• Journal of Environmental Science International
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• v.11 no.4
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• pp.347-353
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• 2002

This study was conducted to investigate the characteristics of chloramination as a secondary disinfection in a drinking water distribution system. At the range from pH 6 to pH 8, monochloramine was predominant with a trace of dichloramine, and the free chlorine was detected after breakpoint. At $25^{\circ}C$, the breakpoints of pH 6, 7 and 8 appeared when the weight ratios of chlorine to ammonia nitrogen were 11:1, 9:1 and 10:1 respectively, and the peak points on the breakpoint curves at pH 6, 7 and 8 were in the Cl$_2$ / NH$_3$-N ratio of 9:1, 6:1 and 5:1 respectively. As pH increased from 6 to 8, maximum point of monochloramine on the breakpoint curve was moved from 7:1 to 5:1 in the weight ratio of chlorine to ammonia nitrogen. The maximum concentration of monochloramine was formed at the pH values of 7~8 and in the Cl$_2$ / NH$_3$-N ratio below 5:1. As the Cl$_2$/NH$_3$-N ratio increased and the pH lowered, chloramines decay proceeded at an increased rate, and residual chloramines lasted longer than the residual free chlorine. The monochloramine and the dichloramine were formed at pH 6, and then the dichloramine continued increasing with contact time.

• Research in Community and Public Health Nursing
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• v.11 no.2
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• pp.499-512
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• 2000

The number of deliveries by cesarean section has increased internationally. However, The cesarean section rate is different by country to country. It is because each country has different social and cultural background and. practices its unique delivery policies. Hence, it is very important to understand the uniqueness that one country faces related with the cesarean section. In Korea, there have been many researches on the clinical. maternal. hospital and community factors and so on. However, few studies have attempted to reveal the physician factors in Korea because it is difficult to approach hospital records. So, in this study, the physician factors that influence the increase of cesarean section rate in Korea was investigated, and preliminary research agenda for policy establishment to keep the cesarean section rate from excessive increase was provided. In this study, all 2744 cesarean section deliveries performed by 36 physicians at the hospital was considered. and detailed delivery records of 12 months selected randomly from January 1996 to August 1998 was reviewed retrospectively. Chi-square analysis is used to examine the homogeneity of distribution of maternal, fetal, and clinical factors. In addition, multiple regression analysis is used to examine the effect of physician characteristics on the cesarean section rate. Physician characteristics as independent variable and the cesarean section rate as dependent variable was put in this analysis. Follows are the results of this study. 1) Total cesarean section rate is 34.8%. primary cesarean section rate is 12.5 % and repeated cesarean section rate is 22.3 %. Among the indications for the primary cesarean section, 15.6 % is for breech presentation. 40.2 % is for dystocia. 7.6 % is for fetal distress. and 36.6 % is for others. 2) There is positive correlation between physician's age and the cesarean section rate (p<0.001). And statistically significant correlation is found between the physician's educational attainment and the cesarean section rate (p<0.001). A physician with Ph.D degree has lower cesarean section rate than a physician with B.A only and M.A. degree (p<0.001). However. physician's gender, location of graduated university. position at the hospital, and the religious belief were not shown statistically significant relations with the cesarean section rate. 3) Among all cesarean sections in this study, only 15.4 % is performed during weekend. While 18.2 % is performed on monday only. This suggests that physicians may not prefer weekend operation of cesarean section. In addition, 86.1 % among all cesarean section operations is performed from 6 a.m. to 6 p.m. So the cesarean section rate could be related with a day of the week and a time of the day. From this results. there is a possibility that the physicians' personal comfort may influence the cesarean section rate.

• Ecology and Resilient Infrastructure
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• v.10 no.1
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• pp.11-19
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• 2023

Alien species are known to threaten regional biodiversity globally, which has increased global interest regarding introduction of alien species. The Ministry of Environment of Korea designated species that have not yet been introduced into the country with potential threat as alert alien species to prevent damage to the ecosystem. In this study, potential habitats of Esox lucius and Maccullochella peelii, which are predatory and designated as alert alien fish, were predicted on a national basis. Habitat suitability was evaluated using EHSM (Ecological Habitat Suitability Model), and water temperature data were input to calculate Physiological Habitat Suitability (PHS). The prediction results have shown that PHS of the two fishes were mainly controlled by heat or cold stress, which resulted in biased habitat distribution. E. lucius was predicted to prefer the basins at high latitudes (Han and Geum River), while M. peelii preferred metropolitan areas. Through these differences, it was expected that the invasion pattern of each alien fish can be different due to thermal preference. Further studies are required to enhance the model's predictive power, and future predictions under climate change scenarios are required to aid establishing sustainable management plans.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.35-50
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• 1999

The relationship between floristic composition and soil environmental conditions was investigated in the forest vegetation of Mt. Paekun. The forest vegetation unit of Mt. Paekun was divided into six plant communities by Zurich-Montpellier method, such as Quercus mongelica community (Typical subcommunity, Rhododendron schlippenbaohii subcommunity), Q. variabilis community, Fraxinus rhynchophylla community, Pinus densiflora community, Larix Eeptolepis community and Pinus koraiensis community. Q. mongolica community group was distributed at the altitude over 500 meter, Q. variabilis and P. densiflora communities appeared on the southwestern slope at the altitudes of 600 ~ 700 m and 290 ~ 700 m. However, L. leptolepis and P. koraiensis plantation were distributed at lower altitude, on hillside or around homestead. The DBH class distribution of dominant species in each community showed that Q. mongolica had 10.9 individuals/a at 6~10 cm class, Q. variabilis 2.5 individuals/a at 11~15 cm class, P. densiflora 1.8 individuals/a at 26~30 cm class, F. rhynchophylla 3.3 individuals/a at 2~5 cm class, and L. leptolepis 5.9 individuals/a at 11~ 15 cm class. Q. mongolica and Q. variabilis communities showed a stable bell-shaped pattern of distribution. The contents of organic matters and soil water, and cation exchange capacity of the soil increased, and the pH decreased as the altitude gets higher increased altitude at the each communities. The contents of the soil water and organic matters of the forest soil collected in Q. mongolica community were in the 17.81% to 51.20% and 5.51% to 14.90%, respectively. These tendency is similar to the contents of N, P and K, but those of Ca, Mg, and CEC was lower than in other communities. Cation exchange capacity was suspected to be correlated to the pH. The hypothetical successional sere of the forest vegetation of Mt. Paekun is as follows: Pinus densiflora community longrightarrowQ. variabilis community longrightarrowQ. mongolica community.

• Journal of Preventive Medicine and Public Health
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• v.3 no.1
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• pp.97-110
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• 1970

This survey was conducted to evaluate not only the present status of health center directors-their personal histories, their will to private practice in the future, their responses to governmental policies, -but also the distribution of doctorless myons, budget and subsidy, and director's opinions to the enhancement of health center activities. This survey questioned 116 health center directors and 16 health personnel from August to October of 1970 and obtained the following results; 1) The average ages of directors of kun, city, and total health centers were $43.2{\pm}7.8,\;42.1{\pm}7.7,\;and\;42.9{\pm}10.3$ respectively. 2) The average family sizes of directors of kun, city, and total health centers were $5.6{\pm}2.7,\;5.6{\pm}2.1,\;and\;5.6{\pm}2.6$ respectively. 3) Directors holding M. D. degrees were 79.3%, those holding qualified M. D. degrees ('approved director') were 20.7%. 4) M. P. H., M. S., and Ph. D. holders were 6.0%, 6.1%, and 4.3% respectively. 5) The average duration of present directorship in kun and city were 30.2 months and 20.4 months respectively. 6) The majority of directors had been employed in related fields before assuming current position : directorship at other health center 26.7%, army 22.4%, health subcenter 21.6%, private practice 19.0%. 7) Average length of directorship is 41.8 months. Average length of public health career, including health subcenter and present position, is 56.5 months. 8) Both rural and urban experience in health centers for regular directors is 16.3% and for approved directors, 12,5%. A total of 15.5% of all survey directors had experience in both rural and urban health center. 9) A total of 70.7% of health center directorships were staffed by local doctors. 10) Nearly 40% wanted to quit the directorships within 3 years and 60.3% had already experienced private practice. 11) Of the regular directors 17.4% felt strongly about devoting their lives to public health fields, but only 4.1% of the approved approved directors felt so. 12) There wire 432 doctorless myons among 996 respondent myons and 4.5 doctorless myons per kun. 13) The percentage of doctorless myon by Province are as follows, Cholla buk-do 57.2%, Cholla nam-de 55.0%, Kyungsang nam-do 52.0%, Kyungsang buk-do 49.7%, Chungchong but-do 42.4%, Kyonggi-do 32.9%. Cheju-do 30.8%, Kangwon-do 25.8%. 14) Two thirds of health critters have experienced the abscence of the director for a certain period since 1966 and the average span of the abscence was 18.2 months. 15) The percentage of doctorless myons increased proportionally with the span of the director's abscence. 16) The average budgets of health centers, kun, city and ku, were $W15.03\;million{\pm}W4.5\;million,\;W22.03\;million{\pm}W17.80\;million,\;W13.10\;million{\pm}W7.9\;million$ respectively. 17) Chunju city had the highest health budget per capita(W344) while Pusan Seo ku had the lowest(W19). 18) Director's medical subsidies are W30,000-50,000 in kun, and roughly W20,000 in city. 19) The older of priority in health center activities is T.B. control(31.1%), Family Planning and M. C. H.(28.0%), prevention of acute communicable disease and endemic disease (18.2%) and clinical care of patients(14.3%). 20) Nearly 32% opposed in principle the governmental policy of prohibiting medical doctors from going abroad. 21) Suggestions for immediate enhancing the position of director of health centers and subcenters: (1) Raise the base subsidy (48.2%), (2) Provide more opportunities for promotion (20.7%), (3) Exemption from army services(12.1%), (4) Full scholarship to medical students for this purpose only (7.8%). 22) A newly established medical school was opposed by 56.9% of the directors, however 33.6% of them approved. 23) Pertaining to the division of labor in Medicine and Pharmacy, the largest portion (31.9%) urged the immediate partial division of antibiotics and some addictive drugs to be given only by prescription. 24) More than half wanted a W70,000 level for the director's medical subsidies, white 36.2% stated W50,000. 25) Urgently needed skills in the kun are clinical pathologist (38.6%) and doctor (health center director) (25.5%); while in the city nurse (37.1%), doctors(clinical)(31.4%) and health educators(14.4%) are needed. 26) Essential treatment for the better health center administration; raising the base subsidy (22.7%), obtaining the power of personal management (19.3%) and the establishment of a Board of Health (14.3%). etc.