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The long-eared owl (Asio otus) and short-eared owl (A. flammeus) are indistinguishable by bone morphology alone. Since they inhabit contrasting ecological situations, identification of their bones from prehistoric sites is important for paleoenvironmental interpretations. Measurements on long bones of modern specimens indicate these species can be identified by bone size. Tables are presented for use by the analyst in identifying complete or fragmentary wing and leg bones. Owl bones and feathers frequently occur in archaeological sites in North America, and most species are osteologically distinct and can be identified with little difficulty by the faunal analyst with an adequate comparative collection. However, two species, the long-eared owl (Asio otus) and short-eared owl (A. flammeus) are extremely similar in bone structure and cannot be safely and accurately identified by bone morphology alone. Since these species inhabit contrasting ecological situations, their exact identification in prehistoric sites can help refine paleoenvironmental interpretations. The long-eared owl inhabits brushy and wooded areas; it nests usually in shrubland, canyons, and evergreen forests (Hubbard 1978) but may nest even in oakhackberry-mesquite associations in the Lower Sonoran Desert (Phillips et al. 1964). The shorteared owl typically inhabits open plains and grasslands, marshes (Bent 1938), and large, open fields. Both species occur widely across North America (American Ornithologists' Union 1957) and Eurasia; there appears to be no geographic size variation in either species in North America. In studying a series of archaeological and modern specimens, I found these species can be distinguished by bone measurements.

Clinical testing of a mouthrinse and a dentifrice containing fluoride. A two-year supervised study in school children

A dozen new radiocarbon dates, together with a thorough review of its fossil distribution, shed new light on the time and probable cause of extinction of the California condor, Gymnogyps californianus, in Grand Canyon, Arizona. The radiocarbon data indicate that this species became extinct in Grand Canyon, and other parts of the inland West, more than 10,000 years ago in coincidence with the extinction of megafauna (proboscidians, edentates, perissodactyls). That condors relied on the megafauna for food is suggested by the recovery of food bones from a late Pleistocene nest cave in Grand Canyon. These fossil data have relevance to proposed release and recovery programs of the present endangered population of California condors.

Enzymes operate at optimal temperatures, and that is presumably the reason why the body temperature of homeotherms is kept within such narrow limits: a rise of 6°C seems always to lead to death [71]. If man is to remain in thermal equilibrium, the heat gained by his body must balance its losses (Table 8.1).

The general practitioner with loyal and regular patients is in a good position to undertake long-term clinical trials of periodontal treatment. Ethically, these should be comparisons of agents or procedures acknowledged to be beneficial but lacking confirmation of the long-term effects. Standardized bite-wing radiographs can represent a valuable record in this type of study.

This brief paper describes the construction and method of use of a periodontal probe specifically designed for the assessment of the periodontal treatment needs of populations.

The protective role of cementum against root resorption is discussed in relation to buried teeth, orthodontic treatment, replantation and periodontal disease. The essential feature seems to be a layer of partially calcified precementum or vital cementoblasts. Root resorption close to the epithelial attachment, although not common, is probably the result of death of cementoblasts caused by irritants from bacterial plaque, and the presence of severe of prolonged inflammation. Cementum exposed in the pocket can be affected in different ways by these irritants, and rendered unacceptable for re-attachment to periodontal tissue. Successful re-attachment procedures involve either the removal of the affected cementum or its treatment with agents partially to decalcify such as acids, or detoxify by phenol for example. Examples of treatment embodying some of these principles are illustrated by two case histories of localised gingival recession and one of intra-bony pocketing associated with an acute lateral periodontal abscess. In this case a follow-up radiograph taken 16 years later is presented as evidence of the permanence of repair which can be achieved. Root resorption which often follows the use of fresh autogenous bone from the ilium is then discussed and the conclusion reached that the vital cells in the transplant discourage the migration of cementoblasts from the adjacent periodontium. The cementum and dentine thus remain unprotected and susceptible to resorption.

A prospective study was made of 80 patients during typical clinical episodes of acute myocardial infarction with biochemical and scalar electrocardiographic confirmation. Nine patients had bundle-branch block and 12 had had previous episodes of myocardial infarction. Serial electrocardiograms and vectorcardiograms were recorded during the first week in hospital. The most striking finding was that in more than half the cases there was disagreement between the electrocardiogram and vectorcardiogram in the localizationof infarction. The earliest evidence of infarction in the electrocardiogram is often restricted to ST and T changes though in the corresponding vectorcardiograms evidence of infarction may be present in the QRS loop. In those cases in which both electrocardiogram and vectorcardiogram show QRS abnormalities these are frequently detected earlier in the vectorcardiogram, but the converse is rare.

High levels of serum-enzyme activities, particularly of creatine kinase and " α-hydroxybutyrate dehydrogenase", have been found during a study of 25 patients with accidental hypothermia. The results suggest that accidental hypothermia causes profound cellular damage, particularly of skeletal and cardiac muscle. This may help to explain the high mortality and the characteristic changes in the electrocardiogram found in such circumstances. These findings may be important in the use of hypothermia in surgery.