The Widening Gap of Academic Achievement Between the Rich and the Poor in Korea

Sang-soo Chang 서울대학교 사회발전연구소 2022 Journal of Asian Sociology Vol.51 No.1

This study deals with the effects of parental socioeconomic status on children’s academic achievement, which is referred to as the socioeconomic gradient or as the socioeconomic achievement gap, in Korea. The study differs from previous ones on the same topic in two aspects: First, it views Korea’s socioeconomic achievement gap in the context of international comparison. Second, it investigates the temporal change of Korea’s socioeconomic gradient, which has taken place during the last two decades, and identifies reasons for such a change. Analyzing PISA (Programme for International Student Assessment) data, which the OECD has collected every three years since 2000, the study found the following: First, the socioeconomic gradient in reading and math literacy scores in Korea was lower in the early 2000s than that in other OECD countries. However, these have since approached or exceeded the OECD average in the late 2010s. Second, the socioeconomic gradient has increased in reading literacy during the last two decades, although it has not changed in math literacy during the same period. This implies that the inequality of academic achievement has deteriorated in Korea. The degeneration seemed to arise both from the increase of differentiation in secondary schools, which neoliberal governments have actively driven since 1995, and from the consequent growth of parents’ school choices.

Correlation between skeletal and dental changes after mandibular setback surgery-first orthodontic treatment

Chang-Hoon Rhee,Youn-Kyung Choi,Yong-Il Kim,Seong-Sik Kim,Soo-Byung Park,Woo-Sung Son 대한치과교정학회 2015 대한치과교정학회지 Vol.45 No.2

Objective: To investigate skeletal and dental changes after application of a mandibular setback surgery-first orthodontic treatment approach in cases of skeletal Class III malocclusion. Methods: A retrospective study of 34 patients (23 men, 11 women; mean age, 26.2 ± 6.6 years) with skeletal Class III deformities, who underwent surgery-first orthodontic treatment, was conducted. Skeletal landmarks in the maxilla and mandible at three time points, pre-treatment (T0), immediate-postoperative (T1), and post-treatment (T2), were analyzed using cone-beam computed tomography (CBCT)-generated half-cephalograms. Results: The significant T0 to T1 mandibular changes occurred ?9.24 ± 3.97 mm horizontally. From T1 to T2, the mandible tended to move forward 1.22 ± 2.02 mm, while the condylar position (Cd to Po-perpendicular plane) shifted backward, and the coronoid process (Cp to FH plane) moved vertically. Between T1 and T2, the vertical dimension changed significantly (p < 0.05). Changes in the vertical dimension were significantly correlated to T1 to T2 changes in the Cd to Po-perpendicular plane (r = ?0.671, p = 0.034), and in the Cp to FH plane (r = 0.733, p = 0.016), as well as to T0 to T1 changes in the Cp to Poperpendicular plane (r = 0.758, p = 0.011). Conclusions: Greater alterations in the vertical dimension caused larger post-treatment (T2) stage skeletal changes. Studying the mandibular position in relation to the post-surgical vertical dimension emphasized the integral importance of vertical dimension control and proximal segment management to the success of surgery-first orthodontic treatment.

Rat의 복강내에 투여한 5-fluorouracil-polyglycolic acid 제형이 장기에 미치는 영향에 관한 연구

강대영,송규상,최정목,노승무,정경수,오정연,김진향,양준묵,최선웅,이진호,조준식,민병무,김용백,김창식,박근성,김승영,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

For more effective intraperitoneal chemotherapy, the authers made 5-fluorouracil-polyglycolic acid composite disks(FU-PGA disks) with 5-fluorouracil and polyglycolic acid, a biodegradable polymer. We inserted the FU-PGA disk into the peritoneal cavites of Sprague-Dawley male rats, the control and three experimental groups; one FU-PGA disk insert group(300mg/kg), two FU-PGA disk insert group(600mg/kg), and three FU-PGA disk insert group(900mg/kg). The control group received a similar number of PGA disk inserts. A pharmacokinetic study was performed to measure the 5-fluorouracil concentration in the peritoneal fluid, blood, and tissues(liver, kidney and heart) at 24 hours, 72hours and 168 hours after insertion of the FU-PGA disk. Light and electron microscopic studies were done. The results were as follows: 1) The number of white blood cells and platelets decreased after FU-PGA insertion. The degree was proportional to the duration and amounts inserted. The change in the number of red blood cells varied slightly. 2) Light microscopically, slight changes were noted at 168 hours in the 3 disk insert group (900mg/kg). Mild fatty change and hepatocyte degeneration around the central veins of the liver were noted, with vacuolar degeneration in the proximal convoluted tubules of the kidney. 3) Electron microscopically,the liver showed focal increases of lipid droplets in the hepatocytes, and irregular nuclear membrane with focal nucleolar segregation of the fibrillar and granular elements. Also the double membranous structure of the hepatocytes and Kupffer cells was widened with bleb formation. The kidney showed wide separation of the nuclear double membrane in the proximal convoluted tubular cells and mesangial cells, with vacuolation and myelin figure formation in the mitochondria of the proximal convoluted tubular cells, at 72 hours and 168 hours in the 2 to 3 FU-PGA insert groups. The heart showed focal loss of cristae,vacuolation and myelin figure formation in the mitochondria of the 2 to 3 FU-PGA insert groups. In conclusion, despite the large amont of FU-PGA inserted, the histopathological changes in the liver, kidney and heart were slight, and consonant with the very low amount of 5-fluorouracil concentrations detected in the liver, kidney and heart. The above results suggest that the FU-PGA composite can serve as a new device for releasing drugs in a controlled manner and easily targeted to intraperitoneal organs. This device can improve the efficacy of intraperitoneal chemotherapy for gastric cancer.

Which Environmental Factors Caused Lammas Shoot Growth of Korean Red Pine?

Lee, Chang-Seok,Song, Hye-Gyung,Kim, Hye-Soo,Lee, Bit-Na-Ra,Pi, Jeong-Hoon,Cho, Yong-Chan,Seol, Eun-Sil,Oh, Woo-Seok,Park, Sung-Ae,Lee, Seon-Mi The Ecological Society of Korea 2007 Journal of Ecology and Environment Vol.30 No.1

Lammas growth, a rare phenomenon for Korean red pine (Pinus densiflora), occurred in 2006. Lammas shoots showed higher frequency and longer length in Seoul's hotter urban center than in urban boundary or suburban forest sites. Frequency and length showed a close correlation with urbanization density and vegetation cover expressed in NDVI. Air temperature in the late summer of 2006 was more than $1^{\circ}C$ higher than an average year. Of the predominant environmental signals that modulate bud flush, only temperature changed significantly during the year. Differences in temperature between the urban centers, urban boundaries and suburban forests correlated with varying land-use density. The rise in temperature likely spurred lammas growth of the Korean red pine. Symptoms of climate change are being detected throughout the world, and its consequences will be clearer in the future. Considerate interest in the responses of ecological systems to the variable changes is required to prepare for unforeseeable crises. Monitoring of diverse ecological phenomena at Long Term Ecological Research sites could offer harbingers of change.

농촌지도직공무원 지방직 전환 첫 해의 예비평가

김성수(Sung Soo Kim),최창욱(Chang Wook Choi),최영창(Young Chang Choe) 한국농촌지도학회 1997 농촌지도와 개발 Vol.4 No.2

The objectives of this study were 1) to evaluate the first year of localization of agricultural extension in Korea, 2) to present the development directions and implications of agricultural extension service in the next year of localization. The major results and implications were as follows. 1. The positive changes in localization were to establish local special projects and to work in agricultural extension without personnel changes. 2. The negative changes in localization were increase of unnecessary work load and decrease of morale because of lowered status. 3. The development directions were m cut back unnecessary work load, to rearrange an office, and to return to the national status of extension personnels.

암세포 증식에 대한 YB-1 안티센스 올리고핵산염의 영향

김명성 ( Myung Sung Kim ),이완식 ( Wan Sik Lee ),박창환 ( Chang Hwan Park ),주영은 ( Young Eun Joo ),김현수 ( Hyun Soo Kim ),최성규 ( Sung Kyu Choi ),유종선 ( Jong Sun Rew ),정영도 ( Young Do Jung ),김세종 ( Sei Jong Kim ),안봉환 대한내과학회 2006 대한내과학회지 Vol.71 No.3

목적: YB-1은 PCNA, DNA 중합효소 및 MDR 유전자 등의 전사인자로 작용한다. YB-1 유전자는 정상 어른의 간에서는 발현되지 않지만 태아의 간이나 재생 중인 간에서는 발현이 현저히 증가되어서 세포의 증식과 밀접한 관련이 있음이 보고되었다. 본 연구에서는 YB-1 유전자의 안티센스 올리고핵산염을 이용하여 YB-1의 발현을 억제함으로써 암세포 증식을 차단 할 수 있는지를 실험하고 암치료를 위한 유전자 요법으로서의 가능성을 알아보았다. 방법: 세포주로는 Chang liver, HepG2, CT-26 세포를 사용하였고, 사람의 정상세포로는 섬유아세포와 내피세포가 혼재된 조직을 사용하였다. YB-1 유전자의 안티센스 올리고핵산염으로는 YB-1 cDNA의 변역 시작 부위에 상보적인 21mer 올리고핵산염을 제작하여 사용하였다. 세포의 성장은 MTT assay를 이용하였고, 유전자 발현은 Northern blot으로 분석하였으며, 세포주기 변화는 propidium iodide로 염색하여 유식세포분석기로 분석하였다. 동물실험에서는 CT-26 세포를 1.0×10(5)개씩 Balb/c 생쥐의 피하에 접종하여 종양을 유도하였다. 종양이 유도된 Balb/c 생쥐에 YB-1 안티센스 올리고핵산염을 꼬리정맥이나 종양조직에 주사한 후 종양의 크기를 측정하여 종양억제 효과를 관찰하였다. 결과: YB-1 안티센스 올리고핵산염은 CT-26 세포에서는 50 nM 이상 농도에서 Chang liver와 HepG2 세포에서는 10 nM 이상 농도에서 세포주의 성장을 강하게 억제하였지만 정상 조직세포의 성장에는 아무런 영향을 미치지 않았다. 안티센스 올리고핵산염을 DOTAP에 담지한 경우 세포성장 억제에 미치는 효과가 안티센스 올리고핵산염 단독 처치 보다 강하였다. 이때 YB-1의 발현은 증식이 억제된 세포주(Chang liver 및 CT-26)에서는 감소하였으나 정상조직세포에서는 변화가 없었다. 증식이 억제된 세포주에서 세포주기를 살펴보면 초기에 S phase가 감소함을 관찰 할 수 있었다. 꼬리정맥이나 종양조직에 YB-1 안티센스 올리고핵산염을 주입 시 종양의 크기가 유의하게 감소하였다. 결론: 이상의 실험 결과 YB-1 안티센스 올리고핵산염은 암세포의 성장을 저해하며 종양 동물모델에서 종양의 성장을 억제할 수 있음을 시사하였다. Background: Human YB-1 is a transcription factor that binds to the inverted CCAAT box in the promoter region of a variety of genes such as PCNA, DNA polymerase and MDR. In this study we evaluated the effect of YB-1 antisense oligonucleotides on tumor cell growth. Methods: Chang liver, HepG2 and CT-26 cells were cultured as immortalized cell lines. The MTT (3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide) assay, Northern blot and flow cytometric analyses were used to determine cell growth, gene expression and cell cycle changes. In an animal model, CT-26 cells were injected into Balb/c mice to induce tumor; YB-1 antisense oligonucleotides were injected into the tail vein or tumor tissue of the mice; change of tumor size was then measured. Results: Phosphorothioated YB-1 antisense oligonucleotides suppressed the proliferation of the immortalized liver cells (Chang liver cells) and a variety of cancer cells (HepG2 and CT-26 cells); however, it did not inhibit normal cell growth. The DOTAP/antisense oligonucleotide mixture showed stronger effects on cell proliferation than did the antisense oligonucleotide alone. The YB-1 antisense oligonucleotide decreased specific expression of the YB-1 mRNA in the immortalized cancer cell lines. Flow cytometric analysis revealed that the inhibition of cell proliferation might have been due to a decrease in the S phase of the cell cycle. We found that in an animal tumor model, the administration of the YB-1 antisense oligonucleotide, in the vein or tumor tissues, decreased the tumor size significantly. Conclusions: These results suggest that the YB-1 antisense oligonucleotide may inhibit growth of a variety of cancer cells.(Korean J Med 71:293-301, 2006)

펠던크라이스 기법, 탄성밴드 운동 및 복합운동 적용이 현대무용전공자의 체간근력에 미치는 영향

김채수(Kim Chae-Soo),권혜영(Kwon Hye-Young),이원재(Lee Won-Jae),조창모(Jo Chang-Mo),김진환(Kim Jin-Hwan),주성범(Ju Sung-Bum),이미경(Lee Mi-Kyoung) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.1

This study is carried out to examine the effect of applying Feldenkrais method, elastic band training and combined training on trunk muscle. The subjects of this study were 32 modern dance majors and they were divided into four groups which consists of 8 peoples each, Feldenkrais method group(modern dance + Feldenkrais method), elastic band training group(modern dance + elastic band training), combined training group(modern dance + Feldenkrais method + elastic band training), and control group(modern dance). Measurement variables which are trunk muscle were measured before training, and after 4 and 8 weeks training and the results are as follow: In the left muscle strength change at Centaur 0°, Feldenkrais method group, elastic band training group and combined training group showed significant increase after 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group and combined training group had significant increase after 8 weeks training. In the left muscle strength change at Centaur 45°, Feldenkrais method group and combined training group showed significant increase after 8 weeks training compared to before training and after 4 weeks training. Also elastic band training group showed significant increase after 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group and elastic band training group significantly increased after 8 weeks training compared to before training. In the left muscle strength change at Centaur 90°, Feldenkrais method group and combined training group showed significant increase after 4 and 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group showed significant increase after 4 and 8 weeks training compared to before training, and elastic band training group significantly increased after 8weeks training compared to before training. In the left muscle strength change at Centaur 135°, there was no significant changes. In the right muscle strength change, elastic band training group and combined training group showed significant increase after 8 weeks training compared to before training. In the left muscle strength change at Centaur 180°, combined training group showed significant increase after 4 and 8 weeks training compared to before training. In the right muscle strength change, combined training group showed significant increase after 4 and 8 weeks training compared to before training. From above results, applying 8 weeks regular program of Feldenkrais method, elastic band training and combined training to modern dance majors showed positive changes on improvement of trunk muscle strength and physical strength. Also this study implemented to verify the effects of trunk muscle strength and body balance through supplementary training program, and showed the effects in the training group and control group after 8 weeks trunk muscle strengthening program. Feldenkrais method, elastic band training and combined training are very effective to improve trunk muscle strength of modern dance majors so that continuous implementation and application of these effective training program shall be provided for strengthening trunk muscle.

Long second toe: its nail and skin changes

( Geun-hwi Park ),( Woo-il Kim ),( Min-young Yang ),( Won-ku Lee ),( Tae-wook Kim ),( Sung-min Park ),( Hyun-joo Lee ),( Gun-wook Kim ),( Hoon-soo Kim ),( Hyun-chang Ko ),( Byung-soo Kim ),( Moon-bum 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2

Background: Nail can be affected by trauma, infection, and systematic disorders. In particular, the toe nails are exposed to the repeated and cumulative minor traumas, which usually result in thickened, splitted, and discolorated nails. Considering these, it can be inferred that the long second toe can be related to various nail and skin changes by repeated minor traumas such as friction in shoes, but the study or report on this topic hasn’t been done yet. Objectives: The purpose of this study was to introduce various nail and skin changes on long second toe. Methods: We analyzed the kinds of nail/skin changes of 50 patients with long second toe, enrolled at Pusan National University Hospitals (Busan and Yangsan) from 2013 to 2018. Results: There was no significant difference in the incidence of left and right toe and toenail, and 7 (14%) patients presented bilateral distribution. The most common nail change on long second toe was melanonychia (23, 46%), followed by subungual hematoma (15, 30%), onycholysis (2, 4%), subungual hyperkeratosis (2, 4%), onychomadesis (1, 2%), and retronychia (1, 2%). The most common skin change was corn (9, 18%), followed by paronychia (2, 4%). Twenty (20/50, 40%) patients also had other toe or toenail changes. Among them, the most common site was big toe/nail (13, 62%), and the most common change was subungual hematoma (8, 42%). Conclusion: Through this study, the dermatologists can recognize and diagnose the nail and skin changes of long second toe.

農民技術受容에 影響을 주는 要因의 比較分析 : 關係機關과 情報傳達媒體를 中心으로

鄭址雄,崔敏浩,金性洙,徐圭善,李昶植 서울大學校 農科大學 1984 서울대농학연구지 Vol.9 No.2

The purpose of the study was to analyze the variables affecting farmers' adoption process of agricultural innovations in Korea. Specific objectives of the study were to ; (1) review the adoption process and the variables associated with this process, (2) investigate the rate of adoption of selected agricultural innovations in the fields of rice production, animal husbandary and horticulture, (3) analyze communication media and change agencies or institutions which affected the adoption of agricultural innovations, and (4) identify the relations of the farmers' adoption and communication exposure behavior. Data for the study were collected from 393 cluster sampled farmers out of selected 17 rural villages in Korea. Five graduate students and three faculty members of Seoul National University participated in conducting interview with pre-tested questionnairs. The data were analyzed by HP 3,000 computer in the College of Agriculture, Seoul National University. Major statistical techniques used for the study were frequency distribution, chi-square and discriminant analysis. Statistical significance was tested at .05 level. The major findings of the study were as follows : 1. Variables associated with the agricultural adoption process were classified into the following six categories ; (1) perceived characteristics of agricultural innovations, (2) personality and characteristics of adopters, (3) the patterns of communication media or channels, (4) efforts of change agents. (5) priorities in agricultural development policies, and (6) characteristics of social system. 2. Rats of adoption were about 83% in application of silicate fertilizers on rice seed bed, 41% in feeding calf starter known as artificial milk to calves, 56% vinyl mulching practices in vegetable cultivation, and 67% in spreading raw rice straw on paddy land to improve soil conditions. 3. Time lag between awareness and adoption appeared to be about seven months in application of silicate fertilizers on rice seed bed, and about a year in feeding calf starter. 4. Change agent interpersonal communication revealed to be the most important factor affecting farmers' awareness in application of silicate fertilizers on rice seed bed, in feeding calf starter, and in spreading raw rice straw on paddy land, while localite interpersonal communication in vinyl mulching practices in vegetable cultivation. 5. Change agent interpersonal communication appeared to be the most important factor affecting farmers' adoption in application of silicate fertilizers on rice seed bed and in feeding calf-starter, Localite interpersonal communications were more important in vinyl mulching practices of vegetable cultivation and in spreading raw rice straw. Localite interpersonal communications were more important factor at adoption stage than at awarenss stage. 6. Agricultural extension agencies appeared to be the most important factor affecting farmers' adoption in application of silicate fertilizers on rice seed bed, in feeding calf starter, and in vinyl mulching practices. Based on the results of this study, the following are recommended for further development of agricultural extension services and effective adoption process of agricultural innovation. 1. The variables associated with the agricultural innovation decision process should be taken into consideration to improve effectiveness of change agencies or agricultural extension services. 2. Effective use of communication media along with the feedback messages from the change agency as well as client system be considered to increase effectiveness and meaningfulness of both systems. 3. Innovative agricultural research be continually sharpen its focus on the highest priority needs of client system by utilizing feedback from farmers through the communication link of change agents. 4. A long-term educational approach by using various communication media be emphasized, and regular field survey on innovation-decision process will prevent discontinuance of innovations.

한ㆍ일 도시가스산업의 생산성 비교분석

최인수(In Su Choi),도범성(Bum Sung Do),박창수(Chang Soo Park),박중구(Jung Gu Park) 한국가스학회 2009 한국가스학회지 Vol.13 No.2

본고는 21세기 들어 고유가와 기후변화협약에 대응하여 중요성이 더해지고 있는 한국과 일본의 도시가스기업의 생산성을 분석하였다. 맘퀴스트 생산성 지수(Malmquist Productivity Index: MPI)를 통해 1997년부터 2005년까지 한국 30개, 일본 5개 기업들의 재무제표를 활용하여 기간 전체로, 그리고 수요의 구조변화를 나타내었던 2000년을 기준으로 이전과 이후의 생산성을 평가하였다. 분석의 결과, 첫째, 1996년~2005년 전체 기간의 MPI 누적지수에서 한국의 도시가스산업이 일본보다 상위에 있는 것으로 분석되었다. 그러나 기간별로 본 MPI 개선효과는 일본의 경우 1997~2000년 동안 -1.03%에서 2001~2005년 동안에는 -1.72%로 근소한 차이를 나타낸 반면, 한국의 경우에는 전반기 0.37%(금융외환위기를 경험한 98년 제외시 0.80%)이었지만 후반기에 -0.60%로 악화된 것으로 나타났다. 둘째, 후반기 한국의 MPI 악화는 기술적 효율성 지수보다는 기술변화 지수가 전반기 -0.88%(98년 제외시 0.29%)에서 후반기 -1.29%로 크게 악화된 것에 기인하는 것으로 분석되었다. 이에 따라 한국의 도시가스사업은 2001년 이후 악화되고 있는 생산성 증가율과 악화의 요인이 되고 있는 기술변화를 개선하는 정책적 노력이 필요하다. This article makes a comparative analysis on the productivity in gas distribution industry between Korea and Japan, using Malmquist productivity index(MPI). The estimated MPI during 1997~2005 shows that the productivity of Korean gas distribution industry has been generally higher than that of Japanese gas distribution industry. But Korean MPI made a drastic change from positive improvement (+ 0.37) during 1997~2000 to severe deterioration (-0.60) during 2001~2005, while Japan MPI has seldom changed. This change of Korean MPI is analyzed to result from the worsening of technical change rather than technical efficiency change. According to this result, Korean gas distribution industry needs to improve the technical change.