Biomedical subjects

R H Gifford

Publications and source records attributed to R H Gifford.

11 recordsLinked to original sources

PubMed2000

Contributions of suppression and excitation to simultaneous masking: effects of signal frequency and masker-signal frequency relation.

This study investigated the contributions of suppression and excitation to simultaneous masking for a range of masker frequencies both below and above three different signal frequencies (750, 2000, and 4850 Hz). A two-stage experiment was employed. In stage I, the level of each off-frequency simultaneous masker necessary to mask a signal at 10 or 30 dB sensation level was determined. In stage II, three different forward-masking conditions were tested: (1) an on-frequency condition, in which the signals in stage I were used to mask probes of the same frequency; (2) an off-frequency condition, in which the off-frequency maskers (at the levels determined in stage I) were used to mask the probes; and (3) a combined condition, in which the on- and off-frequency maskers were combined to mask the probes. If the off-frequency maskers simultaneously masked the signal via spread of excitation in stage I, then the off-frequency and combined maskers should produce considerable forward masking in stage II. If, on the other hand, they masked via suppression, they should produce little or no forward masking. The contribution of suppression was found to increase with increasing signal frequency; it was absent at 750 Hz, but dominant at 4850 Hz. These results have implications for excitation pattern analyses and are consistent with stronger nonlinear processing at high rather than at low frequencies.

Acoustic Stimulation↗

PubMed1996

A model for distributing teaching funds to faculty.

Teaching at medical schools has been supported principally through research and clinical income, but these resources have become more scarce, faculty have begun to look elsewhere for support of student teaching. Yale University School of Medicine has developed a model for distributing a portion of general revenue funds to departments based entirely on their faculty members' commitment to the teaching of undergraduate medical students. This model combines both a qualitative measure (effectiveness) and a quantitative measure (effort) to assess the commitments of faculty to teaching. Initial response has been primarily positive. Both faculty members and chairs have acknowledged that faculty should receive financial support for major teaching responsibilities. Although the amount of funding may not be proportional to the actual effort of faculty members, by apportioning tuition dollars for teaching Yale hopes to send a powerful message about its commitment to its teaching faculty and to its medical students.

Budgets↗

PubMed1974

Characterization of a human acute phase protein found in association with rubella virus infection.

A precipitating antigen, rho, was first detected in the blood of persons with rubella and in rubella virus-infected cell culture fluids (1). Partially purified antigens from both sources were examined and shown to have similar properties, although antigen from serum sedimented more heterogeneously, with estimated coefficients from 15 to 21 S, while that from culture fluids sedimented in the 11-14 S region. In each case, antigen was located in the beta-1 zone after electrophoresis in agarose, and at a density of 1.305 g/ml after centrifugation in CsCl. Stability characteristics were typical of protein antigens. Immunofluorescent microscopy revealed that rubella virus induced the appearance of rho antigen scattered throughout the cytoplasm of infected cells. When cells containing antigen were exposed for 24 h to 5 microg/ml actinomycin D rho was no longer detectable, indicating the probable cellular origin of the antigen. Also, titers in medium of infected cultures showed a reduction after actinomycin treatment, but levels of the virus-specified antigen, iota, were relatively unaffected. Rho appears to be a protein common to man and many animals. In vitro, it was induced by rubella virus and by adenovirus. In vivo, rho titers were shown to be elevated after rubella virus infection and, to a lesser extent, after infection with certain other viruses. High titers were also demonstrated in women late in pregnancy and in patients with rheumatoid arthritis. In man and the chimpanzee, the appearance and decline of rho in the blood after rubella virus infection were temporally similar to the patterns of CRP, although rho seemed to be a more sensitive indicator of infection. The data presented indicate that rho is a newly recognized acute phase protein inducible by certain virus infections and by other unidentified stimuli present prominently in pregnancy and rheumatoid arthritis.

Animals↗

PubMed1973