No abstract

Six experiments are reported which examine the assertion that phonological recoding for the purpose of lexical access in visual word recognition is prevented or impaired by concurrent articulation ("articulatory suppression"). The first section of this paper selectively reviews the literature, and reports two experiments which fail to replicate previous work.The third experiment contrasts performance with visually presented words and with non-words. Latency measures show an effect of suppression that is specific to words, whilst error rates show an effect common to both words and non-words.The fourth experiment shows that if the task is changed from a judgement of rhyme (BLAME-FLAME) to one of homophony (AIL-ALE), the suppression effect seen in the latency data is eliminated, whilst error effects remain. It is suggested that, in addition to producing error effects that are not easily interpretable, suppression prevents or impairs a phonological segmentation process operating subsequent to the retrieval of whole word phonology (a process that is needed for rhyme judgement but not for one of homophony).Experiment V shows that while suppression has no effect on the time taken to decide if printed non-words sound like real words (e.g. PALLIS), error rates increase. Experiment VI shows that suppression has no effect on either R T or errors in the same task if subjects suppress at a slower rate than in Experiment V. Buffer storage and/or maintenance of phonologically coded information derived from print is affected by suppression; phonological recoding from print for the purpose of lexical access can be carried out without any interference from suppression.It is suggested that there are at least two different phonological codes.

Centre f o r the Study of Management Learning, University of Lancaster Addrerrfor reprints: Mrs. J. Davies/Ilr. M. Easterby-Smith, Centre for the Study of Management Learning, Gillow House, University of Lancaster, Lancaster LA1 4YX. J U L I A D A V I E S A N D M A R K

Results are presented from the first underground data run of ZEPLIN-II, a 31 kg two-phase xenon detector developed to observe nuclear recoils from hypothetical weakly interacting massive dark matter particles. Discrimination between nuclear recoils and background electron recoils is afforded by recording both the scintillation and ionisation signals generated within the liquid xenon, with the ratio of these signals being different for the two classes of event. This ratio is calibrated for different incident species using an AmBe neutron source and 60Co γ-ray sources. From our first 31 live days of running ZEPLIN-II, the total exposure following the application of fiducial and stability cuts was 225 kg × days. A background population of radon progeny events was observed in this run, arising from radon emission in the gas purification getters, due to radon daughter ion decays on the surfaces of the walls of the chamber. An acceptance window, defined by the neutron calibration data, of 50% nuclear recoil acceptance between 5 keVee and 20 keVee, had an observed count of 29 events, with a summed expectation of 28.6 ± 4.3 γ-ray and radon progeny induced background events. These figures provide a 90% c.l. upper limit to the number of nuclear recoils of 10.4 events in this acceptance window, which converts to a WIMP nucleon spin-independent cross-section with a minimum of 6.6 × 10-7 pb following the inclusion of an energy-dependent, calibrated, efficiency. A second run is currently underway in which the radon progeny will be eliminated, thereby removing the background population, with a projected sensitivity of 2 × 10-7 pb for similar exposures as the first run