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AbstractSome stability criteria for walking vehicles on rough terrain are discussed in this paper. Several criteria for stability margin were proposed up to now, but those can be roughly divided into three categories. This paper compares them each other and concludes that a stability criterion based on energy consideration is the most reasonable for practical use through simple experiments. But the existing stability margin is apparently inadequate because it varies with weight of the vehicle with the same posture, while weight doesn't affect its resistance to the tumble. Therefore, the improved stability margin normalized by weight is proposed here. At the same time, a helpful tool to derive the desirable posture for walking vehicles is described which can maximize the proposed stability margin on rough terrain.

Chondrodysplastic dwarfism in Japanese brown cattle is an autosomal recessive disorder characterized by short limbs. Previously, we mapped the locus responsible for the disease on the distal end of bovine chromosome 6. Here, we narrowed the critical region to Ϸ2 cM by using linkage analysis, constructed a BAC and YAC contig covering this region, and identified a gene, LIMBIN (LBN), that possessed disease-specific mutations in the affected calves. One mutation was a single nucleotide substitution leading to an activation of a cryptic splicing donor site and the other was a one-base deletion resulting in a frameshift mutation. Strong expression of the Lbn gene was observed in limb buds of developing mouse embryos and in proliferating chondrocytes and bone-forming osteoblasts in long bones. These findings indicate that LBN is responsible for bovine chondrodysplastic dwarfism and has a critical role in a skeletal development.

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