Evidence of Dinosaur Parenting
Dinosaurs are not generally noted for their parenting skills, but a recent discovery suggests that nurturing did occur among them and that adults cared for their young.
The finding, from Liaoning in China, involves an adult Psittacosaurus surrounded by 34 young ones, which are described in the current edition of the journal Nature as "closely associated" with the adult. The small dinosaurs' fossils were all clustered in an area little more than five square feet.
The young were all of a similar size, and many were in lifelike postures. The animals died together at the same time, the apparent victims of volcanic debris, flooding or the collapse of an underground burrow, the researchers concluded.
Crocodiles and birds provide significant care to their young -- helping them to hatch, feeding them and protecting them from predators -- and scientists have long speculated about whether their distant dinosaur ancestors did, as well. The report says that the collection of Psittacosaurus young with an adult "is consistent with a biological relationship and post-hatching parental care."
The journal article, by researchers at the Dalian Natural History Museum in China and David Varricchio of Montana State University in Bozeman, says that the animals were not recent hatchlings -- a finding based on the size of the juveniles compared with the adult and on the extent of bone development in the young.
That led to the conclusion that the young had been living with the adult for some time, and that something akin to parenting was going on.
-- Marc Kaufman
Optimism and the Elderly
A positive and optimistic attitude can protect elderly people from becoming frail, according to new research exploring the power of positive thinking.
Positive attitudes have been known to speed up the healing of fractures, slow the progression of HIV infection, and protect against heart disease and stroke. The new study adds to a growing literature on the virtues of being optimistic, having self-esteem, being happy and enjoying life.
The seven-year study sampled a large number of elderly Mexican Americans in the Southwest. Frailty was measured using criteria such as weight loss, exhaustion, walking speed and grip strength. People with the most positive attitudes at the start of the study had the smallest declines as time went on, according to University of Texas researchers Glenn V. Ostir, Kenneth J. Ottenbacher and Kyriakos S. Markides.
Long the mainstay of self-help books, the psychological study of positive emotions is slowly becoming a growth industry. In an article published this month in the journal Psychology and Aging, researchers said the new data could help the nation's growing elderly population stave off physical ailments.
The researchers noted that positive attitudes might even compensate for the ill effects of poverty and may reverse the effects of stress and negative emotions on cardiovascular disease. Building and maintaining relationships with others, the authors noted, "is associated with better mental health, less disease and disability, and increased survival."
-- Shankar Vedantam
Hope for Delayed Childbearing
Women whose ovaries must be removed early because of disease or who want to delay childbearing until menopause have few fertility options today. Men can freeze their sperm for use years later. But eggs do not freeze well -- or more specifically, do not thaw well -- unless they have already been fertilized. That means women hoping to delay childbearing must decide in advance who the father will be -- a decision that many women in that situation want to delay, as well.
Now a report from Italy offers new hope for women who want to put their fecundity on ice.
Italy is fertile ground for such research because, by law, women undergoing in vitro fertilization can create no more than three embryos at a time, and all three must be transferred immediately to the womb. That means any additional eggs retrieved for the procedure would be wasted unless they could be saved for later.
Andrea Borini of the University of Bologna froze eggs retrieved from 68 women -- 51 undergoing immediate IVF and also wishing to save their extra eggs for future attempts, and 17 who wanted to preserve their childbearing options but who had no partner to provide sperm. A total of 737 eggs were thawed after varying periods of time, of which 37 percent survived. Of those, 45 percent were successfully fertilized, and 104 of the healthiest embryos were transferred to the women's wombs. While most did not result in pregnancies and three miscarriages occurred for unknown reasons, 13 babies were born, the team reports in the September issue of the journal Fertility and Sterility.
Those births are among the first few dozen from frozen eggs reported in recent years. Scientists said more research will be needed to improve those efficiencies and to show definitively that the procedure does not cause genetic abnormalities in offspring.
-- Rick Weiss