1,031 research outputs found

    Formation of Siderite in peat

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    I torva langs det NV utlÞpet fra Glesmyra er det funnet et 15 - 20 cm tykt lyst grÄtt sjikt l, 5 m nede i profilet. Aldersbestemmelse, rÞntgenbestemmelse og kjemiske analyser viser at dette er jernkarbonat (sideritt) dannet for 5700 Är siden. Det er diskutert hvordan dette sjiktet kan ha blitt dannet. Som konklusjon, har en kommet fram til at det har vÊrt en utfelling av jernhydroksyd i bekkelÞpet. I lÞpet av et visst tidsrom har pH i vannet steget noe ved at jernet ha blitt redusert og hydroksydene gÄtt i lÞsning. Ved kombinasjonen av stor konsentrasjon av Fe2+ og noe CO3-- (pÄ grunn av CO2 fra lufta og pH Þkning) sÄ overstiges lÞselighetsproduktet til FeCO3 og det blir felling. Innholdet av 13C indikerer at karbonatet stammer fra luften og ikke fra omsatt torv. Det lyse sjiktet av FeCO 3 inneholder ogsÄ en del organiske forbindelser som er noe yngre. Det antas at disse er transportert nedover i profilet og er adsorbert til jernkarbonatfellingen. 13C indikerer at disse forbindelsene stammer fra en meget godt omsatt torv rett over utfellingssjiktet. Vann-nivÄet har i senere Är sunket noe pÄ grunn av utgraving i bekkelÞpet. Det lyse laget som derved ble avdekket og gjort tilgjengelig for vann og luft, har blitt oksydert til FeOOH (gÞthitt) og kan sees langs lange strekninger av bekkelÞpet

    Iran transport and accumulation in profiles of a cuitivated peat land area

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    En mindre del av et stort dyrket myrareal pÄ eiendommen Vivang, VÄler i SolÞr, har uvanlig jernrik torv. Her har havre hatt god vegetativ vekst, men meget dÄrlig kjerneutvikling (5,10). Det siste har vist seg Ä skyldes molybdenmangel, som sÊrlig mÄ antas Ä ha Ärsakssammenheng med det store jerninnholdet i torva. I denne artikkelen er arealet med molybdenmangel kalt A og et tilgrensende areal uten synlige tegn til slik mangel B. Tabellene 1-3 viser kjemiske analyseresultater for torv fra 3 profiler pÄ A og ett pÄ B. Torv fra A har ekstremt stort Fe-innhold opp til 71 tonn/ dekar i et ca. 0,75 m torvlag og 37 tonn i et ca. 0,1 m tykt sjikt under plogsjiktet. Det store Fe-innholdet mÄ skrive seg fra forekomster av Fe-rike gabbroide bergarter og Fe-rike sandavsetninger i omgivelsene. [


    Molecular Basis of Enhanced Activity in Factor VIIa-Trypsin Variants Conveys Insights into Tissue Factor-mediated Allosteric Regulation of Factor VIIa Activity

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    The complex of coagulation factor VIIa (FVIIa), a trypsin-like serine protease, and membrane-bound tissue factor (TF) initiates blood coagulation upon vascular injury. Binding of TF to FVIIa promotes allosteric conformational changes in the FVIIa protease domain and improves its catalytic properties. Extensive studies have revealed two putative pathways for this allosteric communication. Here we provide further details of this allosteric communication by investigating FVIIa loop swap variants containing the 170 loop of trypsin that display TF-independent enhanced activity. Using x-ray crystallography, we show that the introduced 170 loop from trypsin directly interacts with the FVIIa active site, stabilizing segment 215–217 and activation loop 3, leading to enhanced activity. Molecular dynamics simulations and novel fluorescence quenching studies support that segment 215–217 conformation is pivotal to the enhanced activity of the FVIIa variants. We speculate that the allosteric regulation of FVIIa activity by TF binding follows a similar path in conjunction with protease domain N terminus insertion, suggesting a more complete molecular basis of TF-mediated allosteric enhancement of FVIIa activity

    Oil from transgenic Camelina sativa containing over 25 % n-3 long-chain polyunsaturated fatty acids as the major lipid source in feed for Atlantic salmon (Salmo salar)

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    Facing a bottleneck in the growth of aquaculture, and a gap in the supply and demand of the highly beneficial omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), sustainable alternatives to traditional marine–based feeds are required. Therefore, in the present trial, a novel oil obtained from a genetically engineered oilseed crop, Camelina sativa, that supplied over 25 % n-3 LC-PUFA was tested as a sole dietary added lipid source in Atlantic salmon (Salmo salar) feed. Three groups of fish were fed for 12 weeks three experimental diets with the same basal composition and containing 20 % added oil supplied by either a blend of fish oil and rapeseed oil (1:3) (COM) reflecting current commercial formulations, wild-type Camelina oil (WCO) or the novel transgenic Camelina oil (TCO). There were no negative effects on the growth, survival rate or health of the fish. The whole fish and flesh n-3 LC-PUFA levels were highest in fish fed TCO with levels almost and more than 2-fold higher compared to those of fish fed the COM and WCO diets, respectively. Diet TCO had no negative impacts on the evaluated immune and physiological parameters of head kidney monocytes. The transcriptomic responses of liver and mid-intestine showed only mild effects on metabolism genes. Overall, the results clearly indicated that the oil from transgenic Camelina was highly efficient in supplying n-3 LC-PUFA providing levels double that obtained with a current commercial standard, and similar to those a decade ago prior to substantial dietary fishmeal and oil replacement

    An oil containing EPA and DHA from transgenic Camelina sativa to replace marine fish oil in feeds for Atlantic salmon (Salmo salar L.): Effects on intestinal transcriptome, histology, tissue fatty acid profiles and plasma biochemistry

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    New de novo sources of omega 3 (n-3) long chain polyunsaturated fatty acids (LC-PUFA) are required as alternatives to fish oil in aquafeeds in order to maintain adequate levels of the beneficial fatty acids, eicosapentaenoic and docosahexaenoic (EPA and DHA, respectively). The present study investigated the use of an EPA+DHA oil derived from transgenic Camelina sativa in Atlantic salmon (Salmo salar) feeds containing low levels of fishmeal (35 %) and fish oil (10 %), reflecting current commercial formulations, to determine the impacts on tissue fatty acid profile, intestinal transcriptome, and health of farmed salmon. Post-smolt Atlantic salmon were fed for 12-weeks with one of three experimental diets containing either a blend of fish oil/rapeseed oil (FO), wild-type camelina oil (WCO) or transgenic camelina oil (DCO) as added lipid source. The DCO diet did not affect any of the fish performance or health parameters studied. Analyses of the mid and hindgut transcriptomes showed only mild effects on metabolism. Flesh of fish fed the DCO diet accumulated almost double the amount of n-3 LC-PUFA than fish fed the FO or WCO diets, indicating that these oils from transgenic oilseeds offer the opportunity to increase the n-3 LC-PUFA in farmed fish to levels comparable to those found a decade ago

    A systematic approach for evaluating the role of surface-exposed loops in trypsin-like serine proteases applied to the 170 loop in coagulation factor VIIa

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    Proteases play a major role in many vital physiological processes. Trypsin-like serine proteases (TLPs), in particular, are paramount in proteolytic cascade systems such as blood coagulation and complement activation. The structural topology of TLPs is highly conserved, with the trypsin fold comprising two ÎČ-barrels connected by a number of variable surface-exposed loops that provide a surprising capacity for functional diversity and substrate specificity. To expand our understanding of the roles these loops play in substrate and co-factor interactions, we employ a systematic methodology akin to the natural truncations and insertions observed through evolution of TLPs. The approach explores a larger deletion space than classical random or directed mutagenesis. Using FVIIa as a model system, deletions of 1–7 amino acids through the surface exposed 170 loop, a vital allosteric regulator, was introduced. All variants were extensively evaluated by established functional assays and computational loop modelling with Rosetta. The approach revealed detailed structural and functional insights recapitulation and expanding on the main findings in relation to 170 loop functions elucidated over several decades using more cumbersome crystallization and single deletion/mutation methodologies. The larger deletion space was key in capturing the most active variant, which unexpectedly had a six-amino acid truncation. This variant would have remained undiscovered if only 2–3 deletions were considered, supporting the usefulness of the methodology in general protease engineering approaches. Our findings shed further light on the complex role that surface-exposed loops play in TLP function and supports the important role of loop length in the regulation and fine-tunning of enzymatic function throughout evolution

    Measuring the capability to raise revenue process and output dimensions and their application to the Zambia revenue authority

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    The worldwide diffusion of the good governance agenda and new public management has triggered a renewed focus on state capability and, more specifically, on the capability to raise revenue in developing countries. However, the analytical tools for a comprehensive understanding of the capability to raise revenue remain underdeveloped. This article aims at filling this gap and presents a model consisting of the three process dimensions ‘information collection and processing’, ‘merit orientation’ and ‘administrative accountability’. ‘Revenue performance’ constitutes the fourth capability dimension which assesses tax administration’s output. This model is applied to the case of the Zambia Revenue Authority. The dimensions prove to be valuable not only for assessing the how much but also the how of collecting taxes. They can be a useful tool for future comparative analyses of tax administrations’ capabilities in developing countries.Die weltweite Verbreitung der Good-Governance- und New-Public-Management-Konzepte hat zu einer zunehmenden Konzentration auf staatliche LeistungsfĂ€higkeit und, im Besonderen, auf die LeistungsfĂ€higkeit der Steuererhebung in EntwicklungslĂ€ndern gefĂŒhrt. Allerdings bleiben die analytischen Werkzeuge fĂŒr ein umfassendes VerstĂ€ndnis von LeistungsfĂ€higkeit unterentwickelt. Dieser Artikel stellt hierfĂŒr ein Modell vor, das die drei Prozess-Dimensionen „Sammeln und Verarbeiten von Informationen“, „Leistungsorientierung der Mitarbeiter“ und „Verantwortlichkeit der Verwaltung“ beinhaltet. „Einnahmeperformanz“ ist die vierte Dimension und erfasst den Output der Steuerverwaltung. Das mehrdimensionale Modell wird fĂŒr die Analyse der LeistungsfĂ€higkeit der Steuerbehörde Zambias (Zambia Revenue Authority) genutzt. Es erweist sich nicht nur fĂŒr die Untersuchung des Wieviel, sondern auch des Wie des Erhebens von Steuern als wertvoll. Die vier Dimensionen können in Zukunft zur umfassenden und vergleichenden Analyse der LeistungsfĂ€higkeit verschiedener Steuerverwaltungen in EntwicklungslĂ€ndern genutzt werden
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