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An analysis of recorded and simulated SH wave reverberations in the upper mantle beneath the USArray
- Creator:
- Meichen Liu
- Description:
- We use waveform data from the USArray and spectral-element method synthetics for 3-D seismic models. The recorded waveform data are downloaded from Incorporated Research Institutions for Seismology (IRIS) which is open to everyone. The synthetic waveform data are generated by the SPECMFEM3D_Globe software that was downloaded from the Computational Infrastructure for Geodynamics ( https://geodynamics.org/). This dataset includes the scripts we use to automatically download data from IRIS, the selection of data, and the application of the CRP method. In doing this, we use the TauP toolkit which is free to download ( https://www.seis.sc.edu/taup/) to compute the travel time.
- Keyword:
- seismology
- Discipline:
- Science
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- Creator:
- Liu, Meichen
- Description:
- The Brune source model is widely used in studies of complex earthquakes with multiple episodes of high moment release (i.e., multiple subevents). In this study, we investigate how corner frequency estimates of earthquakes with multiple subevents are biased if they are based on the Brune source model. By assuming complex sources as a sum of multiple Brune sources, we analyze 1,640 source time functions (STFs) of Mw 5.5-8.0 earthquakes in the SCARDEC catalog to estimate the corner frequencies, onset times, and seismic moments of subevents. We identify more subevents for strike-slip earthquakes than dip-slip earthquakes, and the number of resolvable subevents increases with magnitude. We find that earthquake corner frequency correlates best with the corner frequency of the subevent with the highest moment release (i.e., the largest subevent). This suggests that, when the Brune model is used, the estimated corner frequency and therefore the stress drop of a complex earthquake is determined primarily by the largest subevent rather than the total rupture area. and Our results imply that the stress variation of asperities, rather than the average stress change of the whole fault, contributes to the large variance of stress drop estimates.
- Citation to related publication:
- Meichen Liu, Yihe Huang, Jeroen Ritsema. 2021. Characterizing Multi-Subevent Earthquakes Using the Brune Source Model [Preprint]. https://essoar.org (2021) DOI: doi.org/10.1002/essoar.10507564.1
- Discipline:
- Science
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- Creator:
- Nunley, Hayden, Nagashima, Mikiko, Martin, Kamirah, Lorenzo Gonzalez, Alcides, Suzuki, Sachihiro C., Norton, Declan A., Wong, Rachel O. L., Raymond, Pamela A., and Lubensky, David K.
- Description:
- This dataset is composed of eight flat-mounted (dissected and fixed) retinae from juvenile and adult zebrafish. Rows of UV cones have been traced in each retina; additionally, we have identified locations of Y-junctions (row insertions). Also included is MATLAB code for calculating which Y-junctions belong to grain boundaries. Please see the readme file for a description of included codes and image files.
- Keyword:
- zebrafish cone mosaic, topological defects, tissue patterning, and grain boundaries
- Citation to related publication:
- Nunley, H., Nagashima, M., Martin, K., Gonzalez, A. L., Suzuki, S. C., Norton, D. A., Wong, R. O. L., Raymond, P. A., & Lubensky, D. K. (2020). Defect patterns on the curved surface of fish retinae suggest a mechanism of cone mosaic formation. PLOS Computational Biology, 16(12), e1008437. https://doi.org/10.1371/journal.pcbi.1008437 and Hayden Nunley, Mikiko Nagashima, Kamirah Martin, Alcides Lorenzo Gonzalez, Sachihiro C. Suzuki, Declan Norton, Rachel O. L. Wong, Pamela A. Raymond, David K. Lubensky. Defect patterns on the curved surface of fish retinae suggest mechanism of cone mosaic formation. bioRxiv 806679; doi: https://doi.org/10.1101/806679
- Discipline:
- Science
-
- Creator:
- Regoli, Leonardo H.
- Description:
- The research analyzed the response of nine PNI RM3100 magnetometers to radiation doses expected during a Europa lander mission. The radiation levels are drawn from the Europa Lander Science Definition Team report ( https://europa.nasa.gov/resources/58/europa-lander-study-2016-report). The sensors were tested up to a total ionization dose (TID) level of 500 kRad.
- Keyword:
- Magnetometer, Magneto-inductive, Europa, and Radiation
- Citation to related publication:
- Regoli, L. H., Moldwin, M. B., Raines, C., Nordheim, T. A., Miller, C. A., Carts, M., and Pozzi, S. A.: Radiation tolerance of the PNI RM3100 magnetometer for a Europa lander mission, Geosci. Instrum. Method. Data Syst., 9, 499–507, https://doi.org/10.5194/gi-9-499-2020, 2020.
- Discipline:
- Science and Engineering
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- Creator:
- Sean Sharp
- Description:
- Coastal wetlands intercept significant amounts of nitrogen (N) from watersheds, especially when surrounding land cover is dominated by agriculture and urban development. Through plant uptake, soil immobilization, and denitrification wetlands can remove excess N from flow through water sources and mitigate eutrophication of connected aquatic ecosystems. Excess N can also change plant community composition in wetlands, including communities threatened by invasive species. Understanding how variable hydrology and N loading impact wetland N removal and community composition can help attain desired management outcomes, including optimizing N removal and/or preventing invasion by non-natives. By using a dynamic, process-based ecosystem simulation model, we are able to simulate various levels of hydrology and N loading that would otherwise be difficult to manipulate. We investigate the effects of hydroperiod, hydrologic residence time, N loading, and the NH4+:NO3- ratio on both N removal and the invasion success of two non-native species (Typha x glauca or Phragmites australis) in temperate freshwater coastal wetlands using Mondrian, a process-based, wetland ecosystem simulation model. We found that when residence time increased, annual N removal increased up to 10-fold while longer hydroperiods also increased N removal, but only when residence time was >10 days and N loading was >30 g N m-2 y-1. N removal efficiency also increased with increasing residence time and hydroperiod, but was less affected by N loading. However, longer hydrologic residence time increased vulnerability of wetlands to invasion by both invasive plants at low to medium N loading rates where native communities are typically more resistant to invasion. This suggests a potential tradeoff between ecosystem services related to nitrogen removal and wetland invasibility. These results help elucidate complex interactions of community composition, N loading and hydrology on N removal, helping managers to prioritize N removal when N loading is high or controlling plant invasion in more vulnerable wetlands.
- Keyword:
- Mondrian, Simulation model, Coastal wetlands, Invasive species, and Ecosystem modeling
- Citation to related publication:
- Currie, W. S., Goldberg, D. E., Martina, J., Wildova, R., Farrer, E., & Elgersma, K. J. (2014). Emergence of nutrient-cycling feedbacks related to plant size and invasion success in a wetland community–ecosystem model. Ecological Modelling, 282, 69–82. https://doi.org/10.1016/j.ecolmodel.2014.01.010
- Discipline:
- Science
-
- Creator:
- BIRDS Lab, U. Michigan
- Description:
- These data were produced for ARO W911NF-14-1-0573 "Morphologically Modulated Dynamics" and ARO MURI W911NF-17-1-0306 "From Data-Driven Operator Theoretic Schemes to Prediction, Inference, and Control of Systems" to explore the trade-offs between various oscillator coupling models in modeling multilegged locomotion of Multipod robots with 6,8,10 and 12 legs. The data is stored in .csv.gz files, one file for each robot morphology. Details of how to run the processing code on the raw dataset to generate the processed files found here, as well as example code for loading the data found here, are in the README. This dataset is self contained and can be used on its own without running any of the provided code.
- Citation to related publication:
- Zhao, D. & Revzen, S. Multi-legged steering and slipping with low DoF hexapod robots Bioinspiration & biomimetics, 2020, 15, 045001 https://doi.org/10.1088/1748-3190/ab84c0, Zhao, D. Ph.D. Thesis "Locomotion of low-DOF multi-legged robots" University of Michigan 2021 https://deepblue.lib.umich.edu/handle/2027.42/169985, and BIRDS Lab Multipod robot motion tracking data - RAW data, doi:10.7302/m05a-0d90
- Discipline:
- Engineering and Science
-
- Creator:
- Agnit Mukhopadhyay
- Description:
- - A semi-physical global modeling approach is used to estimate diffuse & discrete sources of auroral precipitation during the Galaxy15 event. - Diffuse sources contribute 74% of the total auroral power. Discrete sources are strongly driven by activity and can contribute up to 61%. - Broadband precipitation contributes 31% of the auroral Pedersen conductance playing a significant role in ionospheric electrodynamics.
- Discipline:
- Science and Engineering
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Dataset: Models generated for the bioinformatic analysis of MPER/protein fusions binding to antibody
- Creator:
- Bylund, Tatsiana, Chuang, Gwo-Yu, Kwong, Peter, Lai, Yen-Ting, McIlwain, Benjamin, and Stockbridge, Randy B.
- Description:
- This project evaluated the binding of antibody fragments to membrane proteins fused to a short epitope sequence (“MPER”). This dataset includes atomic coordinates (.pdb files) for bioinformatic models of antibody fragment binding to an MPER epitope – membrane protein fusion.
- Keyword:
- MPER, cryo-EM fiducial, crystallography chaperone, and small membrane protein
- Citation to related publication:
- McIlwain, B. C., Erwin, A. L., Davis, A. R., Ben Koff, B., Chang, L., Bylund, T., Chuang, G.-Y., Kwong, P. D., Ohi, M. D., Lai, Y.-T., & Stockbridge, R. B. (2021). N-terminal Transmembrane-Helix Epitope Tag for X-ray Crystallography and Electron Microscopy of Small Membrane Proteins. Journal of Molecular Biology, 166909. https://doi.org/10.1016/j.jmb.2021.166909
- Discipline:
- Science
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- Creator:
- Malhotra, Garima and Ridley, Aaron
- Description:
- This research aims to understand the importance of lower thermospheric atomic oxygen on the upper thermosphere. O number densities between 95-100 km from WACCM-X are much closer to the observations from SABER instrument on TIMED satellite as compared to those from MSIS. We show in this study that the correction of the lower boundary atomic oxygen yields better agreement between GITM and GUVI O/N2 in the upper thermosphere .
- Keyword:
- Lower Thermosphere Atomic Oxygen, Thermospheric Dynamics, Thermospheric composition and mixing, Lower-Upper Thermosphere Vertical Coupling, GITM - WACCMX coupling, and Global Ionosphere Thermosphere Model
- Citation to related publication:
- Malhotra, G., Ridley, A. J., Marsh, D. R., Wu, C., Paxton, L. J., & Mlynczak, M. G. (2020). Impacts of Lower Thermospheric Atomic Oxygen on Thermospheric Dynamics and Composition Using the Global Ionosphere Thermosphere Model. Journal of Geophysical Research: Space Physics, e2020JA027877. https://doi.org/10.1029/2020JA027877
- Discipline:
- Science
-
- Creator:
- Niemi, Nathan A. and Abbey, Alyssa L.
- Description:
- These data were produced in the scope of research into the timing, rate, and magnitude of extensional exhumation along the length of the Rio Grande Rift in Colorado and New Mexico. The low-temperature (apatite and zircon (U-Th)/He) thermochronometric ages presented in this data set are sensitive to near-surface temperatures (~80C and 180C, respectively) and record the progressive exhumation of the rock mass from which the samples were collected towards the Earth's surface. These thermochronometric ages, and the differences between them, provide insight into the absolute timing, exhumation rate and total magnitude of exhumation on the normal faults that bound the Rio Grande Rift. and The QTQt program mentioned (Version QTQt64R5.6.2a was used for the data presented in this deposit) is not openly available for download, but is described in the Gallagher 2012 publication referenced, and can be requested from its author. For more information on the request process and a user guide, see http://www.iearth.org.au/codes/QTQt/
- Keyword:
- thermochronology, helium dating, (U-Th)/He, Rio Grande Rift, New Mexico, Colorado, and extensional tectonics
- Citation to related publication:
- Abbey, A. L., & Niemi, N. A. (2020). Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA. Tectonics, 39(1), e2019TC005635. https://doi.org/10.1029/2019TC005635
- Discipline:
- Science