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We examined the walking parameters of milking cows in relation to hoof trimming. The hooves of eight Holstein cows were trimmed. Two days before and after the hoof trimming, walking behavior, limb angles, back posture and vertical movement of the back while walking were measured. Walking rate (1.27 vs 0.87 m/s; P = 0.003), step length (1.46 vs 1.33 m; P = 0.009) and stepping rate (0.78 vs 0.65 steps/s; P = 0.046) were found to increase significantly after hoof trimming. Limb angles at the start and end of the support phase changed significantly after hoof trimming, thus indicating an improvement in the 'on tiptoe' appearance. The parameters relating to backline indicated that the marked arched shape of the back diminished after hoof trimming. Before hoof trimming, the positions of the withers varied widely and irregularly while walking; however, it changed after hoof trimming as the sinusoid curve and the range of vertical movement of withers decreased significantly. Overall, it has been quantitatively indicated that walking characteristics are improved after hoof trimming. The parameters used in the present study are expected to be useful for monitoring the walking characteristics of cows.

In the Nankai Trough subduction zone, a well-defined decollement characterizes the structure of the accretionary prism. Over the decollement are highly thrusted, accreted trench-wedge turbidites, whereas there are apparently stratified pelagic sediments below. A synthetic sonic log profile obtained from multichannel seismic data from Site 583 showed that the apparently stratified layer has a lower seismic velocity than the overlying accreted sediments. This inversion strongly suggests that the pelagic layer is overpressurized because interstitial water cannot be released through the sedimentary overburden. When the accretion of trench-wedge turbidites proceeds, major thrust faults extending to the decollement are generated and the overpressurized pore water is able to escape to the seafloor through the faults. As a result, the thrust fault plane yields reflections with reversed polarity and the pelagic layer often has normal velocity distribution beyond the major thrust zone.

A one‐dimensional gas hydrate accumulation model is developed to simulate the existence of hydrate in the Nankai Trough margin, where the total organic carbon content is extremely low. In order to study the accumulation of gas hydrate along a seismic profile, our model assumes an initial 1000 m thick turbidite sedimentation at the trench axis, and then the sediment experiences tectonic uplift to form the Nankai accretionary prism. Methane generated by microbial processes during the sedimentation is partly trapped in the pore space and partly migrated upwards due to compaction and subsequent porosity decrease at deeper levels. Upward methane gas flux from the deeper part (below 1000 m) is predicted by the model because the maximum thickness of the accreted sediment exceeds ten kilometers in the Nankai Trough accretionary prism. The basic geological parameters input to the model are those obtained from the ODP site 808, which was drilled at the lower inner trench slope. The methane hydrate stability zone is essentially controlled by bottom water temperature, regional heat flow and hydrostatic pressure. The simulation shows that methane hydrate will not accumulate in the Nankai Trough margin if only microbial methane generation is considered because the organic carbon content in the Nankai Trough area is as low as 0.75%. However, if we assume an upward flux of 5 kg of methane per square meters per 10,000 years, it will cause approximately 10 to 25% hydrate saturation under current physical conditions. The origin of the methane may be thermogenic and/or microbial. The resultant distribution of methane hydrate shows very good correlation with the distribution of the BSR.

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The objective of this study was to quantify nitrogen (N), phosphorus (P), and potassium (K) use and cycling in a dairy farming system. The data were collected from the experimental farm at the National Institute of Livestock and Grassland Science in Tochigi Prefecture, Japan, using about 11 ha of forage crop fields and about 30 dairy cows. Forage crops grown in the field were ensiled and offered to the cows, and the subsequent compost from the animals' excretion was applied to the field. The dairy farming system consisted of soil/crop, feed storage, animal, and compost components. Nutrient inputs and outputs and flows of the soil-plant-animal pathway for the whole farm and each component were measured for 5 years. Nutrient utilization was evaluated using nutrient balances, use efficiencies, and cycling indices. The 5 year average nutrient balances and nutrient use efficiencies of N, P, and K for the whole farm (kg ha -1 year -1 ) were 378, 97, and 199 and 0.25, 0.19, and 0.18, respectively. The characteristics of nutrient balances and use efficiencies for each component differed among N, P, and K. The average cycling indices of N, P, and K were 0.12, 0.11, and 0.37, respectively. Significant positive relationships between use efficiencies and cycling indices were observed in N and K. Year-to-year variations in flows were relatively large for compost application. The results suggested that improving N balance would be the most effective option for solving many of the environmental problems related to dairy farming.