106 research outputs found
An Intercomparison of Satellite-Based Daily Evapotranspiration Estimates under Different Eco-Climatic Regions in South Africa
Knowledge of evapotranspiration (ET) is essential for enhancing our understanding of the hydrological cycle, as well as for managing water resources, particularly in semi-arid regions. Remote sensing offers a comprehensive means of monitoring this phenomenon at different spatial and temporal intervals. Currently, several satellite methods exist and are used to assess ET at various spatial and temporal resolutions with various degrees of accuracy and precision. This research investigated the performance of three satellite-based ET algorithms and two global products, namely land surface temperature/vegetation index (TsVI), Penman–Monteith (PM), and the Meteosat Second Generation ET (MET) and the Global Land-surface Evaporation: the Amsterdam Methodology (GLEAM) global products, in two eco-regions of South Africa. Daily ET derived from the eddy covariance system from Skukuza, a sub-tropical, savanna biome, and large aperture boundary layer scintillometer system in Elandsberg, a Mediterranean, fynbos biome, during the dry and wet seasons, were used to evaluate the models. Low coefficients of determination (R2) of between 0 and 0.45 were recorded on both sites, during both seasons. Although PM performed best during periods of high ET at both sites, results show it was outperformed by other models during low ET times. TsVI and MET were similarly accurate in the dry season in Skukuza, as GLEAM was the most accurate in Elandsberg during the wet season. The conclusion is that none of the models performed well, as shown by low R2 and high errors in all the models. In essence, our results conclude that further investigation of the PM model is possible to improve its estimation of low ET measurements
ESTABLISHING A PLATFORM FOR SPRAY DRYING INHALABLE VACCINES IN SOUTH AFRICA
Mycobacterium bovis BCG is the current vaccine for tuberculosis (TB). However, BCG as it is currently administered shows highly variable efficacy in protecting adults against TB. The natural route of infection of TB is via inhalation of bacilli-containing aerosols and it is postulated that immunization by the natural route of infection may lead to a greater immunity given the fact that the lungs are the primary target of infection. By eliciting both local and systemic immune responses, it is anticipated that an inhaled form of BCG will offer greater protection against pulmonary TB.
Current commercial BCG vaccine preparations are filled as bacterial suspensions in vials, dried through lyophilization and stabilized through refrigeration with a one year shelf life. However, freeze-dried BCG does not exhibit a particle form conducive for delivery via the aerosol route and must be injected. Spray drying studies by Harvard University and Medicine in Need (MEND) scientists have demonstrated that BCG could be spray dried into a viable aerosol with up to 1 year of stability under refrigerated conditions, with the potential for room temperature stability.
To support the further preclinical development of the BCG aerosol for application in the developing world, MEND established a state-of-the-art Biosafety level 3 spray drying facility with local expertise in South Africa, where the vaccine will be produced for an IND-enabling toxicology study meeting OECD Good Laboratory Practice (GLP) requirements. Frozen BCG bulk is spray dried and the resulting dry powder is characterized in terms of viability and aerosol properties. The dried BCG aerosol is then aseptically filled into capsules using a semi-automatic filling device for delivery using a low-cost hand-held inhaler.
In conclusion, the spray drying technology was successfully transferred from Harvard University to the MEND facility in Pretoria. MEND is developing local expertise and infrastructure to support further preclinical and clinical development of BCG for inhalation
Relationships between farmer psychological profiles and farm business performance amongst smallholder beef and poultry farmers in South Africa
Beef cattle and poultry are critically important livestock for improving household food security and alleviating poverty amongst smallholder farmers in South Africa. In this paper, our goal is to examine the relationships between farmer psychological profiles and farm business performance of commercially oriented beef cattle and poultry smallholder farmers in South Africa. We employ a multipronged interdisciplinary approach to test the theory of planned behaviour and its relationship to farm business performance. First, a behavioural science-informed survey instrument was employed to collect data from randomly selected farmer participants in two major beef and poultry projects undertaken by the authors. Second, a latent profile analysis was used to identify the psychological profiles of those farmers. Third, traditional and estimated indicators of farm business performance were obtained using descriptive and econometric-based approaches, including logistic regression and stochastic frontier analyses. The estimated farm business performance indicators were correlated with the psychological profiles of farmers. Results from the latent profile analysis showed three distinct profiles of beef and poultry farmers clearly differentiated by their ability to control and succeed in their farm business enterprises; criteria included attitude, openness to ideas, personality, perceived capabilities, self-efficacy, time orientation, and farm- and personal-related concerns. Profile 1 (‘Fatalists’) scored themselves negatively on their ability to control and succeed in their business enterprises. The majority of farmers were generally neutral about their ability to control and succeed in their businesses (Profile 2, ‘Traditionalists’), while a relatively small group of farmers were confident of their ability to succeed (Profile 3, ‘Entrepreneurs’). We found evidence of significant differences in farm business performance amongst the different profiles of farmers. As far as we can determine, this is the only study to have assessed farm business performance based on a differentiation of farmers’ psychological profiles. Our results provide a framework to further investigate whether particular types of on-farm interventions and training methods can be customised for different segments of farmers based on their preferred learning styles
ESSENTIAL OIL COMPOSITION OF ARTEMISIA VULGARIS GROWN IN EGYPT
Objective: The objective of this research was to evaluate the significance of the plant's origin and to assess the essential oil composition of Artemisia vulgaris grown in Egypt simultaneously evaluating the effect of environmental conditions on essential oil composition.Methods: Seeds were planted and the essential oils extracted, using hydrodistillation, from the plants that grew. The resulting essential oils were examined, using gas chromatography linked to mass spectrometry (GC-MS). Thus also evaluating the essential oil chemotype fingerprint†in A. vulgarisResults:  The study identified: the most abundant compounds being camphor, 3, 5-dimethylcyclohexane, germacrene D, cubebene, yomogi alcohol, artemisia alcohol, caryophyllene, while is lower concentrations thujopsene, muurolene, borneol, terpinen-4-ol, valencene, elemene and humulene. Despite the origins of the seeds, the chemical profile was very similar to those of plants grown in Egypt, thus suggesting essential oil composition was significantly influenced by the environmental conditions.Conclusion: Based on the present study, It is suggested that seed origin may play a less significant part if the seed is planted in an environment different to that of its origin, this study proved that and favors the plant-environment interaction to influence the secondary metabolite composition. This supports that plant metabolite profiles are greatly affected by the environment they are grown in.Â
Recommendations for dealing with waste contaminated with Ebola virus: a Hazard Analysis of Critical Control Points approach
Objective To assess, within communities experiencing Ebola virus outbreaks, the risks associated with the disposal of human waste and to generate recommendations for mitigating such risks. Methods A team with expertise in the Hazard Analysis of Critical Control Points framework identified waste products from the care of individuals with Ebola virus disease and constructed, tested and confirmed flow diagrams showing the creation of such products. After listing potential hazards associated with each step in each flow diagram, the team conducted a hazard analysis, determined critical control points and made recommendations to mitigate the transmission risks at each control point. Findings The collection, transportation, cleaning and shared use of blood-soiled fomites and the shared use of latrines contaminated with blood or bloodied faeces appeared to be associated with particularly high levels of risk of Ebola virus transmission. More moderate levels of risk were associated with the collection and transportation of material contaminated with bodily fluids other than blood, shared use of latrines soiled with such fluids, the cleaning and shared use of fomites soiled with such fluids, and the contamination of the environment during the collection and transportation of blood-contaminated waste. Conclusion The risk of the waste-related transmission of Ebola virus could be reduced by the use of full personal protective equipment, appropriate hand hygiene and an appropriate disinfectant after careful cleaning. Use of the Hazard Analysis of Critical Control Points framework could facilitate rapid responses to outbreaks of emerging infectious disease
Phytochemicals in prostate cancer: From bioactive molecules to upcoming therapeutic agents
Prostate cancer is a heterogeneous disease, the second deadliest malignancy in men and the most commonly diagnosed cancer among men. Traditional plants have been applied to handle various diseases and to develop new drugs. Medicinal plants are potential sources of natural bioactive compounds that include alkaloids, phenolic compounds, terpenes, and steroids. Many of these naturally-occurring bioactive constituents possess promising chemopreventive properties. In this sense, the aim of the present review is to provide a detailed overview of the role of plant-derived phytochemicals in prostate cancers, including the contribution of plant extracts and its corresponding isolated compounds.This work was supported by CONICYT PIA/APOYO CCTE AFB170007. N. Martins would like to thank the Portuguese Foundation for Science and Technology (FCT–Portugal) for the Strategic project ref. UID/BIM/04293/2013 and “NORTE2020 - Programa Operacional Regional do Norte” (NORTE-01-0145-FEDER-000012) and C. F. Rodrigues for the UID/EQU/00511/2019 Project—Laboratory of Process Engineering, Environment, Biotechnology, and Energy—LEPABE financed by national funds through FCT/MCTES (PIDDAC)
Persistent Chlamydia trachomatis, Neisseria gonorrhoeae or Trichomonas vaginalis positivity after treatment among human immunodeficiency virus-infected pregnant women, South Africa
The objective of this study is to assess the predictors and frequency of persistent sexually transmitted infection (STI) positivity in human immunodeficiency virus (HIV)-infected pregnant women treated for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) or Trichomonas vaginalis (TV) infection. We enrolled HIV-infected pregnant women attending their first antenatal care visit and tested them for urogenital CT, NG and TV infection using Xpert® CT/NG and TV assays (Cepheid, Sunnyvale, CA). Those testing positive were treated. Participants either notified partners to seek treatment or were given extra medication to deliver to partners for treatment. Repeat testing was conducted approximately 21 days post-treatment or treatment initiation. Among 427 participants, 172 (40.3%) tested positive for any STI. Of the 136 (79.1%) that returned for repeat testing, 36 (26.5%) tested positive for the same organism: CT = 27 (26.5%), NG = 1 (6.3%), TV = 11 (16.7%). Persistent CT positivity was independently associated with having more than one sex partner in the preceding 12 months (adjusted-prevalence ratio [aPR] = 3.03, 95% CI: 1.44–6.37) and being newly diagnosed with HIV infection during the first antenatal care visit compared to those currently on antiretroviral therapy (aPR = 3.97, 95% CI: 1.09–14.43). Persistent TV positivity was associated with not knowing if a partner sought treatment following STI disclosure (aPR = 12.6, 95% CI: 2.16–73.5) and prior diagnosis of HIV but not currently on antiretroviral therapy. (aPR = 4.14; 95% CI: 1.25–13.79). We identified a high proportion of HIV-infected pregnant women with persistent CT or TV positivity after treatment. To decrease the risk of re-infection, enhanced strategies for partner treatment programmes are needed to improve the effectiveness of STI screening and treatment in pregnancy. The relationship between not being on antiretroviral therapy and persistent STI positivity needs further study.The Eunice Kennedy Shriver Institute of Child Health and Human Development, National Institutes of Health (NIH), award R21HD084274 and the President’s Emergency Plan for AIDS Relief through the United States Agency of the Cooperative Agreement AID 674-A-12-00017 funded this study. Noah Kojima was supported by the U.S. NIH Fogarty International Center (award number D43TW009343) and the University of California Global Health Institute. Christina A Muzny was supported by K23AI106957-01A1 from the National Institute of Allergy and Infectious Diseases.https://journals.sagepub.com/home/stdhj2021Medical MicrobiologyPaediatrics and Child Healt
Earth observation for sustainable urban planning in developing countries: needs, trends, and future directions
Abstract: Cities are constantly changing and authorities face immense challenges in obtaining accurate and timely data to effectively manage urban areas. This is particularly problematic in the developing world where municipal records are often unavailable or not updated. Spaceborne earth observation (EO) has great potential for providing up-to-date spatial information about urban areas. This article reviews the application of EO for supporting urban planning. In particular, the article overviews case studies where EO was used to derive products and indicators required by urban planners. The review concludes that EO has sufficiently matured in recent years but that a shift from the current focus on purely science-driven EO applications to the provision of useful information for day-to-day decision-making and urban sustainability monitoring is clearly needed
Standardization of Clinical Assessment and Sample Collection Across All PERCH Study Sites.
BACKGROUND.: Variable adherence to standardized case definitions, clinical procedures, specimen collection techniques, and laboratory methods has complicated the interpretation of previous multicenter pneumonia etiology studies. To circumvent these problems, a program of clinical standardization was embedded in the Pneumonia Etiology Research for Child Health (PERCH) study. METHODS.: Between March 2011 and August 2013, standardized training on the PERCH case definition, clinical procedures, and collection of laboratory specimens was delivered to 331 clinical staff at 9 study sites in 7 countries (The Gambia, Kenya, Mali, South Africa, Zambia, Thailand, and Bangladesh), through 32 on-site courses and a training website. Staff competency was assessed throughout 24 months of enrollment with multiple-choice question (MCQ) examinations, a video quiz, and checklist evaluations of practical skills. RESULTS.: MCQ evaluation was confined to 158 clinical staff members who enrolled PERCH cases and controls, with scores obtained for >86% of eligible staff at each time-point. Median scores after baseline training were ≥80%, and improved by 10 percentage points with refresher training, with no significant intersite differences. Percentage agreement with the clinical trainer on the presence or absence of clinical signs on video clips was high (≥89%), with interobserver concordance being substantial to high (AC1 statistic, 0.62-0.82) for 5 of 6 signs assessed. Staff attained median scores of >90% in checklist evaluations of practical skills. CONCLUSIONS.: Satisfactory clinical standardization was achieved within and across all PERCH sites, providing reassurance that any etiological or clinical differences observed across the study sites are true differences, and not attributable to differences in application of the clinical case definition, interpretation of clinical signs, or in techniques used for clinical measurements or specimen collection
- …