9,624 research outputs found

    Twist-3 contribution to the pion electromagnetic form factor

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    Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced significantly due to bound state effect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor mπ2/m0\sim m_\pi^2/m_0 with mπm_\pi being the pion meson mass and m0m_0 being the mean u- and d-quark masses). Consequently, although it is suppressed by the factor 1/Q21/Q^2, the twist-3 contribution is comparable with and even larger than the leading twist (twist-2) contribution at intermediate energy region of Q2Q^2 being 240GeV22 \sim 40 {GeV}^2.Comment: 10 pages, 2 fgures, latex. More discussions on the Sudakov effect added, references added. To appear in European Physical Journal C (Zeitschrift fur Physik C

    Find a Reasonable Ending for Stories: Does Logic Relation Help the Story Cloze Test?

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    Natural language understanding is a challenging problem that covers a wide range of tasks. While previous methods generally train each task separately, we consider combining the cross-task features to enhance the task performance. In this paper, we incorporate the logic information with the help of the Natural Language Inference (NLI) task to the Story Cloze Test (SCT). Previous work on SCT considered various semantic information, such as sentiment and topic, but lack the logic information between sentences which is an essential element of stories. Thus we propose to extract the logic information during the course of the story to improve the understanding of the whole story. The logic information is modeled with the help of the NLI task. Experimental results prove the strength of the logic information.Comment: Student Abstract in AAAI-201

    7-ketocholesterol stimulates differentiation of lens epithelial cells

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    PURPOSE: To establish if oxysterols stimulate differentiation of lens epithelial cells (LEC). METHODS: Primary cultures of lens epithelial cells were incubated with 7-ketocholesterol (7-keto), 25-hydroxycholesterol (25-OH) or cholesterol at 10 microg/ml for 10 days. Cells incubated with 100 ng/ml basic fibroblast growth factor (b-FGF) were used as positive controls for differentiation. The expression of the differentiation marker p57KIP2, proliferation marker PCNA (Proliferating Cell Nuclear Antigen) and fibers specific proteins gamma-crystallin, CP49, MIP26 following treatment with oxysterols was determined by western blot. Differentiation into fiber cells was further confirmed by counting the number of lentoid bodies formed following incubation with 7-keto. RESULTS: LEC incubated with 7-keto presented higher levels of p57KIP2 and showed expression of fiber specific proteins such as MIP26 and CP49, compared to cells incubated with 25-OH or cholesterol. The differentiation marker p57KIP2 increased over time for cells incubated with 7-keto while there was a decline on the amount of the proliferation marker PCNA. The expression of the fiber specific proteins gamma-crystallin, MIP26 and CP49 was detected after 5 days of incubation with 7-keto. Differentiation was accompanied by a seven-fold increase in the number of lentoid bodies formed. CONCLUSIONS: Results show for the first time that 7-keto inhibits proliferation and stimulates differentiation of lens epithelial cells into fiber cells. The presence of 7-keto in the lens may disrupt the highly regulated differentiation program of LEC, compromising normal lens growth and transparenc

    Inverse scattering procedures for the reconstruction of one-dimensional permittivity range profile

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    In the present work we have presented a reliable and efficient algorithm for the data inversion, which is based on a fully nonlinear data model in conjunction with an optimization technique. The reconstruction of the permittivity range profile has been tested both on synthetic and real data to validate the electromagnetic code as well as to assess the accuracy and efficiency of the reconstruction procedure. We have studied the resolution of the algorithm and its robustness to the noise, demonstrating the ability of our procedure to be able to recognize the presence of high discontinuities even independently from the discretization fixed by the user. As a part of the ongoing improvement of the presented method, we have addressed the implementation of a new optimization algorithm, namely the particle swarm optimization, which has been customized and enhanced for our purposes. Finally, a detailed description of a fast and efficient procedure to evaluate the green’s function for a multilayered medium has been given. This is the groundwork useful for the next step toward a more reliable and versatile forward solver to be implemented in the inversion procedure

    Order-Free RNN with Visual Attention for Multi-Label Classification

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    In this paper, we propose the joint learning attention and recurrent neural network (RNN) models for multi-label classification. While approaches based on the use of either model exist (e.g., for the task of image captioning), training such existing network architectures typically require pre-defined label sequences. For multi-label classification, it would be desirable to have a robust inference process, so that the prediction error would not propagate and thus affect the performance. Our proposed model uniquely integrates attention and Long Short Term Memory (LSTM) models, which not only addresses the above problem but also allows one to identify visual objects of interests with varying sizes without the prior knowledge of particular label ordering. More importantly, label co-occurrence information can be jointly exploited by our LSTM model. Finally, by advancing the technique of beam search, prediction of multiple labels can be efficiently achieved by our proposed network model.Comment: Accepted at 32nd AAAI Conference on Artificial Intelligence (AAAI-18

    The effects of viscosity on the circumplanetary disks

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    The effects of viscosity on the circumplanetary disks residing in the vicinity of protoplanets are investigated through two-dimensional hydrodynamical simulations with the shearing sheet model. We find that viscosity can affect properties of the circumplanetary disk considerably when the mass of the protoplanet is Mp33MM_p \lesssim 33M_\oplus, where MM_\oplus is the Earth mass. However, effects of viscosity on the circumplanetary disk are negligibly small when the mass of the protoplanet Mp33MM_p \gtrsim 33M_\oplus. We find that when Mp33MM_p \lesssim 33M_\oplus, viscosity can disrupt the spiral structure of the gas around the planet considerably and make the gas smoothly distributed, which makes the torques exerted on the protoplanet weaker. Thus, viscosity can make the migration speed of a protoplanet lower. After including viscosity, size of the circumplanetary disk can be decreased by a factor of 20\gtrsim 20%. Viscosity helps to transport gas into the circumplanetary disk from the differentially rotating circumstellar disk. The mass of the circumplanetary disk can be increased by a factor of 50% after viscosity is taken into account when Mp33MM_p \lesssim 33M_\oplus. Effects of viscosity on the formation of planets and satellites are briefly discussed.Comment: 17 pages, 8 figures; accepted by RA

    Rapid Amygdala Kindling Causes Motor Seizure and Comorbidity of Anxiety- and Depression-Like Behaviors in Rats

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    Amygdala kindling is a model of temporal lobe epilepsy (TLE) with convulsion. The rapid amygdala kindling has an advantage on quick development of motor seizures and for antiepileptic drugs screening. The rapid amygdala kindling causes epileptogenesis accompanied by an anxiolytic response in early isolation of rat pups or depressive behavior in immature rats. However, the effect of rapid amygdala kindling on comorbidity of anxiety- and depression-like behaviors is unexplored in adult rats with normal breeding. In the present study, 40 amygdala stimulations given within 2 days were applied in adult Wistar rats. Afterdischarge (AD) and seizure stage were recorded throughout the amygdala kindling. Anxiety-like behaviors were evaluated by the elevated plus maze (EPM) test and open field (OF) test, whereas depression-like behaviors were assessed by the forced swim (FS) and sucrose consumption (SC) tests. A tonic-clonic convulsion was provoked in the kindle group. Rapid amygdala kindling resulted in a significantly lower frequency entering an open area of either open arms of the EPM or the central zone of an OF, lower sucrose intake, and longer immobility of the FS test in the kindle group. Our results suggest that rapid amygdala kindling elicited severe motor seizures comorbid with anxiety- and depression-like behaviors
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