Mandibular Layering in Delphinapterus leucas and Age Determination
LAWS1 investigated mandibular periosteal layers as an aid to ageing the Sperm whale Physeter catodon. Continued studies of P. catodon indicate that mandibular layers and tooth layers occur in equal numbers2, and it has been postulated that two tooth layers are deposited annually3. Two tooth and one mandibular layer in Delphinus delphis are annual4.
Lead acetate as a marker of growing calcified tissues a modified method
The pattern of growth of bone and dentin was studied in serial decalcified sections by the use of lead markings. The experimental animals (monkeys and rabbits) received repeated intravenous injections of 4 mg lead acetate/kg body weight. The tissues were decalcified in 1% HCl through which H2S was constantly bubbled. Serial frozen sections were cut at 15–20 μ embedded in 10% gelatin and mounted in polyvinyl pyrollidone. They were placed in a 0.1% solution of gold chloride for ten minutes and then immersed for the same length of time in a 5% solution of sodium bisulphate in order to tone the background tissues. The sections were transferred to distilled water until the tissues became pink. When the desired toning was obtained they were fixed in 5% sodium thiosulphate. The examination of the sections obtained by this method confirmed the data obtained by other vital marking methods. However, much finer detail could be observed due to the sharpness of the lines and the use of relatively thin decalcified sections.
The Problems and Opportunities in Developing International Business Programs
This paper discusses the results of a survey conducted among AACSB member schools. The survey dealt with two major topical areas. These were (a) what types of International Business programs currently exist in AACSB Schools, and (b) problems associated with these programs. The paper also suggests countries that offer opportunities to Colleges of Business to pursue countty-specific programs.