Characterizing Intermittency of 4-Hz Quasi-periodic Oscillation in XTE J1550-564 using Hilbert-Huang Transform

We present the time-frequency analysis results based on the Hilbert-Huang transform (HHT) for the evolution of a 4-Hz low-frequency quasi-periodic oscillation (LFQPO) around the black hole X-ray binary XTE J1550-564. The origin of LFQPOs is still debated. To understand the cause of the peak broadening, we utilized a recently developed time-frequency analysis, HHT, for tracking the evolution of the 4-Hz LFQPO from XTE J1550 564. By adaptively decomposing the ~4-Hz oscillatory component from the light curve and acquiring its instantaneous frequency, the Hilbert spectrum illustrates that the LFQPO is composed of a series of intermittent oscillations appearing occasionally between 3 Hz and 5 Hz. We further characterized this intermittency by computing the confidence limits of the instantaneous amplitudes of the intermittent oscillations, and constructed both the distributions of the QPO's high and low amplitude durations, which are the time intervals with and without significant ~4-Hz oscillations, respectively. The mean high amplitude duration is 1.45 s and 90% of the oscillation segments have lifetimes below 3.1 s. The mean low amplitude duration is 0.42 s and 90% of these segments are shorter than 0.73 s. In addition, these intermittent oscillations exhibit a correlation between the oscillation's rms amplitude and mean count rate. This correlation could be analogous to the linear rms-flux relation found in the 4-Hz LFQPO through Fourier analysis. We conclude that the LFQPO peak in the power spectrum is broadened owing to intermittent oscillations with varying frequencies, which could be explained by using the Lense-Thirring precession model.Comment: 27 pages, 9 figures, accepted for publication in The Astrophysical Journa

Boosting Factual Consistency and High Coverage in Unsupervised Abstractive Summarization

Abstractive summarization has gained attention because of the positive performance of large-scale, pretrained language models. However, models may generate a summary that contains information different from the original document. This phenomenon is particularly critical under the abstractive methods and is known as factual inconsistency. This study proposes an unsupervised abstractive method for improving factual consistency and coverage by adopting reinforcement learning. The proposed framework includes (1) a novel design to maintain factual consistency with an automatic question-answering process between the generated summary and original document, and (2) a novel method of ranking keywords based on word dependency, where keywords are used to examine the coverage of the key information preserved in the summary. The experimental results show that the proposed method outperforms the reinforcement learning baseline on both the evaluations for factual consistency and coverage

Evaluation the activity of alveolar echinococcosis: A comparison between 18F-FDG PET and spectral CT

AbstractPurposeTo assess the iodine concentration of hepatic alveolar echinococcosis (HAE) using spectral computed tomography (CT) with comparison of [18F] fluorodeoxyglucose positron-emission tomography (18F-FDG PET), and to estimate the value of spectral CT for evaluation of HAE activity.Materials and methods18 patients with histologically confirmed or clinically proved HAE underwent spectral CT and 18F-FDG PET examinations. After three-phase scanning, the quantitative iodine-based material decomposition images and optimal monochromatic image of spectral CT were reconstructed and iodine concentration (IC) was measured in different organizational structures.Results18F-FDG PET identified increased metabolic activity in the corresponding lesions in 13 patients (13/18, 72.2%). The iodine concentration in marginal zone of lesion were significantly higher than in solid component of lesion and normal liver parenchyma during PVP and VP. The iodine value of edge tissue of the lesion and normal liver and iodine value of normal liver tissues showed statistically significant difference (P < 0.001). There was correlation between IC and SUVmax in marginal zone of HAE lesion, it was highest during PVP (r = 0.873, p < 0.001). There was low correlation between CT values and SUVmax.ConclusionThere was good correlation between spectral CT and 18F-FDG PET. Spectral CT could be recommended as a more practical tool in the clinical routine

Understanding the antecedents of consumer brand engagement by managing brand communities on social media

As social media provide companies with opportunities to create touch-points by enabling consumers to interact with brands in new ways, a key issue for organizations is how to use brand communities to engage customers and enhance their relationships with brands. Brand community interactivity is one of the latest developments to engage consumers in online brand communities. The objective of brand communities is not only to attract potential customers, but also to retain loyal consumers and gain advocates. Thus, brands and companies’ social media activity should be appropriately organized and managed for high-level consumer brand engagement (CBE), which is a comprehensive construct that allow companies to examine the bond between their brands and consumers. The essence of this CBE bond is related to the involvement of consumers, as it increases the touch-points between them and the brand. This study examined perceived interactivity as a driving factor in the context of a brand community on social media with the purpose of encouraging consumer community engagement, community satisfaction, and consumer brand engagement (CBE). Two second-order constructs were operationalized in the research model. Communication, responsiveness, and control were treated as reflective factors to create the second-order construct “perceived interactivity,” while the other second-order construct “CBE” comprised cognitive processing, affection, and activation as reflective indicators. The results, based on data collected from 328 social media users who are followers of a smartphone brand’s Facebook page, indicated that perceived interactivity is likely to significantly affect consumer community engagement and community satisfaction, which in turn foster brand engagement. Successful social media marketing practices for companies should take responsibility for transforming consumer community engagement into CBE, as it is imperative for organizations building brand communities to enhance their consumer community satisfaction through proper community management to achieve high CBE

Interaction induced ferro-electricity in the rotational states of polar molecules

We show that a ferro-electric quantum phase transition can be driven by the dipolar interaction of polar molecules in the presence a micro-wave field. The obtained ferro-electricity crucially depends on the harmonic confinement potential, and the resulting dipole moment persists even when the external field is turned off adiabatically. The transition is shown to be second order for fermions and for bosons of a smaller permanent dipole moment, but is first order for bosons of a larger moment. Our results suggest the possibility of manipulating the microscopic rotational state of polar molecules by tuning the trap's aspect ratio (and other mesoscopic parameters), even though the later's energy scale is smaller than the former's by six orders of magnitude.Comment: 4 pages and 4 figure

Boosting Convolution with Efficient MLP-Permutation for Volumetric Medical Image Segmentation

Recently, the advent of vision Transformer (ViT) has brought substantial advancements in 3D dataset benchmarks, particularly in 3D volumetric medical image segmentation (Vol-MedSeg). Concurrently, multi-layer perceptron (MLP) network has regained popularity among researchers due to their comparable results to ViT, albeit with the exclusion of the resource-intensive self-attention module. In this work, we propose a novel permutable hybrid network for Vol-MedSeg, named PHNet, which capitalizes on the strengths of both convolution neural networks (CNNs) and MLP. PHNet addresses the intrinsic isotropy problem of 3D volumetric data by employing a combination of 2D and 3D CNNs to extract local features. Besides, we propose an efficient multi-layer permute perceptron (MLPP) module that captures long-range dependence while preserving positional information. This is achieved through an axis decomposition operation that permutes the input tensor along different axes, thereby enabling the separate encoding of the positional information. Furthermore, MLPP tackles the resolution sensitivity issue of MLP in Vol-MedSeg with a token segmentation operation, which divides the feature into smaller tokens and processes them individually. Extensive experimental results validate that PHNet outperforms the state-of-the-art methods with lower computational costs on the widely-used yet challenging COVID-19-20 and Synapse benchmarks. The ablation study also demonstrates the effectiveness of PHNet in harnessing the strengths of both CNNs and MLP

An Enhanced Screenshot Interaction with Animated Stickers to Promote Learning Transfer

This study has implemented a platform, namely piniton.tw, rolling out a redesign of user interaction with screenshot. It is an excellent environment for students’ collaborative learning, as students upload screenshots and interact with each other to complete assignments by using animated stickers. As the study intended to investigate how to promote learning transfer by means of such enhanced screenshot interaction with animated stickers, task difficulty, online participation, and learning transfer were chosen as the basis for the research model. By applying the technology acceptance model, perceived ease of use, perceived usefulness, and behavioral intention were included. The results indicated that students’ perceived ease of use and perceived usefulness are likely to significantly affect their behavioral intention, which in turn promote learning transfer. An implication is that students’ learning transfer could be prompted greatly by enhancing their intention to use such platform that provides enhanced screenshot interaction with animated stickers