Perceptual assignment of opacity to translucent surfaces: the role of image blur

In constructing the percept of transparency, the visual system must decompose the light intensity at each image location into two components one for the partially transmissivc surface, the other for the underlying surface seen through it. Theories of perceptual transparency have typically assumed that this decomposition is defined quantitatively in terms of the inverse of some physical model (typically, Metelli's 'episcotister model'). In previous work, we demonstrated that the visual system uses Michelson contrast as a critical image variable in assigning transmittance to transparent surfaces not luminance differences as predicted by Metelli's model [F Metelli, 1974 Scientific American 230(4) 90 98]. In this paper, we study the contribution of another variable in determining perceived transmittance, namely, the image blur introduced by the light-scattering properties of translucent surfaces and materials. Experiment 1 demonstrates that increasing the degree of blur in the region of transparency leads to a lowering in perceived transmittance, even if Michelson contrast remains constant in this region. Experiment 2 tests how this addition of blur affects apparent contrast in the absence of perceived transparency. The results demonstrate that, although introducing blur leads to a lowering in apparent contrast, the magnitude of this decrease is relatively small, and not sufficient to explain the decrease in perceived transmittance observed in experiment 1. The visual system thus takes the presence of blur in the region of transparency as an additional image cue in assigning transmittance to partially transmissive surfaces.     

Fabry disease in genetic counseling practice: recommendations of the National Society of Genetic Counselors

The objective of this document is to provide health care professionals with recommendations for genetic counseling and testing of individuals with a suspected or confirmed diagnosis of Fabry disease, with a family history of Fabry disease, and those identified as female carriers of Fabry disease. These recommendations are the opinions of a multicenter working group of genetic counselors, medical geneticists, and other health professionals with expertise in Fabry disease counseling, as well as an individual with Fabry disease who is a founder of a Fabry disease patient advocacy group in the United States. The recommendations are U.S. Preventive Task Force Class III, and they are based on clinical experience, a review of pertinent English-language articles, and reports of expert committees. This document reviews the genetics of Fabry disease, the indications for genetic testing and interpretation of results, psychosocial considerations, and references for professional and patient resources. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a healthcare provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.     

The research subject as wage earner

Theoretical Medicine and Bioethics - The practice of paying research subjects for participating inclinical trials has yet to receive an adequate moral analysis.Dickert and Grady argue for a wage...     

Video games and aggressive thoughts, feelings, and behavior in the laboratory and in life

Two studies examined violent video game effects on aggression-related variables. Study 1 found that real-life violent video game play was positively related to aggressive behavior and delinquency. The relation was stronger for individuals who are characteristically aggressive and for men. Academic achievement was negatively related to overall amount of time spent playing video games. In Study 2, laboratory exposure to a graphically violent video game increased aggressive thoughts and behavior. In both studies, men had a more hostile view of the world than did women. The results from both studies are consistent with the General Affective Aggression Model, which predicts that exposure to violent video games will increase aggressive behavior in both the short term (e.g., laboratory aggression) and the long term (e.g., delinquency).     

Positive behavior support: Expanding the application of applied behavior analysis

Positive behavior support (PBS) is an approach to providing services to individuals who exhibit challenging behavior. Since its inception in the early 1990s, PBS has received increasing attention from the behavior-analytic community. Some behavior analysts have embraced this approach, but others have voiced questions and concerns. In this paper we describe the framework of PBS and show that it is consistent with the tenets of behavior analysis. Also, we illustrate how the framework of PBS might be used to guide practitioners and researchers in the field of applied behavior analysis. We hope to demonstrate that PBS offers useful suggestions regarding how applied behavior analysts can design and evaluate effective programs for people with developmental disabilities or behavioral challenges.     

Reviews of current books

Conclusion Wise counseling can relieve the anxiety and inner conflict of parents torn between the dread of their retarded offspring becoming a parent and the fear of an operation they believe to be illegal, immoral, and castrating.By knowing where to refer patients, clergymen can make it possible for some of these deprived members of society to find support and love within marriage without being overburdened by children they are not capable of rearing properly.     

How do speakers avoid ambiguous linguistic expressions?

Three experiments assessed how speakers avoid linguistically and nonlinguistically ambiguous expressions. Speakers described target objects (a flying mammal, bat) in contexts including foil objects that caused linguistic (a baseball bat) and nonlinguistic (a larger flying mammal) ambiguity. Speakers sometimes avoided linguistic-ambiguity, and they did so equally regardless of whether they also were about to describe foils. This suggests that comprehension processes can sometimes detect linguistic-ambiguity before producing it. However, once produced, speakers consistently avoided using the same linguistically ambiguous expression again for a different meaning. This suggests that production processes can successfully detect linguistic-ambiguity after-the-fact. Speakers almost always avoided nonlinguistic-ambiguity. Thus, production processes are especially sensitive to nonlinguistic- but not linguistic-ambiguity, with the latter avoided consistently only once it is already articulated.     

Is the curve relating temperature to aggression linear or curvilinear? A response to Bell (2005) and to Cohn and Rotton (2005)

P. Bell recommended examining the relationship between temperature and assaults during the hottest times of day and during the hottest months of the year. The authors' analyses of these data show a linear rather than inverted U-shaped relationship between temperature and assault during the hottest times of day and in the hottest months of the year. E. Cohn and J. Rotton recommended analyzing the 6 hr with the highest assaults versus the 6 hr with the lowest assaults. During high assault periods, there is a strong positive linear relationship between temperature and assault. During low assault periods, there is no relationship between temperature and assaults. Assaults and other violent crimes might decrease when temperatures are very hot, but the Minneapolis data set does not allow for testing of this hypothesis because Minneapolis is too cold.