Age estimation in bowhead whales using tympanic bulla histology and baleen isotopes
Arctic; Balaena; Balaena mysticetus; bone; carbon; corpora; GLGs; growth; LAGs; layers; Marine & Freshwater Biology; minke whales; stable isotopes; tympanic bulla; Zoology
Tympanic bullae and baleen plates from bowhead whales of the Western Arctic population were examined. Growth layer groups (GLGs) in the involucrum of the tympanic bone were used to estimate age of the whales, and compared to stable isotope signatures along transects of baleen plates and the involucrum. The involucrum of the tympanic bone consists of three regions that form in utero, during nursing in the first year, and during the first decades of life, respectively. Life history events, such as annual migration, are recorded in the bowhead tympanic bulla. It is likely that bone growth in the bowhead tympanic occurs during periods of high food intake, while slow or arrested growth occurs during periods of low food intake. Comparisons between numbers of GLGs in the tympanic, number of isotopic oscillations in a baleen plate, length of the baleen plate, and total whale length show correlation coefficients as high as 0.97. The tympanic GLG method is particularly useful for estimating the age of whales up to 20 yr old.
Sensor J D; George J C; Clementz M T; Lovano D M; Waugh D A; Givens G H; Suydam R; Stimmelmayr R; Thewissen J G M
Marine Mammal Science
2018
2018-04
Journal Article
<a href="http://doi.org/10.1111/mms.12476" target="_blank" rel="noreferrer noopener">10.1111/mms.12476</a>
Spine update - Lumbar interbody cages
anterior; arthrodesis; bone; cages; carbon; composite; fusion; interface; in-vitro; lumbar spine; material orthopedic implants; model; Neurosciences & Neurology; Orthopedics; wear
Interbody cage devices, used to assist interbody fusion, are rapidly gaining popularity in the surgical management of chronic low back pain. This update provides a structural classification of commonly used devices and assesses them against a set of clearly defined surgical goals, including ability to correct the existing mechanical deformation, ability to provide mechanical stability, ability to provide a suitable environment for arthrodesis, and ability to limit "built-in" morbidity. In addition, the materials used in the devices are examined regarding their biomechanical, biologic, and radiographic characteristics.
Weiner B K; Fraser R D
Spine
1998
1998-03
Journal Article
<a href="http://doi.org/10.1097/00007632-199803010-00020" target="_blank" rel="noreferrer noopener">10.1097/00007632-199803010-00020</a>