Numerical Representation of Groundwater-Surface Water Exchange and the Effect on Streamflow Contribution Estimates

The effects of streams and drainage representation in 3D numerical catchment scale models on estimated streamflow contribution were investigated. MODFLOW-USG was used to represent complex geology and a stream network with two different conceptualizations—one with equal cell discretization in the entire model domain and another with refined cell discretization along stream reaches. Both models were calibrated against a large data set including hydraulic heads and streamflow measurements. Though the optimized hydraulic parameters and statistical performance of both model conceptualizations were comparable, their estimated streamflow contribution differed substantially. In the conceptualization with equal cell discretization, the drainage contribution to the streamflow was 13% compared to 41% in the conceptualization with refined cell discretization. The increase in drainage contribution to streamflow was attributed to the increase in drainage area in proximity to the stream reaches arising from the refined discretization. e.g., the cell refinement along stream reaches reduced the area occupied by stream cells allowing for increased drain area adjacent to the stream reaches. As such, an increase in drainage area equivalent to 7% yielded a 146% increase in drainage contribution to streamflow. In-stream field measurements of groundwater-surface water exchange fluxes that were qualitatively compared to calculated fluxes from the models indicated that estimates from the refined model discretization were more representative. Hence, the results of this study accentuate the importance of being able to represent stream and drain flow contribution correctly, that is, to achieve representative exchange fluxes that are crucial in simulating groundwater–surface water exchange of both flow and solute transport in catchment scale modeling. To that end, the in-stream measurements of exchange fluxes showed the potential to serve as a proxy to numerically estimate drainage contribution that is not readily available at the catchment scale.

LKB1 coordinates neurite remodeling to drive synapse layer emergence in the outer retina

Structural changes in pre and postsynaptic neurons that accompany synapse formation often temporally and spatially overlap. Thus, it has been difficult to resolve which processes drive patterned connectivity. To overcome this, we use the laminated outer murine retina. We identify the serine/threonine kinase LKB1 as a key driver of synapse layer emergence. The absence of LKB1 in the retina caused a marked mislocalization and delay in synapse layer formation. In parallel, LKB1 modulated postsynaptic horizontal cell refinement and presynaptic photoreceptor axon growth. Mislocalized horizontal cell processes contacted aberrant cone axons in LKB1 mutants. These defects coincided with altered synapse protein organization, and horizontal cell neurites were misdirected to ectopic synapse protein regions. Together, these data suggest that LKB1 instructs the timing and location of connectivity in the outer retina via coordinate regulation of pre and postsynaptic neuron structure and the localization of synapse-associated proteins.

Synchysite-(Ce) from Cinquevalli (Trento, Italy): Stacking Disorder and the Polytypism of (Ca,REE)-Fluorcarbonates

Synchysite-(Ce) at Cinquevalli occurs as fine needles intergrown with quartz in quartz-dikes and in association with altered K-feldspar and oxidized chalcopyrite as major constituents. Synchysite-(Ce) [Ca1.00(Ce0.43La0.26Nd0.17Y0.07Pr0.04Sm0.02Gd0.01)Σ=1.00(CO3)2(F0.58(OH)0.42)], shows an overgrowth rim of bastnäsite-(Ce) [(Ce0.34La0.25Nd0.17Pb0.07C a0.06Y0.06Pr0.04S m0.02Gd0.01)Σ=1.00C O3(F0.75(OH)0.25)]. Unit cell refinement of synchysite (C2/c) and bastnäsite (P62c) led to a = 12.272(4), b = 7.100(2), c = 18.640(5) Å, β = 102.71(5)°, and a = 7.085(1), c = 9.746(2) Å, respectively. Polysomatic faults are sporadic, but polytypic disorder is widespread. High resolution transmission electron microscopy images taken along [100] or ⟨130⟩ show an apparent order and the related diffraction patterns are streak-free. Conversely, along [010] or ⟨110⟩, a high density of stacking faults is observed and the related diffraction patterns show hhl rows with h ≠ 3n affected by streaks. No ordered domain larger than a few unit cells was detected. The stacking sequence of (Ca,REE)-fluorcarbonates can be compared with subfamily-B mica polytypes (2M2, 2O and 6H), which are characterized by n·60° (n = odd) rotations. Subfamily-A polytypes (1M, 2M1 and 3T), characterized by n·60° (n = even) rotations, should not be possible. Synchysite, characterized by ±60° rotations, can be likened to the 2M2 polytype.

Cell refinement of CsPbBr3 perovskite nanoparticles and thin films

In this work, we performed a detailed study of the phase transformations and structural unit cell parameters of CsPbBr3 nanoparticles (NPs) and thin films.

Nirtetralin inhibits growth of hepatitis E virus in HepaRG™ cells

<p>Among numerous established in human hepatoma cell lines, none has been shown susceptible to hepatitis E virus (HEV) infection. Differentiation and infect ability are maintained but when these cells are cultured in the presence of corticoids and dimethyl sulfoxide. On exposure to the nirtetralin, the virion particles were found to be decreased with an IC₅₀ of 2.277. Quantitative analysis of total and closed circular HEV RNA by real-time PCR performed on five independent experiments showed that only 1-5% of the HEV RNA internalized at day 1 post-infection entered the core of the cell refinement. The knockdown of 4E-BP1 led to a 1.7 ± 0.6-fold (mean ± SD, n = 5, p&lt;0.01) and 2.4 ± 0.9-fold (mean ± SD, n = 4, p&lt;0.05) (by the clone 56) growth of HEV RNA, respectively. Duncan's multiple range tests were applied to compare the differences between the treatment groups.</p><p> </p>

New statistical calibration approach for Bruker AXS D8 Discover microdiffractometer with Hi-Star detector using GADDS software

An additional statistical calibration for the Bruker D8 Discover microdiffractometer is necessary to obtain accurate reproducible 2θ data for cell-refinement work. This new approach uses a graphical mapping method of the 2θ error versus the location of a selected diffraction peak on the detector surface to describe the separate roles of different calibration procedures (rebiasing, flood field, and spatial corrections) and parameters (sample-to-detector distance, x-y center coordinate) in minimizing the error. Optimized parameters are used to obtain the lowest achievable Δ2θ with this setup. Intensity error relative to the position of the diffracted line on the detector was found to be consistent at up to 20% and could not be reduced using any of the investigated techniques and parameters.

X-Ray Diffraction Analysis and Magnetic Properties of Pr-Fe-B HDDR Powders and Magnets

Fine magnetic powder has been produced using the hydrogenation disproportionation desorption and recombination (HDDR) process. The first goal of this work involved an investigation of a range of disproportionation/desorption temperatures between 800 and 900°C with the purpose of optimizing the HDDR treatment for a Pr14Fe80B6 alloy. The cast alloy was annealed at 1100°C for 20 hours for homogenization. The optimum disproportionation temperature for achieving high anisotropy was 820°C. The influence of the reaction temperature on the microstructure and magnetic properties of Pr14Fe80B6 HDDR powders and magnets has been shown. A second stage of this study involved the characterization, for each temperature, of the HDDR processed powder using X-ray diffraction analysis. Samples of the HDDR material have been studied by synchrotron radiation powder diffraction using the Rietveld method for cell refinement, phase quantification and crystallite sizes determination. Scanning electron microscopy (SEM) has also been employed to reveal the morphology of the HDDR powder.

Parametric Finite-Volume Micromechanics of Uniaxial Continuously-Reinforced Periodic Materials With Elastic Phases

The finite-volume direct averaging micromechanics (FVDAM) theory for periodic heterogeneous materials is extended by incorporating parametric mapping into the theory’s analytical framework. The parametric mapping enables modeling of heterogeneous microstructures using quadrilateral subvolume discretization, in contrast with the standard version based on rectangular subdomains. Thus arbitrarily shaped inclusions or porosities can be efficiently rendered without the artificially induced stress concentrations at fiber/matrix interfaces caused by staircase approximations of curved boundaries. Relatively coarse unit cell discretizations yield effective moduli with comparable accuracy of the finite-element method. The local stress fields require greater, but not exceedingly fine, unit cell refinement to generate results comparable with exact elasticity solutions. The FVDAM theory’s parametric formulation produces a paradigm shift in the continuing evolution of this approach, enabling high-resolution simulation of local fields with much greater efficiency and confidence than the standard theory.