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Two professors from the College of Arts and Sciences—Rebecca Safran and Tin Tin Su—and two professors from the College of Engineering and Applied Science—Aaron Clauset and R. Steven Nerem—have been elected (��������).��

They are among nearly 500 scientists, engineers and innovators who have been recognized this year for their scientifically and socially distinguished achievements by one of the world’s largest general scientific societies and publisher of the��Science��family of journals. They also join a cohort of more than 80 CU Boulder faculty members who previously received the honor.

Safran is a professor of ecology and evolutionary biology who has led groundbreaking research on the evolution of new species; Su is a professor and the chair of molecular, cellular and developmental biology, whose research is leading to novel cancer therapies. Clauset is a professor of computer science and an internationally recognized expert on network science, data science and complex systems; Nerem is a professor of aerospace engineering and an expert in satellite remote sensing and geodesy.

A tradition dating back to 1874, election as an AAAS fellow is a lifetime honor, and all fellows are expected to meet the commonly held standards of professional ethics and scientific integrity. Distinguished past honorees include Alan Alda, Steven Chu, W.E.B DuBois, Thomas Edison, Grace Hopper, Ayanna Howard, Irwin Jacobs, Mae Jemison, Maria Mitchell and Ellen Ochoa.��

“This year’s AAAS fellows have demonstrated research excellence, made notable contributions to advance science, and delivered important services to their communities,” said Sudip Parikh, AAAS chief executive officer and executive publisher of the��Science journals. “These fellows and their accomplishments validate the importance of investing in science and technology for the benefit of all.”

Read more about CU Boulder's latest AAAS lifetime fellows.

Aaron Clauset

Clauset has been a faculty member in the Department of Computer Science and the��BioFrontiers Institute since 2010. Clauset’s research interests are broad, from��, to��shining light on potential biases in journal paper acceptance.��

In 2025, he made Clarivate’s�� list for demonstrating “broad and significant influence” in his field. He is the recipient of a National Science Foundation CAREER Award and the Erdos-Renyi Prize in Network Science. Clauset also serves as an external faculty member of the Santa Fe Institute.��

Clauset said he is honored to be elected as a fellow of AAAS, a group that has long championed the role of science in society.

“Science offers the best way to find order and meaning in the complex and often chaotic world we live in. My research shows how powerful computational tools can reveal the hidden structures of complex systems, and helps us use that understanding for the public good,” he said.��

“I am grateful to my students and colleagues at CU Boulder. This honor reflects our shared commitment to using data-driven science to understand and, ultimately, improve the complex social structures we all inhabit.”

R. Steven Nerem

Nerem is an aerospace engineering expert with over 30 years of experience. He was recruited to CU Boulder in 2000 as a full professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences and currently serves as director of the��Colorado Center for Astrodynamics Research.

Nerem uses satellite-based techniques to monitor changes in Earth’s shape and gravity field due to shifts in sea level, distribution of water and ice planetwide, and vertical crustal motion. The AAAS election makes Nerem the second member of his family to be part of the prestigious body.��

“This is a great honor. I really enjoy doing research—it’s like a hobby,” Nerem said.��“The most important thing to me about my selection is that my father, who passed away in 2020, was also an AAAS fellow, so it’s nice to follow in his footsteps.”

Nerem has been part of multiple NASA missions, including the ongoing GRACE-FO and Sentinel 6B satellites. He leads an active research group, with more than 480 publications, including 12 in 2025 alone. He is a fellow of the American Geophysical Union and was the inaugural recipient of the Earth Science and Applications Award from the American Astronautical Society.

Rebecca Safran

Safran, whose passion for biology took root in a plant taxonomy class during her undergraduate studies at the University of Michigan, is a professor in the department of Ecology and Evolutionary Biology. She and her research team study , focusing on the causes and consequences of individual variation across different scales of time and space.��

Because studying the formation of new species can be difficult—since most species are millions of years old and what caused them to diverge from their ancestors often can’t be determined—Safran and her team study barn swallows, a very closely related group of populations of migratory birds that are currently diverging. This allows Safran and her team to study the process of speciation in real time.

Safran won a National Science Foundation Early Career Development award to study speciation in barn swallows across their entire, expansive breeding range throughout the Northern Hemisphere and Middle East. During the COVID-19 pandemic, when it wasn’t possible to conduct research in other countries, Safran and her team began focusing on the rapid decline in the population of barn swallows and its implications—using a highly integrative approach including behavioral, physiological and genetic perspectives.

Her team’s research has been published in more than 120 peer-reviewed journals, including��Science, Nature��and��Current Biology. Safran also co-edited a recent book on speciation.

“None of this work is possible without the incredible collaboration with students, colleagues at CU and around the world, private landowners who allow us to study populations of barn swallows on their properties and continuous funding support by the National Science Foundation and other agencies,” Safran says.��

“I am especially honored to have worked with so many talented undergraduate, graduate and postdoctoral students.”

Tin Tin Su

Su is a professor in the department of Molecular, Cellular & Developmental Biology. Su, who attended Woodstock School in Mussoorie, Uttarakhand, India, credits her experiences there, in part, with that her ideal environment is one in which “you do respect the elders or people who have had more experience or authority. But at the same time, if it doesn't seem right, you question it.”

Throughout her career, Su and her research colleagues have sought to develop new ways of attacking cancer. Through research on how tissues and organs regenerate after being damaged by X-rays in fruit flies, they synthesized the chemical SVC112, which helps prevent cancer cells from regrowing following radiation exposure. Su and her colleagues focused on the fruit fly because this insect shares more than 70% of disease-relevant genes with humans.

SVC112 is based on the chemical bouvardin found in the firecracker bush (Bouvardia ternifolia) that grows in the Southwest U.S. and Mexico. Su and her colleagues discovered that bouvardin can prevent regeneration of tissues in fruit flies.

More recently, Su, who also is a member of the CU Cancer Center, and her colleague Antonio Jimeno, used SVC112 to target cancer stem cells in head and neck cancers. They are in the process of applying to the FDA to test SVC112 in human trials.

Su also has participated in the CU Boulder Community Perspectives Program, conducting outreach in several rural Colorado communities that led to a research collaboration with Colorado State University Pueblo to assess the effect of heavy metals on the genome in��fruit fly��and human cells.

“I do what I do because I love science,” Su says. “The potential to help cancer patients in Colorado and beyond makes it even better. So, to be named an AAAS fellow is really the cherry on top!”