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Precipitation-fire-functional interactions control biomass stocks and carbon exchanges across the world’s largest savanna
Get PDFSouthern African woodlands (SAW) are the world's largest savanna, covering ∼ 3 M km2, but their carbon balance and its interactions with climate and disturbance are poorly understood. Here we address three issues that hinder regional efforts to address international climate agreements: producing a state-of-the-art C budget of the SAW region; diagnosing C cycle functional variation and interactions with climate and fire across SAW; and evaluating SAW C cycle representation in land surface models (LSMs). Using 1506 independent 0.5° pixel model calibrations, each constrained with local Earth observation time series of woody carbon stocks (Cwood) and leaf area, we produce a regional SAW C analysis (2006–2017). The regional net biome production is neutral, i.e. −0.08 Mg C ha−1 yr−1 (95 % uncertainty interval −1.67/1.66), with fire emissions contributing ∼ 0.88 Mg C ha−1 yr−1 (95 % uncertainty interval 0.36–2.51). Fire-related mortality driving fluxes from the total Cwood to dead organic matter likely exceeds both fire-related emissions from Cwood into the atmosphere and non-fire Cwood mortality. The emergent spatial variation in biogenic fluxes and C pools is strongly correlated with mean annual precipitation and burned area. However, there are multiple, potentially confounding, causal pathways through which variation in environmental drivers impacts the spatial distribution of C stocks and fluxes, which is mediated by spatial variations in functional parameters like allocation, wood lifespan, and fire resilience. More Cwood in wetter areas is caused by positive precipitation effects on net primary production and on parameters for wood lifespan but is damped by a negative effect with rising precipitation increasing fire-related mortality. Compared to this analysis, LSMs showed marked differences in spatial distributions and magnitudes of C stocks and fire emissions. The current generation of LSMs represents savanna as a single plant functional type, missing important spatial functional variations identified here. Patterns of biomass and C cycling across the region are the outcome of climate controls on production and vegetation–fire interactions which determine residence times, which is linked to spatial variations in key ecosystem functional characteristics
Revision of the CNO cycle: Rate of 17O destruction in stars
No full textBackground: The CNO cycle powers core H burning, in stars with >1.2⊙, and shell H burning, during the advanced evolutionary phases. Therefore, the uncertainties affecting the reaction rates of proton captures on C, N, and O isotopes limit our understanding of stellar evolution and nucleosynthesis.Purpose: We aim to develop a general and self-consistent tool for the calculation of nuclear reaction rates and their uncertainties, starting from available experimental data. As a longer term plan, we intend to use this tool to revise the proton-capture reactions of the CNO cycle for which new experimental data are or will be available in the next future.Method: The general procedure consists of -matrix cross section calculations based on available measurements of the relevant nuclear parameters (energies, widths, strengths of known resonances, interference patterns, etc.), coupled to a Monte Carlo procedure to evaluate the global reaction rate error.Results: A first application of this method to 17O(,)18F and 17O(,)14N, the reactions that determine the 17O destruction in stellar interiors where the CNO cycle is active, is presented. These two reactions also allow us to test the multichannel and multilevel capabilities of the -matrix method. In the temperature range of hydrostatic H burning (<100 MK), we confirm that the median rates are up to a factor of 2 higher than those suggested in reaction rate libraries commonly used in stellar model calculations. In this temperature range, the 17O destruction mainly proceeds through the 17O(,)14N channel, whose rate is known within ±20% (95% C.L.).Conclusions: Based on current stellar models of red giant stars, we show that this uncertainty produces a 10% variation on the predicted 16O/17O abundance ratio. Other uncertainties, such as those affecting the 17O production rate, i.e., the 16O(,)17F reaction, have a stronger impact on this theoretical prediction, a fact that motivates further experimental investigations of the 17O production channel
Mentorship model for veterinary paraprofessionals
No full textThrough an innovative continuous professional development training programme, “Growing your business through preventive livestock healthcare”, the Food and Agriculture Organization of the United Nations (FAO) has aimed to address private sector veterinary paraprofessionals’ skills gaps and support them to develop successful businesses providing preventive livestock health services to small-scale farmers and pastoralists. These training courses were piloted in Nigeria, South Africa and Uganda in 2023. This document will outline the mentoring scheme that was part of the programme and some of the main lessons learned from the experience in Uganda and Nigeria
Meta-analysis of genome-wide associations and polygenic risk prediction for atrial fibrillation in more than 180,000 cases
No full textAtrial fibrillation (AF) is the most common heart rhythm abnormalityand is a leading cause of heart failure and stroke. This large-scalemeta-analysis of genome-wide association studies increased the powerto detect single-nucleotide variant associations and found more than 350AF-associated genetic loci. We identified candidate genes related to musclecontractility, cardiac muscle development and cell–cell communicationat 139 loci.Chromatin accessibility was assessed using assayfor transposase-accessible chromatin with sequencing and histone H3lysine 4 trimethylation in stem cell-derived atrial cardiomyocytes. A marked increase in chromatin accessibility for our sentinel variants and prioritized genes in atrial cardiomyocytes was observed. A polygenic risk score (PRS) based on the updated effect estimates in this improved AF risk prediction compared with previous risk estimates.<br/
Active prevention and treatment of post-critical illness anemia – is it time for large effectiveness trials
No full textCas10 based 7SL-sRNA diagnostic for the detection of active trypanosomosis
No full textAnimal Trypanosomosis (AT) is a significant disease affecting cattle across sub-Saharan Africa, Latin America, and Asia, posing a major threat to economic productivity and animal welfare. The absence of reliable diagnostic tests has led to an over-reliance on widespread pre-emptive drug treatments, which not only compromise animal health but also heighten the risk of drug resistance. The chronic nature of AT, characterized by cyclical low or undetectable parasite levels, and the necessity for field-applicable tests that can distinguish between active infection and prior exposure, present considerable challenges in developing effective diagnostics. In previous work, we identified a parasite-specific small RNA, 7SL-sRNA, which is detectable in the serum of infected cattle, even during the chronic stages of infection. However, existing methods for detecting sRNA require specialized equipment, making them unsuitable for field use. In this study, we have developed both a fluorescence-based and a lateral flow diagnostic test utilizing Cas10 technology for the detection of 7SL-sRNA from Trypanosoma congolense and Trypanosoma brucei. The fluorescence assay detects 10 – 100 fM T. congolense 7SL-sRNA and 1 pM T. brucei 7SL-sRNA, and the lateral flow assay showed a limit of detection of 1 – 10 pM for both species. Either assay can effectively identify active infections in cattle, including during chronic phases (with positive signals observed up to the experimental end point, 63 days post infection). This also highlights the effective use of Cas10 for small RNA detection, paving the way for a cost-effective, user-friendly, and field-deployable diagnostic test for AT, while establishing Cas10 technology for the detection of small RNAs in general.</p
Activation of Wnt/β-catenin signalling by mutually exclusive FBXW11 and CTNNB1 hotspot mutations drives salivary gland basal cell adenoma.
No full textBasal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) of the salivary gland are rare tumours that can be difficult to distinguish from each other and other salivary gland tumour subtypes. Using next-generation sequencing, we identify a recurrent FBXW11 missense mutation (p.F517S) in BCA that is mutually exclusive with the previously reported CTNNB1 p.I35T gain-of-function (GoF) mutation with these mutations collectively accounting for 94% of BCAs. In vitro, mutant FBXW11 is characterised by defective binding to β-catenin and higher protein levels within the nucleus. This is consistent with the increased nuclear expression of β-catenin and activation of the Wnt/β-catenin pathway. The genomic profiles of BCAC are distinct from BCA, with hotspot DICER1 and HRAS mutations and putative driver mutations affecting PI3K/AKT and NF-κB signalling pathway genes. These findings have important implications for the diagnosis and treatment of BCA and BCAC, which, despite histopathologic overlap, may be unrelated entities.</p
Regulating the very Limited Partnership
No full textLimited partnerships (LPs) have received considerable press and policy attention over the past five years, culminating in legal reforms which provide an ability to align LP law more closely to company law. This article challenges the wisdom of exercising this ability without prior analysis. It draws on historical, conceptual, and empirical methodologies to make three arguments. First, the LP is conceptually different from the company, with LPs being a legal transplant copied from global legal forms, and remaining distinctive: with (mostly) one manager which is meant to have unlimited liability. Second, LPs have clear policy aims which are different to those in company law. I use limited liability of an illustration of a policy point that will be missed by aligning LP law to company law. Third, the LP is overwhelmingly a Scottish vehicle. Recent company law reforms have been argued to be dissonant to Scottish company law, questioning the wisdom of aligning the limited partnership’s regulation to companies
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