Posted 3 months ago

neurosciencestuff:

Sleep is the Price the Brain Pays for Learning

Why do animals ranging from fruit flies to humans all need to sleep? After all, sleep disconnects them from their environment, puts them at risk and keeps them from seeking food or mates for large parts of the day.

Two leading sleep scientists from the University of Wisconsin School of Medicine and Public Health say that their synaptic homeostasis hypothesis of sleep or “SHY” challenges the theory that sleep strengthens brain connections.

The SHY hypothesis, which takes into account years of evidence from human and animal studies, says that sleep is important because it weakens the connections among brain cells to save energy, avoid cellular stress, and maintain the ability of neurons to respond selectively to stimuli.

“Sleep is the price the brain must pay for learning and memory,” says Dr. Giulio Tononi, of the UW Center for Sleep and Consciousness. “During wake, learning strengthens the synaptic connections throughout the brain, increasing the need for energy and saturating the brain with new information. Sleep allows the brain to reset, helping integrate newly learned material with consolidated memories, so the brain can begin anew the next day.”

Tononi and his co-author Dr. Chiara Cirelli, both professors of psychiatry, explain their hypothesis in a review article in today’s issue of the journal Neuron. Their laboratory studies sleep and consciousness in animals ranging from fruit flies to humans; SHY takes into account evidence from molecular, electrophysiological and behavioral studies, as well as from computer simulations.”Synaptic homeostasis” refers to the brain’s ability to maintain a balance in the strength of connections within its nerve cells.

Why would the brain need to reset? Suppose someone spent the waking hours learning a new skill, such as riding a bike. The circuits involved in learning would be greatly strengthened, but the next day the brain will need to pay attention to learning a new task. Thus, those bike- riding circuits would need to be damped down so they don’t interfere with the new day’s learning.

“Sleep helps the brain renormalize synaptic strength based on a comprehensive sampling of its overall knowledge of the environment,” Tononi says, “rather than being biased by the particular inputs of a particular waking day.” 

The reason we don’t also forget how to ride a bike after a night’s sleep is because those active circuits are damped down less than those that weren’t actively involved in learning. Indeed, there is evidence that sleep enhances important features of memory, including acquisition, consolidation, gist extraction, integration and “smart forgetting,” which allows the brain to rid itself of the inevitable accumulation of unimportant details.

However, one common belief is that sleep helps memory by further strengthening the neural circuits during learning while awake. But Tononi and Cirelli believe that consolidation and integration of memories, as well as the restoration of the ability to learn, all come from the ability of sleep to decrease synaptic strength and enhance signal-to-noise ratios.

While the review finds testable evidence for the SHY hypothesis, it also points to open issues. One question is whether the brain could achieve synaptic homeostasis during wake, by having only some circuits engaged, and the rest off-line and thus resetting themselves.

Other areas for future research include the specific function of REM sleep (when most dreaming occurs) and the possibly crucial role of sleep during development, a time of intense learning and massive remodeling of brain.

Posted 4 months ago

Dining customs from around the world

bonappetour:

Traveling to a new country this holiday season? Bet what’s on the itinerary - food, food and more FOOD! But hold on, guys! Did you know about the various dining customs in different parts of the world (that’s right, there are actually rules to stuffing your faces!) While travelling, it is not just the new foods but also the ways of eating that gives us new perspectives to bring home! Check out these unique customs, avoid embarrassing yourself and eat like a pro wherever you go! 

In UK

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Tilt the bowl away from you, and scoop the soup the soup away from you before sipping it from the side of the soup. This is supposed to a classy way of drinking soup. Dine with our host, Sneha in london, and let her share with you more unique customs from UK! 

In an Indian household

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Normally, when you clear your plate, it is taken away. In India or Thailand, for example, if you clear your plate, it means that you are still hungry, so it is customary to leave a small morsel of food on the plate.  Going to Singapore? Dine with BonAppetour host, Santha, and learn more about Indian customs from her! 

In Germany

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On the other end, in Germany, one never eats with his hands. A fork and knife is always used. Also, do not insult your host by using a knife to cut the boiled potates, use the side of a fork instead. Using a knife would mean that the boiled potatoes are not tender and well-cooked enough! Join our host Tanja in Germany for a delicious meal and put this into practice! 

In Southeast Asian and Middle Eastern households

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Traditional families prefer to eat food with their hands rather that using cutlery. Also, only the right hand must be used to eat, not the left. The left land is considered unclean, as it is used to clean yourself after excretion… Let our host, Nadya, show you a glimpse of southeast asian hospitality. Reserve a meal with her! 

In a Chinese household 

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Never stick the chopsticks into the rice bowl, as this symbolizes the incense sticks used in funerals! Always lay it flat on the top of the rice bowl. Join a true-blue Chinese family for a delicious home-made meal! 

In Japan

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Feel free to slurp your noodles or burp after a meal in Japan, as this shows a sense of satisfaction that the meal was indeed delicious. 

And finally

When in Rome…

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…Do as the Roman do, and eat your meals at a leisurely pace. You are expected to enjoy every bite, and not rush through the meal. Meals are often broken into a few distinct courses, with bread and olive oil available on the table throughout. 

It’s not such a small world, after all.

Posted 4 months ago
Science, my lad, is made up of mistakes, but they are mistakes which it is useful to make, because they lead little by little to the truth.
Jules Verne, A Journey to the Center of the Earth (via utcjonesobservatory)
Posted 5 months ago
Posted 5 months ago

astrodidact:

The Magnificent Tail of Comet McNaught 

Explanation: Comet McNaught, the Great Comet of 2007, grew a spectacularly long and filamentary tail. The magnificent tail spread across the sky and was visible for several days to Southern Hemisphere observers just after sunset. The amazing tail showed its greatest extent on long-duration, wide-angle camera exposures. During some times, just the tail itself estimated to attain a peak brightness of magnitude-5 (minus five), was caught by the comet’s discoverer in the above image just after sunset in January 2007 from Siding Spring Observatory in Australia. Comet McNaught, the brightest comet in decades, thenfaded as it moved further into southern skies and away from the Sun and Earth. Within the next two weeks of 2013, rapidly brightening Comet ISON might sprout a tail that rivals even Comet McNaught.

Image Credit & Copyright: Robert H. McNaught

Posted 5 months ago
Posted 5 months ago

Asteroids could be used as transport to deep space

spaceexp:

Asteroids could be used as natural spaceships for travels to the deep space, a Russian space industry scientist said Thursday. “There are about 10,000 asteroids orbiting close to the Earth and about 2 millions of them in total,” head of the Designer and Research Bureau in the Khrunichev Research and Production Space Center, Sergei Antonenko, told the Technoprom-2013 conference in Novosibirsk, southern Siberia.

Full article

Posted 5 months ago

thenewenlightenmentage:

How Mars Looked 4 Billion Years Ago

Filled with idyllic lakes and clouds! 

What would a habitable, watery Mars look like? Four billion years ago, the dry, dusty planet may have had enough of an atmosphere to support bodies of water. Perhaps it looked like this beautiful, cloud-covered lake scene that animators at NASA’s Conceptual Image Lab imagine in their latest video.

The animation, which NASA says is one of the most complex it has ever produced, was created with the help of the scientists working on the Mars Atmosphere and Volatile Evolution (MAVEN) mission, which launches Nov. 18 from Cape Canaveral. MAVEN will study how the climate on Mars has changed over time by looking at the gases in its upper atmosphere.

Take a look. Go soaring across the ancient Martian landscape accompanied by what sounds like the soundtrack to an epic fantasy movie, flying over lakes (which may have existed on a young, thick-atmosphered Mars) and mountainous canyons, and watch as it slowly transforms into the red, rocky planet we’ve come to know today.

[NASA]

Related: What Happened to Mars? A Planetary Mystery [Phys.org]

Posted 5 months ago
[My biggest mistake is probably] weighing too much on someone’s talent and not someone’s personality. I think it matters whether someone has a good heart.
One of 16 quotes from a recent Business Insider article, 16 Genius Quotes From Eccentric Billionaire Elon Musk.   (via elonenthusiast)
Posted 5 months ago

neurosciencestuff:

Literacy depends on nurture, not nature

A University at Buffalo education professor has sided with the environment in the timeless “nurture vs. nature” debate after his research found that a child’s ability to read depends mostly on where that child is born, rather than on his or her individual qualities.

“Individual characteristics explain only 9 percent of the differences in children who can read versus those who cannot,” says Ming Ming Chiu, lead author of an international study that explains this connection and a professor in the Department of Learning and Instruction in UB’s Graduate School of Education. 

“In contrast, country differences account for 61 percent and school differences account for 30 percent,” Chiu says.

Therefore, he concludes, the country in which a child is born largely determines whether he or she will have at least basic reading skills. It’s clearly a case where “nurture” — the environment and surroundings of the child — is more important than “nature” — the child’s inherited, individual qualities, according to Chiu.

More than 99 percent of fourth-graders in the Netherlands can read, but only 19 percent of fourth-graders in South Africa can read, Chiu notes.

“Although the richest countries typically have high literacy rates exceeding 97 percent,” he says, “some rich countries, such as Qatar and Kuwait, have low literacy rates — 33 percent and 28 percent, respectively.”

The study, “Ecological, Psychological and Cognitive Components of Reading Difficulties: Testing the Component Model of Reading in Fourth-graders Across 38 Countries,” analyzed reading test scores of 186,725 fourth-graders from 38 countries, including more than 4,000 children from the U.S. Chiu and co-authors Catherine McBride-Chang of the Chinese University of Hong Kong and Dan Lin of the Hong Kong Institute of Education published the study in the winter 2013 issue of the Journal of Learning Disabilities.

The educators used data from the Organization for Economic Cooperation and Development’s Program for International Student Assessment.

Besides showing that the country of origin was a better predictor of reading skills than individual traits, the study also showed that other attributes at the child, school and country levels were all related to reading.

First, girls were more likely than boys to have basic reading skills, Chiu says. Children with greater early-literacy skills, better attitudes about reading or greater self-confidence in their reading ability also were more likely to have strong basic reading skills.

“Children were more likely to have basic reading skills if they were from privileged families, as measured through socioeconomic status, number of books at home and parent attitudes about reading,” says Chiu. “Also, children attending schools with better school climate and more resources were more likely to have basic reading skills.

“Our U.S. culture values ‘can-do’ individualism, but we forget how much depends on being lucky enough to be born in the right place,” he says.