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Transdisciplinary development and adoption of irrigation innovations in Africa. Linkages to principles of CAADP: a commentary
No full textExpanding arable land under irrigation is cardinal in the quest to attain Africa's aspiration of transforming agriculture and realizing its true value and positive impact on wealth creation, economic growth, food security and nutrition for all. Over the last three to four decades, many initiatives have been designed to harness both small- and large-scale irrigation technologies towards increasing agricultural production and productivity. The EAU4Food (European Union and African Union cooperative research to increase food production in irrigated farming systems in Africa) project was a collaborative project under the EU–African Union Scientific Partnership aimed at enabling the successful adoption and upscaling of appropriate irrigation support innovations. The project applied a transdisciplinary approach to design, test and disseminate innovations across the continent. The project was designed to gain better insights vis-à-vis how the innovation process can be enhanced, and to share insights for supporting the implementation of national agricultural development programmes and strategies conceived within the context of the Comprehensive Africa Agriculture Development Programme (CAADP) framework. This note highlights linkages between the CAADP framework and the EAU4Food project and suggests some future areas of attention on Africa's agenda for enhanced agricultural production, facilitated under the auspices of CAADP.</p
Development and validation of a UHPLC-ESI-MS/MS method for quantification of oleandrin and other cardiac glycosides and evaluation of their levels in herbs and spices from the Belgian market
No full textCardiac glycosides (CGs) are naturally occurring plant secondary metabolites that can be toxic to humans and animals. The aim of this work was to develop a targeted analytical method utilizing liquid chromatography—tandem mass spectrometry (LC-MS/MS) for quantification of these plant toxins in a herbal-based food and human urine. The method included oleandrin, digoxin, digitoxin, convallatoxin, and ouabain. Samples of culinary herbs were extracted with acetonitrile and cleaned using Oasis® MAX solid-phase extraction (SPE), while samples of urine were diluted with acidified water and purified on Oasis® HLB SPE cartridges. Limits of quantification were in the range of 1.5–15 ng/g for herbs and 0.025–1 ng/mL for urine. The mean recovery of the method complied with the acceptable range of 70–120% for most CGs, and relative standard deviations were at maximum 14% and 19% for repeatability and reproducibility, respectively. Method linearity was good with calculated R2 values above 0.997. The expanded measurement uncertainty was estimated to be in the range of 7–37%. The LC-MS/MS method was used to examine 65 samples of culinary herbs and herb and spice mixtures collected in Belgium, from supermarkets and local stores. The samples were found to be free from the analyzed CGs.</p
Season-specific carryover of early life associations in a monogamous bird species
No full textSocial relationships can have important fitness consequences. Although there is increasing evidence that social relationships carry over across contexts, few studies have investigated whether relationships formed early in life are carried over to adulthood. For example, juveniles of monogamous species go through a major life history stage transition, pair formation, during which the pair bond becomes a central unit of the social organization. At present, it remains unclear whether pair members retain their early life relationships after pair formation. We investigated whether same-sex associations formed early in life carry over into adulthood and whether carryover was dependent on season, in a monogamous species. We also investigated the role of familiarity, genetic relatedness and aggression on the perseverance of social associations. We studied the social structure before and after pair formation in captive barnacle geese, Branta leucopsis, a highly social, long-lived, monogamous species. We constructed association networks of groups of geese before pair formation, during the subsequent breeding season and in the following wintering season. Next, we studied how these associations carried over during seasonal changes. We found that early life associations in females were lost during the breeding season but resurfaced during the subsequent wintering season. In males, the early life associations persisted across both seasons. Association persistence was not mediated by genetic relatedness or familiarity. The high level of aggressiveness of males, but not females, in the breeding season suggests that males may have played a key role in shaping both their own social environment and that of their partners. We show that early life social relationships can be maintained well into later life. Such relationships can be sustained even if they are temporarily disrupted, for example due to reproductive behaviour. Our findings therefore highlight that the early life social environment can have lifelong consequences for individuals’ social environment.</p
Effect of nitrogen, phosphorus and pH on biological wood oxidation at 42 °C
No full textBiological wood oxidation (BWO) is proposed as a cleaner alternative to wood combustion for heat production and wood waste management. Currently, BWO is not extensively studied and little is known about it. Nevertheless, given the composition of wood residues, which is dominated by carbon, nutrient availability may become a limiting factor during BWO. Our objective was to study the nutrition requirements for sustaining the BWO. For this purpose, three different factors including nitrogen addition, phosphorus addition and pH, were studied. Oxygen consumption and mass loss were monitored and used to evaluate the impact of nutrition on BWO and to calculate the theoretical heat production. The result showed that nitrogen addition at a relatively low level (2.5-10 mg/g) enhanced the cumulative oxygen consumption by 60–124% and mass loss by 28–95%, when compared with the BWO without nitrogen addition. The highest nitrogen addition examined in this research (20 mg/g), on the other hand, did not enhance BWO. Different phosphorus addition (0.5–5 mg/g) and pH (4–6) had little impacts on BWO. The highest theoretical heat production rate (0.63 W/kg dry wood biomass) was achieved using 2.5 mg/g nitrogen addition with a 95-day incubation. This suggests that nitrogen addition is required and able to sustain BWO. Besides, the cumulative oxygen consumption showed a good linear relationship with mass loss. This study provides the first indication on the effective quantify of nitrogen addition for enhancing BWO, which contributes to the selection of nutrient source for BWO in future studies.</p
Model-based evaluation of greenhouse microclimate using IoT-Sensor data fusion for energy efficient crop production
No full textEmission-free closed-field crop cultivation at a commercial scale necessitates microclimate evaluation for embracing the production uncertainties and maximizing the returns. This paper presents an application of the Internet-of-Things for model-based evaluation of microclimate parameters inside two greenhouse crop production systems. The objectives thus were to develop (i) a comfort ratio model, and (ii) a custom-built wireless sensor for data fusion in order to evaluate and compare microclimate parameters inside two different tropical greenhouses prior to the actual cultivation of tomato. The model was implemented in MATLAB Simulink with a flexible architecture and self-tuning reference inputs to work with different crops and cultural practices within which various growth stages can be modeled and analyzed. The accuracy and functional reliability of the sensor, as well as the performance of the model were validated by collecting and analyzing microclimate data from a naturally ventilated net-covered Screenhouse and a Polycarbonate Panel greenhouse under tropical lowland climate conditions of Malaysia. Raw data including air temperature, relative humidity, vapor pressure deficit and solar radiation were processed by the model for simulating comfort ratio values associated with different growth stages. Preliminary results showed that the mean and maximum vapor pressure deficit were respectively 1.19 and 5.1 kPa in the Polycarbonate Panel greenhouse and 0.97 and 3.81 kPa in the Screenhouse. Analyses based on comfort ratio values were validated with the results from raw data, showing that when temperature, relative humidity, and vapor pressure deficit were in the range of 25 ± 5 °C, 80 ± 20%, and 1.1±1 kPa in the Screenhouse, the comfort ratio values associated with the optimum reference borders were higher than those in the Polycarbonate Panel greenhouse. This study thus suggests that comfort ratio index is a more revealing indicator for comparing two or more greenhouses based on the dynamic assessment of microclimate parameters. The proposed method takes into an account the variation in each parameter, not only with the respect to different reference borders, but also by considering different time frames, light conditions and growth stages. The presented IoT sensor node and the Simulink model provide growers with a better insight into interpreting crop growth environment. The results of this study can contribute to optimal control strategies for a more efficient greenhouse crop production.</p
Theoretical risk of genetic reassortment should not impede development of live, attenuated Rift Valley fever (RVF) vaccines commentary on the draft WHO RVF Target Product Profile
No full textIn November 2019, The World Health Organization (WHO) issued a draft set of Target Product Profiles (TPPs) describing optimal and minimally acceptable targets for vaccines against Rift Valley fever (RVF), a Phlebovirus with a three segmented genome, in both humans and ruminants. The TPPs contained rigid requirements to protect against genomic reassortment of live, attenuated vaccines (LAVs) with wild-type RVF virus (RVFV), which place undue constraints on development and regulatory approval of LAVs. We review the current LAVs in use and in development, and conclude that there is no evidence that reassortment between LAVs and wild-type RVFV has occurred during field use, that such a reassortment event if it occurred would have no untoward consequence, and that the TPPs should be revised to provide a more balanced assessment of the benefits versus the theoretical risks of reassortment.</p
Analysis of highly polar pesticides and their main metabolites in animal origin matrices by hydrophilic interaction liquid chromatography and mass spectrometry
No full textIn this work, a method for the analysis of 14 highly polar pesticides in animal origin matrices by hydrophilic interaction liquid chromatography and mass spectrometry has been described. Three methanol-based extraction procedures with slight modifications, depending on the matrix, have been used. The method has been validated according to the performance criteria from the SANTE guideline for pesticide residues analysis in food and feed. Most of the compounds showed a limit of quantitation at the lowest spike levels tested (0.01–0.02 mg kg−1) in the matrices evaluated. A SPE clean-up step with mixed mode cation exchange sorbent has been used with some matrices, like chicken meat, eggs, liver and kidney, in order to improve the limits of quantification. Glufosinate, glyphosate and HEPA were the compounds which presented more difficulties during the study, due to the lack of sensitivity of the qualifier ions and/or because of the interference from the matrices.</p
Photosynthetic Acclimation to Fluctuating Irradiance in Plants
No full textUnlike the short-term responses of photosynthesis to fluctuating irradiance, the long-term response (i.e., acclimation) at the chloroplast, leaf, and plant level has received less attention so far. The ability of plants to acclimate to irradiance fluctuations and the speed at which this acclimation occurs are potential limitations to plant growth under field conditions, and therefore this process deserves closer study. In the first section of this review, we look at the sources of natural irradiance fluctuations, their effects on short-term photosynthesis, and the interaction of these effects with circadian rhythms. This is followed by an overview of the mechanisms that are involved in acclimation to fluctuating (or changes of) irradiance. We highlight the chain of events leading to acclimation: retrograde signaling, systemic acquired acclimation (SAA), gene transcription, and changes in protein abundance. We also review how fluctuating irradiance is applied in experiments and highlight the fact that they are significantly slower than natural fluctuations in the field, although the technology to achieve realistic fluctuations exists. Finally, we review published data on the effects of growing plants under fluctuating irradiance on different plant traits, across studies, spatial scales, and species. We show that, when plants are grown under fluctuating irradiance, the chlorophyll a/b ratio and plant biomass decrease, specific leaf area increases, and photosynthetic capacity as well as root/shoot ratio are, on average, unaffected.</p
Intra-catchment variability of surface saturation - Insights from physically based simulations in comparison with biweekly thermal infrared image observations
No full textIn this study, we explored the spatio-temporal variability of surface saturation within a forested headwater catchment using a combined simulation-observation approach. We simulated the occurrence of surface saturation in the Weierbach catchment (Luxembourg) with the physically based model HydroGeoSphere. We confronted the simulation with thermal infrared images that we acquired during a 2-year mapping campaign for seven distinct riparian areas with weekly to biweekly recurrence frequency. Observations and simulations showed similar saturation dynamics across the catchment. The observed and simulated relation of surface saturation to catchment discharge resembled a power law relationship for all investigated riparian areas but varied to a similar extent, as previously observed between catchments of different morphological and topographical characteristics. The observed spatial patterns and frequencies of surface saturation varied between and within the investigated areas and the model reproduced these spatial variations well. The good performance of the simulation suggested that surface saturation in the Weierbach catchment is largely controlled by exfiltration of groundwater into local topographic depressions. However, the simulated surface saturation contracted faster than observed, the simulated saturation dynamics were less variable between the investigated areas than observed, and the match of simulated and observed saturation patterns was not equally good in all investigated riparian areas. These mismatches between observations and simulation highlight that the intra-catchment variability of surface saturation must also result from factors that were not considered in the model set-up, such as differing subsurface structures or a differing persistence of surface saturation due to local morphological features like perennial springs.</p
Gut microbiota from persons with attention-deficit/hyperactivity disorder affects the brain in mice
No full textBackground: The impact of the gut microbiota on host physiology and behavior has been relatively well established. Whether changes in microbial composition affect brain structure and function is largely elusive, however. This is important as altered brain structure and function have been implicated in various neurodevelopmental disorders, like attention-deficit/hyperactivity disorder (ADHD). We hypothesized that gut microbiota of persons with and without ADHD, when transplanted into mice, would differentially modify brain function and/or structure. We investigated this by colonizing young, male, germ-free C57BL/6JOlaHsd mice with microbiota from individuals with and without ADHD. We generated and analyzed microbiome data, assessed brain structure and function by magnetic resonance imaging (MRI), and studied mouse behavior in a behavioral test battery. Results: Principal coordinate analysis showed a clear separation of fecal microbiota of mice colonized with ADHD and control microbiota. With diffusion tensor imaging, we observed a decreased structural integrity of both white and gray matter regions (i.e., internal capsule, hippocampus) in mice that were colonized with ADHD microbiota. We also found significant correlations between white matter integrity and the differentially expressed microbiota. Mice colonized with ADHD microbiota additionally showed decreased resting-state functional MRI-based connectivity between right motor and right visual cortices. These regions, as well as the hippocampus and internal capsule, have previously been reported to be altered in several neurodevelopmental disorders. Furthermore, we also show that mice colonized with ADHD microbiota were more anxious in the open-field test. Conclusions: Taken together, we demonstrate that altered microbial composition could be a driver of altered brain structure and function and concomitant changes in the animals' behavior. These findings may help to understand the mechanisms through which the gut microbiota contributes to the pathobiology of neurodevelopmental disorders. [MediaObject not available: See fulltext.]</p