1,691 research outputs found

    The long-range interactions between branes in diverse dimensions

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    We calculate the long-range interactions between two simple branes placed parallel at a separation in diverse dimensions via an effective field theory approach. We also compute for the first time the explicit long-range interaction between two D-branes with each carrying a world-volume non-abelian magnetic flux in three special cases, respectively. In particular, we demonstrate that the half-string creation between a D0_0-brane and a D8_8-brane continues to hold even in the present context, therefore lending further support to the previous assertion of this. Our computations re-raise also the issue in one case on whether so constructed (D0_0, D8_8) bound state is actually a marginal one.Comment: 28 pages, various discussions expanded and references adde

    Test of conformal gravity with astrophysical observations

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    Since it can describe the rotation curves of galaxies without dark matter and can give rise to accelerated expansion, conformal gravity attracts much attention recently. As a theory of modified gravity, it is important to test conformal gravity with astrophysical observations. Here we constrain conformal gravity with SNIa and Hubble parameter data and investigate whether it suffers from an age problem with the age of APM~08279+5255. We find conformal gravity can accommodate the age of APM~08279+5255 at 3 σ\sigma deviation, unlike most of dark energy models which suffer from an age problem.Comment: 6 pages, 2 figure

    Rumor Clarification, Digital Platform, and Stock Movement

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    Stock return is influenced by information release, dissemination, and acceptance. Rumor clarification is supposed to reduce asymmetric information and abnormal stock return. In this research, we extracted 4134 rumor-clarification pairs from 687,429 postings in social media, and quantified the language used in these messages, along with online firm behaviors, to study the effect of clarifications on stock returns. Our findings include (1) the digitalized rumor clarification messages affect the abnormal returns of the relevant stocks; (2) Such influence can be quantified and measured by the emotion polarity of rumor clarification; (3) Firm’s online clarification behaviors may have no influence on abnormal returns except for the total response number of rumor clarification for a listed company. In particular, investors prefer to trust the clarifications from the companies with frequent online interactive engagements

    Investigation of the interaction between indigotin and two serum albumins by spectroscopic approaches

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    AbstractThe binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques. Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching. The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I. The thermodynamic parameters indicated that the binding of indigotin–HSA/BSA mainly depended on the hydrophobic interaction. The binding distance of indigotin to HSA/BSA was evaluated. The results by synchronous fluorescence, three-dimensional fluorescence, Fourier Transform Infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra showed that the conformation of proteins altered in the presence of indigotin

    Plant Age Effect on Mechanical Properties of Moso Bamboo (Phyllostachys Heterocycla Var. Pubescens) Single Fibers

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    Bamboo fiber has greater mechanical strength than certain other natural fibers and could therefore be a candidate for production of fiber-reinforced composites. Single fibers were isolated from Moso bamboo samples taken from plants between 0.5 and 8.5 yr old. Mechanical properties of single fibers (tensile strength, modulus of elasticity (MOE), and other mechanical related properties such as the microfibril angle and fiber cross-sectional area) were studied. There was no significant variation with age in average MOE and fracture strain of the bamboo fibers. Results indicate that the thickening growth of cell walls in bamboo fibers near the outer surface of bamboo is almost complete by 0.5 yr. Therefore, fibers from 0.5 to 8.5 yr old plants may be used for making fiber-reinforced composites

    Uncovering User Interest from Biased and Noised Watch Time in Video Recommendation

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    In the video recommendation, watch time is commonly adopted as an indicator of user interest. However, watch time is not only influenced by the matching of users' interests but also by other factors, such as duration bias and noisy watching. Duration bias refers to the tendency for users to spend more time on videos with longer durations, regardless of their actual interest level. Noisy watching, on the other hand, describes users taking time to determine whether they like a video or not, which can result in users spending time watching videos they do not like. Consequently, the existence of duration bias and noisy watching make watch time an inadequate label for indicating user interest. Furthermore, current methods primarily address duration bias and ignore the impact of noisy watching, which may limit their effectiveness in uncovering user interest from watch time. In this study, we first analyze the generation mechanism of users' watch time from a unified causal viewpoint. Specifically, we considered the watch time as a mixture of the user's actual interest level, the duration-biased watch time, and the noisy watch time. To mitigate both the duration bias and noisy watching, we propose Debiased and Denoised watch time Correction (D2^2Co), which can be divided into two steps: First, we employ a duration-wise Gaussian Mixture Model plus frequency-weighted moving average for estimating the bias and noise terms; then we utilize a sensitivity-controlled correction function to separate the user interest from the watch time, which is robust to the estimation error of bias and noise terms. The experiments on two public video recommendation datasets and online A/B testing indicate the effectiveness of the proposed method.Comment: Accepted by Recsys'2
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