Star

Recommendations

Info

The San Juan Daily <strong>Star</strong> Monday, March 21, 2015 26 SCI & TECH Fossil Hints T. Rex Got Smart Before It Got Big An artist’s conception of Timurlengia euotica, a smaller and earlier cousin of Tyrannosaurus rex. By KENNETH CHANG At the end of the dinosaur age, Tyrannosaurus rex was a behemoth killer animal, up to 40 feet long and weighing several tons — the top carnivore in the food chain. The very first tyrannosaurs, which arose about 100 million years earlier, were small, about the size of a person. The evolutionary jump of tyrannosaurs from people- and horse-size to behemoths has remained a mystery. A recent fossil finding in Uzbekistan is providing paleontologists with a missing link in the lineage: They have discovered a tyrannosaur with many of the giant’s characteristics — but not its stature or heft. “It has long been thought that tyrannosaurs were such successful predators, in part, because of their large brains and ears well-attuned to low-frequency sound,” said Stephen L. Brusatte, a paleontologist at the University of Edinburgh in Scotland and lead author of a paper published Monday in Proceedings of the National Academy of Sciences, describing the new dinosaur. “The new Uzbek tyrannosaur has basically the same brain as T. rex — same shape, proportions, etc. — just smaller.” The finding, he said, is a new indication that tyrannosaurs got smart before they got big. “It is one of the closest cousins of T. rex and tells us that tyrannosaurs evolved sophisticated brains and senses before they became colossal apex predators,” Dr. Brusatte said. When the first tyrannosaurs evolved, about 170 million years ago, they lived in the shadows of larger meateaters like Allosaurus. For tens of millions of years, tyrannosaurs remained small. And because few rocks of the age 100 million years to 80 million years old are now lying exposed or at the surface anywhere in the world, few clues exist to explain how the early tyrannosaurs evolved into large animals like T. rex. “The fossil record just stops,” Dr. Brusatte said. “We don’t know what goes on in that time.” Before the gap, all tyrannosaurs were small. After the gap, none were. Tyrannosaurus rex and its relatives weighed one ton or more. A CT scan of the Timurlengia fossil showed details about the brain and inner ear. Uzbekistan is one of the few places with geological formations that fall in that 20-million-year gap. Beginning in 1997, Hans-Dieter Sues, chairman of the paleobiology department at the Smithsonian’s National Museum of Natural History, and Alexander O. Averianov, a senior scientist at the Russian Academy of Sciences, organized fossil-collecting expeditions to the Kyzylkum Desert in northern Uzbekistan. The paleontologists uncovered some scattered bones of what appeared to be tyrannosaurs, but the key finding came in 2004 when they found the part of the skull surrounding the brain. “The braincase proved to be the Rosetta stone for the whole thing,” Dr. Sues said. Dr. Brusatte, an expert on tyrannosaurs, was visiting Dr. Averianov a couple of years ago to study some other fossils. “He pulled open a box and pulled out this object about the size of a grapefruit,” Dr. Brusatte recalled. “And he handed it to me and said, ‘You know, what do you make of this?’ ” Dr. Brusatte joined an international team of researchers, including Dr. Sues and Dr. Averianov, in the analysis of the new tyrannosaur. Named Timurlengia euotica, the dinosaur lived about 90 million years ago, right in the middle of the fossil gap. (Timurlengia was named after a Central Asian warlord, Timur; euotica roughly means “well eared.”) Based on a few scattered bones, the scientists estimated that Timurlengia was about the size of a horse, like earlier tyrannosaurs, weighing about 600 pounds, with long legs and bladelike teeth. Lithe and fast, it probably chased down plant eaters like early duck-billed dinosaurs also found in the region. But a CT scan of the braincase showed that the shape of the brain was similar to that of the later tyrannosaurs, and that the inner ear structure was tuned to low frequencies. “We were very surprised it already had this sensory organization associated with T. rex and related animals,” Dr. Sues said. Timurlengia does not explain why tyrannosaurs got big, but Dr. Sues said he suspected that an unusually warm climate, one of the warmest in Earth’s history, had played an important role. Allosaurus and its relatives did not adapt and died out, and then tyrannosaurs grew in size to replace them. So far, Timurlengia is just one clue. It is possible, for instance, that larger tyrannosaurs had already evolved elsewhere. “Like at a murder scene,” Dr. Brusatte said, “one clue is better than none.” A tyrannosaur from China named Xiongguanlong, imprecisely dated to 100 million to 120 million years ago, is another important clue. “At a glance, Xiangguanlong looks to my eye like an advanced tyrannosaur,” said Thomas Carr, a paleontologist at Carthage College in Kenosha, Wis., who has examined the braincase fossil. “This is what this work is all about, completing that evolutionary narrative,” Dr. Carr said. “At the end of the day, there’s much more to discover. It’s still a great leap from Timurlengia to T. rex.”
The San Juan Daily <strong>Star</strong> Monday, March 21, 2016 27 HEALTH 1% Chance of Microcephaly in Zika Outbreak, Scientists Estimate Study suggests relatively low risk of birth defect but big numbers as virus spreads. by Beth Mole Based on data from a past Zika outbreak, researchers estimate that there’s a one-in-100 chance that women infected during the first trimester will give birth to a baby with microcephaly—a birth defect that leaves infants with small and malformed brains and skulls. There’s still not a definitive link between microcephaly and the mosquito-borne virus, which is currently blazing through Central and South America. But the data coming in has only strengthened the connection. For instance, a recent study found that Zika virus can kill off developing brain cells. With the new estimate on the rate of microcephaly in Zika infections from an outbreak in French Polynesia starting in 2013, researchers are relieved that it appears the birth defect is relatively rare. “It means you have a 99 percent chance of having a normal baby,” Dr. Laura Rodrigues, a professor of infectious disease epidemiology at the London School of Hygiene & Tropical Medicine, told The New York Times. By contrast, birth defects from other in utero viral infections can have far steeper risks. Pregnant women infected with the rubella virus, for example, have at least a 38 percent chance of having a baby with congenital rubella syndrome, which can lead to heart disease, developmental delays, and hearing loss. To come up with an estimate for Zika, researchers sifted through medical records from the outbreak of Zika in French Polynesia between 2013 and 2015, which sickened 66 percent of the 270,000 residents. The researchers also established the baseline of microcephaly in the population, which was two cases in 10,000 births. During the outbreak, there were eight total cases, the researchers reported recently in The Lancet. While the rate is relatively low, health experts are not sure if it would be the same in different populations. Even if it is, the virus is still spreading to millions throughout the dozens of countries. “If you apply a one percent risk to a large number of women, it’s still a large public health problem,” said Simon Cauchemez, the study’s lead author and the director of mathematical modeling for the infectious diseases unit at the Pasteur Institute in Paris. Women Who Brought Zika Fears Home With Them By LAURA BEIL In December, Ami Levy and her husband, Jason, left frigid Washington, D.C., for a two-week vacation in Argentina. Once there, they headed north to the Brazilian border for a couple of days, lured by Igauzu Falls. She recalls the excitement when their phones’ GPS indicated they finally were in Brazil, and the awe-inspiring walls of water, some more than 24 stories tall. And, she remembers, everywhere there were mosquitoes, leaving bites on her thigh. Back home the first week of January, Ms. Levy learned she was four weeks pregnant. Her first pregnancy had ended in miscarriage in September, so it was with some hesitation that she left for another trip, this time to Puerto Rico for a rendezvous with her aunt and sister. As soon as she arrived, local news broadcasts began warning pregnant women about the dangers of infection with the Zika virus, carried by mosquitoes and suspected of causing devastating birth defects in infants born to infected women. She booked the first available flight home. “I was on the beach for a few hours and didn’t put on any bug spray,” said Ms. Levy, a 35-year-old psychotherapist. “I had two bites when I got home Sunday.” “I think I would have been more panicky if I hadn’t told myself I needed to keep it together for my baby.” The Zika virus is not yet known to be circulating in the continental United States. But already, fear of the infection has come home for many pregnant women and their families who journeyed abroad before the risks were known. The Centers for Disease Control and Prevention recently reported that nine pregnant women were known to have become infected while traveling. Yet many more are coping with the possibility of exposure, reaching out to their doctors for blood tests and ultrasounds, obsessing on news coverage and trying to manage their worry. The C.D.C. recommends that pregnant women receive blood tests two to 12 weeks after travel to an affected area to detect whether they may have been infected with the Zika virus. Those who may have been exposed are urged to consider having extra ultrasounds to look for birth defects in the developing fetus. Nothing is guaranteed; the antibody test has its limits. Ultrasounds often do not detect fetal microcephaly, the disease causing misshapen heads and brain damage that has been linked to infection with the virus. According to the C.D.C., the scans are most accurate at the end of the second trimester or early in the third. “The risk is small, but the effects are tragic,” said Craig Forest, 37, an associate professor of bioengineering at Georgia Tech in Atlanta. He and his wife, Roxanne, 32, spent Christmas vacation in Costa Rica just as she was entering her second trimester of pregnancy. They chose that destination because of all the countries in the region, it seemed to offer the safest environment for a pregnant woman. After 10 days of rain forest hikes and lazy sunsets on the beach, Ms. Forest was covered with insect bites. Back home in January, the couple began hearing news reports about the Zika virus. Costa Rica was not mentioned. “I’m looking at the list and thinking, ‘That’s all of Costa Rica’s neighbors; we dodged a bullet on that one,’ ” Mr. Forest said. On Feb. 1, Costa Rica was added to the list of countries in which Zika is circulating. The virus had been in the country since at least December. Ms. Forest’s doctor did not order a blood test for the infection, because she had not had any symptoms. Her most recent ultrasound appeared normal, and the couple say they will ask for another at the cutoff time for an abortion. They have lain in bed at night discussing the possibility, something that would have been unthinkable a couple of months ago. They know the risks are remote — first that she might have been bitten by an infected mosquito, and second that the infection might lead to a birth defect. “As analytically minded people, we’re trying to calculate the odds,” said Ms. Forest, who is also an engineer. But when they try to figure the likelihood of a birth defect related to the Zika virus, all they can come up with is “not zero.” There is nothing to do but wait. “I actually tried to stop reading the news,” Ms. Forest said. Even when a pregnant woman is found to have been infected, tests of blood or amniotic fluid cannot definitively tell if the fetus was affected, said Dr. W. Ian Lipkin, an expert in infectious diseases at Columbia University’s Mailman School of Public Health, who is working to develop a more reliable alternative. Microcephaly seems to be a relatively rare complication. But it’s also possible that the virus may cause “more subtle damage that we can’t yet appreciate,” Dr. Lipkin said. Sydney Silverstein, 35, an Emory University doctoral candidate, has been living in Iquitos, Peru, since July. She is eight and a half months pregnant. There is no widespread epidemic of Zika virus in Peru, but the virus is present in Lima. Moreover, she spent time on the Brazilian border in late fall, early in her pregnancy. She has had extra ultrasound scans from her doctor, and her fetus looks unaffected.
Page 1 and 2: San The Juan Monday, March 21, 2016
Page 3 and 4: GOOD MORNING The San Juan Daily Sta
Page 5 and 6: The San Juan Daily Star Monday, Mar
Page 25: The San Juan Daily Star Monday, Mar
Page 31 and 32: Monday, March 21, 2016 Official Reg
Page 33 and 34: The San Juan Daily Star the South e
Page 35 and 36: The San Juan Daily Star NA: Solar m
Page 37 and 38: The San Juan Daily Star Colecturía
Page 39 and 40: The San Juan Daily Star RICO INVEST

Star

Create successful ePaper yourself

Delete template?

Save as template?