Transportation insecurity in Detroit and beyond

Alexandra Murphy discusses why 36% of Detroiters have trouble getting where they need to go and how a new tool could guide better transportation solutions

 News Release 23-Jan-2025

University of Michigan

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More than a third of Detroit residents (36%) can't get from place to place in a safe or timely manner. 

This is the main finding of a new study led by Alexandra Murphy, associate director of social science research at Mcity and assistant research scientist at U-M's Poverty Solutions, and first author Lydia Wileden, a U-M alum and assistant research professor at the University of Connecticut. 

 

They measured this with a tool created by Murphy and her team called the Transportation Security Index. One aim of the TSI is to help local governments plan transportation investments, similar to the way food security indices clarify what kinds of food resources are needed and where. 

 

A report issued earlier this month by the National Academies of Science, Engineering and Medicine recommended the use of transportation security indices to guide local investments in transportation resources, naming the U-M index as a good example. Detroit's transportation insecurity is more than twice the national average of 17% (established in 2022). 

 

Murphy discusses what the TSI can reveal about issues facing Detroit and other U.S. cities.

 

Why focus on transportation insecurity?

 

The ability to get to the places we need and want to go has a huge impact on an individual's quality of life: It allows us to get to work, visit the doctor, attend parent-teacher conferences, search for housing, take care of our aging parents, visit friends, vote, and so on. Being able to do all of these things likely has implications for everything from our physical and mental health to our financial security and the flourishing of our children. Even if we're not personally transportation insecure, the security of others can affect us: for instance, employers have a vested interest in their employees arriving to work on time.

 

The TSI allows us to identify who is (and is not) regularly able to get from place to place in a safe or timely manner, quantify how big of a problem transportation insecurity is, and assess—through measurement and additional data collection—how this impacts outcomes relevant to individual and community well-being. 

 

Our results show that those demographic groups most vulnerable to experiencing transportation insecurity are groups that have the least access to opportunity, including people living below the poverty line and those with disabilities. The TSI allows researchers to investigate how inequality both drives people's experience with transportation insecurity and is a result of it. 

 

Why a transportation security index? How would it change the way transportation investments are made?

 

The TSI allows us to consider transportation at the individual level. For a long time, when we talked about making investments in transportation, we focused on two things: infrastructure and communities. We've long thought about improving people's ability to get around by investing in roads, bridges, sidewalks, public transportation, and so on. And when we make those investments, we think about doing them at the neighborhood or community level.

 

Looking at transportation insecurity at the individual level allows us to see that investments in communities don't always reach individuals within those communities. With the TSI, we can then begin to answer questions like: What  shapes people's transportation insecurity? Are they unable to pay for their car to be repaired? Is public transit too far away to access? The different challenges that people experiencing transportation insecurity face may require different policy responses.

 

Detroit represents the first time you've applied the TSI to a specific city. What stood out to you about the results that came back from the survey?

 

Many of the 1 in 3 Detroiters who experience transportation insecurity have had to reschedule appointments or skip trips altogether. Our data also reveal the more relational and emotional dimensions of transportation insecurity. Of Detroiters reporting any level of transportation insecurity, 84% reported feeling bad about their situation and 56% reported that their transportation issues impacted their relationships in the previous 30 days. 

 

What do your findings tell us about the relationship between modes of transportation and transportation insecurity in Detroit? 

 

Given Detroit's sprawling, low-density built environment, it's not surprising that Detroiters without cars are nearly three times as likely to experience transportation insecurity compared to car owners. We also see that owning a car in the motor city doesn't fully solve insecurity. Many Detroiters have unreliable vehicles, share cars with other household members, or lack car insurance, which is very expensive in Michigan. All of this increases the likelihood of experiencing insecurity.

 

Regarding public transit, the vast majority of Detroiters, 82%, reported they had not used it in the past 30 days, and our results suggest the cost of transit cannot fully explain this low usage. There is research suggesting the closer one lives to transit, the more likely one will use it, but we're not seeing that in Detroit. The average transportation-insecure Detroiter lives within a three minute walk to at least one bus stop. Moreover, we find that as one's distance from a transit stop increases, the likelihood of experiencing transportation insecurity goes down. 

 

Perhaps it is because the routes people live close to don't take them where they want or need to go. Perhaps it is because the routes available involve commutes that are too long. But having identified this relationship suggests we need more research to understand what it will take to make our transit systems better serve those who are transportation insecure.

 

How is the TSI being used beyond Detroit?

 

One example is the Mobility, Access and Transportation Insecurity demonstration program at the University of Minnesota, funded by the Federal Transit Administration. It is using the TSI to evaluate whether different kinds of investments in transportation are moving people from "transportation insecurity" to "transportation security." 

 

The state of Minnesota and some counties are including the TSI on surveys, documenting the prevalence of transportation insecurity. By including it in future surveys, these governments will be able to see if transportation insecurity is going up or down, which will help them understand whether their investments are moving the needle.

 

Academic institutions have also been partnering with local communities to understand what transportation insecurity looks like in their own backyards. For instance, in addition to Detroit, the Detroit Metro Area Communities Study has also fielded surveys that include the TSI in Grand Rapids, Flint and Ypsilanti. Johns Hopkins researchers running the Baltimore Area Survey have done the same. 

 

It is our hope that the TSI gets incorporated into more recurring, national surveys. Not only would this allow us to to track the ebb and flow of these issues at the national, state and local level, but it would also help us identify geographic hot spots where transportation insecurity is clustering in ways we may not be seeing with other measurement tools. 

 

Murphy is also a faculty associate at U-M's Population Studies Center.

COWABUNGA, WAVE OUT THERE

HKUST researcher unveiling the uncharted reaction pathways of carbon dioxide in supercritical water

Hong Kong University of Science and Technology

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Authors of the paper (from left to right): Prof. Yuan Yao, Professor from the Department of Mathematics, Prof. Chu Li, Research Assistant Professor from the Department of Physics, and Prof. Ding Pan, Associate Professor from the Department of Physics.  

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Credit: HKUST

A research team led by Associate Professor Ding PAN from the Department of Physics and the Department of Chemistry at the Hong Kong University of Science and Technology (HKUST), in collaboration with Prof. Yuan Yao from the Department of Mathematics, has made significant discoveries regarding the complex reaction mechanisms of carbon dioxide (CO₂) in supercritical water. These findings are crucial for understanding the molecular mechanisms of CO₂ mineralization and sequestration in nature and engineering, as well as the deep carbon cycle within the Earth's interior. This understanding will help pave the way for new directions in future carbon sequestration technologies. The study was published in the Proceedings of the National Academy of Sciences (PNAS)*.

The dissolution of CO₂ in water and its subsequent hydrolysis reactions are key processes for effective carbon capture and mineralization storage, playing a significant role in carbon sequestration to mitigate global warming. Prof. Pan's team developed and applied first-principles Markov models to reveal the reaction mechanisms of CO₂ with supercritical water in both bulk and nanoconfined environments. They discovered that pyrocarbonate (C₂O₅²⁻) is a stable and important reaction intermediate in nanoconfined environments, which had been previously overlooked because pyrocarbonate is highly unstable and decomposes rapidly in aqueous solutions. The unexpected appearance of pyrocarbonate is related to the superionic behavior of the confined solutions. Additionally, they found that carbonation reactions involve collective proton transfer along transient water chains, which exhibits concerted behavior in bulk solutions but proceeds stepwise under nanoconfinement. This study demonstrates the great potential of first-principles Markov models in elucidating complex reaction kinetics in aqueous solutions.

"Our innovative approach has enabled us to discover a new pathway for CO₂ dissolution involving pyrocarbonate ions," said Prof. Chu LI, Research Assistant Professor from the Department of Physics. "Our efficient computational method does not rely on prior knowledge and can automatically identify reaction pathways without human bias, revealing unknown reaction mechanisms based on the first principles of physics."

Prof. Ding Pan added, "Our method employs unsupervised learning techniques to reveal the importance of large oxocarbons in aqueous reactions under extreme conditions, while also demonstrating that nanoconfinement can be an effective strategy for regulating chemical processes. These findings are expected to provide new directions for future carbon sequestration technologies."

The research was supported by the Hong Kong Research Grants Council, the Croucher Foundation, and the Excellent Young Scientists Fund of the National Natural Science Foundation of China. Part of the computational work was carried out on the Tianhe-2 supercomputer at the National Supercomputer Center in Guangzhou.

*Note: Prof. Chu Li, Research Assistant Professor, is the first author of the paper and, along with Prof. Ding Pan, serves as the corresponding author.

The first-principles Markov state models elucidate the complex reaction kinetics of CO2 in supercritical water. (Image courtesy of Prof. Chu Li, Jie Shu, Prof. Ding Pan)

Credit

Prof. Chu Li, Jie Shu, Prof. Ding Pan

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2406356121 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Unveiling hidden reaction kinetics of carbon dioxide in supercritical aqueous solutions

 

A groundbreaking approach: Researchers at The University of Texas at San Antonio chart the future of neuromorphic computing

The review article published in Nature, titled “Neuromorphic Computing at Scale,” examines the state of neuromorphic technology and presents a strategy for building large-scale neuromorphic systems.

University of Texas at San Antonio

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Dhireesha Kudithipudi (second from right), founding director of MATRIX at UTSA, chats with students during the NSF AI Spring School at UTSA's San Pedro I building.

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Credit: The University of Texas at San Antonio

A review article about the future of neuromorphic computing by a team of 23 researchers, including two authors from UTSA, was published today in Nature. Dhireesha Kudithipudi, the Robert F. McDermott Endowed Chair in Engineering and founding director of MATRIX: The UTSA AI Consortium for Human Well-Being, served as the lead author, while Tej Pandit, a UTSA doctoral candidate in computer engineering, is one of the co-authors. The review article, titled “Neuromorphic Computing at Scale,” examines the state of neuromorphic technology and presents a strategy for building large-scale neuromorphic systems.

The research is part of a broader effort to advance neuromorphic computing, a field that applies principles of neuroscience to computing systems to mimic the brain’s function and structure. Neuromorphic chips have the potential to outpace traditional computers in energy and space efficiency as well as performance, presenting substantial advantages across various domains, including artificial intelligence, health care and robotics. As the electricity consumption of AI is projected to double by 2026, neuromorphic computing emerges as a promising solution.

The authors say that neuromorphic systems are reaching a “critical juncture,” with scale being a key metric to track the progress of the field. Neuromorphic systems are rapidly growing, with Intel’s Hala Point already containing 1.15 billion neurons. The authors argue that these systems will still need to grow considerably larger to tackle highly complex, real-world challenges.

“Neuromorphic computing is at a pivotal moment, reminiscent of the AlexNet-like moment for deep learning,” said Kudithipudi. “We are now at a point where there is a tremendous opportunity to build new architectures and open frameworks that can be deployed in commercial applications. I strongly believe that fostering tight collaboration between industry and academia is the key to shaping the future of this field. This collaboration is reflected in our team of co-authors.”

Kudithipudi has done extensive work in the field of neuromorphic computing. Last year, she secured a $4 million grant from the National Science Foundation to launch THOR: The Neuromorphic Commons, a first-of-its-kind research network providing access to open neuromorphic computing hardware and tools in support of interdisciplinary and collaborative research. Catherine Schuman (University of Tennessee, Knoxville) and Gert Cauwenberghs (University of California, San Diego), co-authors on the article, are also co-investigators on THOR.

In addition to expanded access, the team also calls for the development of a wider array of user-friendly programming languages to lower the barrier of entry into the field. They believe this would foster increased collaboration, particularly across disciplines and industries.

Steve Furber, emeritus professor of computer engineering at the University of Manchester, is among the authors on the project. Furber specializes in neural systems engineering and asynchronous systems. He led the development of the million-core SpiNNaker1 neuromorphic computing platform at Manchester and co-developed SpiNNaker2 with TU Dresden.

“Twenty years after the launch of the SpiNNaker project, it seems that the time for neuromorphic technology has finally come, and not just for brain modeling, but also for wider AI applications, notably to address the unsustainable energy demands of large, dense AI models,” said Furber. “This paper captures the state of neuromorphic technology at this key point in its development, as it is poised to emerge into full-scale commercial use.”

To achieve scale in neuromorphic computing, the team proposes several key features that must be optimized, including sparsity, a feature observed in the biological brains. The brain develops by forming numerous neural connections (densification) before selectively pruning most of them. This strategy optimizes spatial efficiency while retaining information at high fidelity. If successfully emulated, this feature could enable neuromorphic systems that are significantly more energy-efficient and compact.

“This paper is one of the most collaborative efforts to date toward outlining the field of neuromorphic computing with emphasis on scale, ecosystem and outreach between researchers, students, consumers and industry,” said Pandit. “Representatives of many key research groups came together to share crucial information about the current state and future of the field with the goal of making large-scale neuromorphic systems more mainstream.”

Pandit is pursuing his doctoral degree at UTSA under Kudithipudi. His focus is on training AI systems to learn continually without overwriting existing information. He recently published about the topic.

“UTSA is deeply invested in developing knowledge in this field, which has the potential to catalyze a number of technologies and address grand challenges in the world today such as energy waste and trustworthy AI,” said JoAnn Browning, UTSA interim vice president for research. “I am extremely proud to see Dr. Kudithipudi and Tej Pandit making such significant contributions to harness the power of this promising technology, particularly on the heels of the launch of UTSA's new neuromorphic commons, THOR.”

The UTSA researchers worked with esteemed authors from various institutions, national laboratories and industry partners. These include the University of Tennessee, Knoxville, Sandia National Laboratories, Rochester Institute of Technology, the University of Pittsburgh, Intel Labs, Technische Universität Dresden, the U.S. Naval Research Laboratory, Google DeepMind, the Italian Institute of Technology, UC San Diego, the Institute of Neuroinformatics at the University of Zürich and ETH Zürich, the National Institute of Standards and Technology, Oak Ridge National Laboratory, SpiNNcloud Systems GmbH, the Indian Institute of Science, Royal Holloway, University of London, and The University of Manchester. This collaboration underscores the extensive network and interdisciplinary approach taken by UTSA researchers to advance their groundbreaking work.

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Journal

Nature

DOI

10.1038/s41586-024-08253-8 

Article Title

Neuromorphic Computing at Scale

Article Publication Date

22-Jan-2025

Research team led by OHIO’s Sabrina Curran finds new evidence that pushes back the arrival of early hominins in Europe; discovery published in Nature Communications

Ohio University

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Cut marks found on bones that appear to have been made by early hominins using stone tools at the site of Grăunceanu, Romania, dating to approximately 1.95 million years ago.

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Credit: Dr. Sabrina Curran

Research led by Ohio University Associate Professor of Anthropology Dr. Sabrina Curran reveals new evidence of early hominin activity in Europe, suggesting that hominins were present on the continent far earlier than previously thought.

The team of researchers, also led by co-principal investigators Dr. Alexandru Petculescu, of the “Emil Racoviţă” Institute of Speleology, Romanian Academy in Bucharest, Romania and Dr. Claire E. Terhune, an associate professor in the Department of Anthropology at the University of Arkansas, have uncovered multiple cut marked bones that appear to have been made by early hominins using stone tools at the site of Grăunceanu, Romania. These cut marks, dating to approximately 1.95 million years ago, represent some of the earliest evidence of tool use and meat processing in Eurasia.

The discovery, published in Nature Communications, sheds new light on the timing and extent of hominin dispersal across Eurasia. While previous evidence indicated hominin presence in Dmanisi, Georgia, around 1.8 million years ago, the discovery at Grăunceanu pushes this timeline even further back, suggesting that hominins may have been present in Eurasia by at least 2 million years ago.

“The discovery of these cut marks is significant because it pushes back the timeline of hominin activity in Eurasia,” Curran said. “While evidence of stone tools has been found in other parts of the world, the presence of these marks on bones offers a rare and valuable glimpse into the behavior of early human ancestors.”

Curran and team’s research builds on decades of previous excavations in Romania, where major fossil discoveries were made in the 1960s and 1980s. The bones, which had been curated in the “Emil Racoviţă” Institute of Speleology and the Museum of Oltenia, were largely overlooked until recent re-examinations by Curran and her international team.

“We didn’t initially expect to find much,” Curran explained. “But during a routine check of the collections we found several cut marked bones. This led to further investigation in collaboration with Dr. Briana Pobiner of the Smithsonian Institution and Dr. Michael Pante, of Colorado State University, and the discovery of other distinct marks across different bones, suggesting deliberate butchering activities.”

The discovery is especially notable because it predates the well-known Dmanisi site in Georgia—previously considered the earliest evidence of hominin activity outside of Africa—by roughly 200,000 years. This new finding places Romania as a crucial location for understanding the spread and behaviors of early human ancestors.

The findings are supported by biostratigraphic data and high-resolution U-Pb dating techniques, which have established the site's age with remarkable precision. In addition, Dr. Virgil Drăguşin and the team used isotope analysis to reconstruct the environments that these hominins would have experienced in this area at the time. Those results indicate that the region would have experienced seasonal fluctuations in temperature, much like today, but perhaps with increased levels of rainfall.

According to Curran, this discovery has significant implications for our understanding of human evolution, suggesting that early hominins may have had a widespread presence across Eurasia long before the more established hominin sites in Europe.

"The Grăunceanu site represents a pivotal moment in our understanding of human prehistory, Curran said. “It demonstrates that early hominins had already begun to explore and inhabit diverse environments across Eurasia, showing an adaptability that would later play a crucial role in their survival and spread."

In addition to the cut-marked bones, Curran’s team has also uncovered fossils of a wide range of species that lived in Romania at the time, shedding light on the environment in which these early humans lived. The site, which once hosted a diverse range of species, has yielded fossils of saber-toothed cats, giraffes, and even an extinct species of pangolin. This finding highlights the extraordinary biodiversity of the region during the early Pleistocene.

“The evidence coming out of Romania suggests that early hominins were much more adaptable than we previously thought,” Curran added. “These early humans were capable of surviving and thriving in a variety of environments.”

In addition to being published in Nature Communications, Curran and her team will present their findings at the American Association of Biological Anthropologists (AABA) conference in March 2025.

“The history of human evolution is far more complex and intricate than we could have imagined, and we are just beginning to uncover the many chapters of that story.”

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Journal

Nature Communications

Method of Research

Observational study

Subject of Research

People

Article Title

Hominin presence in Eurasia by at least 1.95 million years ago

Article Publication Date

24-Jan-2025

The secret ‘sex lives’ of bacteria: Study challenges old ideas about how species form

 Release 23-Jan-2025
Georgia Institute of Technology

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Salinibacter ruber cells (green) under the microscope. Other colors represent different organisms in the saltern. (Credit: Tomeu Viver)

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Credit: Tomeu Viver

When Kostas Konstantinidis proved that many microbes — like plants and animals — are organized into species, he upended a long-held scientific belief. Scientists widely believed that bacteria, due to their unique genetic exchange mechanisms and the vast size of their global populations, did not — and could not — form distinct species.

New research from Konstantinidis and collaborators further challenges this notion, suggesting that not only do bacteria form species, but they also maintain cohesive species through a process that is somewhat “sexual." 

“The next question for us was how individual microbes in the same species maintain their cohesiveness. In other words, how do bacteria stay similar?” said Konstantinidis, the Richard C. Tucker Professor in Georgia Tech’s School of Civil and Environmental Engineering. 

Bacterial and other microbes are thought to evolve primarily through binary fission, meaning asexual reproduction, while also engaging in infrequent genetic exchange. Using a novel bioinformatic method for detecting gene transfer, along with a new trove of whole genome data, Konstantinidis and an international team of researchers tested their hypothesis for how species emerge and are maintained. They found that bacteria evolve and form species more “sexually” than previously thought. 

Their research was published in the journal Nature Communications.

To investigate how microbial species maintain their distinct identities, the team analyzed the complete genomes of microbes from two natural populations. They collected and sequenced over 100 strains of Salinibacter ruber (a salt-loving microbe) from solar salterns in Spain. Then they analyzed a set of previously published Escherichia coli genomes isolated from livestock farms in the U.K. They compared the genomes of closely related microbes to see how genes were being exchanged.

They found that a process called “homologous recombination” plays a major role in keeping microbial species together. Homologous recombination occurs when microbes exchange DNA with each other and integrate the new DNA into their genome by replacing their own similar DNA. They observed that recombination occurs frequently and randomly across the entire genome of microbes, and not just in a few specific regions. 

“This may be fundamentally different from sexual reproduction in animals, plants, fungi, and non-bacterial organisms, where DNA is exchanged during meiosis, but the outcome in terms of species cohesion may be similar,” Konstantinidis said. “This constant exchange of genetic material acts as a cohesive force, keeping members of the same species similar.” 

The researchers also observed that members of the same species are more likely to exchange DNA with one another than with members of different species, further contributing to distinct species boundaries.

“This work addresses a major, long-lasting problem for microbiology that is relevant for many research areas,” Konstantinidis said. “That is, how to define species and the underlying mechanisms for species cohesion.”

This research has implications for several fields, from environmental science and evolution to medicine and public health, and offers valuable insights for identifying, modeling, and regulating clinically or environmentally important organisms. The methodology developed during the research also provides a molecular toolkit for future epidemiological and micro-diversity studies.

 

Note: The research was made possible by contributions from the groups of Ramon Rossello-Mora at IMEDEA in Majorca, Spain, and Rudolf Amann at the Max Planck Institute for Marine Microbiology in Bremen, Germany, who obtained data from the natural microbial populations and equally contributed to the data analysis and interpretations. 

Citation: Conrad, R.E., Brink, C.E., Viver, T. et al. Microbial species and intraspecies units exist and are maintained by ecological cohesiveness coupled to high homologous recombination. Nat Commun 15, 9906 (2024). 

DOI: https://doi.org/10.1038/s41467-024-53787-0

Funding: U.S. Department of Energy, U.S. National Science Foundation, European Regional Development Fund

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Journal

Nature Communications

DOI

10.1038/s41467-024-53787-0 

Article Title

Microbial species and intraspecies units exist and are maintained by ecological cohesiveness coupled to high homologous recombination