Theoretical study of the dechlorination reaction pathways of octachlorodibenzo-p-dioxin

The dechlorination reaction pathways of 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) by the hydrogen atom are investigated by the density-functional theory B3PW91 method. The dechlorination reactions have large exothermicity and small activation energies. The activation energies (approximately 5 kcal/mol) of the sigma-complex formation due to the hydrogen addition are lower than those (approximately 9 kcal/mol) of the direct chlorine abstraction. It is suggested that the sigma-complex plays an important role in the reactions, although it has scarcely been shown in previous studies of the dechlorination of dioxins. The sigma-complex formation is favored at low temperatures and the chlorine abstraction is favored at high temperatures. Furthermore, it is found that the lateral positions have a marginal preference over the longitudinal positions. The dechlorination of OCDD by the hydrogen atom is thus not likely to result in a dominant formation of the laterally substituted toxic congeners.     

Assessing the impact of the Japanese 2005 World Exposition Project on vascular plants' risk of extinction

The Red Data Book of Japanese Vascular Plants is based on their risk of extinction. In order to construct the list, 2000 taxa were evaluated using population data and rates of decline for approximately 4400 grids, each of approximately 100 km(2). This database can be used to estimate the impact of human activity on a threatened plant's risk of extinction. In order to evaluate extinction risks and apply the evaluation to conservation actions, the discount mean time to extinction is defined as a measure of extinction risk, where the present value of a species' persistence in the future decreases exponentially. The rate of decrease has to be much less than the rate of economic discounting, in order to realize intergenerational sustainability. Increases of the inverse, and logarithm, of the discount mean time to extinction are considered measures of the extinction risk. We applied these measures to an environmental impact assessment for the Japanese World Exposition that is to be held in 2005. Development will have a greater impact on threatened Salvia species than it will on star magnolia, Magnolia tomentosa, which has been conserved by changing the site plan.     

Postcopulatory mate guarding by vocalization in the Formosan squirrel

The Formosan squirrel, Callosciurus erythraeus thaiwanensis, emitted different vocalizations in response to terrestrial and aerial predators and snakes. Each vocalization caused nearby individuals to adopt a different type of anti-predator behaviour. In mating bouts, males produced two types of loud calls: precopulatory calls, emitted before copulations, and postcopulatory calls, emitted after copulations. The latter continued for 17 min on average. The estrous female and other males attending the mating bouts stopped moving during the postcopulatory call, so that the calling male was able to tend the female without interruption. The sound characteristics of anti-terrestrial-predator and postcopulatory calls recorded in the captivity were compared, and none of the ten characters of duration and frequency measured differed between the two calls. Playback experiments also showed that responses to the sounds in two different contexts, escape behaviour and defensive immobility, did not differ. The similarity between anti-predator and postcopulatory calls is discussed with reference to the possibility of manipulation and other explanatory hypotheses.     

Troop size,habitat quality,and home range area in Japanese macaques

Summary The correlation between troop size (N) and home range area (R) is examined in terms of habitat quality with 32 data sets for the Japanese macaque (Macaca fuscata) from its entire distribution range. The habitat quality is represented by the vegetation type and the degree the habitat is disturbed. A proportional relationship is found between N and R when the two major vegetation types (deciduous and evergreen) are discriminated and only the data from relatively undisturbed habitats are considered. This result is discussed in relation to bioenergetics.     

Food nitrogen footprint reductions related to a balanced Japanese diet

Dietary choices largely affect human-induced reactive nitrogen accumulation in the environment and resultant environmental problems. A nitrogen footprint (NF) is an indicator of how an individual’s consumption patterns impact nitrogen pollution. Here, we examined the impact of changes in the Japanese diet from 1961 to 2011 and the effect of alternative diets (the recommended protein diet, a pescetarian diet, a low-NF food diet, and a balanced Japanese diet) on the food NF. The annual per capita Japanese food NF has increased by 55% as a result of dietary changes since 1961. The 1975 Japanese diet, a balanced omnivorous diet that reportedly delays senescence, with a protein content similar to the current level, reduced the current food NF (15.2 kg N) to 12.6 kg N, which is comparable to the level in the recommended protein diet (12.3 kg N). These findings will help consumers make dietary choices to reduce their impacts on nitrogen pollution.     

Estrus cycle asynchrony in wild female chimpanzees, Pan troglodytes schweinfurthii

Although estrous synchrony has been reported in a number of mammalian species, most often among primates, methodological and analytical problems make it difficult to interpret these results. We developed a novel estrous synchrony index and employed a randomization procedure to analyze long-term observations of female chimpanzee (Pan troglodytes schweinfurthii) estrous cycles at the Mahale Mountains National Park, Tanzania. Our results revealed that female chimpanzees at Mahale avoid synchronizing their estrous periods with each other. We also found that birthrates decreased as the breeding sex ratio increased. We suggest that estrous asynchrony decreases female–female competition for mates. Asynchrony may also reduce the potential for male sexual coercion by nonpreferred mating partners.     

Environmental-economic models for total emission control of regional environmental pollution — input-output approach

This paper deals with a Leontief-type dynamic input-output analysis for total emission control of pollution. A dynamic input-output model can be described as a linear programming problem. In this paper an objective function to be minimized is chosen as the sum of pollutants emitted in a regional area throughout the planning period. It is assumed that consumption grows with a constant growth rate throughout the planning period. With this model, we can tell how to assign the elimination rate of pollutants to each production sector, under the constraint that the total emission standard is satisfied in each term of the planning period.