• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1002-1009
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• 2007

A rapid, convenient homogeneous competitive enzyme immunoassay for estimating the amount of fenthion is described. The assay utilizes glucose-6-phosphate dehydrogenase-hapten conjugates that are inhibited in solution by antibodies obtained from bovine serum albumin-hapten conjugates. In order to investigate the effects of bridging group recognition on the sensitivity of dose response characteristics, the bridging groups of varying alkyl chain length were attached at the phosphate position of fenthion. Among the antibodies used, the one obtained from the use of hapten (fenthion analog) with the same bridging group structure that was used in preparing the enzyme-fenthion conjugates showed maximum inhibition (up to 51.8%) in the absence of fenthion. In the presence of fenthion, the activity of the enzyme-hapten conjugate is regained in an amount proportional to the fenthion concentration. Under the optimized condition, the $ED_{50}$ value for fenthion was $0.809{\mu}g/ml$. The assay developed in this study is a rapid effective screening method for fenthion prior to precise analysis.

• Journal of The Korean Association For Science Education
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• v.28 no.1
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• pp.75-88
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• 2008

The purpose of this study was to understand the factors affecting interactions as well as the students' learning process in small group activities. For this purpose, the changes and characteristics of students' interactions in scientific inquiry experiments were analyzed. This study focused on 2 homogeneous small groups of eighth graders. Students were involved in 13 inquiry experiments for one year and students' interactions in each experiments were observed and recorded using video/audio and the data recorded were transcribed. The analysis of data was based on the method of making a note by looking on and listening to the data repeatedly. Changes in the interactions of the two homogeneous groups differ remarkably. In small group A, owing to the conflicts of students' emotions, learning through social interactions became to be impossible. On the other hand, the interactions in small group B became more active. It seems that this changes are affected largely by the existence of peers who are able to mediate different opinions or feelings among group members. In general, middle school students were poor at receiving peers' opinion, cared a lot about writing reports. The less able students tended to be placed at a disadvantageous position in experiment lessons emphasizing social interactions. Four factors that affected the change of interactions were identified: Is the aim of experiments the understanding or completion of report? Is there any attitude towards peers' suggestions? Is there a disposition to care about peers? Is there any peer to mediate on peers' opinions or feelings? Educational implications of the progression of activities emphasizing interactions and the organization of grouping were drawn.

• Journal of the Korean Mathematical Society
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• v.34 no.1
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• pp.23-42
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• 1997

A 6-dimensional sphere considered as a homogeneous space $G_2/SU(3)$ where $G_2$ is the group of automorphism of the octonians O. From this representation, we can define an almost comlex structure on a 6-dimensional sphere by making use of the vector cross product of the octonians. Also it is known that a homogeneous space $G_2/U(2)$ coincides with the Grassmann manifold of oriented 2-planes of a 7-dimensional Euclidean space.

• Journal of the Korean Mathematical Society
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• v.42 no.3
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• pp.499-516
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• 2005

We obtain the type set for the fractional integral operator along the curve $(t,t^2,\;{\alpha}t^3)$ on the three dimensional Heisenberg group when $\alpha\neq{\pm}1/6$. The proof is based on the Fourier inversion formula and the angular Littlewood-Paley decompositions in the Heisenberg group in [5].

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.117-129
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• 2000

This paper discusses the lateral behavior of group pile in homogeneous and non- homogeneous (two layered) soil. In the group pile, the model tests were to investigate the effects on spacing-to-diameter ratio of pile, pile array, ratio of pile spacing, constraint condition of pile tip, eccentric load and ground condition. The group efficiency and lateral deflection induced in active piles were found to be highly dependent on the spacing-to-diameter ratio of pile, number of pile. Lateral bearing capacities in the group piles of fixed tip, in the case of 6D spacing and $3\times3$ array, were 40-100% higher than those in the group pile of free tip. Based on the results obtained, a spacing-to-diameter of 6.0 seems to be large enough to eliminate the group effect for the case of relative density of 61.8% and 32.8%, and then each pile in such a case behaves essentially the same as a single pile. However, in the case of dense sand, it can be estimated that a spacing-to-diameter of 8.0 seems to be large enough to eliminate the group effect. In this study the group efficiency is illustrated in experimental function with spacing-to-diameter, S/D, relative density and number of pile. The distribution of shear force in lead row piles, in the case of 3$\times$3 array group pile, was 41.6-52.4% for 3D spacing and 34-40% for 6D spacing, respectively. The shadowing effect for the parallel direction of lateral loading appears to be more significant than the one for the perpendicular direction of lateral loading.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.1
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• pp.13-26
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• 2024

Objectives: The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. Materials and Methods: We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). Results: In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Conclusion: Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

• Communications of the Korean Mathematical Society
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• v.37 no.2
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• pp.371-384
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• 2022

Fix an integer n ≥ 1. Then the simplex Π_n, Birkhoff polytope Ω_n, and Latin square polytope Λ_n each yield projective geometries obtained by identifying antipodal points on a sphere bounding a ball centered at the barycenter of the polytope. We investigate conditions for homogeneous coordinates of points in the projective geometries to locate exact vertices of the respective polytopes, namely crisp distributions, permutation matrices, and quasigroups or Latin squares respectively. In the latter case, the homogeneous conditions form a crucial part of a recent projective-geometrical approach to the study of orthogonality of Latin squares. Coordinates based on the barycenter of Ω_n are also suited to the analysis of generalized doubly stochastic matrices, observing that orthogonal matrices of this type form a subgroup of the orthogonal group.

• Journal of Science Education
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• v.41 no.2
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• pp.195-212
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• 2017

Small group learning is an educational approach to allow students to solve the problems and to achieve a common goal. Especially, small group learning in science education is one of the most important educational approaches and effective to ensure understanding of a topic. Small group learning consisting of three students in science education maximize student understanding and learning efficiency. However, It is reported that the effects of small group learning on achievement show different results, corresponding to different grouping methods(homogeneous/heterogeneous). This study investigated the effects of grouping method on difference of ecological niche of photosynthesis concepts. To achieve this, 1107 7th students were composed of homogeneous and heterogeneous groups classified into top, middle, and bottom levels. The photosynthesis units were divided into four categories: the photosynthesizing place, the substances of photosynthesis, required materials for the photosynthesizing, and environmental factors affecting photosynthesis. A questionnaire was composed by selecting concepts having a frequency of 4% or more based on prior studies on the change of the ecological status of photosynthesis. The questionnaire was scored in terms of relativity and understanding on each of the proposed concepts in the four categories. The result of this study is as set forth below. 1) There was an enhancement of learning the concept of science in small group classes consisting of 3 students. 2) To enhance the average upon composing of a group, it is proposed that the group should be formed homogeneously, and to reduce the deviation between the members, it is proposed that the group should be formed heterogeneously. Through this study, it is expected that specific studies verifying the difference or effect on the duplicity of results are conducted based on the composition of groups.

• Journal of The Korean Association For Science Education
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• v.32 no.10
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• pp.1551-1566
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• 2012

In this study, the effects of grouping by students' collectivism in cooperative learning strategy applied to middle school science classes on their academic achievement, science learning motivation, and perceptions of science learning environment were investigated. Students' perceptions of cooperative learning were also studied through survey and interview. The students were assigned to the control, heterogeneous, and homogeneous groups, and taught for 12 class hours. The analyses of results revealed that interactive effects between the instruction and the level of collectivism were found in the test scores of achievement, science learning motivation, and relevance, and that there were main effects in the test scores of confidence, perceptions of science learning environment, affiliation, and rule clarity. The achievement test scores of the students with low collectivism in the homogeneous group were significantly higher than those in the heterogeneous group. The test scores on science learning motivation and relevance of the students with high collectivism in the homogeneous and heterogeneous groups were significantly higher than those in the control group. In addition, the test scores of confidence and affiliation in the treatment groups were significantly higher than those in the control group. The test scores on perceptions of science learning environment and rule clarity in the homogeneous groups were significantly higher than those in the control group. There were also differences in the perceptions of science cooperative learning by students' collectivism.

• Journal of The Korean Association For Science Education
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• v.24 no.6
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• pp.1063-1069
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• 2004

This study investigated the effects of grouping method in solving chemistry problems using Think-Aloud Paired Problem Solving (TAPPS). Three classes (125 students) of a co-ed high school in Seoul were randomly assigned to the control, the homogeneous TAPPS, and the heterogeneous TAPPS groups. Prior to the instructions, a test of awareness of metacognition was administered. In the treatment groups, students were grouped into either homogeneous or heterogeneous group on the basis of their pre-achievement levels, and worked in pairs on chemistry problems about chemical equation and stoichiometry. Students' analytical skill, problem solving ability, and awareness of metacognition were examined after the instructions. One-way ANCOVA results indicated that the scores of the homogeneous TAPPS group in the analytical skill test were significantly higher than those of the heterogeneous TAPPS group. However, there were no significant differences among the three groups in the problem solving ability and the awareness of metacognition.