Studies and Analyses

Parasite genes reveal modern and archaic humans made contact

A University of Utah study showing how lice evolved with the people they infested reveals that a now-extinct species of early human came into direct contact with our species about 25,000 years ago and spread the parasites to our ancestors.

The study found modern humans have two genetically distinct types of head lice. One type is found worldwide and evolved on the ancestors of our species, Homo sapiens. The second

A new study from Johns Hopkins suggests that routine widening of the vagina, a procedure known as an episiotomy, does not reduce the risk of injury to infants during a complicated birth, such as when a baby’s shoulders are stuck in the birth canal after the head is already out. Instead, physicians can proceed directly to physical maneuvering of the infant, thereby avoiding unnecessary trauma to the mother and, at the same time, averting injury to the baby. An episiotomy should only be perfor

A new study finds that most malaria deaths among U.S. travelers between 1963 and 2001 were preventable.

The study is published in the Oct. 5, 2004, issue of Annals of Internal Medicine, a peer-reviewed medical journal published in Philadelphia by the American College of Physicians.

Although indigenous transmission of malaria was eradicated from the United States in the late 1940s, every year about 1,500 malaria cases occur in the United States. Most infections occur in peop

Emotionally draining jobs bring few monetary rewards if the employment does not require great intellectual demands, a new University of Florida study finds.

Friendly waiters, angry bill collectors and nurturing child-care workers are among the many American workers who experience emotionally charged encounters that require shows of empathy or other feelings but have little recompense, said John Kammeyer-Mueller, a UF management professor and one of the study’s researchers.

A study by Cornell University researchers finds that when young adults are served larger portions from one week to the next they overeat by almost 40 percent. Eating larger portions over time could account for the growth of the American girth over the past 20 years, the researchers say.

“The more food we served to the college-student volunteers in our eating study, the more they ate,” says David Levitsky, professor of nutritional sciences and of psychology at Cornell. “Since we k

CT-guided radiofrequency ablation (RFA) is effective in easing the symptoms of lung tumors that cannot be removed by surgery, and enhancement pattern and changes in the size of the tumor as shown on CT are the most important factors for determining whether that ablation has been successful, according to a pair of independent studies in the October 2004 issue of the American Journal of Roentgenology.

For the first study, researchers from Caserta’s S. Sebastiano Hospital in Ita