2,862 research outputs found
Lecture Notes on Generalized Symmetries and Applications
In this lecture note, we give a basic introduction to the rapidly developing
concepts of generalized symmetries, from the perspectives of both high energy
physics and condensed matter physics. In particular, we emphasize on the
(invertible) higher-form and higher-group symmetries. For the physical
applications, we discuss the geometric engineering of QFTs in string theory and
the symmetry-protected topological (SPT) phases in condensed matter physics.
The lecture note is based on a short course on generalized symmetries,
jointly given by Yi-Nan Wang and Qing-Rui Wang in Feb. 2023, which took place
at School of Physics, Peking University
(https://indico.ihep.ac.cn/event/18796/).Comment: 70 pages, Invited contribution for the Special Issue "Symmetry and
Chaos in Quantum Mechanics" for Symmetry (Ed. Dr. Cheng Peng
Relationship between Successive Flares in the Same Active Region and Space-Weather HMI Active Region Patch (SHARP) Parameters
A solar active region (AR) may produce multiple notable flares during its
passage across the solar disk. We investigate successive flares from
flare-eruptive active regions, and explore their relationship with solar
magnetic parameters. We examine six ARs in this study, each with at least one
major flare above X1.0. The Space-Weather HMI Active Region Patch (SHARP) is
employed in this study to parameterize the ARs. We aim to identify the most
flare-related SHARP parameters and lay foundation for future practical flare
forecasts. We first evaluate the correlation coefficients between the SHARP
parameters and the successive flare production. Then we adopt a Natural
Gradient Boost (NGBoost) method to analyze the relationship between the SHARP
parameters and the successive flare bursts. Based on the correlation analysis
and the importance distribution returned from NGBoost, we select 8 most
flare-related SHARP parameters. Finally, we discuss the physical meanings of
the 8 selected parameters and their relationship with flare production.Comment: 18 pages; 9 figures; Accepted for publication in Ap
DUET: A Generic Framework for Finding Special Quadratic Elements in Data Streams
Finding special items, like heavy hitters, top-k, and persistent items, has always been a hot issue in data stream processing for web analysis. While data streams nowadays are usually high-dimensional, most prior works focus on special items according to a certain primary dimension and yield little insight into the correlations between dimensions. Therefore, we propose to find special quadratic elements to reveal close correlations. Based on the items mentioned above, we extend our problem to three applications related to heavy hitters, top-k, and persistent items, and design a generic framework DUET to process them. Besides, we analyze the error bound of our algorithm and conduct extensive experiments on four data sets. Our experimental results show that DUET can achieve 3.5 times higher throughput and three orders of magnitude lower average relative error compared with cutting-edge algorithms
Scoulerine promotes cytotoxicity and attenuates stemness in ovarian cancer by targeting PI3K/AKT/mTOR axis
In women, ovarian cancer is a common gynecological cancer associated with poor prognosis, reoccurrence and chemoresistance. Scoulerine, a benzylisoquinoline alkaloid, has been reported effective against several carcinomas. Thus, we investigated the impact of scoulerine on ovarian cancer cells (OVCAR3). Cell viability was assessed by MTT assay, migration was determined by Boyden Chamber assay, while the invasion was monitored by Boyden Chamber assay using the matrigel. The stemness properties of OVCAR3 cells were observed by tumorsphere assay. Epithelial to mesenchymal transition (EMT) and stemness-related protein markers were monitored by real-time PCR analysis and immunoblotting. Scoulerine inhibits the viability of OVCAR3 cells with the IC50 observed at 10 µmol L–1 after 48 h treatment. Scoulerine inhibited the colony-forming ability, migration and invasiveness of OVCAR3 cells in a dose-dependent fashion. Scoulerine treatment also drastically reduced the spheroid-forming ability of OVCAR3 cells. The mesenchymal and stemness-related markers like N-cadherin, vimentin, CD-44, Oct-4, Sox-2 and Aldh1A1 were downregulated, whereas the epithelial markers like E-cadherin and CD-24 were upregulated in scoulerine-treated cells. The upstream PI3K/Akt/mTOR-axis was downregulated in scoulerine-treated cells. We concluded that scoulerine successfully perturbs the cancerous properties of OVCAR3 cells by targeting the PI3K/Akt/mTOR axis. In vivo studies revealed a substantial decrease in tumor mass and volume after scoulerine treatment. Furthermore, scoulerine treatment was found to decrease oxidative stress factors in ovarian cancer mice model. Scoulerine is a potential anticancer agent against ovarian cancer and can be considered as a lead molecule for this malignancy, provided further investigations are performed
Pluralistic Aging Diffusion Autoencoder
Face aging is an ill-posed problem because multiple plausible aging patterns
may correspond to a given input. Most existing methods often produce one
deterministic estimation. This paper proposes a novel CLIP-driven Pluralistic
Aging Diffusion Autoencoder (PADA) to enhance the diversity of aging patterns.
First, we employ diffusion models to generate diverse low-level aging details
via a sequential denoising reverse process. Second, we present Probabilistic
Aging Embedding (PAE) to capture diverse high-level aging patterns, which
represents age information as probabilistic distributions in the common CLIP
latent space. A text-guided KL-divergence loss is designed to guide this
learning. Our method can achieve pluralistic face aging conditioned on
open-world aging texts and arbitrary unseen face images. Qualitative and
quantitative experiments demonstrate that our method can generate more diverse
and high-quality plausible aging results.Comment: Accepted by ICCV 202
Topic-independent modeling of user knowledge in informational search sessions
Web search is among the most frequent online activities. In this context, widespread informational queries entail user intentions to obtain knowledge with respect to a particular topic or domain. To serve learning needs better, recent research in the field of interactive information retrieval has advocated the importance of moving beyond relevance ranking of search results and considering a user’s knowledge state within learning oriented search sessions. Prior work has investigated the use of supervised models to predict a user’s knowledge gain and knowledge state from user interactions during a search session. However, the characteristics of the resources that a user interacts with have neither been sufficiently explored, nor exploited in this task. In this work, we introduce a novel set of resource-centric features and demonstrate their capacity to significantly improve supervised models for the task of predicting knowledge gain and knowledge state of users in Web search sessions. We make important contributions, given that reliable training data for such tasks is sparse and costly to obtain. We introduce various feature selection strategies geared towards selecting a limited subset of effective and generalizable features. © 2021, The Author(s)
Dramatic Changes in the Electronic Structure Upon Transition to the Collapsed Tetragonal Phase in CaFe2As2
We use angle-resolved photoemission spectroscopy (ARPES) and density
functional theory (DFT) calculations to study the electronic structure of
CaFeAs in previously unexplored collapsed tetragonal (CT) phase. This
unusual phase of the iron arsenic high temperature superconductors was hard to
measure as it exists only under pressure. By inducing internal strain, via the
post growth, thermal treatment of the single crystals, we were able to
stabilize the CT phase at ambient-pressure. We find significant differences in
the Fermi surface topology and band dispersion data from the more common
orthorhombic-antiferromagnetic or tetragonal-paramagnetic phases, consistent
with electronic structure calculations. The top of the hole bands sinks below
the Fermi level, which destroys the nesting present in parent phases. The
absence of nesting in this phase along with apparent loss of Fe magnetic
moment, are now clearly experimentally correlated with the lack of
superconductivity in this phase.Comment: 5 pages, 4 figures, accepted in PRB(RC
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