The use of color symbolism by prehistoric man in Africa may have occurred more than 200,000 years ago, according to a British archeologist whose findings were announced at the annual festival for the British Association for the Advancement of Science.
Lawrence Barham, a researcher from Liverpool University, has been studying ancient human artifacts at a cave site known as Twin Rivers in southern Zambia.
A range of mineral pigments, or ochres, have been found at the site, leading Barham to hypothesize that they may have been used ritualistically by early man, in much the same way some cultures today use color to mark passages of childhood into adulthood or of a warrior becoming an elder.
If his theory is correct, it would mean abstract thinking by early humans would have developed far earlier than previously thought.
"As an archaeologist I am interested to find out where color symbolism first appears because for color symbolism to work it must be attached to language," Barham said.
"Color symbolism is an abstraction and we cannot work this abstraction without language; so this is a proxy for trying to find in the archaeological record real echoes for the emergence of language."
Evidence found at the Twin Rivers site suggests tools were becoming more complex, blades attached to handles rather than just simple handaxes. At the same time ochres of a wide range of colors were being used.
Ochres are derived from scraping rocks and mixing the resulting powder with another substance, such as animal fat, to create paint or dye. The ochres found at the Twins Rivers’ site include red, yellow, brown, pink, black and even purple. The type of humans using them is not known, although a bone fragment points to Homo heidelbergensis, a large-brained ancestor of modern man.
Still, skeptics say the ochres could be merely functional, used for such things as preserving hides, or as glue to fasten stone blades to shafts or handles. But Barham disagrees.
"If you were to argue that these oxides were purely functional and have no symbolic value, you have to explain away the range of colors that are being selected from different places in the landscape. Because if it was just for the iron element, any of them would do - the red, or the yellow. Some are closer to the site than others, so it seems that people were deliberately selecting the material for the color property. That's my argument anyway", Barham said.
You're invited to attend the annual Fall Color Blast on Sunday, October 1, from 1-5pm, at the Warner Nature Center. The event is free and features a professional storyteller, live fiddle music, bird banding demonstrations, canoeing, rides on a solar-powered pontoon, hikes, kids' crafts, free apple pie and ice cream, cider and coffee, and more. (Want more information about programs at the Center?)
Since the migrating birds avoid crossing large expanses of water, Lake Superior acts as a funnel, forcing them into Duluth where the lake narrows to its western point, and crossing is easier. This means that thousands of hawks and raptors fly over the region, coming down from Canada and other points north. One of the best sites to see them is at Hawk Ridge Nature Reserve, which is situated, in eastern Duluth at an overlook along the city’s Skyline Parkway.
The observation site draws not only vast numbers of birds (averaging over 94,000 per year) but also vast numbers of visitors who come each fall to watch the migration and enjoy the stunning panoramic views of Lake Superior and eastern Duluth.
If conditions are right, a lucky visitor may see Broad-wing Hawks, Osprey, Bald and Golden Eagles, Red-tailed and Rough-legged Hawks, American Kestrels, Northern Goshawks, and Peregrine Falcons. Great Horned and Long-eared Owls can also be seen at times.
The raptors can be seen just about everyday during Autumn, except when it’s raining, Generally, the birds begin migrating over Hawk Ridge in mid-August through November. The best time to spot them is when the wind is blowing in from the west or northwest for a couple of days straight. Official counters scan the skies with binoculars most days and tally the migration. During “The Big Days”, which generally take place between September 10-25, tens of thousands of Broad-winged Hawks can be spotted soaring over the ridge. This past week over 28,000 of them were counted in just two days!
For directions and further information visit the Hawk Ridge Bird Observatory website. Then pack up your binoculars and camera, and head north to Duluth.
The CDC has more than 100 million doses of this year's flu vaccine available--enough so that anyone who wants one can get one. (Doctors and clinics will start receiving the vaccine next month.)
Last year 86 million doses were available, but 4.8 million went unused. Yet 200 million Americans are either considered high risk themselves or have close contact with someone at high risk and should consider getting the shot.
People on the CDC's priority list include:
It's best to get vaccinated in October or November so there's time for immunity to develop before the flu season hits. But numbers of influenza cases usually peak in February, so even a late shot offers some protection.
Every year somewhere between 5 and 20% of the US population catches influenza. 200,000 of them need hospital care, and 36,000 die.
So...will you be getting a flu shot this year? Vote in our poll, and tell us why or why not.
Today the CDC announced its new recommendation that all Americans between the ages of 13 and 64 be routinely checked for HIV, the virus that causes AIDS. Why the change? About one million Americans are infected with HIV, but 25% of them have no idea that they're carrying the virus. Routine testing should help check the spread of the disease and preserve health as infections are caught earlier.
The CDC's recommendation isn't binding, but it does influence what doctors do and what health insurance covers. And the blanket recommendation might help reduce the stigma associated with HIV testing.
What do you think? Will you get screened for HIV at your next physical? Why or why not?
This article, by Tyler Rushmeyer, appeared in the local news section of today's Pioneer Press:
Racket bugging residents: Night music made by katydid colony
Many White Bear Lake residents were baffled when they started hearing a new sound reverberating through their neighborhoods.
As night falls, a loud "yack, yack" sound has filled the air. "It sounds like a tropical rainforest on my block," said White Bear Lake resident Mark Nevala, one of several people to call city officials asking about the noise.
The culprit: katydids, loud insects performing mating calls by rubbing their wings together. The mating season should last into early October.
Closely related to grasshoppers and crickets, katydids are spread throughout Minnesota. The bugs residents are hearing are the northern katydid species, said Dick Oehlenschlager, assistant curator and collections manager for biology at the Science Museum of Minnesota.
"They move in colonies and shift every year, and this year their colony seems to have taken residence in the Twin Cities area," he said.
The insects--about 2 inches long and bright green, with long, coiled antennae--are near-motionless during the day and reside on the leaves of trees. But soon after dusk, they become active. They are difficult to spot, Oehlenschlager said, which is why many people are confused about where the noise is coming from.
"Even I didn't know what I was hearing the first couple times I came in contact with them," Oehlenschlager said.
Look for our new fall phenology section, featuring other seasonal behaviors of insects and birds, coming to the Mississippi River Gallery and the Buzz website after next week.
A new paper published in the Procedings of the National Academy of Sciences suggests that, as parents preferentially select boys over girls and gender imbalances grow, we'll see rising levels of anti-social and violent behavior.
"There are already an estimated 80 million missing females in India and China alone."
(According to the World Bank, in 2004 48.6% of China's population and 48.7% of India's population were female. By contrast, females made up 49.1% of the total population in East Asia, and 52.1% in all of Europe and Central Asia.)
The Reuters news report says,
"'This trend would lead to increased levels of anti-social behavior and violence, as gender is a well-established correlate of crime, and especially violent crime,' [the authors] said, adding the trend would threaten stability and security in many societies."
The authors of the paper call for "measures to reduce sex-selection and an urgent change in cultural attitudes." But that seems easier said than done.
Do you think it's possible to change cultural attitudes about gender preference? It's easy to say this is a problem of East Asian cultures, but what about the US? Do we have cultural preferences about our children's genders, too?
A type of grass created by bioengineers in a lab has escaped out into the environment for the first time--at least that we've noticed.
The grass is being developed to resist the common herbicide Roundup. Scotts Miracle-Gro Company and Monsanto, who are engineering this grass, hope to use it on golf courses so that Roundup could be sprayed to kill weeds without killing the grass.
Well, I've been doing lots of research into nanotechnology and the social concerns around its use. Just like bioengineered crops, people worry that we don't have a clue what could happen if these plants or particles, in the case of nanotechnology, escape into the environment.
Could the genes from this Roundup resistant grass find their way into wild grasses? If they do it might be that much harder to eliminate weeds that grow wild in our environment.
Well, this story got me and some of my coworkers thinking about the definitions of genetic engineering and nanotech. In genetics we are manipulating DNA at the nanoscale. In nanotechnology we are manipulating molecules and atoms at the nanoscale. Despite having many people tell me that they are unique I still don't totally get it.
I think it mostly lies in the methods with which the different sciences go about manipulating things. The processes that genetic engineers use to create a new kind of grass are unique from those that nanotech scientists use to engineer something like carbon nanotubes.
So what do you think? I will ask around and see if I can get some answers to the question, "Is genetic engineering a type of nanotechnology?"
The question regarding whether dinosaurs were warm-blooded or cold-blooded has been debated for decades. Currently, most scientists believe that dinosaurs were warm-blooded and used internal mechanisms to maintain a constant body temperature. However, what that internal body temperature was could have fluctuated depending on the size of the dinosaur, making it possible for dinosaurs to have been both.
The bigger the hotter
Researchers at the University of Florida devised a mathematical formula that describes the connection between temperature, growth rate and biomass across a wide range of modern creatures. They then applied this formula to newly available fossil data on the growth rates of eight dinosaur species.
The equation showed that the bigger a dinosaur was the hotter is was. Smaller dinosaurs had internal body temperatures of around 77º Fahrenheit, which was close to the average air temperature of their time, so could have regulated their body temperatures much like modern cold-blooded reptiles. As dinosaurs grew larger, and the ratio of their surface area to volume fell, they became less efficient as dissipating their own metabolic heat. Because of this increased internal body temperature, dinosaurs probably had to develop behavioral or other adaptations to avoid overheating.
Body temperature influenced dinosaur size
One of the larger dinosaurs studied, Sauroposeidon proteles, weighed nearly 120,000 pounds. Applying the mathematical formula reveals that it may have had a body temperature close to 118º Fahrenheit, which is about as hot as most living creatures can get before the proteins in their bodies begin to break down. Because of this, the size of the largest dinosaurs may have been limited by their internal body temperatures.