• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.21-30
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• 1997

The present study reports the density, growth and production of a razor clam, Sinollovacula constricta, which is known to be one of the important fishreies catches from the Korean tidal flat. The annual yield reached to about 6,000 metric tons per year till 1994. The study was conducted on the Hwaseong tidal flat located on the central west coast, 40 kilometers south-west from Seoul. The annual yield of the razor clam in this area reached to about 50% of the total catch from the whole Korean coast. Samples were colleted monthly at 14 occasions from May 1992 to August 1993. Density of S. constricta ranged from 92~165 individuals per square meter during the study period. General trend of decreasing density was observed when the animal became older, but an exception was the year class of 1991 whose density was lower than that of 1990. The size of the shell was clearly separated into two classes during fall and winter (from September to February), however, the maximum frequency of the length of small size classes moved to right after February. It indicates a fast growth of young clams from spring to summer. Fast growth of the shell could also be examined by the growth curve. The shell growth of the whole life span was described by the von Bertalanffy equation of $L_t=89.3{\times}[1{\exp}\{-0.58{\times}(t+0.73\}]$. The growth in flesh dry weight was well fitted to the Gompertz growth model with the equation, $W_t=5.00{\times}{\exp}\{-4.31{\times}{\exp}(-0.043{\times}t)\}$. The clam lost about 30% of the body weight during spawning in August. The annual production calculated based on the data from September 1992 to August 1993 amounted to 150 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ which was 2~50 fold higher than those of other bivalves occurred in Korea. This estimate was patitioned by each year classes; 87.5 by 1992, 53.4 by 1991, 59.0 by 1990 and -30.0 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ by 1989 year class.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.151-167
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• 2017

The main objective of this study was to investigate the climatic impact of $PM_{10}$ concentration on the temperature change pattern in Busan Metropolitan City(BMC), Korea during 2001~2015. Mean $PM_{10}$ concentration of BMC has gradually declined over the past 15 years. While the highest $PM_{10}$ concentration was observed in spring followed by winter, summer, and fall on average, the seasonal variations of $PM_{10}$ concentration differed from place to place within the city. Frequency analysis showed that the most frequently observed $PM_{10}$ concentration ranged from $20{\mu}g/m^3$ to $60{\mu}g/m^3$, which accounted for 64.6% of all daily observations. Overall, the west-high and east-low pattern of $PM_{10}$ concentration was relatively strong during the winter when the effect of yellow-dust events on the air quality was weak. Comparative analyses between $PM_{10}$ concentration and monthly temperature slope derived from generalized temperature curves indicated that the decreasing trend of $PM_{10}$ concentration was associated with increases of annual temperature range, and $PM_{10}$ concentration had a negative relationship with the temperature slope of warming months. Overall, $PM_{10}$ concentration had a weak correlation with the annual mean temperature, but it had a significant, positive correlation with the winter season, which had a dominant influence on the annual mean temperature. In terms of energy budget, it has been known that the change in $PM_{10}$ concentration contributes to the warming or cooling effect by affecting the radiative forcing due to the reflection and absorption of radiant energy. The correlation between $PM_{10}$ concentration and temperature changes in the study area was not seasonally and spatially consistent, and its significance was statistically limited partly due to the number of observations and the lack of potential socioeconomic factors relevant to urban air quality.

• Tuberculosis and Respiratory Diseases
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• v.60 no.4
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• pp.404-411
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• 2006

Purpose : Multidrug-resistant tuberculosis (MDR-TB) is an emerging threat to human beings. However, there is little data on the current status of MDR-TB in Korea. This study investigated the current status of MDR-TB in Korea using a survey of all the data from drug susceptibility tests (DST) performed across the country over the last three years. Method : The DST results between Jan. 2000 and Dec. 2002 from 7 laboratories, which were in charge of all antituberculous DSTs across the country as of March 2002, were collected and analyzed to determine the actual number of drug-resistant or MDR-TB patients, annual trend, degree and pattern of resistance against anti-TB drugs, etc. Results : Six laboratories used the absolute concentration method for DST and one used the proportional method. 59, 940 tests had been performed over the 3 year study period. The number of DST performed annually was 18,071, 19,950, and 21,919 in 2000-2002, respectively. The number of resistant tuberculosis patients (resistant against at least one anti-TB drug) had increased by 16.9% from 6,338 in 2000 to 7,409 in 2002. The rate of resistant tuberculosis among all DST results was 35.1% in 2000, 34.5% in 2001, and 33.8% in 2002. The number of MDR-TB patients (resistant against at least both isoniazid and rifampin) showed an increasing trend (14.5%) from 3,708 in 2000 to 4,245 in 2002. Conclusion : Approximately 4,000 MDR-TB cases are newly identified by DST annually and the number is showing an increasing trend. This study suggests that in order to cope with the current MDR-TB situation, the DST methods will need to be standardized and more aggressive measures will be required.

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.630-646
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• 2020

In rural areas, nitrate-nitrogen (NO3-N) pollution caused by agricultural activities is a major obstacle to the use of shallow groundwater as domestic water or drinking water. In this study, the water quality characteristics of shallow groundwater in Hyogyo-ri agricultural area of Yesan-gun, Chungcheongnam-do province was studied in connection with land use and chemical composition of soil layer. The average NO3-N concentration in groundwater exceeds the domestic and agricultural standard water qualities of Korea and is caused by anthropogenic sources such as fertilizer, livestock wastewater, and domestic sewage. The groundwater type mainly belongs to Ca(Na)-Cl type, unlike Ca-HCO3 type, a general type of shallow groundwater. The average NO3-N concentration (7.7 mg L-1) in groundwater in rice paddy/other (upstream, ranch, and residential) area is lower than the average concentration (22.8 mg L-1) in farm field area, due to a lower permeability in paddy area than that in farm field area. According to the trend analysis by the Mann-Kendall and Sen tests, the NO3-N concentration in the shallow groundwater shows a very weak decreasing trend with ~0.011 mg L-1yr-1 with indicating almost equilibrium state. Meanwhile, SO42- and HCO3- concentrations display annual decreasing trend by 15.48 and 13.15%, respectively. At a zone of 0 to 5 m below the surface, the average hydraulic conductivity is 1.86×10-5 cm s-1, with a greater value (1.03×10-4cm s-1) in sand layer and a smaller value (2.50×10-8 cm s-1) in silt layer.

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.437-461
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• 1997

Because of a significant improvement in the economic situation and development of scientific techniques in Korea during the last 30 years, the life expectancy of the Korean people has lengthened considerably and as a result, the number of the elderly has markedly increased. Such an increase of the number of aged population brought about many social, economic, and medical problems which were never seriously considered before. This study was conducted to assess the trend of medical care utilization and medical expenditure of the elderly. The data of each patient in the study were taken from computer database maintained for administrative purpose by the Korea Medical Insurance Corporation. The study population was 132,670 who were 60 years old or more and registered in Korean Medical Insurance Corporation from 1989 to 1993. The study subjects were predominantly female(56.3%) and 10,000-20,000 Won premium group(50.6%). The following are summaries of findings : The total increase of the number of inpatient cases was 40.5% from 1989 through 1993. The average annual increase was 3.7% in inpatient medical expenditures per case, 4.4% in inpatient medical expenditures per day and 0.08% in length of stay per case from 1989 through 1993. Cataract was the most prevalent disease of 10 leading frequent diseases in all ages from 1989 through 1993. The case mix in 1993 compared to 1989 revealed that cataract and ischemic cerebral disease were increased whereas essential hypertension and pulmonary tuberculosis were decreased . The average annual increase of medical expenditures was 3.8% in general hospitals, 6.3% in hospitals and 2.4% in clinics. From 1989 through 1993, medical expenditures used by high-cost patients accounted for about 14% to 20% of all expenditures for inpatient care, while they represented less than 2.5% of the elderly population. Time series analysis revealed that total medical expenditures and doctor's fee for inpatient will be progressively increased whereas drug expenditures for inpatient will be decreased. And there will be no change in length of stay. Based on the above results, the factors increasing medical cost and utilization should be identified and the method of cost containment for the elderly health care should be developed systematically.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.20-28
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• 2012

Introduction: The objective of this research was to determine the incidence of oral cancer in Korea. Materials and Methods: The classifications of oral and maxillofacial cancer (OMFC) that we used are based on possible locations of OMFC: lip, tongue, mouth, salivary glands, tonsil, oropharynx, nasopharynx, hypopharynx, pharynx unspecified, and nose, sinuses. Results: 1) There were 2,848 OMFC cases, accounting for 1.6% of all cancers. The male to female ratio was 2.72:1. 2) The estimated crude rates (CRs) were 5.7 overall, 8.4 for males, and 3.1 for females. The age-standardized incidence rates (ASRs) were 4.6 overall, 7.3 for males and 2.3 for females. 3) The incidence of mouth cancer was highest. The mouth and salivary glands were the most frequent sites for cancer among males and females, respectively. 4) Patients who were 40 years or older accounted for 91% of OMFC cases, with the highest proportion of cases in the 60-69 year-old age group for both sexes. 5) Tongue cancer was the most prevalent OMFC overall. Nasopharyngeal cancer was highest among males, and salivary gland cancer was highest among females. 6) From 2004 to 2008, the relative 5-year survival rate of OMFC patients was 57.5%. There was a trend of increasing survival among OMFC patients during the study period. The survival rate for females (69.3%) was much higher than that for males (53.1%). Conclusion: Social and personal efforts should be required to increase the survival rates of OMFC patients and Korean national cancer management policy should establish new measures for economic and social management and support.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3653-3661
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• 2013

Along with rapid economic growth and enhanced agricultural productivity, particulate matter emissions in the northern cities of Thailand have been increasing for the past two decades. This trend is expected to continue in the coming decade. Emissions of particulate matter have brought about a series of public health concerns, particularly chronic respiratory diseases. It is well known that lung cancer incidence among northern Thai women is one of the highest in Asia (an annual age-adjusted incidence rate of 37.4 per 100,000). This fact has aroused serious concern among the public and the government and has drawn much attention and interest from the scientific community. To investigate the potential causes of this relatively high lung cancer incidence, this study employed Fourier transform infrared spectroscopy (FTIR) transmission spectroscopy to identify the chemical composition of the $PM_{2.5}$ collected using Quartz Fibre Filters (QFFs) coupled with MiniVol$^{TM}$ portable air samplers (Airmetrics). $PM_{2.5}$ samples collected in nine administrative provinces in northern Thailand before and after the "Haze Episode" in 2013 were categorised based on three-dimensional plots of a principal component analysis (PCA) with Varimax rotation. In addition, the incremental lifetime exposure to $PM_{2.5}$ of both genders was calculated, and the first derivative of the FTIR spectrum of individual samples is here discussed.

• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.69-79
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• 2020

Objective : To analyze trends in the incidence and treatment of diseases associated with ischemic stroke, namely, cerebral infarction (CI), cerebral arterial stenosis (CASTN), and moyamoya disease (MMD), based on Korean National Health Insurance Service (NHIS) data from 2008 to 2016. Methods : Data was extracted from the national health-claim database provided by the NHIS for 2008-2016 using International Classification of Diseases codes. The crude and age-standardized incidences of each disease (CI, CASTN without a history of CI, and MMD) were calculated; additional analyses were conducted according to age and sex. Trends in the number of patients undergoing treatment according to treatment method were analyzed for each disease using the Korean Classification of Diseases procedure codes. Results : In 2016, the total number of adults with newly diagnosed CI was 83939, reflecting a 9.4% decrease from that in 2008. The age-standardized incidence of CI in adults was 153.2 per 100000 person-years in 2016, reflecting a 37.2% decrease from that in 2008, while that of CASTN was 167.3 per 100000 person-years in 2016, reflecting a 73.3% increase from that in 2008. Among treated cases, the number of patients who underwent intra-arterial (IA) treatment, including IA fibrinolysis and mechanical thrombectomy, showed the most prominent increase, increasing at an annual rate of 25.8%. For CASTN, the number of cases treated with carotid artery stenting or balloon angioplasty (CAS) showed the most prominent increase, increasing at a rate of 69.8% over the 9-year period. For MMD, the total number of patients with newly diagnosed MMD and that with adult MMD demonstrated significantly increasing trends, while the number of pediatric patients with newly diagnosed MMD declined by 18.0% over the 9-year period. The age-standardized incidences of pediatric and adult MMD in 2016 were 2.4 and 3.4 per 100000 person-years, respectively. Conclusion : Although the incidence of CI showed a declining trend over a 9-year period, the number and proportion of patients treated for CI increased. Meanwhile, the incidence of CASTN and the number of patients treated for CASTN have demonstrated increasing trends since 2008. On the other hand, the number of patients diagnosed with pediatric MMD decreased, despite no significant change in the incidence. In contrast, the number of patients and the incidence of adult MMD increased. These trends reflect changes in the population structure, gains in the accessibility of imaging examinations, and the development of endovascular techniques.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.113-121
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• 2000

This study was aimed to provide an epidemiologic study so that we could accommadate their orthodontic needs adequately and to obtain the reliable quantitative information regarding the characteristics of orthodontic patients who visited the Department of pediatric dentistry, Chonnam National University Hospital from 1986 to 1999, October. The results were as follows. 1 The total number of orthodontic patients were 1,381(male 658, female 723) and the number of annual patients showed irregular trend and the number of male were slightly higher than that of female. 2. According to the investigation made by age group, the group of under 5 years, 6 to 7, 8 to 9, 10 to 11, 12 to 13 and above 14 years showed 8.4%, 29.6%, 34.3%, 21.2%, 5.7% and 0.8%, respectively. 3. The patients corresponding to primary dentition were 15.7% of total patients and mesial step, distal step and flush terminal plane were 83%, 4.6% and 12.4% respectively. By the way 82% of mesial step had anterior crossbite at the same time. 4. The patients corresponding to Angle classification were 84.3% of total patients and Class I malocclusion, Class II div. 1, Class II div. 2 and Class III was 34.7%, 34.6%, 2.1% and 28.6%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.906-914
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• 2009

The Korean Society of Animal Science (KSAS) was officially born on October 8, 1956 under the leadership of Professor Sang W. Yun of Seoul National University, Seoul, Korea a few years after the end of the Korean War. At that time, there were 0.9 million Korean native cattle, 1.3 million pigs and 8.9 million chickens in Korea. Per capita income for Korea (US$ 66) or China (US$ 59) was about 10% of Asian's average income (US$ 513) in 1956. Korea produced less than 0.2 million M/T of formula feed and consumed 6.1 kg/person/year of animal products. One could say that Korea was an example of an under-developed country in the world. Although the first issue of the Proceedings of the KSAS was published on October 28, 1958, regular quarterly journals of the KSAS were not published until March 1, 1969. Major activities other than publishing its journal were: holding an annual meeting and/or scientific forum at national or international level. The Asian-Australasian Association of Animal Production Societies (AAAP) was founded on September 1, 1980 at Kuala Lumpur, Malaysia with founding members from Australia, Indonesia, Japan, Korea, Malaysia, NZ, Philippines and Thailand. Thirteen AAAP Animal Science Congresses have been held in its 28 year history. Hosting countries were Malaysia (1980), Philippines (1982), Korea (1985), NZ (1987), Taiwan (1990), Thailand (1992), Indonesia (1994), Japan (1996), Australia (2000), India (2002), Malaysia (2004), Korea (2006) and Vietnam(2008). In 1988, significant progress of the AAAP was made by creating an official English journal of the AAAP entitled "Asian-Australasian Journal of Animal Sciences (AJAS)" under the initiative of the KSAS. This journal is now published monthly and distributed to more than 50 countries in the AAAP region and the world. It should be mentioned that the KSAS was able to successfully host the $3^{rd}$ AAAP Animal Science Congress in 1985 and the 12th in 2006, as well as the $8^{th}$ WCAP in 1998. During the last 50 years of KSAS history, per capita income of Korea increased to US$ 17,690 (268 fold), formula feed production increased to 15 million M/T (97 fold) and consumption of animal products increased to 105 kg/person/year (17 fold). Cattle, pig and chicken numbers also increased to 2.5 million (2.8 fold), 9 million (7.4 fold) and 119 million (13 fold). This trend was also found for China and Asia, even if the rate of growth was slightly lower than that of Korea. It is expected that a similar rate of growth in economics, animal numbers, formula feed production and animal protein intake will likely be achieved by other Asian countries in the $21^{st}$ century with somewhat lower rate of development than that of Korea.