Perceptual-gestural (mis)mapping in serial short-term memory: The impact of talker variability

The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female–male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this talker variability effect arises from the tendency for perceptual organization to partition the list into streams based on voice such that the representation of order maps poorly onto the formation of a gestural sequence-output plan assembled in support of the reproduction of the true temporal order of the items. In line with the hypothesis, (a) the presence of a spoken lead-in designed to further promote by-voice perceptual partitioning accentuates the effect (Experiments 1 and 2); (b) the impairment is larger the greater the acoustic coherence is between nonadjacent items: Alternating-voice lists are more poorly recalled than four-voice lists (Experiment 3); and (c) talker variability combines nonadditively with phonological similarity, consistent with the view that both variables disrupt sequence output planning (Experiment 4). The results support the view that serial short-term memory performance reflects the action of sequencing processes embodied within general-purpose perceptual input-processing and gestural output-planning systems

Retrieval from memory: Vulnerable or inviolable?

We show that retrieval from semantic memory is vulnerable even to the mere presence of speech. Irrelevant speech impairs semantic fluency—namely, lexical retrieval cued by a semantic category name—but only if it is meaningful (forward speech compared to reversed speech or words compared to nonwords). Moreover, speech related semantically to the retrieval category is more disruptive than unrelated speech. That phonemic fluency—in which participants are cued with the first letter of words they are to report—was not disrupted by the mere presence of meaningful speech, only by speech in a related phonemic category, suggests that distraction is not mediated by executive processing load. The pattern of sensitivity to different properties of sound as a function of the type of retrieval cue is in line with an interference-by-process approach to auditory distraction

The Impact on U.K. Acquirers of Domestic, Cross-border, Public and Private Acquisitions

We examine the announcement and post-acquisition share returns of 4,000 acquisitions by U.K. public firms during 1984-1998. We include acquisitions of domestic and cross-border targets, and of both publicly quoted and privately held targets. In acquisitions of domestic public targets, abnormal returns are negative over both the announcement and post-acquisition period. In acquisitions of cross-border public targets, abnormal returns are zero over the announcement period but negative over the post-acquisition period. In contrast, acquisitions of both domestic and cross-border private targets result in positive announcement returns and zero long run returns. The main difference between private and public acquisitions is that glamour acquirers experience negative announcement and long run returns in public acquisitions, whereas glamour acquirers do not under-perform in private acquisitions. Furthermore, whereas the under-performance of domestic public acquisitions is limited to acquirers using non-cash methods of payment, acquirers of domestic private targets that use non-cash methods do not under-perform. Overall, cross-border acquisitions result in lower announcement and long run returns than domestic acquisitions. In cross-border acquisitions involving high?tech firms both announcement and long run returns are positive, whilst non-high-tech cross-border acquisitions experience zero announcement returns followed by negative long run performance. Our results also suggest that, in cross-border acquisitions, the national cultural difference between the bidder and target countries has a significantly negative impact on long run returns. This paper replaces WP214.Mergers and acquisitions; acquirer share returns; Cross-border targets; private targets

A parametric shell analysis of the shuttle 51-L SRB AFT field joint

Following the Shuttle 51-L accident, an investigation was conducted to determine the cause of the failure. Investigators at the Langley Research Center focused attention on the structural behavior of the field joints with O-ring seals in the steel solid rocket booster (SRB) cases. The shell-of-revolution computer program BOSOR4 was used to model the aft field joint of the solid rocket booster case. The shell model consisted of the SRB wall and joint geometry present during the Shuttle 51-L flight. A parametric study of the joint was performed on the geometry, including joint clearances, contact between the joint components, and on the loads, induced and applied. In addition combinations of geometry and loads were evaluated. The analytical results from the parametric study showed that contact between the joint components was a primary contributor to allowing hot gases to blow by the O-rings. Based upon understanding the original joint behavior, various proposed joint modifications are shown and analyzed in order to provide additional insight and information. Finally, experimental results from a hydro-static pressurization of a test rocket booster case to study joint motion are presented and verified analytically

Analysis of electrical resonance distortion for inductive sensing applications

Resonating inductive sensors are increasingly popular for numerous measurement techniques, not least in non-destructive testing (NDT), due to the increased sensitivity obtained at frequencies approaching electrical resonance. The highly unstable nature of resonance limits the practical application of such methods while no comprehensive understanding exists of the resonance distorting behaviour in relation to typical measurements and environmental factors. In this paper, a study into the frequency spectrum behaviour of electrical resonance is carried out exploring the effect of key factors. These factors, known to distort the electrical resonance of inductive sensors, include proximity to (or lift-off from) a material surface, and the presence of discontinuities in the material surface. Critical features of resonance are used as metrics to evaluate the behaviour of resonance with lift-off and defects. Experimental results are compared to results from a 2D finite element analysis (FEA) model that geometrically mimics the inductive sensor used in the experiments, and to results predicted by an equivalent circuit transformer model. The findings conclusively define the physical phenomenon behind measurement techniques such as near electrical resonance signal enhancement (NERSE), and show that lift-off and defect resonance distortions are unique, measurable and can be equated to exclusive variations in the induced variables in the equivalence circuit model. The resulting understanding found from this investigation is critical to the future development and understanding of a complete model of electrical resonance behaviour, integral for the design of novel sensors, techniques and inversion models