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J R Jarvis

Publications and source records attributed to J R Jarvis.

8 recordsLinked to original sources
PubMed2006

Comparative study of the photopic spectral sensitivity of domestic ducks (Anas platyrhynchos domesticus), turkeys (Meleagris gallopavo gallopavo) and humans.

1. The photopic spectral sensitivity of domestic ducks and turkeys was determined using an operant psychophysical technique. Spectral sensitivity was determined over a range of specified wavelengths, including UVA, between 326 < lambda < 694 nm and the results were directly compared with human spectral sensitivity measured under similar experimental conditions. 2. Domestic ducks and turkeys had similar spectral sensitivities to each other, and could perceive UVA radiation, although turkeys were more sensitive to UVA than ducks. For both species, peak sensitivity was between 544 < lambda < 577 nm, with reduced sensitivity at lambda = 508 and 600 nm. Both ducks and turkeys had a very different and broader range of spectral sensitivity than the human subjects tested. 3. Spectral sensitivity and UVA perception in these avian species are discussed in relation to their visual ecology and the mechanisms controlling neural processing of colour information.

Adult↗
PubMedDate not supplied

Audiological status of children with cleft palate. A review of 350 cases.

350 children treated for cleft palate at the children's Hospital of Cape Town, have been followed by periodic examination at the Audiological Unit of the Groote Schuur Hospital over a period of 7 years. The incidence of middle ear disease has been found to be over 60%. Its frequency and severity has been assessed and the progress of the hearing loss in individual cases during childhood years has been followed in many instances. The causation is discussed and methods of management described. The incidence is correlated with the type of operation performed for cleft repair and with the age at which it was done.

Child↗