Diagnosis and Treatment of Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA) is the most frequent hyperglycaemic acute diabetic complication. Furthermore it carries a significant risk of death, which can be prevented by early and effective management. All physicians, irrespective of the discipline they are working in and whether in primary, secondary or tertiary care institutions, should be able to recognise DKA early and initiate management immediately. South African Family Practice Vol. 50 (1) 2008: pp. 35-3

Constructing a Sophistication Index as a Method of Market Segmentation of Commercial Farming Businesses in South Africa

This study investigates the process of index construction as a means of measuring a hypothetical construct that can typically not be measured by a single question or item and applying it as a method of market segmentation. The availability of incidental secondary data provided a relevant quantitative basis to illustrate this process by constructing a commercial farming sophistication index for South Africa. It was evident that this approach offers an appropriate and useful means of segmenting a market. Several factors contribute to the appeal of this approach. Among others, it addresses important priorities in the area of future segmentation research. By offering classification rules based on characteristics that can easily be observed or elicited through asking a few key questions, new or potential buyers can be grouped by buying behaviour segment. Furthermore, the multi-step process that was employed provides a systematic and structured multivariate approach to segmentation. It also facilitates replication of the process when conducting future studies. Lastly, the outcome of this type of segmentation method offers researchers and marketing practitioners a procedure, in the form of an equation, to calculate index scores and provide rules to segment the market based on predefined intervals. Hence, the challenge to replicate segment formation across independent future studies is addressed.Keywords: Agribusiness, Commercial Farming, Index Construction, Segmentation, Sophisticatio

Magnetoplasmon excitations in an array of periodically modulated quantum wires

Motivated by the recent experiment of Hochgraefe et al., we have investigated the magnetoplasmon excitations in a periodic array of quantum wires with a periodic modulation along the wire direction. The equilibrium and dynamic properties of the system are treated self-consistently within the Thomas-Fermi-Dirac-von Weizsaecker approximation. A calculation of the dynamical response of the system to a far-infrared radiation field reveals a resonant anticrossing between the Kohn mode and a finite-wavevector longitudinal excitation which is induced by the density modulation along the wires. Our theoretical calculations are found to be in excellent agreement with experiment.Comment: 9 pages, 8 figure

Calibration artefacts in radio interferometry. I. Ghost sources in WSRT data

This work investigates a particular class of artefacts, or ghost sources, in radio interferometric images. Earlier observations with (and simulations of) the Westerbork Synthesis Radio Telescope (WSRT) suggested that these were due to calibration with incomplete sky models. A theoretical framework is derived that validates this suggestion, and provides predictions of ghost formation in a two-source scenario. The predictions are found to accurately match the result of simulations, and qualitatively reproduce the ghosts previously seen in observational data. The theory also provides explanations for many previously puzzling features of these artefacts (regular geometry, PSF-like sidelobes, seeming independence on model flux), and shows that the observed phenomenon of flux suppression affecting unmodelled sources is due to the same mechanism. We demonstrate that this ghost formation mechanism is a fundamental feature of calibration, and exhibits a particularly strong and localized signature due to array redundancy. To some extent this mechanism will affect all observations (including those with non-redundant arrays), though in most cases the ghosts remain hidden below the noise or masked by other instrumental artefacts. The implications of such errors on future deep observations are discussed.Comment: 19 pages, 15 figures, submitted to MNRA

Optical and microphysical characterization of aerosol layers over South Africa by means of multi-wavelength depolarization and Raman lidar measurements

© 2016 The Author(s). Published by Copernicus Publications on behalf of the European Geosciences Union. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence ( https://creativecommons.org/licenses/by/3.0/ ), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.Optical and microphysical properties of different aerosol types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to aerosol properties over South Africa, since limited long-term data of this type is available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the aerosol optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical aerosol properties, i.e. effective radius and single scattering albedo were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric layers of biomass burning and urban/industrial aerosols. Our results reveal a wide range of optical and microphysical parameters for biomass burning aerosols. This indicates probable mixing of biomass burning aerosols with desert dust particles, as well as the possible continuous influence of urban/industrial aerosol load in the region. The lidar ratio at 355 nm, the lidar ratio at 532 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr; 41 ± 13 sr; 0.9 ± 0.4 % and 2.3 ± 0.5, respectively for urban / industrial aerosols, while these values were 92 ± 10 sr; 75 ± 14; 3.2 ± 1.3 % and 1.7 ± 0.3 respectively for biomass burning aerosols layers. Biomass burning particles are larger and slightly less absorbing compared to urban / industrial aerosols. The particle effective radius were found to be 0.10 ± 0.03 μm, 0.17 ± 0.04 μm and 0.13 ± 0.03 μm for urban/industrial, biomass burning, and mixed aerosols, respectively, while the single scattering albedo at 532 nm were 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532 nm), respectively for these three types of aerosols. Our results were within the same range of previously reported values.Peer reviewedFinal Published versio

Human cytomegalovirus immunoglobulin G response and pulmonary tuberculosis in adolescents: a case-control study

Background Emerging evidence suggests a link between infection with herpes viruses, particularly human cytomegalovirus (HCMV) and Epstein Barr Virus (EBV), and progression to tuberculosis (TB) disease. Methods An unmatched case-control study was conducted amongst adolescents aged 10-19 years enrolled in an observational study (Teen TB), between November 2020 and November 2021, in Cape Town, South Africa. Fifty individuals with pulmonary TB and 51 healthy TB-exposed individuals without TB were included. Demographics and clinical data were obtained, and serum samples collected at enrolment were tested for HCMV IgG and EBV Nuclear Antigen (EBNA) IgG using two automated enzyme immunoassays. Odds ratios (ORs) were estimated using unconditional logistic regression. Results The median age of 101 participants was 15 years (interquartile range [IQR] 13 to 17); 55 (54%) were female. All participants were HCMV IgG seropositive and 95% were EBNA IgG seropositive. Individuals with TB had higher HCMV IgG titres than healthy controls (p=0.04). Individuals with upper tertile HCMV IgG titres had a 3.7 times greater odds of pulmonary TB compared to those with IgG titres in the lower tertile (95%CI: 1.05–12.84; p=0.04). There was a trend for increasing odds of pulmonary TB with increasing titres of HCMV IgG (p=0.04). In contrast, there was no association between TB and higher EBNA IgG values. Conclusions There is a high prevalence of sensitisation to HCMV and EBV amongst adolescents in this high-TB burden setting. Higher HCMV IgG titres were associated with pulmonary TB in adolescents

Chlorido{N-[2-(diphenylphosphanyl)- benzyl]-1-(pyridin-2-yl)methanamine-kP} gold(I)

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Theoretical Modeling of the Thermal State of Accreting White Dwarfs Undergoing Classical Novae

White dwarfs experience a thermal renaissance when they receive mass from a stellar companion in a binary. For accretion rates < 10^-8 Msun/yr, the freshly accumulated hydrogen/helium envelope ignites in a thermally unstable manner that results in a classical novae (CN) outburst and ejection of material. We have undertaken a theoretical study of the impact of the accumulating envelope on the thermal state of the underlying white dwarf (WD). This has allowed us to find the equilibrium WD core temperatures (T_c), the classical nova ignition masses (M_ign) and the thermal luminosities for WDs accreting at rates of 10^-11 - 10^-8 Msun/yr. These accretion rates are most appropriate to WDs in cataclysmic variables (CVs) of P_orb <~ 7 hr, many of which accrete sporadically as dwarf novae. We have included ^3He in the accreted material at levels appropriate for CVs and find that it significantly modifies the CN ignition mass. We compare our results with several others from the CN literature and find that the inclusion of ^3He leads to lower M_ign for >~ 10^-10 Msun/yr, and that for below this the particular author's assumption concerning T_c, which we calculate consistently, is a determining factor. Initial comparisons of our CN ignition masses with measured ejected masses find reasonable agreement and point to ejection of material comparable to that accreted.Comment: 14 pages, 11 figures; uses emulateapj; accepted by the Astrophysical Journal; revised for clarity, added short discussion of diffusio

Stream-field interactions in the magnetic accretor AO Piscium

UV spectra of the magnetic accretor AO Psc show absorption features for half the binary orbit. The absorption is unlike the wind-formed features often seen in similar stars. Instead, we attribute it to a fraction of the stream that overflows the impact with the accretion disk. Rapid velocity variations can be explained by changes in the trajectory of the stream depending on the orientation of the white-dwarf's magnetic field. Hence we are directly observing the interaction of an accretion stream with a rotating field. We compare this behavior to that seen in other intermediate polars and in SW Sex stars.Comment: Accepted for ApJ; 6 page