798 research outputs found

    Hydraulic conductivity distribution in crystalline rocks, derived from inflows to tunnels and galleries in the Central Alps, Switzerland

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    Inflow data from 23 tunnels and galleries, 136km in length and located in the Aar and Gotthard massifs of the Swiss Alps, have been analyzed with the objective (1) to understand the 3-dimensional spatial distribution of groundwater flow in crystalline basement rocks, (2) to assess the dependency of tunnel inflow rate on depth, tectonic overprint, and lithology, and (3) to derive the distribution of fracture transmissivity and effective hydraulic conductivity at the 100-m scale. Brittle tectonic overprint is shown to be the principal parameter regulating inflow rate and dominates over depth and lithology. The highest early time inflow rate is 1,300l/s and has been reported from a shallow hydropower gallery intersecting a 200-m wide cataclastic fault zone. The derived lognormal transmissivity distribution is based on 1,361 tunnel intervals with a length of 100m. Such interval transmissivities range between 10−9 and 10−1m2/s within the first 200-400m of depth and between 10−9 and 10−4m2/s in the depth interval of 400-1,500m below ground surface. Outside brittle fault zones, a trend of decreasing transmissivity/hydraulic conductivity with increasing depth is observed for some schistous and gneissic geological units, whereas no trend is identified for the granitic unit

    Unloading joints in the central Aar granite of the Schöllenen Gorge (canton Uri, Switzerland)

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    Zusammenfassung: TalklĂŒfte können im Zusammenhang mit Strasseneinschnitten, Wasserkraftanlagen und geologischen Massenbewegungen in steilen Talflanken eine wichtige Rolle spielen. Die Schöllenenschlucht im Reusstal (zentrale Schweizer Alpen) bildet ein ideales Untersuchungsgebiet fĂŒr das Studium der Eigenschaften und Entstehungsmechanismen solcher TalklĂŒfte. Die Schöllenen- Schlucht liegt am SĂŒdrand des Zentralen Aaregranits, welcher vor rund 300Mio. Jahren intrudierte, wĂ€hrend der Alpenbildung nur lokal duktil deformiert und anschliessend an die OberflĂ€che gehoben wurde. Die bis zu 600 m tiefe Schlucht bietet einen idealen Einblick in das komplexe TrennflĂ€chengefĂŒge des Plutons. Einen Einblick in das Berginnere erlauben zudem die Stollen des Kraftwerks Göschenen. Die Kartierungsarbeit fĂŒhrte zur Unterscheidung von zwei vermutlich alpin-syntektonischen Kluftfamilien (S- und Q-KlĂŒfte) sowie drei Generationen von EntlastungsklĂŒften (subhorizontale DehnungsklĂŒfte (L-KlĂŒfte) und zwei Generationen von mittelsteilen bis steilen TalklĂŒften (T1- und T2- KlĂŒfte)). Die zahlreichen S-KlĂŒfte verlaufen meistens parallel zur alpinen Schieferung, d. h. ungefĂ€hr E-W streichend und steil gegen SĂŒden einfallend. Die weniger hĂ€ufigen Q-KlĂŒfte fallen steil gegen SW ein, der Winkel zwischen den beiden Kluftfamilien betrĂ€gt 60 bis 80 Grad. Die rĂ€umliche Lage der verschiedenen EntlastungsklĂŒfte wurde primĂ€r in Querprofilen durch die Schöllenen erfasst. Die ersten EntlastungsklĂŒfte verlaufen horizontal, sie bildeten sich unabhĂ€ngig von der Topographie möglicherweise wĂ€hrend einer spĂ€talpinen miocĂ€nen Hebung des Aarmassivs. Eine erste Generation von TalklĂŒften (T1) fĂ€llt mit 30-45 Grad beidseitig talwĂ€rts ein und wurde vermutlich wĂ€hrend einer frĂŒhen pleistozĂ€nen Eintalung gebildet. Die jĂŒngsten TalklĂŒfte (T2) sind parallel zur heutigen TaloberflĂ€che der Schöllenenschlucht orientiert, d. h. sie liegen parallel zu den mit spĂ€tpleistozĂ€nen Gletscherschliffen markierten FelsoberflĂ€chen. Die Frequenz sowie die Grösse dieser KlĂŒfte nehmen zumindest in einem Stollen gegen das Berginnere ab und konnten bis rund 150 Meter ins Berginnere nachgewiesen werden. Fraktographische Untersuchungen, d. h. die Untersuchung von Bruchstrukturen auf KluftoberflĂ€chen (hauptsĂ€chlich Federmarken mit einer Grösse von 5 bis 10 m) bestĂ€tigten diese relative Alterabfolge. Ebenso konnten dadurch jeweils der Ursprungspunkt einer Kluft und die Bruchfortpflanzungsrichtung bestimmt werden. Es zeigte sich dabei stets, dass grosse TalklĂŒfte (bis ĂŒber hundert Meter LĂ€nge) aus mehreren 5-10 Meter grossen ExtensionsklĂŒften bestehen, welche durch primĂ€r subhorizontale stabile Rissausbreitung entstanden sind. Grosse TalklĂŒfte bilden sich bevorzugt in Graniten mit nur geringer alpin-tektonischer ĂŒberprĂ€gung. Die TalklĂŒfte der Schöllenen bilden sich nicht als ScherbrĂŒche, wie dies von frĂŒheren Autoren angenommen wurde, sondern als Extensionsrisse in einem kompressiven Spannungsfeld. Das rĂ€umliche Auftreten und die beobachteten Grössen der TalklĂŒfte können teilweise mit quantitativen Bruchkriterien, wie sie fĂŒr hohlraumnahe Extensionsrisse in Tunnelwerken entwickelt wurden, erklĂ€rt werden. Wesentlich fĂŒr den Ort und die Grösse der TalklĂŒfte sind neben den Deviatorspannungen und Zugspannungen auch die σ3/σ1 HauptspannungsverhĂ€ltnisse. Erste numerische Modellrechnungen zu einer mehrphasigen glazialen Eintalung vermögen die beobachteten Bildungsbereiche und Eigenschaften der TalklĂŒfte grob abzubilde

    Reversible rock-slope deformations caused by cyclic water-table fluctuations in mountain slopes of the Central Alps, Switzerland

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    Within the framework of the Gotthard Base Tunnel Project in the Central Alps, Switzerland, geodetic monitoring networks were installed above the tunnel trajectory in alpine valleys. Natural ground-surface deformation recorded in the years prior to the tunneling excavation was seen to contain an unexpectedly large cyclical component of horizontal strain across the valleys, which was seasonal and appeared to be due to elastic processes. The strain is strongly correlated with snow melt and rainstorm precipitation, suggesting the implied rock-mass deformation is driven by changes in water-table elevation within adjacent mountain slopes. The horizontal strains are of the order of 1-2·10-5, which is close to the design limits that can be accommodated by hydropower arch dams in the study area. This study investigates these processes in detail and describes a new mathematical model (REROD), which is able to accurately reproduce and predict such natural rock-slope displacements. The model implements a transfer-function approach to predict the valley-crossing strains from rainfall and winter snow height data recorded at nearby meteorological stations. It has been used to estimate and remove the natural strain signal from the net recorded deformation so as to resolve the component due to tunnelin

    Structure, geometry and formation of brittle discontinuities in anisotropic crystalline rocks of the Central Gotthard Massif, Switzerland

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    Abstract.: Spatial occurrence, structural architecture and formation of brittle fault zones and joints are investigated by outcrop observations, scanline mapping, and light- and scanning electron microscopy in an anisotropic crystalline rock mass (e.g. granites, para-gneisses and schists) of the central Gotthard massif in the Swiss Alps. The analysis presented illustrates that several pre-fault anisotropic features (i.e. dykes, ductile shear zones, foliation and presumably a pre-existing meso-scale fracture set) control the nucleation and propagation of brittle faults. Three sets of brittle fault zones striking NE-SW, NNE-SSW and WNWESE can be distinguished. They formed through cataclasis at temperatures below 300°C, and were activated predominately in a strike-slip regime. Up to five joint sets were mapped and characterized according to orientation, frequency, spacing and formation. Finally a regional fan structure was established in the Gotthard Pass area, encompassing the main foliation, steeply dipping joints and brittle fault zones, each of which shows the same orientation and location of the symmetry plane (NE-SW orientated

    NightShift: NMR shift inference by general hybrid model training - a framework for NMR chemical shift prediction

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    BACKGROUND: NMR chemical shift prediction plays an important role in various applications in computational biology. Among others, structure determination, structure optimization, and the scoring of docking results can profit from efficient and accurate chemical shift estimation from a three-dimensional model. A variety of NMR chemical shift prediction approaches have been presented in the past, but nearly all of these rely on laborious manual data set preparation and the training itself is not automatized, making retraining the model, e.g., if new data is made available, or testing new models a time-consuming manual chore. RESULTS: In this work, we present the framework NightShift (NMR Shift Inference by General Hybrid Model Training), which enables automated data set generation as well as model training and evaluation of protein NMR chemical shift prediction. In addition to this main result – the NightShift framework itself – we describe the resulting, automatically generated, data set and, as a proof-of-concept, a random forest model called Spinster that was built using the pipeline. CONCLUSION: By demonstrating that the performance of the automatically generated predictors is at least en par with the state of the art, we conclude that automated data set and predictor generation is well-suited for the design of NMR chemical shift estimators. The framework can be downloaded from https://bitbucket.org/akdehof/nightshift. It requires the open source Biochemical Algorithms Library (BALL), and is available under the conditions of the GNU Lesser General Public License (LGPL). We additionally offer a browser-based user interface to our NightShift instance employing the Galaxy framework via https://ballaxy.bioinf.uni-sb.de/

    ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP

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    A community diagnostics and performance metrics tool for the evaluation of Earth system models (ESMs) has been developed that allows for routine comparison of single or multiple models, either against predecessor versions or against observations. The priority of the effort so far has been to target specific scientific themes focusing on selected essential climate variables (ECVs), a range of known systematic biases common to ESMs, such as coupled tropical climate variability, monsoons, Southern Ocean processes, continental dry biases, and soil hydrology–climate interactions, as well as atmospheric CO2 budgets, tropospheric and stratospheric ozone, and tropospheric aerosols. The tool is being developed in such a way that additional analyses can easily be added. A set of standard namelists for each scientific topic reproduces specific sets of diagnostics or performance metrics that have demonstrated their importance in ESM evaluation in the peer-reviewed literature. The Earth System Model Evaluation Tool (ESMValTool) is a community effort open to both users and developers encouraging open exchange of diagnostic source code and evaluation results from the Coupled Model Intercomparison Project (CMIP) ensemble. This will facilitate and improve ESM evaluation beyond the state-of-the-art and aims at supporting such activities within CMIP and at individual modelling centres. Ultimately, we envisage running the ESMValTool alongside the Earth System Grid Federation (ESGF) as part of a more routine evaluation of CMIP model simulations while utilizing observations available in standard formats (obs4MIPs) or provided by the user

    Simulation-based cheminformatic analysis of organelle-targeted molecules: lysosomotropic monobasic amines

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    Cell-based molecular transport simulations are being developed to facilitate exploratory cheminformatic analysis of virtual libraries of small drug-like molecules. For this purpose, mathematical models of single cells are built from equations capturing the transport of small molecules across membranes. In turn, physicochemical properties of small molecules can be used as input to simulate intracellular drug distribution, through time. Here, with mathematical equations and biological parameters adjusted so as to mimic a leukocyte in the blood, simulations were performed to analyze steady state, relative accumulation of small molecules in lysosomes, mitochondria, and cytosol of this target cell, in the presence of a homogenous extracellular drug concentration. Similarly, with equations and parameters set to mimic an intestinal epithelial cell, simulations were also performed to analyze steady state, relative distribution and transcellular permeability in this non-target cell, in the presence of an apical-to-basolateral concentration gradient. With a test set of ninety-nine monobasic amines gathered from the scientific literature, simulation results helped analyze relationships between the chemical diversity of these molecules and their intracellular distributions

    A roadmap for high-resolution satellite soil moisture applications – confronting product characteristics with user requirements

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    Soil moisture observations are of broad scientific interest and practical value for a wide range of applications. The scientific community has made significant progress in estimating soil moisture from satellite-based Earth observation data, particularly in operationalizing coarse-resolution (25-50 km) soil moisture products. This review summarizes existing applications of satellite-derived soil moisture products and identifies gaps between the characteristics of currently available soil moisture products and the application requirements from various disciplines. We discuss the efforts devoted to the generation of high-resolution soil moisture products from satellite Synthetic Aperture Radar (SAR) data such as Sentinel-1 C-band backscatter observations and/or through downscaling of existing coarse-resolution microwave soil moisture products. Open issues and future opportunities of satellite-derived soil moisture are discussed, providing guidance for further development of operational soil moisture products and bridging the gap between the soil moisture user and supplier communities

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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