• Journal of Plant Biology
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• v.36 no.4
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• pp.399-406
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• 1993

유채(Brassica napus L. cv. Topas) 소포자 배양에 의한 기내 배발생 과정을 관찰하고 발생과정에 따른 총단백질의 변화 양상을 이차원 전기영동을 통하여 분석하였다. 배양에 적합한 소포자의 발달 단계는 4,6-diamidino-2-phenylindole (DAPI) 형광염색으로 핵상관찰을 통하여 결정하였다. 최초의 소포자 생존율은 63.9%였으며 이러한 생존율의 차이로 배양초기에 소포자의 이형성이 나타났다. 배 발달 경로에 따른 최초의 세포분열은 화분벽 안에서 균등분열로 시작되어 배병의 발달이 선행된 후 배 발생이 일어났으며, 구형, 심장형, 어뢰형으로의 배 발달은 여러 조직의 분화와 더불어 빠르게 진행되었다. 소포자배 발달과정을 치상단계의 소포자, 배양 3일째의 초기 분열세포, 구형 및 심장형배, 어뢰형배, 성숙한 자엽단계의 배 등의 5단계로 나누어 각각 2차원 전기영동을 수행한 결과, 최초 소포자 단계에서 나타났던 23개의 단백질들은 배 달달 경로로 진행됨에 따라 사라지고, 배양 3일째에는 8개의 단백질이 특이적 또는 지속적으로 발현되었다. 배의 발달과 더불어 20∼50 kD 사이에서 총 42개의 단백질이 급격히 나타나거나 또는 후기 배로 진행하면서 점차적으로 발현되었다.

• Korean Journal of Childcare and Education
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• v.6 no.3
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• pp.153-174
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• 2010

The purpose of this research was to investigate the effects of servant leadership, teacher development stage and organizational effectiveness. Subjects in this study were 259 teachers working at kindergartens and child care centers in Seoul and the Capital area of Korea. Servant Leadership Questionnaire(Kim, 2004), Teacher Development Stage Questionnaire(Lee, 2007), Organizational Commitment Questionnaire(Kim, 1998), Job Satisfaction Questionnaire(Kim, 2007), Teacher Job Satisfaction Questionnaire(Noh, 2001), and Job Performance Questionnaire(Kim, 1983) were used. Descriptive statistics, T-tests, Pearson's correlation, and hierarchical regression analysis were performed. Results showed that servant leadership, teacher development stage and organizational effectiveness were highly correlated with one another. Variables of servant leadership and teacher development were significant predictors of organizational effectiveness. Conclusions suggest that organizational effectiveness was multiply determined.

• The Korean Journal of Malacology
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• v.31 no.1
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• pp.9-19
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• 2015

Germ cell development and cyclic changes in the epithelial cells of the seminal vesicle of the male rapa whelk, Rapana venosa, were investigated by cytological and histological observations. The process of germ cell development can be classified into five stages: (1) spermatogonial, (2) primary spermatocyte, (3) secodary spermatocyte, (4) spermatid, and (5) spermatozoon. In particular, four atypical cells (Type IA, IB, IIA and IIB cells) occur among normal germ cells in the acini during spermatogenesis. Presumably, the atypical cells, which have lysosome-like vacuoles or lysosome-like bodies in the cells, are involved in breakdown and absorption themselves in the acini. However, atypical cells were not found in the epithelial cells of the inner layer of the seminal vesicle. A considerable amount of spermatozoa are transported from the testis towards the the seminal vesicles until late July. The main coupulation period is between June and July. The process of the cyclical changes of the seminal vesicles can be classified into three phases: (1) resting, (2) accumulating, and (3) spent. Yellow granular bodies are involved in resorption or digestion of residual spermatozoa.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.420-428
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• 2015

The majority of cultivated varieties of grape have perfect flowers that are clustered in an individual inflorescence. Grape flower has a single pistil, five stamens, a protective flower cap (calyptra), and a calyx. After fertilization, an individual flower develops into a single berry. Although there are a number of reported studies focusing on berry formation, berry enlargement, and sugar accumulation in grape, the morphological studies of flower, including gametophyte morphogenesis and structural change in floral organs, have not yet been studied in detail. In this study, we investigated the flower structure and development characteristics of grape using microscopy and defined the floral development stages 9 to 13 based on microspore or male gametophyte development stage from tetrad to mature pollen. We used seeded diploid table grapes 'Campbell Early' (Vitis labruscana) and 'Tamnara' (V. spp.) as plant materials. At floral development stage 9, pollen mother cells develop to tetrads. During floral development stages 10 to 11, unicellular microspore develop to mid bicellular pollen. At the end of floral stage 12, male gametophyte develops to mature tricelluar pollen. In floral stage 13, the flower cap falls off and flower bud opens. During floral development stages 9 to 12, there were no major changes in calyx length, whereas the length of the flower cap continuously increased. The flower cap-to-calyx length ratio was 2.0, 3.0, 4.5, and 6.5 at floral stages 9, 10, 11, and 12, respectively. The flower cap-to-calyx length ratio was consistent in the two grape cultivars, suggesting that the ratio is a morphological character representing floral development stage. This study provides a reference for determining floral development stage of the two grape cultivars. It will be useful for the determination of optimum time for microspore culture needed to generate doubled haploid lines and appropriate gibberellic acid treatment needed to induce parthenocarpic fruit development in 'Tamnara' grape.

• Journal of Life Science
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• v.13 no.6
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• pp.822-828
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• 2003

This study was carried out to investigate the changes of enzymes and micro inorganic nutrients that is associated with flower senescence during flower development in tulip cultivars, ‘Apeldoorn’ and ‘Golden Apeldoorn’. Ribonuclease, peroxidase and protease activities were gradually increased from the stage of early flowering to later Polyphenol oxidase showed the highest activity at stage 5, which the flower was in full bloom indicating that it acts at an initial stage of flower senescence. The protease activity was different in the petal extracts during flower development between the cultivars ‘Apeldoorn’ (red petal) and ‘Golden Apeldoorn’ (yellow petal). This result suggested that protease might relate to pigment biosynthesis in petal of tulip. In contrast to the decrease of inorganic nutrients K, Mn, Zn and P contents during floral development, Ca, Mg and Fe showed the gradual increasement that is similar with ribonuclease, peroxidase and protease. It suggests that they have some interaction during flower senescence.

• Journal of The Korean Association For Science Education
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• v.8 no.1
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• pp.81-94
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• 1988

본 연구의 목적은 Piaget의 인지발달단계(전조작 구체적 조작 단계)에 따른 자연과 개념획득에 효과적인 교수전략을 탐색하기 위한 연구로서, 첫째는 문헌연구를 통해서, Piaget의 인지이론을 기초로한 교육론과 개념학습을 위한 교수전략을 연구함으로써 전조작 단계의 어린이, 구체적 조작단계의 어린이에게는 연역적 교수전략보다 귀납적 교수전략이 더 효과적이며, 구체적 조작단계의 어린이에게는 초보적인 논리능력이 발달하므로 연역적 교수전략도 가능하며, 이 2가지의 인지단계가 복합돼 있는 국민학교 2학년 집단에게는 귀납적 교수전략이 보다 효과적일 것이라는 데에 이르렀다. 둘째로는 현장 실험연구로서 실제로 자연과 2학년의 한 단원을 연억 귀납의 교수전략의 단계에 맞추어 적용하였다. Piaget의 인지 발달 단계예 따른 자연과 개념획득을 위한 효과적인 교수전략을 탐색해본 결과는 다음과 같다. 첫째, 전조작 단계의 아동은 자연과 개념획득을 위해서는 연역적 교수전략보다 귀납적 교수전략이 더 효과적이다. 둘째, 구체적 조작단계의 아동에게는자연과 개념획득을 위한 교수전략은 귀납적 교수전략이 효과적이지만, 연역적 교수전략도 가능하다는 것이다. 이로써 국민학교 2학년 즉, 전조작 단계와 구체척 조작단계가 복합돼있는 집단에게는 연역적 교수전략보다 귀납적 교수전략이 보다 더 효과적이라는 것이다.

• Journal of The Korean Association of Information Education
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• v.18 no.4
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• pp.559-566
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• 2014

This is to understand the neurological dynamic cognitive processes of math learning based on the abstract mappings( level A2), abstract systems(level A3), and single principles(level A4), which are principles of Fischer's cognitive development theory. Math learning requires flexibility to adapt existing brain function in selecting new neurophysiological activities to learn desired knowledge. This study suggests a general statistical framework for the identification of neurological patterns in different abstract learning change with optimal support. We expected that functional brain networks derived from a simple math learning would change dynamically during the supportive learning associated with different abstract levels. Task based patterns of the brain structure and function on representations of underlying connectivity suggests the possible prediction for the success of the supportive learning.

• Journal of the Korean Chemical Society
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• v.64 no.2
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• pp.111-118
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• 2020

The purpose of this study is to explore the progression of MMK and the relationship between MMK progression level and actual practice. First, the Rasch model was used to measure MMK progression level of 51 students twice during the interval of one year. Thereafter, chi-squared test was used to determine whether there was a significant change in MMK progression. As a result of chi-squared test, there was no statistically significant change in MMK progression (p>.05). Secondly, we analyzed the relationship between MMK progression level and practice for 7 gifted students. As a result of the analysis, it was confirmed that the student's response in practice can not exceed MMK progression level. There were also cases where students have high MMK progression level showed low response in practice. The results of these two studies show that gifted education programs are needed to increase MMK progression and to provide gifted education that can connect knowledge and practice.

• Development and Reproduction
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• v.13 no.1
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• pp.25-33
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• 2009

The cycle of the seminiferous epithelium and development of spermatids of Apodemus speciosus peninsulae were observed using a light microscope. On the basis of developing spermatocyte and spermatid, the cycle of the seminiferous epithelium was divided into 9 stages. Type Ad spermatogonia were appeared in all stages ($I{\sim}IX$). The Ap, In, and B types of spermatogonia were appeared from stage I, II and III, and IV, respectively. In prophase of first meiosis, the leptotene spermatocytes appeared from stage V and VI, zygotene spermatocytes from stages I, II, VII, VIII, and IX, pachytene spermatocytes from stage III to VII, diplotene spermatocytes in the stage VIII, and secondary spermatocytes in stage IX. On the basis of morphology of spermatid head, developing of nuclear and acrosome and the morphological change of cytoplasm, the developing of spermatids was divided into 12 steps. Considering all the results, A. s. peninsulae displayed very similar result with A. agrarius coreae that is allied species when compare correct characters developing of spermatids with spermatogonia and appearance time of the spermatocyte. Appearance time of the same cell and number of spermatogonial generation was thought that characters of the species, and information may be useful in identifying the species.

• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.719-743
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• 2013

Proportional reasoning is considered as a difficult concept to most elementary school students and might be connect to functional thinking, algebraic thinking, and mathematical thinking later. The purpose of this study is to analyze the sixth graders' development level of proportional reasoning so that children's problem solving processes on different proportional problem items were investigated in a way how the problem type of proportion and the degree of ill-structured affect to their levels. Results showed that the greater part of participants solved problems on the level of proportional reasoning and various development levels according to type of problem. In addition, they showed highly the level of transition and proportional reasoning on missing value problems rather than numerical comparison problems.