It is shown that the Banachiewicz identity concerning the inverse of a partitioned matrix is useful in discussing some characterizations of inverse-positive matrices. The Hawkins-Simon condition as well as the Georgescu-Roegen condition come out in a natural way.

Correspondence: Dr Hamilton, Department of Otolaryngology–Head and Neck Surgery, Division of Facial Plastic and Reconstructive Surgery, University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242 ([email protected]). Financial Disclosure: None reported. Additional Contributions: Norman Koren, MA, of Imatest provided his insights on camera testing and image analysis, and...

A technique for performing core biopsies of indeterminate masses of the extracranial head and neck is described. Four patients with suspicious masses of the extracranial head and neck underwent coaxial core biopsies through an 18-gauge Hawkins-Akins blunt tip needle. Three of the four patients had diagnostically adequate samples. There were no neurologic or vascular complications.

During the adaptive immune response, lymphocyte populations undergo a characteristic three-phase process: expansion through a series of cell divisions; cessation of expansion; and, finally, most of the accumulated lymphocytes die by apoptosis. The data used, thus far, to inform understanding of these processes, both in vitro and in vivo, are taken from flow cytometry experiments. One significan...

REFERENCES tions arising from the intluences of host and parasitoid phenologies (3). Single values cannot characterize host-parasitoid interactions, and maximum values are unlikely to be typical over longer times or in different areas (4). 4) Contrary to the prediction made by Hawkins et al., successful biological control can result from the use of agents that are characterized by low rates of ...

It is well established that hepatic abnormalities may occur in patients with rheumatoid arthritis (RA) and other connective tissue disorders and these changes have usually been attributed to the systemic nature of the underlying disease process. Abnormalities reported include minor derangements of liver function (Movitt and Davis, 1953) and other abnormalities which have been related to the sev...