33 research outputs found
Soyabean response to rhizobium inoculation across sub-Saharan Africa: Patterns of variation and the role of promiscuity
Article purchased; Published online: 7 Sept 2017Improving bacterial nitrogen fixation in grain legumes is central to sustainable intensification of agriculture in sub-Saharan Africa. In the case of soyabean, two main approaches have been pursued: first, promiscuous varieties were developed to form effective symbiosis with locally abundant nitrogen fixing bacteria. Second, inoculation with elite bacterial strains is being promoted. Analyses of the success of these approaches in tropical smallholder systems are scarce. It is unclear how current promiscuous and non-promiscuous soyabean varieties perform in inoculated and uninoculated fields, and the extent of variation in inoculation response across regions and environmental conditions remains to be determined. We present an analysis of on-farm yields and inoculation responses across ten countries in Sub Saharan Africa, including both promiscuous and non-promiscuous varieties. By combining data from a core set of replicated on-farm trials with that from a large number of farmer-managed try-outs, we study the potential for inoculation to increase yields in both variety types and evaluate the magnitude and variability of response. Average yields were estimated to be 1343 and 1227 kg/ha with and without inoculation respectively. Inoculation response varied widely between trials and locations, with no clear spatial patterns at larger scales and without evidence that this variation could be explained by yield constraints or environmental conditions. On average, specific varieties had similar uninoculated yields, while responding more strongly to inoculation. Side-by side comparisons revealed that stronger responses were observed at sites where promiscuous varieties had superior uninoculated yields, suggesting the availability of compatible, effective bacteria as a yield limiting factor and as a determinant of the magnitude of inoculation response
Genetic determinants of fungi-induced ROS production are associated with the risk of invasive pulmonary aspergillosis
© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Reactive oxygen species (ROS) are an essential component of the host defense against fungal infections. However, little is known about how common genetic variation affects ROS-mediated antifungal host defense. In the present study, we investigated the genetic factors that regulate ROS production capacity in response to the two human fungal pathogens: Candida albicans and Aspergillus fumigatus. We investigated fungal-stimulated ROS production by immune cells isolated from a population-based cohort of approximately 200 healthy individuals (200FG cohort), and mapped ROS-quantitative trait loci (QTLs). We identified several genetic loci that regulate ROS levels (P < 9.99 × 10-6), with some of these loci being pathogen-specific, and others shared between the two fungi. These ROS-QTLs were investigated for their influence on the risk of invasive pulmonary aspergillosis (IPA) in a disease relevant context. We stratified hematopoietic stem-cell transplant (HSCT) recipients based on the donor's SNP genotype and tested their impact on the risk of IPA. We identified rs4685368 as a ROS-QTL locus that was significantly associated with an increased risk of IPA after controlling for patient age and sex, hematological malignancy, type of transplantation, conditioning regimen, acute graft-versus-host-disease grades III-IV, and antifungal prophylaxis. Collectively, this data provides evidence that common genetic variation can influence ROS production capacity, and, importantly, the risk of developing IPA among HSCT recipients. This evidence warrants further research for patient stratification based on the genetic profiling that would allow the identifications of patients at high-risk for an invasive fungal infection, and who would benefit the most from a preventive strategy.This study was supported by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 847507 (HDM-FUN). MGN was supported by an ERC Advanced grant (833247) and a Spinoza grant of the Netherlands Association for Scientific Research. VK was supported by a Research Grant [2017] of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and Hypatia tenure track grant. AC was supported by the Fundação para a Ciência e a Tecnologia (FCT) (UIDB/50026/2020 and UIDP/50026/2020), the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) (NORTE-01-0145-FEDER-000039), and the “la Caixa” Foundation (ID 100010434) and FCT under the agreement LCF/PR/HR17/52190003. CC was supported by FCT (CEECIND/04058/2018 and PTDC/SAU-SER/29,635/2017) and the Gilead Research Scholars Program – Antifungals. SMG was the recipient of a PhD fellowship funded by FCT (SFRH/BD/136,814/2018). MSG was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft - DFG) Emmy Noether Program (project no. 434385622/GR 5617/1-1).info:eu-repo/semantics/publishedVersio
Factors influencing willingness to participate in new drug trial studies: a study among parents whose children were recruited into these trials in northern Ghana
Modelling human choices: MADeM and decision‑making
Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)
A Study on the Performance of a Cascade Heat Pump for Generating Hot Water
The use of cascade heat pumps for hot water generation has gained much attention in recent times. The big question that has attracted much research interest is how to enhance the performance and energy saving potential of these cascade heat pumps. This study therefore proposed a new cycle to enhance performance of the cascade heat pump by adopting an auxiliary heat exchanger (AHX) in desuperheater, heater and parallel positions at the low stage (LS) side. The new cascade cycle with AHX in desuperheater position was found to have better performance than that with AHX at heater and parallel positions. Compared to the conventional cycle, heating capacity and coefficient of performance (COP) of the new cascade cycle with AHX in desuperheater position increased up to 7.4% and 14.9% respectively
A Critique of Prosperity Theology in the Context of Ghanaian Christianity
The economic situation in contemporary Ghana makes everyone yearn for economic progress. In Ghana, like many other parts of Africa, religion is responsible for providing the economic, spiritual, and health needs of its adherents. The predominantly Christian population in Ghana makes many people look up to Christianity to provide the road map to the country’s success. In this regard, the prosperity theology/gospel is the most dominant approach to seeking health and wealth among Ghanaian Christians. Though very persuasive, prosperity theology prompts so much debate about its influence on the religious and socio-economic life of Christians and the society at large. On the one hand, it is considered as promoting unethical behaviour and failing to yield qualitative growth for the church. On the other hand, it is considered as attracting a large following to the Christian faith. The need to evaluate the impact of this type of teaching is an urgent theological and pastoral concern because it is the most appealing Christian approach to socio-economic breakthrough for contemporary Ghanaian Christians. This paper, therefore, sought to address the problem of the lack of a balanced assessment of the prosperity gospel and how its weaknesses can be addressed. The study is a literature-based research that gathered data from publications on the subject matter. Through a critical analysis and evaluation of the information gathered, the authors evaluated the overall impact of the prosperity theology on the holistic life (social, spiritual, economic and political) of its adherents and having noted some pitfalls, recommended how this popular theology can be refined. Apart from providing guidelines for addressing the challenges associated with the prosperity theology, the paper also has the potential of yielding ethical renewal for people to live responsibly as they work toward improving their socio-economic and spiritual lives
Refrigerant Charge Fault Detection and Diagnosis Algorithm for Water-to-Water Heat Pump Unit
Refrigerant charge faults have a great adverse effect on the performance of heat pumps and must therefore be detected and diagnosed early in real time. In this study, the effect of refrigerant charge faults on a water-to-water heat pump is experimentally investigated in cooling mode and heating mode at various outdoor entering water temperature conditions. The study showed that refrigerant undercharge affects the performance of water-to-water heat pump more in heating mode than in cooling mode. Results from the study are used to develop a refrigerant charge fault detection and diagnosis (FDD) algorithm that works using correlations and rule-based refrigerant fault characteristic charts. The FDD algorithm is able to detect refrigerant charge faults in the water-to-water heat pump within an error threshold of ±4.5% and ±1.1% in cooling mode and heating mode respectively
Refrigerant Charge Fault Detection and Diagnosis Algorithm for Water-to-Water Heat Pump Unit
Analysis of indoor set-point temperature of split-type ACs on thermal comfort and energy savings for office buildings in hot-humid climates
In hot-humid climates, particularly in sub-Saharan Africa (SSA), ambient temperatures and relative humidity are as high as 35 °C and 84%, respectively, requiring the use of mechanical cooling systems for indoor thermal comfort. Split-type vapor-compression air-conditioners (SVAC) are mainly used for space cooling in SSA and consume 60–80% of total energy consumption in commercial and public buildings. Appropriate control strategy of the indoor set-point temperature of SVAC can result in significant energy savings in these buildings. In this study, modeling and dynamic simulation have been conducted using EnergyPlus to predict the energy saving potential and indoor thermal comfort of buildings in hot-humid climates by controlling set-point temperature of the SVAC. In a case study, climatic data for Ghana, was used to predict the energy saving potential and indoor thermal comfort. The study results revealed that, to ensure indoor thermal comfort at high outdoor temperature condition of 35 °C, the least and optimum set-point temperatures of the SVAC should be 21 °C and 25 °C, respectively. On the other hand, for low outdoor temperature condition, the least and optimum set-point temperatures were 22 °C and 26 °C, respectively. Considering 1-star and 2-star rated SVACs which are dominantly used in Ghana, operating at 21–25 °C in the case of high outdoor conditions, and 22–26 °C for low outdoor conditions relative to the least temperatures resulted in energy savings of 8–33% and 12-44%, respectively
Fault Detection Methodology for Secondary Fluid Flow Rate in a Heat Pump Unit
Fault detection and diagnosis (FDD) has become an important subject in heat pumps due to its potential for energy savings. However, research on multiple faults occurring at the secondary fluid side of heat pumps is rare in the open literature. This study experimentally examined single secondary fluid flow rate faults (SSFF) and multiple-simultaneous secondary fluid flow rate faults (MSSFF) and their effects on the performance of a heat pump unit, which is a core component of ground source heat pump systems, and proposed FDD methodology to detect these faults. The secondary fluid flow rate faults were simulated in cooling mode by varying the evaporator and condenser secondary fluid flow rates at 60%, 80%, 100%, 120%, and 140% of the reference value according to varying outdoor entering water temperature conditions. Condenser secondary fluid flow rate faults affected the heat pump coefficient of performance(COP) significantly more than the evaporator secondary fluid flow rate fault in SSFF. Cooling capacity was highly dependent on the evaporator secondary fluid flow rate fault while COP was greatly affected by the condenser secondary fluid flow rate fault in MSSFF. The FDD methodology was modeled using correlations and performance trends of the heat pump and can detect SSFF and MSSFF within an error threshold of ±1.6% and ±6.4% respectively