• Journal of the Korean Chemical Society
• /
• v.54 no.5
• /
• pp.633-642
• /
• 2010

In this study, science teachers' perception and attitude toward nanotechnology are examined through questionnaires gathered from 134 secondary science teachers. As a result, the study shows that science teachers have high perceptiveness. However, they do not understand specific information on nanotechnology correctly. Science teachers have positive attitudes toward nanotechnology and they have perceived risks of nanotechnology as well as benefits of nanotechnology. Science teachers show positive attitudes toward the application of nanotechnology, whereas they show negative attitudes toward personal information chip and nano-taste enhancer. Science teachers are exposed to nanotechnology via various sources such as TV and internet, whereas teachers rarely get information on nanotechnology-related concepts in textbooks and teaching resources. Science teachers have perceived many textbooks do not introduce enough nanotechnology-related concepts. Many teachers try to explain the nanotechnology when textbooks include nanotechnology-related concepts, whereas quite a few of teachers do not introduce the nanotechnology-related concepts in class.

• Journal of Veterinary Clinics
• /
• v.34 no.2
• /
• pp.82-86
• /
• 2017

We determined the risk factors for late embryonic mortality in dairy cows. We diagnosed pregnancy at 31 days and then confirmed the diagnosis at 45 days after artificial insemination (AI) via ultrasonography. The presence of an embryo with a heartbeat was the criterion for a positive pregnancy diagnosis. A diagnosis of late embryonic mortality was made when there was no positive sign of pregnancy in cows previously diagnosed as pregnant. The overall incidence of late embryonic mortality among 3,695 pregnancies was 6.9%. Logistic regression analysis revealed that herd size, AI month, synchronization protocol, and postpartum disease were important risk factors for late embryonic mortality. Herd size > 100 (odds ratio [OR]: 0.66, p < 0.05) and 50-100 lactating cows (OR: 0.63, p < 0.01) had lower risks of late embryonic mortality than herd size < 50 lactating cows. Cows inseminated during May-July had a higher risk (OR: 1.49, p < 0.05) of late embryonic mortality than cows inseminated during February-April. Cows inseminated after estrus following $PGF_{2{\alpha}}$ treatment also had a higher risk (OR: 1.77, p < 0.001) of late embryonic mortality than cows inseminated following natural estrus. Lastly, cows with postpartum disease tended to have a higher risk (OR: 1.26, p < 0.1) of late embryonic mortality than cows without postpartum disease. In conclusion, late embryonic mortality associated with the herd size, AI month, synchronization protocol, and postpartum disease in dairy cows.

• The Journal of the Korea Contents Association
• /
• v.21 no.9
• /
• pp.333-346
• /
• 2021

The purpose of this study is to examine the effects of digital cultural contents characteristics, perceived values and perceived risks on customer satisfaction and purchase intentions for Chinese consumers, and contribute to the development of digital cultural contents. In addition, a total of 328 valid samples were obtained through an online survey and empirical analysis was conducted. The analysis results of the study are as follows. First, except for creativity, which are characteristics of digital cultural contexts, entertainment and interactivity also have a significantly positive effect on both customer satisfaction and purchase intention. Second, perceived value has a significant positive effect on customer satisfaction and purchase intention, whereas perceived risk does not have this significant effect. Third, customer satisfaction has a partial mediating effect between the three factors(entertainment, interactivity, perceived value) and purchase intention. Therefore, to promote the development of digital cultural contents, we could promote consumers' purchase behavior by improving satisfaction through content entertainment, communication between content producers and service providers, and unity and value that customers actually feel during the consumption process.

• Journal of Preventive Medicine and Public Health
• /
• v.51 no.6
• /
• pp.265-274
• /
• 2018

Objectives: A positive association between air pollution and both the incidence and prevalence of diabetes mellitus (DM) has been reported in some epidemiologic and animal studies, but little research has evaluated the relationship between air pollution and diabetic coma. Diabetic coma is an acute complication of DM caused by diabetic ketoacidosis or hyperosmolar hyperglycemic state, which is characterized by extreme hyperglycemia accompanied by coma. We conducted a time-series study with a generalized additive model using a distributed-lag non-linear model to assess the association between ambient air pollution (particulate matter less than $10{\mu}m$ in aerodynamic diameter, nitrogen dioxide [$NO_2$], sulfur dioxide, carbon monoxide, and ozone) and emergency department (ED) visits for DM with coma in Seoul, Korea from 2005 to 2009. Methods: The ED data and medical records from the 3 years previous to each diabetic coma event were obtained from the Health Insurance Review and Assessment Service to examine the relationship with air pollutants. Results: Overall, the adjusted relative risks (RRs) for an interquartile range (IQR) increment of $NO_2$ was statistically significant at lag 1 (RR, 1.125; 95% confidence interval [CI], 1.039 to 1.219) in a single-lag model and both lag 0-1 (RR, 1.120; 95% CI, 1.028 to 1.219) and lag 0-3 (RR, 1.092; 95% CI, 1.005 to 1.186) in a cumulative-lag model. In a subgroup analysis, significant positive RRs were found for females for per-IQR increments of $NO_2$ at cumulative lag 0-3 (RR, 1.149; 95% CI, 1.022 to 1.291). Conclusions: The results of our study suggest that ambient air pollution, specifically $NO_2$, is associated with ED visits for diabetic coma.

• Journal of Korea Trade
• /
• v.23 no.7
• /
• pp.128-146
• /
• 2019

Purpose - The purpose of this paper is to investigate the relationship between internal control, economic policy uncertainty, and performance of cross-border merger and acquisition (M&A) based on the panel data of Chinese listed firms. The authors expected that internal control has a positive moderating effect on the performance of cross-border M&A and that it mainly occurs during periods when economic policies are relatively stable. In addition, the authors tried to find out the mechanism of internal control affecting cross-border M&A and the corporate performance. Design/methodology - The authors tested the hypotheses by a multivariate regression model based on the panel data of Chinese listed firms from 2009 to 2017. The dependent variable is the change value of business performance (DROA_1,2,3) and the explanatory variables are cross-border M&A (MA), China's uncertainty of economic policy (EPU), and internal control level (IC) respectively. Findings - The authors find that internal control has a positive moderating effect on the relationship between cross-border M&A and corporate performance. Further, the authors find that the moderating effect is more significant in state-owned enterprises and that it mainly occurs during periods when economic policies are relatively stable. Originality/value - This paper is the leading study that tries to analyze empirically the relationship between internal control, economic policy uncertainty, and performance of cross-border M&A. It provides a new avenue through which internal control might reasonably mitigate the risks of cross-border M&A and correspondingly improve the performance of cross-border M&A. It also confirms the moderating effect of internal control on the performance of cross-border M&A under the uncertainty of economic policy.

• Annals of Occupational and Environmental Medicine
• /
• v.34
• /
• pp.5.1-5.10
• /
• 2022

Background: Some epidemiological studies have estimated exposure among flight attendants with and without breast cancer. However, it is difficult to find a quantitative evaluation of occupational exposure factors related to cancer development individually in the case of breast cancer in flight attendants. That is, most, if not all, epidemiological studies of breast cancer in flight attendants with quantitative exposure estimates have estimated exposure in the absence of individual flight history data. Case presentation: A 41-year-old woman visited the hospital due to a left breast mass after a regular check-up. Breast cancer was suspected on ultrasonography. Following core biopsy, she underwent various imaging modalities. She was diagnosed invasive ductal carcinoma of no special type (estrogen receptor positive in 90%, progesterone receptor positive in 3%, human epidermal growth factor receptor 2/neu equivocal) with histologic grade 3 and nuclear grade 3 in the left breast. Neoadjuvant chemotherapy was administered to reduce the tumor size before surgery. However, due to serious chemotherapy side effects, the patient opted for alternative and integrative therapies. She joined the airline in January, 1996. Out of all flights, international flights and night flights accounted for 94.9% and 26.2, respectively. Night flights were conducted at least four times per month. Moreover, based on the virtual computer program CARI-6M, the estimated dose of cosmic radiation exposure was 78.81 mSv. There were no other personal triggers or family history of breast cancer. Conclusions: This case report shows that the potentially causal relationship between occupational harmful factors and the incidence of breast cancer may become more pronounced when night shift workers who work continuously are exposed to cosmic ionizing radiation. Therefore, close attention and efforts are needed to adjust night shift work schedules and regulate cosmic ionizing radiation exposure.

• The Journal of Asian Finance, Economics and Business
• /
• v.6 no.3
• /
• pp.19-26
• /
• 2019

The paper aims to measure stock price volatility on Ho Chi Minh stock exchange (HSX). We apply symmetric models (GARCH, GARCH-M) and asymmetry (EGARCH and TGARCH) to measure stock price volatility on HSX. We used time series data including the daily closed price of VN-Index during 1/03/2001-1/03/2019 with 4375 observations. The results show that GARCH (1,1) and EGARCH (1,1) models are the most suitable models to measure both symmetry and asymmetry volatility level of VN-Index. The study also provides evidence for the existence of asymmetric effects (leverage) through the parameters of TGARCH model (1,1), showing that positive shocks have a significant effect on the conditional variance (volatility). This result implies that the volatility of stock returns has a big impact on future market movements under the impact of shocks, while asymmetric volatility increase market risk, thus increase the attractiveness of the stock market. The research results are useful reference information to help investors in forecasting the expected profit rate of the HSX, and also the risks along with market fluctuations in order to take appropriate adjust to the portfolios. From this study's results, we can see risk prediction models such as GARCH can be better used in risk forecasting especially.

• Journal of Preventive Medicine and Public Health
• /
• v.30 no.1 s.56
• /
• pp.145-155
• /
• 1997

Interview survey and dermatological examination have been performed to investigate the health problems of workers continuously exposed to coal-tar pitch. The phototoxicity of coal-tar pitch was confirmed by the photopatch tests for six healthy adults. The main results are followings; 1. There was no special history of allergic diseases in both the exposed and non-exposed group. 2. The frequency of the phototoxic dermatosis and the coal-tar acne in the exposed group was significantly greate.(p<0.05) than that of the control group. In the exposed group, the phototoxic dermatosis and the coal-tar acne were observed in nine workers(90%) and seven workers(70%), respectively. However, those, disease were not observed in the control group. 3. Five results(83%) were positive to the photopatch test for coal-ta. pitch 48 hours after UVA irradiation. But the lesion was subsiding 72 hours after UVA irradiation. 4. Malignant cancers were not reported among workers ever exposed to coal-tar pitch. In conclusion, it appears that workers exposed to coal-tar pitch have high risks of phototoxic dermatosis and coal-tar acne. A health policy should be provided to prevent phototoxic dermatosis among coal-tar pitch workers. More studies are required to determine malignancy.

• Journal of Chest Surgery
• /
• v.28 no.5
• /
• pp.464-470
• /
• 1995

From Jan 1988 to Dec 1993, 196 consecutive patients with various pulmonary diseases underwent pneumonectomy. Mean age was 54.0 years[range:7-74 . The underlying diseases were lung cancer[154 cases , destroyed lung[29 cases with pulmonary tuberculosis or empyema thoracis and others[13 cases . The overall mortality and complication rate were 5.6% and 14.8%. In the groups of more than and less than 60 years of age, there was significant differences in mortality rate[P=0.004 . In the group of pneumonectomy and pleuropneumonectomy, there was no significant differences in mortality[P=0.164 and complication rate[P=0.052 . In the group of normal and abnormal EKG, there was no significant differences in mortality[P=0.560 and complication rate[P=0.693 . In the preoperative FEV1, preoperative FVC and predicted postoperative FEV1, prognostic cut-off points were 1800cc, 2600cc and 1300cc, and at points, positive predicted value were 12.3%, 10.5%.and 7.7% and negative predicted value were 97.8%, 98.3% and 96.2% respectively. The preoperative FEV1 is the most reliable indicator in assessment of prognosis of pneumonectomy.

• Nutrition Research and Practice
• /
• v.3 no.2
• /
• pp.162-166
• /
• 2009

The objectives of this study were to identify the dietary patterns associated with hypertension among Korean males. Data from the 2001 Korean National Health and Nutrition Survey of 1,869 men aged 20-65 years were used for the analysis. As an initial analysis, a factor analysis was applied to identify major dietary patterns among the subjects. Then logistic regression analysis was conducted to identify the pattern related with hypertension. As a result of the initial analysis, three major dietary patterns were identified. Dietary pattern 1 (traditional) was heavily loaded with vegetables, fish and cereal. Dietary pattern 2 (Western) was loaded with fast foods, bread, meats and dairy products. Dietary pattern 3 (Drinker) was loaded with mostly pork, beer and soju (Korean liquor). From the second stage of the analysis, there was a tendency of positive association between traditional patterns and hypertension risks. However, the tendency did not meet statistical significance level (p<0.05). In summary, unlikely findings from European and American studies, vegetables rich traditional dietary patterns did not show any protective effect on hypertension in Korean males. The Korean dietary practice, which is consuming salted vegetables instead of fresh vegetables, might have played a role in these findings. However, the full explanation of the findings remained to be answered with further investigation since none of the dietary patterns identified showed any statistical significance.