No abstract

Summary Serum, eye secretions, post‐nasal swabs, external ear swabs and middle ear effusions (MEE) were collected from 131 Australian Aboriginal children with chronic otitis media with effusion (COME). The children were all resident in a trachoma endemic region. Chlamydia trachomatis was recovered from the MEE of 2 children. Probable bacterial pathogens were isolated from 34 (12·7%) ears. The remainder were sterile (52·4%) or contained normal skin flora (34·9%). Serum and secretions were examined by the micro‐immunofluorescent technique for the presence, titre and serotype of anti‐chlamydial antibody. Antibody, predominantly of the C serotype, was found in a high percentage of sera (80%) and secretions (approximately 50%). This serotype is associated with ocular trachoma. It is concluded that C. trachomatis is associated with COME among some Aboriginal children in this trachoma endemic area.

Previously we have emphasised the need for accurate picture matching and the proper convergence of left and right channels of a stereoscopic camera to ensure that the image is comfortable to view and does not cause fatigue. This usually procludes the use of standard zoom lenses in high quality 3D television cameras as the optical alignment frequently changes with focal length and two such lenses, when motorised, would have to be controlled with great accuracy to avoid viewer discomfort. This paper describes the on-going development of a compact zoom lens specifically for stereoscopic television in nuclear environments. Custom designed optics in radiation tolerant glass provide a focal length of 12.5mm to 36mm with a package length of less than 1 10mm. A novel method of encoding the position of the lens elements allows for very compact motonsation and a precision mechanism designed to overcome backlash ensures the stability of picture matching.The position of the lens elements is controlled by a 16 bit microcontroller and the control strategy allows focus and convergence to be maintained to a high degree of accuracy during zooming.2