The kaolinitic clay deposits on Beaconsfield, north of Grahamstown

The Grahamstown clay deposits occur below the Grahamstown Formation silcrete, which forms a remnant of an extensive peneplain that developed on the African erosion surface during the Cretaceous–Tertiary period. This paper provides new data on the distribution of the kaolinitic clay deposits in the Beaconsfield area north of Grahamstown. These data include 23 borehole profiles through the deposits, and the chemistry and mineralogy of the clays. Relatively little information is available on this part of the peneplain. It was found that the thickness of the kaolin horizon varies considerably, but reaches 35m in places. It generally occurs under a silcrete cover, which attains a thickness of 8 m in places. Lithological logs enable direct comparison across the Beaconsfield area. The clays are developed in both the Witteberg Group shale and Dwyka Group tillite. The contact between the clay and underlying bedrock is gradational and relatively uneven. Major-element X-ray fluorescence analyses revealed that there is chemical variation, both vertically and laterally. Al2O3 content is generally near 20%, but may reach 29%. SiO2 content varies between 55 and 70+%. SiO2 contents are highest in the silcretes occurring just below soil level. Fe2O3 is high locally in the top part of the profile. K2O and Na2O are generally low, but increase towards the unweathered bedrock as the primary feldspar content increases. These compositional variations are compatible with residual concentrations of kaolinitic clays through deep weathering below the former African erosion surface

Supplying lava eruptions in the Karoo Province, South Africa: a geochemical comparison of the volcanic sequence with intrusions in the main Karoo basin

Magma supply for lava eruptions remains a poorly understood facet of continental flood volcanism. In the Karoo Province a vast complex of dolerite sheets and dykes is exposed in the main Karoo sedimentary basin underlying the flood basalt remnant of Lesotho (Drakensberg Group) suggesting that lavas were erupted locally from a widely distributed network of fissures

Two cultures, one identity: formulations of Australian Isma'ili Muslim identity

The Shi'a Imami Nizari Isma'ili Muslims have often been considered the "poster child" for pluralistic integration (Cayo 2008). This ethos has been inculcated within members of the community, with its adherents seeing themselves as a diverse and multi-ethnic collective. Nevertheless, despite this purported pluralism, social research on the Isma'ilis has primarily focused on the diasporic and post-diasporic migrant communities of South Asian descent, the 'first and second-generation immigrants,' in the Euro-American context (Mukadam and Mawani 2006, 2009; Nanji 1983, 1986). The experiences of co-religionists in other contexts have often been neglected. This study examines how members of the self-described geographically and socially isolated Isma'ili community in Australia construct their identity vis-à-vis the larger, global, Isma'ili community, and how they have responded to the potential of identity threat given the arrival of another group of Isma’ilis with a differing migratory history integrating into the extant community. Using the approach of identity process theory, this study examines how salient features of identity are constructed amongst the Australian Isma'ilis, how religion and identity take on multiple meanings within the Australian Isma'ili context, and, finally, sheds light on the self-sufficiency of this community despite geographic and social isolation

Extended Thromboprophylaxis with Betrixaban in Acutely Ill Medical Patients

Background Patients with acute medical illnesses are at prolonged risk for venous thrombosis. However, the appropriate duration of thromboprophylaxis remains unknown. Methods Patients who were hospitalized for acute medical illnesses were randomly assigned to receive subcutaneous enoxaparin (at a dose of 40 mg once daily) for 10±4 days plus oral betrixaban placebo for 35 to 42 days or subcutaneous enoxaparin placebo for 10±4 days plus oral betrixaban (at a dose of 80 mg once daily) for 35 to 42 days. We performed sequential analyses in three prespecified, progressively inclusive cohorts: patients with an elevated d-dimer level (cohort 1), patients with an elevated d-dimer level or an age of at least 75 years (cohort 2), and all the enrolled patients (overall population cohort). The statistical analysis plan specified that if the between-group difference in any analysis in this sequence was not significant, the other analyses would be considered exploratory. The primary efficacy outcome was a composite of asymptomatic proximal deep-vein thrombosis and symptomatic venous thromboembolism. The principal safety outcome was major bleeding. Results A total of 7513 patients underwent randomization. In cohort 1, the primary efficacy outcome occurred in 6.9% of patients receiving betrixaban and 8.5% receiving enoxaparin (relative risk in the betrixaban group, 0.81; 95% confidence interval [CI], 0.65 to 1.00; P=0.054). The rates were 5.6% and 7.1%, respectively (relative risk, 0.80; 95% CI, 0.66 to 0.98; P=0.03) in cohort 2 and 5.3% and 7.0% (relative risk, 0.76; 95% CI, 0.63 to 0.92; P=0.006) in the overall population. (The last two analyses were considered to be exploratory owing to the result in cohort 1.) In the overall population, major bleeding occurred in 0.7% of the betrixaban group and 0.6% of the enoxaparin group (relative risk, 1.19; 95% CI, 0.67 to 2.12; P=0.55). Conclusions Among acutely ill medical patients with an elevated d-dimer level, there was no significant difference between extended-duration betrixaban and a standard regimen of enoxaparin in the prespecified primary efficacy outcome. However, prespecified exploratory analyses provided evidence suggesting a benefit for betrixaban in the two larger cohorts. (Funded by Portola Pharmaceuticals; APEX ClinicalTrials.gov number, NCT01583218. opens in new tab.

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme