Rick Crammond demonstrates how effective shielding is using a fun demonstration. Have you ever stripped some shielded cable and found the foil wrapped around the wires or looked in some electronic gear and seen some some copper paint on the inside of the cover and wondered how effective it is? Well this demonstration shows you that a bit of thin metal can really do some amazing shielding.
“Just a pat on the back or a reassuring touch on the arm can be a powerful tool to influence behavior, according to new research. And it could determine whether someone invests in a risky financial venture or decides to play it safe. “It’s a very effective way of suddenly influencing people’s behavior without them realizing they are being influenced,” said Jonathan Levav, a professor of business and marketing at Columbia University in New York. “If you’re a doctor, or are in sales, this is a form of communication you might want to keep in mind,” he added in an interview.
Levav ’s findings, which are reported in the journal Psychological Science, are based on a series of experiments involving touch. In one study 67 men and women were asked to choose between a cash payoff and a risky gamble and then touched on the shoulder and back by male and female researchers. Levav and his co-author Jennifer Argo, of the University of Alberta in Canada, found that both sexes were more likely to select gambles with no guarantees of a payoff if they had been made to feel more comfortable, especially if touched by a woman.
In another experiment, 105 people were asked to allocate their money between two investments — a bond that delivered a four percent yearly return or a risky deal with no guaranteed return. Again, people who were lightly touched on the shoulder by a woman were more likely to select the option with the most risk. Levav and Argo suggested that the connection between comfort and risk goes back to our earliest recollections of human bonding. “A simple pat on the back of the shoulder by a female in a way that connotes support may evoke feelings that are similar to the sense of security afforded by a mother’s comforting touch in infancy,” they wrote in the study.”
“Mr. Osborne, may I be excused? My brain is full,” a student with a particularly tiny head asks his classroom teacher in a classic Far Side comic by Gary Larson. The deadpan answer to this question would be, “No, your brain is almost certainly not full.” Although there must be a physical limit to how many memories we can store, it is extremely large. We don’t have to worry about running out of space in our lifetime.
The human brain consists of about one billion neurons. Each neuron forms about 1,000 connections to other neurons, amounting to more than a trillion connections. If each neuron could only help store a single memory, running out of space would be a problem. You might have only a few gigabytes of storage space, similar to the space in an iPod or a USB flash drive. Yet neurons combine so that each one helps with many memories at a time, exponentially increasing the brain’s memory storage capacity to something closer to around 2.5 petabytes (or a million gigabytes). For comparison, if your brain worked like a digital video recorder in a television, 2.5 petabytes would be enough to hold three million hours of TV shows. You would have to leave the TV running continuously for more than 300 years to use up all that storage.
The brain’s exact storage capacity for memories is difficult to calculate. First, we do not know how to measure the size of a memory. Second, certain memories involve more details and thus take up more space; other memories are forgotten and thus free up space. Additionally, some information is just not worth remembering in the first place.
This is good news because our brain can keep up as we seek new experiences over our lifetime. If the human life span were significantly extended, could we fill our brains? I’m not sure. Ask me again in 100 years.
The connection between gut bacteria and obesity has gained some weight, with new findings demonstrating links in mice among immune-system malfunction, bacterial imbalance and increased appetite.
Mice with altered immune systems developed metabolic disorders and were prone to overeating. When microbes from their stomachs were transplanted into other mice, they also become obese.
“This supports the notion that some of the increase in obesity may be because of changes to gut bacteria,” said Andrew Gewirtz, an Emory University immunologist and co-author of the study, published March 4 in Science.
The findings are the latest in a growing body of research about the long-unappreciated role of bacteria in our bodies. Bacterial cells actually outnumber human cells in the body: From an outside perspective, people are not so much individual organisms as symbiotic human-bacteria collectives.
Disturbances to internal bacteria have been linked to asthma, cancer and many autoimmune diseases. Gut flora have also been linked to obesity. In 2006, researchers led by Washington University microbiologist Jeffrey Gordon documented bacterial changes in the stomachs of mice who became obese on high-fat diets.
When transplanted, their gut bugs turned other mice obese, suggesting that altered bacteria were not only an effect of weight gain, but a cause. The Science findings complement those, but also emphasize the immune system’s role and the possibility of appetite change.
“The reason why people are eating too much may not simply be because unhealthy food is cheap and available, but that their appetites may be driven by changes in gut bacteria,” said Gewirtz,
In the Science study, Gewirtz and Emery microbiologist Matam Vijay-Kumar studied a strain of mice deficient in TLR-5, a gene that’s required for immune systems to recognize many types of bacteria.
They found that TLR-5–deficient mice are about 20 percent heavier than regular mice. They overeat, have high blood pressure and high cholesterol, and are insulin-resistant. In humans, that constellation of conditions is known as metabolic syndrome, and in both people and mice leads to obesity and diabetes.
Earlier research had found unusual patterns of bacteria in the guts of those mice. When the researchers transferred bacteria from the stomachs of TLR-5–deficient mice to mice without gut bacteria, the recipients started to eat more, and soon developed metabolic syndrome.
“It’s a really exciting paper. It confirms and supports a lot of the findings we’ve had, and adds in the interaction between gut bacteria and the immune system,” said Peter Turnbaugh, a systems biologist who moved from Jeffrey Gordon’s lab to Harvard University. “It’s been thought for a long time that maybe the immune system is an important regulator of what’s in the gut.”
How gut bacteria produce metabolic changes isn’t known. They may process nutrients directly, or alter the activity of metabolism-regulating genes.
Mice used in the research are not considered exact models of bacteria and obesity in humans. Instead they’re models of these sorts of relationships likely to exist in people. Gewirtz’s team is now investigating whether people with metabolic syndrome have unusual gut bacteria.
The findings don’t suggest obesity is literally contagious, said Turnbaugh. But they do raise the possibility of altering the composition of gut bacteria, either directly or — more realistically — by learning what sort of environmental and lifestyle factors produce obesity-causing bugs.
One possible culprit is the ubiquitous presence of antibiotics, both prescribed and in the environment, said Gewirtz.
“It may be that an unintended consequence of this has been the upset of bacterial populations that are promoting obesity and metabolic syndrome,” he said.
Image: Left, regular and TLR-5–knockout mice. Right, a comparison of their insulin-producing islet cells./Andrew Gewirtz
Female short-nosed fruit bats in China’s Guangdong Province show their preference for certain males by fellating them, according to an October journal article. Researchers observed that licked males were able to copulate longer, thus improving the likelihood of insemination. (The scientists also confirmed that bats mate while upside down.)
[Chronicle of Higher Education, 10-29-09]