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Dark matter search may turn up evidence of WIMPS: SMU Researcher Q&A

Radioactivity interferes with our ability to observe dark matter. A banana would be more radioactive than the materials we use for our experiment. — Jodi Cooley

The XIA Alpha Particle Counter sounds like it belongs in a science fiction movie. In reality it’s housed in a clean room operated by SMU’s Department of Physics, where SMU physicist Jodi Cooley and her students rely on it as part of their search for dark matter.

Cooley is a member of the global scientific consortium called SuperCryogenic Dark Matter Search (SuperCDMS). SuperCDMS is searching for elusive dark matter — the “glue” that represents 85 percent of the matter in our universe but which has never been observed.

SuperCDMS operates a particle detector in an underground abandoned mine in Minnesota. The detector is designed to capture a glimpse of WIMPS (Weakly Interacting Massive Particles), which some physicists theorize constitutes dark matter. WIMPS are particles of such low mass that they rarely interact with ordinary matter, making them extremely difficult to detect.

Now SuperCDMS plans to build a larger and even more sensitive detector for deployment at SnoLab, an even deeper underground mine near Ontario, Canada. To prepare, Cooley’s team will advance analysis techniques and help determine ultra pure construction materials to increase the detector’s sensitivity to dark matter interactions.

In testing materials, Cooley’s team measures how much radon or radioactivity occurs as background interference on a sample. SuperCDMS scientists try to minimize background interference to improve the chances of observing WIMPS.

To assess background, Cooley and her team rely on the high-tech XIA Alpha Particle Counter. SMU is one of only five entities in the world to house the XIA.

An assistant professor in the SMU Department of Physics, Cooley was recently recognized by the National Science Foundation with its prestigious Faculty Early Career Development Award. The NSF awarded Cooley a 5-year, $1 million research grant toward her SuperCDMS dark matter research. Students assisting in the XIA counting include Bedile Karabuga, doctoral student, and Mayisha Nakib, first year.

What’s the importance of background?
Cooley:
For people who are older, they’ll remember back before digital TVs to analog TVs. Sometimes you’d turn to a channel and it would be fuzzy, so you’d play with the antenna, play with the contrast. That’s sort of the same thing going on in our detectors.

We want our detectors to produce a clear image of dark matter. But we have a lot of background or static and fuzz getting in the way. So we have a bag of tricks for removing that static or fuzz to help us see if the dark matter interacts in our detectors.

Just like the TV, we don’t want to start with a channel that’s completely snow, but a channel that’s sort of coming in. You want to reduce the background as much as possible. That’s what we’re doing with SuperCDMS. So the studies we’re doing are trying to reduce the background around the instrument by selecting ultra pure material with which to construct the instrument.

The background is from radioactivity, cosmic rays, and just from the fact there are particles around us all the time. So we try to minimize them as much as possible. Even our finger essentially would introduce radioactivity onto our detectors.

How important are ultra pure materials?
Cooley:
This is very critical. We’re looking for a very rare occurrence: dark matter interacting in these detectors. Radioactivity interferes with our ability to observe dark matter. The radioactivity in most materials is much higher than the rate of dark matter interactions. So we try to get the purest materials we can find. To describe how pure a material we’re seeking, it helps to know that a banana would be more radioactive. Touching the detectors with our fingers, because our fingers have potassium on them, would ruin the experiment. We’re looking for very trace levels of radioactivity in materials.

To select the best, we try to count the rate of radioactive decays in materials. Our SuperCDMS collaboration has several types of counters, and different ways and techniques to calculate a material’s radioactivity. Here at SMU in the LUMINA Lab — Laboratory for Ultra Pure Material Isotope and Neutron Assessment — we have the XIA counter, which we’ve named Peruna.

Where do neutrons enter the picture?
Cooley:
Neutrons are nearly impossible to distinguish from dark matter in our detectors. They also form background. My postdoctoral researcher Silvia Scorza and SMU graduate student Hang Qiu are both characterizing neutrons that come from the materials. That’s primarily done through simulations. So once we have rates of these types of interactions, we can generate through simulations what this would mean for the experiment. That helps us determine the right materials.

How does the XIA work?
Cooley:
The instrument is essentially a drift chamber. We put a material sample on the surface of a tray in the chamber. An electric field goes through the instrument. When the charged particles give off radioactivity in the electric field they drift upward, and then we can measure the energy of the particles and the number of them from any given sample.

Can that be challenging?
Cooley:
It’s not trivial. There are subtleties in the instrument. In trying to understand the data and trying to get an accurate count off certain types of materials such as plastics, we have to decide on certain conditions, like how long should the purging process last.

Why is there more than one dark matter experiment in the world?
Cooley:
Dark matter is an important question and there are a variety of experiments using different techniques to solve the question. It’s not enough for one technique and one experiment to say they’ve made a discovery. It always has to be verified and looked at by another experiment, independently, with a different technique. If different techniques and different instruments prove the finding, then you can have a lot more confidence in the result. — Margaret Allen

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SMU News: 2012 Research Day at Southern Methodist University

SMU News covered the annual 2012 Research Day on Feb. 10 where SMU graduate and undergraduate students presented results of their research studies.

Sponsored by SMU’s Office of Research and Graduate Studies, the event sought to foster communication between students in different programs, give students the opportunity to present their work in formats they will use as professionals, and to share with the SMU community and others the outstanding research being done at the University.

The students presented their studies on posters, and were available to discuss their findings and the significance of the research.

Read the full story.

EXCERPT:

Among the projects at the event were:

  • Psychology student Vanessa Rae Stevens (under Professor Alicia Meuret) is studying whether people with tattoos and body piercings are also prone to intentional self injury by cutting, scratching, burning, etc.
  • Psychology student Grant Holland (under Professor George Holden) is studying recordings of interactions between mothers and their children with an eye toward better understanding the effects of tone-of-voice on behavior at bedtime.
  • Statistics student Holly Stovall (under Professor Lynne Stokes) is examining how to more precisely measure success in teaching programs for No Child Left Behind.
  • Earth sciences student Mary Milleson (under Professor Neil Tabor) is using core samples taken from Dallas’s White Rock Lake to gain a better understanding of how the growing urbanization of the area over the last 100 years is affecting the lake.
  • Computer science student Ruili Geng (under Professors Jeff Tian and Liguo Huang) is researching how to make the performance of the web and cloud computing more dependable.
  • Physics students Bedile Karabuga and Mayisha Zeb Nakib (under Professor Jodi Cooley-Sekula) are examining a specific technique for identifying dark matter.
    For more information, contact the Office of Research and Graduate Studies at 214-768-4345 or smugrad@smu.edu.

Read the full story.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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National Geographic: Andrés Ruzo, geothermal researcher

National Geographic has launched its new Explorers web site, which includes SMU graduate student Andrés Ruzo.

The Explorers site acknowledges the work of the world’s scientists whose research is made possible in part through funding from National Geographic.

In a video description of the site, National Geographic explains: “In 1888 a club was formed, with a mission to explore. Today that spirit lives on in a new generation of National Geographic explorers. Innovative thinkers who redefine exploration. Living the mission and making the world a better place.”

Ruzo is a graduate student in Roy M. Huffington Department of Earth Sciences in Dedman College of Humanities and Sciences.

His focus is developing geothermal fields and technologies throughout the Americas, including collecting data to develop a geothermal map of Peru.

Read the National Geographics’ Q&A with Ruzo.

EXCERPT:

What did you want to be when you were growing up?
For me, it was never what I wanted to be, but rather what I wanted to do with my life. I’ve wanted to be just about everything from a zoologist to an actor to a diplomat, and even a monk. However, what I want to do with my life has never changed: I want to be a force of positive change in the world.

How did you get started in your field of work?
There is really no exact start, but rather, a lifetime of small coincidences that have led me to the world of geothermal energy.

As a boy I would spend my summers on the family farm in Nicaragua, which rests on top of a volcano called the Casita Volcano. I was able to see firsthand the power of the Earth’s heat. Later, as an undergrad at Southern Methodist University (SMU), these childhood memories inspired me to take a volcanology class. The first time I opened my class textbook, there on the page was a photo of the Casita Volcano! This created a personal connection with the subject that awakened my passion for geology. My desire to learn more about the Earth’s heat, and how we can harness it for power, eventually led me to the SMU Geothermal Lab, where I have studied, researched, and pursued my career in geology for the past six years.

What inspires you to dedicate your life to energy issues?
Energy can turn deserts into fertile cropland, alleviate the struggle for resources, and permit seven billion people to live longer, healthier, more comfortable lives. Simultaneously, a nation’s economic and environmental prosperity, as well as its international power, are also tied with how that nation uses and creates energy.

Energy is a kingpin problem. By solving our energy issues, we simultaneously take care of other major world problems. The way I see it, by dedicating myself to energy, I am also fighting for the environment, national security, international relations, overpopulation, and economic problems, to name a few.

Although energy can do all of this, it often comes at a cost to our health and environment. This is where green energy comes in. Although I support all green energy development and believe that the right answer lies in developing local resources, given its base-load nature and its tremendous potential synergy with the oil and gas industry, I believe geothermal is the energy world’s sleeping giant.

Good business sense and good environmental practices do not have to be mutually exclusive. It is our job as consumers to ensure that the market demands both practices from corporations. I see geothermal as the best way to reach this end, so it is easy to want to dedicate my life to it—one solution that solves multiple problems.

Read the National Geographics’ Q&A with Ruzo.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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National Geographic: Louis Jacobs, vertebrate paleontologist

National Geographic has launched its new Explorers web site, which includes SMU paleontologist Louis L. Jacobs.

The Explorers site acknowledges the work of the world’s scientists whose research is made possible in part through funding from National Geographic.

In a video description of the site, National Geographic explains: “In 1888 a club was formed, with a mission to explore. Today that spirit lives on in a new generation of National Geographic explorers. Innovative thinkers who redefine exploration. Living the mission and making the world a better place.”

A professor in Dedman College‘s Roy M. Huffington Department of Earth Sciences, Jacobs joined SMU’s faculty in 1983.

Currently his field projects include work in Mongolia and Angola. His book, “Lone Star Dinosaurs” (1999, Texas A&M University Press) was the basis of an exhibit at the Fort Worth Museum of Science and History that traveled the state. He consulted on the new exhibit, Mysteries of the Texas Dinosaurs, which opened in 2009.

Jacobs co-leads Projecto PaleoAngola, a collaborative international scientific research program focused on the ancient life of Angola.

Besides the discovery of the first dinosaur of Angola, the team has uncovered mosasaurs, plesiosaurs, turtles and other Cretaceous marine animals, but the aim is also to create a strong and lasting institutional and scientific collaboration that has a multiplier effect in Angolan academia.

In the laboratory, Jacobs’ research utilizes advanced imaging and stable isotope techniques to investigate paleoenvironmental, biogeographic and phylogenetic issues of the Mesozoic and Cenozoic eras.

Read the National Geographics’ Q&A with Jacobs.

EXCERPT:

What did you want to be when you were growing up?
I always wanted to be a scientist. I did not care what kind because I liked it all. Looking back, although neither of my parents was a scientist, I think they guided me when I was young and I never got off the track. I am very grateful for that.

How did you get started in your field of work?
I always liked the out-of-doors and I liked everything about animals. As a kid, we had a retired geologist as a neighbor who taught me about fossils and showed me how to tie a diamond hitch on a pack mule using a sawhorse. As an undergraduate, I was most interested in the physiology of invertebrates, such as deep-sea vent worms, which were just being discovered at the time. When I went to graduate school, I decided that the most important subject for me is evolution, the unifying concept that links disparate facts about life into a coherent whole. I studied paleontology because fossils link Earth and life, and you can hold them in your hand. I still get a thrill every time I do. I was guided in paleontology by Everett Lindsay, George Gaylord Simpson, and Edwin Harris Colbert.

What inspires you to dedicate your life to vertebrate paleontology?
There is no more all-encompassing science than paleontology because no other subject melds life and Earth in such multifaceted and grand ways. Almost every technique used to study life today, and almost every technique used to study Earth, has an application in paleontology. It is ever refreshing and always interesting because the evolution of life on Earth ultimately leads to us and to all other species living here and now. Thus, our understanding of the relationships between Earth and the life it bears is fundamentally important to our future.

What’s a normal day like for you?
Every day is a collection of new challenges.

Do you have a hero?
Every person who does the best that can be done with honor and dignity is my hero.

What has been your favorite experience in the field? The most challenging?
My favorite experience is usually the one I am having at the time. Most recently it was standing in southern Angola, my feet set on the crystalline rocks of the African continent, looking west over the fault that marked the edge of the rift valley that widened during the past 100 million years to become today’s South Atlantic Ocean. It is like being part of the most obvious icon in earth sciences, the breaking of the puzzle-like fit of South America and Africa. We, Projecto PaleoAngola, are the first paleontologists to look at the coast of Angola with “plate-tectonic eyes,” to collect beautiful fossil vertebrates in abundance, and to investigate the history of life along the shores of this growing ocean.

Read the National Geographics’ Q&A with Jacobs.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Public health insurance provides insured infants better, less costly care than private plans

Surprising result from first-of-its-kind study builds on earlier research that found public health insurance coverage is more comprehensive and costs less than private plans

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 economist and study author Manan Roy, Southern Methodist University, Dallas. The finding emerged from an analysis that was weighted for the fact that less healthy infants are drawn into public health insurance from birth by its low cost.

SMU Researcher to study human-fire-climate interactions

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.”

Why?

“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.

“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,” Roy says. “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, San Diego. Roy is a Ph.D. student and an adjunct professor in SMU’s Department of Economics.

Study weighted to account for less healthy infants in public health insurance
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.

In fact, in a most striking revelation, allowing for a modest to significant amount of negative selection of infants into public health insurance, Roy’s findings suggest that among the insured population of infants, private health insurance is detrimental to child health.

“The real surprise with these findings is that despite a less healthy population — due to the negative factors created by poverty — public health insurance is actually improving the health of these infants,” Roy says.

Public health insurance provides more comprehensive benefits
The findings are less surprising upon deeper analysis.

  • A previous study by the nonpartisan Center on Budget and Policy Priorities sheds light on Roy’s research. That group found that public health insurance provides more comprehensive benefits than private insurance. For example, all children on Medicaid and CHIP receive preventive and primary medical care, inpatient and outpatient care, pediatric vaccines, laboratory and X-ray services, prescription drugs, immunizations, and dental, vision and mental health care coverage.
  • The Medical Expenditure Panel Survey collected by the U.S. Department of Health and Human Services found that on a per person basis, government-provided health insurance for children under 4 years old is cheaper on average compared to private health insurance plans.

“Enrollees in private health insurance can choose from a wide variety of plans,” Roy says. “Those who cut their costs by purchasing less coverage are reducing their access to quality care, including basic services like preventive care, prescription drugs, and vision and dental care.”

Roy says she can only speculate why infants from advantaged and disadvantaged families differ in their health outcomes. It’s possible that infants from families that are better off have access to better nutrition, a healthier lifestyle and possibly safer, cleaner neighborhoods than those from poorer backgrounds.

“Poor families and their infants may be subsisting on cheap food, for example, which tends to be fatty and less nutritious,” Roy says, “and that translates to worse health.”

Study relied on new U.S. government data on thousands of infants
Roy’s statistical analysis drew on data from more than 7,500 infants born in 2001. The data were the most recent available from the Early Childhood Longitudinal Study-Birth Cohort, released by the National Center for Education Statistics, U.S. Department of Education.

The Early Childhood Longitudinal Study follows children born in the United States from birth through the start of kindergarten. Children are from diverse socioeconomic and racial/ethnic backgrounds. Data were gathered from parents, teachers and providers of child care and early education.

Data collected cover children’s health, care, education and cognitive, social, emotional and physical development over time. Included are standard infant health measures like length, infant weight, five-minute Apgar score, and the number of weeks the child was in the womb, which is considered an indicator of birth weight.

Poor families living at or below 185 percent of the federal poverty level represented 49 percent of Roy’s data set.

Demand for public health insurance has increased during the past decade, says Roy, while demand for private insurance has declined. Specifically, between 1999 and 2009 there was an increase in the overall proportion of children under 3 years of age who were insured. Of those, the proportion covered by private insurance declined. The proportion covered by public health insurance increased.

Other researchers have firmly established that infants who are covered by health insurance have timely access to quality care, Roy says. Expanding access could reduce, for example, the number of infants born with low birth weight, which is associated with chronic medical diseases like diabetes, hypertension and heart disease in adulthood. Low birth weight also has been linked to lower average scores on tests of intellectual and social development.

The United States has the highest infant mortality rate among developed nations due to low birth weight and is the only industrialized nation without universal health insurance. The U.S. Supreme Court has agreed to hear a legal challenge to the Obama administration’s new law requiring everyone have health insurance. — Margaret Allen

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.