A logical expression of reasoning

A non-monotonic logic, the Logic of Plausible Reasoning (LPR), capable of coping with the demands of what we call complex reasoning, is introduced. It is argued that creative complex reasoning is the way of reasoning required in many instances of scientific thought, professional practice and common life decision taking. For managing the simultaneous consideration of multiple scenarios inherent in these activities, two new modalities, weak and strong plausibility, are introduced as part of the Logic of Plausible Deduction (LPD), a deductive logic specially designed to serve as the monotonic support for LPR. Axiomatics and semantics for LPD, together with a completeness proof, are provided. Once LPD has been given, LPR may be defined via a concept of extension over LPD. Although the construction of LPR extensions is first presented in standard style, for the sake of comparison with existing non-monotonic formalisms, alternative more elegant and intuitive ways for constructing non-monotonic LPR extensions are also given and proofs of their equivalence are presented.     

Sex differences in response to the odor of alpha androstenone

Additional analyses of ratings by 98 male and 102 female college students assigned to one of four odor conditions showed no significant correlations for the methyl anthranilate or skatole odor conditions, but the pattern of correlations for men and women was different in the alpha androstenone condition, e.g., if men found alpha androstenone pleasant they tended to rate the target male positively.     

Compensatory neoplasia: Chronic erythrocytosis and neuroblastic tumors

There are a large number of exogenous biological and chemical substances with known neoplastic or carcinogenic potential. However, it has also been postulated that external stimuli can influence the body's internal milieu, and thereby induce compensatory excessive growth of cells in the form of hyperplasia or neoplasia. In a recent study, we observed a strong association between chronic hypoxic states and the occurrence of peripheral neuroblastic tumors, a relatively uncommon group of neural neoplasms. In this report we review those findings and formulate an hypothesis to explain why conditions which lead to chronic erythrocytosis may also cause compensatory neoplasia of neural tissues.     

ERL—A language for implementing evoked response and psychophysiological experiments

Evoked Response Language (ERL) is a high-level language for implementing psychophysiological experiments with emphasis on signal averaging techniques. It allows the E to specify, in English-like statements, a sequence of auditory and visual stimuli and to collect or average associated physiological data. The language can be learned quickly without the need for knowledge of machine language programming. Programs can be easily composed and promptly tested. ERL has been running in our laboratory on a classic LINC computer since the spring of 1970. Expanded versions of ERL are being planned for the PDP-12 and SEL 810B computers.     

Data acquisition system for precision eye-fixation studies

A system has been developed to sense and record eye point-of-gaze for on-line computer processing, using a Mackworth camera in conjunction with a closed-circuit television system. System optics and electronics are described, together with computer software for system calibration and automatic artifact removal.     

A reasoning method for a paraconsistent logic

A proof method for automation of reasoning in a paraconsistent logic, the calculus C1* of da Costa, is presented. The method is analytical, using a specially designed tableau system. Actually two tableau systems were created. A first one, with a small number of rules in order to be mathematically convenient, is used to prove the soundness and the completeness of the method. The other one, which is equivalent to the former, is a system of derived rules designed to enhance computational efficiency. A prototype based on this second system was effectively implemented.     

Progressive catatonia

We present the case of a young man with a diagnosis of a childhood-onset pervasive developmental disorder who developed a progressive neurologic deterioration with persistent catatonia and right hemiparesis. On his initial evaluation approximately three years after the onset of mutism, he manifested right hemiparesis and catalepsy. Two years later, although catalepsy had subsided, motor function had deteriorated so that he could not use his hands to feed or dress himself. Oral-facialbuccal dyskinesia manifested by blepharospasm and grimacing were present constantly during waking hours. Quantitative electroencephalography demonstrated markedly decreased amplitude, a finding associated with catatonia. Left sural nerve biopsy indicated large axon cylinder degeneration. Left deltoid biopsy demonstrated perimysial fibrosis and type II fiber predominance. Although magnetic resonance imaging of the head without contrast was normal, positron emission tomography indicated hypometabolism of the right cerebral and the right cerebellar hemispheres. The patient continues to deteriorate despite a course of 25 electroconvulsive treatments. He continues to manifest criteria for catatonia including motoric immobility, mutism, and peculiarities of voluntary movement such as prominent grimacing. We suspect an inherited neurodegenerative disorder. Since catatonia is a treatable condition frequently associated with medical and neurological diseases, examination for the features of catatonia must be included in the assessment of patients with progressive brain degeneration. This report is an attempt to clarify the traits of a serious variant of progressive brain degeneration.