Developing an outcomes-based charter to direct teaching and assessment of medical professionalism

Background. Components of professionalism in undergraduate medical studies at the University of  Pretoria (UP) were previously defined as nine ‘Golden Threads’. Although specific outcomes were  formulated for the threads, the need for more explicit professional standards became increasingly evident. The restructuring of the health system in South Africa contributed to the need for more explicit standards. The Charter for Medical Professionalism was developed during 2006 - 2008 as a reference document within the local context to serve as a standard for professionalism in the medical curriculum. Another aim was to guide academics in medical studies to act as good role models of professional behaviour.Objective. To document the development of the Charter for Medical Professionalism and to evaluate  lecturer and student perceptions on the formulation of the Charter to make appropriate changes and increase acceptance.Methods. The project took the form of action research, and a working group comprising academics from UP’s Faculty of Health Sciences developed the Charter from relevant source documents, employing thematic and content analysis and recursive abstraction. An online survey was conducted to assess lecturer and student acceptance of the Charter.Results. The outcomes-based approach was perceived as acceptable and appears to broaden the scope of assessment of professionalism.Conclusion. Inclusion of outcomes proposed by other work groups relating to research, practice   management, teaching, mentoring and leadership roles of the medical doctor may be considered in future

Ondersoek na seleksiemaatstawwe by Afrinoskape. Genetiese parameters van groei- en woleienskappe

Investigation of selection criteria for Afrino sheep. Genetic parameters of growth and wool traits. The data used in this study were obtained from the Carnarvon Afrino stud. The genetic and phenotypic parameters for the various growth and wool traits were estimated by means of Henderson's Method III. The following traits were considered as possible selection criteria for ram selection: weaning weight (h2 = 0,21 ± O,07), yearling weight (h2 = 0,22 ± 0,07), ADG: weaning-year-old (h2 = 0,22 ± 0,07), Kleiber: weaning-year-old (h = 0,23 ± 0,07), and eighteen-month mass (h2 = 0,28 ± 0,08). However, the traits yearling weight, ADG: weaning-year-old and eighteen month mass cannot be considered as possible selection criteria because of their undesirable genetic correlations with birth mass and eighteen-month mass. Kleiber: weaning-year-old had a non-significant negative genetic correlation of -0,12 ± 0,22 with birth mass, a medium positive correlation with yearling weight (0,35 ± 0,21) and it is almost unrelated to eighteen-month mass (rg = 0,10 ± 0,22). At 12 months of age, rams can be selected on the basis of the following selection index: I=3 X weaning mass -- 1 X Kleiber: weaning-year-old- 18 X fibre diameter.Ondersoek is ingestel na geskikte seleksiemaatstawwe vir Afrino-skape. Data vanaf die Camarvonse Afrinokudde is vir hierdie ondersoek gebruik. Genetiese en fenotipiese parameters van die onderskeie groei- en woleienskappe is met behulp van Henderson se Metode III beraam. Die volgende eienskappe is as moontlike seleksiemaatstawwe vir ramseleksie oorweeg: speenmassa (h2 = 0,21 ± 0,07), jaarmassa (h2 = 0,22 ± 0,07), GDT: speen-jaar (h2 = 0,22 ± 0,07), Kleiber: speen-jaar (h2 = 0,23 ± 0,07), en agtienmaandemassa (h2 = 0,28 ± 0,08). Jaarmassa, GDT: speenjaar en agtienmaandemassa is as gevolg van hul ongunstige genetiese korrelasies met geboortemassa en agtienmaandemassa as seleksiemaatstawwe geelimineer. Kleiber: speen-jaar het 'n nie-betekenisvolle negatiewe korrelasie van -0,12 ± 0,22 met geboortemassa, 'n matig-positiewe korrelasie van 0,35 ± 0,21 met jaarmassa en is feitlik onafhanklik van agtienmaandemassa (rg = 0,10 ± 0,22). Ramme kan op 12-maande-ouderdom op grond van die volgende seleksie-indeks geselekteer word: I = 3 X speenmassa + 1 X Kleiber: speen-jaar - 18 X veseldikte.Keywords: Afrino, genetic parameters, growth traits, Kleiber ratio

Optimization of heliostat pod structure for wind loads

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.There is a great need to design cost-effective heliostat arrangements for use in solar power plants. Ideal optimization of the design would be to minimize material and to allow for simple field assembly. The purpose of this study is to develop a parametric finite element model that allows for optimization of a modular heliostat structure, the HelioPod. Static wind profiles are generated using aerodynamic coefficients and steady-state ANSYS® Fluent computational fluid dynamics analyses. The heliostat base structure is built using ANSYS® finite element analysis software utilizing beam elements. These elements decrease run time and are simple enough that the geometry of the section can be easily changed. The existing frame is analyzed as base design, and 5 candidate optimum designs are determine using response surface optimization from 95 design points. In this initial study, the pylon diameter and wall thickness are shown to be the most sensitive parameters in reducing the mass and total deformation of the structure.cf201

Impact of Mesoporous Silicon Template Pore Dimension and Surface Chemistry on Methylammonium Lead Trihalide Perovskite Photophysics

© 2020 Wiley-VCH GmbH In influencing fundamental properties—and ultimately device performance—of lead halide perovskites, interfacial interactions play a major role, notably with regard to carrier diffusion and recombination. Here anodized porous Si (pSi) as well as porous silica particles are employed as templates for formation of methylammonium lead trihalide nanostructures. This allows synthesis of relatively small perovskite domains and comparison of associated interfacial chemistry between as-prepared hydrophobic hydrideterminated functionalities and hydrophilic oxide-terminated surfaces. While physical confinement of MAPbBr3 has a uniform effect on carrier lifetime, pore size (7–18 nm) of the silicon-containing template has a sensitive influence on perovskite photoluminescence (PL) wavelength maximum. Furthermore, identity of the surface functionality of the template significantly alters the PL quantum efficiency, with lowest PL intensity associated with the H-terminated pSi and the most intense PL affiliated with the oxideterminated pSi surface. These effects are explored for green-emitting MAPbBr3 as well as infrared-emitting MAPbI3. In addition, the role of silicon surface chemistry on the time-dependent stability of these perovskites packaged within a given mesoporous template is also evaluated, specifically, a lack of miscibility between MAPbI3 and the H-terminated pSi template results in a diffusion of this specific perovskite composition eluting from this porous matrix over time

Congenital anomalies in black South African liveborn neonates at an urban academic hospital

Study objective. The aim was to study the spectrum of clinical problems and outcomes in infants born at an urban academic hospital. In consequence, as part of the overall study, the incidence of congenital anomalies and the outcomes of affected infants were recorded.Design. This was a prospective, hospital-based study, undertaken on liveborn infants born over a 3-year period, 1 May 1986 to 30 April 1989.Setting. Kalafong Hospital, Pretoria.Main results. A total of 17 351 liveborn infants was examined and the total congenital anomalies incidence was 11 ,87 per 1 000 Iivebirths. The central nervous system was the system most frequently involved (2,30 per 1 000 livebirths), followed by the musculoskeletal system (2,13 per 1 000 livebirths). The commonest individual congenital anomaly was Down syndrome (1,33 per 1 000 Iivebirths), followed by neural tube defects (0,99 per 1 000 livebirths) and ventricular septal defects (0,69 per 1 000 livebirths). In 11 % (2,25 per 1 000 livebirths) of neonatal deaths, infant loss was attributable to congenital anomalies.Conclusions. The incidence of congenital anomalies in black South African neonates, born in an urban setting, is as high as in other First- and Third-World countries, and the incidence of some individual congenital anomalies is higher. This study indicates the need for further research and the establishment of prenatal, genetics and paediatric facilities to manage these problems

Giardia duodenalis and Cryptosporidium occurrence in Australian sea lions (Neophoca cinerea) exposed to varied levels of human interaction

AbstractGiardia and Cryptosporidium are amongst the most common protozoan parasites identified as causing enteric disease in pinnipeds. A number of Giardia assemblages and Cryptosporidium species and genotypes are common in humans and terrestrial mammals and have also been identified in marine mammals. To investigate the occurrence of these parasites in an endangered marine mammal, the Australian sea lion (Neophoca cinerea), genomic DNA was extracted from faecal samples collected from wild populations (n = 271) in Southern and Western Australia and three Australian captive populations (n = 19). These were screened using PCR targeting the 18S rRNA of Giardia and Cryptosporidium. Giardia duodenalis was detected in 28 wild sea lions and in seven captive individuals. Successful sequencing of the 18S rRNA gene assigned 27 Giardia isolates to assemblage B and one to assemblage A, both assemblages commonly found in humans. Subsequent screening at the gdh and β-giardin loci resulted in amplification of only one of the 35 18S rRNA positive samples at the β-giardin locus. Sequencing at the β-giardin locus assigned the assemblage B 18S rRNA confirmed isolate to assemblage AI. The geographic distribution of sea lion populations sampled in relation to human settlements indicated that Giardia presence in sea lions was highest in populations less than 25 km from humans. Cryptosporidium was not detected by PCR screening in either wild colonies or captive sea lion populations. These data suggest that the presence of G. duodenalis in the endangered Australian sea lion is likely the result of dispersal from human sources. Multilocus molecular analyses are essential for the determination of G. duodenalis assemblages and subsequent inferences on transmission routes to endangered marine mammal populations

Fluid management in diabetic-acidosis — Ringer’s lactate versus normal saline : a randomized controlled trial

OBJECTIVE: To determine if Ringer’s lactate is superior to 0.9% sodium chloride solution for resolution of acidosis in the management of diabetic ketoacidosis (DKA). DESIGN: Parallel double blind randomized controlled trial. METHODS: Patients presenting with DKA at Kalafong and Steve Biko Academic hospitals were recruited for inclusion in this study if they were >18 years of age, had a venous pH >6.9 and 47.2, a blood glucose of >13 mmol/l and had urine ketones of 52+. All patients had to be alert enough to give informed consent and should have received <1 l of resuscitation fluid prior to enrolment. RESULTS: Fifty-seven patients were randomly allocated, 29 were allocated to receive 0.9% sodium chloride solution and 28 to receive Ringer’s lactate (of which 27 were included in the analysis in each group). An adjusted Cox proportional hazards analysis was done to compare the time to normalization of pH between the 0.9% sodium chloride solution and Ringer’s lactate groups. The hazard ratio (Ringer’s compared with 0.9% sodium chloride solution) for time to venous pH normalization (pH = 7.32) was 1.863 (95% CI 0.937–3.705, P = 0.076). The median time to reach a pH of 7.32 for the 0.9% sodium chloride solution group was 683 min (95% CI 378–988) (IQR: 435–1095 min) and for Ringer’s lactate solution 540 min (95% CI 184–896, P = 0.251). The unadjusted time to lower blood glucose to 14 mmol/l was significantly longer in the Ringer’s lactate solution group (410 min, IQR: 240–540) than the 0.9% sodium chloride solution group (300 min, IQR: 235–420, P = 0.044). No difference could be demonstrated between the Ringer’s lactate and 0.9% sodium chloride solution groups in the time to resolution of DKA (based on the ADA criteria) (unadjusted: P = 0.934, adjusted: P = 0.758) CONCLUSION: This study failed to indicate benefit from using Ringer’s lactate solution compared to 0.9% sodium chloride solution regarding time to normalization of pH in patients with DKA. The time to reach a blood glucose level of 14 mmol/l took significantly longer with the Ringer’s lactate solution.University of Pretoria, Research Development Programmehttp://qjmed.oxfordjournals.org

Correcting the Bias of Empirical Frequency Parameter Estimators in Codon Models

Markov models of codon substitution are powerful inferential tools for studying biological processes such as natural selection and preferences in amino acid substitution. The equilibrium character distributions of these models are almost always estimated using nucleotide frequencies observed in a sequence alignment, primarily as a matter of historical convention. In this note, we demonstrate that a popular class of such estimators are biased, and that this bias has an adverse effect on goodness of fit and estimates of substitution rates. We propose a “corrected” empirical estimator that begins with observed nucleotide counts, but accounts for the nucleotide composition of stop codons. We show via simulation that the corrected estimates outperform the de facto standard estimates not just by providing better estimates of the frequencies themselves, but also by leading to improved estimation of other parameters in the evolutionary models. On a curated collection of sequence alignments, our estimators show a significant improvement in goodness of fit compared to the approach. Maximum likelihood estimation of the frequency parameters appears to be warranted in many cases, albeit at a greater computational cost. Our results demonstrate that there is little justification, either statistical or computational, for continued use of the -style estimators

Selective Constraints on Amino Acids Estimated by a Mechanistic Codon Substitution Model with Multiple Nucleotide Changes

Empirical substitution matrices represent the average tendencies of substitutions over various protein families by sacrificing gene-level resolution. We develop a codon-based model, in which mutational tendencies of codon, a genetic code, and the strength of selective constraints against amino acid replacements can be tailored to a given gene. First, selective constraints averaged over proteins are estimated by maximizing the likelihood of each 1-PAM matrix of empirical amino acid (JTT, WAG, and LG) and codon (KHG) substitution matrices. Then, selective constraints specific to given proteins are approximated as a linear function of those estimated from the empirical substitution matrices. Akaike information criterion (AIC) values indicate that a model allowing multiple nucleotide changes fits the empirical substitution matrices significantly better. Also, the ML estimates of transition-transversion bias obtained from these empirical matrices are not so large as previously estimated. The selective constraints are characteristic of proteins rather than species. However, their relative strengths among amino acid pairs can be approximated not to depend very much on protein families but amino acid pairs, because the present model, in which selective constraints are approximated to be a linear function of those estimated from the JTT/WAG/LG/KHG matrices, can provide a good fit to other empirical substitution matrices including cpREV for chloroplast proteins and mtREV for vertebrate mitochondrial proteins. The present codon-based model with the ML estimates of selective constraints and with adjustable mutation rates of nucleotide would be useful as a simple substitution model in ML and Bayesian inferences of molecular phylogenetic trees, and enables us to obtain biologically meaningful information at both nucleotide and amino acid levels from codon and protein sequences.Comment: Table 9 in this article includes corrections for errata in the Table 9 published in 10.1371/journal.pone.0017244. Supporting information is attached at the end of the article, and a computer-readable dataset of the ML estimates of selective constraints is available from 10.1371/journal.pone.001724

Phototherapy and exchange transfusion for neonatal hyperbilirubinaemia

The purpose of this document is to address the current lack of consensus  regarding the management of hyperbilirubinaemia in neonates in South Africa. If left untreated, severe neonatal hyperbilirubinaemia may cause kernicterus and ultimately death and the severity of neonatal jaundice is often underestimated clinically. However, if phototherapy is instituted  timeously and at the correct intensity an exchange transfusion can usually be avoided. The literature describing intervention thresholds for  phototherapy and exchange transfusion in both term and preterm infants is therefore reviewed and specific intervention thresholds that can be used throughout South Africa are proposed and presented graphically. A simplified version for use in a primary care setting is also presented. All academic heads of neonatology departments throughout South Africa were consulted in the process of drawing up this document and consensus was achieved