Chinese lunar calendar method of predicting a baby’s sex not accurate
If you’re among the parents-to-be who’ve used one of the increasingly popular online Chinese calendar charts to predict your baby’s sex, a U-M epidemiologist recommends that you hold off on painting the nursery pink or blue.
Dr. Eduardo Villamor of the School of Public Health and colleagues in Sweden and Boston found that the so-called Chinese lunar calendar method of predicting a baby’s sex is no more accurate than flipping a coin.
“We didn’t undertake this study with the goal of being myth-busters. We were just curious about it, really,” Villamor says. “But based on our results, I would not trust these predictions whatsoever.”
Villamor and his colleagues reviewed records of 2.8 million Swedish births, between 1973-2006, to test the accuracy of the Chinese lunar calendar method. The technique involves converting the mother’s age and the month of conception to dates on the Chinese lunar calendar, then plugging those dates into a chart that purportedly predicts the baby’s sex.
Some of the Chinese lunar calendar websites claim accuracy rates of up to 93 percent. But when Villamor and his colleagues compared the Swedish birth records to the charts’ predictions, they found that the Chinese charts were correct about 50 percent of the time — the same chance agreement rate you’d get from flipping a fair coin.
“We found that the accuracy of the Chinese lunar calendar method for the prediction of a baby’s sex leaves much to be desired,” the authors wrote in an article published in the May edition of the journal Paediatric and Perinatal Epidemiology.
— Jim Erickson, News Service
Trapping giant Rydberg atoms for faster quantum computers
In an achievement that could help enable fast quantum computers, U-M physicists have built a better Rydberg atom trap. Rydberg atoms are highly excited, nearly ionized giants that can be thousands of times larger than their ground-state counterparts.
As a result of their size, interactions between Rydberg atoms can be roughly a million times stronger than between regular atoms. This is why they could serve as faster quantum circuits, says Georg Raithel, associate chair and professor in the Department of Physics. Quantum computers could solve problems too complicated for conventional computers. Many scientists believe that the future of computation lies in the quantum realm.
A paper on this research is published in the current edition of Physical Review Letters. The work was presented at the American Physical Society’s Division of Atomic, Molecular and Optical Physics meeting in late May.
Raithel’s team trapped the atoms in what’s called an optical lattice — a crate made of interfering laser beams.
“The optical lattice is better than any other Rydberg atom trap for quantum information processing or high-precision spectroscopy,” Raithel says. “Compared with other traps, optical lattices minimize energy level shifts in the atoms, which is important for these applications.”
Raithel and physics doctoral students Kelly Younge and Sarah Anderson started with ground-state atoms of the soft metal rubidium. At room temperature, the atoms whiz around at the speed of sound, about 300 meters per second. The researchers hit them with lasers to cool and slow them to 10 centimeters per second.
The physicists used a technique called “microwave spectroscopy,” to determine how the lattice affected the Rydberg atoms, and in general how the atoms behaved in the trap.
— Nicole Casal Moore, News Service
Study to improve quality of life and outcomes for kids with heart defect
A trial on shunts used to direct blood flow to the lungs, led by researchers at the C.S. Mott Children’s Hospital will lead to better outcomes for kids worldwide born with hypoplastic left heart syndrome, the most common severe heart birth defect.
Under the leadership of U-M, the first multi-institutional randomized prospective trial ever conducted in congenital heart surgery was just completed by the Pediatric Heart Network with funding from the National Heart, Lung, Blood Institute.
Kids with the hypoplastic left heart syndrome have hearts that don’t develop properly in the womb. Because the left side of the heart fails to develop, they are often referred to as being born with half a heart.
This groundbreaking study is published in the May 27 issue of the New England Journal of Medicine. Dr. Richard Ohye, division head of the Pediatric Cardiovascular Surgery at the C.S. Mott Children’s Hospital, is the study chair and lead author.
“Congenital heart disease is much more common than people realize,” Ohye says. “Heart abnormalities are the most common birth defect, and it occurs in almost one out of every 100 live births.”
Twenty years ago, doctors were unable to save these children with hypoplastic left heart syndrome. Today, because of efforts by the U-M Congenital Heart Center and other centers like it around the world, most of these infants can be saved through a series of operations that can be compared to re-plumbing their heart.
The treatment of hypoplastic left heart syndrome requires three operations and the first one is done around the time of birth, the second one at about 4 to 6 months of age and the last one at 18 to 24 months of age.
— Margarita Bauza, UMHS Public Relations
Men are dying for sex: Mating competition explains excess male mortality
Men die at higher rates than women across the lifespan. A new study suggests that this excess mortality is the price of reproductive competition.
Researchers have long known that women outlive men on average, and more recently have discovered that men have higher mortality risks across the entire lifespan. Researcher Daniel Kruger offers this explanation: It is all about sex.
Women invest more physiologically in reproduction than men, thus men compete with other men for mating partners and try to make themselves attractive to women. This competition leads to strategies that are riskier for men both behaviorally and physiologically, and these result in higher levels of mortality.
“If mating competition is responsible for excess male mortality, then the more mating competition there is, the higher excess male mortality will be,” says Kruger, an assistant research professor in the School of Public Health. In the current study, Kruger shows that two factors related to the level of male reproductive competition contribute to higher rates of risk-taking and mortality.
The first factor is polygyny, the social situation in which one man maintains sexual relations with many women (the opposite is polyandry — one women and many men). Several species of primates show high levels of polygyny, where one dominant male mates with most of the females in the group, and other males are left out. Human cultures have varying degrees of polygyny, and Kruger found that the more prevalent the practice, the higher the rate of male mortality.
The second factor: the degree of economic inequality. In mate selection, men are valued for the resource investment that they can provide, bringing benefits to their offspring. The wider the gap between rich and poor, the more likely men are to die young. In less egalitarian societies, a man with what scientists call “resource control” — money, property and economic security — is more likely to find sexual partners.
The study appears in the current issue of the journal Evolutionary Psychology.
— Terri Mellow, School of Public Health
Flu doesn’t die out, it hides out
Every autumn, as predictably as falling leaves, flu season descends upon us. Every spring, just as predictably, the season comes to a close. This cyclical pattern, common in temperate regions, is well known, but the driving forces behind it have been in question.
Do existing strains die off each spring, only to be replaced each fall by new founding strains from other parts of the world, or does a “hidden chain of sickness” persist over the summer, seeding the next season’s epidemic?
A genetic analysis by postdoctoral fellow Trevor Bedford and colleagues at U-M, Howard Hughes Medical Institute and Florida State University reveals that in the United States, not all strains of influenza die off at the end of winter; some move southward to South America, and some migrate even farther. The paper was published online May 27 in the open-access journal PLoS Pathogens.
“The prevailing view that has developed over the past three years or so is the out-of-tropics hypothesis, in which the strains that bring about each temperate flu season originate from China and Southeast Asia, where influenza A is less seasonal,” Bedford says.
He and his colleagues tested that hypothesis by analyzing genetic sequences from influenza A (H3N2) viruses collected from patients around the world between 1998-2009 and constructing a tree showing relationships among the viruses. The resulting mathematical model accounted for evolutionary processes and rates of migration.
In addition, growing knowledge about patterns of flu migration eventually may make it possible to tailor vaccines to particular locations, Bedford says.
An additional U-M author is Mercedes Pascual, the Rosemary Grant Collegiate Professor of Ecology and Evolutionary Biology and a Howard Hughes Medical Institute Investigator.
— Nancy Ross-Flanigan, News Service
