Test of validity of a dynamic soil carbon model using data from leaf litter decomposition in a West African tropical forest

Abstract. We evaluated the applicability of the dynamic soil carbon model Yasso07 in tropical conditions in West Africa by simulating the litter decomposition process using as required input into the model litter mass, litter quality, temperature and precipitation collected during a litterbag experiment. The experiment was conducted over a six-month period on leaf litter of five dominant tree species, namely Afzelia africana, Anogeissus leiocarpa, Ceiba pentandra, Dialium guineense and Diospyros mespiliformis in a semi-deciduous vertisol forest in Southern Benin. Since the predictions of Yasso07 were not consistent with the observations on mass loss and chemical composition of litter, Yasso07 was fitted to the dataset composed of global data and the new experimental data from Benin. The re-parameterized versions of Yasso07 had a good predictive ability and refined the applicability of the model in Benin to estimate soil carbon stocks, its changes and CO2 emissions from heterotrophic respiration as main outputs of the model. The findings of this research support the hypothesis that the high variation of litter quality observed in the tropics is a major driver of the decomposition and needs to be accounted in the model parameterization. </jats:p

Point-of-Care Ultrasound for Tuberculosis Management in Sub-Saharan Africa-A Balanced SWOT Analysis.

Point-of-care ultrasound (POCUS) is an increasingly accessible skill, allowing for the decentralization of its use to non-specialist healthcare workers to guide routine clinical decision making. The advent of ultrasound-on-a-chip has transformed the technology into a portable mobile health device. Due to its high sensitivity to detect small consolidations, pleural effusions and sub pleural nodules, POCUS has recently been proposed as a sputum-free likely triage tool for tuberculosis (TB). To make an objective assessment of the potential and limitations of POCUS in routine TB management, we present a Strengths, Weaknesses, Opportunities & Threats (SWOT) analysis based on a review of the relevant literature and focusing on Sub-Saharan Africa (SSA). We idenitified numerous strengths and opportunities of POCUS for TB management e.g.; accessible, affordable, easy to use & maintain, expedited diagnosis, extra-pulmonary TB detection, safer pleural/pericardial puncture, use in children/pregnant women/PLHIV, targeted screening of TB contacts, monitoring TB sequelae, and creating AI decision support. Weaknesses and external threats such as operator dependency, lack of visualization of central lung pathology, poor specificity, lack of impact assessments and data from Sub-Saharan Africa must be taken into consideration to ensure that the potential of the technology can be fully realized in research as in practice

Variation in carbon budget, diversity and demography trends of selected tree populations of Wari Maro Forest Reserve between 2009-2014

Illegal timber logging and bush fire in tropical savanna woodlands create an uncontestable mortgage for climate change mitigation. To investigate this hypothesis, we proposed a three-dimensional methodology based on a diachronic analysis to establish half-decade changes in floristic diversity and carbon budget. Data on trees and stump density, diameter at breast height, tree heights and crown diameter were collected from all trees whose diameters equal or exceed 10 cm at the breast height. And these were investigated from a permanent plot of 1 ha set up in savanna-woodland vegetation. With these data, diversity index, crown cover of trees, biomass and carbon budget were estimated. Dynamics of these structural descriptors and demography of tree-populations with a special focus on tree logging, mortality and recruitment rates were considered with the aim of appraising how deforestation contributes to emission of greenhouse gases. Key outcomes of this research revealed that from 2009 to 2014, the woody average species’ richness of the Wari Maro Forest Reserve dropped from 15 to 14 species per hectare. The Shannon &amp; Wiener diversity index and the equitability index of Pielou were almost invariable. Conversely, considerable changes were observed as regard to tree density, basal area, crown cover and carbon pool. Occurred modifications were negative for species coveted for their timbers, and positive for species less desired for timbers as well as for fire-resistant species. A huge loss in both trees density and carbon budget was observed with Daniellia oliveri timber which is not even yet subjected to logging. As compared to natural tree mortality and recruitment rate, the timber logging rate makes the fight against illegal timber logging as the sine qua non condition for expecting reduction of emission from deforestation and forest degradation in tropical savanna-woodlands.Keywords: REDD+, greenhouse gases, biomass, tree mortality rate, timber logging rat

The Cryosphere Discussions

www.geosci-model-dev-discuss.net/6/3003/2013/ doi:10.5194/gmdd-6-3003-2013 © Author(s) 2013. CC Attribution 3.0 License

Point-of-Care Ultrasound for Tuberculosis Management in Sub-Saharan Africa-A Balanced SWOT Analysis.

Point-of-care ultrasound (POCUS) is an increasingly accessible skill, allowing for the decentralization of its use to non-specialist healthcare workers to guide routine clinical decision making. The advent of ultrasound-on-a-chip has transformed the technology into a portable mobile health device. Due to its high sensitivity to detect small consolidations, pleural effusions and sub pleural nodules, POCUS has recently been proposed as a sputum-free likely triage tool for tuberculosis (TB). To make an objective assessment of the potential and limitations of POCUS in routine TB management, we present a Strengths, Weaknesses, Opportunities &amp; Threats (SWOT) analysis based on a review of the relevant literature and focusing on Sub-Saharan Africa (SSA). We idenitified numerous strengths and opportunities of POCUS for TB management e.g.; accessible, affordable, easy to use &amp; maintain, expedited diagnosis, extra-pulmonary TB detection, safer pleural/pericardial puncture, use in children/pregnant women/PLHIV, targeted screening of TB contacts, monitoring TB sequelae, and creating AI decision support. Weaknesses and external threats such as operator dependency, lack of visualization of central lung pathology, poor specificity, lack of impact assessments and data from Sub-Saharan Africa must be taken into consideration to ensure that the potential of the technology can be fully realized in research as in practice

The potential of hyperspectral images and partial least square regression for predicting total carbon, total nitrogen and their isotope composition in forest litterfall samples

Hosseini Bai, S ORCiD: 0000-0001-8646-6423Purpose: The main objective of this study was to examine the potential of using hyperspectral image analysis for prediction of total carbon (TC), total nitrogen (TN) and their isotope composition (δ13C and δ15N) in forest leaf litterfall samples. Materials and methods: Hyperspectral images were captured from ground litterfall samples of a natural forest in the spectral range of 400–1700 nm. A partial least-square regression model (PLSR) was used to correlate the relative reflectance spectra with TC, TN, δ13C and δ15N in the litterfall samples. The most important wavelengths were selected using β coefficient, and the final models were developed using the most important wavelengths. The models were, then, tested using an external validation set. Results and discussion: The results showed that the data of TC and δ13C could not be fitted to the PLSR model, possibly due to small variations observed in the TC and δ13C data. The model, however, was fitted well to TN and δ15N. The cross-validation R2cv of the models for TN and δ15N were 0.74 and 0.67 with the RMSEcv of 0.53% and 1.07‰, respectively. The external validation R2ex of the prediction was 0.64 and 0.67, and the RMSEex was 0.53% and 1.19 ‰, for TN and δ15N, respectively. The ratio of performance to deviation (RPD) of the predictions was 1.48 and 1.53, respectively, for TN and δ15N, showing that the models were reliable for the prediction of TN and δ15N in new forest leaf litterfall samples. Conclusions: The PLSR model was not successful in predicting TC and δ13C in forest leaf litterfall samples using hyperspectral data. The predictions of TN and δ15N values in the external litterfall samples were reliable, and PLSR can be used for future prediction. © 2017, Springer-Verlag GmbH Germany