A spatially explicit empirical model of structural development processes in natural forests based on climate and topography

Stand structure develops with stand age. Old-growth forests with well-developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old-growth index as functions of climatic and topographic covariates. We used a hierarchical Bayesian method for analysis of extensive snap-shot National Forest Inventory (NFI) data in Japan (n = 9244) to account for differences in stand age. Development rates of structural variables and the old-growth index exhibited curvilinear responses to environmental covariates. Flat sites were characterized by high rates of structural development. Approximately 150 years were generally required to attain high values (approximately 0.8) of the old-growth index. However, the predicted age to achieve specific values varied depending on environmental conditions. Spatial predictions highlighted regional variation in potential structural development rates. For example, sometimes there were differences of >100 years among sites, even in the same catchment, in attainment of a medium index value (0.5) after timber harvesting. The NFI data suggested that natural forests, especially old natural forests (>150 years), remain generally on unproductive ridges, steep slopes, or areas with low temperature and deep snow, where many structural variables show slow development rates. We suggest that maintenance and restoration of old natural forests on flat sites should be prioritized for conservation due to the likely rapid development of stand structure, although remaining natural forests on low-productivity sites are still important and should be protected.     

PCDDs & PCDFs from the MSW incinerator

In the range 670 to 900°C furnace temperature, dioxin concentrations strongly depended upon the oxygen concentration in the flue gas. In keeping the oxygen concentration at apploximately 12 percent, dioxin was reduced in the flue gas. For further dioxin reduction from the flue gas, it was the most effective process to treat the flue gas with bag filter system with 120 C operation.     

Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.Electronic supplementary material  Supplementary material is available for this article at and is accessible for authorized users.     

Ambiguities inherent in sums-of-squares-based error statistics

Commonly used sums-of-squares-based error or deviation statistics—like the standard deviation, the standard error, the coefficient of variation, and the root-mean-square error—often are misleading indicators of average error or variability. Sums-of-squares-based statistics are functions of at least two dissimilar patterns that occur within data. Both the mean of a set of error or deviation magnitudes (the average of their absolute values) and their variability influence the value of a sum-of-squares-based error measure, which confounds clear assessment of its meaning. Interpretation problems arise, according to Paul Mielke, because sums-of-squares-based statistics do not satisfy the triangle inequality. We illustrate the difficulties in interpreting and comparing these statistics using hypothetical data, and recommend the use of alternate statistics that are based on sums of error or deviation magnitudes.     

Fine structure of the “button setae” in the deep-sea pelagic copepods of the genus Euaugaptilus (Calanoida: Augaptilidae)

 Many species of the carnivorous copepod family Augaptilidae, a primarily meso- and bathypelagic group, possess specialized “buttons” on the setae of their maxilla and maxilliped, which have been thought to be a simple cuticular outgrowth. The fine structure of the button setae in three species of Euaugaptilus was examined by light- and electron microscopy from samples collected in the eastern Indian Ocean and the subtropical western North Pacific. The buttons are arranged in two rows along the inner surface of the setae. There are differences in the shape, size, and arrangement of buttons among the three species, Euaugaptiluslaticeps, E.longimanus, and E.magnus. The button setae have an elaborate internal structure consisting of “setal shaft”, “stalk”, “disc”, and “outer membrane”, with microtubule bundles in the setal lumen, but have no muscular tissues. The disc has only pin-point contact to the core of the stalk, but has connection over a wider area with the fibrous tissue surrounding the core, and the contact area between the stalk and the setal shaft is also small. These structures suggest that the disc will move freely on the apex of the core of the stalk and the stalk may be movable at its connection to the setal shaft. All these components of the button setae may function in concert to fit the surface of the discs firmly to the surface of a prey, and to absorb the energy generated by the struggling prey. Received: 30 November 1999 / Accepted: 19 May 2000     

Direct observation of microcirculatory parameters in rat brain after local exposure to radio-frequency electromagnetic field

A cranial window method modified for our experiment enabled to observe the cerebral microcirculation including the blood-brain barrier permeability after a local expose to radio-frequency electromagnetic fields with a monopole antenna in rats. The present report reviews our recent publications that reported no noticeable changes in the cerebral microcirculatory parameters due to RF-EMF exposure.     

Dioxins in human milk and smoking of mothers

BACKGROUND: The relation between the levels of dioxins in human breast milk and the smoking habits of the mothers is controversial. To clarify this relationship, we analyzed data from the human milk survey in Japan. METHODS: The human milk survey has been conducted in Japan since 1997. Healthy pregnant women aged 20-39 years were recruited and 50 ml of breast milk was collected from them at 30 days after delivery. PCDDs, PCDFs, and dioxin-like PCBs were measured by using GC/MS. The smoking habits of the mothers were established by interviewing them soon after delivery and were classified into four categories: current smokers, ever smokers who quit smoking at the pregnancy, ever smokers who quit smoking before the pregnancy, and never smokers. The levels of dioxins in breast milk were compared in the four categories of smoking among 853 primiparas. In addition, we analyzed the association between dioxin levels and passive smoking among never smokers. The geometric means of the dioxin concentrations were calculated in order to compare the differences between dioxins. RESULTS: The geometric means of dioxin-like PCBs in milk of never smokers was the highest (9.2 pg TEQ/g fat); followed by ever smokers who quit smoking before the pregnancy, ever smokers who quit smoking at the pregnancy, and current smokers (7.5, 7.2, and 6.6 pg TEQ/g fat, respectively). The differences between these levels were statistically significant (ANOVA, p<0.001). No significant difference was observed between the level of dioxins in milk from never smokers subjected to passive smoking status and those who had not experienced passive smoking. CONCLUSION: The levels of dioxin-like PCBs in human milk were negatively related to the smoking habits of mothers.     

Maturity classification and group maturity of the red sea bream Pagrus major

The criteria of ovarian maturity during the spawning season and maturity rates according to age are described for the female red sea bream Pagrus major collected from the Chikuzenkai between April and June, 1984. The degree of maturity of the ovary is categorized into four stages based on the maturation stage of the most advanced oocytes in the ovary, rate of atresia and occurrence of post-ovulatory follicles. The ovarian maturity rates in fish aged 2, 3, 4 and 5 years were shown to be 5.8, 46.2, 75.0 and 97.3%, respectively, assuming that yolked ovaries with low levels of atresia (<50% yolked oocytes affected) attain maturity. The fork length at which 50% of the fish attained maturity ranged from 280 to 300 mm.     

Methane recovery from acidic tofu wastewater using an anaerobic fixed-bed reactor with bamboo as the biofilm carrier

Journal of Material Cycles and Waste Management - Wastewater generated during acid coagulation in tofu processing has high organic concentrations and low pH. Several small industries in Indonesia...