1,608 research outputs found

    Explore the Functional Connectivity between Brain Regions during a Chemistry Working Memory Task.

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    Previous studies have rarely examined how temporal dynamic patterns, event-related coherence, and phase-locking are related to each other. This study assessed reaction-time-sorted spectral perturbation and event-related spectral perturbation in order to examine the temporal dynamic patterns in the frontal midline (F), central parietal (CP), and occipital (O) regions during a chemistry working memory task at theta, alpha, and beta frequencies. Furthermore, the functional connectivity between F-CP, CP-O, and F-O were assessed by component event-related coherence (ERCoh) and component phase-locking (PL) at different frequency bands. In addition, this study examined whether the temporal dynamic patterns are consistent with the functional connectivity patterns across different frequencies and time courses. Component ERCoh/PL measured the interactions between different independent components decomposed from the scalp EEG, mixtures of time courses of activities arising from different brain, and artifactual sources. The results indicate that the O and CP regions' temporal dynamic patterns are similar to each other. Furthermore, pronounced component ERCoh/PL patterns were found to exist between the O and CP regions across each stimulus and probe presentation, in both theta and alpha frequencies. The consistent theta component ERCoh/PL between the F and O regions was found at the first stimulus and after probe presentation. These findings demonstrate that temporal dynamic patterns at different regions are in accordance with the functional connectivity patterns. Such coordinated and robust EEG temporal dynamics and component ERCoh/PL patterns suggest that these brain regions' neurons work together both to induce similar event-related spectral perturbation and to synchronize or desynchronize simultaneously in order to swiftly accomplish a particular goal. The possible mechanisms for such distinct component phase-locking and coherence patterns were also further discussed

    SAGITTAL AND FRONTAL LOWER LIMBS KINETICS DURING STEPPING DOWN IN TAICHI ELDERLY

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    The aim was to compare the kinetic characteristics of the beginning stance phase during stepping down in Taichi and normal elderly. Nine elderly taichi subjects and eleven matched controls participated in the study. Whole body kinematics and ground reaction forces (GRF) were recorded using 10 Vicon cameras (250Hz) and two Kistler force plates (1000Hz). Sagittal and frontal kinetic parameters were calculated by using Visual3D software. Differences in variables between groups were tested using t-test. The results indicated hip extensor / knee flexor / ankle plantarflexor / support moment and peak hip/knee/ankle power were greater in Taichi group. It was concluded that Taichi group has ability to translate forward movement (hip moment / power), to control body (knee moment /power) and to absorption energy (ankle moment / power) in sagittal plane

    The Enterprise Risk Management of Foreign Exchange Exposures: Evidence from Taiwanese Hospitality Industry

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    For this paper, I use the ARIMA model to study the relationship between business performance and exchange rate fluctuations. Through this model, the empirical results shows that the influences of foreign exchange rate fluctuations on the tourist hotel business performance are significant and different across currencies and firms. Furthermore, according to the framework of Kim (2013) we employ the modern portfolio theory proposed by Markowitz (1952) to give an optimal foreign exchange allocation for each tourist hotel company's financial decision-makers, which will avoid the risk of exchange rate fluctuations expose and reduce losses due to the fluctuations of exchange rates, and complete the construction of enterprise risk management system (ERM)

    Authenticity Preservation with Histogram-Based Reversible Data Hiding and Quadtree Concepts

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    With the widespread use of identification systems, establishing authenticity with sensors has become an important research issue. Among the schemes for making authenticity verification based on information security possible, reversible data hiding has attracted much attention during the past few years. With its characteristics of reversibility, the scheme is required to fulfill the goals from two aspects. On the one hand, at the encoder, the secret information needs to be embedded into the original image by some algorithms, such that the output image will resemble the input one as much as possible. On the other hand, at the decoder, both the secret information and the original image must be correctly extracted and recovered, and they should be identical to their embedding counterparts. Under the requirement of reversibility, for evaluating the performance of the data hiding algorithm, the output image quality, named imperceptibility, and the number of bits for embedding, called capacity, are the two key factors to access the effectiveness of the algorithm. Besides, the size of side information for making decoding possible should also be evaluated. Here we consider using the characteristics of original images for developing our method with better performance. In this paper, we propose an algorithm that has the ability to provide more capacity than conventional algorithms, with similar output image quality after embedding, and comparable side information produced. Simulation results demonstrate the applicability and better performance of our algorithm

    A LITERATURE REVIEW OF SUSTAINABLE TOURISM (1990-2016): DEVELOPMENT TRAJECTORY AND FRAMEWORK

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    Purpose of the study—Tourism is one of the largest and fastest growing industries in the world. Just like an enterprise today, sustainability is the long-term objective pursued by tourism industry. However, little effort has been made to systematically provide sufficient information to academicians and practitioners who have great research interests in sustainable tourism. Therefore, this paper aims to figure out the knowledge mapping of sustainable tourism and to indicate its research hot spots and trends for future research. Methodology—This paper surveys the development trajectory of sustainable tourism using a literature review and classification of articles retrieved from 5 online databases with solo keyword “sustainable tourism” from 1900 to 2016. Main findings—Based on the scope of 641 articles, this study reveals that the number of publication on sustainable tourism has significantly increased since 2006. In addition, these articles are scattered across 125 journals and mostly published in 23 academic journals. The majority of targeted countries/regions for sustainable tourism focus on Asia, Europe and America. Limitation—Restricted to limited knowledge, we make a brief literature survey on sustainable tourism from 1990-2016 to explore how sustainable tourism and its applications have developed in this period. Originality/value—In fact, sustainable tourism is a belief and an overall concept in every tourism activities. Though this research has done lots, it still has rooms to make more complete. Finally, we present a conceptual framework integrating 13 classifications criteria derived from our analysis with 3247 keywords. Most interestingly, we further present a conceptual framework with a visual effect to operationalize the coverage of sustainable tourism. Based on our analysis, any researcher can easily find the popular and right journal to get into it, if he/she is in need, he/she also can roughly know its applications so far and completely get a whole picture of sustainable tourism quickly

    Lowly Expressed Ribosomal Protein S19 in the Feces of Patients with Colorectal Cancer

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    Colorectal cancer (CRC) has become one of the most common fatal cancers. CRC tumorigenesis is a complex process involving multiple genetic changes to several sequential mutations or molecular alterations. P53 is one of the most significant genes; its mutations account for more than half of all CRC. Therefore, understanding the cellular genes that are directly or indirectly related to p53 is particularly crucial for investigating CRC tumorigenesis. In this study, a p53-related ribosomal protein, ribosomal protein S19 (RPS19), obtained from the feces of CRC patients is evaluated by using specifically quantitative real-time PCR and knocked down in the colonic cell line by gene silencing. This study found that CRC patients with higher expressions of RPS19 in their feces had a better prognosis and consistent expressions of RPS19 and BAX in their colonic cells. In conclusion, the potential mechanism of RPS19 in CRC possibly involves cellular apoptosis through the BAX/p53 pathway, and the levels of fecal RPS19 may function as a prognostic predictor for CRC patients

    An Improvement of the Triangular Inequality Elimination Algorithm for Vector Quantization

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    Abstract: This study proposes an improvement of the triangular inequality elimination (TIE) algorithm for vector quantization (VQ). More than 26% additional computation saving is achieved. The proposed approach uses dynamic and intersection (DI) rules to recursively compensate and enhance the TIE algorithm. The dynamic rule changes the reference codeword dynamically and reaches the smallest candidate group. The intersection rule removes redundant codewords from these candidate groups. The DI-TIE approach avoids the over-reliance on continuity of input signal. The VQ-based line spectral pair (LSP) quantization in ITU-T G.729 standard and some standard test images are used to test the contribution of the DI-TIE. Experimental results confirm that the DI rules in the TIE algorithm have an excellent performance. Moreover, in comparison with the quasi-binary search (QBS) approach, both the QBS and the DI-TIE methods are independent on the continuity of input signal. Nevertheless, the DI-TIE approach proposed in the paper is superior to the QBS method in the computation saving issue
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