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result(s) for
"Quansah, Emmanuel"
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Optimal Temporal Filtering of the Cosmic-Ray Neutron Signal to Reduce Soil Moisture Uncertainty
by
Quansah, Emmanuel
,
Bogena, Heye Reemt
,
Amekudzi, Leonard Kofitse
in
Agricultural production
,
Agriculture
,
Atmospheric pressure
2022
Cosmic ray neutron sensors (CRNS) are increasingly used to determine field-scale soil moisture (SM). Uncertainty of the CRNS-derived soil moisture strongly depends on the CRNS count rate subject to Poisson distribution. State-of-the-art CRNS signal processing averages neutron counts over many hours, thereby accounting for soil moisture temporal dynamics at the daily but not sub-daily time scale. This study demonstrates CRNS signal processing methods to improve the temporal accuracy of the signal in order to observe sub-daily changes in soil moisture and improve the signal-to-noise ratio overall. In particular, this study investigates the effectiveness of the Moving Average (MA), Median filter (MF), Savitzky–Golay (SG) filter, and Kalman filter (KF) to reduce neutron count error while ensuring that the temporal SM dynamics are as good as possible. The study uses synthetic data from four stations for measuring forest ecosystem–atmosphere relations in Africa (Gorigo) and Europe (SMEAR II (Station for Measuring Forest Ecosystem–Atmosphere Relations), Rollesbroich, and Conde) with different soil properties, land cover and climate. The results showed that smaller window sizes (12 h) for MA, MF and SG captured sharp changes closely. Longer window sizes were more beneficial in the case of moderate soil moisture variations during long time periods. For MA, MF and SG, optimal window sizes were identified and varied by count rate and climate, i.e., estimated temporal soil moisture dynamics by providing a compromise between monitoring sharp changes and reducing the effects of outliers. The optimal window for these filters and the Kalman filter always outperformed the standard procedure of simple 24-h averaging. The Kalman filter showed its highest robustness in uncertainty reduction at three different locations, and it maintained relevant sharp changes in the neutron counts without the need to identify the optimal window size. Importantly, standard corrections of CRNS before filtering improved soil moisture accuracy for all filters. We anticipate the improved signal-to-noise ratio to benefit CRNS applications such as detection of rain events at sub-daily resolution, provision of SM at the exact time of a satellite overpass, and irrigation applications.
Journal Article
Targeting energy metabolism via the mitochondrial pyruvate carrier as a novel approach to attenuate neurodegeneration
2018
Several molecular pathways are currently being targeted in attempts to develop disease-modifying therapies to slow down neurodegeneration in Parkinson’s disease. Failure of cellular energy metabolism has long been implicated in sporadic Parkinson’s disease and recent research on rare inherited forms of Parkinson’s disease have added further weight to the importance of energy metabolism in the disease pathogenesis. There exists a new class of anti-diabetic insulin sensitizers in development that inhibit the mitochondrial pyruvate carrier (MPC), a protein which mediates the import of pyruvate across the inner membrane of mitochondria. Pharmacological inhibition of the MPC was recently found to be strongly neuroprotective in multiple neurotoxin-based and genetic models of neurodegeneration which are relevant to Parkinson’s disease. In this review, we summarize the neuroprotective effects of MPC inhibition and discuss the potential putative underlying mechanisms. These mechanisms involve augmentation of autophagy via attenuation of the activity of the mammalian target of rapamycin (mTOR) in neurons, as well as the inhibition of neuroinflammation, which is at least partly mediated by direct inhibition of MPC in glia cells. We conclude that MPC is a novel and potentially powerful therapeutic target that warrants further study in attempts to slow Parkinson’s disease progression.
Journal Article
Social Factors Influencing Child Health in Ghana
by
Karikari, Thomas K.
,
Quansah, Emmanuel
,
Mireku, Michael Osei
in
Analysis
,
Child
,
Child health
2016
Social factors have profound effects on health. Children are especially vulnerable to social influences, particularly in their early years. Adverse social exposures in childhood can lead to chronic disorders later in life. Here, we sought to identify and evaluate the impact of social factors on child health in Ghana. As Ghana is unlikely to achieve the Millennium Development Goals' target of reducing child mortality by two-thirds between 1990 and 2015, we deemed it necessary to identify social determinants that might have contributed to the non-realisation of this goal.
ScienceDirect, PubMed, MEDLINE via EBSCO and Google Scholar were searched for published articles reporting on the influence of social factors on child health in Ghana. After screening the 98 articles identified, 34 of them that met our inclusion criteria were selected for qualitative review.
Major social factors influencing child health in the country include maternal education, rural-urban disparities (place of residence), family income (wealth/poverty) and high dependency (multiparousity). These factors are associated with child mortality, nutritional status of children, completion of immunisation programmes, health-seeking behaviour and hygiene practices.
Several social factors influence child health outcomes in Ghana. Developing more effective responses to these social determinants would require sustainable efforts from all stakeholders including the Government, healthcare providers and families. We recommend the development of interventions that would support families through direct social support initiatives aimed at alleviating poverty and inequality, and indirect approaches targeted at eliminating the dependence of poor health outcomes on social factors. Importantly, the expansion of quality free education interventions to improve would-be-mother's health knowledge is emphasised.
Journal Article
Methane emissions from rice cultivation in West Africa and compensation options from nature reserve forests
by
Ogunjobi, Kehinde
,
Frempong, Alex
,
Spangenberg, Ines
in
agriculture
,
Climate change
,
Cultivation
2025
Methane (CH4) is a major and potent greenhouse gas (GHG), and its emissions from agricultural activities, particularly rice cultivation, are a significant concern for climate change. Due to the high demand for food security, driven by rapid population growth and national initiatives to reduce dependency on rice imports, rice cultivation is intensified in West Africa. However, its contribution to atmospheric CH4 remains largely unknown. Here, for the first time, cutting-edge eddy covariance tower measurements were conducted parallelly in a rice field (Janga) and a reserve forest (Mole National Park), both located in the Guinea savanna region of West Africa. Using CH4 measurement data from June to October 2023 (rice cultivation period), the dynamic interplay between methane emissions from rice cultivation and its potential mitigation through forest methane uptake was assessed. Our results show that the rice field acted as a net source of CH4 at a rate of 2037 mgCH4m−2, whereas the most intense flooded period (August) accounted for 70% of the total emissions. On the other hand, the forest reserve acted as a sink, with a net uptake of −560 mgCH4m−2, and the highest uptake observed in October. Accounting for the global warming potential (GWP) of CH4 over a 20 year period, the forest had a wet season negative GWP of −47.04 gCO2eq, while the rice field emitted CH4 of 171.36 gCO2eq. This implies that under similar conditions during the measurement campaigns, the forest per square area needs approximately a factor of ∼4 to balance the positive radiative effect per square area of rice cultivated. This work emphasizes the need to integrate forests to compensate for methane released by rice cultivation in the semi-arid West African savannah region.
Journal Article
Spatial analysis of drought vulnerability in cocoa agroforestry systems across the Ghana-Togo border
2025
Extreme events like droughts frequently affect West Africa, known as the world’s centre for cocoa production. In Ghana and Togo, these extreme events negatively affect water supplies and agricultural land productivity, especially for cocoa. This study aims to create a cocoa drought vulnerability map that offers a clearer perspective of drought effects over the transboundary territory between Ghana and Togo, where substantial amounts of cocoa are produced. The vulnerability map used 16 criteria categorised under three (3) vulnerability components Exposure [4], Sensitivity [6], and Adaptive Capacity [6]. The study used the Intergovernmental Panel on Climate Change (IPCC) vulnerability framework and the Analytical Hierarchy Process (AHP) to normalise the criteria. Results showed that over 70% of the cocoa cultivation area in the study area is moderately to highly vulnerable to drought, while less than 30% is classified as very low and low. The most susceptible areas are located on the Togolese side, extending from the central to the northern region, compared to Ghana. These findings are relevant to support drought resilience strategies in the cocoa sector aiming to prioritise interventions and maximise cocoa productivity per drought vulnerability category zone.
Journal Article
A novel automated morphological analysis of Iba1+ microglia using a deep learning assisted model
by
Jones, Russell G
,
George, Sonia
,
Stetzik, Lucas
in
Animal models
,
Antibodies
,
Artificial intelligence
2022
There is growing evidence for the key role of microglial functional state in brain pathophysiology. Consequently, there is a need for efficient automated methods to measure the morphological changes distinctive of microglia functional states in research settings. Currently, many commonly used automated methods can be subject to sample representation bias, time consuming imaging, specific hardware requirements and difficulty in maintaining an accurate comparison across research environments. To overcome these issues, we use commercially available deep learning tools Aiforia® Cloud (Aifoira Inc., Cambridge, United States) to quantify microglial morphology and cell counts from histopathological slides of Iba1 stained tissue sections. We provide evidence for the effective application of this method across a range of independently collected datasets in mouse models of viral infection and Parkinson’s disease. Additionally, we provide a comprehensive workflow with training details and annotation strategies by feature layer that can be used as a guide to generate new models. In addition, all models described in this work are available within the Aiforia® platform for study-specific adaptation and validation.
Journal Article
Tet2 loss and enhanced ciliogenesis suppress α-synuclein pathology
by
Marshall, Lee L.
,
Aguileta, Miguel
,
Milčiūtė, Milda
in
Aged
,
alpha-Synuclein - metabolism
,
Animals
2025
There are no approved treatments that slow Parkinson’s disease (PD) progression and therefore it is important to identify novel pathogenic mechanisms that can be targeted. Loss of the epigenetic marker,
Tet2
appears to have some beneficial effects in PD models, but the underlying mechanism of action is not well understood. We performed an unbiased transcriptomic analysis of cortical neurons isolated from patients with PD to identify dysregulated pathways and determine their potential contributions to the disease process. We discovered that genes associated with primary cilia, non-synaptic sensory and signaling organelles, are upregulated in both early and late stage PD patients. Enhancing ciliogenesis in primary cortical neurons via sonic hedgehog signaling suppressed the accumulation of α-synuclein pathology in vitro. Interestingly, deletion of
Tet2
in mice also enhanced the expression of primary cilia and sonic hedgehog signaling genes and reduced the accumulation of α-synuclein pathology and dopamine neuron degeneration in vivo. Our findings demonstrate the crucial role of TET2 loss in regulating ciliogenesis and potentially affecting the progression of PD pathology.
Journal Article
Cocoa Farmers’ Perceptions of Drought and Adaptive Strategies in the Ghana–Togo Transboundary Cocoa Belt
by
Bessah, Enoch
,
Nehren, Udo
,
Quansah, Emmanuel
in
Adaptation
,
adaptation strategies
,
Agricultural practices
2024
This study investigated the perception of drought by cocoa farmers and explored the effectiveness of adaptive strategies (ASs) used in smallholding farms in the transboundary region between Ghana and Togo. Drought significantly threatens cocoa production in this region, affecting farmers’ livelihoods and cocoa supply chains. This study used a multistage sampling approach, which involved surveys with questionnaires administered to 330 cocoa farmers throughout the study area, along with on-site observations. Statistical analysis included binary logistic and Poisson regression models to explore the relationship between farmer socioeconomic characteristics and adaptation practices. The findings revealed that cocoa farmers in the region have a nuanced understanding of drought, attributed to changing climatic patterns and unsustainable land management practices such as deforestation. To mitigate its impacts, farmers employ a variety of ASs, including investment in farm management, soil management, and intercropping with crop diversification. Furthermore, socioeconomic factors, including age, formal education, household size, land tenure right, adaptation cost assessment, and an underestimation of self-efficacy, were shown to affect the choice in the AS. Among the ASs adopted, only farm management practices (weeding, pruning, fertilizer application, etc.) significantly improved the cocoa yield. This study contributes to understanding drought as a critical issue for cocoa farmers and the adaptation practices used by smallholder cocoa farmers. Given that among the strategies adopted, only farm management practices, also known as good agricultural practices (GAPs), significantly improves yield, this study recommends well-designed and innovative packages of sustainable farm management based on farm and owner characteristics. These include irrigation schemes, timely soil fertilizer monitoring and supply, and the provision of drought-resistant varieties along with technical itineraries. Additional interventions require drought emergency responses, with other factors such as education and financial support mechanisms expected to improve farmers’ timely decision-making to adapt and improve cocoa production resilience to drought episodes in international transboundary regions with complex governance structures.
Journal Article
The concept of alpha-synuclein as a prion-like protein: ten years after
by
Brundin, Patrik
,
Quansah, Emmanuel
,
Steiner, Jennifer A
in
Axons
,
Cell culture
,
Dopamine receptors
2018
Parkinson’s disease is characterized by the loss of nigrostriatal dopaminergic signaling and the presence of alpha-synuclein aggregates (also called Lewy bodies and neurites) throughout the brain. In 2003, Braak and colleagues created a staging system for Parkinson’s disease describing the connection between the alpha-synuclein pathology and disease severity. Later, they suggested that the pathology might initially be triggered by exogenous insults targeting the gut and olfactory system. In 2008, we and other groups documented Lewy pathology in grafted neurons in people with Parkinson’s disease who had been transplanted over a decade prior to autopsy. We proposed that the Lewy pathology in the grafted neurons was the result of permissive templating or prion-like spread of alpha-synuclein pathology from neurons in the host to those in the grafts. During the following ten years, several studies described the transmission of alpha-synuclein pathology between neurons, both in cell culture and in experimental animals. Recent research has also begun to identify underlying molecular mechanisms. Collectively, these experimental studies tentatively support the idea that the progression from one Braak stage to the next is the consequence of prion-like propagation of Lewy pathology. However, definitive proof that intercellular propagation of alpha-synuclein pathology occurs in Parkinson’s disease cases has proven difficult to secure. In this review, we highlight several open questions that currently prevent us from concluding with certainty that prion-like transfer of alpha-synuclein contributes to the progression of Parkinson’s disease.
Journal Article
Serum leptin levels in patients with chronic kidney disease and hypertensive heart disease: An observational cross‐sectional study
by
Mohammed, Bismark N.
,
Amanquah, Seth D.
,
Boima, Vincent
in
Adipocytes
,
Blood pressure
,
body mass index
2023
Background and Aim
Adipocytes secrete a peptide hormone called leptin, which plays a crucial role in controlling appetite and energy expenditure. Alterations in leptin concentrations are associated with CKD‐related cardiovascular problems such as hypertensive heart disease (HHD). Despite the link, data on the precise function of leptin in people with CKD and HHD is scant.
Methods
An observational cross‐sectional study involving a total of 108 participants (72 CKD patients with HHD and 36 healthy controls). Their demographic and anthropometric information was collected using a standardized questionnaire. Certain clinical measures such as blood pressure and body mass index (BMI) were assessed. Fasting blood samples were analyzed for levels of plasma glucose (FPG), lipids, creatinine, and leptin. Data were analyzed with SPSS v23.
Results
Leptin, FPG, creatinine and triglyceride levels were all significantly higher in CKD patients with HHD compared to controls (p < 0.01 for all). Furthermore, advanced CKD status (being in stage 5), having a 6‐year diagnosis of HHD, being female, having a higher BMI, and elevation in levels of HDL and FPG contributed significantly to the variance in serum leptin levels in the case group (β = 0.37, 0.22, 0.19, 0.18, 0.27, 0.28; p < 0.05 for all). In the control group, the female gender had the biggest unique effect on circulating leptin levels, followed by BMI and eGFR (β = 0.71, 0.34, −0.22; p < 0.01 for all).
Conclusion
Patients with CKD who also had HHD reported considerably higher circulating leptin levels. Significantly higher blood leptin levels were shown to be associated with CKD stage 5 in the case group. These results are consistent with the role of leptin in the metabolic complexity seen in CKD patients. There needs to be more research into treatments that aim to lower leptin levels in CKD patients with HHD.
Journal Article