Health & Science
Is ‘Ida’ a missing link?; Hubble, reborn; Filtered cigarettes aren’t safer; Tumors are doubly depressing; The first period as a harbinger
Is ‘Ida’ a missing link?
An almost perfectly preserved fossil of a 47-million-year-old lemur-like creature may be a “missing link” in the evolution of lower primates into humans, paleontologists say. The fossil—nicknamed “Ida”—is so well preserved that the outline of its fur and flesh remains in the rock, with its last meal of fruit and leaves still visible in its stomach cavity. The paleontologists who bought the fossil from private collectors call Ida “a revolutionary scientific find,” saying that its primate-like features—including grasping hands, with fingernails and opposable thumbs, and human-like ankles and teeth—clearly place it between lemurs and monkeys on the tree of evolution. “This is the first link to all humans, the closest thing we can get to a direct ancestor,” Jorn Hurum of the University of Oslo tells Nationalgeographic.com. Born in what is now Germany, Ida was only 9 months old and the size of a kitten when she apparently drowned in a volcanic lake. Other scientists, while conceding that Hurum has found a remarkably well-preserved type of primitive lemur, challenge Hurum’s classification of Ida as a missing link.
After five days of struggling with a formidable series of mechanical challenges, Atlantis astronauts have come home, having left an entirely rebuilt, more powerful Hubble Space Telescope in orbit, says The Washington Post. In five spacewalks, the astronauts gave Hubble a thorough tuneup, reviving two poorly functioning instruments, installing two new powerful “eyes” on the universe, and replacing the observatory’s gyroscopes, batteries, and computer. Hubble will now have better “vision” than ever, seeing farther into the universe across a wider spectrum of light. “We have a brand-new observatory with full capability that will be more productive than ever in its lifetime,” said Jon Morse, head of astrophysics for NASA. To overhaul Hubble, the astronauts had to overcome obstacles familiar to any home repairman: ill-fitting boots, a power tool that lost power, replacement parts that didn’t fit, and frozen bolts that reminded astronaut Mike Massimino of his Long Island, N.Y., childhood, when his Uncle Frank would curse and struggle with uncooperative parts while doing repairs on his car. “I didn’t use his language,” Massimino said, “but that was pretty close to what was going on with me.”
Filtered cigarettes aren’t safer
“Light” cigarettes may actually be more dangerous than your grandfather’s Marlboros, says a new study. When scientists began documenting the carcinogenic effect of cigarette smoke, in the 1960s, tobacco companies began producing filtered cigarettes with lower tar. But since that time, University of California researchers found, a particular type of lung cancer called adenocarcinoma, has been far more prevalent. Adenocarcinoma develops deep in the microscopic air sacs of lung tissue. Researchers believe this once-rare type of cancer is more common today because smokers have to inhale more strongly on filtered cigarettes to get their nicotine jolt, sucking cancer-causing chemicals deeper into the lungs. “The most likely explanation for it is a change in the cigarette,” study author Dr. David Burns tells the Associated Press.
Tumors are doubly depressing
A diagnosis of cancer is obviously a good reason to be depressed. But new research finds that the feeling isn’t just psychological: Tumors produce high levels of a chemical that can effect mood and make people feel down. Behavioral neuroscientists at the University of Chicago compared depression and anxiety rates in groups of rats with and without tumors. Since rats have no awareness that they have cancer, Dr. Brian Prendergast tells BBCnews.com, “their behavioral changes were likely the result of purely biological factors.” He found that rats with cancer exhibited signs of depression and anxiety, floating passively when placed in water while cancer-free rats swam for safety. The tumor-ridden rats also hoarded and buried objects they were given, and lost interest in eating sweets. The scientists believe that the anxious and depressive behavior is connected to levels of chemicals called cytokines, which are produced by tumors and also by the immune system when it’s battling cancer. Rats with tumors had double the normal level of cytokines, which have a direct, depressing effect on emotional centers in the brain.
The first period as a harbinger
A girl’s first period is a watershed moment in her life, a dividing line between childhood and womanhood. The age at which that first period comes, says a new study, provides a glimpse into her future health and body type. After studying 17,500 women across eight different cultures, researchers at Harvard University and the Massachusetts Institute of Technology identified the genes that determine when a girl will experience the onset of menstruation. These genes, they found, also are connected to body shape and development. Girls who get their periods earlier, at the age of 9 or 10, are more likely to develop a shorter and pudgier physique, and to have a high body mass index in adulthood. Girls who do not begin menstruating until their teens are more likely to be tall and thin, and to have lower risks for cancers of the breast and endometrium. The earlier a woman menstruates, the longer her body is bathed in higher levels of the female sex hormone estrogen, which has been linked to these diseases.