4,179 research outputs found

    Constructing minimal telescopers for rational functions in three discrete variables

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    We present a new algorithm for constructing minimal telescopers for rational functions in three discrete variables. This is the first discrete reduction-based algorithm that goes beyond the bivariate case. The termination of the algorithm is guaranteed by a known existence criterion of telescopers. Our approach has the important feature that it avoids the potentially costly computation of certificates. Computational experiments are also provided so as to illustrate the efficiency of our approach

    An Analysis of Information Systems Research in Chinese Mainland

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    This study examines information systems (IS) research in Chinese Mainland in recent years and identifies the similarities and the differences between international and Chinese IS research in terms of research topics and research methods. The data consists of a total of 410 research papers published in ten leading Chinese academic journals related to IS over the five-year period from 1999 to 2004. Compared to IS research abroad, the following may be said of Chinese IS research: (1) Systems-related issues, especially system design issues, system implementation, analytical models and tools, DSS/ESS/EIS are emphasized in research topics, whereas human-related and research methodologies issues are scarce. (2) Empirical studies, including case study, survey and experiment, are few and far between. (3) The majority of non-empirical studies focus on applications and conceptual description of IS, mainly in different applied fields and introducing or illustrating hot topics abroad. The general shift from traditional issues such as system design to non-technical problems is still continuing. There is a need to go beyond mere description of IS related phenomenon and to move away from non-empirical to empirical studies

    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

    THE PREDICTION OF FATIGUE-RELATED MUSCLE ADAPTATION IN DIFFERENT WORKLOAD DURING CYCLING ROWING EXERCISE

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    The purpose of this study was to identify the fatigue-related muscles during the different percentage of the maximal workload. Seven subjects were recruited and, firstly, performed the maximal workload test for 3 minutes. After 24 hours, the different workload tests (60%, 70% and 80% of the maximal workload) were used to reveal the fatigue-related muscle. The result showed that the biceps and triceps had the extreme contribution at the minor and greater workload. However, the neuromuscular fatigue threshold (NFT) is to predict the possibly fatigue muscle condition during the entire exercise. And the most contribution of the EMG expression didn’t stand for the greater value of the EMG number

    Adaptive gradient-based block compressive sensing with sparsity for noisy images

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    This paper develops a novel adaptive gradient-based block compressive sensing (AGbBCS_SP) methodology for noisy image compression and reconstruction. The AGbBCS_SP approach splits an image into blocks by maximizing their sparsity, and reconstructs images by solving a convex optimization problem. In block compressive sensing, the commonly used square block shapes cannot always produce the best results. The main contribution of our paper is to provide an adaptive method for block shape selection, improving noisy image reconstruction performance. The proposed algorithm can adaptively achieve better results by using the sparsity of pixels to adaptively select block shape. Experimental results with different image sets demonstrate that our AGbBCS_SP method is able to achieve better performance, in terms of peak signal to noise ratio (PSNR) and computational cost, than several classical algorithms

    Antifungal effects of sisal leaf juice on Lasiodiplodia theobromae, the causal agent of mulberry root rot

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    This study was carried out to evaluate the antifungal activities of leaf juices (fresh juice, fermented juice, boiled juice and sterile juice) of nine sisal varieties on Lasiodiplodia theobromae, the causal agent of mulberry root rot. Results show that all the leaf juices could inhibit the mycelial growth in different degrees (the inhibitory rates ranged from 63.3 to 100%), due to different varieties and treatments. Among the nine varieties, the inhibition effects of hybrid 76416 and Agave americana were the best with absolute inhibition of all the leaf juice treatments against the mycelial growth, followed by Agave Amaniensis, Agave virdis, Agave angustifolia and Hybrid 11648. The inhibitory effect of some fresh juices would be cut down after being fermented, boiled and sterilized. The treated mycelia of L.theobromae were malformed, enlarged, broken and plasma leaked when observed under the microscope. Most of the leaf juices could inhibit the conidial germination absolutely, except A.amaniensis, H.11648 and A. angustifolia. The average germination rate of A. amaniensis, H.11648 and A. angustifolia was 72.4, 16.6 and 13%, respectively. The control efficiency of the fresh juice of H. 11648 against mulberry root rot in the field reached 73.1%.Key words: Sisal, leaf juice, anti-fungi, anti-fungal activities, mulberry root rot, Lasiodiplodia theobromae

    PXR-Mediated Upregulation of CYP3A Expression by Herb Compound Praeruptorin C from Peucedanum praeruptorum

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    We recently reported that Praeruptorin C effectively transactivated the mRNA, protein expression, and catalytic activity of CYP3A4 via the CAR-mediated pathway, but whether and how PC could affect the expression and catalytic activity of CYP3A4 via PXR pathway remains unknown. Therefore, in this study, the effect of PC on the CYP3A gene expression was investigated in mice primary hepatocytes after knockdown of PXR by transient transfection of PXR siRNA, and the gene expression, protein expression, and catalytic activity of CYP3A4 in the LS174T cells with PXR overexpression were determined by real-time PCR, western blot analysis, and LC-MS/MS-based CYP3A4 substrate assay, respectively. We found that the level of CYP3a11 gene expression in mouse primary hepatocytes was significantly increased by praeruptorin C, but such an induction was suppressed after knockdown of pregnane X receptor by its siRNA. In PXR-overexpressed LS174T cells, PC significantly enhanced CYP3A4 mRNA, protein expression, and functional activity through PXR-mediated pathway; conversely, no such increase was found in the untransfected cells. These findings suggest that PC can significantly upregulate CYP3A level via the PXR-mediated pathway, and this should be taken into consideration to predict any potential herb-drug interactions between PC, Qianhu, and the other coadministered drugs
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