• Title/Summary/Keyword: PCK

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A mathematics teacher's discursive competence on the basis of mathematical competencies (수학교과역량과 수학교사의 담론적 역량)

  • Choi, Sang-Ho;Kim, Dong-Joong
    • Communications of Mathematical Education
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    • v.33 no.3
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    • pp.377-394
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    • 2019
  • The purpose of this study is to scrutinize the characteristics of a teacher's discursive competence on the basis of mathematical competencies. For this purpose, we observed all semester-long classes of a middle school teacher, who changed her own teaching methods for the last 20 years, collected video clips on them, and analyzed classroom discourse. Data analysis shows that in problem solving competency, she helped students focus on mathematically important components for problem understanding, and in reasoning competency, there was a discursive competence which articulated thinking processes for understanding the needs of mathematical justification. And in creativity and confluence competency, there was a discursive competence which developed class discussions by sharing peers' problem solving methods and encouraging students to apply alternative problem solving methods, whereas in communication competency, there was a discursive competency which explored mathematical relationships through the need for multiple mathematical representations and discussions about their differences. These results can provide concrete directions to developing curricula for future teacher education by suggesting ideas about how to combine practices with PCK needed for mathematics teaching.

Core Curriculum Contents of Software Education for Preliminary Teacher based on Pedagogical Contents Knowledge (예비교사를 위한 교수내용지식 관점에서의 소프트웨어 교육내용 주요 내용 탐색)

  • Shin, Soo-bum;Han, Gyu-jung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.2
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    • pp.229-235
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    • 2019
  • The importance of pre-service teachers' curriculum that can run K12 school SW education is raised. However, there is insufficient study on the standard of SW curriculum for pre-service teachers in domestic. In this study, we analyzed domestic and foreign cases based on four kinds of contents knowledge. Domestic cases were found to be concentrated on curriculum contents of education and teaching methods. Through the analysis of cases in domestic and abroad, we presented the content of SW education based on knowledge of teaching contents for preliminary teachers. The main contents are all four areas, and the curriculum contents and the teaching method are emphasized the most, and the SW subject education experts are asked for the feasibility study. The results of the questionnaire survey showed that although the validity and consensus exceeded the standard, the CVR value for the student management field was lower than the standard value.

Aging Property Studies on Rubber Gasket for Polymer Electrolyte Membrane Fuel Cell Stack (고분자 전해질 연료전지 스택용 고무 개스킷의 노화특성 연구)

  • Kang, Dong-gug;Hur, Byung-ki;Lee, Dong-won;Seo, Kwan-ho
    • Applied Chemistry for Engineering
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    • v.22 no.2
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    • pp.149-154
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    • 2011
  • In order to explore properties of various rubber compounds after thermal aging under the condition similar to the operating environment of a fuel cell-stack, heat resistance and compression set of those compounds were investigated for a long term operation in $H_2SO_4$, $H_2O$, and LLC (ethylene glycol : $H_2O=50:50$) solution. It was assumed that aging Acrylonitrile butadiene rubber (NBR) and Elthylene Propylene diene rubber (EDPM) compound in the solution resulted in discoloration as time passed. It was also found that hydrolysis was developed on the Silicone rubber (VMQ) compound intentionally aged under acidic condition by means of TGA, SEM, and EDS analysis.

Effect of Resistance Training on Skeletal Muscle Gene Expression in Rats: a Beadarray Analysis (저항성 운동이 골격근 유전자 발현에 미치는 영향: Beadarray 분석)

  • Oh, Seung-Lyul;Oh, Sang-Duk
    • Journal of Life Science
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    • v.23 no.1
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    • pp.116-124
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    • 2013
  • The aim was to examine resistance exercise-related genes after 8 weeks of resistance training. Thirty-two male Sprague-Dawley rats were divided into four groups: 4 weeks sedentary (4 wks CON, n=8), 8 weeks sedentary (8 wks CON, n=8), 4 weeks exercise training (4 wks REG, n=8), and 8 weeks exercise training (8 wks REG, n=8). The rats were trained to climb a 1-m vertical incline (85-degree), with weights secured to their tails. They climbed 10 times, 3 days per week, for 8 consecutive weeks. Skeletal muscle was taken from the flexor halucis longus after the exercise training. After separating the total RNA, large-scale gene expression was investigated by beadarray (Illumina RatRef-12 Expression BeadChip) analysis, and qPCR was used to inspect the beadarray data and to analyze the RNA quantitatively. The detection p-value for the genes was p<0.01, the M-value {M=$log_2$(condition)-$log_2$(reference)} was >1.0, and the DiffScore was >20. In total, the expression of 30 genes significantly increased 4 weeks after the exercise training, and the expression of six genes decreased. At 8 weeks, the expression of five genes significantly increased and that of 12 decreased. Several genes are potentially involved in resistance exercise and muscle hypertrophy, including 1) regulation of cell growth (IGFBP1, PLA2G2A, OKL38); 2) myogenesis (CSRP3); 3) tissue regeneration and muscle development (MUSTN1, MYBPH); 4) hypertrophy (CYR61, ATF3, NR4A3); and 5) glucose metabolism (G6PC, PCK1). These results may help to explain previously reported physiological changes of the skeletal muscle and suggest new avenues for further investigation.

Development of Pedagogical Content Knowledge of Novice Secondary Science Teachers through Collaborative Reflection (초임 중등 과학교사들의 협력적 성찰을 통한 수업 전문성 발달)

  • Shin, Minkyoung;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.42 no.1
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    • pp.77-96
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    • 2022
  • This study investigated how collaborative reflection between novice secondary science teachers promoted the development of teaching professionalism. We intentionally selected research participants who shared sufficient rapport. Data were collected by videotaping the classes taught by participants, pre-talk, post-interviews and nine collaborative reflection processes. All data were transcribed and analyzed. Results indicated that all three teachers showed changes in teaching practice. Minyoung's practice involved a teacher-led lecture, but through collaborative reflection, she could create a learning environment to enhance students' power and ownership in her class. Emphasizing academic rigor, Soyoung used to teach content outside the scope of the curriculum, but through collaborative reflection, she became more considerate of students' understanding. Finally, in Jiyeon's classes inquiry activities and theoretical explanations were separated from each other. However, she repeated her efforts to improve her class after collaborative reflection, allowing students to construct explanations through activities. In this study, three factors that promoted the development of teachers' pedagogical content knowledge through collaborative reflection were identified. First, the different teaching orientations of the three teachers who participated in this study, promoted sharing of opinions through collaborative reflection. Second, reflection based on teaching practice enabled practical feedback on the class, which enhanced the development of teachers' pedagogical content knowledge. Third, the equal status and formation of rapport between the three teachers created an environment for productive reflection. These results suggest that future teacher education programs should target communities that can promote collaborative reflection based on teachers' teaching practice.

Pre-service Science Teachers' Understanding of Students' Misconceptions in Physics and Perceptions on "Teacher as a Researcher" through the Research Experience (예비 과학교사의 연구 수행 경험이 학생의 물리 오개념에 대한 이해 및 '연구자로서의 교사'에 대한 인식에 미치는 영향)

  • Ko, Yeonjoo;Lee, Hyunju
    • Journal of The Korean Association For Science Education
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    • v.34 no.5
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    • pp.449-457
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    • 2014
  • Recent studies have shown that teachers should have be aware of and understand students' misconceptions, which is one of the major components of PCK. However, teachers often have difficulties in understanding misconceptions and in applying appropriate instructional strategies to change misconceptions. Thus, we designed a method course for pre-service teachers (PSTs) adapting the concept of "teacher as researcher". In the course, PSTs conducted research to investigate students' misconceptions in physics. Twenty-five female PSTs participated in the study. They went through the research process including creating question items, administering items to their target populations, collecting and analyzing student responses, and writing a research paper. Data source included individual interviews with the PSTs, field notes during classroom observation and PSTs' research papers. The results were as follows. First, the PSTs confirmed students' misconceptions and learning difficulties in physics. They experienced discrepancies between their conjecture and research findings. Second, PSTs developed the sophisticated understanding of students' misconceptions and appropriate teaching strategies. Third, the research experience provided the PSTs opportunities to reexamine their physics content knowledge while creating items and explaining scientific concepts. They realized that physics teachers should develop sound understanding of physics concepts for guiding students to have less misconception. Lastly, they realized the necessity of being a teacher as a researcher.

A Case Study on the Relationship between Characteristics of SSI Teachers' Community and Development of Teacher Expertise (SSI 교사모임의 특성과 교사 전문성 발달과의 관련성에 관한 사례연구)

  • Chung, Hangnam;Ryu, Suna
    • Journal of The Korean Association For Science Education
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    • v.38 no.3
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    • pp.431-440
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    • 2018
  • The purpose of this study is to investigate the characteristics of the K Teachers' Community, which brought about changes in the perception of SSI education by teachers with experience in SSI, and to explore its relevance to the development of SSI professions. This is a case study that describes in depth the characteristics of the K teachers' community. The study conducted semi-structured as well as in-depth interviews with six teachers who have more experience in SSI education activities for over 20 years. The K teachers' community has three characteristics. First, the K teachers' community formed identity by discussing the nature of science and technology, which allowed teachers to share a common orientation toward the goals of science education. Second, the teachers who participated in the K teachers' community formed professionalism and confidence in SSI teaching in the course of producing, sharing, and spreading SSI through its various practices. Third, the K teachers' community is continuously growing by opening themselves to external communities and co-evolution through solidarity. The success of K Teachers' Community may inform other teachers how the community of teaching practices can develop and maintain, and in turn can help the members of the community develop their professional identity as teachers.

Influence of Ginsenosides on the Kainic Acid-Induced Seizure Activity in Immature Rats

  • Park, Jin-Kyu;Jin, Sung-Ha;Choi, Keum-Hee;Ko, Ji-Hun;Baek, Nam-In;Choi, Soo-Young;Cho, Sung-Woo;Choi, Kang-Ju;Nam, Ki-Yeul
    • BMB Reports
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    • v.32 no.4
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    • pp.339-344
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    • 1999
  • We studied the effects of ginsenosides in immature rats based upon the previous results that ginseng has a suppressive or anticonvulsive activity. To examine the suppressive effect of ginsenosides on kainic acid-induced seizures, the severities and frequencies were observed for 4 h after injection of kainic acid (KA; i.p., 2 mg/kg b.w.) using 10-day-old male Sprague-Dawley rats ($22{\pm}2\;g$). Protopanaxadiol saponins such as ginsenoside-Rb1 (Rb1), ginsenoside-Rb2 (Rb2), ginsenoside-Rc (Rc), and ginsenoside-Rd(Rd) generally reduced the seizure activities while protopanaxatriol saponins such as ginsenoside-Rg1 (Rg1) and ginsenoside-Re (Re) rather increased stereotypic "paddling-like" movements. When vinyl-GABA (v-G) was injected together with Rb1 or Rc, KA-induced seizure severities were additionally reduced only by the injection of Rc, but not by Rb1. The level of gamma isozyme of protein kinase C (PKC-${\gamma}$) in the hippocampus increased about three times as much as that of normal rats at 4 h after KA injection. The increased level of PCK-${\gamma}$ by KA was significantly reduced to about 35% by the coinjection with v-G alone, but it was not changed by v-G together with Rb1 or Rc. The increased level of PKC-${\gamma}$ at 4 h after injection of KA was not consistent with the reduction of seizure severities between Rb1 and Rc. These results suggest that Rc and Rb1 may reduce seizure severity independent of PKC-${\gamma}$ levels, and Rc may additionally act with v-G regarding the GABA metabolism during the stage of KA-induced seizures in the immature rats.

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Effect of Phorbol ester on $K^+$channel in an G292 osteoblast-like cell (G292 세포에서 $K^+$통로에 대한 phorbol ester의 효과)

  • Kim, Mi-Kyung;Park, Su-Byung
    • The korean journal of orthodontics
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    • v.32 no.3 s.92
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    • pp.227-234
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    • 2002
  • In order to investigate the action mechanism of protein kinase C on $K^+$ channel in osteoblastic cell, effects of phorbol 12, 13-dibutyrate on human osteoblast-like cells (G292) were studied by patch clamp technique with cell-attacked configuration. 111 this experiment, 45pS ion channel was dominant in G292 cell line according to their approximate conductances in symmetrical 140mM KCl saline at holding potential of 60mV. In torrent-voltage relationship, reversal potential was 5.5mV at the condition of potassium enriched saline in the pipette and -27 mV at the condition of standard extracellular saline In the pipette. Phorbol 12, 13-dibutyrate 10nM increased the open probability of 45pS channel and staurosporine, an inhibitor of protein kinase C, suppressed this effect. Phorbol 12,13-dibutyrate moved the reversal potential of 45pS channel to more negative potential and increased the single channel current at the same membrame potential. In order to check the activation of protein kinase C in G292 cell by phorbol 12,13-dibutyrate, western blot of protein kinase C was performed. Phorbol 12,13-dibutyrate $0.1{\mu}M$ translocated protein kinase C from cellular compartment to membrane compartment of the cell. These findings suggest that phorbol 12,13-dibutyrate, one of phorbol esters, activate 45pS channel In G292 cell and affect cell membrane potential, that regulate cellular function.

Pedagogical Content Knowledge and Predictor Variables in Science Teaching of Practicing Elementary Teachers (교사들의 과학 교과교육학지식과 예측변인)

  • Park, Sung-Hye
    • Journal of The Korean Association For Science Education
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    • v.23 no.6
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    • pp.671-683
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    • 2003
  • The purpose of study was to investigate practicing elementary teachers' pedagogical content knowledge and the significant predictors of their pedagogical content knowledge in science teaching. The PCK instrument was used to measure elementary teachers' pedagogical content knowledge. It consists of 6 factors to measure teachers' pedagogical content knowledge of 1)instructional methods, 2)representations, 3)contents, 4)evaluations, 5)students, and 6)curriculum. A questionnaire that consists of 7 questions regarding the teachers' degree, their number of years of teaching their choice of teaching science, their personal science teaching efficacy, their science teaching outcome expectation, their science instructional methods, and their attitudes toward teaching science, was also used to identify the information as to significant predictors of teachers' pedagogical content knowledge. A sample of 332 practicing elementary teachers participated in this study. To determine statistically significant predictors, Pearson's correlation coefficient and multiple regression methods were used to analyze the results. The results showed that the significant predictors of practicing elementary teachers' pedagogical content knowledge were their number of years of teaching, their science instructional methods, their personal science teaching efficacy and their attitudes toward teaching science. Further research of how teachers develop and construct their pedagogical content knowledge is recommended especially through the use of varied research methodologies that include qualitative methods.