Simulating solute transport in an aggregated soil with the dual-porosity model: measured and optimized parameter values

The capability of the first-order, dual-porosity model, which explicitly accounts for non-ideal transport caused by the presence of ‘immobile’ water, to predict the non-ideal transport of non-sorbing solute in a constructed aggregated soil has been investigated. Miscible-displacement experiments performed with a well-characterized aggregated soil and a non-reactive tracer (pentafluorobenzoate) served as the source of the data. Values for the input parameters associated with physical non-equilibrium were determined independently and compared with values obtained by curve fitting of the experimental measurements. The calculated and optimized values compared well, suggesting that the non-equilibrium parameters represent actual physical phenomen

A robust circadian rhythm of metabolites in Arabidopsis thaliana mutants with enhanced growth characteristics

Solid state NMR/Biophysical Organic Chemistr

Coping with Uncertainty in River Management:Challenges and Ways Forward

Coping with uncertainties is inherent to river management planning and policymaking. Yet, policymakers often perceive uncertainty as a complicating factor. We examine the challenges faced by policymakers when coping with uncertainties and provide an action perspective on how to best cope with these challenges to inform the policy debate. Integrating social and natural scientist’s perspectives on uncertainties and learning theories, we present a holistic, management perspective for coping with uncertainty. Based on a literature review about uncertainty concepts, strategies and learning, we identify three challenges in current river management: balancing social and technical uncertainties, being conservative and avoiding to end up a lock-in situation. We then provide a step-wise strategy and concrete actions for policymakers, which are illustrated with several examples. We conclude that coping with uncertainty may require paradigm shifts that can only be achieved through organisational learning. This, we claim, requires reflection, learning and flexibility of policymakers and their organisation

Enhancement of Arabidopsis growth characteristics using genome interrogation with artificial transcription factors

Plant science

Plasmodium Cysteine Repeat Modular Proteins 3 and 4 are essential for malaria parasite transmission from the mosquito to the host

Background: The Plasmodium Cysteine Repeat Modular Proteins (PCRMP) are a family of four conserved proteins of malaria parasites, that contain a number of motifs implicated in host-parasite interactions. Analysis of mutants of the rodent parasite Plasmodium berghei lacking expression of PCRMP1 or 2 showed that these proteins are essential for targeting of P. berghei sporozoites to the mosquito salivary gland and, hence, for transmission from the mosquito to the mouse. Methods: In this work, the role of the remaining PCRMP family members, PCRMP3 and 4, has been investigated throughout the Plasmodium life cycle by generation and analysis of P. berghei gene deletion mutants,.pcrmp3 and.pcrmp4. The role of PCRMP members during the transmission and hepatic stages of the Plasmodium lifecycle has been evaluated by light- and electron microscopy and by analysis of liver stage development in HEPG2 cells in vitro and by infecting mice with mutant sporozoites. In addition, mice were immunized with live Delta pcrmp3 and Delta pcrmp4 sporozoites to evaluate their immunization potential as a genetically-attenuated parasite-based vaccine. Results: Disruption of pcrmp3 and pcrmp4 in P. berghei revealed that they are also essential for transmission of the parasite through the mosquito vector, although acting in a distinct way to pbcrmp1 and 2. Mutants lacking expression of PCRMP3 or PCRMP4 show normal blood stage development and oocyst formation in the mosquito and develop into morphologically normal sporozoites, but these have a defect in egress from oocysts and do not enter the salivary glands. Sporozoites extracted from oocysts perform gliding motility and invade and infect hepatocytes but do not undergo further development and proliferation. Furthermore, the study shows that immunization with Delta crmp3 and Delta crmp4 sporozoites does not confer protective immunity upon subsequent challenge. Conclusions: PCRMP3 and 4 play multiple roles during the Plasmodium life cycle; they are essential for the establishment of sporozoite infection in the mosquito salivary gland, and subsequently for development in hepatocytes. However, although Delta pcrmp3 and Delta pcrmp4 parasites are completely growth-impaired in the liver, immunization with live sporozoites does not induce the protective immune responses that have been shown for other genetically-attenuated parasites.Host-parasite interactio

An Arabidopsis mutant with high operating efficiency of Photosystem II and low chlorophyll fluorescence

Plant science

Bodemvocht uit satellietdata: wat kan de Nederlandse waterbeheerder ermee?

Het onderzoeksproject ‘Optimizing Water Availability with Sentinel-1 Satellites’ heeft als doel te onderzoeken hoe satellietdata gebruikt kan worden in het Nederlandse waterbeheer. Het onderzoek laat zien dat de satelliet Sentinel-1 buiten het groeiseizoen om al een vrij goed beeld geeft van het bodemvochtgehalte. Hiermee kan bijvoorbeeld de berijdbaarheid van landbouwpercelen in kaart gebracht kan worden. Ook is met Deltares en HKV een data-assimilatietool ontwikkeld die ingezet kan worden om simulaties met het Landelijk Hydrologisch Model te verbeteren