2,466 research outputs found

    Groundwater use for irrigation - a global inventory

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    Irrigation is the most important water use sector accounting for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. While the extent of irrigation and related water uses are reported in statistical databases or estimated by model simulations, information on the source of irrigation water is scarce and very scattered. Here we present a new global inventory on the extent of areas irrigated with groundwater, surface water or non-conventional sources, and we determine the related consumptive water uses. The inventory provides data for 15 038 national and sub-national administrative units. Irrigated area was provided by census-based statistics from international and national organizations. A global model was then applied to simulate consumptive water uses for irrigation by water source. Globally, area equipped for irrigation is currently about 301 million ha of which 38% are equipped for irrigation with groundwater. Total consumptive groundwater use for irrigation is estimated as 545 km3 yr−1, or 43% of the total consumptive irrigation water use of 1 277 km3 yr−1. The countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the United States of America (17 million ha). Groundwater use in irrigation is increasing both in absolute terms and in percentage of total irrigation, leading in places to concentrations of users exploiting groundwater storage at rates above groundwater recharge. Despite the uncertainties associated with statistical data available to track patterns and growth of groundwater use for irrigation, the inventory presented here is a major step towards a more informed assessment of agricultural water use and its consequences for the global water cycle

    Design of biochemical pattern forming systems from minimal motifs

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    Although molecular self-organization and pattern formation are key features of life, only very few pattern-forming biochemical systems have been identified that can be reconstituted and studied in vitro under defined conditions. A systematic understanding of the underlying mechanisms is often hampered by multiple interactions, conformational flexibility and other complex features of the pattern forming proteins. Because of its compositional simplicity of only two proteins and a membrane, the MinDE system from Escherichia coli has in the past years been invaluable for deciphering the mechanisms of spatiotemporal self-organization in cells. Here, we explored the potential of reducing the complexity of this system even further, by identifying key functional motifs in the effector MinE that could be used to design pattern formation from scratch. In a combined approach of experiment and quantitative modeling, we show that starting from a minimal MinE-MinD interaction motif, pattern formation can be obtained by adding either dimerization or membrane-binding motifs. Moreover, we show that the pathways underlying pattern formation are recruitment-driven cytosolic cycling of MinE and recombination of membrane-bound MinE, and that these differ in their in vivo phenomenology

    Antibiotic Resistance and Substrate Utilization by Bacteria Affi liated with Cave Streams at Diff erent Levels of Mammoth Cave

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    Located in south-central Kentucky, Mammoth Cave is one of the most unique National Parks in the United States. The surface landscape includes complex relationships between the flora and fauna along with human influences. However, the primary ecological focus is concealed below ground. Over four-hundred miles of cave passages, created by fl owing groundwater over millions of years, host a variety of macro and micro organisms. The Green River has cut into the limestone formation over geologic time, creating a complex network of passages that are stacked, one below the other, with the newer levels of cave lying near the bottom. Palmer (2007, 1987) describes 4 main levels of cave passages in the Mammoth Cave system. A detailed discussion of the geology and conditions that formed the cave levels can be found in several reports (Palmer, 1987; Palmer 1989; White and White, 1989; Granger, et al, 2001). Precipitation continues to provide water that traverses from the surface, through the unsaturated vadose levels of the cave, and down to the water table in the lower level. Water enters the cave system through direct recharge at sinkholes and through diff use percolation. The rapid infiltration of stormwater often exceeds the carrying capacity of the upper cave passages and excess water is pushed into void pore-spaces near the top of bedrock. This stored water is slowly released and provides base-fl ow to cave streams that replenish the pools and streams in the lowest level of the cave (Ryan and Meimen, 1996). These perennial cave streams carry many of the organic compounds that provide energy to the cave ecosystem (Barr, 1976)

    Inkomenseffecten van de GLB-aanpassingen per 2020 : een quick scan

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    Minister Schouten heeft in mei 2019 vier scenario’s geschetst voor de nationale invulling van het Gemeenschappelijke Landbouwbeleid (GLB) na 2020. Kamerlid Bisschop heeft gevraagd om een vijfde scenario op te stellen, en de gevolgen van de verschillende scenario’s voor het inkomen uit bedrijf en de economische vitaliteit van landbouwbedrijven in kaart te laten brengen. Dit rapport geeft een doorrekening op hoofdlijnen van de scenario’s voor het inkomen uit bedrijf en een analyse van de gevolgen voor de economische vitaliteit van landbouwbedrijven. De laatste is mede gebaseerd op een analyse van de wijze waarop bedrijven in de huidige implementatieperiode van het GLB (2014-2020) zijn omgegaan met veranderingen in de toeslagen

    Anionic Magnesium and Calcium Hydrides : Transforming CO into Unsaturated Disilyl Ethers

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    OA-artikkeli, mutta ladattaessa tulee hieman erinäköinen versio (esim. ei lisenssiä). Tallennettu kuitenkin OA-artikkelina.The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be “terminal”, but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.Peer reviewe

    A harmonized method for automatable life cycle sustainability performance assessment and comparison of civil engineering works design concepts

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    The life cycle sustainability performance of civil engineering works is increasingly important. The possibility to influence the sustainability of a project design is larger in the conceptual stage than in later stages. Better-informed decisions regarding design choices’ impact on sustainability can be made by comparing conceptual project designs based on an assessment of their life cycle sustainability performance. It is essential that concepts are assessed in a harmonized way and compared impartially. Current standards provide the general framework for the assessment of sustainability performance, but do not give detailed guidance on calculation of sustainability indicators and their aggregation. Since design in automated systems is becoming increasingly common, there is a growing need for machine-readable data and automatable assessment methods. Assessment methods which can be applied using open-access data is important to achieve fair competition. This paper aims to provide a method for life cycle sustainability performance assessment and comparison of civil engineering works design concepts, possible to apply using open-access Environmental Product Declarations (EPDs) and life cycle assessment (LCA) data. The purpose is to enable fair and automatable sustainability assessments of design concepts, to facilitate impartial comparisons of such assessments as a basis for choosing sustainable designs. A literature review of relevant standards and scientific papers on sustainability assessment of construction and civil engineering works was performed. A harmonized, fair and automatable method for life cycle sustainability assessment and comparison of civil engineering works design concepts, well-suited for optimization purposes, is presented. However, the aim currently limits categories and indicators possible to include. The proposed method includes guidance on the calculation of environmental, social and economic indicators, based on LCA, life cycle costing (LCC) and external costs, and aggregation using normalisation and weighting factors of the Product Environmental Footprint (PEF). The proposed method allows for an impartial comparison of the sustainability of design concepts, resulting in better-informed decisions

    Entwicklung von Wertschöpfungsketten für Körnererbsen und Ackerbohnen: Fördernde und hemmende Faktoren

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    Das Demonstrationsnetzwerk DemoNetErBo hat zum Ziel, den Anbau und die Verwertung von Körnererbsen und Ackerbohnen in Deutschland nachhaltig zu steigern und zu verbessern. Dazu werden Wertschöpfungsketten für regional erzeugte Hülsenfrüchte entwickelt und optimiert, wofür die Kenntnis sogenannter kritischer Erfolgsfaktoren, die diesen Prozess von Anbau über Verarbeitung bis hin zur Vermarktung hemmen oder fördern, unerlässlich ist. Beispielhaft wird die unterschiedliche Situation in ökologischen und konventionellen Wertschöpfungsketten betrachtet
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