Showing papers by "University of South Africa published in 1997"
TL;DR: The results indicated that the AIDS knowledge of South African street children was comparable to levels reported for groups of "hard-to-reach" youth in other parts of the world, and the relationships between power dynamics surrounding race and age were interpreted in terms of self-initiated controls over sexuality and sexual protection.
159 citations
TL;DR: A new method of seeding convective clouds for the purpose of augmenting rainfall is being developed in South Africa as mentioned in this paper, where flares are attached to the trailing edge of the wings of the seeding aircraft and ignited in updrafts below the cloud base of convective storms.
Abstract: A new method of seeding convective clouds for the purpose of augmenting rainfall is being developed in South Africa. Flares that produce small salt particles (0.5- mm mean diameter) are attached to the trailing edge of the wings of seeding aircraft and ignited in updrafts below the cloud base of convective storms. This method of delivery overcomes most of the difficulties encountered in the handling and the use of hygroscopic materials, difficulties that made seeding with ice nuclei (AgI) a more attractive option. The research that has led to the development of this new technique was prompted by an encounter with a storm with dramatically altered microphysics that was growing over a Kraft paper mill in the research area. Hygroscopic seeding flares were subsequently developed, and seeding trials began in October 1990. Successful seeding trials quickly led to the design and execution of a randomized convective cloud-seeding experiment, the results of which show convincing evidence of increases in the radar-measured rain mass from seeded storms when compared to the control or unseeded storms. Heightened reflectivities aloft seen by the real-time storm-tracking software and observed in the exploratory analysis raises the possibility of developing a radar-measured seeding algorithm that can recognize in almost real time a successful convective seeding event. The implications of such a development would have far-reaching effects on the conduct of future convective cloud-seeding experiments and operations. The authors’ seeding hypothesis postulates that the hygroscopic seeding at cloud base accelerates the growth of large hydrometeors in the treated clouds, which harvest more of the available supercooled water before it is expelled into the anvils by the strong updrafts that are a characteristic of the local storms, thereby increasing the efficiencyof the rainfall process. The validity of this hypothesis is supported by microphysical measurements made from an instrumented Learjet and the results of the randomized experiment, both of which are supported by numerical condensation‐coalescence calculations. There are also indications that the hygroscopic seeding may have an impact upon the dynamics of the treated storms, lengthening their lifetimes by strengthening the coupling of the updraft‐downdraft storm propagation mechanism. The apparent sensitivity of rainfall in convective clouds to the aerosol concentration, size, and chemical content may have climatic implications. Higher concentrations of small aerosols produced by pollution, biomass burning, etc., could adversely affect the efficiency of the rainfall process. The negative consequences of this effect would be magnified in regions that depend upon convective storms to provide the bulk of their annual rainfall.
144 citations
TL;DR: The important role of vertex partition problems, in particular the existence of uniquely partitionable graphs and reducible properties of graphs in this structure, is emphasized.
Abstract: In this paper we survey results and open problems on the structure of additive and hereditary properties of graphs. The important role of vertex partition problems, in particular the existence of uniquely partitionable graphs and reducible properties of graphs in this structure, is emphasized. Many related topics, including questions on the complexity of related problems, are investigated.
127 citations
TL;DR: In this article, the authors look at return on investment as a measure of profitability and some traditional and more recently developed working capital concepts as liquidity measures, and measure associations between profitability and the liquidity concepts by using chi-square analysis and stepwise forward regression.
Abstract: The two conflicting goals of working capital management are profitability and liquidity. This article looks at return on investment as a measure of profitability and some traditional and more recently developed working capital concepts as liquidity measures. Associations were measured between profitability and the liquidity concepts by using chi-square analysis and stepwise forward regression. The statistical test results showed that a traditional working capital leverage ratio, current liabilities divided by funds flow, displayed the greatest associations with return on investment. Well-known liquidity concepts such as the current and quick ratios registered insignificant associations whilst only one of the newer working capital concepts, the comprehensive liquidity index, indicated significant associations with return on investment.
105 citations
TL;DR: In this article, the authors measured the line width and spin-spin relaxation times of P1 and P2 centers in synthetic Ib and natural Ia diamonds with concentrations of P 1 and P 2 centers covering the range 0.03 - 400 atomic parts per million.
Abstract: Line widths and spin - spin relaxation times of P1 centres in synthetic Ib and natural Ia diamonds with concentrations of P1 and P2 centres covering the range 0.03 - 400 atomic parts per million have been measured. At concentrations higher than about ten atomic parts per million the line width is linearly dependent on the concentration. At lower concentrations the electron - dipolar contribution to the line width dominates and the width of the line remains constant. Since the pulse sequence employed for measurements eliminates the effects of inhomogeneous line broadening, of the line remains linearly dependent on the total paramagnetic impurity concentration, even at very low paramagnetic impurity concentrations.
103 citations
TL;DR: Despite scepticism about the viability, scope, and nature of liberatory psychology, a nuanced study of anti-apartheid and international progressive scholarship within psychology reveals otherwise as mentioned in this paper.
Abstract: Despite scepticism about the viability, scope and nature of liberatory psychology, a nuanced study of anti-apartheid and international progressive scholarship within psychology reveals otherwise. A...
92 citations
TL;DR: It is found that primiparous women are at risk of long-term weight gain because they gain the most weight during pregnancy, and high gestational weight gain is in itself a risk factor for long- term weight gain.
Abstract: SummaryThe independent associations between parity and maternal body mass index (BMI), and between parity and maternal weight gain, were investigated using a combination of cross-sectional and longitudinal analyses based on a retrospective, repeat-pregnancy study that examined the change in maternal body weight from the beginning of one pregnancy to the beginning of the next. A group of 523 multiparous women who had been weighed regularly during pregnancy, and none of whom had fallen pregnant less than 12 months after the birth of their previous child, were examined. Sociodemographic, behavioural, medical, obstetric and perinatal data, together with antenatal measurements of maternal body weight and height, were abstracted from each mother's obstetric notes. Parity was found to be independently associated with maternal BMI (p < 0·001), gestational weight gain (p < 0·001) and interpregnancy weight gain (p = 0·032). Women of different parities were found to be at differential risk of long-term weight gain f...
79 citations
TL;DR: To re-assess whether the changes in energy balance that accompany pregnancy predispose parous women to obesity, 71 longitudinal studies examined in the present review found body weight to be greater after pregnancy than it was before.
Abstract: The aim of this review was to re-assess whether the changes in energy balance that accompany pregnancy predispose parous women to obesity. A number of cross-sectional studies have sought to answer this question by examining the relationship between parity and maternal body weight. However, these studies were unable to control for the large number of sociobehavioural confounders that might be responsible for the apparent effect of parity on body weight. Longitudinal studies that examine changes in maternal body weight before and after regnancy avoid these problems by using each mother as her own control. Nevertheless, these studies have to overcome three methodological constraints: They must obtain an accurate measure of prepregnant body weight, they must give each mother sufficient time to lose any weight retained following delivery, and they must take into account the effect of ageing on maternal weight gain during pregnancy and the follow-up period. More than 90% of the studies reviewed found body weight to be greater after pregnancy than it was before (by 0.2-10.6 kg). and previous researchers who have examined the evidence for pregnancy-related weight gains suggest that body weight increases by an average of 04-4.8 kg following pregnancy. However, only three of the 71 longitudinal studies examined in the present review complied with the three methodological criteria. These studies concluded that mothers gain, on average, 0.9-3.3 kg more weight following pregnancy than nonpregnant controls, and that mean body weight remained 0.4-3.0 kg higher, even after controlling for a number of sociobehavioural confounders. This apparently modest increase in mean maternal body weight for women having one or two children conceals the fact that some mothers experience a substantial increase in body weight and become obese following pregnancy. It remains unclear whether these increases are simply the result of changes in energy metabolism during pregnancy and lactation, or whether they are influenced by inherent changes in lifestyle that accompany pregnancy and motherhood. Understanding the relative importance of these alternatives might help to explain the aetiology of maternal obesity."Clover was a stout motherly mare approaching middle life, who had never quite got her figure back after her fourth foal"George Well (1945) Animal Farm. London: Secker and Warburg.
46 citations
TL;DR: The local polynomial approximation of time-varying phase is used in order to estimate the instantaneous frequency and its derivatives for a complex-valued harmonic signal given by discrete-time observations with a noise.
Abstract: The local polynomial approximation of time-varying phase is used in order to estimate the instantaneous frequency and its derivatives for a complex-valued harmonic signal given by discrete-time observations with a noise. The considered estimators are high-order nonparametric generalizations of the short-time Fourier transform and the Wigner-Ville distribution. The asymptotic variance and bias of the estimates are obtained.
45 citations
TL;DR: In this paper, a synthesis of theoretical and analytical research frameworks in descriptive translation in South Africa is presented, providing a useful synthesis for comparative text analysis in the context of translation studies.
Abstract: Conventional research methods used in the social sciences or in the humanities fall short when applied to research in translation studies, which requires an interdisciplinary approach to comparative text analysis. This paper aims to fill this gap, providing a useful synthesis of theoretical and analytical research frameworks in descriptive translation in South Africa.
42 citations
TL;DR: In this paper, Ngokwasezidolophini apha eMzantsi Afrika, uvangontetho lweelwimi ezintanganye ngokokuskeyenzwa, lusetyenziselwa ikakhulu ukudala ubudlelane, hayi ukucekecana.
Abstract: Ukuxananaza kwemo yovangontetho kweelwimi ezilokishini eMzantsi Afrika kunye nobucukubhede malunga neemeko olusetyenziswa phantsi kwazo, kungaba neziphumo ezivuselela umdla omkhulu ukuba oku kunokuphononongwa ngo-kwesithako sikaMyers-Scotton se'markedness model' (ukusetyenziswa kwentetho ethile ngabom). Ngokwesi sithako izithethi ziyaliqonda ixabiso lokusetyenziswa kolwimi oluchanaba okuthile kwimo ethile yentlalo, zaye ziyakwazi nokuty-umba olona lwimi luchanekileyo ukudala unxibelelwano oluphuhlileyo nalowo kuthethwa naye. Ngokwasezidolophini apha eMzantsi Afrika, uvangontetho lweelwimi ezintanganye ngokokusetyenziswa, lusetyenziselwa ikakhulu ukudala ubudlelane, hayi ukucekecana. Ukulumisana ngolwimi kuthi kudiza ubuni bakho ngokolwimi, kube kusalatha kwakhona umoya wokuhlangabezana kwanentlonipho.
TL;DR: In this paper, the authors determined the fairness of the 1992 South African version of the Sixteen Personality Factor Questionnaire (16PF, SA92) for various groups and to contribute to the...
Abstract: The objective of this study was to determine the fairness of the 1992 South African version of the Sixteen Personality Factor Questionnaire (16PF, SA92) for various groups and to contribute to the ...
TL;DR: In this article, the 13C spin-lattice relaxation times for polarization in a field of 47 kG were measured for one type Ia diamond and one type IIa diamond.
TL;DR: Despite being freely available in English language translation since the late 1970s, the writings of Michel Foucault have only faintly imprinted themselves within the work of South African socio-me...
Abstract: Despite being freely available in English language translation since the late 1970s, the writings of Michel Foucault have only faintly imprinted themselves within the work of South African socio-me...
TL;DR: In this paper, a search towards 69 star-forming regions has led to the discovery of three new 4765-MHz excited OH masers, all of which are narrow linewidths and have constant widths and centroid velocities.
Abstract: A search towards 69 star-forming regions has led to the discovery of three new 4765-MHz excited OH masers. No 4750- or 4660-MHz excited OH masers were detected above a level of ∼ 1 Jy. The results of monitoring nine sources of 4765-MHz excited OH masers for periods of up to 7 yr are reported. Many of the linewidths are narrow and have had constant widths and centroid velocities throughout the monitoring period. The maser flux of one source was constant over 7 yr while in the most extreme case of variability the flux doubled in a period of 2 weeks.
TL;DR: In this article, the authors analyzed the effect of variation in protein content on the interpretation of quality data of advanced wheat lines and found a distinctive segregation between entries having higher (≥10%) and lower (<10%) flour protein contents for the three critical phases of commercial processing.
Abstract: The variation in the processing quality of South African winter wheat cultivars over growth environments is detrimental to its market value. Variation in protein content has previously been identified as a primary contributor to this variation and should therefore be considered in the interpretation of quality data presented during the cultivar release procedure. The aim of the study was to analyse such effects on the interpretation of quality data of advanced wheat lines. Our results indicated a distinctive segregation between entries having higher (≥10%) and lower (<10%) flour protein contents for the three critical phases of commercial processing. The incorporation of a range of localities where both protein levels are sufficiently represented, appeared to be of more importance than the number of harvest seasons over which the entry is evaluated. Finally, multivariate statistical techniques were used to compute user-friendly models for the objective characterisation of variation in milling and rheologi...
TL;DR: In this article, a mathematically rigorous method for solving three-atomic bound state and scattering problems is presented for applications in systems where the interatomic interaction is of a hard-core nature.
TL;DR: In this paper, the authors used a triangulation approach where a combination of quantitative and qualitative measurements were utilised and the results of both types of measurement integrated in the study of the construct.
Abstract: The research on employee-satisfaction was conducted in the manufacturing industry. The sample consisted of 543 employees. The methodology could be described as a "triangulation approach" where a combination of quantitative and qualitative measurements were utilised and the results of both types of measurement integrated in the study of the construct. The research confirms existing findings that although the measurement of dimensions such as equitable rewards, working conditions, supportive colleagues, job content, etc. yield results on the level of employee-satisfaction, a single question, namely, "How satisfied are you with your job?" compares favourably with the general index. The findings also suggest the advantage of complimenting the quantitative data with qualitative information. The conclusions confirm the value of a qualitative method in cross-cultural research in an African environment. Opsomming Die navorsing omtrent werknemerstevredenheid is uitgevoer in die vervaardigingsbedryf. Die steekproef het bestaan uit 543 werknemers. Die metode van ondersoek kan beskryf word as 'n "driekantige benadering" (triangulation approach) waar daar van kwantitatiewe en kwalitatiewe meting gebruik gemaak is en die resultate geihtegreer is in die bestudering van die konstruk. Die navorsing bevestig bestaande bevindinge dat die meting van dimensies soos vergelykbare belonings, werkstoestande, ondersteunende kollegas, inhoud van werk, ens. resultate lewer rakende die vlak van werknemerstevredenheid, 'n enkel vraag, naamlik, "Hoe tevrede is jy met jou werk?" gunstig vergelyk met die algemene indeks. Die bevindinge dui ook op die voordele van 'n benadering waar die kwantitatiewe data gekomplimenteer word deur kwalitatiewe inligting soos verkry uit individuele onderhoude. Die gevolgtrekkings bevestig die waarde wat die kwalitatiewe navorsingsmetode inhou vir kruis-kulturele navorsing in 'n Afrika konteks.
TL;DR: The role of hydrogen bonding in the cuticular wax of Hordeum vulgare L. has been investigated by comparing differential scanning calorimetry and X-ray powder diffraction results of the wax with those of n-alkane mixtures with chain-length distributions resembling that of the plant wax as discussed by the authors.
Abstract: The role of hydrogen bonding in the cuticular wax of Hordeum vulgare L. has been investigated by comparing differential scanning calorimetry and X-ray powder diffraction results of the wax with those of n-alkane mixtures with chain-length distributions resembling that of the wax. It is concluded that hydrogen bonding prevents separation of the short and long chain-length distributions and results in the formation of an amorphous component which is large compared with that of a typical paraffinic wax. It seems that the longer ester chains (39 ≥n≥ 50) bridge the amorphous zone containing chain-ends between two adjacent layers of shorter chains (20 ≥n≥ 33), where n is the number of carbon atoms per chain. In contrast to a paraffinic wax, which has a monolayered structure, this plant wax has a bilayered structure.
TL;DR: This investigation shows that M. furfur antigens can sensitize the host, mainly the oval yeast form of M.fur with a very important specific IgG response in patients with SD and PV.
Abstract: Humoral immune responses against exoantigen components of oval, elliptic and round yeast forms of Malassezia furfur were analysed by ELISA and Western blotting assays, using sera from patients with pityriasis versicolor (PV), seborrheic dermatitis (SD) and healthy adults (HA), as control. Sera from patients with SD showed IgG anti-oval M. furfur titers ranging from 1/400 to 1/6400 showing geometric mean (GM) of 1/1472, higher than those obtained with sera from patients with PV (1/200 to 1/6400, GM = 1/1239). Both patient groups showed mean titres statistically superior (P < 0.05) than those obtained form HA (GM = 1/229). Similar data were also obtained with the elliptic and round antigens. However, the anti-oval IgG mean titers from patients' sera were much higher than those obtained with elliptic or round antigenic components (p < 0.05) Anti-M furfur IgM titers obtained from patient's sera with PV against all three exoantigens were statistically superior (p < 0.05) than HA group. Patients with SD showed IgM titers statistically superior (p < 0.05) only to oval yeasts of M. furfur. The IgA mean titers from patients' groups against the different morphological antigens were shown be slightly higher than those HA group. By Western blot, using rabbit anti-sera, the different antigenic components of M.furfur showed a close relationship mainly between oval and elliptic yeast cells antigens. The 70 kDa component of the M. furfur exoantigen of oval morphology was recognized by 84% of the PV patients' sera. On the other hand, SD patients' sera recognized 3 principal components of 70 kDa (100%), 65 kDa (67%) and 84 kDa (53%). These components may be considered immunological markers for PV and SD. Twenty-five percent of HA sera recognized the components of 65, 70 and 94 kDa. This investigation shows that M. furfur antigens can sensitize the host, mainly the oval yeast form of M. furfur with a very important specific IgG response in patients with SD and PV.
TL;DR: It is proved that the smallest cardinality among the maximal irredundant sets in an n–vertex graph with maximum degree Δ(≥2) is at least 2n/3Δ.
Abstract: It is proved that the smallest cardinality among the maximal irredundant sets in an n–vertex graph with maximum degree Δ(≥2) is at least 2n/3Δ. This substantially improves a bound by Bollobas and Cockayne [1]. The class of graphs which attain this bound is characterised.
TL;DR: The findings of this study are in agreement with previous reports using other classes of antihypertensive drugs that also failed to detect any tendency for increases in nocturnal respiratory disturbance indices over assessment periods of 8 weeks or shorter.
TL;DR: In this article, the authors postulate that creativity is a state of being that is challenged by the socialization process in Western civilization, and they envisage two differing states of being namely, an essential and a conventional.
Abstract: SUMMARY
Because of misperceptions about the nature of creativity, many creative children are misunderstood in and out of their classrooms. Based on a close association with creative adults and childrenn, the authors postulate that creativity is a state of being that is challenged by the socialization process in Western civilization. The authors envisage two differing states of being namely, an essential and a conventional. These states represent end points on a continuum. Creative adults speak of their struggle to try and regain something of their original state of being. Understanding creative children who are closer to the essential state is important for their emotional well-being and the nurturing of their creativity.
TL;DR: In this article, a mathematically rigorous method suitable for bound-state and scattering process calculations for various three-atomic or molecular systems where the underlying forces are of a hard-core nature is presented.
Abstract: We present a mathematically rigorous method suitable for bound-state and scattering process calculations for various three-atomic or molecular systems where the underlying forces are of a hard-core nature. We employed this method to calculate the binding energies and the ultra-low-energy scattering phase shifts below as well as above the breakup threshold for the three-He-atom system. The method has proved to be highly successful and suitable for solving the three-body bound-state and scattering problem in configuration space and thus it paves the way to study various three-atomic systems, and to calculate important quantities such as the cross sections, recombination rates, etc. {copyright} {ital 1997} {ital The American Physical Society}
TL;DR: It is shown that Qn possesses minimal dominating sets of cardinality 5n 2 − O (1) and that the cardinality of any irredundant set of vertices of Qn(n ⩾ 9) is at most ⌊6n+6−8√ n+√n+1⌋.
TL;DR: In this article, a global spacetime evolution algorithm based on a Cauchy initial-value formulation in a bounded interior region and based on characteristic hypersurfaces in the exterior is proposed.
Journal Article•
TL;DR: The role of the traditional healer is an important one one not likely to be changed and one amenable to training and the identification of the difficulties in training is concluded.
Abstract: From the data collected during qualitative research, in 1995, to determine the possibility of collaboration with traditional healers a number of themes were highlighted. The different types of traditional healers, the way in which they operate as well as the importance of collaboration was identified. In this article the contributions of traditional midwives in rendering health care, especially in the rural areas in the Northern Cape and the Free State will be discussed. The data was collected during interviews and observations, done over a period of seven months. When the respondents could not speak English or Afrikaans an interpreter was used. Interviews were also conducted with health care staff and patients. The contributions of the traditional midwives are of utmost importance and should not be discouraged. With the necessary training the traditional midwives could help in providing an effective and efficient health service to pregnant women. Traditional midwives have been an integral part of African medicine for centuries. This is not only because African people still love and fear the spirits, but also because a great number of the South African population do not have access to existing health services. This is especially so in the rural areas and informal settlements. According to the Reconstruction and Development Programme (RDP) of the Government of National Unity it is important that everyone who could make a contribution towards the provision of health care should be involved. This view is supported in the ANC Health Plan and a Policy Document for the Development of a District Health System for South Africa, where it is stated that traditional healers (traditional midwives are included in this category) could play a role in the delivery of health care. The research on which the article is based was done to determine the role traditional healers could play in collaboration with primary health care services. In this article only the role of the traditional midwife will be discussed.
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TL;DR: The notion of truth pervades the very fibre of Western thinking as discussed by the authors, and the question of the end of religious, scientific, and metaphysical truth is addressed in the context of the Truth and Reconciliation Commission.
Abstract: As we are approaching the end of the century, many ideas, systems, and certainties, previously taken for granted, seem to be questioned, altered and rejected. One of these is the notion of truth, which pervades the very fibre of Western thinking. Rejecting the relevant critique as simply a postmodem fad, this article proceeds to give attention to the questions regarding the end of religious, scientific, and metaphysical truth. Truth and power are dealt with, as well as the narrative nature of truth. The article concludes with reference to the functioning of truth in the South African context as manifested in the Truth and Reconciliation Commission.
TL;DR: In this article, the corporation from a liberal-capitalist point of view is criticised, arguing that incorporation violates the right and responsibilities of private ownership, and some disadvantages connected to the proposed repeal of incorporation for private enterprise are discussed.
Abstract: The paper criticizes the corporation from a liberal-capitalist point of view, arguing that incorporation violates the right and responsibilities of private ownership. Aspects of current capitalist practice which popularly concentration, speculative instability and excessive growth/profit orientation) are traced back to the corporate form rather that to genuinely capitalist institutions such as private property and free exchange. Some disadvantages connected to the proposed repeal of incorporation for private enterprise are discussed.
TL;DR: The authors argue that programmatic anti-racist interventions such as this Special Issue are crucial to the process of redressing the "racialised" patterns of research and authorship characterising mainstream psychology journals.
Abstract: This ‘article’ serves as introduction to the Special Issue: black scholarship. As such, it outlines the various articles contained in, as well as the rationale for the issue. In this article the authors argue that programmatic anti-racist interventions such as this Special Issue are crucial to the process of redressing the ‘racialised’ patterns of research and authorship characterising mainstream psychology journals.