A perfectly matched layer (PML) absorbing material composed of a uniaxial anisotropic material is presented for the truncation of finite-difference time-domain (FDTD) lattices. It is shown that the uniaxial PML material formulation is mathematically equivalent to the perfectly matched layer method published by Berenger (see J. Computat. Phys., Oct. 1994). However, unlike Berenger's technique, the uniaxial PML absorbing medium presented in this paper is based on a Maxwellian formulation. Numerical examples demonstrate that the FDTD implementation of the uniaxial PML medium (...) is stable, equal in effectiveness as compared to Berenger's PML medium, while being more computationally efficient. (shrink)

Historically, the hypothesis driving emotion research has been that emotion’s data-base—in language, physiology, and behavior— is organized around specific mental states, as reflected in evaluative language. It is suggested that this approach has not greatly advanced a natural science of emotion and that the developing motivational model of emotion defines a better path: emotion is an evolved trait founded on motivational neural circuitry shared by mammalian species, primitively prompting heightened perceptual processing and reflex mobilization for action to appetitive or threatening (...) survival cues. As the field moves forward with increasingly sophisticated measurement technology and assessing more complex affective functioning, scientific understanding of human emotion will proceed best within the framework of this mammalian brain model. (shrink)

'Fear' is used scientifically in two ways, which causes confusion: it refers to conscious feelings and to behavioral and physiological responses. Restricting the use of 'fear' to denote feelings and using 'threat-induced defensive reactions' for the responses would help avoid misunderstandings about the brain mechanisms involved.

A scientific community cannot practice its trade without some set of received beliefs. These beliefs form the foundation of the "educational initiation that prepares and licenses the student for professional practice". The nature of the "rigorous and rigid" preparation helps ensure that the received beliefs are firmly fixed in the student's mind. Scientists take great pains to defend the assumption that scientists know what the world is like...To this end, "normal science" will often suppress novelties which undermine its foundations. Research (...) is therefore not about discovering the unknown, but rather "a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education". (shrink)

Thomas S. Kuhn's classic book is now available with a new index.

This first volume contains discussions of the brain, methods for analyzing behavior, thought, consciousness, attention, association, time, and memory.

To make progress on the problem of consciousness, we have to confront it directly. In this paper, I first isolate the truly hard part of the problem, separating it from more tractable parts and giving an account of why it is so difficult to explain. I critique some recent work that uses reductive methods to address consciousness, and argue that such methods inevitably fail to come to grips with the hardest part of the problem. Once this failure is recognized, the (...) door to further progress is opened. In the second half of the paper, I argue that if we move to a new kind of nonreductive explanation, a naturalistic account of consciousness can be given. I put forward my own candidate for such an account: a nonreductive theory based on principles of structural coherence and organizational invariance, and a double-aspect theory of information. (shrink)