• Journal of Labour Economics
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• v.34 no.1
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• pp.1-32
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• 2011

This paper explores the effect of relative age at elementary school entry, which is determined by birth date and school entrance law, on college entrance. First, I compare the college entrance rate between students born in January or February and those born in other months. Second, I estimate the effect of age at school entry on college entrance. Relatively older students at school entry are likely to have better educational outcomes during the first college entrance. However, these differences in educational outcomes seem to decrease the more that younger students repeat taking the college entrance exam.

• The Korean Journal of Pain
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• v.23 no.1
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• pp.11-17
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• 2010

Background: The target of lumbar sympathetic ganglion block is the anterolateral surface of the L2, 3 and 4 vertebral bodies, where the lumbar sympathetic ganglion usually lies. In most cases, a block-needle is inserted approximately 5-8 cm lateral to spinous process on the skin and directed to the anterolateral surface of vertebral body obliquely. The purpose of this study is to determine the safe entry angle and entry point in Korean by using the abdominal CT scan images. Methods: The abdominal CT images of eighty five patients were recruited to this study. The minimal angle aimed at the lumbar sympathetic ganglion that can pass through the lateral aspect of body and maximal angle that avoids puncturing the kidney, ureter or retroperitoneal space were measured. The distance from midline to skin entry point was also measured. Results: There was no significant difference in entry angle among L2, 3, and 4 level. The entry angle was similar in the right and left side, and in males and females. The entry angle of old age group was significantly smaller than that of young age group. The calculated safe entry angle was $30.5{\pm}0.4^{\circ}$ and entry point was $7.7{\pm}0.2\;cm$ and $6.7{\pm}0.1\;cm$ lateral from midline in males and females respectively. Conclusions: These measurements can be used as a reference for lumbar sympathetic ganglion block and radiofrequency lesioning. Prior to performing the lumbar sympathetic ganglion block for cancer patients, the abdominal CT scan should be reviewed to prevent complications.

• Journal of Labour Economics
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• v.41 no.2
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• pp.89-106
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• 2018

As the Korean school entry date changed in 2010, from March 1 to January 1, January-born children are older than their peers at school, and December-born children are the youngest. This implies that parents may have incentives to avoid giving birth in December, and a mother who gives birth in this month is likely to be a mother who is not very concerned with her child's education. This study finds that the mothers of December-born children are younger, have lower education level, and have a lower probability of being employed than other mothers. This means that December-born children are more disadvantaged because they are the youngest among their peers and are from families of low socioeconomic backgrounds.

• Journal of Families and Better Life
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• v.34 no.4
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• pp.1-19
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• 2016

The present study aimed at investigating the relations between the amount of child care experienced in the first three years of life and socioemotional development of children at age 4 indicated by problem behaviors and peer competence. Using the longitudinal data of the Panel Study of Korean Children(PSKC), the information of 1,699 children were analyzed. The results indicated that any child care experience, hours in child care, full-time child care and early entry to child care were significantly related to children's externalizing behavior problem and play disruption at age 4. Some significant relations were detected between child care experience and better peer competence as well. Interestingly, the patterns of relations were different for boys and girls. Being in child care, a greater amount of child care and early entry to child care tended to be related to externalizing problem behaviors of boys and whereas they were more related to peer competence of girls indicated by play interaction, play disruption and play disconnection. Child care hours at age 3 were relative stronger predictors of children's development compared to those at age 1 or at age 2. The findings imply that the amount of child care during the first 3 years of life does not have strong harmful effects on preschoolers' socioemotional development and that there are differences in the effects of child care on boys and girls.

• The Journal of Industrial Distribution & Business
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• v.9 no.7
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• pp.43-52
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• 2018

Purpose - The main purpose of this paper is to examine the effect of children's age on maternal labor supply in Korea using survival analysis. Specifically, we focus on the career re-interruption of women having children under age 12, which has rarely been studied in the existing literature. Research design, data, and methodology - We use micro data from the Korea Labor and Income Panel Study (KLIPS) surveyed from 1998 to 2016. Instead of using a pre-school child dummy or the number of young children as an explanatory variable, 9 children's age dummies are included to capture the effect of nurturing 0 to 9 years old children. This study estimates the hazard of a woman's exiting the labor market after her first experience of the career interruption, rather than the hazard of the first career interruption itself. A Cox proportional hazard model is applied to numerically capture the impact of children's age on behavioral changes in maternal labor supply. The sample used in this analysis is women between 15 and 54 years old. Most of all, we restrict the sample to women who had at least a child between 0 and 12 years old at the time of quitting their jobs. Results - The Cox proportional hazard model estimates show a strong negative effect of a 0-year-old child on maternal labor supply. Mothers with newborns have a high hazard ratio of labor force exit after the re-entry. The hazard of women with infants is three times higher than those with children aged 10 to 18. Additionally, the results show that not only newborns, but also children in the age of school-entry have a negative impact on their mother's labor supply. Conclusions - The findings reveal that children's ages need to be properly expanded and included when analyzing the effect of children and their ages on married women's labor supply, especially on women's career re-interruption. A large negative effect of 7-year-old children on maternal labor supply found here indicates that supporting mothers with school age children as well as pre-school children is necessary to prevent mothers from leaving the labor market.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.1
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• pp.41-46
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• 2014

Purpose: The spontaneous seroconversion rate of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) virus infection in children is lower than that in adults. However, few studies have investigated the rate of transition from the immune-tolerant to the early immune-clearance phase in children. Methods: From February 2000 to August 2011, we enrolled 133 children aged <18 years who had visited the Department of Pediatrics, Kyungpook National University Hospital. All subjects were in the immune-tolerant phase of HBeAg-positive CHB virus infection. The estimated transition rate into the early immune-clearance phase was calculated using the Kaplan-Meier method. Results: Among the 133 enrolled pediatric CHB virus infection patients in the HBeAg-positive immune-tolerant phase, only 21 children (15.8%) had converted to the early immune-clearance phase. The average age at entry into active hepatitis was $10.6{\pm}4.8$ years. The incidence of transition from the immune-tolerant to the early immune-clearance phase in these children was 1.7 episodes/100 patient-years. When analyzed by age, the estimated transition rate was 4.6%, 7.1%, and 28.0% for patients aged <6, 6-12, >12 years, respectively. Conclusion: In children with CHB virus infection, the estimated rate of entry into the early immune-clearance phase was 28.0% for patients aged 12-18 years, which was significantly higher than that observed for children aged <12 years (11.7%; p=0.001).

• Safety and Health at Work
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• v.12 no.1
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• pp.35-41
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• 2021

Introduction: Training standards for long-haul truck drivers (LHTD) are rapidly evolving in Canada, yet the opinions of the drivers themselves have not been adequately considered. The purpose was to survey LHTD on their work training history and to examine LHTD perceptions of driver training and licensing protocols. Methods: LHTD were recruited across two Western Canadian provinces from seven different truck stops. The sample completed 207 surveys and 67 semi-structured interviews. Results: The average age of the participants was 52.5 ± 11.5 years (range 24-79); 96% were men. Approximately 33% of the LHTD had at least one crash. Those who did not receive formal driver training were significantly more likely to crash than those who had received training. Participants stated that current training standards are inadequate for the industry, particularly for new drivers. According to participants, entry-level curriculums should consist of both classroom and practical training, as well as on-road observation with a senior mentor. LHTD reported that many new drivers are not equipped to drive in various contexts and settings (e.g., mountains, slippery roads). Conclusions: LHTD are not confident in the current training guidelines for novice truck drivers. Revisions to the training curriculum and standardization across Canada should be considered. Practical Application: A federal mandatory entry-level training program is needed in Canada to ensure that all new LHTD ascertain the necessary skills to drive safely. Such a program requires government involvement and input from LHTD to facilitate appropriate licensure and consistent training for all drivers.

• Journal of Korean Neurosurgical Society
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• v.47 no.4
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• pp.271-277
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• 2010

Objective : The purpose of this study is to evaluate the clinical characteristics and surgical outcome of cerebellopontine angle (CPA) epidermoids presenting with trigeminal neuralgia. Methods : Between 1996 and 2004, 10 patients with typical symptoms of trigeminal neuralgia were found to have cerebellopontine angle epidermoids and treated surgically at our hospital. We retrospectively analyzed the clinico-radiological records of the patients. Results : Total resection was done in 6 patients (60%). Surgical removal of tumor and microvascular decompression of the trigeminal nerve were performed simultaneously in one case. One patient died due to postoperative aseptic meningitis. The others showed total relief from pain. During follow-up, no patients experienced recurrence of their trigeminal neuralgia (TN). Conclusion : The clinical features of TN from CPA epidermoids are characterized by symptom onset at a younger age compared to TN from vascular causes. In addition to removal of the tumor, the possibility of vascular compression at the root entry zone of the trigeminal nerve should be kept in mind. If it exists, a microvascular decompression (MVD) should be performed. Recurrence of tumor is rare in both total and subtotal removal cases, but long-term follow-up is required.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4667-4669
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• 2013

We evaluated cigarette smoking as a risk factor for prostate cancer in a prospective, population-based cohort study. The subjects were 14,450 males among the participants in the Seoul Male Cancer Cohort Study who had at least 1-year follow-up. They were followed up between 1993 and 2008. During the 16-year follow-up period, 87 cases of prostate cancer occurred over the 207,326 person-years of the study. The age-adjusted relative risks of past and current smokers at entry were 0.60 (95%CI: 0.34-1.06) and 0.70 (95%CI: 0.43-1.13), respectively, suggesting that cigarette smoking may not be a risk factor for prostate cancer. The relationship between prostate cancer and other modifiable factors, such as Westernized diet, should be studied with the goal of establishing prevention programs for prostate cancer.

• Journal of Korean Neurosurgical Society
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• v.44 no.4
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• pp.185-189
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• 2008

Objective : The authors present their experiences with stereotactic multiplanar reformatted (MPR) computed tomography (CT)-guided catheter placement for thrombolysis of spontaneous intracerebral hematoma (sICH) and their clinical results. Methods : In 23 patients with sICH, MPR CT-guided catheter placement was used to select the trajectory and target point of hematoma drainage. This group was comprised of 11 men and 12 women, and the mean age was 57.5 years (range, 31-79 years). The patients' initial Glasgow Coma Scale scores ranged from 7 to 15 with a median of 11. The volume of the hematoma ranged from 24 mL to 86 mL (mean 44.5 mL). A trajectory along the main axis of the hematoma was considered to be optimal for thrombolytic therapy. The trajectory was calculated from the point of entry through the target point of the hematoma using reformatted images. Results : The hematoma catheter was left in place for a median duration of 48.9 hours (range 34 to 62 hours). In an average of two days, the average residual hematoma volume was 6.2 mL (range 1.4 mL to 10.2 mL) and was reduced by an average of 84.7% (range 71.6% to 96.3%). The residual hematoma at postoperative seven days was less than 5 mL in all patients. There was no treatment-related death during hospitalization. Conclusion : The present study indicates that stereotactic MPR CT-guided catheter placement for thrombolysis is an accurate and safe procedure. We suggest that this procedure for stereotactic removal of sICH should be considered for the optimization of the trajectory selection in the future.