5,127 research outputs found

    The Genus 0 Gromov-Witten Invariants of Projective Complete Intersections

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    We describe the structure of mirror formulas for genus 0 Gromov-Witten invariants of projective complete intersections with any number of marked points and provide an explicit algorithm for obtaining the relevant structure coefficients. The structural description alone suffices for some qualitative applications, such as vanishing results and the bounds on the growth of these invariants predicted by R. Pandharipande.Comment: two conjectures added; typos corrected 61 pages, 3 figures, 4 table

    Quantum Cohomology and Virasoro Algebra

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    We propose that the Virasoro algebra controls quantum cohomologies of general Fano manifolds MM (c1(M)>0c_1(M)>0) and determines their partition functions at all genera. We construct Virasoro operators in the case of complex projective spaces and show that they reproduce the results of Kontsevich-Manin, Getzler etc. on the genus-0,1 instanton numbers. We also construct Virasoro operators for a wider class of Fano varieties. The central charge of the algebra is equal to χ(M)\chi(M), the Euler characteristic of the manifold MM.Comment: latex,13pages. Revised version with a few typos correcte

    Analysis and Design of the Reconfiguration Motion Qualities of a Deformable Robot Based on a Metamorphic Mechanism

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    Traditional wheel-legged ground mobile robots can only partially deform during wheel-leg switching, resulting in failure to achieve better environmental adaptability. Metamorphic mechanisms can be introduced into car structure designs. A new type of wheel-legged ground mobile robot, namely a deformable robot, is proposed in this study. Compared with traditional wheel-legged ground mobile robots, the deformable robot is capable of global reconfiguration, that is, when transitioning between the wheeled type (vehicle state) and the legged type (humanoid state), the shape, structure, degrees of freedom, and position of the centre of mass will change significantly. First, based on the characteristics of the wheel-legged compound motion, a structural model of the deformable robot was proposed and designed, and its reconfiguration motion was planned. Then, a kinematic model of the coupled reconfiguration process of the deformable robot was established. A horizontal lifting model was created to keep the front body level when lifting. The motion law of each active joint angle over time was designed based on the requirements of the reconfiguration motion smoothness. The criterion of reconfiguration stability was established and measures to improve it were proposed. Finally, based on the simulation verification of the smoothness, horizontality, and stability of the coupled reconfiguration of the system, a prototype of the deformable robot was developed, and a coupled reconfiguration experiment was conducted on an actual road surface. The experiment results show that the reconfiguration motion of the deformable robot between the vehicle state and the humanoid state had good motion qualities

    CVLight: Decentralized Learning for Adaptive Traffic Signal Control with Connected Vehicles

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    This paper develops a decentralized reinforcement learning (RL) scheme for multi-intersection adaptive traffic signal control (TSC), called "CVLight", that leverages data collected from connected vehicles (CVs). The state and reward design facilitates coordination among agents and considers travel delays collected by CVs. A novel algorithm, Asymmetric Advantage Actor-critic (Asym-A2C), is proposed where both CV and non-CV information is used to train the critic network, while only CV information is used to execute optimal signal timing. Comprehensive experiments show the superiority of CVLight over state-of-the-art algorithms under a 2-by-2 synthetic road network with various traffic demand patterns and penetration rates. The learned policy is then visualized to further demonstrate the advantage of Asym-A2C. A pre-train technique is applied to improve the scalability of CVLight, which significantly shortens the training time and shows the advantage in performance under a 5-by-5 road network. A case study is performed on a 2-by-2 road network located in State College, Pennsylvania, USA, to further demonstrate the effectiveness of the proposed algorithm under real-world scenarios. Compared to other baseline models, the trained CVLight agent can efficiently control multiple intersections solely based on CV data and achieve the best performance, especially under low CV penetration rates.Comment: 29 pages, 14 figure

    Recurrent Cellulitis Associated with Long-Term Intrathecal Opioid Infusion Therapy: A Case Report and Review of the Literature

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    Lower-limb edema is recognized as an untoward side effect of intrathecal opioid therapy. Cellulitis, an acute, spreading pyogenic inflammation of the dermis and subcutaneous tissue, predisposed by persistent leg edema, can become problematic in patients on intraspinal opioid infusion therapy.To present a case of recurrent cellulitis in an elderly lady with persistent leg edema associated with intrathecal morphine/hydromorphone infusion therapy.Sixty-one-year-old woman with intractable chronic low back pain and bilateral leg pain treated with an intrathecal infusion of morphine up to 5 mg/day over 3 months with satisfactory pain control developed progressive lower extremity edema, complicated by recurrent cellulitis, requiring repeated hospitalization and intravenous antibiotic treatment. Switching to intrathecal hydromorphone helped minimally. Intrathecal baclofen and clonidine infusion resulted in complete resolution of leg edema and pain relief over the following 12 months.Intrathecal Baclofen and Clonidine may be used as alternatives to provide spinally mediated antinociception when intraspinal opioid fails due to pharmacological side effects such as persistent edema.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79174/1/j.1526-4637.2010.00854.x.pd

    Spectral reflectance reconstruction based on wideband multi-illuminant imaging and a modified particle swarm optimization algorithm

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    A method for spectral reflectance factor reconstruction based on wideband multiilluminant imaging was proposed, using a programmable LED lighting system and modified Bare Bones Particle Swarm Optimization algorithms. From a set of 16 LEDs with different spectral power distributions, nine light sources with correlated color temperatures in the range of 1924 K - 15746 K, most of them daylight simulators, were generated. Samples from three color charts (X-Rite ColorChecker Digital SG, SCOCIE ScoColor paint chart, and SCOCIE ScoColor textile chart), were captured by a color industrial camera under the nine light sources, and used in sequence as training and/or testing colors. The spectral reconstruction models achieved under multi-illuminant imaging were trained and tested using the canonical Bare Bones Particle Swarm Optimization and its proposed modifications, along with six additional and commonly used algorithms. The impacts of different illuminants, illuminant combinations, algorithms, and training colors on reconstruction accuracy were studied comprehensively. The results indicated that training colors covering larger regions of color space give more accurate reconstructions of spectral reflectance factors, and combinations of two illuminants with a large difference of correlated color temperature achieve more than twice the accuracy of that under a single illuminant. Specifically, the average reconstruction error by the method proposed in this paper for patches from two color charts under A+ D90 light sources was 0.94 and 1.08 CIEDE2000 color difference units. The results of the experiment also confirmed that some reconstruction algorithms are unsuitable for predicting spectral reflectance factors from multi-illuminant images due to the complexity of optimization problems and insufficient accuracy. The proposed reconstruction method has many advantages, such as being simple in operation, with no requirement of prior knowledge, and easy to implement in non-contact color measurement and color reproduction devices.Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (PID2022-138031NB-I00/SRA/ 10.13039/501100011033)National Natural Science Foundation of China (61671329, 61775170

    Influences of different developmental periods of taurine supplements on synaptic plasticity in hippocampal CA1 area of rats following prenatal and perinatal lead exposure

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    <p>Abstract</p> <p>Background</p> <p>Previous study has demonstrated that dietary taurine supplement protected rats from impairments of synaptic plasticity induced by postnatal lead exposure. However, little is known about the role of taurine in the presence of prenatal and perinatal lead exposure. We investigated the possible effect of taurine supplement on prenatal and perinatal lead-induced synaptic plasticity deficit and determined developmental periods critical for the effect of taurine.</p> <p>Results</p> <p>In the present study, taurine was administrated to prenatal and perinatal lead-exposed rats in different developmental periods: from prenatal to weaning (Lead+PW-Tau), from weaning to life (Lead+WL-Tau), and from prenatal to life (Lead+PL-Tau). We examined the input-output (I/O) function, paired-pulse facilitation (PPF) and the long-term potentiation (LTP) of field excitatory postsynaptic potential (fEPSP) in the hippocampal CA1 area of rats on postnatal days 18–25 (P18–25) or days 60–75 (P60–75). We found that (1) on P18–25, taurine had no evident effect on I/O functions and PPF ratios of lead-exposed rats but caused a 12.0% increase in the LTP amplitudes of these animals; (2) on P60–75, taurine significantly elevated lead depressed I/O functions and PPF ratios in Lead+PW-Tau and Lead+PL-Tau rats, but failed in Lead+WL-Tau rats. The amplitudes of LTP of lead-exposed rats were all significantly increased by additional taurine supplement in any developmental period compared with untreated rats. Thus, taurine appeared to have the most effect during the prenatal and lactation periods and its effects on younger rats would not be manifest until the adult life; and (3) the level of lead deposition in hippocampus was evidently reduced by additional treatment of taurine in lead-exposed rats, compared with untreated rats.</p> <p>Conclusion</p> <p>Taurine supplement can protect the adult rats from synaptic plasticity deficits following prenatal and perinatal lead exposure, and the protective effects are critical for the prenatal and lactation periods of lead-exposed rats.</p

    TikTalk: A Video-Based Dialogue Dataset for Multi-Modal Chitchat in Real World

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    To facilitate the research on intelligent and human-like chatbots with multi-modal context, we introduce a new video-based multi-modal dialogue dataset, called TikTalk. We collect 38K videos from a popular video-sharing platform, along with 367K conversations posted by users beneath them. Users engage in spontaneous conversations based on their multi-modal experiences from watching videos, which helps recreate real-world chitchat context. Compared to previous multi-modal dialogue datasets, the richer context types in TikTalk lead to more diverse conversations, but also increase the difficulty in capturing human interests from intricate multi-modal information to generate personalized responses. Moreover, external knowledge is more frequently evoked in our dataset. These facts reveal new challenges for multi-modal dialogue models. We quantitatively demonstrate the characteristics of TikTalk, propose a video-based multi-modal chitchat task, and evaluate several dialogue baselines. Experimental results indicate that the models incorporating large language models (LLM) can generate more diverse responses, while the model utilizing knowledge graphs to introduce external knowledge performs the best overall. Furthermore, no existing model can solve all the above challenges well. There is still a large room for future improvements, even for LLM with visual extensions. Our dataset is available at \url{https://ruc-aimind.github.io/projects/TikTalk/}.Comment: Accepted to ACM Multimedia 202

    Application effect of home-based rehabilitation program led by self-efficacy theory after temporomandibular joint disk repositioning

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    Objective·To explore the effects of home-based rehabilitation program led by self-efficacy theory after temporomandibular joint disk repositioning.Methods·Convenient sampling method was used. Patients with temporomandibular joint disk displacement who received temporomandibular joint disk repositioning in Shanghai Ninth People′s Hospital, Shanghai Jiao Tong University School of Medicine from August 2020 to January 2021 were selected as the control group, and patients admitted from February 2021 to July 2021 were selected as the intervention group. The control group received the conventional home-based rehabilitation care, while the intervention group were given home-based rehabilitation program led by self-efficacy theory. The general information questionnaire was used to collect the general information about patients. The joint range of motion measuring, rehabilitation exercise compliance questionnaire, General Self-efficacy Scale (GSES), and Mishel's Uncertainty in Illness Scale (MUIS) were used to investigate the joint range of motion, the rehabilitation exercise compliance score, the self-efficacy score and the uncertainty in illness score in the two groups at baseline and at 1, 3 and 6 months after surgery.Results·A total of 167 patients with temporomandibular joint disk displacement who received temporomandibular joint disk repositioning surgery were enrolled, including 96 cases in the control group and 71 cases in the intervention group. There was no difference in the general information between the two groups (P>0.05). There were no differences in the maximal mouth opening, maximum rightward lateral movement, maximum leftward lateral movement, self-efficacy score and uncertainty in illness score between the two groups at baseline (all P>0.05). The maximal forward extension in the intervention group was significantly less than that in the control group (P=0.008). Repeated measurement variance analysis showed that the self-efficacy scores in the intervention group were higher than those in the control group at 1, 3 and 6 months after surgery, and the differences were statistically significant (P=0.006, P=0.003, P=0.016). At 1 and 3 months after surgery, the scores of complexity dimension of uncertainty in illness in the intervention group were significantly lower than those in the control group (P=0.003, P=0.000). At 1 and 6 months after surgery, the rehabilitation exercise compliance scores in the intervention group were significantly higher than those in the control group (P=0.000, P=0.016). At 6 months after surgery, the maximum forward extension and maximum rightward lateral movement were significantly greater than those in the control group (P=0.024, P=0.008).Conclusion·The home-based rehabilitation program led by self-efficacy theory has a positive effect on improving the self-efficacy and compliance of rehabilitation exercise, reducing the disease uncertainty, and promoting the joint function recovery in patients receiving temporomandibular joint disk repositioning

    Hierarchical information clustering by means of topologically embedded graphs

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    We introduce a graph-theoretic approach to extract clusters and hierarchies in complex data-sets in an unsupervised and deterministic manner, without the use of any prior information. This is achieved by building topologically embedded networks containing the subset of most significant links and analyzing the network structure. For a planar embedding, this method provides both the intra-cluster hierarchy, which describes the way clusters are composed, and the inter-cluster hierarchy which describes how clusters gather together. We discuss performance, robustness and reliability of this method by first investigating several artificial data-sets, finding that it can outperform significantly other established approaches. Then we show that our method can successfully differentiate meaningful clusters and hierarchies in a variety of real data-sets. In particular, we find that the application to gene expression patterns of lymphoma samples uncovers biologically significant groups of genes which play key-roles in diagnosis, prognosis and treatment of some of the most relevant human lymphoid malignancies.Comment: 33 Pages, 18 Figures, 5 Table
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