Abstract— The u.v. transmission characteristics of various epidermal specimens prepared by various methods were measured by a recording spectrophotometer and integrating spheres. Although suction or stretch and heat produced the most satisfactory specimens, transmission data obtained from all specimens were similar and generally resembled that reported by previous investigators. The important contribution of forward scattering to total transmitted light was demonstrated. Significant numbers of u.v. photons have been shown to penetrate to the dermis and papillary capillaries. Erythema was produced in vivo by monochromatic light filtered through epidermal specimens after exposure of skin to the quantity of u.v. anticipated by these data.
Apoptosis is a process found in many tissues by which devitalized cells are eliminated in an orderly manner. In skin, apoptosis occurs following sunburn, in Bowen's disease and in basal cell carcinoma. Scattered cells are observed in which the cytoplasm has become condensed and dyskeratotic. These dyskeratotic cells are phagocytized, either in toto or in fragments by surrounding keratinocytes. This process involves the condensation, fragmentation, phagocytosis and digestion of individually degenerated cells. The mass of a tissue is thus related to the balance between cell formation (mitosis) and cell destruction (apoptosis). In epidermal and other surface tissues, the rate of exfoliation must also be considered.
Many areas of social research show that images of the future influence behavior. There is evidence that traditional images of the future are becoming less believable and that we are becoming less hopeful about the future. This article explores emerging images of a sustainable society to assess their potential for renewing our sense of hope and social purpose. Four different images or scenarios are set out of the level of change that may be required to reach a sustainable future. Rough quantitative estimates are used to test the feasibility of the scenarios. The analysis suggests that most of these scenarios are well within the realm of physical possibility. It also shows that emerging images of a sustainable society have the characteristics possessed by other images of the future that have been highly influential in Western history and in other cultures. They are believable, highly positive, and open‐ended, inviting further elaboration. They specifically respond to key challenges facing our society. And they set out a story of “what is happening” and “what could be” that provides an integrative perspective on the significance of today's events and choices.
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