A Performance Comparison of Various Bootstrap Methods for Diffusion Processes

In this paper, we compare the finite sample performances of various bootstrap methods for diffusion processes. Though diffusion processes are widely used to analyze stocks, bonds, and many other financial derivatives, they are known to heavily suffer from size distortions of hypothesis tests. While there are many bootstrap methods applicable to diffusion models to reduce such size distortions, their finite sample performances are yet to be investigated. We perform a Monte Carlo simulation comparing the finite sample properties, and our results show that the strong Taylor approximation method produces the best performance, followed by the Hermite expansion method

Associations Between Conventional Healthy Behaviors and Social Distancing During the COVID-19 Pandemic: Evidence From the 2020 Community Health Survey in Korea

Objectives: Many studies have shown that social distancing, as a non-pharmaceutical intervention (NPI) that is one of the various measures against coronavirus disease 2019 (COVID-19), is an effective preventive measure to suppress the spread of infectious diseases. This study explored the relationships between traditional health-related behaviors in Korea and social distancing practices during the COVID-19 pandemic. Methods: Data were obtained from the 2020 Community Health Survey conducted by the Korea Disease Control and Prevention Agency (n=98 149). The dependent variable was the degree of social distancing practice to cope with the COVID-19 epidemic. Independent variables included health-risk behaviors and health-promoting behaviors. The moderators were vaccination and unmet medical needs. Predictors affecting the practice of social distancing were identified through hierarchical multiple logistic regression analysis. Results: Smokers (adjusted odds ratio [aOR], 0.924) and frequent drinkers (aOR, 0.933) were more likely not to practice social distancing. A greater degree of physical activity was associated with a higher likelihood of practicing social distancing (aOR, 1.029). People who were vaccinated against influenza were more likely to practice social distancing than those who were not (aOR, 1.150). However, people with unmet medical needs were less likely to practice social distancing than those who did not experience unmet medical needs (aOR, 0.757). Conclusions: Social distancing practices were related to traditional health behaviors such as smoking, drinking, and physical activity. Their patterns showed a clustering effect of health inequality. Therefore, when establishing a strategy to strengthen social distancing, a strategy to protect the vulnerable should be considered concomitantly

Effects of Maternal Decisional Authority and Media Use on Vaccination for Children in Asian Countries.

Background and objectives: It is now accepted that vaccination is a critical public health strategy in preventing child morbidity and mortality. Understanding factors that promote vaccination is a critical first step. The objective of this study was to investigated associations of maternal decisional authority and media use on vaccination for children in six South and Southeast Asian countries. Materials and Methods: Data come from demographic and health surveys conducted in Bangladesh, Cambodia, Indonesia, Nepal, Pakistan, and the Philippines between 2011 and 2014 (N = 45,168 women). Main outcome variables were four types of basic vaccination for children. Independent variables were maternal decisional authority and media use. Hierarchical multivariable regression analyses were performed to examine associations. Results: Children of mothers who had more decisional authority were more likely to be vaccinated compared to those participants who did not have such authority. The likelihood to have their children vaccinated was higher among women who frequently used media than those who did not use media. Conclusions: Maternal decisional authority and media use are related to improved vaccination for children. To increase vaccination rates in developing countries in South and Southeast Asia, programs and policies that promote maternal decisional authority and the use of media for health need to be implemented to help families and local communities

Impact of placement of fitbit HR under laboratory and free-living conditions

© 2020 by the authors. Wrist-worn activity monitors have become accessible for measuring physical activities, but an activity monitor\u27s accuracy worn at different placements is not well understood. This study aimed to examine the differences in measurements of heart rates, step counts, and calories estimated from the fitness tracker worn at different locations and the accuracy of Fitbit HR against criterion measures. Thirty-two healthy adults participated in this study. Participants wore Fitbit HR at four different locations (right proximal, distal, and left proximal, distal). Treadmill exercise consisted of five 5-min phases including slow walking and jogging. Free-living activities involved ten 5-min activities with four different intensities. We found that the placement of Fitbit HR has no significant influence on the measurement outcomes overall. However, significant differences were observed in the step counts between left and right while climbing stairs (p = 0.003) and sports activities (p \u3c 0.001). The accuracy of Fitbit HR measurements against the criterion measure was moderate. However, we found out that Fitbit HR overestimated the calories regardless of their positions and activity types. In conclusion, the different placements of Fitbit HR do not have a significant influence on the measurements and Fitbit HR was moderately associated with criterion reference devices for measures of heart rate and steps

The Acute and Chronic Effect of Korea Ginseng Supplement on Exercise Performance, Cognitive Function, and Fatigue Recovery

The purpose of this study was to determine the acute and chronic effects of Korean ginseng supplements on exercise performance, cognitive function, and fatigue recovery. The study used double-blind, placebo-controlled, crossover design. Twelve healthy adult males (age = 31 ± 6.86 yrs) were randomly assigned to either KGD or placebo trials. All subjects conducted the exercise consisted with 30 minutes cycling at 70-75% of VO2 max followed by 16 km time trial with 30 minutes resting periods. All subjects were tested for muscular power, strength, endurance, cognitive function, and fatigue. The subjects took KGD (280 ml containing 5.88 mg of ginsenosides) or placebo 90 mins before exercise trials and following 7 days. The blood sample was drawn for IL-6, myoglobin, and total antioxidant capacity immediately after time trial, as well as 2, 24, 48, and 72 hours. After 2 weeks of wash-out period, the subjects were crossed over into the opposite trial and performed the same test. Repeated measures ANOVAs were used to examine the effect of acute and chronic intake of ginseng on exercise performance and blood variables. An alpha of .05 was used, and the Greenhouse-Geisser (G-G) adjusted F and degrees of freedom were reported. In a placebo trial, peak power and mean power levels were significantly decreased across time, F (1.47, 13.24) = 4.63, G-G p = .039, h2p = .340 and F (1.46, 13.13) = 5.31, G-G p = .028, h2p = .371 while no differences were found in a ginseng trial. In a placebo trial, average reaction time (ART) was significantly increased across time, F (1.29, 11.63) = 10.81, G-G p = .005, h2p = .546, but in a ginseng trial, no difference in ART was found across time, F (1.54, 13.86) = 4.02, G-G p = .051, h2p = .309. There was a significant increase in TAC across time in a ginseng trial, F (1.42, 11.37) = 5.07, G-G p = .035, h2p = .388 while no difference was found in a placebo trial. No significant differences were found in other variables from placebo and ginseng trails. The 7 days of KRG supplementation significantly reduced the serum myoglobin concentration across time in the KGD trial, F (1.88, 13.17) = 5.18, G-G p = .023, while no difference was found in the placebo trial, F (2.21, 17.66) = .88, G-G p = .443. No significant differences were observed in serum total antioxidant activity and IL-6 between KGD and placebo trials. The study shows that Korean ginseng supplement before stating the exercise improve anaerobic capacity, cognitive function in particular psychomotor vigilance task, and fatigue recovery during cycling exercise. And 7 days of Korean ginseng supplement reduces muscle damage and fatigue after cycling exercise