• Title/Summary/Keyword: AGE ring

Search Result 246, Processing Time 0.03 seconds

Gravitational Instability of Rotating Isothermal Rings

  • Moon, Sanghyuk;Kim, Woong-Tae
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.41 no.2
    • /
    • pp.61.2-61.2
    • /
    • 2016
  • Nuclear rings at centers of barred galaxies exhibit strong star formation activities. They are thought to undergo gravitational instability when sufficiently massive. We approximate them as rigidly-rotating isothermal objects and investigate their gravitational instability. Using a self-consistent eld method, we first construct their equilibrium sequences specified by two parameters: ${\alpha}$ corresponding to the thermal energy relative to gravitational potential energy, and $R_B$ measuring the ellipticity or ring thickness. The density distributions in the meridional plane are steeper for smaller ${\alpha}$, and well approximated by those of infinite cylinders for slender rings. We also calculate the dispersion relations of nonaxisymmetric modes in rigidly-rotating slender rings with angular frequency ${\Omega}$ and central density ${\rho}_c$. Rings with smaller are found more unstable with a larger unstable range of the azimuthal mode number. The instability is completely suppressed by rotation when ${\Omega}$ exceeds the critical value. The critical angular frequency is found to be almost constant at $0.7(G{\rho}_c)^{1/2}$ for ${\alpha}$ > 0.01 and increases rapidly for smaller ${\alpha}$. We apply our results to a sample of observed star-forming rings and confirm that rings without a noticeable azimuthal age gradient of young star clusters are indeed gravitationally unstable.

  • PDF

Clinical Study of Inguinal Hernia in Children (소아 서혜부 탈장의 임상적 고찰)

  • Kim, Kyeung-Rae;Kim, Sung-Soo;Lee, Young-Taek;Park, Yong-Kee;Choi, Chang-Rok
    • Advances in pediatric surgery
    • /
    • v.4 no.1
    • /
    • pp.48-54
    • /
    • 1998
  • A total of 335 pediatric inguinal hernias were analyzed at the Department of General Surgery, St. Benedict Hospital, for last 10 years (1986 to 1995). Male patients were predominant(2.25 : 1), and 78.2 % were under 2 years of age. Right side was 1.63 times more frequent than the left. Among the 19 cases of incarcerated hernias, 84 % could be safely reduced preoperatively. Twelve cases(3.6 %) were repaired by the Bassini procedure and 21 cases(6.3 %) by internal ring repair. The majority (90.1 %) however did not require a posterior wall reconstruction. Bilaterality was found in 25 cases(7.5 %), and in 8 cases(2.4 %) subsequent contralateral hernia developed after primary ipsilateral repair. Postoperative complication occurred in 15 cases(4.5 %); scrotal seroma and/or hematoma(3%), wound infection(0.6 %), and pneumonia(0.9 %). In order to reduce the incidents of complications, children with inguinal hernias should be treated by a pediatric surgeon.

  • PDF

Ecologically Sustainable Management of Short-necked Clam, Ruditapes philippinarum, on the Coast of Yeongi at Tongyeong, Korea (통영 연기해역의 바지락자원 적정관리에 관한 연구)

  • Cho, Sang-Man;Jeong, Woo-Geon;Lee, Sang-Jun
    • The Korean Journal of Malacology
    • /
    • v.24 no.3
    • /
    • pp.189-197
    • /
    • 2008
  • In order to develop the sustainable ecological management, short-necked clams, Ruditapes philippinarum, were collected from Yoengi coast in Tongyoeng, Korea. The growth of the clam was estimated as: $L_f=68.08{\cdot}(1-e^{-0.145(t+0.324)})$ from ring radius composition of shell. Instantaneous co-efficiency of total mortality and natural mortality were calculated as: 0.991/year and 0.494/year, respectively. The age of the clams from the first capture was estimated to be 3.28. The total biomass was estimated to be 212 MT in the fisheries area (6.4 ha). Applied by these parameters, the annual recruit biomass and the current yield per recruit were calculated to be 649.5 individual/$m^2$ and $0.7\;g/m^2$, respectively. The current fishing intensity was much lower for maximum sustainable yield and acceptable biological catch. Although higher yield per recruit could be achieved by increasing fishing intensity, it is favorable to retain the current fishing intensity because of the unique fishing attitude on Yeongi coast in Tongyoeng, Korea.

  • PDF

The Surrealistic Formative Characters of Modern Costume (현대복식의 초현실주의적 조형성)

  • 형승희;은영자
    • The Research Journal of the Costume Culture
    • /
    • v.2 no.2
    • /
    • pp.415-443
    • /
    • 1994
  • This thesis, drastically breaking from the prior form of art, searched mutual relationship between surrealism centering around surrealism which tried to liberate the spirit of humanbeing by investigating internal world of the humanbeing. That is to say, it is the purpose of this thesis to study the relationship between artistic trend and costume by grasping how the artistic trend of an age was specifically accepted and expressed to the modern costume as the foundation of fashion. Followings are the searched results for searching mutual relationship of the surrealism and modern costume. At first, surrealism made it possible from modern costume to an expression of formative art, and at the same time emerge from existed uniform costume, and thus presented new possibility to the harmony of costume and art with fresh and avant-garde sense. Second, by being applied the expressing method of depaysement which could materialize surrealistic image to the modern costume from various angels, and thus it suggested new aesthetic conception different from general conception of the traditional costume. Third, with regard to modern costume, introduction of various object due to thought of surrealism was a new and innovative attempt, and thus it suggested infinitive possibility of creation. So, it suggested that we could thrown away a fixed idea and that every objects could be moulded. As the result of the afore-said, wide application of the idea and formative feature of surrealism with regard to modern costume did not only ring the diversification and individualization of the costume escaped from the past traditional idea, but also at the same time prepared modern costume with the moment to develop as a formative arts.

  • PDF

The Rare and Challenging Presentation of Gastric Cancer during Pregnancy: A Report of Three Cases

  • Pacheco, Sergio;Norero, Enrique;Canales, Claudio;Martinez, Jose Miguel;Herrera, Maria Elisa;Munoz, Carolina;Jarufe, Nicolas
    • Journal of Gastric Cancer
    • /
    • v.16 no.4
    • /
    • pp.271-276
    • /
    • 2016
  • Pregnancy-associated gastric cancer is extremely rare. In many cases, it is diagnosed at an advanced stage because the symptoms during pregnancy are generally overlooked. We report three cases of gastric cancer during pregnancy with various outcomes. The first case included a patient with stage IV gastric cancer who received palliative chemotherapy. This patient had a preterm birth and died 7 months after diagnosis. The second case received neoadjuvant chemotherapy during pregnancy and a total gastrectomy was performed after delivery. She then received adjuvant chemoradiotherapy. This patient developed pulmonary metastasis and died of recurrence 41 months after surgery. In the third case, a distal subtotal gastrectomy was performed at week 14 of pregnancy, with no complications. The patient received adjuvant chemoradiotherapy. She is currently without recurrence 14 months after surgery. In patients with pregnancy-associated gastric cancer, treatment decisions are predominantly influenced by clinical stage and gestational age at diagnosis.

A Computer Program for Stem Analysis (수간석해(樹幹析解)의 전산화(電算化) 프로그램 개발(開發))

  • Cho, Eung Hyouk
    • Journal of Korean Society of Forest Science
    • /
    • v.69 no.1
    • /
    • pp.6-12
    • /
    • 1985
  • A computer program for stem analysis has been prepared by using BASIC language. Annual-ring counts and other input data can be directly entered for necessary calculation, and outputs are data lists, cross-section areas, age-height relationships, growth rates, total, annual, and mean increments of height, D.B.H. and volume for an individual tree. The sectional log volumes are calculated by Huber's formula, and the growth rates by Pressler's in this program. A copy of the program listing is in appendix I.

  • PDF

Cor Triatriatum with Coronary Artery Disease in an Old Man -A case report- (고령환자에서 관상동맥 질환을 동반한 삼심방심의 수술치험 -1예 보고-)

  • 천종록;이응배;조용근;장봉현;이종태;김규태
    • Journal of Chest Surgery
    • /
    • v.32 no.1
    • /
    • pp.58-61
    • /
    • 1999
  • Cor triatriatum is a rare anomaly in old age. This is a case report of a 66 year-old man who had been preoperatively diagnosed as coronary artery disease and cor triatriatum. The operative findings revealed that the left atrium had an intra-atrial septum with one small opening 10mm in diameter, the upper compartment received both pulmonary veins, and there were no other anomalies like anormalous pulmonary venous connection or atrial septal defect. The patient successfully underwent open heart surgery ; the anomalous septum was resected, the mitral valve was reconstructed using French technique with Carpentier-Edwards ring, and coronary artery bypass grafting was performed.

  • PDF

A Study on the Nail Size Measurement of Korean Adult Women -Focused on women in their 20s, 30s and 40s-

  • Lee, Eunsil;Kim, Eun-Sil
    • Journal of Fashion Business
    • /
    • v.22 no.3
    • /
    • pp.67-74
    • /
    • 2018
  • Korean nail-beauty is mainly concentrated on women in their 20s and 40s. The purpose of this study is to investigate the structure and characteristics of nails based on the literature and to measure the nail size of adult women in their 20s to 40s as an empirical study. The purpose of this study is to utilize the measurement results as basic data for the standardization of nail size through comparative study with previous studies. For the study method, 150 (50 for each age group) adult female in 20 ~ 40 years with cuticle removed for 30 days from September 17 to October 16, 2017 were measured. As the result, As a result of measurements, the width of the nail was almost similar to that of the researcher. However, the thumb was 1.01 mm longer than the results of the previous researchers. The index nail was 1.12 mm longer, the middle nail was 0.82 mm longer, and the ring nail was 1.3 mm longer than the previous study.

Study on natural short-necked clam, Ruditapes philippinarum, stocks in Yeongheung coast of Wando Island, Korea (완도 영흥지선 연안의 천연 바지락 자원에 대한 연구)

  • Cho, Sang-Man;Lee, Jong Hwa
    • The Korean Journal of Malacology
    • /
    • v.28 no.2
    • /
    • pp.109-116
    • /
    • 2012
  • In order to understand the effect of introduction of oyster rack culture on natural short-necked clam, Ruditapes philippinarum, stock, we investigated the status of natural clam stock prior to introduction of oyster rack culture at Yeongheung Coast of Wando Island. The growth equation of the clam was estimated as: $L_t=61.46{\cdot}(1-e^{-0.172(t+0.155)})$ from ring radius composition of shell. Instantaneous coefficient of total mortality and natural mortality were calculated as: 2.4087/year and 0.478/year, respectively. The age at first capture was estimated to be 2.55 year. The total biomass was estimated to 3.23 ton in the bed (0.8 ha). Applied by these parameters, the annual recruit biomass and the current yield per recruit (Y/R) was corresponded to $114.7individuals/m^2$ and $92.0g/m^2$, respectively. Maximum sustainable yield (MSY) was estimated 0.77 ton/year which was close to annual catches, 0.74 ton/year, in the area.

Vegetation Structure Analysis of Urban Forest -The Case of Namsan in Kyungju- (도시림의 식생구조분석 -경주 남산을 중심으로-)

  • 이영경;최송현
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.28 no.3
    • /
    • pp.13-24
    • /
    • 2000
  • In urban area, urban forests work as an ecological center that mitigates the environmental pollution of the area. In order to maintain the ecological function of a forest, the management method should be established based on ht through investigation of the vegetation structure of the forest. In this study, the vegetation structure of Namsan in Kyungju area was investigated in order to study the ecological value of Namsan and to suggest a desirable management alternative. 21 plots were selected as survey areas. Using the TWINSPAN technique, the forest of Namsan was classified into four communities: Quercus serrata community(I), Castanea crenata-Q. serrata-Q. mongolica community(II), Pinus densiflora community(III) and P. densiflora-P. rigida-Robinia pseudoacacia community(IV). The survey results were summarized by five: 1) the distribution of vegetation showed 2) P. densiflora was the absolutely dominant species in Namsan, 3) number of the average species was 12.6$^{\circ}$$\pm$3.1, 4) number of individual was 131.1$^{\circ}$$\pm$47.8 per a plot(100$m^2$), 5) the results of annual ring analysis revealed that the age of P. densiflora in Namsan was about 3 0$^{\circ}$~60$^{\circ}$years old. From the above results, it was found out that the forest has two problems. One thing is maintenance of P.densiflora against succession, another is artificial forest dispersion. The problems of Namsan forest management will be solved with further studies related.

  • PDF