• Korea journal of population studies
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• v.29 no.3
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• pp.51-72
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• 2006

In Korea, most studies have used the conventional Wolfbein and Wool method, which cannot be applied to women's work-life table because of bimodality and/or M curve of female labor force participation. The increment/decrement work-life table method, however, is equally applicable to both men and women, but requires individual data on employment transition. This paper demonstrates that the Garfinkle-Pollard method is the same as the increment/decrement work-life table method developed by Hoem, Schoen and Woodrow and adopted by BLS. The merit of Garfinkle-Pollard method is to produce work-life table using labor force participation rate without individual employment transition. This paper applies the Garfinkle-Pollard methods to the estimation and projection of work-life of Korean labor force for the period of 2000-2050, using the abridged life tables provided by Korean National Statistical Office and a projection of labor force participation rates. The work-life expectancy at 65 is 5.8 years for men and 4.1 years for women in 2000, and it increased to 7.7 years for men and 5.1 years in 2050. However, differences in work-life expectancy are found depending on the data processing of elderly labor force participation and mortality assumption. Detailed data on elderly labor force participation and further study on future mortality are required to estimate and project more accurate work-life expectancy.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.33-39
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• 2019

The upsurge of population, internal migration, economic activities and developmental works has brought significant land use and land cover (LULC) change over the period of 1990 and 2010 in the Bagmati basin of Nepal. Along with alteration on various other ecosystem services like water yield, water quality, soil loss etc. carbon sequestration is also altered. This study thus primary deals with evaluation of LULC change and its impact on the soil carbon storage for the period 1990 to 2010. For the evaluation, InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Carbon model is used. Residential and several other infrastructural development activities were prevalent on the study period and as a result in 2010 major soil carbon reserve like forest area is decreased by 7.17% of its original coverage in 1990. This decrement has brought about a subsequent decrement of 1.39 million tons of carbon in the basin. Conversion from barren land, water bodies and built up areas to higher carbon reserve like forest and agriculture land has slightly increased soil carbon storage but still, net reduction is higher. Thus, the spatial output of the model in the form of maps is expected to help in decision making for future land use planning and for restoration policies.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.96-106
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• 2022

Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.42-51
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• 2020

This study was performed to support the 6th forest basic planning by Korea Forest Service as predicting the change of forestland area by the transition of land use type in the future over 35 years in South Korea. It is very important to analyze upcoming forestland area change for future forest planning because forestland plays a basic role to predict forest resources change for afforestation, production and management in the future. Therefore, the transitional interaction between land use types in future of South Korea was predicted in this study using econometrical models based on past trend data of land use type and related variables. The econometrical model based on maximum discounted profits theory for land use type determination was used to estimate total quantitative change by forestland, agricultural land and urban area at national scale using explanatory variables such as forestry value added, agricultural income and population during over 46 years. In result, it was analyzed that forestland area would decrease continuously at approximately 29,000 ha by 2027 while urban area increases in South Korea. However, it was predicted that the forestland area would be started to increase gradually at 170,000 ha by 2050 because urban area was reduced according to population decrement from 2032 in South Korea. We could find out that the increment of forestland would be attributed to social problems such as urban hollowing and localities extinction phenomenon by steep decrement of population from 2032. The decrement and increment of forestland by unbalanced population immigration to major cities and migration to localities might cause many social and economic problems against national sustainable development, so that future strategies and policies for forestland should be established considering such future change trends of land use type for balanced development and reasonable forestland use and conservation.

• Journal of Animal Science and Technology
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• v.60 no.4
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• pp.7.1-7.5
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• 2018

Background: Mice are widely accepted research models of great clinical significance. Maintenance of laboratory mice breed is an essential aspect for performing research activities in various fields of science. Infanticide is one of the prominent causes of litter loss during maintenance of laboratory mice stock. The present study is an effort to monitor the effect of change in ambient temperature of female mice below the normal range on cannibalism and infanticide during early postparturition phase. Adult female Swiss albino mice have been divided into two groups of control and treatment. On the day of litter group one was maintained under controlled temperature conditions (minimum $20^{\circ}C$ to maximum $23^{\circ}C$) throughout, while female mice belong to group two have been exposed to variation of room temperature (maximum $15^{\circ}C$ to minimum $10^{\circ}C$ for two nights and one day) until 36 h postparturition. Results: The effects of temperature changes were observed on the infanticide behaviour of dams along with the survival of pups in early postparturition phase till 36 h after delivery. The significant statistical difference (P < 0.05) was reported in infanticide behaviour of dams when control and treatment group was compared. It is observed that decrement in surrounding temperature promotes decrement in the ambient body temperature of dams during early postparturition. It is proposed that alteration of hypothalamic homeostasis due to temperature change induces cannibalism and infanticide behaviour. Lack of thermoregulation during early postparturition creates the sense of insecurity, in-satiety, anxiety and stress. Conclusions: Authors strongly recommend the maintenance of body and surrounding temperature to prevent infanticidal behaviour and cannibalism within Swiss albino mice population. Further investigations are advisable to authenticate the active behavioural and biochemical pathway behind the phenomena.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.120-127
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• 2018

The rural labor force has gradually been decreasing due to the decrement of the farm population and the increment of the aging population. To solve these problems, it is necessary to develop and study autonomous agricultural machinery. Therefore, analyzing the dynamic behavior of vehicles in an autonomous agricultural environment is important. Until now, most studies on agricultural machinery, especially on ground vehicle dynamics, have been done by field tests. However, these field test methods are time consuming and costly with seasonal restrictions. A research method that can replace existing field test methods by using simulations is needed. In this study, we did basic research analyzing the effect of the travelling speed of a tractor on tire slip using simulation software. A tractor simulation model was developed based on field conditions following a straight path. The simulation was done for three ranges of speed: 20 - 30 km/h (considered the normal travelling speed range), 6 - 8 km/h (considered the plow tillage speed range) and 2 - 4 km/h (considered the rotary tillage speed range). The results of the simulation show that the slip ratio and slip angle values tended to increase as the traveling speed range of the tractor decreased. From the simulation results, it can be concluded that at low tractor speeds, it becomes more difficult to control the vehicle path. In future research, simulations will be done with various work environments such as a curved path as well as with various friction coefficient conditions, and the simulation results will be experimentally verified by applying them to an agricultural tractor.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.599-602
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• 1997

Fluctuation of fungal zoospores on agar strips were observed in the rumen of sheep fed three different levels of dietary concentrate, timothy hay: concentrate = 3:0 (AF diet), timothy hay: concentrate = 2:1 (MC diet), timothy hay : concentrate = 1:2 (HC diet) respectively. The number of zoospores on the strip was drastically decreased after morning feed with AF diet. The number was the highest at 0 h ($1.34{\times}10^2/cm^2$), then declined to $2.0{\times}10^3/cm^2$ at 9 h after feeding. In the rumen of animals fed MC diet, the number of zoospores decreased with time after feeding, although the decrement was slower than that with AF diet. During 0-3 h after feeding, number of zoospores was $1.6{\times}10^4/cm^2$. Although the number slightly decreased at 6 and 9 h, relatively high levels were maintained. It seems that the inducers for zoospore-release were maintained at relatively high concentration throughout incubation period. The fluctuation pattern of number of germinated zoospores was different in the rumen of animals fed HC diet from those of AF and MC diets. The number of zoospores was constantly maintained at lower level ($1.0{\times}10^3/cm^2$) than the other diets. For MC diet, continuous high number of germinated zoospores may be due to the continuous release of zoospores by hemes in timothy hay and concentrate feed, and by unknown mechanisms. Unlike AF diet which promoted relatively rapid decline of zoosporogenesis, supplementation of concentrate feed to the timothy hay did not promote such rapid decline of zoosporogenesis. It was suggested that release of inducers for zoosporogenesis from concentrate feed persisted longer time than from timothy hay. HC diet promoted the lowest zoospore production, suggested the lowest fungal population size in this experiment. These results show that an appropriate amount of concentrate may support fungal growth and stimulate zoosporogenesis in the rumen.

• Journal of the Korean Society of School Health
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• v.5 no.2
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• pp.66-73
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• 1992

The objective of the study is to review the research materials for menarche including general characteristics of target population surveyed, mean age of subject, menarche experience rates of the subject and mean age at menarche, and to analyze secular trends of age at menarche in Korea from 1935 to 1992. The results of the study summarized as follows; 1. The range of age in the target pulation for menarcheal research was mainly 10-29 age groups, and most of them were middle, high school girls and college students. 2. There was positive relationship among mean age at menarche, level of menarche experiences rates and mean age of the subject(P<0.01). 3. In the relationship between the mean age at menarche and the level of menarche experience rate of the subject, the subject of study with higher menarche experience were more likely to be higher mean age at menarche than those with lower menarche experience rates. In case of menarcheal experience rates at 75-90 percent among the subject, the values of more and median were more close to the actual mean age at menarche under the assumption that all of the subject had experience menarche. 4. The trends of age at menarche during 1935-92 were linear decrement: Y = 85.93-0.036X in the whole country and Y = 91.35-0.039X in Seoul. The rates of secular diminution in age at menarche calculated to be about 4.3 months per decade in the nation-wide, and 4.6 months in Seoul during the periods. 5. To analyze the secular trends in menarcheal age, the researcher should set up criterians including the range of age in target population, the level of menarcheal experience rate and the regional characteristics.

• Korean Journal of Health Education and Promotion
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• v.15 no.2
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• pp.199-215
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• 1998

The health care environment exerts tremendous influence on community health practices. Here the author mention several major factors that will influence the future plan for health service and health education; that is, economic problem, the issues of decrement of infectious disease, increment of chronic degenerative disease due to natural increase of the elderly, increased frequency of traffic and industrial accidents and the issues of medical-technological advances etc. Therefore, special efforts by health personnel should be made to develop health education and health promotion strategies on a community-wide basis. Accordingly, the flexible accessibility, convenient availability, guaranteed medical service, sufficient supply of health information, and rapidly available medicaid service for special population such as the elderly, the handicapped, the disabled and the poor are considered. Also, the financial support from the central government and local self-government and active participation of health consumer to health service are needed in Korea, The role of the health personnel is to elicit, facilitate and maintain health promoting behavior with his and her assurance for health consumers being competent and supported in the voluntary choice of their health promoting activities. The health promoting activities such as the above mentioned will be produce escalation of their life Quality among Koreans.

• Tuberculosis and Respiratory Diseases
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• v.45 no.3
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• pp.495-502
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• 1998

Background: The prevalence of tuberculosis is closely related to socioeconomic status. Although the nation-wide prevalence of pulmonary tuberculosis was constantly decreasing during past 30years, there were few studies about prevalence of specific social groups in Korea. We examined prevalence of pulmonary tuberculosis among university freshmen, which might represent one of the specific social groups in Korea. Methods: The prevalence of radiologically active pulmonary tuberculosis among Seoul National University(SNU) freshmen was investigated from 1988 to 1997. And those results were compared with prevalence data of SNU freshmen from 1977 to 1987 and also with prevalence of age matched general population. Results: There was continuous decrement of prevalence of pulmonary tuBerculosis among university freshmen. In 1985 and 1990, there was significant prevalence difference between university freshmen and general population. But in 1995, the prevalence of both groups was not significantly different. Conclusion: The prevalence of pulmonary tuberculosis in university freshmen has decreased steadily. The prevalence of pulmonary tuberculosis in university freshmen was lower than that of age-matched general population during past 20years. However, this trend was not evident in 1995.