Records 21 - 40 / 519
Probabilistic maize yield prediction over East Africa using dynamic ensemble seasonal climate forecasts
Ogutu, Geoffrey E.O. ; Franssen, Wietse H.P. ; Supit, Iwan ; Omondi, P. ; Hutjes, Ronald W.A. - \ 2018
Agricultural and Forest Meteorology 250-251 (2018). - ISSN 0168-1923 - p. 243 - 261.
Crop models - Dynamic crop forecasting - East Africa - Forecast lead-time - Probabilistic ensemble prediction - Rainfed agriculture
We tested the usefulness of seasonal climate predictions for impacts prediction in eastern Africa. In regions where these seasonal predictions showed skill we tested if the skill also translated into maize yield forecasting skills. Using European Centre for Medium-Range Weather Forecasts (ECMWF) system-4 ensemble seasonal climate hindcasts for the period 1981–2010 at different initialization dates before sowing, we generated a 15-member ensemble of yield predictions using the World Food Studies (WOFOST) crop model implemented for water-limited maize production and single season simulation. Maize yield predictions are validated against reference yield simulations using the WATCH Forcing Data ERA-Interim (WFDEI), focussing on the dominant sowing dates in the northern region (July), equatorial region (March-April) and in the southern region (December). These reference yields show good anomaly correlations compared to the official FAO and national reported statistics, but the average reference yield values are lower than those reported in Kenya and Ethiopia, but slightly higher in Tanzania. We use the ensemble mean, interannual variability, mean errors, Ranked Probability Skill Score (RPSS) and Relative Operating Curve skill Score (ROCSS) to assess regions of useful probabilistic prediction. Annual yield anomalies are predictable 2-months before sowing in most of the regions. Difference in interannual variability between the reference and predicted yields range from ±40%, but higher interannual variability in predicted yield dominates. Anomaly correlations between the reference and predicted yields are largely positive and range from +0.3 to +0.6. The ROCSS illustrate good pre-season probabilistic prediction of above-normal and below-normal yields with at least 2-months lead time. From the sample sowing dates considered, we concluded that, there is potential to use dynamical seasonal climate forecasts with a process based crop simulation model WOFOST to predict anomalous water-limited maize yields.
Enzymatic halogenation and oxidation using an alcohol oxidase-vanadium chloroperoxidase cascade
But, Andrada ; Noord, Aster Van; Poletto, Francesca ; Sanders, Johan P.M. ; Franssen, Maurice C.R. ; Scott, Elinor L. - \ 2017
Molecular Catalysis 443 (2017). - ISSN 2468-8231 - p. 92 - 100.
The chemo-enzymatic cascade which combines alcohol oxidase from Hansenula polymorpha (AOXHp) with vanadium chloroperoxidase (VCPO), for the production of biobased nitriles from amino acids was investigated. In the first reaction H2O2 (and acetaldehyde) are generated from ethanol and oxygen by AOXHp. H2O2 is subsequently used in the second reaction by VCPO to produce HOBr in situ. HOBr is required for the non-enzymatic oxidative decarboxylation of glutamic acid (Glu) to 3-cyanopropanoic acid (CPA), an intermediate in the production of biobased acrylonitrile. It was found that during the one pot conversion of Glu to CPA by AOXHp-VCPO cascade, AOXHp was deactivated by HOBr. To avoid deactivation, the two enzymes were separated in two fed-batch reactors. The deactivation of AOXHp by HOBr appeared to depend on the substrate: an easily halogenated compound like monochlorodimedone (MCD) was significantly converted in one pot by the cascade reaction of AOXHp and VCPO, while conversion of Glu did not occur under those conditions. Apparently, MCD scavenges HOBr before it can inactivate AOXHp, while Glu reacts slower, leading to detrimental concentrations of HOBr. Enzymatically generated H2O2 was used in a cascade reaction involving halogenation steps to enable the co-production of biobased nitriles and acetaldehyde.
Ambient characterization of synthetic fibers by laser ablation electrospray ionization mass spectrometry
Geenen, F.A.M.G. van; Franssen, M.C.R. ; Schotman, A.H.M. ; Zuilhof, H. ; Nielen, M.W.F. - \ 2017
Analytical Chemistry 89 (2017). - ISSN 0003-2700 - p. 4031 - 4037.
Direct analysis of synthetic fibers under ambient
conditions is highly desired to identify the polymer, the finishes
applied and irregularities that may compromise its performance
and value. In this paper, laser ablation electrospray ionization
ion mobility time-of-flight mass spectrometry (LAESI-IMSTOF-
MS) was used for the analysis of synthetic polymers and
fibers. The key to this analysis was the absorption of laser light
by aliphatic and aromatic nitrogen functionalities in the
polymers. Analysis of polyamide (PA) 6, 46, 66, and 12 pellets
and PA 6, 66, polyaramid and M5 fibers yielded characteristic
fragment ions without any sample pretreatment, enabling their
unambiguous identification. Synthetic fibers are, in addition,
commonly covered with a surface layer for improved adhesion
and processing. The same setup, but operated in a transient infrared matrix-assisted laser desorption electrospray ionization (IRMALDESI)
mode, allowed the detailed characterization of the fiber finish layer and the underlying polymer. Differences in finish
layer distribution may cause variations in local properties of synthetic fibers. Here we also show the feasibility of mass
spectrometry imaging (MSI) of the distribution of a finish layer on the synthetic fiber and the successful detection of local surface
|Genome of the obligately alkaliphilic fungus Sodiomyces alkalinus reveals its adaptations to high pH.
Grum-Grzhimaylo, A. ; Falkoski, D.L. ; Heuvel, Joost van den; Min, B. ; Choi, I.G. ; Henrissat, Bernard ; Franssen, H.G.J.M. ; Bilanenko, E.N. ; Vries, Ronald P. De; Kan, J.A.L. van; Grigoriev, I.V. ; Debets, A.J.M. - \ 2017
In: Abstract Book 29th Fungal Genetics Conference Asilomar 17, Pacific Grove, CA, USA 14-19 March 2017. - Genetics Society of America - p. 152 - 152.
Alkaliphilic fungi, i.e. fungi that grow optimally at high pH, are exceptional with only a handful of species described to date. Here, we sequenced the obligate alkaliphilic ascomycete S. alkalinus isolated from alkaline soda soils, and explored the features responsible for its unusual life-style. We found that PacC, the major regulator of alkaline-related genes, is up-regulated at higher pH values than PacC orthologues of neutrophilic species. To assess how this fungus can degrade carbohydrate sources under extremely alkalic conditions, we searched for the CAZymes encoded in the genome of S. alkalinus and performed enzyme assays. We revealed many cellulases, but their overall activity was low presumably because of slower induction. Although cellulolytic and hemicellulolytic activity was optimal at pH 6, there still was some activity at pH 10, at which pH it was completely absent in the neutrophilic A. oryzae. Excellent in vitro growth on xylan indicates that grasses are the preferred nutritional source for S. alkalinus in nature. We detected potent proteolytic activity at alkaline pH, compared to the neutrophilic A. oryzae, which may reflect the need for obtaining extra nitrogen, as this essential element becomes limiting at alkaline conditions. Proteins of bacterial cells, which are present in bulk at soda lakes, seem the likely source of nitrogen. In support of this hypothesis, we found several instances of horizontal transfer of prokaryotic genes into the genome of S. alkalinus, encoding enzymes that degrade bacterial cell walls. The genome of S. alkalinus will provide a valuable source to further study the biology and evolution of alkaliphilic trait in fungi with respect to neutrophilic species. In addition, it may provide alkaline-active metabolites of commercial interest.
Identification of a drimenol synthase and drimenol oxidase from Persicaria hydropiper, involved in the biosynthesis of insect deterrent drimanes
Henquet, M.G.L. ; Prota, N. ; Hooft, J.J.J. van der; Varbanova, M. ; Hulzink, R.J.M. ; Vos, M. de; Prins, M. ; Both, M.T.J. de; Franssen, M.C.R. ; Bouwmeester, H.J. ; Jongsma, M.A. - \ 2017
The Plant Journal 90 (2017)6. - ISSN 0960-7412 - p. 1052 - 1063.
The sesquiterpenoid polygodial, belonging to the drimane family, has been shown to be an antifeedant for a number of herbivorous insects. It is presumed to be synthesized from farnesyl diphosphate via drimenol, subsequent C-12 hydroxylation, and further oxidations at both C-11 and C-12 to form a dialdehyde. Here, we have identified a drimenol synthase (PhDS) and a cytochrome P450 drimenol oxidase (PhDOX1) from Persicaria hydropiper. Expression of PhDS in yeast and plants resulted in production of drimenol only. Co-expression of PhDS with PhDOX1 in yeast yielded drimendiol, the 12-hydroxylation product of drimenol, as a major product, and cinnamolide. When PhDS and PhDOX1 were transiently expressed by agro-infiltration in Nicotiana benthamiana leaves, drimenol was almost completely converted into cinnamolide and several additional drimenol derivatives were observed. In vitro assays showed that PhDOX1 only catalyzes the conversion from drimenol to drimendiol, and not the further oxidation into an aldehyde. In yeast and heterologous plant hosts, the C-12 position of drimendiol is therefore likely further oxidized by endogenous enzymes into an aldehyde and subsequently converted to cinnamolide, presumably by spontaneous hemiacetal formation with the C-11 hydroxyl group followed by oxidation. Purified cinnamolide was confirmed by NMR and shown to be deterrent with an effective deterrent dose (ED50 ) of ~200-400 μg gFW-1 against both whiteflies and aphids. The putative additional physiological and biochemical requirements for polygodial biosynthesis and stable storage in plant tissues are discussed
The impact of dietary protein or amino acid supplementation on muscle mass and strength in elderly people : Individual participant data and meta-analysis of RCT’s
Tieland, M. ; Franssen, R. ; Dullemeijer, C. ; Dronkelaar, C. van; Kim, H.K. ; Ispoglou, T. ; Zhu, K. ; Prince, R.L. ; Loon, L.J.C. van; Groot, Lisette C.P.G.M. de - \ 2017
Journal of Nutrition, Health and Aging 21 (2017)9. - ISSN 1279-7707 - p. 994 - 1001.
Objectives: Increasing protein or amino acid intake has been promoted as a promising strategy to increase muscle mass and strength in elderly people, however, long-term intervention studies show inconsistent findings. Therefore, we aim to determine the impact of protein or amino acid supplementation compared to placebo on muscle mass and strength in older adults by combining the results from published trials in a metaanalysis and pooled individual participant data analysis. Design: We searched Medline and Cochrane databases and performed a meta-analysis on eight available trials on the effect of protein or amino acid supplementation on muscle mass and strength in older adults. Furthermore, we pooled individual data of six of these randomized double-blind placebo-controlled trials. The main outcomes were change in lean body mass and change in muscle strength for both the meta-analysis and the pooled analysis. Results: The meta-analysis of eight studies (n=557) showed no significant positive effects of protein or amino acid supplementation on lean body mass (mean difference: 0.014 kg: 95% CI -0.152; 0.18), leg press strength (mean difference: 2.26 kg: 95% CI -0.56; 5.08), leg extension strength (mean difference: 0.75 kg: 95% CI: -1.96, 3.47) or handgrip strength (mean difference: -0.002 kg: 95% CI -0.182; 0.179). Likewise, the pooled analysis showed no significant difference between protein and placebo treatment on lean body mass (n=412: p=0.78), leg press strength (n=121: p=0.50), leg extension strength (n=121: p=0.16) and handgrip strength (n=318: p=0.37). Conclusions: There is currently no evidence to suggest that protein or amino acid supplementation without concomitant nutritional or exercise interventions increases muscle mass or strength in predominantly healthy elderly people.
Cis-regulatory PLETHORA promoter elements directing root and nodule expression are conserved between Arabidopsis thaliana and Medicago truncatula
Franssen, H.G.J.M. ; Kulikova, O. ; Willemsen, V.A. ; Heidstra, R. - \ 2017
Plant Signaling & Behavior 12 (2017)2. - ISSN 1559-2316
Nodules are unique organs formed on roots of legumes by soil-borne bacteria, collectively known as rhizobium. Recently, we have shown that orthologs of the AINTEGUMENTA-like (AIL) AP2 transcription factors PLETHORA (PLT) 1 to 4, that redundantly regulate Arabidopsis thaliana root development are involved in root and nodule growth in Medicago truncatula. Hence, it is conceivable that rhizobium has co-opted these genes for nodule development. Whether this co-option requires the presence of specific cis-elements in the promoters and/or specialization of PLT protein function is not clear. Here, we analyzed the qualitative expression patterns of the Arabidopsis PLT1 to 4 promoters in Medicago roots and nodules and compared these with the described expression patterns of the Medicago PLT genes. Our studies reveal that the expression patterns of the investigated promoters and their Medicago orthologs are very similar, indicating that at least all cis-elements regulating spatial PLT expression are conserved among the Arabidopsis and Medicago PLT1 to 4 promoters.
Impacts on river systems under 2 °C warming : Bangladesh Case Study
Zaman, A.M. ; Molla, M.K. ; Pervin, I.A. ; Mahbubur Rahman, S.M. ; Haider, A.S. ; Ludwig, F. ; Franssen, W. - \ 2017
Climate Services 7 (2017). - ISSN 2405-8807 - p. 96 - 114.
Bangladesh - Basin model - Climate change - Hydrodynamic model - Regional Climatic Model (RCM) - Salinity intrusion - Sea level rise
Bangladesh is particularly vulnerable due to the combined impacts of sea level rise, rainfall and runoff variability, and changes in cyclone patterns. This paper presents the application of an integrated modelling framework used to investigate climate change impacts when global averaged surface temperature increases by 2. C from pre-industrial level. The modelling framework consists of four model types: Regional climate model (RCM), Ganges-Brahmaputra-Meghna (GBM) Basin model, Southwest Region Hydrodynamic and Salinity models. Bias corrected climate results (temperature, precipitation and evapotranspiration) from SMHI-RCA and CNRM-ARPEGE RCMs for (Representative Concentration Pathway) RCP 8.5 scenario were used. The uniqueness of this research study was that the same GCM (General Circulation Model)/RCM results were used across the whole modelling chain. In Bagerhat District, it was found that river salinity can increase by about 0.5 to 2 PPT (parts per thousand). Also, the duration of river salinity above 1 PPT can double in some locations. In Kushtia District, in the months of November and December river flows may increase but not sufficiently in other months due to lack of connectivity to the Ganges River. In the flood-prone Shariatpur District, average wet season water level increases up to 0.2 to 0.5. m. Also, duration of flood levels above the established danger level can double in some locations. Finally, this study found that dredging of the mouth of the Gorai River (in Kushtia District) is an effective adaptation measure. The dredging ensures connectivity to the Ganges River, which allows freshwater to enter the Southwest region of Bangladesh, which not only alleviates drought conditions in Kushtia Distract but also helps push back saline intrusion.
Gram-positive anaerobe cocci are underrepresented in the microbiome of filaggrin-deficient human skin : Letter to the editor
Zeeuwen, Patrick L.J.M. ; Ederveen, Thomas H.A. ; Krieken, Danique A. van der; Niehues, Hanna ; Boekhorst, Jos ; Kezic, Sanja ; Hanssen, Daniëlle A.T. ; Otero, Marisol E. ; Hanssen, Daniëlle A.T. ; Rodijk-Olthuis, Diana ; Falcone, Denise ; Bogaard, Ellen H.J. van den; Kamsteeg, Marijke ; Koning, Heleen D. de; Zeeuwen-Franssen, Manon E.J. ; Steensel, Maurice A.M. van; Kleerebezem, Michiel ; Timmerman, Harro M. ; Hijum, Sacha A.F.T. van; Schalkwijk, Joost - \ 2017
Journal of Allergy and Clinical Immunology 139 (2017)4. - ISSN 0091-6749 - p. 1368 - 1371.
Skill of ECMWF system-4 ensemble seasonal climate forecasts for East Africa
Ogutu, Geoffrey E.O. ; Franssen, Wietse H.P. ; Supit, Iwan ; Omondi, P. ; Hutjes, Ronald W.A. - \ 2017
International Journal of Climatology 37 (2017)5. - ISSN 0899-8418 - p. 2734 - 2756.
Bias correction - East Africa - Ensemble prediction - Probabilistic verification - Seasonal climate forecasts
This study evaluates the potential use of the ECMWF System-4 seasonal forecasts (S4) for impact analysis over East Africa. For use, these forecasts should have skill and small biases. We used the 15-member ensemble of 7-month forecasts initiated every month, and tested forecast skill of precipitation (tp), near-surface air temperature (tas) and surface downwelling shortwave radiation (rsds). We validated the 30-year (1981-2010) hindcast version of S4 against the WFDEI reanalysis (WATCH Forcing Data ERA-Interim) and to independent relevant observational data sets. Probabilistic skill is assessed using anomaly correlation, ranked probability skill score (RPSS) and the relative operating curve skill score (ROCSS) at both grid cell and over six distinct homogeneous rainfall regions for the three growing seasons of East Africa (i.e. MAM, JJA and OND). S4 exhibits a wet bias in OND, a dry bias in MAM and a mix of both in JJA. Temperature biases are similar in all seasons, constant with lead-time and correlate with elevation. Biases in rsds correlate with cloud/rain patterns. Bias correction clears biases but does not affect probabilistic skills. Predictability of the three variables varies with season, location and lead-time. The choice of validating dataset plays little role in the regional patterns and magnitudes of probabilistic skill scores. The OND tp forecasts show skill over a larger area up to 3 months lead-time compared to MAM and JJA. Upper- and lower-tercile tp forecasts are 20-80% better than climatology. Temperature forecasts are skillful for at least 3months lead-time and they are 40-100% better than climatology. The rsds is less skillful than tp and tas in all seasons when verified against WFDEI but higher in all lead months against the alternative datasets. The forecast system captures El-Niño Southern Oscillation (ENSO)-related anomalous years with region-dependent skill.
Habituation to low or high protein intake does not modulate basal or postprandial muscle protein synthesis rates: a randomized trial
Gorissen, S.H. ; Horstman, Astrid ; Franssen, Rinske ; Kouw, I.W. ; Wall, B.T. ; Burd, N.A. ; Groot, C.P.G.M. de; Loon, L.J.C. van - \ 2017
American Journal of Clinical Nutrition 105 (2017)2. - ISSN 0002-9165 - p. 332 - 342.
Background: Muscle mass maintenance is largely regulated by basal muscle protein synthesis rates and the ability to increase muscle protein synthesis after protein ingestion. To our knowledge, no previous studies have evaluated the impact of habituation to either low protein intake (LOW PRO) or high protein intake (HIGH PRO) on the postprandial muscle protein synthetic response. Objective: We assessed the impact of LOW PRO compared with HIGH PRO on basal and postprandial muscle protein synthesis rates after the ingestion of 25 g whey protein. Design: Twenty-four healthy, older men [age: 62 ± 1 y; body mass index (in kg/m2): 25.9 ± 0.4 (mean ± SEM)] participated in a parallel-group randomized trial in which they adapted to either a LOW PRO diet (0.7 g · kg–1 · d−1; n = 12) or a HIGH PRO diet (1.5 g · kg–1 · d–1; n = 12) for 14 d. On day 15, participants received primed continuous l-[ring-2H5]-phenylalanine and l-[1-13C]-leucine infusions and ingested 25 g intrinsically l-[1-13C]-phenylalanine– and l-[1-13C]-leucine–labeled whey protein. Muscle biopsies and blood samples were collected to assess muscle protein synthesis rates as well as dietary protein digestion and absorption kinetics. Results: Plasma leucine concentrations and exogenous phenylalanine appearance rates increased after protein ingestion (P < 0.01) with no differences between treatments (P > 0.05). Plasma exogenous phenylalanine availability over the 5-h postprandial period was greater after LOW PRO than after HIGH PRO (61% ± 1% compared with 56% ± 2%, respectively; P < 0.05). Muscle protein synthesis rates increased from 0.031% ± 0.004% compared with 0.039% ± 0.007%/h in the fasted state to 0.062% ± 0.005% compared with 0.057% ± 0.005%/h in the postprandial state after LOW PRO compared with HIGH PRO, respectively (P < 0.01), with no differences between treatments (P = 0.25). Conclusion: Habituation to LOW PRO (0.7 g · kg–1 · d–1) compared with HIGH PRO (1.5 g · kg–1 · d–1) augments the postprandial availability of dietary protein–derived amino acids in the circulation and does not lower basal muscle protein synthesis rates or increase postprandial muscle protein synthesis rates after ingestion of 25 g protein in older men. This trial was registered at clinicaltrials.gov as NCT01986842.
Biosensor comprising a modified metal surface and method for the modification of a metal surface
Alonso Carnicero, J.M. ; Franssen, M.C.R. ; Bielen, A.A.M. ; Scheres, L.M.W. ; Schütz-Trilling, A.K. ; Zeper, W.B. ; Zuilhof, J.T. ; Paassen, P.A.M. van; Olthuis, W. ; Rassaei, L. - \ 2016
Octrooinummer: WO2016018148, gepubliceerd: 2016-02-04.
The present invention relates to a device for the detection of an analyte in a fluid, the device comprising: (a) a working electrode comprising a modified metal surface, wherein: (1) the metal is selected from the group consisting of Ru, Rh, Pd, Ag, Ir, Pt and Au; (2) an enzyme is covalently attached to the metal surface via an alkyloxy or an alkenyloxy moiety and, optionally, a linker moiety; (3)the alkyloxy or alkenyloxy moiety is covalently bonded to said metal surface via the alkyloxy or alkenyloxy O- atom; and (4) the linker moiety, if present, is covalently bonded to theenzyme and to the alkyloxy or alkenyloxy moiety; (b) a reference electrode; and (c) means for detecting an electricalsignal, the means being operationally coupled to at least working electrode (a) and reference electrode (b). The device according to the invention is also referred to as a biosensor. The invention also relates to a process for the modification of a metal surface and to a modified metal surface obtainable by the process. Furthermore, the invention relates to an electrode comprising said modified metal surface, and to a biosensor comprising said modified metal surface.
Characterization of the laccase-mediated oligomerization of 4-hydroxybenzoic acid
Slagman, S. ; Escorihuela Fuentes, J. ; Zuilhof, H. ; Franssen, M.C.R. - \ 2016
RSC Advances : An international journal to further the chemical sciences 6 (2016)101. - ISSN 2046-2069 - p. 99367 - 99375.
Modifying inert poly(ethersulfone) membranes using laccase has proven to be an environmentally benign and easily applicable process to alter the membrane's surface properties. By this method phenolic acid monomers such as 4-hydroxybenzoic acid are grafted from the membrane surface to make it anti-fouling. In order to enhance the anti-fouling capabilities even further it is important to study the molecular details of this reaction. However, the nature of the products of laccase modification, either on a surface or in solution, has been studied only poorly. In this paper we report the formation of C3–C3′, C3–O and C1–C3′ linked dimers as the first products of the solution-phase laccase-mediated oligomerization of 4-hydroxybenzoic acid. These dimers can also act as substrate for laccase, and we show that their enzymatic oxidative coupling occurs far more rapidly than that of 4-hydroxybenzoic acid, which indicates that they are highly reactive intermediates that are efficiently polymerized onwards. The reactivity of each dimer is of large influence on its yield; dimers that are converted more rapidly are less abundant. This knowledge allows for further improvement of applications involving laccase such as the grafting of phenols on surfaces and enzymatic polymerization of lignin fragments.
Usefulness of ECMWF system-4 ensemble seasonal climate forecasts for East Africa
Ogutu, G.E.O. ; Franssen, W.H.P. ; Supit, I. ; Omondi, P. ; Hutjes, R.W.A. - \ 2016
Modeling soil processes : Review, key challenges, and new perspectives
Vereecken, H. ; Schnepf, A. ; Hopmans, J.W. ; Javaux, M. ; Or, D. ; Roose, T. ; Vanderborght, J. ; Young, M.H. ; Amelung, W. ; Aitkenhead, M. ; Allison, S.D. ; Assouline, S. ; Baveye, P. ; Berli, M. ; Brüggemann, N. ; Finke, P. ; Flury, M. ; Gaiser, T. ; Govers, G. ; Ghezzehei, T. ; Hallett, P. ; Hendricks Franssen, H.J. ; Heppell, J. ; Horn, R. ; Huisman, J.A. ; Jacques, D. ; Jonard, F. ; Kollet, S. ; Lafolie, F. ; Lamorski, K. ; Leitner, D. ; Mcbratney, A. ; Minasny, B. ; Montzka, C. ; Nowak, W. ; Pachepsky, Y. ; Padarian, J. ; Romano, N. ; Roth, K. ; Rothfuss, Y. ; Rowe, E.C. ; Schwen, A. ; Šimůnek, J. ; Tiktak, A. ; Dam, Jos van; Zee, S.E.A.T.M. van der; Vogel, H.J. ; Vrugt, J.A. ; Wöhling, T. ; Wöhling, T. ; Young, I.M. - \ 2016
Vadose Zone Journal 15 (2016)5. - ISSN 1539-1663 - 57 p.
The remarkable complexity of soil and its importance to a wide range of ecosystem services presents major challenges to the modeling of soil processes. Although major progress in soil models has occurred in the last decades, models of soil processes remain disjointed between disciplines or ecosystem services, with considerable uncertainty remaining in the quality of predictions and several challenges that remain yet to be addressed. First, there is a need to improve exchange of knowledge and experience among the different disciplines in soil science and to reach out to other Earth science communities. Second, the community needs to develop a new generation of soil models based on a systemic approach comprising relevant physical, chemical, and biological processes to address critical knowledge gaps in our understanding of soil processes and their interactions. Overcoming these challenges will facilitate exchanges between soil modeling and climate, plant, and social science modeling communities. It will allow us to contribute to preserve and improve our assessment of ecosystem services and advance our understanding of climate-change feedback mechanisms, among others, thereby facilitating and strengthening communication among scientific disciplines and society. We review the role of modeling soil processes in quantifying key soil processes that shape ecosystem services, with a focus on provisioning and regulating services. We then identify key challenges in modeling soil processes, including the systematic incorporation of heterogeneity and uncertainty, the integration of data and models, and strategies for effective integration of knowledge on physical, chemical, and biological soil processes. We discuss how the soil modeling community could best interface with modern modeling activities in other disciplines, such as climate, ecology, and plant research, and how to weave novel observation and measurement techniques into soil models. We propose the establishment of an international soil modeling consortium to coherently advance soil modeling activities and foster communication with other Earth science disciplines. Such a consortium should promote soil modeling platforms and data repository for model development, calibration and intercomparison essential for addressing contemporary challenges.
Self-assembled monolayers of 1-alkenes on oxidized platinum surfaces as platforms for immobilized enzymes for biosensing
Alonso, Jose Maria ; Bielen, Abraham A.M. ; Olthuis, Wouter ; Kengen, Servé W.M. ; Zuilhof, Han ; Franssen, Maurice C.R. - \ 2016
Applied Surface Science 383 (2016). - ISSN 0169-4332 - p. 283 - 293.
Enzyme immobilization - Lactate biosensor - Platinum - Self-assembled monolayers
Alkene-based self-assembled monolayers grafted on oxidized Pt surfaces were used as a scaffold to covalently immobilize oxidase enzymes, with the aim to develop an amperometric biosensor platform. NH2-terminated organic layers were functionalized with either aldehyde (CHO) or N-hydroxysuccinimide (NHS) ester-derived groups, to provide anchoring points for enzyme immobilization. The functionalized Pt surfaces were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (CA), infrared reflection absorption spectroscopy (IRRAS) and atomic force microscopy (AFM). Glucose oxidase (GOX) was covalently attached to the functionalized Pt electrodes, either with or without additional glutaraldehyde crosslinking. The responses of the acquired sensors to glucose concentrations ranging from 0.5 to 100 mM were monitored by chronoamperometry. Furthermore, lactate oxidase (LOX) and human hydroxyacid oxidase (HAOX) were successfully immobilized onto the PtOx surface platform. The performance of the resulting lactate sensors was investigated for lactate concentrations ranging from 0.05 to 20 mM. The successful attachment of active enzymes (GOX, LOX and HAOX) on Pt electrodes demonstrates that covalently functionalized PtOx surfaces provide a universal platform for the development of oxidase enzyme-based sensors.
The Material practices of quantification: Measuring ‘deprivation’ in the Amsterdam Neighbourhood Policy
Wilde, Mandy de; Franssen, Thomas - \ 2016
Critical Social Policy 36 (2016)4. - ISSN 0261-0183 - p. 489 - 510.
actor-network theory - evaluation - governmentality - quantification - social policy
The use of indicators and indexes in social policy, as part of evidence-based policy, is understood by governmentality scholars as ‘techniques of governance’. However, we know very little about how the process of quantification is enacted in the material practices that constitute social policy itself. In this article we focus on a particular quantified object: the ‘Normal Amsterdam Level’ (NAP), used in an Amsterdam Neighbourhood Policy programme. We follow the NAP from its birth, to its life and its afterlife. We show that the qualification ‘deprived’ calls forth a whole set of problematic arrangements which are lost in a process of quantification. We understand the NAP as a generative device that actively assembles and arranges the world. These assemblages are rendered ‘hard’ through semiotic, statistical and visual techniques that produce facts about targeted neighbourhoods in relation to a city-wide average, thus serving as evidence and legitimisation for policy interventions.
Seasonal forecasting of european river discharge: hindcast verification of VIC and LPJML models driven by ECMWF System4
Greuell, J.W. - \ 2015
In: Seasonal Hydrobiological Forecasting Workshop Book of Abstracts. - - p. 29 - 30.
hindcast verification, river discharge, VIC model, LPJmL model
The hydrological models VIC (Liang, Lettenmaier et al. 1994) and LPJmL (Gerten, Schaphoff et al. 2004) have been widely used for the assessment of climate change impacts on water resources and water dependent sectors, stand-alone (van Vliet, Franssen et al. 2013) and as part of multi-model ensemble studies (Haddeland, Clark et al. 2011, Prudhomme, Giuntoli et al. 2014). Here we implement the same models to assess their capabilities for seasonal forecasting purposes. We analyse whether any forecasting skill present in seasonal meteorological forecasts propagates into skill in hydrological forecasts.
The VIC and LPJmL models are implemented for the European domain, including routing schemes on a 0.5o grid. As research models, LPJmL model parameters are not calibrated for discharge and VIC only crudely. Baseline runs and model spin up are driven by WFD-EI data (Weedon, Gomes et al. 2011). Hindcast runs are driven by the full 15 member, 30 year, monthly initiated, 7 month forecasts of the ECMWF System4 (Molteni, Stockdale et al. 2011). Each model is driven by both raw forecast data and by the same data bias-corrected against the WFD-EI data. Skill is assessed by ROCSS and RPSS scores of the three terciles (above normal, near normal and below normal), primarily for discharge against both baseline simulations and against observations (mainly obtained from GRDC) from 46 stations covering the whole of the European domain and for other water balance terms against baseline simulations only.
Skills will be presented grouped by the major European climatic zones, as a function of lead time and season. Tentative results show considerable skill in northern Europe for positive and negative spring anomalies with up to 2 months lead time, but decreasing for summer. For central Europe the performance is similar, for western Europe we find very little skill, while for the Iberian peninsula we find some skill for negative anomalies in summer with considerable lead time. More robust results will be presented at the workshop.
Bicarbonaat doodt schurftspore bij curatieve toepassing
Jong, P.F. de; Anbergen, R.H.N. ; Elk, P.J.H. van; Dieren, M.C.A. van; Steeg, P. van der; Franssen-Verheijen, M.A.W. - \ 2015
|Enzymes for materials: laccase-mediated modification of poly(ethersulfone) membranes
Franssen, M.C.R. ; Slagman, S. ; Nady, N. ; Schroen, C.G.P.H. ; Boom, R.M. ; Zuilhof, H. - \ 2015