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- Creator:
- Thomaz, Andréa T. (UMICH) and Knowles, L. Lacey (UMICH)
- Description:
- The eastern coastal basins of Brazil are a series of small and isolated rivers that drain directly into the Atlantic Ocean. During the Pleistocene, sea-level retreat caused by glaciations exposed the continental shelf, resulting in enlarged paleodrainages that connected rivers that are isolated today. Using Geographic Information System (GIS), we infer the distribution of these paleodrainages, and their properties for the east Brazilian coast. Here, we publicly make available the shapefiles that demonstrate the paleodrainage structure along the Brazilian coast during the largest sea-level retreats in the Pleistocene, the riverine vectors during the same period and the coastal line for a drop of -125m in the sea.
- Keyword:
- Paleodrainages, Glaciations, Pleistocene, Brazil, Neotropical, and Sea-level retreat
- Discipline:
- Science
-
- Creator:
- Kort, EA, Gvakharia, A, Smith, ML, and Conley, S
- Description:
- Data is collected from research flights based in West Memphis, Arkansas, covering the Mississippi River Valley. The data file contains all merged flight data from each flight day.
- Keyword:
- Greenhouse gas
- Citation to related publication:
- Gvakharia, A., Kort, E.A., Smith, M.L., Conley, S., 2018. Testing and evaluation of a new airborne system for continuous N2O, CO2, CO, and H2O measurements: the Frequent Calibration High-performance Airborne Observation System (FCHAOS). Atmospheric Measurement Techniques; Katlenburg-Lindau 11, 6059. https://doi.org/10.5194/amt-11-6059-2018
- Discipline:
- Science
-
- Creator:
- Liemohn, Michael W, McCollough, James P, Engel, Miles A, Jordanova, Vania K, and Morley, Steven K
- Description:
- There is a directory tree inside this zipped file. The main directory has the Adobe Illustrator plots of the figures in the paper, Space Weather journal manuscript # 2018SW002067, "Model evaluation guidelines for geomagnetic index predictions" by M. W. Liemohn and coauthors. The three subdirectories have the files for the individual models, the data to which they are compared, and the IDL code used to create the figure plots and metrics calculations. and Date coverage is specific to each model. The RAMSCB model covers January 2005, the WINDMI model all of 2014, and the UPOS model 1.5 solar cycles, from 1 October 2001 through 29 July 2013.
- Keyword:
- space weather, model assessment, time series metrics, and geomagnetic indices
- Discipline:
- Science
-
- Creator:
- R Paul Drake
- Description:
- The specific focus of the project was radiative shocks, which develop when shock waves become so fast and hot that the radiation from the shocked matter dominates the energy transport. This in turn leads to changes in the shock structure. Radiative shocks are challenging to simulate, as they include phenomena on a range of spatial and temporal scales and involve two types of nonlinear physics Ð- hydrodynamics and radiation transport. Even so, the range of physics involved is narrow enough that one can hope to model all of it with sufficient fidelity to reproduce the data. CRASH was focused on developing predictions for a sequence of experiments performed in Project Year 5, in which those experiments represented an extrapolation from all previously available data. The previous data involved driving radiative shocks within cylindrical structures, and mainly straight tubes. The Year 5 experiments drove a radiative shock down an elliptical tube. Our long-stated goal for these predictions was that the distribution of predicted values would overlap significantly with the observed distribution. We achieved this goal. Achieving our goal required the conversion of an established space-weather code to model radiative shocks at high energy density. To obtain reasonable fidelity with respect to the experimental data required implementing a laser absorption package, in addition to a hydrodynamic solver, electron physics and heat conduction, and multigroup diffusive radiation transport. The dedicated experiments provided evidence of experimental variability, validation of the calculation of initial shock wave behavior, and validation data at many observation times using cylindrical shock tubes. Following this were preparatory experiments for and finally the execution of the Year 5 experiments. The predictive science research included a wide range of sensitivity studies to determine which variables were important and a sequence of predictive studies focused on specific issues and sets of data. This led ultimately to predictions of shock location for the Year 5 experiments. A conclusion from this project is that the serious quantification of uncertainty in simulations is a dauntingly difficult and expensive prospect. Pre-existing codes are unlikely to have been built with attention to what will be needed to quantify their uncertainty. Pre-existing experimental results are even more unlikely to include a sufficiently detailed analysis of the experimental uncertainties. And this will also be true of most experiments that might be used to validate components of the simulation. The analysis of uncertainty in any one of the physical processes (and related physical constants) is a major effort. And addressing model form uncertainty is an even bigger challenge, that may in principle require development of complete, alternative simulation models. We made a start at all of this, and completed almost none of it. But by the end of a project, we finally had all the pieces in place and working that would have enabled a range of important studies and advances in relatively near-term years. But the sponsor terminated the program after only five years. For most of the participants this was a relatively minor development, although for a few of them it proved to be enormously disruptive. We believe that the cost to the nation, in work that was ready be done but now will not be, was much much larger. The sketch of the target was produced using a drawing program based on the experimental dimensions. The annotated photograph of the target was obtained using a visible-light camera. The colorized radiographs were obtained via backilit-pinhole radiography of a radiative shock propagating down an elliptical tube, at 26 ns after the lasers driving the shock tube fired. The graph showing lines and circles was produced by running many computer models, analyzing their statistical distribution, and measuring actual shock positions in the experiment.
- Keyword:
- Radiative shock
- Discipline:
- Science
-
- Creator:
- Ramasubramani, Vyas
- Description:
- The goal of the work is to elucidate the stability of a complex experimentally observed structure of proteins. We found that supercharged GFP molecules spontaneously assemble into a complex 16-mer structure that we term a protomer, and that under the right conditions an even larger assembly is observed. The protomer structure is very well defined, and we performed simulations to try and understand the mechanics underlying its behavior. In particular, we focused on understanding the role of electrostatics in this system and how varying salt concentrations would alter the stability of the structure, with the ultimate goal of predicting the effects of various mutations on the stability of the structure. There are two separate projects included in this repository, but the two are closely linked. One, the candidate_structures folder, contains the atomistic outputs used to generate coarse-grained configurations. The actual coarse-grained simulations are in the rigid_protein folder, which pulls the atomistic coordinates from the other folder. All data is managed by signac and lives in the workspace directories, which contain various folders corresponding to different parameter combinations. The parameters associated with a given folder are stored in the signac_statepoint.json files within each subdirectory. The atomistic data uses experimentally determined protein structures as a starting point; all of these are stored in the ConfigFiles folder. The primary output is the topology files generated from the PDBs by GROMACS; these topologies are then used to parametrize the Monte Carlo simulations. In some cases, atomistic simulations were actually run as well, and the outputs are stored alongside the topology files. In the rigid_protein folder, the ConfigFiles folder contains MSMS, the software used to generate polyhedral representations of proteins from the PDBs in the candidate_structures folder. All of the actual polyhedral structures are also stored in the ConfigFiles folder. The actual simulation trajectories are stored as general simulation data (GSD) files within each subdirectory of the workspace, along with a single .pos file that contains the shape definition of the (nonconvex) polyhedron used to represent a protein. The logged quantities, such as energies and MC move sizes, are stored in .log files. The logic for the simulations in the candidate_structures project is in the Python scripts project.py, operations.py, and scripts/init.py. The rigid_protein folder also includes the notebooks directory, which contains Jupyter notebooks used to perform analyses, as well as the Python scripts used to actually perform the simulations and manage the data space. In particular, the project.py, operations.py and scripts/init.py scripts contain most of the logic associated with the simulations.
- Keyword:
- Protein assembly, Cryo TEM, Hierarchical Assembly, Monte Carlo simulation, and Coarse-grained simulation
- Discipline:
- Science and Engineering
-
- Creator:
- Thomaz, Andréa T. (UMICH), Carvalho, Tiago P. (UFRGS), Malabarba, Luiz R. (UFRGS), and Knowles, L. Lacey (UMICH)
- Description:
- Estimated phylogenetic relationships based on more than 18,000 loci in 93 individuals (full data) or 21 individuals (subset data) representing 19 described species and two putative undescribed species. Nine files are part of this dataset, including all input files to infer the phylogenetic reconstructions and the outputs obtained, in addition to a pruned tree used to infer the ancestral state reconstructions.
- Keyword:
- dusky millions poeciliids, sexual selection, South America, and ddRADseq
- Citation to related publication:
- Andréa T. Thomaz, Tiago P. Carvalho, Luiz R. Malabarba, L. Lacey Knowles, Geographic distributions, phenotypes, and phylogenetic relationships of Phalloceros (Cyprinodontiformes: Poeciliidae): insights about diversification among sympatric species pools, Molecular Phylogenetics and Evolution, 2018, ISSN 1055-7903, https://doi.org/10.1016/j.ympev.2018.12.008
- Discipline:
- Science
-
- Creator:
- Xiantong Wang
- Description:
- We perform a geomagnetic event simulation using a newly developed magnetohydrodynamic with adaptively embedded particle-in-cell (MHD-AEPIC) model. We have developed effective criteria to identify reconnection sites in the magnetotail and cover them with the PIC model. The MHD-AEPIC simulation results are compared with Hall MHD and ideal MHD simulations to study the impacts of kinetic reconnection at multiple physical scales. At the global scale, the three models produce very similar SYM-H and SuperMag Electrojet (SME) indexes, which indicates that the global magnetic field configurations from the three models are very close to each other. At the mesoscale we compare the simulations with in situ Geotail observations in the tail. All three models produce reasonable agreement with the Geotail observations. The MHD-AEPIC and Hall MHD models produce tailward and earthward propagating fluxropes, while the ideal MHD simulation does not generate flux ropes in the near-earth current sheet. At the kinetic scales, the MHD-AEPIC simulation can produce a crescent shape distribution of the electron velocity space at the electron diffusion region which agrees very well with MMS observations near a tail reconnection site. These electron scale kinetic features are not available in either the Hall MHD or ideal MHD models. Overall, the MHD-AEPIC model compares well with observations at all scales, it works robustly, and the computational cost is acceptable due to the adaptive adjustment of the PIC domain.
- Keyword:
- MHD, PIC, and Magnetosphere
- Discipline:
- Science
-
- Creator:
- Holmes, Iris A, Monagan Jr., Ivan V, Westphal, Michael F, and Davis Rabosky, Alison R
- Description:
- We generated these data from desert night lizards, Xantusia vigilis, from populations in central California. We performed phylogeographic analyses based on these data.
- Keyword:
- ddRADseq, phylogeography, Xantusia vigilis, lizard, and genome-scale sequencing
- Discipline:
- Science
-
- Creator:
- Zhang, Yan, Gao, Chuanyu, Zhang, Shaoqing, Yang, Ping, Meyers, Philip A, and Wang, Guoping
- Description:
- The study focuses on reconstructing the histories of peat deposition using n-alkane biomarkers in peat cores and associated modern plant communities from four sites around a shallow maar lake in the Changbai Mountains of northeastern China. Peat development patterns in the four sites are not concordant although the sites experienced the same paleoclimate histories. Evidently, lava flows and tephra deposits produced an uneven topography of the volcanogenic lake basin that controls the water depths at the four lake edge locations, thereby leading to differences in peat-forming plant communities and peat deposition among the four sites.
- Keyword:
- peat deposition, n-alkanes, volcanic eruptions, and Changbai Lake
- Citation to related publication:
- Zhang, Y., Gao, C., Zhang, S., Yang, P., Meyers, P. A., & Wang, G. (2020). N-Alkane-based reconstructions of peat accumulations and depositional conditions at four locations around a shallow maar lake in the Changbai Mountains, northeastern China (world) [Preprint]. Earth and Space Science Open Archive; Earth and Space Science Open Archive. https://doi.org/10.1002/essoar.10505381.1
- Discipline:
- Science
-
- Creator:
- Revzen, Shai
- Description:
- This repository contains both the data and python3 code that reads this data and reproduces the relevant figures. The code depends on NumPy >1.17 and matplotlib >3.1 and was tested on python 3.8
- Keyword:
- locomotion, slipping, low Reynolds number, walking, and slithering
- Discipline:
- Science and Engineering