264 research outputs found
A patient-centric Six-Sigma decision support system framework for continuous quality improvement in clinics
CITATION: Hlongwane, S., Ngongoni, C. & Grobbelaar, S. S. 2019. A patient-centric Six-Sigma decision support system framework for continuous quality improvement in clinics. South African Journal of Industrial Engineering, 30(3):224-237, doi:10.7166/30-3-2241.The original publication is available at http://sajie.journals.ac.zaENGLISH ABSTRACT: Primary health care facilities are widely regarded as the backbone of the South African healthcare system. For this reason, formalised standards such as the ‘ideal clinic’ and ‘national core standards’ dictate expected service levels for clinics. Although this is a big step towards the improvement of service delivery at the facilities, the level of uptake of and adherence to these standards is concerning. Service quality plays a huge role in the level of patient satisfaction, and emphasis is placed on the features of quality that are of importance to the patient. To this end, the focus on the patient is an important dimension in healthcare quality management in order to improve the service quality in healthcare facilities. This article provides an overview of quality and how it is managed in the context of clinics in South Africa. It outlines the gaps, aligned with how well quality is managed, from a patient perspective. The paper proposes a decision support framework aimed at continuous improvement of quality in clinics. The tool was developed using the Six Sigma methodology, complemented by service quality assessment instruments. The structure of the tool provides an integrated systematic approach that can assist the healthcare decision-maker in tracking the continuous improvement of processes and activities in clinics. The tool also takes the first step towards digitising a typical paper-based system.AFRIKAANS OPSOMMING: Primêre gesondheidsorgfasiliteite word wyd beskou as die ruggraat van die Suid-Afrikaanse gesondheidsorgstelsel. Om hierdie rede word formele standaarde deur die ‘ideale kliniek’ en ‘Nasionale kernstandaarde’ bepaal. Alhoewel dit ʼn groot stap is vir die verbetering van dienslewering by die fasiliteite, is die vlak van opname en nakoming van hierdie standaarde kommerwekkend. Diensgehalte speel ʼn groot rol in die vlak van pasiëntbevrediging, en klem word geplaas op die eienskappe van kwaliteit wat van belang is vir die pasiënt. Vir hierdie doel is die fokus op die pasiënt ʼn belangrike dimensie in gesondheidsorgkwaliteitsbestuur ten einde die diensgehalte in gesondheidsorgfasiliteite te verbeter. Hierdie artikel bied ʼn oorsig oor kwaliteit en hoe dit in die konteks van klinieke in Suid-Afrika bestuur word. Dit beskryf die gapings van hoe goed kwaliteit bestuur word, uit ʼn pasiëntperspektief. Die artikel stel ʼn besluitsteunraamwerk voor wat op deurlopende verbetering van gehalte in klinieke gemik is. Die instrument is ontwikkel met behulp van die Ses-Sigma metodologie, aangevul deur dienskwaliteit assesseringsinstrumente. Die struktuur van die instrument bied ʼn geïntegreerde sistematiese benadering wat die gesondheidsorgbesluitnemer kan help om die deurlopende verbetering van prosesse en aktiwiteite in klinieke te monitor. Die instrument neem ook die eerste stap in die rigting van digitalisering van ʼn tipiese papiergebaseerde stelsel.http://sajie.journals.ac.za/pub/article/view/2241Publisher's versio
Water and CSP - linking CSP water demand models and national hydrology data to sustainably manage CSP development and water resources in arid regions
CITATION: Duvenhage, D. Frank et al. 2020. Water and CSP - linking CSP water demand models and national hydrology data to sustainably manage CSP development and water resources in arid regions. Sustainability, 12(8): 3373, doi:10.3390/su12083373.The original publication is available at: https://www.mdpi.comENGLISH ABSTRACT: A systematic approach to evaluate Concentrating Solar Power (CSP) plant fleet deployment
and sustainable water resource use in arid regions is presented. An overview is given of previous
work carried out. Once CSP development scenarios, suitable areas for development, and the water
demand from CSP operations were evaluated, appropriate spatiotemporal CSP performance models
were developed. The resulting consumptive patterns and the impact of variable resource availability
on CSP plant operation are analysed. This evaluation considered the whole of South Africa, with focus
on the areas identified as suitable for CSP, in order to study the impact on local water resources. It was
found that the hydrological limitations imposed by variable water resources on CSP development
are severe. The national annual theoretical net generation potential of wet-cooled Parabolic Trough
decreased from 11,277 to 120 TWh, and that of wet-cooled Central Receiver decreased from 12,003 to
170 TWh. Dry cooled versions also experience severe limitations, but to a lesser extent—the national
annual theoretical net generation potential of Parabolic Trough decreased from 11,038 to 512 TWh,
and that of Central Receiver decreased from 11,824 to 566 TWh. Accordingly, policy guidelines are
suggested for sustainable CSP development and water resource management within the context of
current South African water use regulation.Publisher's versio
PAPER-64 Constraints On Reionization II: The Temperature Of The z=8.4 Intergalactic Medium
We present constraints on both the kinetic temperature of the intergalactic
medium (IGM) at z=8.4, and on models for heating the IGM at high-redshift with
X-ray emission from the first collapsed objects. These constraints are derived
using a semi-analytic method to explore the new measurements of the 21 cm power
spectrum from the Donald C. Backer Precision Array for Probing the Epoch of
Reionization (PAPER), which were presented in a companion paper, Ali et al.
(2015). Twenty-one cm power spectra with amplitudes of hundreds of mK^2 can be
generically produced if the kinetic temperature of the IGM is significantly
below the temperature of the Cosmic Microwave Background (CMB); as such, the
new results from PAPER place lower limits on the IGM temperature at z=8.4.
Allowing for the unknown ionization state of the IGM, our measurements find the
IGM temperature to be above ~5 K for neutral fractions between 10% and 85%,
above ~7 K for neutral fractions between 15% and 80%, or above ~10 K for
neutral fractions between 30% and 70%. We also calculate the heating of the IGM
that would be provided by the observed high redshift galaxy population, and
find that for most models, these galaxies are sufficient to bring the IGM
temperature above our lower limits. However, there are significant ranges of
parameter space that could produce a signal ruled out by the PAPER
measurements; models with a steep drop-off in the star formation rate density
at high redshifts or with relatively low values for the X-ray to star formation
rate efficiency of high redshift galaxies are generally disfavored. The PAPER
measurements are consistent with (but do not constrain) a hydrogen spin
temperature above the CMB temperature, a situation which we find to be
generally predicted if galaxies fainter than the current detection limits of
optical/NIR surveys are included in calculations of X-ray heating.Comment: companion paper to Ali et al. (2015), ApJ 809, 61; matches version
accepted to ApJ; 11 pages, 7 figure
Incidence of Tuberculosis amongst HIV positive individuals initiating antiretroviral treatment at higher CD4 counts in the HPTN 071 (PopART) trial in South Africa.
INTRODUCTION: Antiretroviral treatment (ART) guidelines recommend lifelong ART for all HIV positive individuals. This study evaluated TB incidence on ART in a cohort of HIV positive individuals starting ART regardless of CD4 count in a programmatic setting at three clinics included in the HPTN 071 (PopART) trial in South Africa. METHODS: A retrospective cohort analysis of HIV-positive individuals aged ≥18 years starting ART, between January 2014 and November 2015, was conducted. Follow up was continued until 30 May 2016 or censored on the date of i) incident TB ii) loss to follow up from HIV care or death or iii) elective transfer out; whichever occurred first. RESULTS: The study included 2423 individuals. Median baseline CD4 count was 328 cells/µL (IQR 195-468), TB incidence rate was 4.41/100 PY (95% CI 3.62-5.39). The adjusted hazard ratio of incident TB was 0.27 (95% CI 0.12 - 0.62) when comparing individuals with baseline CD4 > 500cells/µL and ≤ 500cells/µL. Amongst individuals with baseline CD4 count > 500cells/µL there were no incident TB cases in the first three months of follow up. Adjusted hazard of incident TB was also higher amongst men (aHR 2.16; 95% CI: 1.41 - 3.30). CONCLUSION: TB incidence after ART initiation was significantly lower amongst individuals starting ART at CD4 counts above 500cells/µL. Scale up of ART, regardless of CD4 count, has the potential to significantly reduce TB incidence amongst HIV-positive individuals. However, this needs to be combined with strengthening of other TB prevention strategies that target both HIV positive and HIV negative individuals
Hydrogen Epoch of Reionization Array (HERA)
The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to
measure 21 cm emission from the primordial intergalactic medium (IGM)
throughout cosmic reionization (), and to explore earlier epochs of our
Cosmic Dawn (). During these epochs, early stars and black holes
heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is
designed to characterize the evolution of the 21 cm power spectrum to constrain
the timing and morphology of reionization, the properties of the first
galaxies, the evolution of large-scale structure, and the early sources of
heating. The full HERA instrument will be a 350-element interferometer in South
Africa consisting of 14-m parabolic dishes observing from 50 to 250 MHz.
Currently, 19 dishes have been deployed on site and the next 18 are under
construction. HERA has been designated as an SKA Precursor instrument.
In this paper, we summarize HERA's scientific context and provide forecasts
for its key science results. After reviewing the current state of the art in
foreground mitigation, we use the delay-spectrum technique to motivate
high-level performance requirements for the HERA instrument. Next, we present
the HERA instrument design, along with the subsystem specifications that ensure
that HERA meets its performance requirements. Finally, we summarize the
schedule and status of the project. We conclude by suggesting that, given the
realities of foreground contamination, current-generation 21 cm instruments are
approaching their sensitivity limits. HERA is designed to bring both the
sensitivity and the precision to deliver its primary science on the basis of
proven foreground filtering techniques, while developing new subtraction
techniques to unlock new capabilities. The result will be a major step toward
realizing the widely recognized scientific potential of 21 cm cosmology.Comment: 26 pages, 24 figures, 2 table
PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM AT z = 8.4
In this paper, we report new limits on 21 cm emission from cosmic reionization based on a 135 day observing campaign with a 64-element deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization in South Africa. This work extends the work presented in Parsons et al. with more collecting area, a longer observing period, improved redundancy-based calibration, improved fringe-rate filtering, and updated power-spectral analysis using optimal quadratic estimators. The result is a new 2σ upper limit on Δ[superscript 2](k) of (22.4 mK)[superscript 2] in the range 0.15 < k < 0.5h Mpc[superscript -1] at z = 8.4. This represents a three-fold improvement over the previous best upper limit. As we discuss in more depth in a forthcoming paper, this upper limit supports and extends previous evidence against extremely cold reionization scenarios. We conclude with a discussion of implications for future 21 cm reionization experiments, including the newly funded Hydrogen Epoch of Reionization Array
Renal dysfunction by baseline CD4 cell count in a cohort of adults starting antiretroviral treatment regardless of CD4 count in the HIV Prevention Trials Network 071 [HPTN 071; Population Effect of Antiretroviral Therapy to Reduce HIV Transmission (PopART)] study in South Africa.
OBJECTIVES: Renal dysfunction is a significant cause of morbidity and mortality among HIV-positive individuals. This study evaluated renal dysfunction in a cohort of adults who started antiretroviral treatment (ART) regardless of CD4 count at three Department of Health (DOH) clinics included in the HIV Prevention Trials Network 071 (HPTN 071) Population Effect of Antiretroviral Therapy to Reduce HIV Transmission (PopART) trial. METHODS: A retrospective cohort analysis of routine data for HIV-positive individuals starting ART between January 2014 and November 2015 was completed. Incident renal dysfunction was defined as an estimated glomerular filtration rate (eEGFR)  500 cells/μL [adjusted odds ratio (aOR) 0.29; 95% confidence interval (CI) 0.11-0.80], 351-500 cells/μL (aOR 0.22; 95% CI 0.08-0.59) and 201-350 (aOR 0.48; 95% CI: 0.24-0.97) compared with baseline CD4 counts  200 cells/μL. Strategies that use baseline characteristics, such as age, to identify individuals at high risk of renal dysfunction on ART for enhanced eGFR monitoring may be effective and should be the subject of future research
Adjusted Light and Dark Cycles Can Optimize Photosynthetic Efficiency in Algae Growing in Photobioreactors
Biofuels from algae are highly interesting as renewable energy sources to replace, at least partially, fossil fuels, but great research efforts are still needed to optimize growth parameters to develop competitive large-scale cultivation systems. One factor with a seminal influence on productivity is light availability. Light energy fully supports algal growth, but it leads to oxidative stress if illumination is in excess. In this work, the influence of light intensity on the growth and lipid productivity of Nannochloropsis salina was investigated in a flat-bed photobioreactor designed to minimize cells self-shading. The influence of various light intensities was studied with both continuous illumination and alternation of light and dark cycles at various frequencies, which mimic illumination variations in a photobioreactor due to mixing. Results show that Nannochloropsis can efficiently exploit even very intense light, provided that dark cycles occur to allow for re-oxidation of the electron transporters of the photosynthetic apparatus. If alternation of light and dark is not optimal, algae undergo radiation damage and photosynthetic productivity is greatly reduced. Our results demonstrate that, in a photobioreactor for the cultivation of algae, optimizing mixing is essential in order to ensure that the algae exploit light energy efficiently
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