Groepsbenadering in die bedryfspsigologie*

Gedurende die ontwikkeling van enige vakwetenskap word gewoonlik aksentverskuiwinge aangetref, en as dit ’n toegepaste vakwetenskap is, wat moet tred hou met die ontwikkelinge in die praktyk, kan sulke aksentverskuiwings geweldig groot wees

Labour conflict and the persistence of macro underemployment in South Africa

Something must be structurally wrong in a labour market when a well developed economy like that of South Africa is not able to absorb and allocate an accumulating surplus of labour over a period of 20 years or longer but has instead moved to the use of more capital-intensive technology. The objective of this paper is to analyse the role labour conflict plays in the persistence of macro underemployment in South Africa. For the analysis two models identified from the literature were used. In these models labour conflict originates from an over-regulated labour market where labour appropriates capital and bad or hostile labour relations. In both models the switch to technology leads to underemployment. It was found that bad labour relations contribute to the persistence of underemployment in South Africa

Cone beam computed tomography volumetric airway changes after orthognathic surgery:a systematic review

The aim of this systematic review was to provide a structured overview of three-dimensional airway volume changes in relation to various orthognathic surgeries. Clinical human studies performing pre- and postoperative three-dimensional airway volume assessments to investigate volumetric changes of the airway after orthognathic surgery were included. Pre-determined inclusion and exclusion criteria were applied in an extensive search of the PubMed, Embase, and Web of Science electronic databases. The cut-off date was set to January 1, 2022. Forty-one articles reporting retrospective and prospective case–control and case series studies were included. All studies were determined to be of medium quality (moderate risk of bias). The included studies were categorized by type of intervention. Pre- and postoperative volumes were extracted from the available data, and volume changes as a percentage of the preoperative levels were calculated. Isolated mandibular setback surgery generally decreased the airway volume. Isolated maxillary or mandibular advancement, bimaxillary advancement, and surgically assisted maxillary expansion generally increased the airway volume in the total airway and oropharynx, among which the effect of bimaxillary advancement surgery appeared most significant. High heterogeneity exists in the terminology and definitions of the airway and its segments. A more uniform methodology for airway volume measurement is needed to provide an insight into the impact on the airway of specific types of surgical intervention. In conclusion, airway volumes are affected after orthognathic surgery, which may be of clinical significance, especially in patients who are predisposed to obstructive sleep apnoea

South African National Land-Cover Change Map

Globally, countries face a changing environment due to population growth, increase in agricultural production, increasing demand on natural resources, climate change and resultant degradation of the natural environment. One means of monitoring this changing scenario is through land-cover change mapping. Modern Earth Observation (EO) technologies, especially those EO datasets comprising a multi-year data archive, lend themselves to land-cover change studies. This project used a practical and cost-effective approach for monitoring land-cover change at a national scale over time using EO data. The primary objective of this study was to determine the extent of transformed landscape change within South Africa over a 10-year period between 1994 and 2005. The project used three generalised land-cover datasets (for 1994, 2000 and 2005) and quantified the change between these assessment years. The land-cover change was based on five classes: Urban, Mining, Forestry, Cultivation and Other. The standardised five class land-cover datasets representing the three assessment years were compared within a uniform national grid, based on 500 m x 500 m cells. The land-cover allocated to each cell in each year represented the spatially dominant land-cover within that cell, as  determined from the original land-cover datasets. Various spatial modelling procedures were used to ensure compilation of comparable and standardised land-cover class allocations to each cell for each year, prior to any year-on-year change analyses. The results indicate that at a national level there has been a total increase of 1.2% in transformed land  specifically associated with Urban, Cultivation, Plantation Forestry and Mining. This represents an increase from 14.5% transformed land in 1994 to 15.7% in 2005 across South Africa

Die generasie-interval, van die Suid-Afrikaanse vleismerino

The average generation interval of 3,53 years in S.A. Mutton Merino stud flocks in l96ll62 is the result of an average ram-age of 3,57 year sa nd an ewe-agco f 3,49 year s .I n 1971/72 the averagc 'agoef rams and ewesw as 3,86 and 4.13 year sr espec t i vel yw i th an averageg enerat ion interval of ' 4,00 years"T he e>l tendingo f the generat ioni nterval is mainly a resul to f an mcreaseo f 0,64 yearsi n the average age of ewes. The niost important factors leading to thc iatter are a smallcr annual replacement of ewes and the first mating of young ewes at a later age. The generation interval of difierent strata of thc breeding structure could not show a clear relationship between generation interval end the relative imporlanr-e of the flock.Die gemiddelde generasie- intervavia n 3,53 Jaar van S.A. .V leismer inostoetkuddesin l96l /62 is die resul taatv an'n genuddelde ramouderdorn van 3,57 jaar en"n ooioud,;rdonr van -r,49 jaar. In l97 ll72 was die gemiddelde ouderdom van ramme en ooie 3,86 e'n 4,13 jaar onderskeidel ikm et 'n gemiddeldeg cnerasre- intervavla n 4.00 jaar . Dic ver lengingv an die generasie- intervaisl hoofsaakl ikd ie gevolg van 'n toename van 0,64 Jaar rn die gcnriddelde ouderd()m van ooie. Die belangrikste faktore wat hiertoe gelei het is'n kleiner jaarlikse ooiverplasing en die eerstc paring van jong i,roic op 'ir lrrter ouderdom. Diegenerasie-interval van verskillende strata in die teeltstruktuurkon nie 'n duidelike verband tusren senerasie-interval en relatiewe belansrikheid van die kudde aandui nie

Self-tuning curing oven control

Abstract: Certain modern materials used in manufacturing require a specific temperature profile during the curing process to produce the desired characteristics (such as hardness). Classically, to obtain optimum control of an oven, a series of trials should be embarked on to accurately determine the coefficients of the regulator. This paper proposes a method to automatically determine the optimum parameters of the controller during the first heating process. The method has been implemented and validated in a small curing oven (3 kW). The step response and steady state error obtained were acceptable

Influence of high-protein and high-carbohydrate diets on serum lipid and fructosamine concentrations in healthy cats

Objectives: The aim of this study was to determine whether high-protein and high-carbohydrate diets exert differential effects on serum cholesterol, triglyceride and fructosamine concentrations in healthy cats. Methods A randomised, crossover diet trial was performed in 35 healthy shelter cats. Following baseline health assessments, cats were randomised into groups receiving either a high-protein or high-carbohydrate diet for 4 weeks. The cats were then fed a washout diet for 4 weeks before being transitioned to whichever of the two studied diets they had not yet received. Fasting serum cholesterol, triglyceride and fructosamine concentrations were determined at the end of each 4-week diet period. Results Cats on the high-carbohydrate diet had significantly lower serum cholesterol ( P 5) had lower cholesterol ( P = 0.007) and triglyceride ( P = 0.032) concentrations on the high-protein diet than cats within other BCS groups. Conclusions and relevance Diets higher in protein and lower in carbohydrates appear beneficial for short-term glucose control in healthy cats. A high-protein diet was associated with significantly elevated cholesterol and triglyceride concentrations in healthy cats, even though the increase was significantly less pronounced in cats with a BCS >5. This finding suggests that overweight cats process high-protein diets, cholesterol and triglycerides differently than leaner cats

Cancer genetics: An approach to suspected hereditary breast or colorectal cancer

Two of the most common cancers are breast cancer and colorectal cancer. Up to 10% of cases of each are associated with a high risk of recurrence in an affected individual, or of occurrence in biological relatives. This results from the presence of an underlying mutation (or ‘pathogenic variant’) in a high-penetrance gene. Such cases are typically associated with an autosomal dominant pattern of inheritance, although this may not be obvious in the family history. Genetic testing can identify many (but not all) of these cases, and should be offered to those whose family history or clinical features suggest a high risk. Although testing for certain risk genes (e.g. BRCA1 or BRCA2) has been available for years, the advent of next-generation sequencing ‘gene panels’ now allows for simultaneous testing of many more genes at lower cost. This allows for more frequent detection of pathogenic variants in underlying genes than in the past, but also makes interpretation more complex. An index of suspicion for genetic cancers and appropriate referral to a genetics health professional are increasingly important