systems relax mechanical frustration through configurational rearrangements. We examine such rearrangements via Hamiltonian dynamics of simple internally-stressed harmonic 4-mass systems. We demonstrate theoretically and numerically how mechanical frustration controls the underlying potential energy landscape. Then, we examine the harmonic 4-mass systems' Hamiltonian dynamics and relate the onset of chaotic motion to self-driven rearrangements. We show such configurational dynamics may occur without strong precursors, rendering such dynamics seemingly spontaneous. © 2023, CC BY.

关键词： Dynamics

来源：评论

学校读者我要写书评

暂无评论

A new class of distances on complex projective spaces

引用

Linear Algebra and Its Applications 2025年 721卷 577-611页

作者： Bistroń, Rafal Eckstein, Michal Friedland, Shmuel Miller, Tomasz Życzkowski, Karol Institute of Theoretical Physics Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University ul. prof. Stanislawa Lojasiewicza 11 Krakow30-348 Poland Doctoral School of Exact and Natural Sciences Jagiellonian University ul. prof. Stanislawa Lojasiewicza 11 Krakow30-348 Poland Department of Mathematics Statistics and Computer Science University of Illinois at Chicago 851 S. Morgan Street ChicagoIL60607-7045 United States Copernicus Center for Interdisciplinary Studies Jagiellonian University ul. Mikolaja Kopernika 27 Krakow31-501 Poland Center for Theoretical Physics Polish Academy of Science aleja Lotników 32/46 Warsaw02-668 Poland

The complex projective space P(Cn) can be interpreted as the space of all quantum pure states of size n. A distance on this space, interesting from the perspective of quantum physics, can be induced from a classical distance defined on the n-point probability simplex by the ‘earth mover problem’. We show that this construction leads to a quantity satisfying the triangle inequality, which yields a true distance on complex projective space belonging to the family of quantum 2-Wasserstein distances. © 2024 Elsevier Inc.

关键词： State space methods

来源：评论

学校读者我要写书评

暂无评论

Polyp image segmentation based on improved planet optimization algorithm using reptile search algorithm

引用

Neural Computing and Applications 2025年第8期37卷 6327-6349页

作者： Abd Elaziz, Mohamed Al-qaness, Mohammed A. A. Al-Betar, Mohammed Azmi Ewees, Ahmed A. Department of Mathematics Faculty of Science Zagazig University Zagazig Egypt College of Physics and Electronic Information Engineering Zhejiang Normal University Jinhua321004 China Zhejiang Institute of Optoelectronics Jinhua321004 China Faculty of Computer Science and Engineering Galala University Suze435611 Egypt Ajman University Ajman346 United Arab Emirates College of Computing and Information Technology University of Bisha Bisha Saudi Arabia Department of Computer Damietta University Damietta Egypt Hourani Center for Applied Scientific Research Al-Ahliyya Amman University Amman Jordan

To recognize the potential for colon polyps to develop into cancer over time, early diagnosis is crucial for preventative healthcare. Timely identification significantly improves the prognosis and treatment outcomes for colorectal cancer patients. Image segmentation is crucial in medical image analysis for accurate diagnosis and treatment planning. Therefore, in this study, we present an alternative multilevel thresholding polyp segmentation method (MPOA) to enhance the segmentation of polyp images. The proposed method is based on enhancing the planet optimization algorithm (POA) by integrating operators from the reptile search algorithm (RSA). The evaluation of the developed MPOA is tested with different polyp images and compared with other image segmentation approaches. The results highlight the superior capability of MPOA, as evidenced by various performance measures in effectively segmenting polyp images. Furthermore, metrics such as peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and fitness values demonstrate that MPOA outperforms the basic version of POA and other methods. The evaluation outcomes underscore the significant impact of RSA in enhancing the performance of POA for the segmentation of polyp images. © The Author(s) 2025.

关键词： Diseases

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：