Exact Science

Where General Relativity, quantum electrodynamics, and plasma physics meet: first-principles models of emission from astrophysical black holes

Eliot Quataert
Benoît Cerutti

Direct observations of hot gas around nearby supermassive black holes on the scale of the hole's event horizon will soon be in reach of the most powerful telescopes. The goal of this collaboration is to develop new numerical tools to perform the first ab-initio model of energetic particles and radiation being produced in the closest environment of a rotating black hole. This work will provide the most direct and self-consistent bridge between rigorous, first-principles simulations and astronomical observations of black holes.


Understanding the structural basis regulating the size and architecture of the mitotic spindle

Rebecca Heald
Denis Chrétien

During cell division a dynamic, bipolar, microtubule polymer-based machine called the mitotic spindle attaches to chromosomes and segregates them to daughter cells. Correct spindle size and shape is essential for its function, but exactly how spindle microtubules are organized and the spatial cues that lead to distinct spindle architectures in different cell types and species is poorly understood. We are taking advantage of a cell-free system based on cytoplasm isolated from frog eggs that reconstitutes spindle assembly in a test tube to analyze the organization and dynamics of spindle...

Understanding energy storage in highly concentrated aqueous salt mixtures

David Limmer
Benjamin Rotenberg

Water metal interfaces have become a topic of renewed interest in the scientific community, due the recent discovery that in the presence of high concentrations of salt, electrochemical devices can be constructed that are stable over a wide range of working conditions. Using recently developed computational tools, we aim to use simulation models to study the molecular properties of highly concentrated salt solutions. By doing so, we hope to understand why these interfaces are so stable, and uncover general design principles for next generation energy storage devices that are both...

New paleogeographic models and the onset of a major glacial event in the Ordovician

Nicholas Swanson-Hyssell
Yves Goddéris

Earth's climate today includes the presence of large polar ice caps, but there have been periods of Earth history with no such glacial ice. This collaborative research seeks to understand the factors that determine Earth's long-term climate state by focusing on a transition from a non-glacial to a glacial climate that occurred 450 million years ago. The research will use updated reconstructions of the past position of the continents in combination with climate and carbon cycle numerical modeling to test the hypothesis that uplift of volcanic rocks within an ancient tropical mountain belt...

Exploring Photocatalytic CO2 Reduction to Fuels with Small Molecular Iron Clusters

Louise Berben
Marc Robert

This project will advance the chemistry of CO2 to fuels conversion using small iron clusters by a collaboration to combine fuels production directly with the harvesting of energy from light. Thus we create a sunlight-to-liquid fuels system for storage of renewable energy. Expertise in iron catalyst development at UC Davis complements expertise in photochemistry at University of Paris-Diderot.

Louise Berben

UC PI:...

Examining the history and impact of gene content variation in sunflower

Benjamin Blackman
Hélène Bergès

Recent progress in plant genomics has revealed that the total functional gene sequence present among all individuals of a species, also known as the pan-genome, is far larger than the content annotated in a single individual's genome. This diversity in gene content arises because large DNA duplication, insertion, or deletion events lead to variation in the presence or absence of whole genes among individuals within species, and this variation may have contributed in the past to crop domestication or adaptation of wild populations to local habitats. The investigators will develop advanced...

Determining the interaction of viruses with autotrophic prokaryotic hosts in soil

Mary Firestone
Graeme Nicol

While we are beginning to understand the complexity of bacterial and archaeal communities in soil, we are currently ignorant of the roles of viruses in influencing the ecology of these soil populations. Infection by lytic viruses is followed by replication and lysis of the host cell, releases new virions into the environment. In addition to controlling population numbers, viral infection also has major consequences for nutrient cycles. We are targeting a critical process in the nitrogen cycle (nitrification) using stable isotope (13C) enabled metagenomic analyses.


Combining genome-resolved metagenomics and phylogenomics approaches to unravel the diversity and evolution of the Candidate Phyla Radiation (CPR) bacteria

Jillian Banfield
Simonetta Gribaldo

The availability of genomic data from uncultured microbial lineages from a wide variety of environments is dramatically changing our view of microbial diversity. Recently, these techniques have brought to light a huge number of bacterial groups that, together with previously reported sequences, were used to define the Candidate Phyla Radiation (CPR).The CPR may constitute up to 50% of all bacterial diversity on Earth, yet it remains largely uncharacterized. This project will unite the complementary expertise of the Gribaldo (phylogenomics, evolutionary microbiology, Institut Pasteur) and...

Attosecond dynamics in topological insulators

Stephen Leone
Marino Marsi

Topological insulators (TI’s) are a new class of quantum materials characterized by conduction at the surface, while the bulk is insulating. The goal of this project is to investigate very short time dynamics in these topological insulator materials, at the limits of the shortest possible time resolution achievable today. It brings together the groups of S. Leone in Berkeley and M. Marsi, creating a uniquely advantageous combination with the ambition of pushing forward the frontiers of this research domain. The group of the French partner at LPS Orsay has been among the pioneers of this...

Advanced Potential Energy Surfaces for Condensed Phase Simulations: Theory and Applications

Teresa Head-Gordon
Jean-Philip Piquemal

The failures of pairwise additive force fields are accumulating and unambiguous for molecular simulation of physical systems, and higher accuracy force fields that introduce new terms that describe many-body polarization and non-classical effects such as charge transfer and penetration are needed. The vastly greater complexity of this additional physics poses great challenges for rational force field design as well algorithmic and software challenges that inhibit their application to grand challenge chemistry applications. The joint project between Prof. Jean-Philip Piquemal (Sorbonne...