A Novel Methodology to Evaluate Health Impacts Caused by VOC Exposures Using Real-Time VOC and Holter Monitors

While various volatile organic compounds (VOCs) are known to show neurotoxic effects, the detailed mechanisms of the action of VOCs on the autonomic nervous system are not fully understood, partially because objective and quantitative measures to indicate neural abnormalities are still under development. Nevertheless, heart rate variability (HRV) has been recently proposed as an indicative measure of the autonomic effects. In this study, we used HRV as an indicative measure of the autonomic effrects to relate their values to the personal concentrations of VOCs measured by a real-time VOC monitor. The measurements were conducted for 24 hours on seven healthy subjects under usual daily life conditions. The results showed HF powers were significantly decreased for six subjects when the changes of total volatile organic compound (TVOC) concentrations were large, indicating a suppression of parasympathetic nervous activity induced by the exposure to VOCs. The present study indicated these real-time monitoring was useful to characterize the trends of VOC exposures and their effects on autonomic nervous system

OMAE2003-37305 Case Study on the Universal Town Planning for Water Front Redevelopment in Okinawa Prefecture

Abstract In Japan, recently, the word 'Universal Design' is getting to settle down in the field of town planning and producing subsistence goods owing to the prospects of coming super-aged society

Influence of Topographic Conditions on Teak Growth Performance in Mountainous Landscapes of Lao PDR

Teak is a globally valuable hardwood tree species, as its growth performance is important for timber productivity. The purpose of this study was to establish an effective management system for teak plantations in the Lao PDR. Using diameter at breast height (DBH) and height growth as significant indicators of growth performance, we investigated the relationship between tree growth curve parameters of teak and topographic conditions. Stem analysis data for 81 sample trees (three trees selected in canopy trees with predominant height in each plot) were examined for growth performance using the Mitscherlich growth function. The results of Spearman’s partial rank correlation indicated that the upper limits of DBH and tree height growth had significant negative correlations with the slope gradient and stand density. The curvature of DBH and tree height growth curves showed significant positive correlations with the slope form. Moreover, the elevation and slope gradient showed significant negative correlations with the curvature of tree height growth curve. However, the time lag of DBH growth showed a significant negative correlation with the slope position, while the slope gradient was positively correlated with the time lag of tree height growth. These results suggest that teak planted at lower slopes has faster growth rates and that there is an interaction with the gentle concave slope of this area

Influence of Topographic Conditions on Teak Growth Performance in Mountainous Landscapes of Lao PDR

Teak is a globally valuable hardwood tree species, as its growth performance is important for timber productivity. The purpose of this study was to establish an effective management system for teak plantations in the Lao PDR. Using diameter at breast height (DBH) and height growth as significant indicators of growth performance, we investigated the relationship between tree growth curve parameters of teak and topographic conditions. Stem analysis data for 81 sample trees (three trees selected in canopy trees with predominant height in each plot) were examined for growth performance using the Mitscherlich growth function. The results of Spearman’s partial rank correlation indicated that the upper limits of DBH and tree height growth had significant negative correlations with the slope gradient and stand density. The curvature of DBH and tree height growth curves showed significant positive correlations with the slope form. Moreover, the elevation and slope gradient showed significant negative correlations with the curvature of tree height growth curve. However, the time lag of DBH growth showed a significant negative correlation with the slope position, while the slope gradient was positively correlated with the time lag of tree height growth. These results suggest that teak planted at lower slopes has faster growth rates and that there is an interaction with the gentle concave slope of this area

Correlations among Tree Quality, Stand Characteristics, and Site Characteristics in Plantation Teak in Mountainous Areas of Lao PDR

Teak (Tectona grandis Linn. f) is a globally valuable hardwood tree species whose growth performance and tree quality characteristics are controlled by various factors. Teak tree quality characteristics such as stem straightness, buttressing, and protuberant buds/knots are important in the sawing process, and directly affect timber yield, timber grade, recovery, and cost. In this study, we assessed the relationships among tree quality characteristics, stand characteristics, and site characteristics in plantation teak in the Luang Prabang province of the Lao PDR. We established 53 sample plots (20 × 20 m) and measured a total of 2149 sample trees. The stand-level tree age ranged from 10 to 31 years, and the trees were distributed in various modes of topography. The altitude ranged from 287 to 867 masl. The results of Spearman’s partial rank correlation analysis among the parameters revealed the present condition of the teak plantation forest in the region. The altitude was related to stand age and was correlated with tree quality characteristics such as epicormic shoots, mode of branching, and branch size. The correlation results suggest that higher-density plantation at the higher altitude sites might be suitable for teak plantations in this area. In addition, we found that a longer rotation in forest management might degrade tree quality