Competition-Based Induction of Decision Models from Examples

Symbolic induction is a promising approach to constructing decision models by extracting regularities from a data set of examples. The predominant type of model is a classification rule (or set of rules) that maps a set of relevant environmental features into specific categories or values. Classifying loan risk based on borrower profiles, consumer choice from purchase data, or supply levels based on operating conditions are all examples of this type of model-building task. Although current inductive approaches, such as ID3 and CN2, perform well on certain problems, their potential is limited by the incremental nature of their search. Genetic algorithms (GA) have shown great promise on complex search domains, and hence suggest a means for overcoming these limitations. However, effective use of genetic search in this context requires a framework that promotes the fundamental model-building objectives of predictive accuracy and model simplicity. In this article we describe COGIN, a GA-based inductive system that exploits the conventions of induction from examples to provide this framework. The novelty of COGIN lies in its use of training set coverage to simultaneously promote competition in various classification niches within the model and constrain overall model complexity. Experimental comparisons with NewID and CN2 provide evidence of the effectiveness of the COGIN framework and the viability of the GA approach.     

Effect of cigarette smoking on duodenogastric reflux of bile acids

The possibility that smoking induces duodenogastric reflux was examined in 13 healthy male volunteers. Gastric juice was aspirated for four consecutive 20-minute periods, and reflux quantitated by measuring total bile acids (TBA), chenodeoxycholic acid (CDCA) and glycocholic acid (GCA) in the juice. One cigarette was smoked during either period 2 or period 3. Amounts of bile acids (mumoles: means +/- SEM) refluxing into stomach during the pre-smoking, smoking, and post-smoking periods respectively were: TBA-4.5 +/- 1.1, 5.4 +/- 3.0 and 3.9 +/- 1.6, CDCA-1.7 +/- 0.6, 1.5 +/- 0.9 and 2.0 +/- 1.1; GCA-1.8 +/- 1.1, 1.1 +/- 0.6 and 1.0 +/- 0.6. Paired analysis revealed no significant effect of smoking on any of these parameters. These findings, based on quantitative methods, do not confirm those of previous unblinded and semiquantitative studies. We conclude that smoking one cigarette does not provoke duodenogastric reflux.     

Surface impedance measurements of cuprate superconductors: Nd1.85.85Ce0.15CuO4−δ —A case study

We present results on the temperature dependence of the surface impedance of high-quality thin films and single crystals of the electron-doped Nd_1.85Ce_0.15CuO_4?δ cuprate superconductor. Surprisingly, these measurements are consistent with the behavior of ans-wave BCS superconductor. We also briefly review some highlights of surface impedance measurements on hole-doped cuprate superconductors, and contrast those with the results on Nd,_1.85Ce_0.15CuO_4?δ.     

The relationship of perceived self-efficacy to quality of life in chronic obstructive pulmonary disease.

From a biomedical perspective, variations in the quality of life of chronic obstructive pulmonary disease (COPD) patients may be attributed to changes in pulmonary function, thus, an increase in lung function should be correlated with an increased score on a health-related quality-of-life measure. However, inconsistent results regarding correlations between various measures of pulmonary function and quality of life have been reported in the literature. The authors evaluated a social cognitive model of quality of life among persons with COPD by analyzing relationships among biomedical measures, self-efficacy measures, and quality-of-life measures in a recursive path model. Path analysis results indicated that the association of pulmonary function and symptoms with quality of life was mediated by perceived self-efficacy for functional activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterned (single) alternation in infant rats after combined or separate lesions of hippocampus and amygdala.

The role of the developing hippocampus and the amygdala on patterned (single) alternation (PA) in the infant rat was investigated in 4 experiments. In Exps 1 and 2, Ss were given 2 bilateral electrolytic hippocampal lesions or sham surgeries at 10 or 11 days of age and were trained 6 days later in a straight runway. In Exp 1, there were 120 trials in 1 day, with an 8-, a 15-, or a 30-s intertrial interval (ITI). PA learning occurred in lesion and sham Ss at the 8- and 15-s ITIs. In Exp 2, training was extended to 240 trials over 2 days, with a 30- or 60-s ITI. Sham and lesion Ss showed PA at the 30-s ITI, but the emergence of PA was delayed in the lesion pups at the 60-s ITI. In Exp 3, amygdaloid lesions had no effect on PA learning at the 8-s ITI. However, when Ss with hippocampal and amygdaloid lesions were trained at the 8-s ITI, the emergence of PA was delayed, and its size was reduced (Exp 4). Results argue for a role of the hippocampus in PA learning at long ITIs and suggest that, even in 16-day-old Ss exposed to an 8-s ITI, the combined hippocampal and amygdaloid lesion produces a deficit greater than either the hippocampal or the amygdaloid lesion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can clients provide valuable feedback to clinicians about their personality interpretations? Greene replies.

Maintains that the criticisms of C. R. Snyder et al (see record 1979-26547-001) in response to the present author's (see record 1978-01956-001) study (1977) overlooked several significant issues that are important in reconceptualizing research on students' acceptance of generalized personality interpretations. These issues are stated explicitly, and their relevance to research in this area is described. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adenosine inhibition of mesopontine cholinergic neurons: implications for EEG arousal

Increased discharge activity of mesopontine cholinergic neurons participates in the production of electroencephalographic (EEG) arousal; such arousal diminishes as a function of the duration of prior wakefulness or of brain hyperthermia. Whole-cell and extracellular recordings in a brainstem slice show that mesopontine cholinergic neurons are under the tonic inhibitory control of endogenous adenosine, a neuromodulator released during brain metabolism. This inhibitory tone is mediated postsynaptically by an inwardly rectifying potassium conductance and by an inhibition of the hyperpolarization-activated current. These data provide a coupling mechanism linking neuronal control of EEG arousal with the effects of prior wakefulness, brain hyperthermia, and the use of the adenosine receptor blockers caffeine and theophylline.