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Inleiding tot die eksperimentele Sielkunde
No full textPhilosophiae Doctor - PhDElke skolier wat rue tevrede is om dit op skool slegs met lepels in te kry nie, het seker al gewonder hoe kennis oorspronklik verkry word. In daardie stadium is ons gewoonlik nog tevrede om die feite wat die onderwyser aan ons voorlê, of wat ons in die boeke gelees het, op gesag aan te neem. Maar selfs dan toets ons dikwels daardie gesag deur gewone en terloopse waarnemings. Byvoorbeeld: in die fisika leer ons dat as ons 'n groot en 'n klein klippie gelyktydig van enige hoogte laat val, hulle ook gelyktydig op die aarde sal beland as daar nie met die een klip intussen iets gebeur het wat nie met die ander klip gebeur het nie: met ander woorde as aIle faktore gelyk gebly het. Toe ons van
hierdie gelyk-vallende klippies gehoor het, het party van ons op 'n dubbelverdieping gebou, of selfs op die dak van die buitegebou, opgeklim en die twee klippies self laat val om na te gaan of dit werklik so was. En hiermee het ons 'n eenvoudige eksperiment uitgevoer om te toefs of die hennis wat ons geleer het wel reg was. Dit was 'n eenvoudige eksperiment omdat die invloed van die lugdruk, en van die wind wat waai en 'n groter uitwerking op die groot klip het as op die klein klippie, buite rekening gehou is by die waarneming. Ons het ook net van ons oë gebruik gemaak om te kyk of die twee klippe gelyktydig op die aarde beland. Maar as ons middels kon aangewend het om die invloed van die genoemde twee faktore te bepaal, sou dit 'n meer presiese eksperiment gewees het en nie 'n terloopse waarneming nie. Sulke presiese eksperimente word in die laboratorium uitgevoer met die doelom betroubare kennis te kry. Die soort wetenskaplike kennis wat ons op skool leer, is reeds in die verlede deur navorsers vasgestel, en hulle bevindings is nou beskikbaar vir ons in teksboeke. Hulle eksperimente was bedoel om op nuwe kennis uit te kom. Maar die student wat sy verstand gebruik is nie noodwendig tevrede met gesag nie; hy wil self graag eksperimente maak om te sien of wat die gesag beweer werklik so is. Sy eksperimente is bedoel om eerstens te toets of die ander navorsers se resultate reg is, en tweedens 0111 hom oefening te gee met die uitvoering van eksperimente. Navorsers werk op wetenskaplike manier om nuwe kennis te verkry. Dit word vertel dat Newton S)' idee van die aantrekkingskrag van die aarde gekry het toe hy 'n appel sien val het, en dat Archimedes die idee van sy wet: dat voorwerpe in water van hulle gewig verloor, en dat die gewig wat daardie voorwerpe verloor gelykstaan aan die gewig van die volume water wat deur die voorwerpe verplaas word, gekry het terwyl hy besig was om te bad. Waarheid is dat albei allank besig was om oor hulle probleme na te dink en na te soek, en dat toe Newton die appel sien val het en Archimedes die gedagte in die. bad gekry het, dit feite was wat by vorige kennis aangesluit het. Hulle was egter nie daarmee alleen tevrede nie; daarna het albei die gedagte gaan toets .met wetenskaplike proefnemings om op kennis uit te kom. Die proefnemings en wetenskaplike navorsing kan jare en jare se harde werk vereis het. Om die eerste atoombom te laat ontplof het tientalle wetenskaplikes en duisende geskoolde assistente en werksmense jare se werk gekos. So het dit ook baie jare geverg om vas te stel dat mense wat siek word nie getoor is nie maar dat, byvoorbeeld, kieme 'n groot rol kan speel byeen of ander siekteverskynsel; en dit weer het ons aan die wetenskaplike navorsingsmetodes van 'n Pasteur te danke. Die verslag valt wetenshaplilu: navorsers se werk is nou ons wetenskaplike literatuur. Hierdie mense wat 'n eksperiment vir die eerste keer gemaak het, het dit nie gedoen om te toets of ander mense se feite korrek is nie, maar om uit te kom op oorspronklike
feite van hul eie. In die Sielkunde is die basis vir die metodes van ondersoek dieselfde as vir ander wetenskappe. Daar is die noodsaaklikheid om deur middel van wetenskaplike proefneming op nuwe kennis uit te kom. Om dit te kan doen moet 'n mens eers leer hoe om 'n proefneming in te rig en moet jy voldoende oefening kry met proefnemings. As studente is dit vir ons 'n vereiste om die verskillende verskynsels self te kan ondersoek en later miskien self op nuwe kennis uit te kom en, wie weet, self een of ander oorspronklike bydrae te maak. Maar dan moet ons weet hoe om 'n eksperiment of ondersoek uit te voer. Om dit geleerd te stel: Ons moet die objektiewe metodes van 'n wetenskaplike eksperiment beheer; ons moet weet hoe om 'n proefneming in te rig
Dental caries clinical and experimental investigations
No full textMagister Scientiae Dentium - MSc(Dent)pental caries is the most prevalent of all diseases among civilized peo_ple. ~_n_ol
middl~~-~o=~ay with ~full c§rfectly healthy tee!h. From various statistics obtained
ffo·m- practically every country in the world, the incidence is estimated to be over 95 per cent. By this is meant
that more than 95 ont of every 100 persons suffer or have suffered at some time from one or more carious teeth.
Statistics are based mostly on dental examinations of school children, because of the obvious difficulty of examining
large groups of adults for dental defects. There is a lamentable lack of reliable and accurate statistics concerning
the incidence of dental caries in most civilized countries.
Klein and Palmer (1938) reported that the incidence of dental caries (as defined above) among elementary
school children in the United States is 95 per cent. Day and Sedwick (1935) found the incidence among Rochester
(N.Y.) schoolchildren to be 99 per cent. The final report of the Mixed Committee of the League of Nations
of 1937 shows that in Norway, of 25,000 school children examined, only 160 possessed perfect sets of teeth, or
99 per cent. affected by dental caries. Day and Sedwick (1935) state that, in the county of Shropshire in England,
97 per cent. of the children at the age of 12 had dental caries. The Director-General of Health of New Zealand,
in .his annual report of 1941, states that of 52,500 children examined, 95 per cent. were affected by caries: In
India, Day and Tandan (1940) reported that the incidence of dental caries among urban children in Labore was
94 per cent. In South Africa, Friel and Shaw (1931) found 93 per cent. of urban children suffering from dental
caries. Staz (1938) reported that of 300 European adults examined in Johannesburg none showed caries-free
mouths
A Grammar of Baca and its relation to Swazi, Zulu and Xhosa
No full textMagister Artium - MAThe material for this work is based" on field work conducted during three. weeks in February and two weeks in September, 1941. Both periods were spent at Lourdes in East Griqualand, a place well suited for a place well suited for the purpose, being the centre of an area inhabited by the Baca people. The only other important area is round Mount Frere. I am indebted to Reverend Father Jakob for his
assistance at Lourdes, to Mr L, I. Venable s and Mr. J. A. Campbell, both of the Johannesburg Municipal Native Affairs Department, for their courtesy in placing Baca speakers at my disposal, to Mr. l. A.H Mulcahy of the Main Pass Office , and Mr. A. G. T. Chaplin of the Swaziland. Government office, for their kind assistance in relation to Swazi, and. to the Inter-University Committee for African Studies for a grant for carrying out the necessary field wor
Girl champ in eSwatini: A strategic marketing campaign to promote demand for sexual and reproductive health services among young women
No full textEfforts to engage adolescent girls and young women (AGYW) in HIV services have struggled, in part, due to limited awareness of services and stigma. Strategic marketing is a promising approach, but the impact on youth behavior change is unclear. We report findings from a mixed methods evaluation of the Girl Champ campaign, designed to generate demand for sexual and reproductive services among AGYW, and piloted in three clinics in the Manzini region of eSwatini. We analyzed and integrated data from longitudinal, clinic-level databases on health service utilization among AGYW before and after the pilot, qualitative interviews with stakeholders responsible for the implementation of the pilot, and participant feedback surveys from attendees of Girl Champ events. Girl Champ was well received by most stakeholders based on event attendance and participant feedback, and associated with longitudinal improvements in demand for HIV services. Findings can inform future HIV demand creation interventions for youth
Learning with technology in physiotherapy education: Design, implementation and evaluation of a flipped classroom teaching approach
No full textThe purpose of the study was to describe the design, implementation and evaluation of a flipped
classroom teaching approach in physiotherapy education. The flipped classroom is a blended learning approach in
which students receive digital lectures as homework, while active learning activities are used in the classroom.
Flipped classroom teaching enables a learning environment that aims to develop higher-order cognitive skills. The study design was a historically controlled, prospective, cohort study. An eight week theoretical
course on musculoskeletal disorders was redesigned, moving from a conventional approach to a flipped classroom
model. Pre-class learning material consisted of about 12 h of video lectures and other digital learning resources that
were split up over the duration of the course. In-class activities consisted of seven full-day seminars where students
worked in groups in order to solve problem-based assignments. The assignments were designed to reflect
authentic clinical problems and required critical thinking and reasoning. Outcomes were measured with coursegrades
and compared with historical controls of conventional teaching, using descriptive statistics. Self-perceived
learning outcomes and students’ experiences were also collected in a survey
Protecting animals from mistreatment through private prosecutions in South Africa: A comment on National Society for the Prevention of Cruelty to Animals v Minister of Justice and Constitutional Development 2016 1 SACR 308 (SCA)
No full textThis article has been accepted for publication and will appear in a revised form, subsequent to peer review and/or editorial input by Cambridge University Press, in Journal of
African Law published by Cambridge University Press.In South Africa, the general rule is that when an offence is committed, the suspect has to be prosecuted by a public prosecutor. This is on the basis of the Constitution (section 179) and the National Prosecuting Authority Act (section 20). However, there is an exception to this general rule - where a victim of crime or his or her representative, where the victim has no legal capacity, is permitted to institute a private prosecution if the prosecutor has declined to prosecute.International Bibliography of Social Science
Inhibition of HIV-1 enzymes, antioxidant and anti-inflammatory activities of Plectranthus barbatus
No full textEthnopharmacological relevance: Plectranthus barbatus is widely used in African countries as an herbal
remedy to manage HIV/AIDS and related conditions.
Aim of the study: To investigate the HIV-1 inhibitory, anti-inflammatory and antioxidant properties of P.
barbatus and thereby provide empirical evidence for the apparent anecdotal success of the extracts.
Materials and methods: Ethanolic extract of P. barbatus's leaves was screened against two HIV-1 enzymes:
protease (PR) and reverse transcriptase (RT). Cytotoxicity of the extract was determined through
measuring tetrazolium dye uptake of peripheral blood mononuclear cells (PBMCs) and the TZM-bl cell
line. Confirmatory assays for cytotoxicity were performed using flow cytometry and real-time cell
electronic sensing (RT-CES). The free radical scavenging activity of the extract was investigated with 2,2-
diphenyl-1-picrylhydrazyl while the anti-inflammatory properties of the plant extract were investigated
using a Th1/Th2/Th17 cytometric bead array technique
Feature Reduction for the Classification of Bruise Damage to Apple Fruit Using a Contactless FT-NIR Spectroscopy with Machine Learning
No full textSpectroscopy data are useful for modelling biological systems such as predicting quality parameters of horticultural products. However, using the wide spectrum of wavelengths is not practical in a production setting. Such data are of high dimensional nature and they tend to result in complex models that are not easily understood. Furthermore, collinearity between different wavelengths dictates that some of the data variables are redundant and may even contribute noise. The use of variable selection methods is one efficient way to obtain an optimal model, andthis was the aim of this work. Taking advantage of a non-contact spectrometer, near infrared spectral data in the range of 800–2500 nm were used to classify bruise damage in three apple cultivars, namely ‘Golden Delicious’, ‘Granny Smith’ and ‘Royal Gala’. Six prominent machine learning classification algorithms were employed, and two variable selection methods were used to determine the most relevant wavelengths for the problem of distinguishing between bruised and non-bruised fruit. The selected wavelengths clustered around 900 nm, 1300 nm, 1500 nm and 1900 nm. The best results were achieved using linear regression and support vector machine based on up to 40 wavelengths: these methods reached precision values in the range of 0.79–0.86, which were all comparable (within error bars) to a classifier based on the entire range of frequencies. The results also provided an open-source based framework that is useful towards the development of multi-spectral applications such as rapid grading of apples based on mechanical damage, and it can also be emulated and applied for other types of defects on fresh produce