Cross sections of proton-induced reactions on 152Gd, 155Gd and 159Tb with emphasis on the production of selected Tb radionuclides

Cross sections are presented for various Dy, Tb and Gd radionuclides produced in the proton bombardment of 159Tb as well as for the reactions 152Gd(p,4n)149Tb and 155Gd(p,4n)152Tb up to 66 MeV. The experimental excitation functions are compared with theoretical predictions by means of the geometrydependent hybrid (GDH) model as implemented in the code ALICE/ASH, as well as with values from the TENDL-2012 library and previous literature experimental data, where available. Physical yields have been derived for the production of some of the medically important radioterbiums, namely 149Tb (radionuclide therapy), 152Tb (PET) and 155Tb (SPECT). The indirect production of high-purity 155Tb via the decay of its precursor 155Dy is reported. The possibility of a large-scale production facility based on a commercial 70 MeV cyclotron is also discussed

Spectroscopic studies of hydrogen plasmas in a magnetic well

Experiments are described in which the containment times of plasmas in Andreoletti's modified theta-pinch apparatus are increased by the addition of an external D.C. field produced by a modified version of the "Tennis Ball Seam" conductor described by Larkin. The diagnostics used are all spectroscopic

An investigation into cases of suspected poisoning in Africans in Northern Rhodesia

No Abstract

Further developments in the treatment of poisoning with alkylphosphate (Organophosphate) insecticides

No Abstract

Suid-afrikaanse musiekwoordeboek/south african music dictionary.

Reino Ottermann en / and Maria Smit, Hoofredakteurs / Chief editors, bygestaan deur / assisted by Izak Grové, Winfried Lüdemann, Hein-rich van der Mescht en / and Caroline van Niekerk. Suid-Afrikaanse Musiekwoordeboek/South African Music Dictionary. Tweede, hersiene en vermeerderde uitgawe/Second, revised and enlarged edition. 2000, 296 pp. ISBN 1-86890-019-3. Kaapstad/Cape Town: Pharos. Prys/Price: R69.95

A scaling analysis of ozone photochemistry

International audienceA scaling analysis has been used to capture the integrated behaviour of several photochemical mechanisms for a wide range of precursor concentrations and a variety of environmental conditions. The Buckingham Pi method of dimensional analysis was used to express the relevant variables in terms of dimensionless groups. These grouping show maximum ozone, initial NOx and initial VOC concentrations are made non-dimensional by the average NO2 photolysis rate (jav) and the rate constant for the NO?O3 titration reaction (kNO); temperature by the NO?O3 activation energy (ENO) and Boltzmann constant (k) and total irradiation time by the cumulative jav?t photolysis rate. The analysis shows dimensionless maximum ozone concentration can be described by a product of powers of dimensionless initial NOx concentration, dimensionless temperature, and a similarity curve directly dependent on the ratio of initial VOC to NOx concentration and implicitly dependent on the cumulative NO2 photolysis rate. When Weibull transformed, the similarity relationship shows a scaling break with dimensionless model output clustering onto two straight line segments, parameterized using four variables: two describing the slopes of the line segments and two giving the location of their intersection. A fifth parameter is used to normalize the model output. The scaling analysis, similarity curve and parameterization appear to be independent of the details of the chemical mechanism, hold for a variety of VOC species and mixtures and a wide range of temperatures and actinic fluxes

Challenges Influencing the Professional Context of the Foundation Phase Teachers in Rural and Township Schools in South Africa

South Africa is one of the most unequal societies in the world (Breetske, 2018), which also is visible in the schooling system, ranging from private, inner-city, township and rural schools. The general perception is that there is an ongoing crisis in South African education, and that the current system is failing the majority of South African’s youth (Spaul, 2013). There is worldwide consensus that the quality of education should already be addressed in the foundation phase, spanning the first three years of formal education. This article explores the perceptions of 282 foundation phase teachers predominantly in rural and township schools on various aspects regarding the education system. Using the theoretical framework of Mockler (2011) to assess teacher professional identity, the first dimension of teacher identity, namely personal experience, was used as lens to conduct the empirical study. Four themes emerged, namely competence, relationships, school context and challenges. Findings indicate that foundation phase teachers in general have positive attitudes towards various education related matters, but their perceptions were associated with the types of schools where they were teaching. Lack of resources and overcrowded classrooms were highlighted as manifestations of inequality.Group C: Teacher Professional Developmen

A scaling analysis of ozone photochemistry: I Model development

International audienceA scaling analysis has been used to capture the integrated behaviour of several photochemical mechanisms for a wide range of precursor concentrations and a variety of environmental conditions. The Buckingham Pi method of dimensional analysis was used to express the relevant variables in terms of dimensionless groups. These grouping show maximum ozone, initial NOx and initial VOC concentrations are made non-dimensional by the average NO2 photolysis rate (jav) and the rate constant for the NO-O3 titration reaction (kNO); temperature by the NO-O3 activation energy (ENO) and Boltzmann constant (k) and total irradiation time by the cumulative jav?t photolysis rate (?3). The analysis shows dimensionless maximum ozone concentration can be described by a product of powers of dimensionless initial NOx concentration, dimensionless temperature, and a similarity curve directly dependent on the ratio of initial VOC to NOx concentration and implicitly dependent on the cumulative NO2 photolysis rate. When Weibull transformed, the similarity relationship shows a scaling break with dimensionless model output clustering onto two straight line segments, parameterized using four variables: two describing the slopes of the line segments and two giving the location of their intersection. A fifth parameter is used to normalize the model output. The scaling analysis, similarity curve and parameterization appear to be independent of the details of the chemical mechanism, hold for a variety of VOC species and mixtures and a wide range of temperatures and actinic fluxes

A scaling analysis of ozone photochemistry: II Investigation of the similarity relationship

International audienceThe similarity relationship for maximum ozone concentration as a function of initial precursor concentrations developed in the first article of this 2-part series exhibits a scale break, most easily seen after a Weibull transformation, which identifies a characteristic scale for ozone photochemistry. In this paper, we investigate the similarity relationship using simple semi-quantitative models and model output. From this investigation, we develop a set of properties characterizing ozone-precursor relationships. We find the scaling break is associated with a change in the temporal variability of ozone production. Finally, we examine a series of smog chamber experiments for evidence of a scaling break. We find the data support a slight break after suitable transformation. It is difficult to tell if the lack of distinct break is due to smog chamber experimental limitations, a bias in the test conditions or if the processes leading to the scaling break are overly enhanced by chemical mechanisms

The value-added statement: An appeal for standardisation

Owing to the absence of accounting standards for the preparation of a value-added statement (VAS), a large variety of methods are used in financial statements. In this study the published value-added statements (PVAS) of companies listed on the JSE Securities Exchange during the period 1976-2005 have been standardised by the Graduate School of Business of the University of Stellenbosch (USB) in order to quantify the differences between the standardised VAS (SVAS) and the PVAS. These differences consist of the inclusion of items that do not belong in the VAS, items that are erroneously allocated among the distribution to stakeholders, and interpretation differences in whether a certain item forms part of the calculation of value added or the distribution thereof. The greatest difference quantified was the overstatement of the distribution to government that amounted to 54.4% of total differences. For users, including government, to properly calculate and compare the value added of different business entities, a standard for the preparation and presentation of VAS ought to be published. In the South African context the need of a precise measurement of each business entity's contribution to the growth of the national economy is relevant, and this need should also be addressed.Value added, Gross Domestic Product, South Africa, financial statements