graduate student research

Research: SMU students discover two new supernovae

SMU graduate student researchers have discovered two new supernovae, and their observations of these massive exploding stars will help improve the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe.

A supernova discovered Wednesday, Feb. 6, 2013 exploded about 450 million years ago, said Farley Ferrante, a graduate student in the Department of Physics who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major, best known for the Big Dipper.

A second supernova discovered Tuesday, Nov. 20, 2012 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment’s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernovae, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet. “That’s fairly recent as these explosions go,” Ferrante said. Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year. Before telescopes, supernovae observations were rare — sometimes only several every few centuries, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Everest and Sherpa are Type 1a supernovae, the result of white dwarf explosions, said Robert Kehoe, physics professor and leader of the astronomy team in the Department of Physics.

The scientists explain that a white dwarf is a dying star that has burned up all its energy. It is about as massive as the Earth’s sun. Its core is about the size of the Earth. The core is dense, however, and one teaspoon of it weighs as much as Mount Everest, Kehoe said.

A white dwarf explodes if fusion restarts by tugging material from a nearby star, according to the scientists. The white dwarf grows to about one and a half times the size of the sun. Unable to support its weight, Kehoe said, collapse is rapid, fusion reignites and the white dwarf explodes. The result is a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

While Sherpa is a standard Type 1a, Everest is peculiar. It exhibits the characteristics of a Type 1a called a 1991T, Ferrante said.

“Everest is the result of two white dwarfs that collide, then merge,” he said.

Like other Type 1a supernovae, Everest and Sherpa provide scientists with a tiny piece to the puzzle of one of the greatest mysteries of the universe: What is dark energy?

Every Type 1a supernova provides astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe. It’s theorized that dark energy explains the accelerating expansion of our universe at various epochs after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

Written by Margaret Allen

> Read more from the SMU Research blog

Students show their work for 2013 SMU Research Day Feb. 27

Researchers in the labSMU graduate students, as well as select undergraduates, from a wide variety of disciplines will share their work today as part of the University’s 2013 Research Day. All SMU faculty, staff members and students are invited to visit the Hughes-Trigg Student Center Ballrooms from 2-4:30 p.m Wednesday, Feb. 27, to meet the student researchers and discuss their results. Refreshments will be served.

Find a list of this year’s participants at SMU News
Visit SMU Graduate Studies online

Research: SMU paleontologist identifies new Texas fossil species

A new species of coelacanth fish has been discovered in Texas. Pieces of tiny fossil skull found in Fort Worth have been identified as 100 million-year-old coelacanth bones, according to SMU paleontologist John Graf.

The coelacanth has one of the longest lineages — 400 million years — of any animal. It is the fish most closely related to vertebrates, including humans.

The SMU specimen is the first coelacanth in Texas from the Cretaceous, said Graf, who identified the fossil. The Cretaceous geologic period extended from 146 million years ago to 66 million years ago.

Graf named the new coelacanth species Reidus hilli. It is now the youngest coelacanth identified in the Lone Star State, a distinction previously belonging to a 200 million-year-old coelacanth from the TriassicReidus hilli is also the first coelacanth ever identified from the Dallas-Fort Worth area.

Coelacanth fossils have been found on every continent except Antarctica. Few have been found in Texas, said Graf, a paleontology graduate student in the Huffington Department of Earth Sciences of SMU’s Dedman College.

The coelacanth has eluded extinction for 400 million years. Scientists estimate it reached its maximum diversity during the Triassic. The fish was thought to have gone extinct about 70 million years ago. However, the fish rose to fame in 1938 after live specimens were caught off the coast of Africa. Today coelacanths can be found swimming in the depths of the Indian Ocean.

“These animals have one of the longest lineages of any vertebrates that we know,” Graf said.

The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.

“What makes the coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land,” he said. “They share the most recent common ancestor with all of terrestrial vertebrates.”

Coelacanths have boney support in their fins, which is the predecessor to true limbs. “Boney support in the fins allows a marine vertebrate to lift itself upright off the sea floor,” Graf said, “which would eventually lead to animals being able to come up on land.”

Written by Margaret Allen

> Read the full story at the SMU Research blog

Tune In: Sharing new knowledge at SMU Research Day 2012

SMU graduate students — and a limited number of undergraduates — presented results of research they have been working on at SMU at the 2012 Graduate Student Research Day. Sponsored by SMU’s Office of Research and Graduate Studies, the event gives participants opportunities to network with students in different programs, to present their work in formats they will use as professionals, and to share the outstanding research being done at the University.

Revisit a few of the nearly 90 presentations in this video by Eva Parks of SMU News. Click the YouTube screen to view, or click this link to watch SMU’s 2012 Research Day video in a new window.

The Guildhall at SMU joins elite Intel university research group

The Guildhall at SMU has received a $50,000 grant from Intel Corporation’s Visual Computing Academic Program for research scholarship funding. SMU students will conduct studies to expand upon applied research pursued within the Intel Science and Technology Centers for Visual Computing (ISTC-VC) and other Intel-supported visual computing academic research.

“We are thrilled to be a part of Intel’s Visual Computing Academic Program and working with the ISTC-VC,” says Peter Raad, founder and executive director of The Guildhall at SMU. “Our Master’s students are creating new worlds through interactive video game development here at SMU. This funding will help us collaborate with Intel and other universities to reach new levels of realism and expand the practical uses for visual computing.”

Intel’s Visual Computing Academic Program was established to accelerate the development of tools and techniques for interactive rendering on highly parallel architectures. The program encourages collaboration between Intel product development teams and elite academic research programs.

“We are excited about the opportunity to work more closely with The Guildhall going forward,” said Intel’s Randi Rost, manager of the Visual Computing Academic Program. “Through this relationship, we will be able to harden, optimize, and polish visual computing research results and incorporate them in game environments. This will provide value to students at the Guildhall, to our visual computing research collaborators, to Intel product development and enabling teams, and ultimately to consumers who use Intel platforms.”

“Having our faculty and students recognized by Intel as key contributors to the future of visual computing is very gratifying.  It will also allow us to collaborate with other great minds at Intel and other universities,” Raad adds.  “We hope to be announcing winners of this year’s research scholarships and their projects soon.”

In this video, James Ohlen, creative director of BioWare Austin, takes a moment at Comic Con 2011 to praise Guildhall alumni involved in the making of the smash hit online game Star Wars: The Old Republic. Click the YouTube screen to view, or click this link to open the James Ohlen video in a new windowvideo

> Visit The Guildhall at SMU online

Students put best work forward during 2012 Research Day Feb. 10

Graduate students present their research during SMU's 2011 Research DayMore than 80 SMU graduate students (and a select number of undergraduates) from a wide variety of disciplines will present their best work today as part of the University’s 2012 Research Day. All SMU faculty, staff members and students are encouraged to visit the Hughes-Trigg Student Center Ballrooms from 2-4:30 p.m Friday, Feb. 10, to meet the student researchers and discuss their results.

> Learn more about this year’s projects from SMU News
> Visit SMU Graduate Studies online

Research Spotlight: Does public insurance provide better care?

In the fierce national debate over a new federal law that requires all Americans to have health insurance, it’s widely assumed that private health insurance can do a better job than the public insurance funded by the U.S. government.

But a first-of-its-kind analysis of newly available government data found just the opposite when it comes to infants covered by insurance.

Among the insured, infants in low-income families are better off under the nation’s government-funded public health insurance than infants covered by private insurance, says SMU economist Manan Roy, the study’s author.

The finding is surprising, says Roy, because the popular belief is that private health insurance always provides better coverage. Roy’s analysis, however, found public health insurance is a better option — and not only for low-income infants.

“Public health insurance gets a lot of bad press,” says Roy. “But for infants who are covered by health insurance, the government-funded insurance appears to be more efficient than private health insurance — and can actually provide better care at a lower cost.

“Private health insurance plans vary widely,” Roy says. “Many don’t include basic services. So infants on more affordable plans may not be covered for immunizations, prescription drugs, for vision or dental care, or even basic preventive care.”

The U.S. doesn’t have a system of universal health insurance. But the Patient Protection and Affordable Care Act signed into law by President Obama on March 23, 2010, requires all Americans to have health insurance. The act also expands government-paid free or low-cost Medicaid insurance to 133 percent of the federal poverty level.

SMU Ph.D. candidate and Adjunct Professor of Economics Manan Roy

“Given the study’s surprising outcome, it’s likely that the impact of national reforms to bring more children under public health insurance will substantially improve the health of infants who are in the worst health to begin with,” says Roy (pictured right). “It’s likely to also help infants who aren’t low-income.”

Roy presented her study, “How Well Does the U.S. Government Provide Health Insurance?” at the 2011 Western Economic Association International conference in San Diego. She is a Ph.D. student and an adjunct professor of economics in SMU’s Dedman College of Humanities and Sciences.

A large body of previous research has established that insured infants are healthier than uninsured infants. Roy’s study appears to be the first of its kind to look only at insured infants to determine which kind of insurance has the most impact on infant health — private or public.

Roy found:

  • Infants covered by public insurance are mostly from disadvantaged backgrounds. Those under Medicaid and its sister program — CHIP — come mostly from lower-income families. Their parents — usually black and Hispanic — are more likely to be unmarried, younger and less educated. Economists refer to this statistical phenomenon — when a group consists primarily of people with specific characteristics — as strong positive or negative selection. In the case of public health insurance, strong negative selection is at work because it draws people who are poor and disadvantaged.
  • Infants on public health insurance are slightly less healthy than infants on private insurance. On average they had a lower five-minute Apgar score and shorter gestation age compared to privately insured infants. They were less likely to have a normal birth weight and normal Apgar score range, and were less likely to be born near term.
  • Infants covered by private health insurance are mostly from white or Asian families and are generally more advantaged. They are from higher-income families, with older parents who are usually married and more educated. Their mothers weigh less than those of infants on public insurance. This demonstrates strong positive selection of wealthier families into private health insurance.
  • Roy then compared the effect of public insurance on infant health in relation to private health insurance. To do that, she used an established statistical methodology that allows economists to factor negative or positive selection into the type of insurance. In comparing public vs. private insurance — allowing for strong negative selection into public health care — a different picture emerged.

“The results showed that it’s possible to attribute the entire detrimental effect of public health insurance to the negative selection that draws less healthy infants into public health insurance,” Roy says.

Written by Margaret Allen

> Read the full story at the SMU Research blog

Research Spotlight: CERN scientists close in on Higgs boson

An event showing four muons (red tracks) from a proton-proton collision in ATLAS. This event is consistent with two Z particles decaying into two muons each. Such events are produced by Standard Model processes without Higgs particles. They are also a possible signature for Higgs particle production, but many events must be analyzed together in order to tell if there is a Higgs signal. (Image courtesy of CERN.)

In a giant game of hide and seek, physicists say there are indications they finally may have found evidence of the long sought after fundamental particle called the Higgs boson.

Researchers at Switzerland-based CERN, the largest high-energy physics experiment in the world, have been seeking the Higgs boson since it was theorized in the 1960s. The so-called “God” particle is believed to play a fundamental role in solving the important mystery of why matter has mass.

Thousands of scientists from around the world seek evidence of the Higgs particle through experiments at CERN’s Large Hadron Collider. The researchers analyze a flood of electronic data streaming from the breakup of speeding protons colliding in the massive particle accelerator. Scientists on Tuesday announced in a seminar held at CERN that they’ve found hints of the Higgs.

SMU physicist Ryszard Stroynowski“Now we have a strong indication, but not yet a confirmation, of a discovery,” said SMU physicist Ryszard Stroynowski (left), the leader of SMU’s team of scientists working on the experiment.

Theorists have predicted that some subatomic particles gain mass by interacting with other particles called Higgs bosons. The Higgs boson is the only undiscovered part of the Standard Model of physics, which describes the basic building blocks of matter and their interactions.

Higgs bosons, if they exist, are short-lived and can decay in many different ways. Just as a vending machine might return the same amount of change using different combinations of coins, the Higgs can decay into different combinations of particles. Discovery relies on observing statistically significant excesses of the particles into which they decay rather than observing the Higgs itself.

“If indeed we are able to confirm sighting of the Higgs in the months ahead, this clearly focuses our future studies,” said Stroynowski, a professor in the SMU Department of Physics. “Now by the middle of next year we’ll know for sure if this particle exists and we can begin to study its properties. This is a very big step in the understanding of particle physics.”

Besides Stroynowski, the SMU team of researchers includes three other Physics Department faculty: Jingbo YeRobert Kehoe and Stephen Sekula, six postdoctoral fellows and five graduate students. Main contributions to the new analysis of the data were made by postdoctoral researcher Julia Hoffman and graduate student Ryan Rios.

Others in the department who have contributed include former postdoctoral fellow David Joffe, now an assistant professor at Kennesaw State University, graduate students Renat Ishmukhametov and Rozmin Daya and theoretical faculty Fredrick Olness and Pavel Nadolsky.

Stroynowski, Hoffman, and Rios are among the more than 70 scientists whose work directly contributed to the conference papers reporting the findings, said Olness, a professor and chairman of the SMU Department of Physics. While thousands of scientists worldwide participated directly and indirectly in the experiments, SMU is one of only a few U.S. universities whose scientists are named among the 70 researchers directly cited on one of the three conference papers.

“SMU’s role in the LHC experiments provides our students a chance to participate in pioneering discoveries,” Olness said. “SMU students helped build the ATLAS detector, they were in the control room when the experiment started up, and they contributed to the analysis. The results presented today are historic, and they will help shape our view of the matter and forces that comprise our universe; SMU students have played a role in this achievement.”

SMU's Ryszard Stroynowski and Ryan Rios

In Fondren Science Building, physicist and SMU Physics Professor Ryszard Stroynowski and physics graduate student Ryan Rios discuss the Higgs boson after viewing a CERN web cast Tuesday announcing evidence of the Higgs. (Photo by Hillsman S. Jackson.)

Discovering the type of Higgs boson predicted in the Standard Model would confirm a theory first put forward in the 1960s.

“This year, the LHC has come roaring into the front of the hunt for the Higgs boson and may be poised to either identify it, or refute its existence, in the coming months,” said Kehoe, associate professor in the SMU Department of Physics. “As I like to tell my students learning modern physics, ‘You still live in a world in which we do not know for sure the mechanism breaking the symmetry between electromagnetic and weak interactions. That world may be soon to change forever. We may soon see a truly new thing.’”

– Written by Margaret Allen

> Read the full story at the SMU Research blog

Research Spotlight: Seeking solutions for unsafe water

Supported by a $270,000 grant from the United Nations High Commissioner for Refugees and additional SMU funds, faculty member Andrew Quicksall and his graduate students in the University’s Lyle School of Engineering are collecting water samples in UNHCR refugee camps, bringing samples back to SMU for analysis, and training workers in and around the camps to test water supplies.

The group will integrate information from multiple sources to develop a database that will help UNHCR planners provide safer drinking water in existing and future camps.

“They’ve asked us to build out a whole picture, truly worldwide, for what’s in the drinking water in refugee camps,” said Quicksall, J. Lindsay Embrey Trustee Assistant Professor in the Lyle School. “So we’re going to go on-site, collect water, analyze some in the field and bring quite a bit of water back to our SMU laboratories and get a full picture.”

The database developed by Quicksall’s group will identify contaminants in drinking water and allow UNHCR officials to track water quality in the camps over time. Some water quality problems are indigenous to the regions where the camps are situated, some develop over time, and some are the nearly instant consequence of thousands of people collecting in unsuitable locations to escape war and famine faster than sanitary infrastructure can be built.

For example, the agreement with UNHCR commits Quicksall’s team to investigate critical water issues in Dadaab, Kenya – home to the largest refugee complex in the world. Nearly half a million people are concentrated in three camps there, many living in makeshift shelters of twigs, reeds and scraps. Refugees pouring across the border to escape war and famine in Somalia continue to face shortages of food, water, shelter and sanitation hazards there.

“The technical challenges of supporting refugee populations of this size will require that our teams stay engaged with the UNHCR for years to come,” said Geoffrey Orsak, dean of the SMU Lyle School of Engineering. “Fortunately, our new Hunt Institute for Engineering and Humanity makes it possible to lead efforts of this magnitude nearly anywhere on the globe.”

Some camps have safe drinking water available, but the taste is so off-putting that residents seek out other sources. In Nakivale, Uganda, for example, the high iron content in well water drives refugees to drink surface water that is frequently contaminated with coliform bacteria. Quicksall’s group also will investigate methods of improving the taste of such safe, but unpalatable, drinking water.

Preliminary research results have revealed problematic concentrations of iodide in drinking water at Dadaab and fluoride in both Southern Uganda and Kakukma, Kenya. Some types of contaminants may not create problems short-term, Quicksall explains, but create severe health issues for people over the long term – particularly children and the elderly. His study group will have the opportunity to both recommend and implement remediation methods for those problem water sources, he said.

“To work with the science in the lab and see it applied internationally — I don’t think there is an opportunity like this anywhere else,” said graduate student Drew Aleto, a member of Quicksall’s study team.

Written by Kimberly Cobb

> Read the full story at the SMU Research blog

Research Spotlight: Bamboo tool-making study shines light on East Asia’s Stone Age tool scarcity

The long-held theory that prehistoric humans in East Asia crafted tools from bamboo was devised to explain a lack of evidence for advanced prehistoric stone tool-making processes. But can complex bamboo tools even be made with simple stone tools? A new study suggests the “bamboo hypothesis” is more complicated than conceived, says SMU archaeologist Metin I. Eren.

Research until now has failed to address a fundamental question: Is it even possible to make complex bamboo tools with simple stone tools? Now an experimental archaeological study – in which a modern-day flint knapper replicated the crafting of bamboo knives – confirms that it is possible to make a variety of bamboo tools with the simplest stone tools.

However, rather than confirming the long-held “bamboo hypothesis,” the new research shows there’s more to the theory, says Eren, the expert knapper who crafted the tools for the study.

The researchers found that crudely knapped stone choppers made from round rock “cobbles” performed remarkably well for chopping down bamboo. In addition, bamboo knives were efficiently crafted with stone tools. While the knives easily cut meat, they weren’t effective at cutting animal hides, however, possibly discouraging their use during the Stone Age, say the authors. Some knives made from a softer bamboo species entirely failed to produce and hold a sharp edge.

“The ‘bamboo hypothesis’ has been around for quite awhile, but was always represented simply, as if all bamboo species, and bamboo tool-making were equal,” says Eren, a doctoral candidate in anthropology in SMU’s Dedman College of Humanities and Sciences. “Our research does not debunk the idea that prehistoric people could have made and used bamboo implements, but instead suggests that upon arriving in East and Southeast Asia they probably did not suddenly start churning out all of their tools on bamboo raw materials either.”

The findings appear online in the article “Were Bamboo Tools Made in Prehistoric Southeast Asia? An Experimental View from South China,” which will be published in an issue of the journal Quaternary International, edited by Parth Chauhan and Rajeev Parnaik.

To observe the process of using simple stone tools to make a bamboo knife, watch this video made by the researchers.

> Get the full story from the SMU Research blog

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