Low-dimensional chaos maps learning in a model neuropil (olfactory bulb).

Quantification of a chaotic system can be made by calculating the correlation dimension (D2) of the data that the system generates (Packard et al., 1980). The D2 algorithm, however, requires stationarity of the generator, a feature that biological data rarely reflect (Mayer-Kress et al., 1988). So we developed the "point correlation dimension" (PD2), an algorithm that accurately tracks D2 in linked data of different dimensions (Carpeggiani et al., 1991). We now present a mathematical argument that, for stationary data, individual PD2s converge to D2 and we demonstrate that the algorithm rejects contributions made by bursts of noise. Data were obtained from the surface of the olfactory bulb of the conscious rabbit (64 electrodes, 640 Hz each, 1.3 sec epochs) before and after presentation of a novel or habituated odor. D2 could be calculated in only 1 of 10 novel-odor trials, whereas PD2 could be calculated in all. Both algorithms indicated that a novel odor evokes a spatially uniform dimensional increase. The PD2 uniquely exhibited the dimensional decreases that occur during inspiration and the gradients of mean dimension present during the nonstimulated control state. These control gradients remained unchanged without odor experience, but showed spatially specific PD2 increases following odor habituation. It is interpreted that, 1) the PD2 is sensitive, accurate, and appropriate for dimensional assessment of biological data, 2) that during analysis of unfamiliar information a single global process is transiently evoked in the neuropil, and 3) after experience multiple spatially specific processes tonically map the sites of learning.     

Delayed constructed-response identity matching improves the spelling performance of students with mental retardation

We assessed the effects of a computerized matching-to-sample procedure on the spelling performances of three students with mental retardation. Initially, the students could 1) match pictures and printed words to one another, and 2) match pictures and printed words to spoken words. However, they could not construct words to either pictures or spoken words (e.g., touch, in order, the letters s->h->o->e given the spoken-word sample Shoe). Word constructions then improved markedly after exposure to delayed constructed-response identity matching (e.g., touch the letters s->h->o->e given the printed-word sample shoe). One subject's oral and written spelling also improved. The results extend previous research by showing multiple positive effects of a computerized spelling intervention. These effects may have occurred in part because of the formation of stimulus classes among pictures, printed words, and spoken words.     

Parent-tutoring procedures: Experimental analysis and validation of generalization in oral reading across passages,settings, and time

A study that involved parents as reading tutors was carried out at home during the summer with four elementary children, three with learning disabilities. One purpose was to determine the effects of tutoring in the basal reader on reading rates at home. Another purpose was to determine potential generalization effects as a result of parent tutoring on different academic tasks at home and, later at school, on different and similar tasks. A combination multiple-baseline and reversal design tested for replication and generalization effects. Increases in correct rates were noted for the targeted variables across conditions. The results indicated that parents tutoring with school basal texts during the summer produced marked increases in reading rates that generalized at home to different academic tasks and at school to different and similar tasks. This suggests that parents, when using specific tutoring procedures, can increase their children's academic skills.     

Justice and care: The implications of the Kohlberg-Gilligan debate for medical ethics

Carol Gilligan has identified two orientations to moral understanding; the dominant ‘justice orientation’ and the under-valued ‘care orientation’. Based on her discernment of a ‘voice of care’, Gilligan challenges the adequacy of a deontological liberal framework for moral development and moral theory. This paper examines how the orientations of justice and care are played out in medical ethical theory. Specifically, I question whether the medical moral domain is adequately described by the norms of impartiality, universality, and equality that characterize the liberal ideal. My analysis of justice-oriented medical ethics, focuses on the libertarian theory of H.T. Engelhardt and the contractarian theory of R.M. Veatch. I suggest that in the work of E.D. Pellegrino and D.C. Thomasma we find not only a more authentic representation of medical morality but also a project that is compatible with the care orientation's emphasis on human need and responsiveness to particular others.     

Should physicians be Bayesian agents?

Because physicians use scientific inference for the generalizations of individual observations and the application of general knowledge to particular situations, the Bayesian probability solution to the problem of induction has been proposed and frequently utilized. Several problems with the Bayesian approach are introduced and discussed. These include: subjectivity, the favoring of a weak hypothesis, the problem of the false hypothesis, the old evidence/new theory problem and the observation that physicians are not currently Bayesians. To the complaint that the prior probability is subjective, Bayesians reply that there will be ultimate convergence, but the rebuttal to this is that there will not be uniform convergence. Secondly, since the Bayesian scheme favors a weak hypothesis, theories turn out to be a gratuitous risk. The problem with the false hypothesis comes out in the denominator of the theorem, revealing that a factor which is not a theory at all is being considered in the reasoning. On the old evidence/new theory problem old evidence cannot confirm a new theory so that the posterior probability will equal the prior probability. Finally, empiric studies have shown that current physicians are not Bayesians. But on consideration of Bayesian inference as a system of inference, it can be reasoned that physicians should be Bayesians. However, the problem of physicians' and patients' own subjectivity continue to plague this system of medical decision making.     

Genetics and adoption: Forming a partnership

Genetic issues are demanding more attention in the area of public health. Adoption agencies and policymakers are beginning to address these issues where they relate to the adoption process and to the many families involved in adoption in this country. Genetic counselors need to play an active role as both educators of and consultants for adoption professionals and the families with whom they work. To facilitate a partnership between genetics and adoption we have developed a workshop intended to educate adoption professionals about the lifelong implications of genetic conditions on the adoption triad.     

Developmental sequences in the age of onset of disruptive child behaviors

Retrospective and prospective reports of the onset of disruptive child behaviors were analyzed in a sample of clinic-referred boys. The younger boys (ages 7–9 years), compared with the older boys (ages 10–12 years), showed the highest level of disruptive behavior and, judging from mothers' reports, had the fastest progression of onsets from less serious to more serious problem behaviors. Despite some overlap, developmental sequences in problem behavior within the domains of hyperactivity/inattention, oppositional behavior, and conduct problems were similar across the two age groups. This was also the case for developmental sequences of overt or confrontive problem behaviors and covert or concealing conduct problems. Sequences of the onset of oppositional behavior and conduct problems were validated through prospective data, based on the information from mothers, teachers, and boys themselves. The implications of the findings are discussed for the formulation of developmental pathways of behavior and the analysis of causal factors.