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Towards a European Cal/Val service for earth observation
Get PDFSocietal dependence on, and commercial and scientific exploitation of Earth-Oriented remote sensing from satellites is growing at an exponential rate. The comprehensive EU Copernicus programme provides a major contribution to the global effort, but even so, to achieve the necessary global and temporal coverage requires synergistic cooperation and associated interoperability of the Worlds sensors. For a user to exploit Earth Observation (EO) data there must exist confidence in data characteristics, quality and reliable delivery. Although long-term data records for climate may be the most demanding in nature, generation of analysis-ready operational data sets for applications, as diverse as food security to pollution monitoring, all require the user to have some quantitative level of confidence in the data and derived information. A long-term Calibration/Validation (Cal/Val) vision necessitates clear ownership and long-term funding. Delineating the roles of the European Commission (EC), space agencies and member states in long-term Cal/Val would provide clarity. It is clear that the space agencies have the responsibility to meet the mission requirement of their spaceborne instruments but long-term validation is often entrusted to interested parties bringing their own resources to the task. Furthermore, there is a critical need for Fiducial Reference Measurements (FRMs), acquired in operational mode, and comprehensive in coverage both spatially and temporally, to assure that the satellite product accuracies are met. This paper discusses the current status, gaps and challenges regarding long-term Cal/Val of EO satellites and recommends the creation of a European coordinating entity for satellite product calibration and validation. The proposed entity would be an integrative organization coordinating the European Cal/Val activities in partnership with the member states and the space agencies and working together with existing data providers to secure access to satellite and in-situ data of traceable FRM standards.</p
BENEFIT Partnership - 2019 annual report : Bilateral Ethiopian-Netherlands effort for food, income and trade partnership
Get PDFLimited mass-independent individual variation in resting metabolic rate in a wild population of snow voles (Chionomys nivalis)
No full textResting metabolic rate (RMR) is a potentially important axis of physiological adaptation to the thermal environment. However, our understanding of the causes and consequences of individual variation in RMR in the wild is hampered by a lack of data, as well as analytical challenges. RMR measurements in the wild are generally characterized by large measurement errors and a strong dependency on mass. The latter is problematic when assessing the ability of RMR to evolve independently of mass. Mixed models provide a powerful and flexible tool to tackle these challenges, but they have rarely been used to estimate repeatability of mass-independent RMR from field data. We used respirometry to obtain repeated measurements of RMR in a long-term study population of snow voles (Chionomys nivalis) inhabiting an environment subject to large circadian and seasonal fluctuations in temperature. Using both uni- and bivariate mixed models, we quantify individual repeatability in RMR and decompose repeatability into mass-dependent and mass-independent components, while accounting for measurement error. RMR varies among individuals, that is, is repeatable (R =.46) and strongly co-varies with BM. Indeed, much of the repeatability of RMR is attributable to individual variation in BM, and the repeatability of mass-independent RMR is reduced by 41% to R =.27. These empirical results suggest that the evolutionary potential of RMR independent of mass may be severely constrained. This study illustrates how to leverage bivariate mixed models to model field data for metabolic traits, correct for measurement error and decompose the relative importance of mass-dependent and mass-independent physiological variation.</p
The potential of highly nutritious frozen stages of Tyrophagus putrescentiae as a supplemental food source for the predatory mite Amblyseius swirskii
Get PDFAstigmatid mites have potential as supplementary prey items to support generalist predator populations in crops. However, applying living prey mites has some disadvantages; if not predated they have the potential to cause crop damage and allergies. In this study, we evaluated various diets based on the astigmatid mite Tyrophagous putrescentiae (Schrank) as a supplemental food source for the predatory mite Amblyseius swirskii Ahias-Henriot. Eggs and larvae of T. putrescentiae were reared on a diet of dog food (rich in proteins and fat) or bran (rich in carbohydrate); they were offered either frozen or alive, and either with or without cattail pollen (Typha angustifolia L.). Oviposition rate of A. swirskii fed with frozen mite larvae reared on dog food was similar to the rate observed when they were fed with cattail pollen or living prey mites, but developmental time of A. swirskii was longer on this frozen diet than on a diet of living prey mites or pollen. Both living and frozen prey mites were, in contrast with cattail pollen, not suitable for oviposition by western flower thrips, Frankliniella occidentalis Pergande. In a greenhouse study, the use of frozen prey mite stages as supplemental food on chrysanthemum plants allowed populations of A. swirskii to establish, but not increase; in contrast, provision of living prey mites and pollen increased A. swirskii populations on plants. Hence, our study shows that living prey mites, but not frozen prey mites, had the greatest potential as a supplemental food source for A. swirskii.</p
The MCRA toolbox of models and data to support chemical mixture risk assessment
Get PDFA model and data toolbox is presented to assess risks from combined exposure to multiple chemicals using probabilistic methods. The Monte Carlo Risk Assessment (MCRA) toolbox, also known as the EuroMix toolbox, has more than 40 modules addressing all areas of risk assessment, and includes a data repository with data collected in the EuroMix project. This paper gives an introduction to the toolbox and illustrates its use with examples from the EuroMix project. The toolbox can be used for hazard identification, hazard characterisation, exposure assessment and risk characterisation. Examples for hazard identification are selection of substances relevant for a specific adverse outcome based on adverse outcome pathways and QSAR models. Examples for hazard characterisation are calculation of benchmark doses and relative potency factors with uncertainty from dose response data, and use of kinetic models to perform in vitro to in vivo extrapolation. Examples for exposure assessment are assessing cumulative exposure at external or internal level, where the latter option is needed when dietary and non-dietary routes have to be aggregated. Finally, risk characterisation is illustrated by calculation and display of the margin of exposure for single substances and for the cumulation, including uncertainties derived from exposure and hazard characterisation estimates.</p
A systematic review of factors influencing spatiotemporal variability in urban water and energy consumption
Get PDFUnderstanding which factors influence urban metabolism is a prerequisite for designing policies and plans that effectuate sustainable resource management. A growing number of publications is concerned with these factors. Yet, this emerging field of research lacks a common framework that supports researchers in interpreting their findings, such as generalizability to other cities, and making informed decisions on their research design. Aiming to contribute to building such a framework, we systematically reviewed urban metabolism literature. This review paper presents an overview of factors influencing urban water and energy consumption and their effect on consumption, and it describes the interconnectedness of these factors for six different types of relationships. Results disclose fourteen drivers, changes in societal context that shape consumption patterns, and twenty-one facilitators/constraints. The latter type of factors include consumer, resource and urban landscape characteristics that affect resource consumption by facilitating or constraining specific activities. Findings indicate commonalities between primary studies in terms of prevalent observed effect direction for a given factor. However, the interconnections between different factors can influence the direction and magnitude of effects and thereby result in case-specific variability in consumption patterns. Future research should enhance the understanding of these interconnections, strengthen the evidence for the factors presented here and provide insight in additional factors of influence. It is essential to align these studies in terms of a common terminology, transparent quality assessment and a unified approach to measuring and expressing factors of influence. Connecting with related disciplines working on a common systems approach is key to realize the full potential of urban metabolism research to advance our understanding of cities.</p
The Rural Household Multiple Indicator Survey, data from 13,310 farm households in 21 countries
Get PDFThe Rural Household Multiple Indicator Survey (RHoMIS) is a standardized farm household survey approach which collects information on 758 variables covering household demographics, farm area, crops grown and their production, livestock holdings and their production, agricultural product use and variables underlying standard socio-economic and food security indicators such as the Probability of Poverty Index, the Household Food Insecurity Access Scale, and household dietary diversity. These variables are used to quantify more than 40 different indicators on farm and household characteristics, welfare, productivity, and economic performance. Between 2015 and the beginning of 2018, the survey instrument was applied in 21 countries in Central America, sub-Saharan Africa and Asia. The data presented here include the raw survey response data, the indicator calculation code, and the resulting indicator values. These data can be used to quantify on- and off-farm pathways to food security, diverse diets, and changes in poverty for rural smallholder farm households.</p
The thermophilic route to succinic acid
Get PDFPseudoclostridium thermosuccinogenes is the only known thermophile that produces succinic acid as one of its main fermentations products, together with acetic acid and formic acid, as well as ethanol, lactic acid, and hydrogen in smaller quantities. Thermophilic cell-factories, and succinic acid are both of interest for industrial biotechnology, and it is therefore that we set out to try to understand the metabolism of P. thermosuccinogenes. In Chapter 2 we published the genome sequences of the four available P. thermosuccinogenes strains (at that point still called Clostridium thermosuccinogenes). The genome of the type strain (DSM 5807) was fully closed. Using these annotated genomes, we were able to reconstruct its central metabolism. The genes for the pathways towards all the fermentation products were identified, as well as the complete Embden-Meyerhof-Parnas pathway. All genes for the pentose phosphate pathway (including those for xylose assimilation) were identified except for a transaldolase. Transcriptomics during growth on xylose versus glucose did not provide any leads to potential transaldolase genes or alternatives. Enzyme assays with cell-free extract were conducted to study cofactor usage of various glycolytic reactions. We were able to show that glucokinase was GTP-dependent and that 6-phosphofructokinase was PPi-dependent, verifying what was previously shown in Hungateiclostridium thermocellum, a close relative of P. thermosuccinogenes. Furthermore, xylulokinase was shown to use GTP as well. In Chapter 3 we looked further at the cofactor usage of P. thermosuccinogenes. Thirteen genes were cloned and heterologously expressed in Escherichia coli (encoding ribokinase, galactokinase, acetate kinase, isocitrate dehydrogenase, three 6-phosphofructokinase (PFK) orthologs, three glyceraldehyde 3-phosphate dehydrogenase (GAPDH) orthologs, and three genes encoding either pyruvate kinase, pyruvate, phosphate dikinase, or phosphoenolpyruvate synthase). Via enzyme assays we showed that besides glucokinase and xylulokinase, galactokinase and ribokinase are also GTP-dependent, suggesting that sugar phosphorylation by and large is GTP-dependent in P. thermosuccinogenes. Of the three PFKs, we confirmed which was PPi-dependent, and we found that another was active with both ATP and GTP; no activity was found for the third. Two GAPDHs were found to be NAD+-dependent. Further, the use of PPi and GTP as phosphoryl carriers was extensively discussed; we hypothesize that the use of GTP allows for different (or more flexible) reaction thermodynamics compared to reactions relying on ATP. In Chapter 4 the pathway to succinic acid in P. thermosuccinogenes was investigated in more detail. The fumarate hydratase and fumarate reductase (FRD) genes reside in an operon together with the genes for a large electron bifurcating NADH-reductase-heterodisulfide reductase complex (Flx-Hdr) that takes electrons from NADH, reducing ferredoxin and a disulfide bond simultaneously. The FRD differs significantly from studied isoforms, but is closest related to methanogenic FRDs that use thiols to reduce fumarate. Based on this genomic context and comparative genomics, we propose two hypothetical mechanisms through which the FRD associates with the electron bifurcating Flx-Hdr complex: (1) A disulfide bond from a hitherto unknown cofactor is reduced by the Flx-Hdr complex, using NADH to generate two thiol groups, while facilitating the unfavourable reduction of ferredoxin by NADH. The disulfide bond is subsequently regenerated via the reduction of fumarate to succinate by the FRD using the previously formed thiol groups. Or, (2) the FRD forms an integral part of the FlxABCD-HdrABC complex, and NADH is used to reduce ferredoxin and fumarate directly, without an intermediate disulfide-forming cofactor. Either way enables the conservation of additional energy (in the form of reduced ferredoxin) by a soluble FRD. Some preliminary, inconclusive experimental data are presented as well. In Chapter 5 the effect of CO2 limitation on succinate yield and on the metabolism of P. thermosuccinogenes in general was studied. Succinate production is connected to net fixation of CO2 (by PEP carboxykinase) and was, therefore, expected to be impacted significantly. Batch cultivations in bioreactors sparged with 1% and 20% CO2 were conducted that allowed us to carefully study the effect of CO2 limitation. Formate yield was greatly reduced at low CO2 concentrations, signifying a switch from pyruvate formate lyase (PFL) to pyruvate:ferredoxin oxidoreductase (PFOR) for acetyl-CoA formation. The corresponding increase in endogenous CO2 production (by PFOR) enabled succinic acid production to be largely maintained as its yield was reduced by only 26%. Acetate yield was slightly reduced as well, while that of lactate was slightly increased. CO2 limitation also prompted the formation of significant amounts of ethanol, which is only marginally produced during CO2 excess. Altogether, the changes in fermentation product yields result in increased ferredoxin and NAD+ reduction, and increased NADPH oxidation during CO2 limitation, which must be linked to reshuffled (trans)hydrogenation mechanisms of those cofactors, to keep them balanced. RNA sequencing, to investigate transcriptional effects of CO2 limitation, yielded only ambiguous results regarding the known (trans)hydrogenation mechanisms, hinting at a decreased NAD+/NADH ratio, which could ultimately be responsible for the stress observed during CO2 limitation. Clear overexpression of an alcohol dehydrogenase (adhE) was observed, which explains the increased ethanol production, while no changes were seen for PFL and PFOR expression that could explain the anticipated switch based on the fermentation results. In Chapter 6 the pentose phosphate pathway of Hungateiclostridiaceae was investigated to find out how they are able to interconvert C5 and C3/C6 metabolites in the absence of a transaldolase. We were able to confirm that Hungateiclostridiaceae rely on the sedoheptulose 1,7-bisphosphate (SBP) pathway, using pyrophosphate-dependent phosphofructokinase (PPi-PFK) instead of transaldolase. In the SBP pathway, sedoheptulose 7-phosphate is converted to SBP by PPi-PFK after which fructose bisphosphate aldolase cleaves SBP into dihydroxyacetone phosphate and erythrose 4-phosphate. We showed that PPi-PFK of P. thermosuccinogenes and of H. thermocellum indeed can convert S7P to SBP, and that they have similar affinities for S7P and fructose 6-phosphate (F6P), the canonical substrate. By contrast, (ATP-dependent) PfkA of Escherichia coli (which does rely on transaldolase) has a very poor affinity for S7P, indicative of the fact that the PPi-PFK of the Hungateiclostridiaceae has evolved for the use of S7P. We further show that P. thermosuccinogenes contains a significant SBP pool, an otherwise unusual metabolite, which is elevated during growth on xylose, demonstrating its relevance for pentose assimilation
The butterflies of St. Eustatius with faunal comparisons among the adjacent islands of the Lesser Antilles
No full textBased on four years of butterfly monitoring in four contrasting natural habitats on St. Eustatius, we document large and consistent differences in the butterfly species assemblages in the different habitats and compare the butterfly assemblages of the three windward Dutch islands to those of other islands of the Lesser Antilles. Seven new species records were established for St. Eustatius, thereby updating the butterfly list to a total of 32 species. Pieridae were the most numerically abundant group of butterflies (48%), followed by Lycaenidae (26%), Hesperiidae (12%), and smaller numbers of both Heliconiinae (6%) and Charaxinae (5%). Heliconiinae and Charaxinae both showed a significant dependence on the moister, wind-sheltered habitats of the volcanic slopes and crater of the Quill, but this dependence was particularly strong for Heliconiinae. The butterfly faunas of the windward Dutch islands numbered a total of 44 species. The presence of larval host plants needed for local reproduction was confirmed for all but two species. Cluster analysis separated the butterfly faunas of these and the surrounding islands into two groups. The more speciose butterfly assemblages of Saba, St. Eustatius, and St. Martin clustered together with the those of the surrounding higher islands of Antigua, Montserrat, Nevis, and St. Kitts, while the poorer faunas of the low-lying islands of Anguilla, St. Bartholomew, and Barbuda formed a separate cluster and had a lower species richness particularly in the Heliconiinae and Charaxinae. Based on consistent effects of elevation on butterfly faunas, at both geographic scales (between areas on St. Eustatius and between islands), our results suggest that island maximum elevation is the overriding factor explaining the distribution of butterfly faunal richness in the northern Lesser Antillean islands studied