Adaptation in the vertebral column: a comparative study of patterns of metameric variation in mice and men

In this paper we examine metamerism in the vertebral column of certain mammals from the perspectives of development and adaptation. To this end we examine the patterns of metameric variation of dimensions of the neural (vertebral) canal, vertebral body and spinous process in man and inbred strains of mice. The data from inbred strains of mice indicate that variability in dimensions within a strain reflects the temporal ordering and nature of developmental influences on vertebral morphogenesis. Differences between strains parallel the within-strain findings. These findings are attributed to somatic and neural influences on morphogenesis. Comparisons between mice and man indicate that these same influences can be invoked to explain and interpret the mosaic nature of vertebral column evolution. These findings lead us to conclude that different vertebral elements and levels are subject to different interactions of evolutionary and morphogenetic influences. The study of these influences and their interactions should prove fruitful in developing an understanding of the relationship between adaptation, development, growth and function in the skeleton generally

Physical Aspects of Cell Operation and Reliability

This chapter overviews the basic physical effects involved in programming and erasing of Flash memory cells, to provide the background for a deeper understanding of their operation and reliability. In particular, tunnelling and high field transport are treated and the associated phenomena in MOS-FETs and Flash cells are described by means of measurements and simulations. Device degradation induced by charge injection into thin silicon dioxide layers is also briefly discussed