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BACKGROUND: South Africa's maternal mortality ratio has increased from 150/100 000 in 1990 to 269/100 000 live births in 2015 against the Millennium Development Goals 5 (MDG5) target of 38/100 000, indicating slow progress in improving maternal health. The neonatal mortality rate was 14/1000 live births against the MDG4 target of 7/1000. The purpose of the article was to outline the socio-economic factors that determine maternal and neonatal mortality in South African communities. OBJECTIVES: To identify and describe the social determinants of maternal and neonatal mortality in South Africa. METHOD: A qualitative study using audio-taped individual interviews was conducted. The interviews included 10 pregnant women who were purposefully recruited from the antenatal clinic attendees in a public hospital. The interviews were conducted in isiZulu and later translated into English by the researcher who is fluent in both. Data were analysed using the World Health Organization's (WHO) Commission on Social Determinants of Health framework. RESULTS: Findings revealed that poverty was an underlying factor to the vulnerability to illness and death of the mothers and their neonates. Other determinants were found to be the nutritional inadequacies, neglect and abuse by male partners, HIV or AIDS, inattention to reproductive health and violation of reproductive rights, and powerlessness of women and health system issues such as poor quality and incompetent health care. CONCLUSION: It is apparent that poverty plays a major role in determining the health of mothers and neonates. This requires more coordinated multi-sectorial interventions to address both the social determinants and direct causes of maternal and neonatal deaths.

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Conductive hearing loss produced by middle ear disease (MED) is very prevalent in the first 5 years of childhood. Both MED in children and prolonged ear plugging in animals lead to a binaural hearing impairment that persists beyond the duration of the peripheral impairment. However, after cessation of the MED, or removal of the ear plug, binaural hearing gradually improves. We suggest here that this improvement is a passive form of auditory learning. We also show that active auditory learning, through repetition of discrimination tasks, can accelerate performance increments, both after hearing loss and in unimpaired individuals. A more detailed understanding of auditory learning holds out the prospect of improving rehabilitation strategies for the language- and hearing-impaired.

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The BreastScreen Queensland Brisbane Southside BreastScreen Service reports on a study of 10 cases of bilateral breast carcinomas from a total cancer population of 217 cases. All cases were patients of screening examinations that were recalled for a suspicious lesion in one breast. Two cases were mammographically suspicious of bilateral tumours. In eight cases, tumours were ultrasonically visible in both breasts and in two further cases, the suspicion of bilateral malignancy was raised by the presence of bilateral microcalcification. It is not the purpose of this paper to provide a statistical analysis of the occurrence of bilateral breast cancer. This is a radiological paper from a breast screening service reporting on findings that conventional wisdom may find unusual. The incidence of bilateral breast malignancy in the study was found to be somewhat higher than expected. These cases have been diagnosed by the utilization of a particularly high standard of ultrasound and mammography, performed and interpreted by diagnosticians possessing an elevated level of suspicion of the possible presence of a second primary lesion. It is therefore proposed that an increased rate of diagnosis of bilateral tumours is possible with an evolution of assessment protocols, combined with quality ultrasound and mammography.

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This study examined the effect of center frequency and level on the perceptual grouping of rapid tone sequences. The sequence ABA-ABA-...was used, where A and B represent sinusoidal tone bursts (10-ms rise/fall, 80-ms steady state, 20-ms interval between tones) and - represents a silent interval of 120 ms. In experiment 1, tone A was fixed in frequency at 62, 125, 250, 500, 1000, 2000, 4000, 6000, or 8000 Hz. Both tones had a level of approximately 40 dB SL. Tone B started with a frequency well above that of tone A, and its frequency was swept toward that of tone A so that the frequency separation between them decreased in an exponential manner. Subjects were required to indicate when they could no longer hear the tones A and B as two separate streams, but heard only a single stream with a "gallop" rhythm. This changeover point between percepts is called the fission boundary. The separation between tones A and B at the fission boundary was roughly independent of the frequency of tone A when expressed as the difference in number of equivalent rectangular bandwidths (ERBs) between A and B, but varied more with frequency when the difference was expressed in barks or cents. In experiment 2, the center frequency was fixed at 250, 1000, or 4000 Hz, and the level of the A and B tones was 40, 55, 70, or 85 dB SPL. The frequency separation of the A and B tones at the fission boundary tended to increase slightly with increasing level, in a manner consistent with the broadening of the auditory filter with increasing level. The results support the "peripheral channeling" explanation of stream segregation advanced by Hartmann and Johnson [Music Percept. 9, 155-184 (1991)], and indicate that the perception of fusion or fission in alternating-tone sequences depends partly upon the degree of overlap of the excitation patterns evoked by the successive sounds in the cochlea, as assumed in the theory of Beauvois and Meddis [J. Acoust. Soc. Am. 99, 2270-2280 (1996)].

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This study examined the perceptual grouping of rapid tone sequences for listeners with normal hearing and listeners with unilateral and bilateral cochlear hearing loss. The sequence ABA-ABA- was used, where A and B represent sinusoidal tones bursts (10-ms rise/fall, 80-ms steady state, 20-ms interval between tones) and - represents a silent interval of 120 ms. Tone A was fixed in frequency at 250, 500, 1000, or 2000 Hz. Tone B started with a frequency well above or below that of tone A, and its frequency was swept towards that of tone A so that the frequency separation between them decreased in an exponential manner. Listeners were required to indicate when they could no longer hear the tones A and B as two separate streams, but heard only a single stream with a "gallop" rhythm. This is called the fission boundary. For the normally hearing listeners, the separation between tones A and B at the fission boundary was roughly independent of the frequency of tone A when expressed as the difference in number of ERBs (delta E) between A and B, which is consistent with a recent model of stream segregation [M. W. Beauvois and R. Meddis, J. Acoust. Soc. Am. 99, 2270-2280 (1996)]. For the unilaterally hearing-impaired listeners, there was no consistent difference in the delta E magnitudes across ears, even though the auditory filters were broader in the impaired ears. This is not consistent with the theory of Beauvois and Meddis. The bilaterally hearing-impaired listeners sometimes showed delta E magnitudes within the normal range, and sometimes showed larger than normal delta E magnitudes. The results are discussed in terms of the factors that might influence perceptual stream formation in hearing-impaired listeners.

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