660 research outputs found

    Adult Civic Educators’ Educational Needs Assessment in the Context of South Korea

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    This study measured current and required levels of educational capacities of adult civic educators in South Korea. The pairwise comparisons provided implications for more urgent and important professional development areas

    Simple and convenient method for adipose-derived mesenchymal stem cells serum-free medium development

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    2-(1-Propyl-2,6-distyryl-1,4-dihydro­pyridin-4-yl­idene)malononitrile

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    In the title compound, C27H23N3, the dihedral angles between the central pyridine ring and the two outer benzene rings are 32.6 (1) and 52.0 (1)°. The compound displays inter­molecular π–π inter­actions between adjacent six-membered rings, the shortest centroid–centroid distance being 3.981 (3) Å

    DFT Study on the Nucleophilic Addition Reaction of Water and Ammonia to the Thymine Radical Cation

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    The nucleophilic addition reactions of water and ammonia molecules toward the C5−C6 double bond of thymine radical cations were investigated using density functional theory. We predicted that the nucleophilic addition favored the C5-site of thymine radical cations, in contrast to the previous experimental observations in bulk solution where the addition product to the C6-site was dominant. Considering the molecular orbital factors, we estimated the relative reactivity of the C5- and C6-sites of thymine radical cations for the nucleophilic addition of ammonia. We found that the C5 was more reactive than the C6 for the small-size clusters of Thy_1(NH_3)_n+, n = 0−2, in the gas phase and even in aqueous solution, though the difference in the reactivity between the two sites became smaller as the number of ammonia molecules increased. This variation of the reactivity was attributed to the electron density redistribution within the thymine radical cations induced by the ammonia molecules as a nucleophile. We suggest that the dominance of the C6-addition product in bulk solution is mainly due to the higher stability of the C6-addition product by solvation, rather than to the higher reactivity of the C6-site for the nucleophilic addition

    Optimal Detection Range of RFID Tag for RFID-based Positioning System Using the k-NN Algorithm

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    Positioning technology to track a moving object is an important and essential component of ubiquitous computing environments and applications. An RFID-based positioning system using the k-nearest neighbor (k-NN) algorithm can determine the position of a moving reader from observed reference data. In this study, the optimal detection range of an RFID-based positioning system was determined on the principle that tag spacing can be derived from the detection range. It was assumed that reference tags without signal strength information are regularly distributed in 1-, 2- and 3-dimensional spaces. The optimal detection range was determined, through analytical and numerical approaches, to be 125% of the tag-spacing distance in 1-dimensional space. Through numerical approaches, the range was 134% in 2-dimensional space, 143% in 3-dimensional space

    In vitro embryo rescue for the production of hypotetraploids after cross between hypotetraploid and tetraploid grape cultivars

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    Consumer demand for seedless grape with high quality and large berry has been increasing. Breeding of hypotetraploid grape was suggested as one of promising methods to satisfy it, but low frequency of hypotetraploid occurrence and low seed germination by abortive embryo were indicated as the major problem to hamper the development of hypotetraploid grape. Hence, this study was carried out to evaluate the basic efficiency of in ovulo embryo culture after the cross between hypotetraploid (‘Hanareum’) and tetraploid (‘Honey Black’ and ‘Kyoho’) grape cultivars on the establishment of hypotetraploid grapes. Embryos and plantlets were hardly obtained in ovules cultured at six after the cross pollination (WAP), but ovules inoculated at 10 WAP produced more embryos as well as plantlets regardless of cross combination. Furthermore, we found that embryo formation was not affected by the basal media in ovules cultured at six WAP, but utilization of specific medium can be more beneficial for embryo formation when ovules were cultured at 10 WAP. A total of 17 plants were obtained from ovules cultured at 10 WAP, and above 50% of plants were identified as hypotetraploid grapes. These results indicate that in vitro embryo rescue after cross pollination between hypotetraploid and tetraploid grape can enhance the efficiency for the breeding of hypotetraploid grapes

    Segmentation of Planar Surfaces from Laser Scanning Data Using the Magnitude of Normal Position Vector for Adaptive Neighborhoods

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    Diverse approaches to laser point segmentation have been proposed since the emergence of the laser scanning system. Most of these segmentation techniques, however, suffer from limitations such as sensitivity to the choice of seed points, lack of consideration of the spatial relationships among points, and inefficient performance. In an effort to overcome these drawbacks, this paper proposes a segmentation methodology that: (1) reduces the dimensions of the attribute space; (2) considers the attribute similarity and the proximity of the laser point simultaneously; and (3) works well with both airborne and terrestrial laser scanning data. A neighborhood definition based on the shape of the surface increases the homogeneity of the laser point attributes. The magnitude of the normal position vector is used as an attribute for reducing the dimension of the accumulator array. The experimental results demonstrate, through both qualitative and quantitative evaluations, the outcomes’ high level of reliability. The proposed segmentation algorithm provided 96.89% overall correctness, 95.84% completeness, a 0.25 m overall mean value of centroid difference, and less than 1° of angle difference. The performance of the proposed approach was also verified with a large dataset and compared with other approaches. Additionally, the evaluation of the sensitivity of the thresholds was carried out. In summary, this paper proposes a robust and efficient segmentation methodology for abstraction of an enormous number of laser points into plane information
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