This paper reviews concepts of depression, including history and classification. The original broad concept of melancholia included all forms of quiet insanity. The term depression began to appear in the nineteenth century, as did the modern concept of affective disorders, with the core disturbance now viewed as one of mood. The 1980s saw the introduction of defined criteria into official diagn...

Given this inherent complexity, the text is remarkably well integrated and presents a balanced picture of current knowledge and questions. As in any book written by many authors, the style and quality of chapters vary, but the overall quality of writing is very good. The chapters by Milton Hildebrand ("Walking and Running"), James L. Edwards ("Terrestrial Locomotion Without Appendages"), and Jo...

This article presents the basic place/transition net structure definition for building various types of Petri nets. The basic net structure fields include places, transitions, and arcs (place-transition, transition-place) which may be supplemented with other fields (e.g., capacity, weight, marking, etc.) as needed. The theorems included in this article are divided into the following categories:...