Biomedical subjects
Publications and source records attributed to J Morais.
In a multiple-target single-probe experiment on auditory memory, evidence was obtained for two different strategies off search, one being more efficient than the other both in terms of accuracy and rapidity. The result urges us to be cautious in the interpretation of experiments in which a large number of subjects low in accuracy are discarded in the screening phase.
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Contrasting with previous reports, left-ear advantage was found for recognition of chords by non-musicians (n = 16). It is suggested that the less memory is involved the more the effect may appear in musically naive subjects.
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Two synthetic speech syllables, differing in pitch, were presented over one loudspeaker situated at one of the following azimuths: 0 degrees (in from of the subject); 45 degrees, 90 degrees, and 135 degrees to the left or to the right; and 180 degrees. The subject's task was to report the high-pitch syllable. The pattern of performance can be described in terms of two component effects: a decreasing anterior-posterior gradient, and right-side advantage. Competition between messages from one direction only appears to be as effective in determining auditory spatial effects as competition between spatially distinct sources.
The subjects listened to one of two simulataneous synthetic speech syllables delivered independently over two loudspeakers. When the loudspeakers were situated at 90 degrees to the left and to the right, right-side advantage was found. When one loudspeaker was situated in front of the subject in the median plane, and the other at one of several azimuthal positions around him an advantage of the frontal position was observed in all cases. On the other hand, performance on the nonfrontal message was affected significantly by its position. The pattern of performance which is presumably to cerebral dominance, an advantage of sources situated in front of the subject over those at his back, and possibly an advantage of sources near the median plane over more remote ones.
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The study concerned discriminating between ear of entry and apparent spatial position as possible determinants of lateral asymmetries in the recall of simultaneous speech messages. Apparent localization to the left or right of the median plane was created either through a time difference (.7 msec), through intensity differences between presentations of the same verbal message at the two ears, or through dichotic presentations. Right-side advantage was observed with the three types of presentation (Experiments 1, 2, and 3). The finding of right-side advantage with stereophony based on a time difference only, in the absence of intensity difference, cannot be accounted for in terms of an ear advantage and shows that apparent spatial separation of the sources can by itself produce a laterality effect. Differences in the degree of lateral asymmetry between the various conditions were also observed. The findings of Experiments 4 and 5 suggest that these differences are better explained in terms of different impressions of localization of the sound sources than in terms of relative intensity at the "privileged" ear.
Morais and Darwin's (1974) finding of a right-ear advantage for speech on a "same-different" reaction-time task under monaural stimulation was replicated with 8 Ss who knew before each block of trials which ear would be stimulated. The effect cannot be accounted for in terms of a lateral bias in voluntary attention.
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The necessity of a "levels-of-processing" approach in the study of mental representations is illustrated by the work on the psychological reality of the phoneme. On the basis of both experimental studies of human behavior and functional imaging data, it is argued that there are unconscious representations of phonemes in addition to conscious ones. These two sets of mental representations are functionally distinct: the former intervene in speech perception and (presumably) production; the latter are developed in the context of learning alphabetic literacy for both reading and writing purposes. Moreover, among phonological units and properties, phonemes may be the only ones to present a neural dissociation at the macro-anatomic level. Finally, it is argued that even if the representations used in speech perception and those used in assembling and in conscious operations are distinct, they may entertain dependency relations.
Ab initio molecular orbital calculations at the STO-3G and 3-21G levels were used to clarify the mechanism of mutagenic action of various substituted allyl chlorides. Computed molecular properties were compared with experimental mutagenic potentials of these allylic compounds. In agreement with experiment, the computational results suggest that the primary mechanism of action involves the SN1 formation of allylic cations which then react with nucleophilic centers of nucleic acid bases. The usefulness of computed properties in estimating the degree of alkylating activity and mutagenicity was evaluated. In general, stability of the allylic carbocation intermediate and the degree of charge delocalization in the allyl system correlate well with observed mutagenic potentials.
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UNLABELLED: The management of acute myocardial infarction (AMI) has improved markedly over the last decade. Large-scale trials have produced a large amount of evidence, and recommendations and guidelines have been established. Whether and to what extent these data have influenced everyday practice on a nationwide scale remains to be ascertained. The present observational prospective, registry was designed to assess current practice in in-hospital management of AMI in Portugal. For a period of 3 months (February to May, 1999), 44 centers, distributed all over the country, Atlantic islands included, enrolled 1372 cases of AMI corresponding to 1366 patients (996 male, mean age 65 +/- 13 years; 370 female, mean age 72 + 11 years; p < 0.0001). Non-ST segment elevation infarcts were present in 26% of cases. In-hospital mortality was 11.2% (154 pts, mean age 74 +/- 10 years). RESULTS: 519 pts (37.8%) were managed with reperfusion therapy, 413 of them with fibrinolysis (30.1%) and 106 with primary PTCA (7.7%). Besides the invasive procedures performed within the first few hours after admission, coronary angiography was performed in 327 more pts (26.1%); 143 pts were revascularized (PTCA in 117 pts and CABG in 26) and 96 more pts were discharged and referred for further revascularization. The total number of pts given or referred for a revascularization procedure (including the primary treatment) was 316 (20.6%). Besides reperfusion therapy the most commonly used drugs for secondary prevention were aspirin in 91%; ACE inhibitors in 63%; beta-blockers in 45%; and statins in 28%. Based on the results of this nationwide survey it can be concluded that the main international guidelines and recommendations for the medical management of acute myocardial infarction are generally being applied in Portugal.
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