The influence of gas and humidity on the mineralogy of various salt compositions – implications for natural and technical caverns

Storage caverns are increasingly located in heterogeneous salt deposits and filled with various fluids. The knowledge of phase behaviour in heterogeneous systems of salt, liquid and gas and the requirements for reliable analytical techniques is, therefore, of growing interest. A method that allows for the continuous monitoring of mineral compositions at distinct humidity and gas content using XRD measurements is presented here. Various saliniferous mineral compositions have been investigated in pure CO2, N2 or CH4 atmospheres with varying humidity in a closed chamber. All mineral compositions experience dissolution and/or mineral conversion reaction accompanied by volume loss. Dissolution-recrystallization reactions of complex mineral assemblages involving halite, sylvite, kieserite, carnallite and kainite were observed using this method. For carnallite-rich mineral assemblages, the mineral conversion from carnallite to sylvite was observed when humidity exceeded 50&thinsp;%&thinsp;RH. In the presence of CO2, acidification of the aqueous phase occurs which enhances the dissolution rate and reaction kinetics.</p

Elemental Composition of Natural Nanoparticles and Fine Colloids in European Forest Stream Waters and Their Role as Phosphorus Carriers

"This is the peer reviewed version of the following article: Gottselig, N., W. Amelung, J. W. Kirchner, R. Bol, W. Eugster, S. J. Granger, C. Hernández-Crespo, et al. 2017. Elemental Composition of Natural Nanoparticles and Fine Colloids in European Forest Stream Waters and Their Role as Phosphorus Carriers. Global Biogeochemical Cycles 31 (10). American Geophysical Union (AGU): 1592 1607. doi:10.1002/2017gb005657, which has been published in final form at https://doi.org/10.1002/2017GB005657. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] Biogeochemical cycling of elements largely occurs in dissolved state, but many elements may also be bound to natural nanoparticles (NNP, 1-100 nm) and fine colloids (100-450 nm). We examined the hypothesis that the size and composition of stream water NNP and colloids vary systematically across Europe. To test this hypothesis, 96 stream water samples were simultaneously collected in 26 forested headwater catchments along two transects across Europe. Three size fractions (similar to 1-20 nm, >20-60 nm, and >60 nm) of NNP and fine colloids were identified with Field Flow Fractionation coupled to inductively coupled plasma mass spectrometry and an organic carbon detector. The results showed that NNP and fine colloids constituted between 2 +/- 5% (Si) and 53 +/- 21% (Fe; mean +/- SD) of total element concentrations, indicating a substantial contribution of particles to element transport in these European streams, especially for P and Fe. The particulate contents of Fe, Al, and organic C were correlated to their total element concentrations, but those of particulate Si, Mn, P, and Ca were not. The fine colloidal fractions >60 nm were dominated by clay minerals across all sites. The resulting element patterns of NNP <60 nm changed from North to South Europe from Fe-to Ca-dominated particles, along with associated changes in acidity, forest type, and dominant lithology.The authors gratefully acknowledge the assistance of the following people in locating suitable sampling sites, contacting site operators, performing the sampling, and providing data: A. Avila Castells (Autonomous University of Barcelona), R. Batalla (University of Lleida), P. Blomkvist (Swedish University of Agricultural Sciences), H. Bogena (Julich Research Center), A.K. Boulet (University of Aveiro), D. Estany (University of Lleida), F. Garnier (French National Institute of Agricultural Research), H.J. Hendricks-Franssen (Research Center Julich), L. JacksonBlake (James Hutton Institute, NIVA), T. Laurila (Finnish Meteorological Institute), A. Lindroth (Lund University), M.M. Monerris (Universitat Politecnica de Valencia), M. Ottosson Lofvenius (Swedish University of Agricultural Sciences), I. Taberman (Swedish University of Agricultural Sciences), F. Wendland (Research Center Julich), T. Zetterberg (Swedish University of Agricultural Sciences and The Swedish Environmental Research Institute, IVL) and further unnamed contributors. The Swedish Infrastructure for Ecosystem Science (SITES) and the Swedish Integrated Monitoring, the latter financed by the Swedish Environmental Protection Agency, and ICOS Sweden have supported sampling and provided data for the Swedish sites. J.J.K. gratefully acknowledges the support from CESAM (UID/AMB/50017/2013), funded by the FCT/MCTES (PIDDAC) with cofunding by FEDER through COMPETE. N.G. gratefully acknowledges all those who contributed to organizing and implementing the continental sampling. The raw data can be found at http://hdl.handle.net/2128/14937. This project was partly funded by the German Research Foundation (DFG KL2495/1-1).Gottselig, N.; Amelung, W.; Kirchner, J.; Bol, R.; Eugster, W.; Granger, S.; Hernández Crespo, C.... 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Subduction or sagduction? Ambiguity in constraining the origin of ultramafic–mafic bodies in the Archean crust of NW Scotland

The Lewisian Complex of NW Scotland is a fragment of the North Atlantic Craton. It comprises mostly Archean tonalite–trondhjemite–granodiorite (TTG) orthogneisses that were variably metamorphosed and reworked in the late Neoarchean to Paleoproterozoic. Within the granulite facies central region of the mainland Lewisian Complex, discontinuous belts composed of ultramafic–mafic rocks and structurally overlying garnet–biotite gneiss (brown gneiss) are spatially associated with steeply-inclined amphibolite facies shear zones that have been interpreted as terrane boundaries. Interpretation of the primary chemical composition of these rocks is complicated by partial melting and melt loss during granulite facies metamorphism, and contamination with melts derived from the adjacent migmatitic TTG host rocks. Notwithstanding, the composition of the layered ultramafic–mafic rocks is suggestive of a protolith formed by differentiation of tholeiitic magma, where the ultramafic portions of these bodies represent the metamorphosed cumulates and the mafic portions the metamorphosed fractionated liquids. Although the composition of the brown gneiss does not clearly discriminate the protolith, it most likely represents a metamorphosed sedimentary or volcano-sedimentary sequence. For Archean rocks, particularly those metamorphosed to granulite facies, the geochemical characteristics typically used for discrimination of paleotectonic environments are neither strictly appropriate nor clearly diagnostic. Many of the rocks in the Lewisian Complex have ‘arc-like’ trace element signatures. These signatures are interpreted to reflect derivation from hydrated enriched mantle and, in the case of the TTG gneisses, partial melting of amphibolite source rocks containing garnet and a Ti-rich phase, probably rutile. However, it is becoming increasingly recognised that in Archean rocks such signatures may not be unique to a subduction environment but may relate to processes such as delamination and dripping. Consequently, it is unclear whether the Lewisian ultramafic–mafic rocks and brown gneisses represent products of plate margin or intraplate magmatism. Although a subduction-related origin is possible, we propose that an intraplate origin is equally plausible. If the second alternative is correct, the ultramafic–mafic rocks and brown gneisses may represent the remnants of intracratonic greenstone belts that sank into the deep crust due to their density contrast with the underlying partially molten low viscosity TTG orthogneisses

Entwicklung eines chirurgischen Curriculums für die Mastoidektomie unter Berücksichtigung der evidenzbasierten Datenlage und Kosteneffizienz

Einleitung: Die traditionelle Ausbildung im Operationssaal wird zunehmend durch das Training am Modell ergänzt. Für die ohrchirurgische Ausbildung, hier dargestellt an der Mastoidektomie, stehen neben nativen Humanfelsenbeinen weitere Trainingsmodelle, wie das Kunststofffelsenbein oder Computersimulatoren, zur Verfügung. Bisher gibt es kein strukturiertes Ausbildungskonzept, welches die unterschiedlichen Trainingsmethoden der Mastoidektomie hinsichtlich Wirksamkeit und Kosten integriert.Methoden: Für die Erstellung des otochirurgischen Curriculums erfolgte eine selektive Literaturrecherche. Berücksichtigt wurden lerntheoretische Erkenntnisse und die Verfügbarkeit sowie Wirksamkeit derzeit vorhandener Trainingsmodelle. Für die Wirtschaftlichkeitsanalyse wurde die Nutzenschwelle bestimmt. Ergebnisse: Zur Aneignung technischer Fähigkeiten empfiehlt sich ein stufenweises Vorgehen, welches leistungsabhängig die Präparation am Computersimulator, Kunststofffelsenbein und Leichenfelsenbein vorsieht. Quantitativ sind zur Erreichung eines Lernkurvenplateaus 25 teilautonome Präparationen anzustreben. Qualitativ sollte die technische Leistungsfähigkeit stufenabhängig durch eine metrische Analyse, Endproduktanalyse, Gesamtbewertungsskala und Checkliste prozeduraler Schritte objektiviert werden. Wirtschaftlich ist das Training ab einer ausbildungsbedingten Verlängerung der regulären Operationsdauer von 22%. Die Anschaffungskosten hätten sich unter optimalen Bedingungen nach der Ausbildung von 7 Assistenten amortisiert.Schlussfolgerungen: Das erstellte Curriculum integriert erstmals die verschiedenen Trainingsmodelle der Mastoidektomie in ein Gesamtkonzept. Der erstellte Ausbildungsplan ist kontinuierlich neuen Erkenntnissen und technischen Weiterentwicklungen anzupassen.Der Erstautor gibt keinen Interessenkonflikt an

Effect of divergent selection for yearling growth rate on protein metabolism in hind-limb muscle and whole body of Angus cattle

The impact of divergent selection for daily gain from birth to 1 year of age on protein metabolism in muscle and whole body was evaluated in 12-month-old Angus steers from the Trangie (NSW, Australia) selection experiment [Parnell, P.F., Herd, R.M., Perry, D., Bootle, B., 1994. The Trangie experiment-responses in growth rate, size, maternal ability, reproductive performance, carcass composition, feed requirements and herd profitability. Proc. Aust. Soc. Anim. Prod., 20: 17-20.]. The steers used from these lines differ in yearling weight by 40%. Eight steers from each of the high and low yearling growth rate lines were studied. Four steers from each line were fed to maintain weight and four fed at 1.6 times maintenance. In the whole body there were no significant between-line differences in flux of phenylalanine (Phe, a gross indicator of whole body protein synthesis). Mean values were, respectively, 0.99±0.10 and 1.07±0.11 μmol Phe/min/kg liveweight for high and low growth-lines. However, in hind-limb muscle, cattle selected for high growth rate had lower rates of protein synthesis and degradation than those selected for low growth rate. Low growth-line cattle were more sensitive to nutrition than high growth-line cattle, increasing their hind-limb muscle protein synthesis and oxygen consumption in response to increased feed intake to a greater extent than high growth-line steers (protein synthesis 215, 205, 424 and 264 nmol Phe/min/kg hind limb; oxygen uptake 110, 110, 141, 103 μmol O2/min/kg hind limb for high growth steers fed 1.6 and 1 times maintenance and low growth steers fed 1.6 and 1 times maintenance, respectively). These results are consistent with more efficient use of feed for liveweight gain in high growth-line steers. The results suggest that low growth-line steers have inherently higher rates of protein synthesis in muscle than do high growth-line steers, and that this may contribute in part to higher oxygen consumption in muscle, particularly at higher levels of feed intake. Based on the increment in hind-limb oxygen uptake in low line cattle with increased feed intake, it can be estimated that approximately 70% of the between-line difference in feed efficiency occurs in muscle