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

AN EMPIRICAL TEST OF THE INTERVAL APPROACH FOR ESTIMATING RISK PREFERENCES

Previous attempts to measure agricultural decision makers' risk preferences have obtained values of the Arrow-Pratt coefficient in the range of approximately -.0002 to .0012. The recently developed interval approach for elicitation of risk preferences was used to estimate risk attitudes for Minnesota swine producers. Constant and decreasing absolute risk aversion were predominant among the sample. Seventy-eight percent of the respondents were in the Arrow-Pratt interval of -.0002 to .0003. A discriminant analysis using producer attributes and three estimated risk intervals concluded that 50 percent of the respondents could be classified in the correct risk interval.Risk and Uncertainty,

New evidence on the Fed's productivity in providing payments services

As the dominant provider of payments services, the efficiency with which the Federal Reserve provides such services in an important public policy issue. This paper examines the productivity of Federal Reserve check-processing offices during 1980-1999 using non-parametric estimation methods and newly developed methods for non-parametric inference and hypothesis testing. The results support prior studies that found little initial improvement in the Fed's efficiency with the imposition of pricing for Federal Reserve services in 1982. However, we find that median productivity improved substantially during the 1990s, and the dispersion across Fed offices declined.>Productivity ; Payment systems ; Check collection systems

Using Semantic Web Technologies to Support Enhanced Situation Awareness

The AKTiveSA project is using Semantic Web technologies to support information fusion and enhanced situational awareness in a simulated humanitarian relief scenario. We have developed an application that shows how situational awareness can be supported during humanitarian relief situations; often occurring alongside military conflict. Semantic Web technologies provide new opportunities for harvesting information from numerous, disparate and often heterogeneous information sources and can be used to better support complex knowledge fusion

Limited Effect of Y Chromosome Variation on Coronary Artery Disease and Mortality in UK Biobank

The effect of genetic variation in the male-specific region of the Y chromosome (MSY) on coronary artery disease and cardiovascular risk factors has been disputed. In this study, we systematically assessed the association of MSY genetic variation on these traits using a kin-cohort analysis of family disease history in the largest sample to date. METHODS: We tested 90 MSY haplogroups against coronary artery disease, hypertension, blood pressure, classical lipid levels, and all-cause mortality in up to 152 186 unrelated, genomically British individuals from UK Biobank. Unlike previous studies, we did not adjust for heritable lifestyle factors (to avoid collider bias) and instead adjusted for geographic variables and socioeconomic deprivation, given the link between MSY haplogroups and geography. For family history traits, subject MSY haplogroups were tested against father and mother disease as validation and negative control, respectively. RESULTS: Our models find little evidence for an effect of any MSY haplogroup on cardiovascular risk in participants. Parental models confirm these findings. CONCLUSIONS: Kin-cohort analysis of the Y chromosome uniquely allows for discoveries in subjects to be validated using family history data. Despite our large sample size, improved models, and parental validation, there is little evidence to suggest cardiovascular risk in UK Biobank is influenced by genetic variation in MSY

Building the foundation for environmental risk assessment at the Marcus Hook Refinery using geographic information systems

Center for Research in Water Resource