Lia Corrales

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My PhD research focused on identifying the size and mineralogical composition of interstellar dust through X-ray imaging of dust scattering halos to X-ray spectroscopy of bright objects to study absorption from intervening material. Over the course of my PhD I also developed an open source, object oriented approach to computing extinction properties of particles in Python that allows the user to change the scattering physics models and composition properties of dust grains very easily. In many cases, the signal I look for from interstellar dust requires evaluating the observational data on the 1-5% level. This has required me to develop a deep understanding of both the instrument and the counting statistics (because modern-day X-ray instruments are photon counting tools). My expertise led me to a postdoc at MIT, where I developed techniques to obtain high resolution X-ray spectra from low surface brightness (high background) sources imaged with the Chandra X-ray Observatory High Energy Transmission Grating Spectrometer. I pioneered these techniques in order to extract and analyze the high resolution spectrum of Sgr A*, our Galaxy’s central supermassive black hole (SMBH), producing a legacy dataset with a precision that will not be replaceable for decades. This dataset will be used to understand why Sgr A* is anomalously inactive, giving us clues to the connection between SMBH activity and galactic evolution. In order to publish the work, I developed an open source software package, pyXsis (github.com/eblur/pyxsis) in order to model the low signal-to-noise spectrum of Sgr A* simultaneously with a non-physical parameteric model of the background spectrum (Corrales et al., 2020). As a result of my vocal advocacy for Python compatible software tools and a modular approach to X-ray data analysis, I became Chair for HEACIT (which stands for “High Energy Astrophysics Codes, Interfaces, and Tools”), a new self-appointed working group of X-ray software engineers and early career scientists interested in developing tools for future X-ray observatories. We are working to identify science cases that high energy astronomers find difficult to support with the current software libraries, provide a central and publicly available online forum for tutorials and discussion of current software libraries, and develop a set of best practices for X-ray data analysis. My research focus is now turning to exoplanet atmospheres, where I hope to measure absorption from molecules and aerosols in the UV. Utilizing UM access to the Neil Gehrels Swift Observatory, I work to observe the dip in a star’s brightness caused by occultation (transit) from a foreground planet. Transit depths are typically <1%, and telescopes like Swift were not originally designed with transit measurements (i.e., this level of precision) in mind. As a result, this research strongly depends on robust methods of scientific inference from noisy datasets.

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As a graduate student, I attended some of the early “Python in Astronomy” workshops. While there, I wrote Jupyter Notebook tutorials that helped launch the Astropy Tutorials project (github.com/astropy/astropy-tutorials), which expanded to Learn Astropy (learn.astropy.org), for which I am a lead developer. Since then, I have also become a leader within the larger Astropy collaboration. I have helped develop the Astropy Project governance structure, hired maintainers, organized workshops, and maintained an AAS presence for the Astropy Project and NumFocus (the non-profit umbrella organization that works to sustain open source software communities in scientific computing) for the last several years. As a woman of color in a STEM field, I work to clear a path by teaching the skills I have learned along the way to other underrepresented groups in STEM. This year I piloted WoCCode (Women of Color Code), an online network and webinar series for women from minoritized backgrounds to share expertise and support each other in contributing to open source software communities.

Ayumi Fujisaki-Manome

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Fujisaki-Manome’s research program aims to improve predictability of hazardous weather, ice, and lake/ocean events in cold regions in order to support preparedness and resilience in coastal communities, as well as improve the usability of their forecast products by working with stakeholders. The main question Fujisaki-Manome’s research aims to address is: what are the impacts of interactions between ice and oceans / ice and lakes on larger scale phenomena, such as climate, weather, storm surges, and sea/lake ice melting? Fujisaki-Manome primarily uses numerical geophysical modeling and machine learning to address the research question; and scientific findings from the research feed back into the models and improve their predictability. Her work has focused on applications to the Great Lakes, the Alaska’s coasts, Arctic Ocean, and the Sea of Okhotsk.

View MIDAS Faculty Research Pitch, Fall 2021

Areal fraction of ice cover in the Great Lakes in January 2018 modeled by the unstructured grid ice-hydrodynamic numerical model.

Jesse Hamilton

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My research focuses on the development of novel Magnetic Resonance Imaging (MRI) technology for imaging the heart. We focus in particular on quantitative imaging techniques, in which the signal intensity at each pixel in an image represents a measurement of an inherent property of a tissue. Much of our research is based on cardiac Magnetic Resonance Fingerprinting (MRF), which is a class of methods for simultaneously measuring multiple tissue properties from one rapid acquisition.

Our group is exploring novel ways to combine physics-based modeling of MRI scans with deep learning algorithms for several purposes. First, we are exploring the use of deep learning to design quantitative MRI scans with improved accuracy and precision. Second, we are developing deep learning approaches for image reconstruction that will allow us to reduce image noise, improve spatial resolution and volumetric coverage, and enable highly accelerated acquisitions to shorten scan times. Third, we are exploring ways of using artificial intelligence to derive physiological motion signals directly from MRI data to enable continuous scanning that is robust to cardiac and breathing motion. In general, we focus on algorithms that are either self-supervised or use training data generated in computer simulations, since the collection of large amounts of training data from human subjects is often impractical when designing novel imaging methods.

Xianglei Huang

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Prof. Huang is specialized in satellite remote sensing, atmospheric radiation, and climate modeling. Optimization, pattern analysis, and dimensional reduction are extensively used in his research for explaining observed spectrally resolved infrared spectra, estimating geophysical parameters from such hyperspectral observations, and deducing human influence on the climate in the presence of natural variability of the climate system. His group has also developed a deep-learning model to make a data-driven solar forecast model for use in the renewable energy sector.

Tamas Gombosi

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Tamas Gombosi is the Konstantin Gringauz Distinguished University Professor of Space Science and the Gerstacker Professor of Engineering at the University of Michigan.
Over his four-decade-long career at Michigan he participated in a number of space missions (Cassini, Rosetta, Stereo, MMS and others). In the last two decades he has led a highly interdisciplinary team that developed the first solution adaptive (AMR) global magnetohydrodynamic (MHD) simulation code of space plasmas. His most recent research focus is to bring advanced machine learning to space weather modeling.
He is Fellow of the AGU (1996), Member of the International Academy of Astronautics (1997), recipient of AGU’s inaugural Space Weather Prize (2013), Van Allen Lecturer of AGU’s SPA section (2017), recipient of the Kristian Birkeland Medal (2018), and recipient of AGU’s John Adam Fleming Medal (2020).

Robert Ziff

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I study the percolation model, which is the model for long-range connectivity formation in systems that include polymerization, flow in porous media, cell-phone signals, and the spread of diseases. I study this on random graphs and other networks, and on regular lattices in various dimensions, using computer simulation and analysis. We have also worked on developing new algorithms. I am currently applying these methods to studying the COVID-19 pandemic, which also requires comparison with some of the vast amount of data that is available from every part of the world.

 

Nicole Seiberlich

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My research involves developing novel data collection strategies and image reconstruction techniques for Magnetic Resonance Imaging. In order to accelerate data collection, we take advantage of features of MRI data, including sparsity, spatiotemporal correlations, and adherence to underlying physics; each of these properties can be leveraged to reduce the amount of data required to generate an image and thus speed up imaging time. We also seek to understand what image information is essential for radiologists in order to optimize MRI data collection and personalize the imaging protocol for each patient. We deploy machine learning algorithms and optimization techniques in each of these projects. In some of our work, we can generate the data that we need to train and test our algorithms using numerical simulations. In other portions, we seek to utilize clinical images, prospectively collected MRI data, or MRI protocol information in order to refine our techniques.

We seek to develop technologies like cardiac Magnetic Resonance Fingerprinting (cMRF), which can be used to efficiently collect multiple forms of information to distinguish healthy and diseased tissue using MRI. By using rapid methods like cMRF, quantitative data describing disease processes can be gathered quickly, enabling more and sicker patients can be assessed via MRI. These data, collected from many patients over time, can also be used to further refine MRI technologies for the assessment of specific diseases in a tailored, patient-specific manner.

Kenichi Kuroda

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Synthetic polymers have been used as a molecular platform to develop host-defense antimicrobial peptide (AMP) mimics toward the development of “polymer antibiotics” which are effective in killing drug-resistant bacteria. Our research has been centered on the AMP-mimetic design and chemical optimization strategies as well as the biological and biophysical implications of AMP mimicry by synthetic polymers. The AMP-mimetic polymers showed broad-spectrum activity, rapid bactericidal activity, and low propensity for resistance development in bacteria, which represent the hallmarks of AMPs. The polymers form amphipathic conformations capable of membrane disruption upon binding to bacterial membrane, which recapitulates the folding of alpha-helical AMPs. We propose a new perception that AMP-mimetic polymers are an inherently bioactive platform as whole molecules, which mimic more than the side chain functionalities of AMPs. The chemical and structural diversity of polymers will expand the possibilities for new antimicrobial materials including macromolecules and molecular assemblies with tailored activity. This type of synthetic polymers is cost-effective, suitable for large-scale production, and tunable for diverse applications, providing great potential for the development of versatile platforms that can be used as direct therapeutics or attached on surfaces.

Ward B. Manchester

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My research interests concern solar magnetism and magnetic flux transport from the convection zone into the corona, and through the heliosphere.In this context, I have contributed to basic theory and modeling efforts with analytical work and large-scale numerical simulations. The topics that I am particularly interested in are: magnetic flux emergence, magnetohydrodynamic instabilities, coronal mass ejection (CME) initiation, propagation, and CME-driven shocks. Flux emergence was the topic of my Ph.D. thesis research, which demonstrated that the expansion of magnetic fields in a gravitationally stratified atmosphere naturally produces Lorentz forces that drive shear flows. These flows lead to the formation of highly energized coronal magnetic fields, which are observed to be at the epicenter of coronal eruptions. This work provides a fundamental explanation for shear flows, which for decades, have been prescribed as ad hoc boundary conditions in numerical models of CMEs, flares and filament eruptions. While at the University of Michigan, I have advanced this fundamental theory of CME initiation by simulating the eruption of both magnetic arcades and flux ropes by such self-induced shear flows. I conceived and implemented the Gibson-Low flux rope as a way of simulating coronal mass ejections and applied this model to study the the propagation of CMEs from the solar corona through the heliosphere. In doing so, many new aspects of CME interaction with the interplanetary medium were discovered. With coauthors, I demonstrated the model’s capability to predict ICME disturbances at Earth, and advised my student, Meng Jin, in developing data-driven tool, EEGGL, which prescribe the model’s parameters and is now installed at CCMC. I am now working with faculty in the University of Michigan Department of Statistics to apply machine learning to classify and predict flare events and to identify the underlying physical processes.

Three series of plates at times t =50:0, 57.2, and 72.8 illustrating the expansion of the flux rope from the photosphere into the corona. Panels a–f show the x=0 plane, where the direction of the magnetic field (confined to the plane) is depicted with solid white lines. Panels a–c show a color representation of the shear velocity Ux, while panels d–f show color images of the shear angle measured in degrees. Panels g–i show three-dimensional representations of the magnetic field lines, color coded as described in the text. Panels g and i show color images of the vertical field strength Bz at the photosphere. Panel h shows a color image of the shear velocity at the photosphere, along with co-spatial vectors that indicate the magnitude and direction of the flow. Iso-surfaces of Ux are shown colored in blue (-20 km/s) and red (+20km/s). Reference: Astrophysical Journal, 610:588–596, 2004

Dominika Zgid

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Our work is interdisciplinary in nature and we connect three fields, chemistry, physics and materials science. Our goal is to develop theoretical tools that give access to directly experimentally relevant quantities. We develop and apply codes that describe two types of electronic motion (i) weakly correlated electrons originating from the delocalized “wave-like” s- and p-orbitals responsible for many electron correlation effects in molecules and solids that do not contain transition metal atoms (ii) strongly correlated electrons residing in the d- and f-orbitals that remain localized and behave “particle-like” responsible for many very interesting effects in the molecules containing d- and f-electrons (transition metal nano-particles used in catalysis, nano-devices with Kondo resonances and molecules of biological significance – active centers of metalloproteins). The mutual coupling of these two types of electronic motion is challenging to describe and currently only a few theories can properly account for both types of electronic correlation effects simultaneously.

Available research projects in the group involve (1) working on a new theory that is able to treat weakly and strongly correlated electrons in molecules with multiple transition metal centers with applications to molecular magnets and active centers of enzymes (2) developing a theory for weakly correlated electrons that is able to produce reliable values of band gaps in semiconductors and heterostructures used in solar cells industry (3) applying the QM/QM embedding theories developed in our group to catalysis on transition metal-oxide surfaces and (4) applying the embedding formalism to molecular conductance problems in order to include correlation effects.