1,773 research outputs found

    Heydrichia cerasina sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta) from the southernmost tip of Africa. Phycologia, 51(1): 11- 21

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    A new species of Heydrichia (Sporolithales), H. cerasina sp. nov., is described, found only on pebbles in the low intertidal zone along a 10 km stretch of the South African south coast from Cape Agulhas to Struisbaai. The species is characterized by the following suite of features that distinguish it from the other two species of Heydrichia found in South Africa: 1) unusual cherry-red colour when freshly collected; 2) uniformly warty growth from; 3) relatively thin crust (to 1400 µm thick); 4) tetra/bisporangial sori comprised of mostly single sporangial chambers; and 5) unbranched spermatangial structures distributed on the floor, walls and roof of the mature male conceptacle. The species appears to be most closely related to H. homalopasta from Australia. This study has affirmed that the distribution of spermatangial structures within male chambers is a feature that cannot be used to separate Heydrichia from Sporolithon, the only other genus in Sporolithales, although features of thallus construction and tetra/bisporangia continue to distinguish the genera. A key to the southern African species from the order Sporolithales is provided.Web of Scienc

    Atopic dermatitis: tacrolimus vs. topical corticosteroid use

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    Atopic dermatitis (AD), the dermatological manifestation of the atopic diathesis, has a variety of clinical presentations. It is a chronic and relapsing inflammatory disorder, requiring a multifaceted treatment approach. Topical corticosteroids are the backbone of therapy. However, concerns over adverse drug reactions associated with their long-term application limit their use. Tacrolimus, on the other hand, has been shown to be effective in stabilising the symptoms of AD in the long-term setting, without the side-effects that hamper the use of topical corticosteroids. Long-term safety data up to ten years are available in the literature. Despite this, the US Food and Drug Administration (FDA) black box warning of possible malignancies has resulted in much debate among experts. The main focus of this article is to compare the safety and efficacy of topical corticosteroids to calcineurin inhibitors, particularly tacrolimus. Furthermore, the aim is to evaluate the place of tacrolimus in AD therapy. A brief overview of the condition and other treatment modalities will also be discussed.Keywords: atopic dermatitis, tacroliums, topical corticosteroid us

    The genus Phymatolithon (Hapalidiaceae, Corallinales, Rhodophyta) in South Africa, including species previously ascribed to Leptophytum

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    AbstractOf the genera within the coralline algal subfamily Melobesioideae, the genera Leptophytum Adey and Phymatolithon Foslie have probably been the most contentious in recent years. In recent publications, the name Leptophytum was used in quotation marks because South African taxa ascribed to this genus had not been formally transferred to another genus or reduced to synonymy. The status and generic disposition of those species (L. acervatum, L. ferox, L. foveatum) have remained unresolved ever since Düwel and Wegeberg (1996) determined from a study of relevant types and other specimens that Leptophytum Adey was a heterotypic synonym of Phymatolithon Foslie. Based on our study of numerous recently collected specimens and of published data on the relevant types, we have concluded that each of the above species previously ascribed to Leptophytum represents a distinct species of Phymatolithon, and that four species (incl. P. repandum) of Phymatolithon are currently known to occur in South Africa.Here we present detailed illustrated accounts of each of the four species, including: new data on male and female/carposporangial conceptacles; ecological and morphological/anatomical comparisons; and a review of the information on the various features used previously to separate Leptophytum and Phymatolithon. Southern African species ascribed to the genus Phymatolithon may be separated from one another in the field by their growth forms, the substrata on which they are generally found, and the colour of living thalli. A key for identifying southern African specimens in the field is included. Our data support the conclusion that the characters upon which Leptophytum is based are unreliable for generic delimitation from Phymatolithon

    Translating metaphors into Afrikaans in a source language-oriented translation of the Hebrew Bible

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    The impact of selected stakeholders on family business continuity and family harmony

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    The growth, survival and success of a family business are often influenced by issues relating to family relationships and family harmony. Not only do the actions of family members influence the success or failure of the family business, but so does the behaviour of non-family stakeholders. The success or failure of the family business may also have important emotional and financial ramifications for the different stakeholders involved in the business, whether that involvement is physical or emotional. Yet, very little is known about the impact that the various stakeholder groups have on the success of the family business, its continuity or the family harmony that prevails. Consequently, the primary objective of this study is to evaluate the impact of selected stakeholders, namely non-family members, inactive family members, the senior generation and the incumbent generation on the success of family businesses. Success, for the purposes of this study, was measured using two variables, family harmony and perceived future continuity. Respondents were identified by means of convenience sampling,and a total of 468 usable questionnaires were returned. The data collected were subjected to various statistical analyses. The validity of the measuring instrument was assessed by means of an exploratory factor analysis and reliability by calculating Cronbach’s alpha coefficients. The relationships proposed in the hypothesised model were assessed by means of structural equation modelling (SEM).The empirical results of this study reveal that family harmony influences the perceived future continuity of family businesses. In turn, inactive family members and the incumbent generation have a significant impact on the family harmony that exists in the family business.Key words: family business, inactive stakeholders, active stakeholders, continuity, family harmon

    Spalling of concrete in fire-an overview and local relevance

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    Concrete has traditionally been considered as a material with favourable fire resistance. The development of modern concretes with low permeability has, however, resulted in the increased occurrence of spalling when exposed to fire. Recent fire damage in South Africa during the riots in July 2021 resulted in such damage. This paper presents an overview of explosive spalling of concrete in fire, recent local observations, and developments in the field. It is shown that various (often interrelated) factors influence the susceptibility of concrete to spall in fire, and that much research is still needed to fully understand the phenomenon and, specifically, how to accurately predict its occurrence. Recent observations in South Africa support conclusions in the literature that, as an accidental loading case or as life-safety performance criteria, overall structural integrity is rarely compromised. However, as the use of higher concrete grades increases, the relevance of this risk should be considered by practising engineers.http://www.journals.co.za/ej/ejour_civileng.htmlam2024Civil EngineeringSDG-09: Industry, innovation and infrastructur

    Semileptonic weak Hamiltonian to O(ααs(μLattice))\mathcal{O}(\alpha \alpha_s(\mu_{\mathrm{Lattice}})) in momentum-space subtraction schemes

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    The CKM unitarity precision test of the Standard Model requires a systematic treatment of electromagnetic and strong corrections for semi-leptonic decays. Electromagnetic corrections require the renormalization of a semileptonic four-fermion operator. In this work we calculate the O(ααs)\mathcal{O}(\alpha\alpha_s) perturbative scheme conversion between the MSˉ\bar{\rm MS} scheme and several momentum-space subtraction schemes, which can also be implemented on the lattice. We consider schemes defined by MOM and SMOM kinematics and emphasize the importance of the choice of projector for each scheme. The conventional projector, that has been used in the literature for MOM kinematics, generates QCD corrections to the conversion factor that do not vanish for α=0\alpha=0 and which generate an artificial dependence on the lattice matching scale that would only disappear after summing all orders of perturbation theory. This can be traced to the violation of a Ward identity that holds in tha α=0\alpha =0 limit. We show how to remedy this by judicious choices of projector, and prove that the Wilson coefficients in those schemes are free from pure QCD contributions. The resulting Wilson coefficients (and operator matrix elements) have greatly reduced scale dependence. Our choice of the MSˉ\bar{\rm MS} scheme over the traditional WW-mass scheme is motivated by the fact that, besides being more tractable at higher orders, unlike the latter it allows for a transparent separation of scales. We exploit this to obtain renormalization-group-improved leading-log and next-to-leading-log strong corrections to the electromagnetic contributions and study the (QED-induced) dependence on the lattice matching scale.Comment: 1+22 page

    Predicting the growth and feed intake of Boer goats in a feedlot system

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    This research sought to develop a mathematical model to predict the growth and feed intake of Boer goat kids destined for slaughter. Data were collected from castrated kids that were housed in individual pens and fed diets that varied in energy content (11.3, 12.0, and 12.7 MJ metabolizable energy (ME)/kg feed). Growth and feed intake were monitored weekly for 20 weeks, from the time that the kids weighed 22.2 ± 3.5 kg until they were slaughtered at 48.3 ± 0.8 kg. The linear equation (bodyweight = 0.202 age – 5.241 (R2 = 0.84)) was found to predict the growth of kids between 126 and 266 days old. Correlations between expressions of intake and bodyweight were evaluated, cumulative feed intake and bodyweight being most highly correlated (r = 0.93). Linear models were developed to predict cumulative feed intake from bodyweight for goats fed each diet. Regression coefficients were compared between diets, with the slope of the equation for goats on the low energy diet (6.74 ± 0.25) being greater than that of the medium (5.80 ± 0.23) and high energy diets (5.82 ± 0.23). This indicates that goats on the medium and high energy diets gained weight more efficiently than those on the low energy diet. The results from this study can be used by goat producers to predict the growth and intake of goats and determine the ideal feedlot finishing period for optimal productivity.______________________________________________________________________________________Keywords: cumulative intake, dietary energy, modellin

    Percutaneous endoscopic gastrostomy in children a 5-year experience

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    Introduction. Percutaneous endoscopic gastrostomy (PEG) has been performed on children since 1979. The indications for a PEG are wide ranging and while there are well-established benefits, it remains a procedure with recognised complications.Goals and objectives. The goal of this study was to review our experience with this procedure at a South African paediatric tertiary referral hospital over a 5-year period. The objectives were to review PEGs with regard to patient characteristics, indications, anaesthesia time required and complications.Methods. The study was a retrospective case record review.Results. A total of 70 PEGs were performed. Patients had a mean age of 4 years and 3 months, and a mean weight of 12.2 kg at the time of performing the procedure. The mean anaesthetic time required for performing a PEG was 27 minutes. Fifty-four PEGs (77%) were performed for inability to swallow, 15 (21 %) to improve caloric intake, and 1 (1 %) for continuous enteral feeding. There were no deaths, 5 patients had major complications (6%), and 12 patients (17%) needed antireflux surgery subsequent to the placement of a PEG.Discussion. There is an increasing demand for PEGs at our institution. The indications for a PEG in this series are similar to those reported in other series, although we may be underutilising PEGs to improve caloric intake. Our complication rates compare favourably with those reported in other series. We have, however, identified post-PEG gastro-oesophageal reflux disease as a complication we would like to reduce, and suggest a practical approach to do so
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