Learning Tips for Students

A lot of things have changed. Today's children have bigger syllabi to learn. Now, learning experts and teachers ask students to read faster and grasp important points.

Here are a few tips for students who have a lot to learn, but very little time.

Make a Timetable

Your timetable should have separate time for eating, playing games, exercise, reading newspaper and study materials. You should not only make a timetable, but also should stick to it.

Give priority to leisure and games in the afternoon, but separate early morning time for studies. Make sure you read all the class notes before you go to bed.

While allotting time to different subjects, allot more time to difficult subjects. You need only less time for the subjects that are easier for you to learn.

Taking Notes

Taking notes is an important part of learning. You need to take lecture notes (classroom notes) and notes from your textbook.

- Go through the lessons on the day before your teacher would teach it in the class. This gives you an idea of what to expect.

- Write down important ideas as bullet points. One word or a phrase is enough to include an idea.

- Give prominence to important ideas by underlining them in your notes.

- Leave lot of space in each face of paper. This will help you add new points later.

- Organize your notes into separate files. Each subject should have a different file. Label the outer page of the file with name of the subject and your teacher. You should also neatly organize each file according to chapters and topics.

- Read the notes (important points) in the night, before going to bed. Read only once. This helps you memorize the lessons clearly.

- While taking notes from a book, label the name of the book and author. Also, note the page number next to your notes. It makes it easy for you to refer to the book three or six months later.

Reading Techniques

You need to read fast and grasp more things. Here are some pointers to fast reading.

- Note the name of the book and its author in the reading log.

- Take a quick look from cover to cover to identify the important chapters.

- Take a quick look over the chapter, identify the important points, and note them down.

- Read the lesson fast. To increase the speed of learning, pass your eyes through the top of the letters and not through the centre. For example, while reading, pass your eyes through the area where the dot above the letter i appears and not through the loop of the letter o.

- Don't take notes while reading.

- Don't go back to read a word or a sentence. If you don't get the idea of the subject, you can come back to the sentence after you finish reading the chapter. Never look up a dictionary while in the middle of reading a chapter. Refer dictionary only if you don't automatically understand the meaning of a word after finishing the paragraph and the chapter.

- Note down the points you remember. Now check if you have taken all the important points, with another fast reading.

How to increase memory

Try to understand completely what you read or hear.

Repeat what you hear or read in your mind.

Make notes of what you learn at school or read from books. A single word can help you remember a whole idea.

Give number to the points

Don't try to bring to memory all the things you have learned. Learn the technique of bringing to memory one thing at a time.

How to increase concentration

Mental concentration is important to memory and better learning.

Stick to your reading timetable. You should separate a specific place and specific time of the day for reading.

Sit erect. It increases your concentration.

Don't allow disturbances like phone calls, music etc while reading.

Concentrate on the lessons you read. Don't think about the next book you have to read while you are reading a book. A better way is to make an order of the books and lessons to read and arrange them in order before you start reading.

Immediately after reading a paragraph, try to recall the idea from that paragraph. This helps you concentrate more on your reading.

Ideal conditions for reading/learning

A silent location that you don't use for sleeping, eating or leisure purposes is the most ideal condition for reading.

Install a fluorescent tube light in the reading room. This helps mild light to fall evenly all over the room. Don't sit in the darkness while reading. If you use table lamp, arrange it towards your left if you are a right-hander.

Arrange the papers, pencils, boards and books on the table before you start reading.

Never try to read while you are tired or ill.

Eat healthy food rich in carbohydrates, proteins and fibres. Replace fast food, pizza, burger, chocolates, ice creams, etc with fresh fruits, whole grain food items (like chapatti), milk, fruit juices, etc.

Exercise daily. Swimming, cycling and jogging are good for students. Practise yoga. It increases concentration and willpower.

Don't watch TV. Instead, play some games in the outdoors. While TV makes you dumb, the games make you smarter.

Read lot of books. Read classic stories, fables (like Aesop fables, Panchatantra stories, etc), etc. Don't spend too much time on comic cartoons.

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Courtesy http://www.streetdirectory.com

Textbooks published by the Department of School Education, Govt. of Tamil Nadu are hosted in this website for viewing purpose.

http://www.textbooksonline.tn.nic.in/

http://dge.tn.gov.in/schoolsyllabus/

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Boosting bacteria in drinking water may improve health

Every gallon of purified drinking water is home to hundreds of millions of bacteria. Water treatment facilities try to remove them – but perhaps encouraging some of the microbes to grow could benefit human health.

Lutgarde Raskin of the University of Michigan in Ann Arbor says that workers at water treatment facilities across the US try to destroy all of the bacteria in drinking water with infusions of chlorine and other disinfectants. But this is nearly impossible to achieve with the current technology.

The present approach also ignores the fact that the drinking water microbiome contains some bacteria that can be beneficial. For instance, nitrates that can contaminate drinking water could be converted by some bacteria into harmless nitrogen gas. Raskin and her team suggest that encouraging the growth of these bacteria in drinking water could actually improve the quality and safety of the product.

Between April and October 2010, the researchers analysed bacterial DNA in drinking water treated at municipal facilities in Ann Arbor. They wanted to work out exactly which bacteria were present, and what factors influenced the abundance of the various components of the bacterial community.

They found that slightly altering the water's pH during the filtration process, or even changing how filters were cleaned, helped good bacteria outcompete more harmful microorganisms for the limited resources in the water.

"It does no good to try to remove bacteria entirely," says Raskin. "We are suggesting that a few simple changes can be made that will give bacteria that are good for human health an edge over harmful competitors."
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Courtesy New Scientist

Logic blooms with new 11-set Venn diagram

A new rose has blossomed in the garden of mathematics: a flowery Venn diagram for 11 sets of objects.

Venn diagrams use overlapping circles to show all possible relationships between sets. But diagrams for more than two or three sets often require circles to be stretched, squeezed and turned in on themselves to cover the increased number of set relationships.

Such geometrical gymnastics were distasteful to British logician John Venn, who created the diagrams in 1880. What's more, the results of these mathematical acrobatics tend to be too elaborate to be useful.

So, instead, mathematicians hunt for symmetrical diagrams, which are easier to understand and are proven to exist only for Venn diagrams with a prime number of sets. For purity's sake, these diagrams must also be "simple", meaning no more than two curves cross at any point.

Lucky strike

Previously, examples for simple, symmetric Venn diagrams with five and seven sets had been found – but no higher. Now Khalegh Mamakani and Frank Ruskey at the University of Victoria in British Columbia, Canada, have hit on the first simple, symmetric 11-set Venn diagram (pictured).

One of the sets is outlined in white, and the colours correspond to the number of overlapping sets. The team called their creation Newroz, Kurdish for "the new day". The name also sounds like "new rose" in English, reflecting the diagram's flowery appearance.

To find the rose-like diagram, the pair had to comb through myriad potential diagrams, represented as lists of numbers corresponding to the way the curves cross. Sifting through all of the possibilities for an 11-set diagram would be an impossible task even for the combined might of Earth's computers, so the researchers narrowed the options by restricting the search to diagrams with a property called crosscut symmetry, meaning that a segment of each set crosses all the other sets exactly once.

Hardcore geometer

The same method has been used to find simple, symmetric seven-set diagrams. Still, the researchers knew there were no guarantees of success. "After searching for them for so long, the big surprise was to find one at all," says Ruskey.

"I love the picture," says Peter Cameron , a mathematician at Queen Mary, University of London. He says the computational techniques used to find Newroz might prove useful in representing other complex geometric objects.

However, the diagram itself is unlikely to have direct practical applications. "We use two and three-set Venn diagrams for working out simple logical puzzles," Cameron says. "Beyond that, I don't think anyone but the most hardcore geometer would use a Venn diagram."
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Courtesy New Scientist

Synthetic 'upgrade' for fruit fly's DNA

The genetic code of the fruit fly Drosophila has been hacked into, allowing it to make proteins with properties that don't exist in the natural world. The advance could ultimately lead to the creation of new or "improved" life forms in the burgeoning field of synthetic biology.

The four letters of the genetic code, A, C, T and G, are read in triplets, called codons, by the cell's protein-making machinery. Each codon gives an instruction for the type of amino acid that gets added next in a protein chain, or tells the machinery to stop.

Jason Chin at the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK, and colleagues previously showed that it was possible to reassign one of these stop codons to incorporate an "unnatural" amino acid instead, and last year they engineered nematode worms to manufacture such proteins.

Complex proposition

However, fruit flies are a much more complex proposition. "They contain significantly more neurons; they can learn; they have all sorts of complicated behaviours," says Chin. "Many of the things we've discovered in biology have actually been discovered in flies."

Now, as a proof of principle, Chin's team has engineered fruit flies that incorporated three new amino acids into proteins in the cells of their ovaries.

The flies were engineered using bacteria that had been modified to insert the genetic code for the unnatural amino acid into the fly DNA. There was no apparent impact on the flies' health, and they even produced healthy offspring that also made the new protein chains.

"This work provides a very significant expansion on our capability to manipulate and alter proteins involved in specific cellular and developmental processes. It will provide new insights into human disease mechanisms, memory and ageing," says Paul Freemont of the Centre for Synthetic Biology and Innovation at Imperial College London.

Bulletproof flies

None of the amino acids were particularly remarkable, but the fact that engineering the flies had no obvious impact on their health suggests that many more useful amino acids could be similarly incorporated.

For example, work in bacterial cells has shown that it is possible to incorporate unnatural amino acids that cross-link to each other or turn an enzyme's activity on or off when a light is shone on them. Doing this in a complex organism like a fly could shed new light on how proteins interact within cells, or how rapidly turning an enzyme on or off affects the cell's function.

The technique could even be used to create animals with new or improved properties, although that is probably some years off. "We're not going to be creating bulletproof flies or anything like that in the short term," says Chin.
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Courtesy New Scientist

Mathematics is as rich as literature

Many gifted writers have attempted to translate mathematical thinking into terms ungifted readers can understand. Daniel Tammet's unassuming new volume of essays, reminiscences and stories reveals the enormity of their failure. Thinking in Numbers is unprecedented: a pitch-perfect duet between mathematics and literature. More than that: it is a hybrid. Something new.

Thinking in Numbers reflects Tammet's career-long refusal to accept that mathematical imaginings are somehow special, abstruse, removed from human reality. A synaesthete, a polyglot and a memory man - he once recited pi to 22,514 decimal places, setting a European record - Tammet insists his highly functioning autistic mind is normal. The differences, such as they are, between his thoughts and most other people's are to do with the kind of attention he brings to the world. Numbers have texture, colour and character. Whether we pay attention to these qualities, explore them and enjoy them, is a little bit to do with our genetic inheritance, much more to do with our schooling, and ultimately down to personal choice.  All of us think mathematically all the time. To be "afraid of numbers" is a pose, a position, an aesthetic choice, as surely as not "getting" jazz, or condemning this or that kind of art as "rubbish".

For a book that shines a bitterly bright light on our cultural philistinism, there is a surprising lack of didacticism here, and not a squeak of bad temper. These essays are by turns playful and confessional (as when Tammet, the man with the supposedly supercharged brain, singularly fails to predict the simplest actions of his own mother). There are several virtuosic performances. (Noticing that Shakespeare would have been one of the first English schoolchildren to learn about zero, Tammet reinterprets and elucidates some of the poet-playwright's most powerful and moving verse.) But Tammet, though he appreciates the stage magician's art, is not a natural showman. He prefers persuasion, conversation and the recording of subtleties.

The mathematics in his stories is often very simple indeed, as when he observes, with intense attention and compassion, how a friend struggles with and finally solves a trivia puzzle. One senses Tammet's loneliness at these moments: he inhabits a world of great variety and beauty, but gets pitifully few visitors. We do not approach novels, or even poetry, as timorously as we approach mathematics, though Tammet convincingly demonstrates that the three forms are very closely related, with bonds far stronger and more demonstrable than those that supposedly bind maths to music.

Elsewhere Tammet inclines towards slightly melancholy subjects: the ephemerality of snowflakes; the vain idealism that fuels the creation of unbuildable cities; the self-deceptions sewn through Frank Drake's scientific-looking formula, asserting the chances of there being other intelligent life in the universe.

Thinking in Numbers is not about mathematics per se. It is about the mathematical component of lived experience. It is about the curious sensual ways we measure the world (for example, the preponderance of G-words "to describe things which are 'great', or 'grand', 'gross' or 'gargantuan'"); the littleness of the individual in the face of pi; the rhetorical satisfactions of a well-turned theorem; the primes that power certain kinds of poetry.

Mathematics, Tammet says, is illimitable. It is a language through which the human imagination expresses itself. Presumably this means mathematics has, or deserves, a literature.  In Tammet, it already has a laureate.

Courtesy New Scientist www.edufine.net

Holding on to faulty protein delays brain degeneration

When something goes wrong in your brain, you'd think it would be a good idea to get rid of the problem. Turns out, sometimes it's best to keep hold of it. By preventing faulty proteins from being destroyed, researchers have delayed the symptoms of a degenerative brain disorder.

SNAP25 is one of three proteins that together make up a complex called SNARE, which plays a vital role in allowing neurons to communicate with each other. In order to work properly, all the proteins must be folded in a specific way. CSP alpha is one of the key proteins that ensures SNAP25 is correctly folded.

Cells have a backup system to deal with any misfolded proteins – they are destroyed by a bell-shaped enzyme called a proteasome, which pulls the proteins inside itself and breaks them down.

People with a genetic mutation that affects the CSP alpha protein – and its ability to correctly fold SNAP25 – can develop a rare brain disorder called neuronal ceroid lipofuscinosis (NCL). The disorder causes significant damage to neurons – people affected gradually lose their cognitive abilities and struggle to move normally.

To find out what role proteasomes might play in NCL, Manu Sharma and his colleagues at Stanford University in California blocked the enzyme in mice that were bred to lack CSP alpha. "We weren't sure what would happen," says Sharma. Either the misfolded SNAP25 would accumulate and harm the cells, or some of the misfolded proteins may work well enough to retain some of their function.

Longer life

It appears it was the latter. Mice bred to lack CSP alpha suffer the same physical and cognitive problems as humans, and tend to survive for about 65 to 80 days, rather than the normal 670 days. But mice injected with a drug that blocked protease lived, on average, an extra 15 days. "Fifteen days might not sound like much, but as a percentage it's quite significant," says Sharma. What's more, treated mice were able to stave off measurable movement and cognitive symptoms for an extra 10 days.

The finding goes against the idea that neurodegenerative disorders should be treated by clearing away misfolded proteins, rather than trying to rescue their function. "People normally think that protease isn't working hard enough," says Nico Dantuma at the Karolinska Institute in Stockholm, Sweden, who was not involved in the study.

But whether or not the drugs are likely to work in other neurodegenerative disorders involving aggregations of misfolded proteins, such as Alzheimer's and Parkinson's disease, is up for debate. "I don't think their results prove that clearing misfolded proteins is not a useful therapeutic," says Ana Maria Cuervo at Albert Einstein College of Medicine in New York. Other studies that increase the degrading of misfolded proteins have been shown to improve symptoms in other neurodegenerative diseases, she says.

"There are two sides of the coin," says Dantuma. "You might rescue functioning proteins from being degraded... but it's too early to extrapolate these results to Alzheimer's and Parkinson's disease."

In the meantime, drugs that block proteasome are already used to treat cancer, so Sharma hopes they can soon be trialled in people with NCL.

Courtesy New Scientist
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Self-cooling crystal makes room-temperature maser

Trading rubies for artificial look-a-likes might seem like a bad idea. But that could be what finally turns masers into valuable technology, ranging in application from medical imaging to chemical sensors.

First dreamed up in the 1950s, the maser is a precursor to the now ubiquitous laser that emits concentrated microwave radiation instead of visible light.

Although masers have been shown to amplify signals with little background noise, conventional solid-state masers work only under extreme conditions, such as in a vacuum or at temperatures near absolute zero. Masers also need strong magnetic fields to function.

Cryogenically cooled ruby masers have been used in antennas to boost the microwave signals from deep space missions such as NASA's Voyager probes. But for the most part, lasers have outpaced their predecessors here on Earth.

Now, using a pink crystal grown from hydrocarbons – p-terphenyl doped with pentacene – Mark Oxborrow of the UK's National Physical Laboratory and colleagues have created the first maser that works in air at room temperature and with no added magnetic field.

Inner beauty

Oxborrow and his team exploited a phenomenon called inter-system crossing, found to occur in pentacene, which produces a very cold system even while at room temperature. This allows the maser to work as though it's operating within thousandths of a degree of absolute zero.

The truly remarkable thing about this "internal refrigerator" is that with it, the maser's microwave emission is even greater at room temperatures than one under cryogenic conditions, says Oxborrow.

Aharon Blank, an associate professor at the Israel Institute of Technology, came close to making room-temperature masers 10 years ago. Although enthusiastic about Oxborrow's work, he points out that the new maser can only operate for pulses of about 300 microseconds.

"One needs to have continuous operation for most applications, so this very important aspect is still missing," says Blank.

Oxborrow concedes the limitations of his research, but he's confident that renewed interest in masers could lead to significant advances.

"Through modest investment there is scope for substantial improvements," he says.

Courtesy New Scientist

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“That’s one small step for man, one giant leap for mankind,”

Neil Armstrong was a quiet, self-described “nerdy” engineer who became a global hero when as a steely-nerved U.S. pilot he made “one giant leap for mankind” with the first step on the moon. The modest man who entranced and awed people on Earth has died. He was 82.

Armstrong died following complications resulting from cardiovascular procedures, a statement from his family said Saturday. It didn’t say where or when he died.

Armstrong commanded the Apollo 11 spacecraft that landed on the moon July 20, 1969, capping the most daring of the 20th century’s scientific expeditions. His first words after setting foot on the surface are etched in history books and in the memories of those who heard them in a live broadcast.

“That’s one small step for man, one giant leap for mankind,” Armstrong said.

In those first few moments on the moon, during the climax of a heated space race with the then—Soviet Union, Armstrong stopped in what he called “a tender moment” and left a patch to commemorate NASA astronauts and Soviet cosmonauts who had died in action.

“It was special and memorable, but it was only instantaneous because there was work to do,” Armstrong told an Australian television interviewer this year.

Armstrong and Buzz Aldrin spent nearly three hours walking on the lunar surface, collecting samples, conducting experiments and taking photographs.

“The sights were simply magnificent, beyond any visual experience that I had ever been exposed to,” Armstrong once said.

The moonwalk marked America’s victory in the Cold War space race that began Oct. 4, 1957, with the launch of the Soviet Union’s Sputnik 1, a satellite that sent shock waves around the world.

An estimated 600 million people a fifth of the world’s population watched and listened to the moon landing, the largest audience for any single event in history.

Parents huddled with their children in front of the family television, mesmerized. Farmers abandoned their nightly milking duties, and motorists pulled off the highway and checked into motels just to watch on TV.

Although he had been a Navy fighter pilot, a test pilot for NASA’s forerunner and an astronaut, Armstrong never allowed himself to be caught up in the celebrity and glamour of the space program.

“I am, and ever will be, a white socks, pocket protector, nerdy engineer,” he said in February 2000 in one of his rare public appearances. “And I take a substantial amount of pride in the accomplishments of my profession.”

A man who kept away from cameras, Armstrong went public in 2010 with his concerns about President Barack Obama’s space policy that shifted attention away from a return to the moon and emphasized private companies developing spaceships. He testified before Congress, and in an email to The Associated Press he said he had “substantial reservations.”

Armstrong’s modesty and self-effacing manner never faded.

When he appeared in Dayton, Ohio, in 2003 to help celebrate the 100th anniversary of powered flight, he bounded onto a stage before 10,000 people. But he spoke for only a few seconds, did not mention the moon and quickly ducked out of the spotlight.

“Thank you, John. Thirty-four years?” Armstrong quipped, as if he hadn’t given it a thought.

At another joint appearance, the two embraced and Glenn commented- “To this day, he’s the one person on Earth, I’m truly, truly envious of.”

Armstrong’s moonwalk capped a series of accomplishments that included piloting the X-15 rocket plane and making the first space docking during the Gemini 8 mission, which included a successful emergency splashdown.

In the years afterward, Armstrong retreated to the quiet of the classroom and his Ohio farm. Aldrin said in his book “Men from Earth” that Armstrong was one of the quietest, most private men he had ever met.

In the Australian interview, Armstrong acknowledged that “now and then I miss the excitement about being in the cockpit of an airplane and doing new things.”

At the time of the flight’s 40th anniversary, Armstrong again was low-key, telling a gathering that the space race was “the ultimate peaceful competition- USA versus U.S.S.R. It did allow both sides to take the high road, with the objectives of science and learning and exploration.”

Glenn, who went through jungle training in Panama with Armstrong as part of the astronaut program, described him as “exceptionally brilliant” with technical matters but “rather retiring, doesn’t like to be thrust into the limelight much.”

Derek Elliott, curator of the Smithsonian Institution’s U.S. Air and Space Museum from 1982 to 1992, said the moonwalk probably marked the high point of space exploration.

“The fact that we were able to see it and be a part of it means that we are in our own way witnesses to history,” he said.

The 1969 landing met an audacious deadline that President John F. Kennedy had set in May 1961, shortly after Alan Shepard became the first American in space with a 15-minute suborbital flight. Soviet cosmonaut Yuri A. Gagarin had orbited the Earth and beaten the U.S. into space the previous month.

“I believe this nation should commit itself to achieving the goal, before the decade is out, of landing a man on the moon and returning him safely to Earth,” Kennedy had said. “No single space project in this period will be more impressive to mankind, or more important to the long-range exploration of space; and none will be so difficult or expensive to accomplish.”

The end-of-decade goal was met with more than five months to spare. “Houston- Tranquility Base here,” Armstrong radioed after the spacecraft settled onto the moon. “The Eagle has landed.”

“Roger, Tranquility,” the Houston staffer radioed back. “We copy you on the ground. You’ve got a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”

The third astronaut on the mission, Michael Collins, circled the moon in the mother ship Columbia while Armstrong and Aldrin went to the moon’s surface.

In all, 12 American astronauts walked on the moon between 1969 and the last moon mission in 1972.

For Americans, reaching the moon provided uplift and respite from the Vietnam War. The landing occurred as organizers were preparing for Woodstock, the legendary rock festival on a farm in New York.

Armstrong was born Aug. 5, 1930, on a farm in Ohio. He took his first airplane ride at age 6 and developed a fascination with aviation that prompted him to build model airplanes and conduct experiments in a homemade wind tunnel. He was licensed to fly at 16, before he got his driver’s license.

Armstrong enrolled in Purdue University to study aeronautical engineering but was called to duty with the U.S. Navy in 1949 and flew 78 combat missions in Korea. After the war, Armstrong finished his degree and later earned a master’s degree in aerospace engineering from the University of Southern California. He became a test pilot with what evolved into the National Aeronautics and Space Administration, flying more than 200 kinds of aircraft from gliders to jets.

Armstrong was accepted into NASA’s second astronaut class in 1962 the first, including Glenn, was chosen in 1959 and commanded the Gemini 8 mission in 1966. After the first space docking, he brought the capsule back in an emergency landing in the Pacific Ocean when a wildly firing thruster kicked it out of orbit.

Armstrong was backup commander for the historic Apollo 8 mission at Christmastime in 1968. In that flight, Commander Frank Borman, and Jim Lovell and Bill Anders circled the moon 10 times, and paving the way for the lunar landing seven months later.

Aldrin said he and Armstrong were not prone to free exchanges of sentiment.

“But there was that moment on the moon, a brief moment, in which we sort of looked at each other and slapped each other on the shoulder ... and said, ‘We made it. Good show,’ or something like that,” Aldrin said.

In Wapakoneta, media and souvenir frenzy was swirling around the home of Armstrong’s parents.

“You couldn’t see the house for the news media,” recalled John Zwez, former manager of the Neil Armstrong Air and Space Museum. “People were pulling grass out of their front yard.”

Armstrong, Aldrin and Collins were given ticker tape parades in New York, Chicago and Los Angeles and later made a 22-nation world tour. A homecoming in Wapakoneta drew 50,000 people to the city of 9,000.

In 1970, Armstrong was appointed deputy associate administrator for aeronautics at NASA but left the following year to teach aerospace engineering at the University of Cincinnati.

“He didn’t give interviews, but he wasn’t a strange person or hard to talk to,” said Ron Huston, a colleague at the University of Cincinnati. “He just didn’t like being a novelty.”

In February 2000, when he agreed to announce the top 20 engineering achievements of the 20th century as voted by the National Academy of Engineering, Armstrong said there was one disappointment relating to his moonwalk.

“I can honestly say and it’s a big surprise to me that I have never had a dream about being on the moon,” he said.

Armstrong married Carol Knight in 1999. He had two adult sons from a previous marriage.

At the Griffith Observatory in Los Angeles on Saturday, visitors held a minute of silence.

Courtesy The Hindu
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Nutrient-boosted foods protect against blindness

THERE'S a new weapon in the battle against blindness, and it's bright orange. A sweet potato bred naturally to contain loads more beta carotene than its traditional counterparts has helped stave off vitamin A deficiency in thousands of Ugandans. The announcement comes as other results confirm that beta-carotene-packed genetically modified rice can also boost dietary vitamin A effectively. Beta carotene is converted into vitamin A in the body.

About half a million children in Africa and Asia go blind every year because their diet contains too little vitamin A, which is vital for vision and the immune system. Of those who lose their sight, two-thirds die within months.

Aid agencies currently treat the deficiency by giving children high-dose capsules of vitamin A twice a year, but supplying the missing vitamin through locally grown food would be more practical and sustainable.

Enter the sweet potato. The orange flesh of a standard sweet potato betrays its beta-carotene content - the same stuff responsible for the carrot's hue. The new strain has four to six times the beta-carotene of an average sweet potato.

A two-year project involving 10,000 households in Uganda found that vitamin A intake doubled in women and in children aged 6 to 35 months who ate the improved sweet potatoes compared with families that continued eating regular varieties. By the end of the project almost 90 per cent of the kids eating the new strain had escaped vitamin A deficiency, compared with just 50 per cent in a control group.

"There's great potential for these potatoes," says Christine Hotz of the International Food Policy Research Institute in Washington DC, who headed the Ugandan project (Journal of Nutrition, DOI: 10.3945/jn.111.151829).

More controversial than the naturally bred sweet potatoes is Golden Rice - genetically engineered to contain 30 micrograms of beta-carotene per gram. Ordinary rice has none.

Critics had claimed that the rice is impractical. According to calculations by Greenpeace, people would need to eat huge amounts - as much as 18 kilograms of cooked rice a day - to obtain enough vitamin A.

A study involving 68 Chinese children demolishes the criticism. Guangwen Tang of Tufts University in Boston, Massachusetts, and colleagues have demonstrated that just 100 to 150 grams of the rice - about half the children's daily intake - provided 60 per cent of the recommended daily intake of vitamin A.

The children were given beta-carotene either in the rice, in pure form in oil, or in spinach. All the beta carotene they received contained isotopes enabling any vitamin A made from it to be distinguished from vitamin A that was already circulating in their blood.

Analyses showed that it took 2.3 grams of beta-carotene derived from rice to make a single gram of vitamin A - only marginally less efficient than making it from oil, which took 2 grams (American Journal of Clinical Nutrition, DOI: 10.3945/ajcn.111.030775).

"The conversion rate can't get better than that," says Adrian Dubock, project manager for the Golden Rice Project. He hopes that Golden Rice will eventually become widely available, despite objections. "It's been a long haul, but the new results give us confidence we're on the right track," he says.

Courtesy New Scientist

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'Cold' solar loops may help solve corona puzzle

THE surface of the sun is a pretty cool place. At least when you compare it with the corona, the sun's upper atmosphere, which is nearly 400 times hotter.

This huge temperature difference has long been a mystery, but a newly discovered feature of the sun's magnetic field may help us get to the bottom of things.

The sun's tangled magnetic field includes huge loops that arch from the surface into the corona. We can see the loops because bright surface plasma flows along their curves.

Richard Frazin at the University of Michigan, Ann Arbor, and his team were measuring the temperature of coronal loops during a solar minimum, a quiet phase which sees fewer sunspots and flares. They expected all loops to get hotter with height, since that was the case in measurements taken during more active phases.

Surprisingly, some of the loops nearest the sun's equator got colder near their tops. Frazin thinks these newly found "down loops" exist throughout the solar cycle and may be a symptom of whatever causes coronal heating (The Astrophysical Journal, DOI: 10.1088/0004-637x/755/2/86).

Clare Parnell at the University of St Andrews, UK, agrees that down loops are a new factor that any solar-heating model will need to include.

Courtesy New Scientist
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Bendable teeth seen for the first time

TEETH are typically the hardest material in the body, but not so for some suckermouth catfish (Loricariidae). Their pearly whites do something wholly untoothy: bend.

Adaptations to avoid broken or chipped teeth are common enough - the teeth of sharks and rays, for example, are slightly loose. But this is the first published report of bendable teeth. It makes sense for catfish to have them, though, since they scrape food off rocks and other hard surfaces with their mouths - a habit that could easily break rigid teeth.

TomGeerinckx, an evolutionary morphologist at Ghent University in Belgium, extracted teeth from five species of scraping suckermouth catfish and analysed their composition and microstructure. He found that each tooth had a bendable section containing more collagen and significantly less calcium, phosphate and magnesium than the rest of the tooth. The work will appear in Physiological and Biochemical Zoology.

"[The] teeth are very long and skinny and they have a built-in section that's flexible. That's absolutely mind-blowing," says Peter Wainwright of the University of California, Davis.

Such teeth may not be unique, though. Wainwright suggests they are also found in some common reef fish that feed by scraping rocks. "I've personally tweaked their teeth and holy cow, they're bendable," he says.

Courtesy New Scientist
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