Mechanisms of verbal memory impairment in four neurodevelopmental disorders

Profiles of verbal learning and memory performance were compared for typically developing children and for four developmental disorders characterized by different patterns of language functioning: specific language impairment, early focal brain damage, Williams Syndrome, and Down Syndrome. A list-learning task was used that allowed a detailed examination of the process of verbal learning, recall, and recognition (California Verbal Learning Test--Children's Version). Distinct patterns of performance characterized the four disorders. These patterns were consistent with the language deficits typically seen in the disorders, with the exception of a dissociation seen in Williams Syndrome.     

Animal experimentation

Millions of animals are used every year in oftentimes extremely painful and distressing scientific procedures. Legislation of animal experimentation in modern societies is based on the supposition that this is ethically acceptable when certain more or less defined formal (e.g. logistical, technical) demands and ethical principles are met. The main parameters in this context correspond to the “3Rs” concept as defined by Russel and Burch in 1959, i.e. that all efforts to replace, reduce and refine experiments must be undertaken. The licensing of animal experiments normally requires an ethical evaluation process, oftentimes undertaken by ethics committees. The serious problems in putting this idea into practice include inter alia unclear conditions and standards for ethical decisions, insufficient management of experiments undertaken for specific (e.g. regulatory) purposes, and conflicts of interest of ethics committees’ members. There is an ongoing societal debate about ethical issues of animal use in science. Existing EU legislation on animal experimentation for cosmetics testing is an example of both the public will for setting clear limits to animal experiments and the need to further critically examine other fields and aspects of animal experimentation. This paper was presented at the 6th International Bioethics Conference on the subject of ‘The Responsible Conduct of Basic and Clinical Research’, held in Warsaw, Poland, 3–4 June 2005. The paper has been expanded from an article to be published in the forthcoming Council of Europe publication entitled “Animal Protection and Welfare”.     

The Latent Structure of Psychopathy in Youth: A Taxometric Investigation

Using taxometric procedures, the latent structure of psychopathy was investigated in two studies of children and adolescents. Prior studies have identified a taxon (i.e., a natural category) associated with antisocial behavior in adults as well as children and adolescents. However, features of this taxon suggest that it is not psychopathy but rather a broader class consistent with the construct of life course persistent antisocial behavior. Because the only prior study of youth used a non-clinical sample, the base rate of psychopathy may have been too low to reveal a psychopathy taxon, especially against the background of a broader and more prevalent antisocial behavior taxon. Therefore, this investigation sought to increase the likelihood of finding a psychopathy taxon (should one exist) by increasing its expected base rate through inclusion of clinical cases in the samples studied. Results produced evidence for both a broad antisocial behavior problem taxon consistent with past research and a much lower base rate taxon consistent with prevalence expectations for psychopathy. These findings support the existence of latent taxa for both psychopathy and a broader class of antisocial behavior problems. Further taxometric research appears to be warranted, which should use a broader array of indicators, with greater specificity to psychopathy.     

On the property structure of realist collapse interpretations of quantum mechanics and the so-called "counting anomaly"

The aim of this article is twofold. Recently, Lewis has presented an argument, now known as the "counting anomaly", that the spontaneous localization approach to quantum mechanics, suggested by Ghirardi, Rimini, and Weber, implies that arithmetic does not apply to ordinary macroscopic objects. I will take this argument as the starting point for a discussion of the property structure of realist collapse interpretations of quantum mechanics in general. At the end of this I present a proof of the fact that the composition principle, which holds true in standard quantum mechanics, fails in all realist collapse interpretations. On the basis of this result I reconsider the counting anomaly and show that what lies at the heart of the anomaly is the failure to appreciate the peculiarities of the property structure of such interpretations. Once this flaw is uncovered, the anomaly vanishes.     

Measuring study time distributions: Implications for designing computer-based courses

In both traditional lecture-test courses and courses delivered over the World-Wide Web (WWW), both beginning and experienced college students reported studying almost exclusively just before exams. Automatic measures (computer records, WWW page hits, and electronic mail archives) confirmed the self-reported distributions of study times. Weekly deadlines produced weekly volleys of taking on-line quizzes, a pattern that was reflected in self-reports of study times. However, on-line study materials were used primarily for review for regularly scheduled in-class exams. Thus, regardless of course format, students engaged in massed practice and did not experience study aids at appropriate times. Computer technology provides new forms of learning for students, as well as opportunities for instructors to observe patterns of student study time. Management of instructional contingencies will be necessary to bring students into contact with the rich cognitive aids enabled by technology.     

Visibility distances with halogen and conventional headlights

Abstract.— Using visibility distance as a criterion, halogen and conventional continental European high and low-beam headlights were compared in a series of field experiments. On high-beam without opposing light the halogen headlights offered about 25% longer visibility distances than the conventional headlights. With both opposing cars using low-beam there was a slight advantage (<5 m) in favour of halogen headlights. The optimal dipping distance was a function of high-beam system (intensity) rather than low-beam system. Small differences in aiming, atmosphere etc. caused larger differences in visibility distance than did the headlight system.