Home History Department History is the study of the vast record of human experience, the collective memory of humankind. As memory defines selfhood and guides behavior, so history teaches about social identity and responsibility. Just as memory changes and matures, so does the collective understanding of the past change as new evidence is discovered and new perspectives are developed. Like a detective hunt, the discipline of history teaches us to seek facts, weigh interpretations, and draw conclusions.
Virginia Hughes February 7, Some 40 years ago, researchers at the University of Missouri were searching for an alternative to the condom — a cheap, trustworthy and reversible form of male birth control. For their first studypublished inthey strapped anesthetized rats, face-down, to a plexiglass platform with a cut-out cup full of water for their dangling scrota.
Heat, for example, can kill sperm which is thought to explain why the testes hang outside of the body.
So some of the animals got a degree Fahrenheit water bath for 15 minutes. Others received a dose of infrared radiation, or short blasts of microwaves or ultrasound. After treatment, the animals had constant access to females until they impregnated them.
Infrared radiation doubled that sterile window, to 75 days. The best protocol, by far, was ultrasound, which the researchers transmitted through the water cup. One 5-minute exposure to these high-frequency sound waves led to seven months of sterility.
Histology studies of the tissue confirmed that the animals showed a big loss of developing sperm at two months post-ultrasound, but were back to normal by 10 months. Developing sperm in the rat testis Over the next two years, the scientists, led by Mostofa Fahim, observed the sperm-killing and painless, by the way effects of ultrasound in cats, dogs, monkeys and men.
The work was forgotten for decades. Fahim died inand most of the equipment he used is no longer sold. No one knows exactly why ultrasound causes sterility.
It probably has to do with the heat produced when tissue absorbs the high-pressure sound waves. But something else is going on, too: Fahim hypothesized that the ultrasound affected the ion exchange in fluid of different areas of the testes, leading to conditions that prevented sperm development.Virginia Hughes is now the science editor over there, and people like Dan Vergano and Peter Aldous have been writing for them.
These are excellent science writers. Jul 11, · Author information: (1)1] Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia , USA  Allen Institute for Brain Science, North 34th Street, Suite , Seattle, Washington , USA.
By Virginia Hughes.
I called Matt Shipman, a science writer and press information officer at North Carolina State University, to ask what he thought of the findings.
Shipman has been a press. David Quammen is a well-known science writer and explorer. Author of four books of fiction and eight non-fiction titles including Spillover: Animal Infections and the next Human Pandemic.
He is a frequent contributor to National Geographic Magazine among other periodical publications. by Virginia Hughes / 17 November Believing that you’re involved in a live interaction, even when you’re not, is enough to activate the social brain, according to unpublished work presented today at the Society for Neuroscience annual meeting in Washington, D.C.
Roberta Kwok is a freelance science writer based near Seattle, Washington. Her work has appeared in Nature, srmvision.com, Science News, Audubon, and U.S. N ews & .