1,691 research outputs found
The long-range interactions between branes in diverse dimensions
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 D-brane and a
D-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 (D, D) bound state
is actually a marginal one.Comment: 28 pages, various discussions expanded and references adde
Test of conformal gravity with astrophysical observations
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 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
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
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
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
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 (DCo), 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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