Effects of chronic acid fog exposure with soil acidification or nitrogen loading on nutrient status in Abies firma seedlings

To clarify the nutrient status in momi fir (Abies firma Sieb. et Zucc.) seedlings under complex stress conditions of acid fog with soil acidification or nitrogen loading, we exposed seedling shoots to simulated acid fog (pH 3) and simultaneously loaded the soil with acid or excess nitrogen for 17 months. Proton and nitrogen loading reduced K concentration in soil, but these treatments had little effect on the nutrient status of fine roots in momi fir seedlings. Acid fog exposure resulted in reduced concentrations of Mg, Al, and Fe in current-year needles and Mg, Al, Cu, Fe, and Zn in 1-year-old needles. The complex effects of acid fog exposure with proton or nitrogen loading on nutrient status were relatively slight. However, elements such as Al and Cu notably reflect the effects of proton loading. These results show that the nutrient status of trace elements, rather than major elements, in needles of momi fir seedlings is sensitive to exposure to acid fog or proton loading.     

Fire protection of a laminated veneer lumber joint by wood carbon phenolic spheres sheeting

Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002     

Life history and ecology of the glowbelly <Emphasis Type="Italic">Acropoma japonicum</Emphasis> in the Uwa Sea,Japan

ABSTRACT:   The life history and ecology of the glowbelly Acropoma japonicum a commercially important fishery resource, were investigated in the Uwa Sea, Japan. Newly settled juveniles (0⁺) appeared at the end of the breeding season and reached maturity in the next season, i.e. when they became yearlings (1⁺). The yearlings made a gametic effort comparable to that of older fish. During the breeding season, the somatic conditions were more deteriorated for males than for females. That the deterioration of male somatic conditions was not attributable to a sexual difference in energy gain from feeding suggests that the males incurred higher energetic costs of reproduction despite their relatively low gonadosomatic indices. Such an energy depletion may increase the mortality risk, resulting in female-biased sex ratios in the older age classes. Most of the 1⁺ fish disappeared in winter following their first breeding. For A. japonicum , the observed precocity and short life span is notable because it is a higher consumer that is generally expected to show later maturation and longer life. As possible explanations for their disappearances, predation and postbreeding emaciation were less likely. While fishing is one of the most influential factors, the possibility of age-specific migration toward deeper waters remains to be examined.     

Role of oocyte‐derived paracrine factors in follicular development

Mammalian oocytes secrete transforming growth factor β (TGF‐β) superfamily proteins, such as growth differentiation factor 9 (GDF9), bone morphogenetic protein 6 (BMP6) and BMP15, and fibroblast growth factors (FGFs). These oocyte‐derived paracrine factors (ODPFs) play essential roles in regulating the differentiation and function of somatic granulosa cells as well as the development of ovarian follicles. In addition to the importance of individual ODPFs, emerging evidence suggests that the interaction of ODPF signals with other intra‐follicular signals, such as estrogen, is critical for folliculogenesis. In this review, we will discuss the current understanding of the role of ODPFs in follicular development with an emphasis on their interaction with estrogen signaling in regulation of the differentiation and function of granulosa cells.     

Interannual variability of the ecosystem of the Kii Channel, the Inland Sea of Japan, as influenced by bottom intrusion of cold and nutrient-rich water from the Pacific Ocean, and a recent trend of warming and oligotrophication

Interannual variability of the ecosystem of the Kii Channel, productive shelf water on the Pacific side of south‐western Japan, was analysed based on physicochemical environmental variables and abundance of major zooplankton taxa collected monthly for 12 yr from 1987 to 1999. The Kii Channel experienced both short‐term (i.e. 3–4 yr) cyclical changes and a long‐term (i.e. decadal) environmental trend. The short‐term variability was primarily associated with year‐to‐year differences in intrusion of subsurface, cold nutrient‐rich water along the bottom of the Kii Channel from the Pacific Ocean. When this bottom intrusion was intense, the Kii Channel experienced a cold, new production‐dominated ecosystem. The bottom intrusion, however, has become less intense in recent years, because of the closer proximity of the Kuroshio flow axis to the Kii Channel. Hence, there was a consistent trend towards warming and a regenerated production‐dominated ecosystem. In accordance with such environmental changes, the zooplankton community shifted towards more oceanic conditions; major herbivorous calanoids (i.e. Calanus sinicus, Paracalanus parvus (s.l.), Clausocalanus spp. and Acartia omorii) decreased, while carnivores (i.e. hydromedusae and Sagitta spp.) increased. The amount of total fish catch also decreased, while the catch of subtropical species increased. These findings lead us to conclude that the bottom intrusion from the Pacific Ocean plays a key role in determining the biological production in the Kii Channel.     

EMG telemetry studies on upstream migration of chum salmon in the Toyohira river,Hokkaido, Japan

The movements of 28 adult chum salmon, Oncorhynchus keta (Walbaum) tagged with electromyogram (EMG) transmitters were tracked along the Toyohira river, Hokkaido, Japan, in October of 2007 and 2008 to investigate and evaluate the upstream migratory behavior through the protection bed and fishway of ground sills. The approach time of fish that ascended successfully through the protection bed and fishway was shorter than that of unsuccessful fish. The unsuccessful fish were observed to swim in currents with high water velocity and shallow water depth at swimming speeds that exceeded their critical swimming speed (U _crit) during the approach to these structures. In consequence, unsuccessful fish frequently alternated between burst and maximum sustained speeds without ever ascending the fishway, and eventually became exhausted. It is important that fishway are constructed to enable chum salmon to find a passage way easily, so that they can migrate upstream rapidly without wasting excessive energy.