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Tag Archives: science
Aztecs devised sophisticated arithmetic system
By Will DunhamThu
Using written symbols such as hearts, arrows and hands, the ancient Aztecs maintained an arithmetic system that was far more complex than previously understood, scientists said on Thursday.
The Aztecs, an empire in central Mexico toppled by Spanish invaders in 1519, has long been recognized for its sophistication in architecture, engineering, astronomy and other fields. And the new research confirms arithmetic can be added to the list.
The researchers examined hundreds of drawings in two manuscripts dating back to between 1540 and 1544 that were used to document agricultural properties by the Aztec people in the city-state of Tepetlaoztoc, near modern Mexico City.
The Aztecs used a system that included symbols of hearts, hands, arrows, bones, arms as alternatives to using fractions. An examination of these hieroglyphic records showed that the Aztecs used their own calculation system to figure out, for example, the area of a parcel of land.
“What we thought we knew about the Aztec measuring system was a little simplistic. We’ve determined that it was more complex,” researcher Barbara Williams of the University of Wisconsin-Rock County said in a telephone interview.
Williams teamed with Maria del Carmen Jorge y Jorge of the Universidad Nacional Autonoma de Mexico in the study published in the journal Science.
“They used the four mathematical operations of addition, subtraction, multiplication and division. But in almost all of the early societies, they could do everything they needed to do, with just those four. They didn’t need square roots. They didn’t need trigonometry,” Williams said.
The two manuscripts — one found in a library in France and the other in Mexico — were written on European paper by Aztecs a couple of decades after the conquest, using the Aztec system.
They were land records drawn up that helped determine taxation imposed on the local people by the Spaniards, Williams said.
The fact that the Aztecs mathematically calculated areas has been known since 1980, but until now there was little understanding as to how they did it, Williams said.
The Aztec empire held sway over a large part of Mesoamerica for about a century until the arrival of the Spanish, and their capital Tenochtitlan — with towering pyramids and sumptuous architecture — was larger than any European city of the era.
They were a war-like people that many people now associate more with human sacrifice — which they certainly performed — than their many accomplishments. The new research adds further detail to the achievements of the Aztecs in other areas.
“This increases our understanding of Aztec culture. It gets to the idea that it was a numerate society in the rural areas as well as the urban areas — among the surveyors as well as the priests and the royalty,” Williams said.
(Editing by Maggie Fox and Sandra Maler)
ScienceDaily (2008-03-17) — Implantable cardiac defibrillators that are equipped with wireless technology are vulnerable to having private medical information extracted — and even having the devices reprogrammed — without the patients’ knowledge. Not only does this pose a potential security risk, it could also endanger patients’ physical safety. … > read full article
The mysterious G spot – supposedly a route to female sexual satisfaction – can be located with ultrasound, claim Italian scientists. Some women say stimulating a certain part of the vagina triggers powerful orgasms, but medics have not been able to pin down the exact location.
Researchers told New Scientist magazine they found an area of thicker tissue among the women reporting orgasms.
But specialists warned there could be other reasons for this difference.
The existence of the G spot has remained controversial since the 1980s, when the term was coined as a way to explain why some women were able to achieve orgasm through vaginal stimulation, while others were not.Some specialists claim that the term has led to over-anxiety among women who cannot reach satisfaction this way, and their partners.
The latest research, published in the Journal of Sexual Medicine, was carried out the Dr Emmanuele Jannini at the University of L’Aquila, and involved just 20 women.
Ultrasound was used to measure the size and shape of the tissue beyond the “front” wall of the vagina, often suggested as the location of the G spot.
In the nine women who reported being able to achieve vaginal orgasm, the tissues between the vagina and the urethra – which carries urine out of the body – were on average thicker than in the 11 women who could not reach orgasm this way.
|It’s telling people that there is a single, best way to have sex, which isn’t the right thing to do
Dr Petra Boynton
University College London
Dr Jannini said: “For the first time, it is possible to determine by a simple, rapid and inexpensive method if a woman has got a G spot or not.”However, Dr Tim Spector, from St Thomas’ Hospital in London, told New Scientist that the thicker tissue might actually be part of the clitoris – another extremely sensitive area.Another suggestion was that, rather than being the cause of more orgasms, having these frequently might actually lead to better-developed musculature in this area.
Dr Petra Boynton, a sexual psychologist at University College London, said that an entire industry had grown up around the idea of a G spot, and it was unhelpful to label women unable to find theirs as “dysfunctional”.
She said: “We’re all different. Some women will have certain area within the vagina which will be very sensitive, and some won’t – but they won’t necessarily be in the area called the G spot.
“If a woman spends all her time worrying about whether she is normal, or has a G spot or not, she will focus on just one area, and ignore everything else.
“It’s telling people that there is a single, best way to have sex, which isn’t the right thing to do.”
This article should cause all who read it to reconsider the amount of time they use on their cell phone. This article was published on the Scientific American Website.
By Amy Norton
NEW YORK (Reuters Health) – Spending hours on a cell phone each day may affect the quality of a man’s sperm, preliminary research suggests.
In a study of 361 men seen at their infertility clinic, researchers at the Cleveland Clinic found an association between the patients’ cell phone use and their sperm quality.
On average, the more hours the men spent on their cell phones each day, the lower their sperm count and the greater their percentage of abnormal sperm.
The findings, published in the journal Fertility and Sterility, add to questions about the potential health effects of cell phones and other wireless devices. Some studies, for example, have linked long-term cell phone use to a higher risk of brain tumors, though many other studies have found no such connection.
The concern is that, over time, the electromagnetic energy emitted from mobile phones could theoretically harm body tissue — by damaging DNA, for example.
However, the new findings do not prove that cell phones somehow damage sperm, according to the researchers.
“Our results show a strong association of cell phone use with decreased semen quality. However, they do not prove a cause-and- effect relationship,” lead researcher Dr. Ashok Agarwal told Reuters Health.
He and his colleagues based their findings on semen samples from 361 men who came to their infertility clinic over one year. All of the men were questioned about their cell phone habits.
In general, the researchers found, sperm count and sperm quality tended to decline as daily cell phone hours increased. Men who said they used their phones for more than four hours each day had the lowest average sperm count and the fewest normal, viable sperm.
“We infer from our results that heavy cell phone use … is associated with a lower semen quality,” Agarwal said. But whether cell phones somehow directly affect men’s fertility is not clear.
Agarwal said he and his colleagues have two studies underway aiming to shed light on the issue. In one, they are exposing semen samples to electromagnetic radiation from cell phones to see what, if any, effects occur.
The second is a follow-up to the current study that is assessing a larger group of men. Agarwal said this study is more rigorously designed and will account for certain other factors like lifestyle habits and occupational exposures that might affect sperm quality.
SOURCE: Fertility and Sterility, January 2008.