Effect of third-order aberrations on dynamic accommodation

We investigate the potential for the third-order aberrations coma and trefoil to provide a signed cue to accommodation. It is first demonstrated theoretically (with some assumptions) that the point spread function is insensitive to the sign of spherical defocus in the presence of odd-order aberrations. In an experimental investigation, the accommodation response to a sinusoidal change in vergence (1–3 D, 0.2 Hz) of a monochromatic stimulus was obtained with a dynamic infrared optometer. Measurements were obtained in 10 young visually normal individuals with and without custom contact lenses that induced low and high values of r.m.s. trefoil (0.25, 1.03 μm) and coma (0.34, 0.94 μm). Despite variation between subjects, we did not find any statistically significant increase or decrease in the accommodative gain for low levels of trefoil and coma, although effects approached or reached significance for the high levels of trefoil and coma. Theoretical and experimental results indicate that the presence of Zernike third-order aberrations on the eye does not seem to play a crucial role in the dynamics of the accommodation response.

A structured return to the 'Fourth Estate': interviews and inquiry that challenge entrenched authorities' 'knowledge'

Contemporary debates on the role of journalism in society are continuing the tradition of downplaying the role of proactive journalism - generally situated under the catchphrase of the Fourth Estate - in public policy making. This paper puts the case for the retention of a notion of a proactive form of journalism which can be broadly described as "investigative ", because it is important to the public policy process in modern democracies. It argues that critiques that downplay the potential of this form of journalism are flawed and overly deterministic. Finally. it seeks to illustrate how journalists can proactively inquire in ways that are relevant to the lives ofpeople in a range of settings, and that question elite sources in the interests ofthose people.

The relationship between closeness to significant others and self-esteem

One hundred and forty-three children (61 boys and 82 girls) between 8 and 12 years of age participated in a study which focused on closeness to significant others and its relationship with self-esteem. A closeness rating scale was developed to determine quantitatively how close children feel to their mother, father, two closest peers, and current teacher. Marsh's (1990) eight general self-concept items from the Self-Description Questionnaire 1 (SDQI), together with eight items from Burnett's (1994) Self-scale, were administered to the children, who ranged in age from 8 to 12 years, to measure their self-esteem. Closeness to mother was found to correlate most significantly with a child's self-esteem, while closeness to teacher was related more strongly to self-esteem for girls than for boys.