50 research outputs found
Testing the orphanhood method against benchmark mortality rates in South Africa since 1996
Includes abstract.Includes bibliographical references (leaves 71-73).This study utilises the 1996 and 2001 Censuses, and the 2007 Community Survey to test the orphanhood method mortality estimates against consensus estimates of mortality produced using other methods. In all the two censuses and the survey there were questions on the survival status of the respondent’s biological parents. The orphanhood method is widely used in developing countries where the vital registration is incomplete. In countries where the data on survival of parents has been compared with other mortality estimates, it has been observed that the orphanhood method estimates are biased by adoption effect, selection effect and age exaggeration. In the late 1980s and early 1990s, the advent of HIV/AIDS has also biased estimates obtained from the orphanhood method. Non-independence of the mortality of children and their mothers, relationships between HIV infection and fertility, and changes in age-specific mortality result in biases which affect the accuracy of the method. These biases have been observed to have a net effect of underestimating mortality especially female mortality. An adjusted method has been proposed which reduces error, when working with data taken from populations with a significant HIV prevalence. This adjustment can be applied, but further research to identify revised adjustments would further improve the accuracy of the method. The current research applies four variants of the orphanhood method, the regression variant, UN Manual’s two-survey variant, Timaeus’s synthetic cohort variant and the one allowing for HIV/AIDS proposed by Timaeus and Nunn
Analysis and integration of regional scale temperature datasets into a seasonal crop monitoring system.
Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.Populations in excess of 20 million people in southern Africa annually face food insecurity.
This number increases appreciably when detrimental seasonal climate conditions lead to
widespread reductions in crop harvests. This situation has led to the development of regionalscale
crop monitoring systems that incorporate crop-specific water balance (CSWB) models for
early detection and warning of impending weather-related crop production shortfalls. Early
warning of anticipated reductions in crop harvests facilitates early action in responding to
potential crises. One such system, used by the Famine Early Warning Systems Network (FEWS
NET) in southern Africa for crop monitoring, calculates the water requirements satisfaction
index (WRSI) using a CSWB model. Operationally, CSWB models for calculating WRSI have
used a static length of growing period (LGP) to bracket the period over which rainfall and
evapotranspiration variations can affect crop yields. In the long term, concerns have been raised
by some studies on the impact of rising air temperatures on crop production. There is therefore
a need to incorporate the impacts of air temperature on crops directly into food security
monitoring systems, in order to improve the accuracy of these monitoring systems in identifying
and locating weather-related crop production shortfalls. This study sought to assess the potential
improvements that can be introduced to the crop monitoring system in general and the WRSI
in particular, by incorporating air temperature data into the CSWB model. To address this
objective, daily maximum and minimum air temperature grids derived from a general
circulation model reanalysis were used to generate thermal time estimates, expressed as
growing degree day (GDD) grids for a maize crop. The GDDs were used to estimate the LGP
of maize for each pixel of each summer season (which typically runs between around October
and March) from 1982/1983 to 2016/2017 in southern Africa. The variable, temperature-driven
LGP estimates compared favourably with LGP values obtained from literature for a few sample
locations. The variable LGP was used to calculate the WRSI for 35 seasons, and the resultant
WRSI showed improved correlation with historical yield estimates compared to the static-LGP
WRSI, particularly after the farming practice of planting on multiple dates was taken into
consideration. Various expressions of WRSI were considered in the analysis, including WRSI
calculated assuming planting at the onset of rains, WRSI aggregated from varying number of
separate planting dates, including three and six planting dates as test examples, and WRSI
calculated using a modified soil water holding capacity to better capture local soil management
practices. Historical maize yields for sub-national administrative units from seven southern
African countries were correlated with the various WRSI expressions. Gridded GDD data that
reflect the accumulated severity of extreme warm temperatures experienced during the crop
growth period, referred to as extreme growing degree days, or eGDD, were also noted to have
significant correlations with historical maize yields in several southern African countries. A
number of variants of the eGDDs were tested, including eGDDs accumulated throughout the
crop’s growth period, eGDDs that only occurred simultaneously with periods of crop water
deficit, eGDDs that occurred during the crop flowering stage, and eGDDs scaled by the severity
of crop water deficit. In several areas, the various eGDD expressions indicated higher
correlations with yield than any of the WRSI variants indicated. The eGDD parameter showed
strong correlations with WRSI, suggesting that the accumulated high temperatures were a
reflection of the influence of low rainfall and low soil moisture during episodes of high
temperature. More work is required to calibrate and refine the temperature-based monitoring
parameters that were developed in this study, at local, sub-national scales. In particular,
assumptions of the linearity of maize yield response for the various parameters should be tested.
Potential improvements of the combined eGDD-water deficit parameter through the
incorporation of prediction coefficients and constants should also be tested. A secondary aim
of the study was to explore how readily available temperature-related datasets can be utilized
to derive air-temperature metrics. To this end, satellite-derived thermal infrared (TIR)
brightness temperature data were analysed, and a method was developed for identifying cloud
cover, while simultaneously estimating cloud-free diurnal brightness temperature curves, using
a single TIR satellite channel. The diurnal brightness temperature curves were developed using
a sinusoidal and exponential model for daytime and nighttime respectively, utilizing
modifications that enabled the curves to be estimated from two known temperatures at any two
given times with cloud-free brightness temperature scenes. Comparison of the cloud mask
developed in this study with an existing operational cloud mask based on a methodology
developed by the EUMETSAT Satellite Applications Facility for Nowcasting gave an accuracy
of 85.4%, when the operational method was considered as truth in a confusion matrix analysis.
Situations were identified in which the different cloud detection methods showed superior
performance, and could therefore complement each other. A statistical method was also
developed for calibrating the cloud-free brightness temperatures to station-observed 2-m air
temperatures using relationships between the means and diurnal temperature ranges of the two
datasets. This enabled the identification of periods of occurrence of extreme warm air
temperatures with a coefficient of determination of 0.91, and demonstrated the potential for the
usage of TIR data for generating estimates of useful air temperature metrics. The efficiency of
the algorithms that were used for simultaneous cloud masking and generation of cloud-free
brightness temperature should be improved, in order to enable the methodology to be scaled up
to a regional or global gridded level of analysis. Further work for improving operational gridded
air temperature datasets by combining station-observed temperature data, modelled data from
global circulation models, satellite-derived modelled cloud-free brightness temperature data
and cloud masks is recommended
Essays on social protection and human welfare in Southern Africa
The potential of social protection to ensure well-being and food security in Southern Africa is gaining renewed interest in the presence of unprecedented shocks such as the COVID-19 pandemic and the incessant climate-change induced disasters. This study investigates the impact of social protection on welfare in Southern Africa and is comprised of three papers. In the first paper, I analyzed whether the Foster Care Grant in South Africa has an impact on child health. Based on five waves of the National Income Dynamics Study, the findings indicate that the grant improves height-for-age z-score by 0.23 standard deviations for children who received the grant compared to their counterpart and by 0.14 standard deviations for children who received the grant twice compared to those that received it only once. However, there is no further marginal impact for girls who receive the grant twice when compared to those that receive it only once. In the second paper, I assessed the impact of social capital on food security in Zimbabwe based on Zimbabwe Vulnerability Assessment Committee data, finding that households with social capital are more food secure and are more likely to receive agricultural extension services. In the third paper, I assessed the impact of social protection and the Special COVID-19 Social Relief of Distress Grant on hunger in South Africa. Based on two waves of the National Income Dynamics Study - Coronavirus Rapid Mobile Survey, the findings indicate that receiving a government grant reduces the likelihood of going hungry and running out of money to buy food by 6 and 12 percentage points respectively, and receiving the special COVID-19 Social Relief of Distress Grant lowers chances of child hunger. Further, the findings indicate no heterogeneity on hunger between those that were screened or tested for COVID-19 and those who were not
Improving access to medicines through centralised dispensing in the public sector: a case study of the Chronic Dispensing Unit in the Western Cape Province, South Africa
Reconstruction of a fire regime using MODIS burned area data : Charara Safari Area, Zimbabwe
Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Current efforts to address Zimbabwe‘s decade long veld fire crisis has partly been hindered by a lack of financial resources and fire data. This study illustrates the potential of using the MODIS burned area product as an alternative cost- and time-effective method for reconstructing historical fire records in Zimbabwe. Two MODIS burned area products were evaluated, namely the MCD45A1 and WAMIS (Meraka Institute‘s MODIS burned area product). Both products yielded similar levels of accuracy despite the difference in algorithms. However, it is assumed that at certain thresholds, either in tree cover or fire intensity, WAMIS ceases to map fires as accurately as the MCD45A1. Ten years of fire data for Charara Safari Area (CSA) was extracted from the MCD45A1, and used as a basis to establish six parameters: fire incidence, extent, seasonality, fire size, frequency and fire return interval (FRI). It was observed that approximately 50% of CSA burned annually, with an average of 132 fires occurring every year. Although there was no overall increase or decrease in the extent of area burned over the 10 year study period, an increasing trend in fire incidence was noted. Through an assessment of effective fire size, it was established that more fires in CSA were gradually becoming smaller in size, while the extent of area burned remained fairly constant. Hence, the increase in fire incidences and lack of a corresponding increase in area burned. This study was also used to identify areas in the fire regime that may be a potential ecological risk to the miombo woodland in CSA. Three points of concern were revealed: firstly, a high prevalence of late season fires was observed in the northern bounds of CSA. Secondly, 64.2% of the total area burned in CSA burned between 6 and 10 times over the 10 year period, and lastly, 85% of the total area burned over the period 2001 and 2010 had a FRI of less than 2 years. The combination of late season fires, high fire frequency and short FRI in CSA is indicative of possible alterations in the state of the miombo woodlands, which may have negative socio-economic implications on CSA and its surrounding communities. This study has demonstrated that the MCD45A1 is a useful source of much needed fire information for Zimbabwe. Therefore, the possibility of integrating methods employed in this study into the current collection of fire data should be given due consideration.AFRIKAANSE OPSOMMING: Huidige pogings om Zimbabwe se dekade lank veldbrand krisis aan te spreek is gedeeltelik belemmer deur 'n gebrek aan finansiële hulpbronne en vuurdata. Hierdie studie illustreer die potensiaal van die gebruik van die MODIS verbrande area produk as 'n alternatiewe koste-en tyd-effektiewe metode vir die rekonstruksie van historiese vuurrekords in Zimbabwe. Twee MODIS verbrande area produkte is geëvalueer, naamlik die MCD45A1 en WAMIS (Meraka Instituut se MODIS verbrand area produk). Beide produkte het soortgelyke vlakke van akkuraatheid opgelewer ten spyte van die verskil in die algoritmes. Dit word egter aanvaar dat op sekere drempels, óf in die boom bedekking, of brandintensiteit, WAMIS brande minder akkuraat karteer as die MCD45A1 produk. Tien jaar van vuurdata vir Charara Safari Area (CSA) is uit die MCD45A1 data onttrek, en gebruik as 'n basis om ses parameters vas te stel: vuurvoorkoms, omvang, seisoenaliteit, vuurgrootte, frekwensie en tyd tussen die terugkeer van vuur na ‗n spesifieke plek (nl. FRI). Dit is waargeneem dat ongeveer 50% van die CSA jaarliks gebrand word, met 'n gemiddeld van 132 brande wat elke jaar voorkom. Daar was nie 'n algehele toename of afname in die omvang van die totale verbrande area oor die 10 jaar studietydperk nie. Maar 'n toenemende neiging in die vuurvoorkoms was wel opgemerk. Deur middel van 'n assessering van effektiewe vuurgrootte, is daar vasgestel dat meer kleiner brande in CSA voorkom, terwyl die omvang van die verbrand area redelik konstant gebly het. Dus was daar ‗n toename in die aantal vuurvoorvalle al was daar nie 'n ooreenstemmende toename in die totale verbrande oppervlakte was nie. Hierdie studie is ook gebruik om gebiede in die vuurregime te identifiseer wat 'n potensiële ekologiese risiko vir die miombobosveld in CSA inhou. Drie punte van kommer word geopenbaar: eerstens, 'n hoë voorkoms van laatseisoen brande is waargeneem in die noordelike grense van CSA. Tweedens, 64,2% van die totale verbrande oppervlakte in die CSA brand tussen 6 en 10 keer bine die 10-jaar periode. Laastens, 85% van die totale verbrande oppervlakte oor die tydperk 2001 tot 2010 het 'n FRI van minder as twee jaar. Die kombinasie van laatseisoen brande, hoë vuurfrekwensie en kort FRI in CSA is 'n aanduiding van moontlike veranderinge in die toestand van die miomboveld, wat negatiewe sosio-ekonomiese implikasies op die CSA en die omliggende gemeenskappe kan uitoefen. Hierdie studie het getoon dat die MCD45A1 'n nuttige bron van broodnodige vuur inligting vir Zimbabwe is. Daarom, moet die moontlikheid van die integrasie van die metodes wat gebruik word in hierdie studie in die huidige versameling van vuurdata behoorlike oorweging gegee word
a case of the child support grant in South Africa
Thesis(Doctoral) --KDI School:Ph.D in Public Policy,2014doctoralpublishedVengesai Magadzire
Analgesic efficacy of a novel topical formulation for tail docking in piglets : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Palmerston North, New Zealand
The following Figures were removed for copyright reasons:
Figures 2.1 (=Herskin et al., 2016 Fig 1), 2.2 (Kehlet et al., 2006 Fig 1), 2.3 (=Di Giminiani et al., 2016 Fig 3), 2.4 (=Theurer et al., 2013 Fig 1), 2.5 (=Prunier et al., 2005 Fig 1B & 3B), 2.6 (=Sutherland et al., 2008 Fig 1) & 2.7 (=Zhang & An, 2007 Fig 1).Tail docking of young piglets is a common management procedure which is carried out on pig farms to prevent tail biting behaviour. In New Zealand, pain relief is not required at the time of the procedure if piglets are less than 7 days old. However, tail docking results in behavioural and physiological pain and stress responses in piglets. A survey of pig husbandry practices was carried out before conducting the experimental procedure. The survey had 15 questions which focused on the occurrence of tail biting, of which only one respondent reported tail biting absence. Most questions were centred on tail biting risk factors coming from housing conformations, use of manipulable substances such as straw and feeding systems. Knowledge of farmers’ strategies concerning risk factors can enable stakeholders to advise farmers on the best ways to minimise tail biting. The objective of this research was to evaluate the analgesic efficacy of a novel topical formulation to reduce pain due to tail docking. This was examined in 108 piglets (9 litters of 12 piglets each), which were docked by a gas cautery iron at approximately 2-3 days of age. The study had 3 treatment groups: pain relief provided before docking, (‘Before’); pain relief provided after docking (‘After’); and the control group which had no pain relief (‘Control’). The 9 litters were randomly allocated, such that each treatment group had 3 litters. The behavioural response to docking was recorded during and after docking. The percentages and means for vocalisations and escape attempts before docking were recorded, and these were lowest in the ‘before’ group (P<.0001). Post docking, treatment had a highly significant effect on walking behaviour (P<0.0002). Piglets in the control group had the highest likelihood of walking after docking, followed by the after and before groups respectively. Lying in contact, which signifies social coherence, was more apparent in the before group, (P<0.0001) followed by the after group and was observed at the lowest frequency in the control group. Conversely, the lying in isolation behaviour was highest in the control group, (P<0.0002), followed by the after group and lastly the before group. Sitting and pain related behaviours had the highest occurrences in control piglets, followed by the after group and lastly the before group. Blood sampling was carried out to conduct inflammatory gene expression studies which suggest the level of pain. The results from the study were unbalanced, therefore inconclusive due to sampling challenges which resulted in limited raw data. Blood samples from piglets that had not received pain relief prior to docking were especially difficult to collect. The blood work sought to analyse which cytokines, pro-inflammatory and anti-inflammatory genes would be upregulated following pain due to tail docking. Pre-emptive application of the topical analgesic formulation resulted in fewer pain related behaviour displays but was the most labour-intensive treatment. Further work is required to develop more practical forms of on-farm pain relief during tail docking
Utilization of sorghum grain in high energy beef finish diets
A JASSA study on animal nutrition to achieve better quality beef in the cattle- rearing agricultural sector in Zimbabwe.A study was carried out in July 1996 to assess the potential of sorghum grain (high tannin) in high energy beef finishing diets. The effect of polyethylene glycol (PEG) on the utilization of sorghum grain based diets was also examined. Forty steers were blocked by weight and then randomly allocated to five treatments. One group was assigned to direct slaughter. The remaining groups were offered the following diets containing 33 percent grain: 1.100 percent maize (100M); 2.50 percent maize: 50 percent sorghum (50M:50S); 3.100 percent sorghum (100S);
4. 100 percent sorghum + 3g PEG per day (100S PEG). Dry matter and metabilizable energy (ME) intake were highest with 50M:50S and lowest (P<0.01) with the 100S PEG diet. Steers on the 50M:50S diet had the highest (P<0.05) growth rates and carcass gains. PEG did not improve the utilization of the high tannin sorghum grain
Understanding the dynamics of accessing chronic medicines in the public sector: Implications for policy in South Africa
Philosophiae Doctor - PhD (School of Public Health)Access to medicines (ATM), specifically for those medicines that are related to the priority
health needs of a population has been cited as a fundamental part of universal health coverage
and a key element for service delivery and high-quality care. Therefore, ensuring reliable
access to and appropriate use of safe, effective and affordable medicines is one of the core
functions of an effective health system. With the rising demand for treatment of chronic
diseases (e.g. HIV, diabetes and hypertension), ATM has increasingly received global
attention. Yet as of 2011, it was estimated that at least one third of the world's population had
no regular access to medicines. Globally, there is a dearth of in-depth country level evidence
to influence policy responses, coupled with inadequate understanding of how pharmaceutical
systems operate within broader health systems. This thesis comprises two main parts: 1) a
situational analysis of the state of chronic medicines provision in the public sector in the
Eastern Cape and Western Cape provinces of South Africa; and (2) an evaluation of an
existing ATM model in one province.
To situate this study within the ATM discourse, a conceptual framework was developed from
a review of empirical and theoretical literature. The framework incorporated six ATM
dimensions (availability, affordability, acceptability, accessibility, accommodation and
quality) and their interplay at multiple levels including: health facility, individual, household
and community levels. Then, at a health system level, the interaction of medicines (a health
system building block) with other building blocks (information, financing, human resources,
infrastructure and governance)