Die effek van die regulering van maksimum werkure op werknemers se grondwetlike reg op gelykheid

The paper examines the effect of the provisons regulating maximum working hours, with reference to the principle of equality entrenched in section 9 of the Constitution of the Republic of South Africa, 1996. Section 9(1) read with section 10(1) of the Basic Conditions of Employment Act 75/1997 has the effect that, subject to certain exceptions, employees are not allowed to work for the same employer for more than 55 hours per week. This does not prevent employees from working longer hours in total for different employers, an option that entails clear disadvantages. As a result of the adverse effect of past discrimination, black people, women and people on low socio-economic levels are disproportionately more unfavourably positioned in respect of levels of income, occupational status, financial ability and, consequentially, opportunities for promotion and improvement. This disadvantage often creates a need to work longer hours, specifically for the same employer. An application of the test developed in Harksen v Lane NO leads to a conclusion that the provisions referred to constitute unfair discrimination in terms of section 9 of the Constitution. The provisions also fail the proportionality test of section 36 of the Constitution

Spectral and stratigraphic mapping of hydrated sulfate and phyllosilicate-bearing deposits in northern Sinus Meridiani, Mars

We present detailed stratigraphic and spectral analyses that focus on a region in northern Sinus Meridiani located between 1°N to 5°N latitude and 3°W to 1°E longitude. Several stratigraphically distinct units are defined and mapped using morphologic expression, spectral properties, and superposition relationships. Previously unreported exposures of hydrated sulfates and Fe/Mg smectites are identified using MRO CRISM and MEX OMEGA near‐infrared (1.0 to 2.5 µm) spectral reflectance observations. Layered deposits with monohydrated and polyhydrated sulfate spectral signatures that occur in association with a northeast‐southwest trending valley are reexamined using highresolution CRISM, HiRISE, and CTX images. Layers that are spectrally dominated by monohydrated and polyhydrated sulfates are intercalated. The observed compositional layering implies that multiple wetting events, brine recharge, or fluctuations in evaporation rate occurred. We infer that these hydrated sulfate‐bearing layers were unconformably deposited following the extensive erosion of preexisting layered sedimentary rocks and may postdate the formation of the sulfate‐ and hematite‐bearing unit analyzed by the MER Opportunity rover. Therefore, at least two episodes of deposition separated by an unconformity occurred. Fe/Mg phyllosilicates are detected in units that predate the sulfateand hematite‐bearing unit. The presence of Fe/Mg smectite in older units indicates that the relatively low pH formation conditions inferred for the younger sulfate‐ and hematitebearing unit are not representative of the aqueous geochemical environment that prevailed during the formation and alteration of earlier materials. Sedimentary deposits indicative of a complex aqueous history that evolved over time are preserved in Sinus Meridiani, Mars

The role of educational strategies to reverse the inverse performance spiral in academically-isolated rural hospitals

The importance of continuous professional development for health care workers is widely acknowledged, but the identification of optimal implementation strategies remains a challenge, particularly in academically isolated rural areas. We report the results of a qualitative study that evaluated the effect of an educational intervention aimed at rural doctors in the Western Cape Province, South Africa. We also present a conceptual framework for developing best practice educational strategies to reverse the inverse performance spiral in academically isolated rural hospitals. Doctors felt that participation in relevant learning activities improved their competence, increased the levels of job satisfaction they experienced, increased their willingness to stay in a rural environment, and impacted positively on the quality of services provided. However, the success of educational strategies is heavily dependant on the local environment (context), as well as the practical applicability and clinical relevance of the activities (process). Successful educational strategies may help to reverse the inverse performance spiral previously described in academically isolated rural hospitals, however, this requires effective local leadership that creates a positive learning environment and supports clinically relevant learning activities. The study findings also indicate the need for health care providers and institutions of higher education to join forces to improve the quality of rural health care. South African Family Practice Vol. 49 (7) 2007: pp. 1

Global mortality from outdoor fine particle pollution generated by fossil fuel combustion: Results from GEOS-Chem

The burning of fossil fuels – especially coal, petrol, and diesel – is a major source of airborne fine particulate matter (PM2.5), and a key contributor to the global burden of mortality and disease. Previous risk assessments have examined the health response to total PM2.5, not just PM2.5 from fossil fuel combustion, and have used a concentration-response function with limited support from the literature and data at both high and low concentrations. This assessment examines mortality associated with PM2.5 from only fossil fuel combustion, making use of a recent meta-analysis of newer studies with a wider range of exposure. We also estimated mortality due to lower respiratory infections (LRI) among children under the age of five in the Americas and Europe, regions for which we have reliable data on the relative risk of this health outcome from PM2.5 exposure. We used the chemical transport model GEOS-Chem to estimate global exposure levels to fossil-fuel related PM2.5 in 2012. Relative risks of mortality were modeled using functions that link long-term exposure to PM2.5 and mortality, incorporating nonlinearity in the concentration response. We estimate a global total of 10.2 (95% CI: -47.1 to 17.0) million premature deaths annually attributable to the fossil-fuel component of PM2.5. The greatest mortality impact is estimated over regions with substantial fossil fuel related PM2.5, notably China (3.9 million), India (2.5 million) and parts of eastern US, Europe and Southeast Asia. The estimate for China predates substantial decline in fossil fuel emissions and decreases to 2.4 million premature deaths due to 43.7% reduction in fossil fuel PM2.5 from 2012 to 2018 bringing the global total to 8.7 (95% CI: -1.8 to 14.0) million premature deaths. We also estimated excess annual deaths due to LRI in children (0-4 years old) of 876 in North America, 747 in South America, and 605 in Europe. This study demonstrates that the fossil fuel component of PM2.5 contributes a large mortality burden. The steeper concentration-response function slope at lower concentrations leads to larger estimates than previously found in Europe and North America, and the slower drop-off in slope at higher concentrations results in larger estimates in Asia. Fossil fuel combustion can be more readily controlled than other sources and precursors of PM2.5 such as dust or wildfire smoke, so this is a clear message to policymakers and stakeholders to further incentivize a shift to clean sources of energy

Exact Baryon, Strangeness and Charge Conservation in Hadronic Gas Models

Relativistic heavy ion collisions are studied assuming that particles can be described by a hadron gas in thermal and chemical equilibrium. The exact conservation of baryon number, strangeness and charge are explicitly taken into account. For heavy ions the effect arising from the neutron surplus becomes important and leads to a substantial increase in e.g. the $\pi^-/\pi^+$ ratio. A method is developed which is very well suited for the study of small systems.Comment: 5 pages, 5 Postscript figure

Characterization of envelope function of transmitted viruses circulating in Mbeya, Tanzania, and its impact on disease progression

An understanding of the biological characteristics of transmitted viruses provides important insights into HIV pathogenesis and informs vaccine development. The aim of the study was to characterize env function of transmitted viruses and its role in disease progression

Laboratory investigations in lipidology

Advances in the causes of disorders of lipid metabolism, and effective intervention in atherosclerosis with medication, have increased the reliance on laboratory investigation in clinical practice. The conventional lipid profile, comprising fasting triglyceride, total cholesterol, high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol, suffices for screening persons at risk of atherosclerosis. Additionally, lipoprotein (a) measurement enhances risk assessment and could explain atherosclerosis with a desirable lipid profile. Certain rare disorders in sterol and fatty acid metabolism do not alter the conventional lipid profile. Non-fasting samples are gaining popularity, as the triglycerides, although mildly increased, signify atherogenic lipoprotein remnant accumulation. Apoprotein A1 (apo A1) and apo B concentrations parallel HDL cholesterol and LDL cholesterol, respectively, and are of value in disorders of these lipoproteins. In severe dyslipoproteinaemia, special investigations establish the cause of the disease and may allow selection of better treatment. In such cases, not only apoprotein concentrations, but also enzyme or cell function, as well as genetic investigations, are relevant. The most important genetic disorders to recognise are familial hypercholesterolaemia, dysbetalipoproteinaemia and chylomicronaemia. Expertise in lipidology is limited in South Africa, but specialist centres can provide clinical and laboratory support to ensure best management of severe disorders

Recombination dynamics of a human Y-chromosomal palindrome:rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions

The male-specific region of the human Y chromosome (MSY) includes eight large inverted repeats (palindromes) in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs) within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4) events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased), and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages

A Heuristic Image Search Algorithm for Active Shape Model Segmentation of the Caudate Nucleus and Hippocampus in Brain MR Images of Children with FASD

Magnetic Resonance Imaging provides a non-invasive means to study the neural correlates of Fetal Alcohol Spectrum Disorder (FASD) - the most common form of preventable mental retardation worldwide. One approach aims to detect brain abnormalities through an assessment of volume and shape of two sub-cortical structures, the caudate nucleus and hippocampus. We present a method for automatically segmenting these structures from high-resolution MR images captured as part of an ongoing study into the neural correlates of FASD. Our method incorporates an Active Shape Model, which is used to learn shape variation from manually segmented training data. A modified discrete Geometrically Deformable Model is used to generate point correspondence between training models. An ASM is then created from the landmark points. Experiments were conducted on the image search phase of ASM segmentation, in order to find the technique best suited to segmentation of the hippocampus and caudate nucleus. Various popular image search techniques were tested, including an edge detection method and a method based on grey profile Mahalanobis distance measurement. A novel heuristic image search method was also developed and tested. This heuristic method improves image segmentation by taking advantage of characteristics specific to the target data, such as a relatively homogeneous tissue colour in target structures. Results show that ASMs that use the heuristic image search technique produce the most accurate segmentations. An ASM constructed using this technique will enable researchers to quickly, reliably, and automatically segment test data for use in the FASD study