Epaxial and hypaxial co-contraction: a mechanism for modulating strike pressure and accuracy during suction feeding in channel catfish.

Most fish species use concentric epaxial and hypaxial contractions to suction feed, whereby both muscle groups produce cranial expansion and negative intraoral pressures. In contrast, channel catfish (Ictalurus punctatus) suction feed with little to no cranial elevation and epaxial shortening, generating suction power primarily with hypaxial shortening and pectoral girdle retraction. We hypothesized that channel catfish (1) actively anchor the head via isometric contraction of the epaxials and (2) vary feeding performance by modulating the absolute and relative outputs of the co-contracting muscles. We used a combination of electromyography, intraoral pressure recordings and specimen manipulation, and developed a new dual-lever model to explore this idea. We detected epaxial and hypaxial co-contraction prior to suction force development in all strikes. Our model revealed that the differential between the co-contracting muscles may be used to modulate suction pressure and strike accuracy.

Differences in access and utilisation of mental health services in the perinatal period for women from ethnic minorities-a population-based study.

BACKGROUND: Barriers to accessing mental health care during pregnancy and the first postnatal year (perinatal period) seem to be greater for ethnic minority women; however, there is no reliable large-scale data about their actual use of mental health services during this period. Our study aims to explore access rates to secondary mental health services, including involuntary admissions to psychiatric inpatient care and patterns of engagement for ethnic minority women aged 18+ who gave birth in 2017 in England, UK. METHODS: Two datasets from the National Commissioning Data Repository, the Acute Inpatient Dataset and Mental Health Services Dataset, were linked. Datasets covering the full perinatal period for each woman were included. Rates were standardised by age and deprivation. RESULTS: Out of 615,092 women who gave birth in England in 2017, 22,073 (3.5%) started a contact with mental health services during the perinatal period. In total, 713 (3.2%) were admitted to inpatient care, and 282 (39.5%) involuntarily. Ethnicity data was available for 98% of the sample. Black African, Asian and White Other women had significantly lower access to community mental health services and higher percentages of involuntary admissions than White British women. Black African, Asian and White Other women had a higher number of attended community contacts and fewer non-attendances/cancellations of appointments than White British women. CONCLUSION: Access to mental health services during the perinatal period varies significantly between women from different ethnic groups. Access to community mental health services should be facilitated for Black African, Asian and White Other women during the perinatal period, which may reduce rates of involuntary hospital admissions for these groups. The pattern of engagement with community services for women from these ethnicities indicates that access appears to be a problem rather than utilisation.