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Critical swimming speed (Ucrit) predicts the maximum sustained swimming velocity that various fish species are able to sustain for prolonged periods. The objective of this study was to determine the Ucrit of Afrotropic ecozone fish, determine oxygen consumption at Ucrit and relate the resulting optimum flow requirements to effective movement through fishways under South African flow conditions. The selected fish species were Coptodon rendalli, Tilapia sparrmanii, Pseudocrenilabrus philander, Oreochromis mossambicus and Enteromius trimaculatus. Ucrit and oxygen consumption (MO2) were measured in a swim respirometer at 5-min intervals, at increasing velocity increments of 0.5 cm·s-1 until volitional exhaustion. No significant differences were seen in the Ucrit values between C. rendalli, T. sparrmanii and P. philander, but all species significantly differed from O. mossambicus and E. trimaculatus, which had the highest Ucrit (17.6 ± 1.5 bl·s-1 and 18.2 ± 2.8 bl·s-1). Size plays an important role in the swimming performance of fish, with larger fish able to sustain a greater velocity, which was specifically true for O. mossambicus in this study. Additionally, smaller fish consumed more oxygen during swimming and therefore used more energy, experiencing relative physiological strain. Based on these data, flow respirometry was shown to be a useful tool to determining prolonged swimming abilities of South African fish species, and can help inform the structure and flow rates of culverts and fishways. [ABSTRACT FROM AUTHOR]

The Global Forum on Maintenance and Asset Management (GFMAM) was formed in 2011 to bring together various experts, practitioners, academics, and other professionals who are active in the field of asset and maintenance management. The primary mission of GFMAM is to develop and promote knowledge, standards, and education for the maintenance and asset management professions. To fulfil this mission, GFMAM developed an 'Asset Management Landscape' document, which defines 39 subjects on asset management, grouped into six main subject areas. This paper reports on two surveys that were conducted to determine the importance of the 39 asset management subjects. Respondents were requested to rate the importance of each of the 39 subjects on a five-point scale. Results from the survey indicated that the five most important subjects are 'asset management strategy and objectives', 'asset management policy', 'strategic planning', 'asset management planning', and 'asset management leadership'. [ABSTRACT FROM AUTHOR]

Testicular histology and sperm motility were studied as possible reproductive indicators of the reproductive potential for the wild, indigenous fish species ( Clarias gariepinus) from an eutrophic impoundment, the Hartbeespoort Dam ( HD) in South Africa. Parameters used as indicators include: GSI, testes histology and staging of the testes. Computer assisted sperm analysis ( CASA), was used to assess sperm motility parameters including percent motile sperm (% MOT), velocity curvilinear ( VCL μm s−1) and progression ( PROG). These parameters were compared to C. gariepinus sampled at a reference site, the Marico Bosveld dam ( MD). Water samples from both dams were analysed for metals and selected endocrine disrupting chemicals ( EDCs). The water samples in the HD had notable high levels of selenium as well as nonylphenol and Di-n- Butyl phthalate. Macroscopic differences in the testes were found comparing the HD and MD. Fish from HD testes showed abnormalities regarding the interstitial tissue possibly due to proliferation of connective tissue. The CASA results showed no significant (P ≥ 0.05) differences for the% MOT of fish spermatozoa between HD and MD. The VCL and PROG of sperm had significant (P < 0.05) differences in fish between HD- LF, HD- HF and MD. It here fore seems that the increased environmental pollutants in the HD had an effect on reproductive status and sperm motility parameters of C. gariepinus when compared to the reference site MD. [ABSTRACT FROM AUTHOR]

Hepatic arteriovenous malformation (AVM) is a rare developmental vascular disorder characterized by direct arterial connection to a fistulous venous drainage system within the liver. The condition results in a high-flow, low-resistance shunt that can cause high-output cardiac failure and hydrops. Prenatal diagnosis is possible when sonography detects multiple engorged vascular channels in the fetal liver. Current treatment options include postnatal obliteration of the arterial feeder vessels by surgical ligation or percutaneous transcatheter embolization with detachable coils. The authors present a case of a prenatally diagnosed hepatic AVM complicated by fetal distress, high-output cardiac failure, and consumptive coagulopathy that had recanalization of feeder vessels noted two weeks after initial successful coil placement. [ABSTRACT FROM AUTHOR]

The continued high number of fatalities associated with Trackless Mobile Machines (TMMs) in South Africa have led to the introduction of Collision Avoidance System (CAS) regulations in the Mine Health and Safety Act in 2015. This has lead to the profusion of technologically-immature CASs from third-party vendors, all of which are centered on automatic stopping and braking systems. These braking systems often result in trivial or ineffective solutions, proving costly to mining operations. The combination of braking and steering control in CASs may substantially increase the solution space and provide far safer and more efficient manoeuvres. A recursive non-linear collision prediction estimator and optimal trajectory generation model was developed to evaluate the potential contribution of the addition of steering to CASs. Three independent optimal trajectory generation models are proposed to compete against one another in an attempt to synthesize the safest, most predictable, and efficient trajectory. A deep reinforcement learning, lattice optimization and Monte Carlo hyper sampling path planning model’s trajectories are evlauated using the Earth Moving Equipment Safety Round Table (EMESRT) interaction scenarios. Initial results indicate increased CAS solution spaces in collision-avoiding scenarios, providing safer and more effective solutions in high velocity vehicle interactions.

Advancements have been made in the field of vehicle dynamics, improving the handling and safety of the vehicle through control systems such as the Antilock Braking System (ABS). An ABS enhances the braking performance and steerability of a vehicle under severe braking conditions by preventing wheel lockup. However, its performance degrades on rough terrain resulting in an increased wheel lockup and stopping distance compared to without. This is largely as a result of noisy measurements, and un-modelled dynamics that occur as a result of the vertical and torsional excitation experienced over rough terrain. Therefore, it is proposed that a model-free intelligent technique, which may adapt to these dynamics, be used to overcome this problem. The Double Deep Q-learning (DDQN) technique in conjunction with a Temporal Convolutional Network (TCN) is proposed as the intelligent control algorithm, and straight line braking simulations are performed using a single tyre model, with tyre characteristics approximated by the LuGre tyre model. The rough terrain is modelled after the measured Belgian paving with the normal forces at the tyre contact patch approximated using FTire in ADAMS. Comparisons are drawn against the Bosch algorithm, and results show that the intelligent control approach achieves lateral stability by preventing wheel lockup whilst braking over rough terrain, without deteriorating the stopping distance.

The possibility of accurately inferring the external forces applied to a vehicle can directly contribute to better safety systems and thus lowers the chance of injury or loss of life. These external forces are applied to a vehicle through the tyres and are challenging to measure directly. Still, it is possible to measure acceleration, deformation, or strain on the inner surface of a tyre. These measurements are theorized to be strongly linked to the forces produced by the tyre. However, it is still unknown whether or not one can always identify external forces from internal measurements in this way. Research has mainly focused on obtaining estimates of tyre forces rather than establishing to what extent these tyre forces are identifiable. This paper investigates this by conducting a virtual experiment that simulates known external forces applied to the tyre and computes the strains and displacements inside the tyre. A virtual inverse simulation then recovers the external forces from either the deformation or strain computed on the inside of the tyre. The identifiability of the forces recovered by the virtual inverse simulation is investigated by adding artificial measurement noise and initial guess perturbations to quantify the variance in the identified forces.

A qualitative and quantitative histological assessment was done on the liver, gills and gonads. Focus was placed on reproductive health aspects by staging the gonads according to their reproductive development and assessing the motility of activated sperm using Computer Assisted Sperm Analysis. [ABSTRACT FROM AUTHOR]

Introduction: To study the feasibility and assess the correlation of qualitative and quantitative methods for an image quality (IQ) audit of a Cervical spine CT., Methods: Five radiologists retrospectively performed a blinded visual grading analysis (VGA) on 20 studies (10 from Protocol 1 and 10 from Protocol 2), using the RANZCR CT IQ Self-Audit worksheet. A Visual Grading Analysis Score (VGAS) and Area under the curve using Visual Grading Characteristics (AUC VGC ) were the figures of merit. Quantitative metrics for noise and contrast were correlated to the qualitative assessment., Results: No statistically significant difference was observed in the IQ, VGAS Protocol 1  = 0.65, 95% CI [0.54, 0.75] and VGAS Protocol 2  = 0.73, 95% CI [0.67, 0.79] and AUC VGC  = 0.548, 95% CI [0.40, 0.69]. Protocol 2 indicated a statistically significant average dose reduction of 35% in CTDI vol (P = 0.020) and a higher noise; however, the difference was statistically insignificant. There was a moderate correlation between the manual noise measurements in soft tissue and air (P = 0.035) and a strong correlation between the manual and automated noise measurements (P < 0.001). The contrast resolution-based quantitative parameter, EdgeGradientSoft, correlated to the qualitative scores (P = 0.031)., Conclusion: Validated VGA tools can be used for IQ audits; however, tailoring the image criteria and rating scale to the clinical practice is suggested. The use of contrast-based IQ metrics showed encouraging results, and further larger-scale studies are needed to explore their potential use in quality management., (© 2024 Royal Australian and New Zealand College of Radiologists.)

Post-natal growth influences short- and long-term preterm infant outcomes. Different growth charts, such as the Fenton Growth Chart (FGC) and INTERGROWTH-21st Preterm Post-natal Growth Standards (IG-PPGS), describe different growth curves and targets. This study compares FGC- and IG-PPGS-derived weight-for-postmenstrual age z-score (WZ) up to 50 weeks postmenstrual age (PMA50) for predicting 1-year anthropometry in 321 South African preterm infants. The change in WZ from birth to PMA50 (ΔWZ, calculated using FGC and IG-PPGS) was correlated to age-corrected 1-year anthropometric z-scores for weight-for-age (WAZ), length-for-age (LAZ), weight-for-length (WLZ) and BMI-for-age (BMIZ), and categorically compared with rates of underweight (WAZ < -2), stunting (LAZ < -2), wasting (WLZ < -2) and overweight (BMIZ > + 2). Multivariable analyses explored the effects of other early-life exposures on malnutrition risk. At PMA50, mean WZ was significantly higher on IG-PPGS (-0.56 ± 1.52) than FGC (-0.90 ± 1.52; p < 0.001), but ΔWZ was similar (IG-PPGS -0.26 ± 1.23, FGC -0.11 ± 1.14; p = 0.153). Statistically significant ΔWZ differences emerged among small-for-gestational age infants (FGC -0.38 ± 1.22 vs. IG-PPGS -0.01 ± 1.30; p < 0.001) and appropriate-for-gestational age infants (FGC + 0.02 ± 1.08, IG-PPGS -0.39 ± 1.18; p < 0.001). Correlation coefficients of ΔWZ with WAZ, LAZ, WLZ and BMIZ were low (r < 0.45), though higher for FGC than IG-PPGS. Compared with IG-PPGS, ΔWZ < -1 on FGC predicted larger percentages of underweight (42% vs. 36%) and wasting (43% vs. 39%) and equal percentages of stunting (33%), while ΔWZ > + 1 predicted larger percentages overweight (57% vs. 38%). Both charts performed similarly in multivariable analysis. Differences between FGC and IG-PPGS are less apparent when considering ΔWZ, highlighting the importance of assessing growth as change over time, irrespective of growth chart., (© 2024 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd.)

Background: Concussions are an ever present risk for many sports. Underlying emotional disturbances and drowsiness are associated with worse post-concussion symptom scores. Yet, not study has examined associations of both emotional disturbances and drowsiness on concussion severity and symptomology., Objectives: Examine the associations between baseline sleepiness, emotional complaints, and concussion risk and symptom severity in adolescent athletes., Methods: A cohort of 626 adolescent athletes underwent baseline/pre-season concussion screening. Those who experienced a physician diagnosed concussion underwent follow up concussion symptomology assessment. Over 90% of players were seen within two weeks of the concussion incident. Linear regression examined for associations between concussion symptom scores and baseline drowsiness and baseline emotional symptoms. Logistic regression examined for association between each symptom and baseline drowsiness and baseline emotional symptoms., Results: Of the 626 athletes that underwent baseline testing, 292 experienced a concussion. Of those 292 athletes, 174 (59.6%) reported baseline drowsiness and 183 (62.7%) baseline emotional symptoms. Baseline drowsiness and emotional complaints were associated with a 2.6 (95% confidence interval = 1.9 to 3.6) and 2.8 (95% confidence interval = 2.0 to 3.9) times greater odds of sustaining a concussion respectively. Increased symptomology after concussion was associated with both baseline drowsiness (unstandardised b = 4.6, p < 0.01) and baseline emotional complaints (unstandardised b = 6.0, p < 0.01)., Conclusion: Preseason drowsiness and emotional complaints in adolescent athletes are associated with higher risk of adverse clinical outcomes following concussion. Therefore, clinicians and coaches should be aware, and properly screen, for sleep and emotional problems as part of pre-season/baseline health screening., Competing Interests: Conflict of interest and source of funding: The authors declare no source of funding. DS receives salary from NeuroFlex Inc, Canada, however, this manuscript is independent of his work there. DS and LH report grants (Flinders Foundation) regarding concussion which is independent to this manuscript. GV, HR, PDJ, and LH are sports physicians, who treat concussion as part of their employment. RG and TB report no competing interests.