Calculation of optical trapping landscapes

Manipulation of micrometer sized particles with optical tweezers can be precisely modeled with electrodynamic theory using Mie's solution for spherical particles or the T-matrix method for more complex objects. We model optical tweezers for a wide range of parameters including size, relative refractive index and objective numerical aperture. We present the resulting landscapes of the trap stiffness and maximum applicable trapping force in the parameter space. These landscapes give a detailed insight into the requirements and possibilities of optical trapping and provide detailed information on trapping of nanometer sized particles or trapping of high index particles like diamond.

User satisfaction with allied health services delivered to residential facilities via videoconferencing

We have investigated the role of videoconferencing in allied health service provision to high-care clients in rural residential facilities. Videoconferencing equipment was set up at a rural aged-care facility and a metropolitan allied health centre; ISDN transmission at 384 kbit/s was used to link the equipment. Twelve residents were assessed by both videoconference and face to face across five allied health disciplines (a total of 120 assessments). User satisfaction was measured using questionnaires and focus groups. Face-to-face assessment took significantly longer than videoconferencing assessment. However, the mean satisfaction ratings for face-to-face assessments were higher than for videoconferencing and the majority of the staff preferred the face-to-face format. Videoconferencing was particularly useful for consultations and the initial stages of the assessment process. A number of issues relating to the videoconferencing equipment, to the environment in which assessments were performed and to the clients themselves need to be addressed in order for this form of service delivery to be effective.