In vitro but not in planta encapsidation of Rice gall dwarf virus core particles by the outer capsid P8 protein of Rice dwarf virus expressed in transgenic rice plants

Transencapsidation of the Rice gall dwarf virus (RGDV) inner core by the Rice dwarf virus (RDV) outer capsid P8 protein was examined in vitro and in planta. When RGDV core particles were incubated with an extract from RDV P8-transgenic rice leaf tissue, RDV P8 encapsidated the RGDV core particles to form double-shelled virus-like particles in vitro. In contrast, when RDV P8-transgenic rice plants were inoculated with RGDV, progeny RGDV particles contained RGDV P8 but RDV P8 was not detectable in the virions. No significant differences were found in acquisition by the vector insects and subsequent transmission rates between RGDV infecting nontransgenic rice plants and those infecting RDV P8-transgenic rice plants. These results indicate that mechanisms of and/or requirements for interactions between P8 and the inner core particles of phytoreoviruses differ between in vitro and in planta.     

Treatment of cow-waste slurry by a microbial fuel cell and the properties of the treated slurry as a liquid manure

Resource recycling and the proper treatment of animal waste to reduce its environmental impact are currently important issues for the livestock industry. A microbial fuel cell (MFC), a new type of bioreactor, is expected to play roles in both waste‐water purification and energy recovery. However, the generation of electricity from cow waste has not yet been examined. In this study, using an MFC, we examined the possibility of generating electricity from dairy‐cow waste slurry, and analyzed the properties of the treated slurry as liquid manure for resource recycling. The MFC treatment of the slurry generated electricity in a dose‐dependent manner, and the maximum power output by the MFC from a 1 g of chemical oxygen demand/L slurry was 0.34 mW/m². After the MFC treatment, 84% of the biological oxygen demand in the slurry was removed and three essential fertilizer elements (nitrogen, phosphorus, and potassium) were retained at 84, 70, and 91% levels, respectively. The amount of ammonia nitrogen in the slurry, as an element of fast‐release fertilizer, was increased by 1.9‐fold. Although the treated slurry displayed properties that made it preferable as liquid manure, further studies to improve the electrical power output by the MFC are required for practical use.     

Management approach using simple indices of deer density and status of understory vegetation for conserving deciduous hardwood forests on a regional scale

We investigated the validity and efficiency of a survey using sight per unit effort (SPUE) of sika deer and shrub-layer decline rank (SDR), which is an index of decline in the physical structure of a whole stand caused by sika deer, based on data collected on a broad scale. This survey was to be used to manage a deer population in order to conserve a forest ecosystem. First, we evaluated the spatial and temporal scales of deer density that are most appropriate for predicting decline in the status of understory vegetation. The model with SPUE calculated in a buffer with a radius of 4.5 km using data for the past 4 years was found to be the best. We showed that our knowledge of the relationship between deer density and status of shrub-layer vegetation is improved by identifying the most suitable spatial and temporal scales of SPUE for predicting SDR. Next, we quantified the effects of SPUE and environmental components on SDR in stands. We found that SPUE had the greatest effect on SDR among all explanatory variables. Moreover, the area under the curve (AUC) was large in a model that only used SPUE (AUC = 0.718). This result suggests that the variation in SDR among stands was explained well by SPUE regardless of differences in the forest environment. Furthermore, we identified the effective values of SPUE for preventing shrub-layer vegetation from declining through deer density control. We conclude that a management system based on SPUE and SDR is a simple and valid method for managing deer populations in order to conserve forest ecosystems.     

Prediction of the buckling stress of intermediate wooden columns using the secant modulus

We made several buckling tests of wooden columns with intermediate slenderness ratios () and examined the empirical formulas. On the basis of the examination, we formulated an equation for predicting the buckling stress () of an intermediate wooden column. Sitka spruce (Picea sitchensis Carr.) and buna (Japanese beech, Fagus crenata BI.) were used for the studies. A compressive load was applied on the specimen supported with pin ends, and the buckling stress was predicted by the tangent modulus theory and two empirical equations: those of Tetmajer and Newlin-Gahagan. The predicted - relations were compared with the test results, and the applicability of these predictions were examined. Based on the comparisons, we formulated an equation that can predict the - relations of materials with various stress-strain characters in the plastic strain range.     

Leaf-litter decomposition of 15 tree species in a lowland tropical rain forest in Sarawak: dynamics of carbon,nutrients, and organic constituents

The effects of tree species on the dynamics of nutrient transformations during leaf-litter decomposition are not well understood in tropical rain forests. To examine differences in the dynamics of C, nutrients, and organic constituents during decomposition among tree species, the leaf-litter decomposition of 15 trees was assessed using a litter-bag method in a lowland tropical rain forest in Sarawak. The dynamics of C was parallel to that of weight loss. The dynamics of nutrients were grouped into three patterns. The dynamics of K was characterized by a high leaching loss in the initial stages, and that of Ca and Mg generally showed a gradual decrease over the course of decomposition. The dynamics of N and P showed highly different patterns with the weight loss, and was characterized by relatively higher remaining mass at the end of the experiment. The variations or exceptions of nutrient dynamics among tree species were considered to be related to the initial concentration of each nutrient. For the dynamics of organic constituents, water-soluble carbohydrates disappeared quickly at the initial stages, and acid-soluble carbohydrates were the second fastest decomposing fraction; the decomposition of acid-insoluble residue (AIS) was the slowest. The release of limiting nutrients (N and P) generally followed the disappearance of AIS, but was independent of the disappearance of AIS when the initial concentrations of these nutrients were very low.     

Dyeability of Chemically Treated Wood and its Discoloration by UV-ray Irradiation

INTRODUCTION Wood is far from a stable material. One of the biggest challenges for woodworking is learning to work within the constraints of wood properties. Discoloration of wood directly influences the decorative performance of wood products. Therefore, the degree of color change is a critical factor that determines the utilization area of dyed wood (Sakuragawa Satoshi, 1996). Discoloration has occurred because the wood components and dye molecules are degraded by UV-ray (Kaneko Shin…     

Surface deterioration of wood-flour polypropylene composites by weathering trials

The market for wood-fiber plastic composites (WPCs) is expanding rapidly in many countries including Japan, where WPCs are mainly used for exterior products. In such applications, WPCs undergo undesirable color change, chalking, and shrinkage and swelling, and accordingly there is a need to better understand the mechanisms responsible for the weathering of WPC and develop methods of improving their weathering resistance. In this study, weatherability of WPC was assessed by natural and accelerated weathering trials. Discoloration (whitening) of WPC during exposure was caused by degradation of both wood and plastic. Darker color pigments as additives improved the color stability of WPC; however, chalking on the surfaces still occurred. The color stability of WPC was improved by application of exterior coatings. Preweathering of WPC (before coatings were applied) increased the absorption of coatings by the WPC and had a positive effect on the color stability and prevented chalking of the composites. Parts of this study were presented at the IUFRO XXII World Congress Meeting, Brisbane, August 2005 and the IAWPS 2005, Yokohama, November 2005     

Genetic variation ofAlnus trabeculosa populations in Japan

Alnus trabeculosa Hand.-Mazz. is classed as “near threatened,” and efforts should be made to conserve the species, but effective action would require understanding of its genetic variation and structure. Therefore, the genetic variation at 12 isozyme loci was examined in seven populations of the species in Japan. The expected heterozygosity within species (H _es=0.222) and the expected heterozygosity within populations (H _ep=0.199) were found to be slightly higher than in most other woody species. The coefficient of genetic differentiation (G _ST=0.146) was also high. The northernmost population had the lowest values for almost all measures of genetic variation, and populations in southern Japan tended to show greater within-population variation than those in northern Japan. The level and distribution of genetic variation in this species might be related to its life history and ecological traits, and distribution history.     

Automatic detection of washboarding in bandsaws

This paper presents an on-line method for detecting washboarding generated in bandsaws. It uses a parameter based on the shape of sawing force amplitude distributions. The curve of the probability density function of the parallel sawing force amplitude obeyed a normal distribution for the normal sawn surface, but it changed to an M-shaped distribution when washboarding appeared on the sawn surface of the workpiece. The curve of probability density function of the normal sawing force amplitude obeyed the normal distribution for any sawn surface investigated. The workpiece including a knot did not influence use of the parameter for detecting the appearance of washboarding.