12,744 research outputs found

    Nonlocal Flow of Convex Plane Curves and Isoperimetric Inequalities

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    In the first part of the paper we survey some nonlocal flows of convex plane curves ever studied so far and discuss properties of the flows related to enclosed area and length, especially the isoperimetric ratio and the isoperimetric difference. We also study a new nonlocal flow of convex plane curves and discuss its evolution behavior. In the second part of the paper we discuss necessary and sufficient conditions (in terms of the (mixed) isoperimetric ratio or (mixed) isoperimetric difference) for two convex closed curves to be homothetic or parallel.Comment: 23 page

    A combined analysis of PandaX, LUX, and XENON1T experiments within the framework of dark matter effective theory

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    Weakly interacting massive particles are a widely well-probed dark matter candidate by the dark matter direct detection experiments. Theoretically, there are a large number of ultraviolet completed models that consist of a weakly interacting massive particle dark matter. The variety of models makes the comparison with the direct detection data complicated and often non-trivial. To overcome this, in the non-relativistic limit, the effective theory was developed in the literature which works very well to significantly reduce the complexity of dark matter-nucleon interactions and to better study the nuclear response functions. In the effective theory framework for a spin-1/2 dark matter, we combine three independent likelihood functions from the latest PandaX, LUX, and XENON1T data, and give a joint limit on each effective coupling. The astrophysical uncertainties of the dark matter distribution are also included in the likelihood. We further discuss the isospin violating cases of the interactions. Finally, for both dimension-five and dimension-six effective theories above the electroweak scale, we give updated limits of the new physics mass scales.Comment: 33 pages, 11 figures, PandaX run10 data included and version accepted in JHEP, "code is available at the LikeDM website, https://likedm.hepforge.org/

    Tracing and Predicting Collaboration for Junior Scholars

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    Academic publication is a key indicator for measuring scholars' scientific productivity and has a crucial impact on their future career. Previous work has identified the positive association between the number of collaborators and academic productivity, which motivates the problem of tracing and predicting potential collaborators for junior scholars. Nevertheless, the insufficient publication record makes current approaches less effective for junior scholars. In this paper, we present an exploratory study of predicting junior scholars' future co-authorship in three different network density. By combining features based on affiliation, geographic and content information, the proposed model significantly outperforms the baseline methods by 12% in terms of sensitivity. Furthermore, the experiment result shows the association between network density and feature selection strategy. Our study sheds light on the re-evaluation of existing approaches to connect scholars in the emerging worldwide Web of Scholars

    The Study on Secure RFID Authentication and Access Control

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    Realizing Semantic Virtual Environments with Ontology and Pluggable Procedures

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    Multi-User Virtual Environment (MUVE) has attracted much attention recently due to the increasing number of users and potential applications. Fig. 1 shows the common components that a MUVE system may provide. Generally speaking, a MUVE refers to a virtual world that allows multiple users to log in concurrently and interact with each othe

    Designing Visible Light-Cured Thiol-Acrylate Hydrogels for Studying the HIPPO Pathway Activation in Hepatocellular Carcinoma Cells

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    Various polymerization mechanisms have been developed to prepare peptide-immobilized poly(ethylene glycol) (PEG) hydrogels, a class of biomaterials suitable for studying cell biology in vitro. Here, a visible light mediated thiol-acrylate photopolymerization scheme is reported to synthesize dually degradable PEG-peptide hydrogels with controllable crosslinking and degradability. The influence of immobilized monothiol pendant peptide is systematically evaluated on the crosslinking of these hydrogels. Further, methods are proposed to modulate hydrogel crosslinking, including adjusting concentration of comonomer or altering the design of multifunctional peptide crosslinker. Due to the formation of thioether ester bonds, these hydrogels are hydrolytically degradable. If the dithiol peptide linkers used are susceptible to protease cleavage, these thiol-acrylate hydrogels can be designed to undergo partial proteolysis. The differences between linear and multiarm PEG-acrylate (i.e., PEGDA vs PEG4A) are also evaluated. Finally, the use of the mixed-mode thiol-acrylate PEG4A-peptide hydrogels is explored for in situ encapsulation of hepatocellular carcinoma cells (Huh7). The effects of matrix stiffness and integrin binding motif (e.g., RGDS) on Huh7 cell growth and HIPPO pathway activation are studied using PEG4A-peptide hydrogels. This visible light poly-merized thiol-acrylate hydrogel system represents an alternative to existing light-cured hydrogel platforms and shall be useful in many biomedical applications

    THE EFFECT OF PASSIVE AND ACTIVE IMPULSE ON THE PERFORMANCES OF DROP JUMPS

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    This experiment is to investigate the ground reaction forces of lhree diHerent heights of drop-jumps (DJ) in order to understand the eHect of passive and active impulses on the performance of DJ. Eleven subjects were asked to perform DJs. AMIT force-platform and penny electrical gonia-meter were used to record the ground reaction forces and knee angular displacement. After treating the data and discussion, the conclusions were obtained. The active force as well as the active impulse are that of DJ20=DJ40=DJ60 whose result is consistent with the flight-height of these three diHerent DJ. On the other hand, the higher the jump-altitude is, the larger the passive impulse and passive force are. This result is very diHerent from that of flight-height, so the passive impulsive seems to have no help to prompt the performances of DJs. After further examination of the ground reaction force, we found that the key determinant process is the PARFD that slopes down as the jump-heights increase. The DJ60 induces the largest passive impulse but also accompanies negative PARFD. On other hand, the DJ20 induces the smallest passive impulse but accompanies positive PARFD. Finally, the performances of DJ20, DJ40 and DJ60 have no diHerence
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