Study of the exchange anisotropy in the quantum chain systems (C\u3csub\u3e6\u3c/sub\u3eH\u3csub\u3e11\u3c/sub\u3eNH\u3csub\u3e3\u3c/sub\u3e)CuCl\u3csub\u3e3\u3c/sub\u3e and (C\u3csub\u3e6\u3c/sub\u3eH\u3csub\u3e11\u3c/sub\u3eNH\u3csub\u3e3\u3c/sub\u3e)CuBr\u3csub\u3e3\u3c/sub\u3e by means of (anti) ferromagnetic resonance

\u3cp\u3eFerromagnetic resonance (FMR) measurements on the magnetic quasi-one-dimensional systems (C\u3csub\u3e6\u3c/sub\u3eH\u3csub\u3e11\u3c/sub\u3eNH\u3csub\u3e3\u3c/sub\u3e) CuCl\u3csub\u3e3\u3c/sub\u3e (CHAC) and (C\u3csub\u3e6\u3c/sub\u3eH\u3csub\u3e11\u3c/sub\u3eNH\u3csub\u3e3\u3c/sub\u3e)CuBr \u3csub\u3e3\u3c/sub\u3e (CHAB) in the region 8< nu <75 GHz and at a temperature of 1.25K are presented. The experimental results can be described quite well by a classical mean-field model assuming that, in a first approximation, the ferromagnetic chains behave like independent entities. A comparison of this model with the experimental results yields accurate values for the exchange anisotropy. These values indicate a pronounced easy-plan anisotropy for CHAB, whereas for CHAC the inferred anisotropy is clearly orthorhombic. These results are in fair agreement with previously reported measurements of magnetisation and specific heat.\u3c/p\u3

Maternal and neonatal outcomes after caesarean delivery in the African Surgical Outcomes Study: a 7-day prospective observational cohort study.

BACKGROUND: Maternal and neonatal mortality is high in Africa, but few large, prospective studies have been done to investigate the risk factors associated with these poor maternal and neonatal outcomes. METHODS: A 7-day, international, prospective, observational cohort study was done in patients having caesarean delivery in 183 hospitals across 22 countries in Africa. The inclusion criteria were all consecutive patients (aged ≥18 years) admitted to participating centres having elective and non-elective caesarean delivery during the 7-day study cohort period. To ensure a representative sample, each hospital had to provide data for 90% of the eligible patients during the recruitment week. The primary outcome was in-hospital maternal mortality and complications, which were assessed by local investigators. The study was registered on the South African National Health Research Database, number KZ_2015RP7_22, and on ClinicalTrials.gov, number NCT03044899. FINDINGS: Between February, 2016, and May, 2016, 3792 patients were recruited from hospitals across Africa. 3685 were included in the postoperative complications analysis (107 missing data) and 3684 were included in the maternal mortality analysis (108 missing data). These hospitals had a combined number of specialist surgeons, obstetricians, and anaesthetists totalling 0·7 per 100 000 population (IQR 0·2-2·0). Maternal mortality was 20 (0·5%) of 3684 patients (95% CI 0·3-0·8). Complications occurred in 633 (17·4%) of 3636 mothers (16·2-18·6), which were predominantly severe intraoperative and postoperative bleeding (136 [3·8%] of 3612 mothers). Maternal mortality was independently associated with a preoperative presentation of placenta praevia, placental abruption, ruptured uterus, antepartum haemorrhage (odds ratio 4·47 [95% CI 1·46-13·65]), and perioperative severe obstetric haemorrhage (5·87 [1·99-17·34]) or anaesthesia complications (11·47 (1·20-109·20]). Neonatal mortality was 153 (4·4%) of 3506 infants (95% CI 3·7-5·0). INTERPRETATION: Maternal mortality after caesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average. Early identification and appropriate management of mothers at risk of peripartum haemorrhage might improve maternal and neonatal outcomes in Africa. FUNDING: Medical Research Council of South Africa.Medical Research Council of South Africa