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Ronald A. Rohrer, Cecil & Ida Green Chair and professor of engineering at SMU Lyle, honored with TAMEST membership

“I’ve stayed close to industry to be a practicing engineer and close to academia to conduct deeper research on hard problems.” — Ronald A. Rohrer.

Legendary inventor and scholar Ronald A. Rohrer, Cecil & Ida Green Chair and Professor of Engineering in SMU’s Lyle School of Engineering, has been named to The Academy of Medicine, Engineering, and Science of Texas (TAMEST).

The nonprofit organization, founded in 2004, brings together the state’s top scientific, academic and corporate minds to support research in Texas.

The organization builds a stronger identity for Texas as an important destination and hub of achievement in these fields. Members of The National Academies of Sciences, Engineering and Medicine and the state’s nine Nobel Laureates comprise the 270 members of TAMEST. The group has 18 member institutions, including SMU, across Texas.

Rohrer joins three other distinguished SMU faculty members in TAMEST — Fred Chang, executive director of the Lyle School’s Darwin Deason Institute for Cyber Security; Delores Etter, founding director of the Lyle School’s Caruth Institute for Engineering Education and electrical engineering professor emeritus; and David Meltzer, Henderson-Morrison Chair and professor of prehistory in anthropology in Dedman College.

Considered one of the preeminent researchers in electronic design automation, Rohrer’s contributions to improving integrated circuit (IC) production have spanned over 50 years. Rohrer realized early on that circuit simulation was crucial to IC design for progress in size reduction and complexity. Among his achievements was introducing a sequence of circuit simulation courses at the University of California, Berkeley, that evolved into the SPICE (Simulation Program with Integrated Circuit Emphasis) tool, now considered the industry standard for IC design simulation. At Carnegie Mellon University, Rohrer introduced the Asymptotic Waveform Evaluation (AWE) algorithm, which enabled highly efficient timing simulations of ICs containing large numbers of parasitic elements.

“The appointment of Ron Rohrer into TAMEST will increase the visibility of Lyle’s outstanding faculty members,” said Marc P. Christensen, dean of the Lyle School of Engineering.

“Through TAMEST, Rohrer will share his vast knowledge and inspire additional collaborative research relationships with other outstanding Texas professors and universities. This will elevate SMU and the state as a leading center of scholarship and innovation,” Christensen said.

Once an SMU electrical engineering professor back in the late 70’s, Rohrer rejoined the Lyle School as a faculty member in 2017. He is professor emeritus of electrical and computer engineering at Carnegie Mellon and Rohrer’s career has included roles in academia, industrial management, venture capital, and start-up companies.

“I’ve stayed close to industry to be a practicing engineer and close to academia to conduct deeper research on hard problems,” said Rohrer.

According to Rohrer, one pressing problem is analog integrated circuit design automation, also the name of the project-based research course he’s currently teaching.

“In the analog domain, it’s hard to design a 20-transistor circuit. My goal is to make analog integrated circuit design more accessible to students and industry, especially for our local corporate partners,” he said. “I want to get the ball rolling so younger engineers can keep it moving toward a complete solution.”

Along with his membership in TAMEST and the National Academy of Engineering, Rohrer is an IEEE Life Fellow. His professional service includes several other prominent positions with IEEE, AIEE and U.S. government committees. He is the author and co-author of five textbooks and more than 100 technical papers as well as the holder of six patents. Rohrer has received 11 major awards, including the IEEE Education Medal and the NEC C&C Prize.

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Prehistoric humans formed complex mating networks to avoid inbreeding

A new study has sequenced the genomes of individuals from an ancient burial site in Russia and discovered that they were, at most, first cousins, indicating that they had developed sexual partnerships beyond their immediate social and family group.

A new study has identified when humans transitioned from simple systems designed to minimize inbreeding to more complex ones suitable for hunter-gatherer societies.

The study findings are reported in the journal Science and demonstrate that, by at least 34,000 years ago, human hunter-gatherer groups had developed sophisticated social and mating networks that minimized inbreeding.

The study examined genetic information from the remains of modern humans who lived during the early part of the Upper Palaeolithic, a period when modern humans from Africa first colonized western Eurasia, eventually displacing the Neanderthals who lived there before.

The results suggest that people deliberately sought partners beyond their immediate family, and that they were probably connected to a wider network of groups from within which mates were chosen, thus avoiding inbreeding.

The research was carried out by an international team of academics, led by the University of Cambridge, U.K., and the University of Copenhagen, Denmark. The team included SMU archaeologist David J. Meltzer, whose expertise includes the First People in the Americas.

The researchers sequenced the genomes of four individuals from Sunghir, a famous Upper Palaeolithic site in Russia, which was inhabited about 34,000 years ago.

The article, “Ancient genomes show social and reproductive behavior of early Upper Paleolithic foragers,” is published in the Oct. 5, 2017 issue of Science.

Complex mating systems may partly explain modern human survival
Among recent hunter-gatherers, the exchange of mates between groups is embedded into a cultural system of rules, ceremonies and rituals. The symbolism, complexity and time invested in the extraordinarily rich objects and jewellery found in the Sunghir burials, as well as the burials themselves, suggest that these early human societies symbolically marked major events in the life of individuals and their community in ways that foreshadow modern rituals and ceremonies — birth, marriage, death, shared ancestry, shared cultures.

The study’s authors also hint that the early development of more complex mating systems may at least partly explain why modern humans proved successful while other, rival species, such as Neanderthals, did not. More ancient genomic information from both early humans and Neanderthals is needed to test this idea.

The human fossils buried at Sunghir are a unique source of information about early modern human societies of western Eurasia. Sunghir preserves two contemporaneous burials – that of an adult man, and that of two children buried together and which includes the symbolically modified remains of another adult.

To the researchers’ surprise, however, these individuals were not closely related in genetic terms; at the very most, they were second cousins. This is true even for the two children who were buried head-to-head in the same grave.

“What this means is that people in the Upper Palaeolithic, who were living in tiny groups, understood the importance of avoiding inbreeding,” said Eske Willerslev, a professor at St John’s College and the University of Copenhagen, who was senior author on the study. “The data that we have suggest that it was being purposely avoided. This means that they must have developed a system for this purpose. If the small hunter and gathering bands were mixing at random, we would see much greater evidence of inbreeding than we have here.”

Early human societies changed ancestral mating system
The small family bands were likely interconnected within larger networks, facilitating the exchange of peoples between bands in order to maintain diversity, said Martin Sikora, a professor at the Centre for GeoGenetics at the University of Copenhagen.

Most non-human primate societies are organized around single-sex kin (matrilines or patrilines), where one of the sexes remains resident and the other migrates to another group, thus minimizing inbreeding. At some point, early human societies changed the ancestral mating system into one in which a large number of the individuals that form small resident/foraging units are non-kin, where the relations among units that exchange mating partners are formalized through complex cultural systems.

In at least one Neanderthal case, an individual from the Altai Mountains who died about 50,000 years ago, inbreeding was not avoided, suggesting that the modern human cultural systems that allows to decouple the size of the resident community from the danger of inbreeding was not in place. This leads the researchers to speculate that an early, systematic approach to preventing inbreeding may have helped modern humans to thrive in relation to with other hominins.

This should be treated with caution, however.

“We don’t know why the Altai Neanderthal groups were inbred,” Sikora said. “Maybe they were isolated and that was the only option; or maybe they really did fail to develop a network of connections. We will need more genomic data of diverse Neanderthal populations to be sure.”

Upper Palaeolithic human groups sustained very small group sizes
The researchers were able to sequence the complete genomes of all four individuals found within the two graves at Sunghir. These data were compared with information on both modern and ancient human genomes from across the world.

They found that the four individuals studied were genetically no closer than second cousins, while the adult femur filled with red ochre found in the youngsters’ grave would have belonged to an individual no closer than great-great grandfather of the boys. “This goes against what many would have predicted,” Willerslev said. “I think many researchers had assumed that the people of Sunghir were very closely related, especially the two youngsters from the same grave.”

The people at Sunghir may have been part of a network similar to that of modern day hunter-gatherers, such as Aboriginal Australians and some historical Native American societies. Like their Upper Palaeolithic ancestors, these societies lived in fairly small groups of some 25 people, but they were also connected to a larger community of perhaps 200 people, within which there were rules governing with whom individuals can form partnerships.

“The results from Sunghir show that Upper Palaeolithic human groups could sustain very small group sizes by embedding them in a wide social network of other groups maintained by sophisticated cultural systems,” said Marta Mirazón Lahr, a professor at the University of Cambridge.

Willerslev also highlights a possible link with the unusual sophistication of the ornaments and cultural objects found at Sunghir. Such band-specific cultural expressions may have been used to signal who are “we” versus who are “they,” and thus a means of reinforcing a shared identity built on marriage exchange across foraging units. The number and sophistication of personal ornaments and artefacts found at Sunghir are exceptional even among other modern human burials, and not found among Neanderthals and other hominins.

“The ornamentation is incredible and there is no evidence of anything like that with other hominins,” Willerslev added. “When you put the evidence together, it seems to be telling us about the really big questions: what made these people who they were as a species, and who we are as a result.”

Ancient genomics throw light on aspects of social life
These results show the power of ancient genomics to throw light on aspects of social life among early humans, and pave the way for further studies to explore variation in social and demographic strategies in prehistoric socieities.

“Much of human evolution is about changes in our social and cultural behavior, and the impact this has had on our success as a species. This study takes us a step further toward pinpointing when and why the things that make humans unique evolved,” said Robert Foley, a professor at the University of Cambridge.

Meltzer is Henderson-Morrison Professor of Prehistory in the SMU Department of Anthropology in Dedman College. As a scientist who studies how people first came to inhabit North America, Meltzer in 2009 was elected a member of the National Academy of Sciences in recognition for his achievements in original scientific research. In 2013 he was elected to the American Academy of Arts and Sciences. — University of Cambridge, SMU

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A composite window into human history

Better integration of ancient DNA studies with archaeology promises deeper insights.

DNA testing alone of ancient human remains can’t resolve questions about past societies.

It’s time for geneticists and archaeologists to collaborate more fully in the face of ever greater advancements in ancient DNA research, according to SMU archaeologist David J. Meltzer and his colleagues in a recent article in the scientific journal Science.

The authors write in “A composite window into human history” that over the past decade, DNA testing of ancient human remains has become a valuable tool for studying and understanding past human population histories.

Most notably, for example, is how sequencing of ancient genomes resolved the dispute over our species’ evolutionary relationship with Neanderthals, the authors point out.

Even so, the authors caution that collaboration with archaeologists is key for scientific accuracy as well as navigating ethical implications.

Archaeologists know from the study of artifacts that it isn’t always the case that people who share material culture traits were likewise part of the same biological population.

“One can have similar traits without relatedness, and relatedness without similarity in traits,” say the authors in the article.

At the same time, where there is biological relatedness, cultural relatedness can’t be assumed, nor can language groups indicate that biological populations, material assemblages or even social units are related.

“Geneticists are often keen to use ancient DNA to understand the causes and mechanisms of demographic and cultural change,” the authors write. “But archaeologists long ago abandoned the idea that migrations or encounters between populations are a necessary or sufficient explanation of cultural change.”

The authors make the point that understanding population movements requires broad investigation of many factors, including environmental and social contexts, timing and logistics, how new resources and landscapes were managed, and the transfer of cultural knowledge.

“Hence, it requires evidence for archaeology, paleoecology and other fields to supplement and complement ancient DNA data,” the authors write. “And that entails effective collaboration, one that goes beyond archaeologists serving as passive sample providers.”

Meltzer is Henderson-Morrison Professor of Prehistory in the SMU Department of Anthropology in Dedman College. As a scientist who studies how people first came to inhabit North America, Meltzer in 2009 was elected a member of the National Academy of Sciences in recognition for his achievements in original scientific research. In 2013 he was elected to the American Academy of Arts and Sciences.

Co-authors on the perspective piece with Meltzer were Niels N. Johannsen, Aarhus University, Denmark; Greger Larson, University of Oxford; and Marc Vader Linden, University College London.

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Sapiens: Why the Famous Folsom Point Isn’t a Smoking Gun

A Folsom spear point was discovered between the ribs of an extinct species of bison — but was it really proof that humans had killed the animal?

The research into the arrival of how and when people first arrived in North America by noted SMU archaeologist David J. Meltzer was covered in the online anthropology magazine Sapiens in a column by Stephen E. Nash, science historian and archaeologist at the Denver Museum of Nature & Science.

The article, Why the Famous Folsom Point Isn’t a Smoking Gun, published Aug. 29, 2017.

Meltzer, a member of the National Academy of Sciences and Henderson-Morrison Professor of Prehistory in SMU’s Dedman College of Humanities and Sciences, conducts original research into the origins, antiquity and adaptations of the first Americans.

Paleoindians colonized the North American continent at the end of the Ice Age. Meltzer focuses on how those hunter-gatherers met the challenges of moving across and adapting to the vast, ecologically diverse landscape of Late Glacial North America during a time of significant climate change.

Meltzer’s archaeology and history research has been supported by grants from the National Geographic Society, the National Science Foundation, The Potts and Sibley Foundation and the Smithsonian Institution. In 1996, he received a research endowment from Joseph and Ruth Cramer to establish the Quest Archaeological Research Program at SMU, which will support in perpetuity research on the earliest occupants of North America.

Read the full story.


By Stephen E. Nash

Remember the iconic Folsom point? The one that I said, in my last post, changed the future of archaeology?

To recap: On August 29, 1927, paleontologists from the Colorado Museum of Natural History (renamed the Denver Museum of Nature & Science in 2000) discovered a stone projectile point embedded in the ribs of an extinct form of bison.

After making that discovery in the field, the researchers left the point sitting where it was and immediately sent out a call to their colleagues to come to northeastern New Mexico to see it for themselves. Within two weeks a number of well-known scientists had visited the site, seen the point in position, and established a scientific consensus: Native Americans lived and hunted in North America during the end of the last Ice Age, about 12,000 years ago, far earlier than they were previously thought to be here.

It turns out, though, that the story at the Folsom Site was more complicated than researchers initially believed. So what has changed since 1927? The latest part of the story began 20 years ago.

In 1997, David Meltzer, an archaeologist at Southern Methodist University who studies “Paleoindians,” the earliest inhabitants of North America, began a three-year project at the Folsom Site to reassess and re-excavate the site using modern tools and techniques—which were not available in the 1920s. His goal was to better understand how, and under what conditions, the Folsom Site formed. Meltzer and his team used now-standard excavation-control techniques to record their findings in three-dimensional space and to determine if any unexcavated areas of the site could be found. In so doing, they hoped to find evidence of the Paleoindian campsite that might have been associated with the main bison-kill and butchering site.

As a result of Meltzer’s research, we now know that the bison-kill event occurred in the fall. How do we know? Bison reproduce, give birth, and grow up on a reasonably predictable annual cycle. Meltzer and his colleagues analyzed dental eruption patterns on excavated bison teeth to determine the season of the kill.

The archaeologists also determined that Folsom hunters were experts at their job, having systematically killed and butchered at least 32 bison at the site.

Read the full story.

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A Total Eclipse of the First Day of School

Dedman College, SMU Physics Department host Great American Solar Eclipse 2017 viewing

Thousands of students, faculty and townspeople showed up to campus Monday, Aug. 21 to observe the Great American Solar Eclipse at a viewing hosted by Dedman College of Humanities and Sciences and the SMU Department of Physics.

The festive event coincided with the kick-off of SMU’s Fall Semester and included Solar Eclipse Cookies served while viewing the rare astronomical phenomenon.

The eclipse reached its peak at 1:09 p.m. in Dallas at more than 75% of totality.

“What a great first day of the semester and terrific event to bring everyone together with the help of Dedman College scientists,” said Dedman Dean Thomas DiPiero. “And the eclipse cookies weren’t bad, either.”

Physics faculty provided indirect methods for observing the eclipse, including a telescope with a viewing cone on the steps of historic Dallas Hall, a projection of the eclipse onto a screen into Dallas Hall, and a variety of homemade hand-held devices.

Outside on the steps of Dallas Hall, Associate Professor Stephen Sekula manned his home-built viewing tunnel attached to a telescope for people to indirectly view the eclipse.

“I was overwhelmed by the incredible response of the students, faculty and community,” Sekula said. “The people who flocked to Dallas Hall were energized and engaged. It moved me that they were so interested in — and, in some cases, had their perspective on the universe altered by — a partial eclipse of the sun by the moon.”

A team of Physics Department faculty assembled components to use a mirror to project the eclipse from a telescope on the steps of Dallas Hall into the rotunda onto a screen hanging from the second-floor balcony.

Adjunct Professor John Cotton built the mount for the mirror — with a spare, just in case — and Professor and Department Chairman Ryszard Stroynowski and Sekula arranged the tripod setup and tested the equipment.

Stroynowski also projected an illustration of the Earth, the moon and the sun onto the wall of the rotunda to help people visualize movement and location of those cosmic bodies during the solar eclipse.

Professor Fred Olness handed out cardboard projectors and showed people how to use them to indirectly view the eclipse.

“The turn-out was fantastic,” Olness said. “Many families with children participated, and we distributed cardboard with pinholes so they could project the eclipse onto the sidewalk. It was rewarding that they were enthused by the science.”

Stroynowski, Sekula and others at the viewing event were interviewed by CBS 11 TV journalist Robert Flagg.

Physics Professor Thomas Coan and Guillermo Vasquez, SMU Linux and research computing support specialist, put together a sequence of photos they took during the day from Fondren Science Building.

“The experience of bringing faculty, students and even some out-of-campus community members together by sharing goggles, cameras, and now pictures of one of the great natural events, was extremely gratifying,” Vasquez said.

Sekula said the enthusiastic response from the public is driving plans to prepare for the next event of this kind.

“I’m really excited to share with SMU and Dallas in a total eclipse of the sun on April 8, 2024,” he said.