Calculation of the phonon dispersion curves for b.c.c. transition metals using the Finnis-Sinclair potentials

Abstract

The phonon dispersion curves for body-centred cubic transition metals are calculated using Finnis-Sinclair potentials. The accuracy of results obtained for metals of the VIa and Va groups is commented on.     

Dissociation of mechanisms involved in dogs' oriented displacements

Factors determining spatial choice were studied in experiments conducted outdoors. Six dogs (Breton spaniel) had to choose between two paths leading to a baited feeding bowl (goal). Transparent or opaque screens were interposed between the starting-point and the goal; their arrangement was devised so as to control the length and the angular deviation or divergence of the paths. The results show that when the goal was visible (transparent screens) dogs preferred the less divergent path indicating that angular deviation was the most relevant variable. When the goal was hidden (opaque screen), they preferred the shorter path and did not take into account the angular deviation. These results suggest that two classes of mechanism underlie the selection of path in these spatial situations.     

c.e.的Wtt-度中的下确界(英文)

本文研究了Wtt-度区间的下确界的的存在性问题。我们先证明了Wtt-度中区间对无下确界的向上稠密性。接着我们证明了存在c.e.度a,b(ba)使得对于X∈[0,b],X与A形成Wtt-度中的极小度。     

The detectability of local and global displacements in regular rhythmic patterns

Summary The aim of this study is to find out by which mechanism human subjects discriminate a regular sequence of beats from an irregular one. Therefore a detection experiment was conducted in which subjects had to detect one of three different types of displacement within a regular rhythmic pattern. The results are against a theory which assumes that in such a task successive intervals are compared. They are more in favor of a theory that postulates an internal time keeper which is synchronized with the presented pattern.     

Object permanence in cats (Felis catus): an ecological approach to the study of invisible displacements.

A single invisible displacement object permanence task was administered to 19 cats (Felis catus). In this task, cats watched a target object from behind a transparent panel. However, cats had to walk around an opaque panel to reach the object. While cats were behind the opaque panel, the object was hidden behind one of two screens. As cats did not perceive the disappearance of the object behind the target screen, the object was invisibly hidden. Results showed that cats solved this task with great flexibility, which markedly contrasts with what has been observed in previous research. The discussion emphasizes the difference between the typical Piagetian task in which the information necessary to succeed must be dealt with in retrospective way, whereas in our task cats had to anticipate a new position of the object. The ecological relevance of this new task is also discussed.     

Representational momentum and related displacements in spatial memory: A review of the findings

Memory for the final location of a moving target is often displaced in the direction of target motion, and this has been referred to asrepresentational momentum. Characteristics of the target (e.g., velocity, size, direction, and identity), display (e.g., target format, retention interval, and response method), context (landmarks, expectations, and attribution of motion source), and observer (e.g., allocation of attention, eye movements, and psychopathology) that influence the direction and magnitude of displacement are reviewed. Specific conclusions regarding numerous variables that influence displacement (e.g., presence of landmarks or surrounding context), as well as broad-based conclusions regarding displacement in general (e.g., displacement does not reflect objective physical principles, may reflect aspects of naive physics, does not solely reflect eye movements, may involve some modular processing, and reflects high-level processes) are drawn. A possible computational theory of displacement is suggested in which displacement (1) helps bridge the gap between perception and action and (2) plays a critical part in localizing stimuli in the environment.