Change blindness: size matters

It is easy to detect a small change between two sequential presentations of a visual stimulus, but, if they are separated by a blank interval, performance is around chance. This change blindness (CB) can be rectified, or improved, by cueing the spatial location of the change either in the first stimulus or the interval; however, no advantage is conferred when the cue appears during the second presentation of the stimulus. This supports the idea that a representation of the first stimulus is formed and persists through the course of the interval before being 'overwritten' by the second presentation of the stimulus (Landman et al, 2003 Vision Research 43 149 - 164). We were interested in the time course of the cueing effect during the interval. Following Landman et al, our first stimulus was an array of eight rectangles defined by texture and there was a 50% chance that one of the rectangles would change orientation in the second stimulus. Five cues were used, one within the first stimulus, three across the interval, and one in the second stimulus. Only one of these cues appeared in each trial. The cued rectangle was the one that would change between the first and second stimulus when a change occurred. The cue was a yellow line. Eighty-five observers showed the characteristic cueing performance supporting 'overwriting', but performance decreased over the duration of the interval suggesting that the initial representation of the first stimulus fades over time. However, when the size of the rectangles was increased, performance across the interval improved significantly. We consider two possible explanations: one is that simply by increasing rectangle size we raise the storage capacity for the number of rectangles in our representation, the other is that storage is related to task difficulty

Sexual abuse risk in sport: Testing the ‘stage of imminent achievement’ hypothesis

The purpose of this study was to assess the hypothetical model outlined by Brackenridge and Kirby in IRSS in 1997 (32(4): 407-418) which suggested that athlete susceptibility to grooming and sexual abuse in sport coincides with a defined stage of athletic development just prior to peak success: this period they called the ‘stage of imminent achievement’ (SIA). The model was assessed by investigating 83 cases of criminally-defined child sexual abuse within the sport context that had been reported in the print media over a period of 15 years. SIA-related hypotheses were examined in relation to athlete performance level, sex and early- and late-specialisation sport types. The majority of cases of child abuse in the sample occurred below the SIA for both males and females and with sexually abused males being three times more likely to be aged below the SIA than their female athlete victim counterparts. Age below the SIA thus appears to be a stronger predictor of the timing of sexual abuse among male athletes than females: this suggests that much more research is needed on both age and gender differences in sport-related sexual victimisation. Several limitations of the data are discussed. It is recommended that the SIA be reconceived as both a relational and a developmental construct and examined more closely in relation to the increased dependence of the athlete on their coach just as they approach a performance goal

Failure modes of an alumina-based machining ceramic

Attempts have been made to reproduce "comb" cracks in disposable cuboid alumina tool tips as a preliminary to an investigation into catastrophic failure during machining. During lathe tests the tips withstood rates of machining several times greater than the normally accepted "comb" crack thresholds. Chemical analysis revealed the anomalous presence of calcia in the current tips which was thought to be responsible for the presence of a liquid phase during sintering. Examination by electron microscopy of the broken tool tips revealed a predominance of intergranular fracture and two distinct modes of transgranular cleavage, one of which was influenced by pore concentrations in geometric patterns. Moduli values were some 40% lower than previously used batches of tips, which permitted the absorption of greater strain induced by either mechanical or thermal sources. No damage was evident in the tool tips after the first cut up to a feed rate of 0.03125 in/rev but catastrophic failure always occurred at the instance of re-engagement at feed rates of 0.028 in/rev or greater. The difference in chemical analysis, porosity and modulus would appear to be responsible for the absence of "comb" cracking and for the phenomenon of catastrophic failure. A test rig was designed for operation on an induction heater to simulate the condition of abrupt disengagement during machining. Failure thresholds were established for a variety of induction coils under closely controlled conditions of heatining and loading

Satellite monitoring of sea surface pollution

The author has identified the following significant results. Image processing techniques developed are well adapted to the exploration and isolation of local areas which exhibit small temperature differences between themselves and their surroundings. In the worst case of imagery of small areal extent of sea surface having no coastal boundary in the area, there is yet no method of distinguishing unambiguously an oil spill from fog, cloud, the effect produced by shallow sediments, or the effects of naturally occuring thermal fronts. In the case of uniform slicks of liquid North Sea oil in still air, laboratory simulation experiments show that, for oil thicknesses in excess of 1 or 2 mm, there is, under equilibrium conditions, little dependence of oil surface temperature on the thickness of the oil layer. The surface temperature of oil is consistently higher than that of water, the difference being about 1 K at low values of relative humidity, but tending to increase as the relative humidity increases

A Book of Conversations: Trauma, Representation, and Reconstruction in Lewis Carroll\u27s Alice\u27s Adventures in Wonderland

For over 150 years, critics and readers have struggled to understand the meaning of Lewis Carroll\u27s Alice\u27s Adventures in Wonderland. Through Alice, Carroll asserts that a focus on conversations in Wonderland will illuminate the use, or value, of his novel. The conversations between Alice and other characters reveal that Alice experiences a breakdown of her reality that mirrors the symptoms of trauma. Thus, looking through Alice\u27s deconstructive process through the lens of trauma can provide insight into the value of Carroll\u27s novel. Yet the novel does not describe a known source of trauma. Instead of emphasizing the traumatic event itself, Carroll focuses on the deconstructive and reconstructive process a victim experiences as they face the effects of trauma. Within the safe distance of the novel, readers can fall down the rabbit hole and enter Wonderland, a place where they can play with the boundaries of reality, explore how language represents a deconstructed reality and influences the reconstruction of reality, and prepare to face the small and large traumas of life