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The Palaeoproterozoic sandstones and quartzites of the Pretoria Group (Transvaal Supergroup) in the Transvaal Basin of South Africa are important markers for regional correlations and dating of events of global importance (e.g., the Great Oxidation Event). The succession has few independent age markers, and much of the discussion about the time of deposition and the source of material of these rocks has been based on data from detrital zircon suites. The clastic sedimentary rocks of the Pretoria Group contain detrital zircon grains ranging from the Mesoarchaean to ages that are near-contemporaneous to, and even younger than the overlying and crosscutting igneous rocks of the Bushveld Complex. We show that the U-Pb age and Lu-Hf isotope distributions of the detrital zircon population in the Pretoria Group are the result of three different types of processes, acting successively: (1) Crystallisation in the igneous or metamorphic protosource rock (i.e., the rock where the zircon originally crystallised), (2) Metamorphic and hydrothermal resetting of the U-Pb chronometer induced by emplacement and crystallisation of the 2 055 Ma Bushveld Complex, and (3) Late, low-temperature processes (e.g., weathering). Critical age markers of maximum ages of deposition obtained after excluding effects of (2) and (3) are the 2 200 Ma Magaliesberg Formation (outside of the Bushveld aureole) and the 2 080 to 2 100 Ma Lakenvalei Formation. The Leeuwpoort Formation is a worst-case example, containing both young (<2 200 Ma) unmodified detrital zircon and hydrothermally altered zircon in the same age range. The two can only be distinguished from trace element analyses. Age distributions of Archaean and early Palaeoproterozoic zircon age fractions overlap with detrital zircon age suites in lower (i.e., pre-Timeball Hill Formation) parts of the Transvaal Supergroup, suggesting recycling within the basin or from the basin margin. Overlaps in 2 200 to 2 350 Ma zircon ages with those of volcanogenic zircon in the Timeball Hill Formation again suggest recycling. The origin of 2 080 to 2 150 Ma zircon is uncertain, but neither poorly constrained sources in the Kaapvaal Craton (e.g., Okwa Basement Complex) nor recycling of volcanogenic material from post-Magaliesberg formations can be ruled out. [ABSTRACT FROM AUTHOR]

Two small exposures of quartz-porphyritic rocks occur on the farm Zoutpekel 98 in the Marydale Terrane between the Doornberg Fault and Brakbos Shear Zone, apparently overlying Kaapvaal basement granite but lacking clear field relationships due to sand and Dwyka tillite cover. They are lavas and tuffs, metamorphosed in lower amphibolite facies. They contain quartz phenocrysts with a distinctive blue colour, due to metamorphic exsolution of rutile. Microbeam U-Pb zircon dating gives a combined 207Pb/206Pb age of 2 722 ± 3 Ma (seven determinations on four samples), interpreted as the age of extrusion. Three of these samples give the same discordia upper intercept age, but one sample gives discordia intercepts of 2 688 ± 15 and 1 223 ± 120 Ma, thought to reflect metamorphic lead loss related to the ~1 210 Ma Namaqua terrane assembly collisions. The Zoutpekel exposures are coeval with the 2 720 ± 2 Ma Makwassie Formation of the Platberg Group, Ventersdorp Supergroup. They also correspond geochemically to the Makwassie Formation and no other unit of the supergroup. A sample from the T'kuip Formation of the nearest Ventersdorp Supergroup inlier on the Kaapvaal Craton (east of the Doornberg Fault), gives an age of 2 716 ± 8 Ma, also confirming its lithostratigraphic and geochemical correlation with the Makwassie Formation. The Zoutpekel exposures show that not only the Kaapvaal basement granites, but also the supracrustal cover rocks of the Ventersdorp Supergroup, extend southwards across the Doornberg Fault, The Marydale Terrane is thus not an exotic terrane, but probably represents a passive continental margin developed at the beginning of the 1 300 to 1 000 Ma Namaqua-Natal Wilson cycle. The age range of the Ventersdorp Supergroup and the age and stratigraphic correlation of the Marydale Group thrust complex, which straddles the Zoutpekel exposures, will be investigated in two companion papers. [ABSTRACT FROM AUTHOR]

Summary: Computed tomography (CT) with CT myelography is a novel imaging modality for detailed anatomical imaging and precise diagnosis of equine cervical spine pathology. Computed tomography of the complete cervical vertebral column in live horses has not been reported previously. The objectives of this study were to describe the diagnostic utility of CT and CT myelography in horses, the technique, the type and distribution of lesions and procedure‐related complications. Medical records of horses subjected to cervical CT and CT myelography between 2013 and 2018 were reviewed for this retrospective descriptive study. The examinations were performed with horses in lateral recumbency using a large‐bore CT scanner. In total, 180 horses were included. The study population consisted of 79.4% Warmblood breed horses, 68.3% were male, the mean age was 7.1 years (range 21 days–21 years), and the bodyweight ranged from 61 to 717 kg (mean 530 kg). Pathology of the cervical vertebral column was identified in 176/180 horses (97.8%) and included osteoarthritis of the articular process joints in 83%. Impingement and compression of the spinal cord were detected using CT myelography in 125/147 horses (85%). Pathology was localised caudal to C5 in 90%. The mean ± s.d. anaesthesia time was 34 ± 19 min and 52 ± 13 min for CT examinations, excluding and including myelography, respectively. Adverse events occurred in 7.2% of the examined horses. The caudal location of the majority of lesions emphasises the importance of good‐quality imaging of the most caudal cervical vertebrae in horses with suspected cervical spinal pathology and/or spinal cord compression. Computed tomography imaging enables identification of bony and soft tissue lesions of the entire cervical vertebral column in live, large‐breed adult horses. [ABSTRACT FROM AUTHOR]

Synovial sepsis represents a major cause of morbidity and mortality in foals; however, there are no studies focusing on foals particularly at risk during the first 2 months of life. Our objective was to analyse outcome in foals aged <2 months with haematogenous septic arthritis and to identify prognostic factors and compare the effects of two different lavage procedures on outcome. Sixty foals with synovial sepsis were used for our retrospective study in which medical records, online data and telephone interviews were utilised to analyse prognostic factors, and determine short- and long-term survival and athletic performance of foals treated at Evidensia Equine Specialist Hospital, Helsingborg, between 2008 and 2014. Overall survival to discharge was 80% (48/60). Time to long-term follow-up ranged from 6 months to 6.5 years. Forty/60 (67%) horses survived long-term. Four/8 (50%) of the nonsurvivors at long-term follow-up had been subjected to euthanasia due to sequelae of joint sepsis. Of the long-term survivors, 37/40 (92.5%) achieved athletic soundness. Overall long-term outcome for athletic soundness was 37/60 (62%). Prognostic factors based on historical, clinical or laboratory data, or the use of through-and-through needle lavage compared to endoscopic lavage as the first procedure, could not be identified. The present study demonstrates a more favourable prognosis than previously reported, with 80% of foals with synovial sepsis surviving to discharge, and approximately 60% achieving athletic soundness. However, the study was limited by a small population size, which may account for the failure to verify statistically significant prognostic factors. [ABSTRACT FROM AUTHOR]

Temporomandibular joint ( TMJ) pathology is a rarely reported cause of decreased performance among equine athletes or at least seldom recognised. This case report describes the work-up of a high level dressage horse with decreased performance. Temporomandibular joint pathology was suspected based on computed tomography ( CT) and the horse responded very well to joint treatment. [ABSTRACT FROM AUTHOR]

Bioelectrical impedance analysis (BIA) is in widespread use, but there is uncertainty about its validity in patients with metal implants or after acute hip fracture and surgery. We aimed to investigate the use of single frequency tetrapolar BIA in patients with hip fracture by answering the following questions: 1) Are BIA measurements affected by recent hip fracture and surgical repair? 2) Are BIA measurements affected by the presence of metal implants used in hip fracture surgery?

The ballistic perforation resistance of 50 mm thick concrete slabs impacted by 20 mm diameter ogive-nose steel projectiles is investigated experimentally and numerically. Three commercially produced concretes with nominal unconfined compressive strengths of 35, 75 and 110 MPa were used to cast material test specimens and slabs. After curing, ballistic impact tests were carried out to determine the ballistic limit curve and velocity for each slab quality. Material tests instrumented with digital image correlation (DIC) were conducted along the ballistic impact tests. DIC measurements were used to establish engineering stress-strain curves for calibration of a modified version of the Holmquist-Johnson-Cook concrete model. Finite element simulations of the impact tests gave good conservative predictions.