kishanth

Ozone hole causing global warming?

The hole in the Earth's ozone layer may be shifting wind patterns and cloud cover in a way that triggers slightly warmer global temperatures, a new study suggests.

A lot of people mix up the ozone hole and global warming, believing the hole is a major cause of the world's increasing average temperature, researchers said.

Scientists, on the other hand, have long attributed a small cooling effect to the ozone shortage in the hole.

Now a new computer-modelling study suggests that the ozone hole might actually have a slight warming influence, but because of its effect on winds, not temperatures.

The new research suggests that shifting wind patterns caused by the ozone hole push clouds farther towards the South Pole, reducing the amount of radiation the clouds reflect and possibly causing a bit of warming rather than cooling.

"We were surprised this effect happened just by shifting the jet stream and the clouds," said lead author Kevin Grise, a climate scientist at Lamont-Doherty Earth Observatory of Columbia University in New York City.

Grise noted this small warming effect may be important for climatologists trying to predict the future of Southern Hemisphere climate.

In the 1980s, scientists discovered thinning of the ozone layer above Antarctica during the Southern Hemisphere's spring months.

An actual consequence of the ozone hole is its odd effect on the Southern Hemisphere polar jet stream, the fast flowing air currents encircling the South Pole.

Despite the ozone hole only appearing during the spring months, throughout each subsequent summer the high-speed jet stream swings south toward the pole, researchers said.

"For some reason when you put an ozone hole in the Southern Hemisphere during springtime, you get this robust poleward shift in the jet stream during the following summer season," said Grise.

"People have been looking at this for 10 years and there's still no real answer of why this happens," said Grise.

Scientists wondered if the ozone hole's impacts on the jet stream would have any indirect effects on the cloud cover. Using computer models, they worked out how the clouds would react to changing winds.

"Because the jet stream shifts, the storm systems move along with it toward the pole. If the storm systems move, the cloud system is going to move with it," said Grise.

High- and mid-level clouds travelled with the shifting jet stream toward the South Pole and the Antarctic continent. Low-level cloud coverage dropped in their models throughout the Southern Ocean, the team discovered.

When the cloud cover moves poleward, the amount of energy the clouds can reflect drops, which increases the amount of radiation reaching the ground, researchers said.

The study was published in the journal Geophysical Research Letters.

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Melatonin is produced naturally in the human body by the pineal gland in the brain. When your eye sends signals to the brain that night is falling, the pineal gland is activated to produce melatonin. Melatonin then works to induce feelings of drowsiness, acting as the signal to your body that it’s time for bed. However, melatonin production can be suppressed by artificial nighttime lighting. The pineal gland is connected to sensors in the eye via a network of nerve fibers. When light is not striking the eye, the pineal gland is able to produce melatonin. When light is present, melatonin production is suppressed. Artificial nighttime lighting can have a harmful effect on your body, as the production of the hormone melatonin is reduced and your body does not receive effective signals to slow down and prepare for a night of restorative sleep.

SleepWell specs help to boost your natural production of melatonin. The special, coated lenses fitted in every pair of SleepWell specs, block the specific blue spectrum of light which receptors in your eyes use to signal the pineal gland to inhibit melatonin production. By effectively filtering these wavelengths of blue light, SleepWell specsswitch your pineal gland into its melatonin production mode causing your body to prepare for sleep and rejuvenation.

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Studies have shown that the photoreceptors (or light sensors) in the pineal gland are most sensitive to light in the blue part of the spectrum. This is because when blue light hits the eye, these photoreceptors are receiving the message that it is daylight and the brain should stay awake and alert. Ever since Thomas Edison invented the first commercially practical light bulb, our eyes have been exposed to artificial lighting long after darkness has fallen. This has been compounded in more recent years with harsh fluorescent light from the television and computer screens we look at during the evening. All of this has an effect on our body’s natural circadian rhythms. More specifically, blue light continues to hit those photoreceptors hours after night has fallen, and our pineal gland does not get the message to switch into melatonin production mode and trigger the physiological signs that we need to sleep. But if we prevent blue light from hitting those sensors, the pineal gland can be activated to produce melatonin.

"SleepWell specs are a natural, safe and effective way to boost melatonin production prior to bedtime."

SleepWell specs have specially filtered lenses which block the wavelength of light that is picked up by sensitive photoreceptors in the pineal gland. By preventing this wavelength of blue light from reaching the pineal gland, the sensors in the pineal gland are fooled into thinking we are in darkness which convinces your pineal gland to switch into melatonin production mode.

Researching the effects of light on melatonin production

Tests have conclusively proven that different light wavelengths have different effects on the body’s melatonin production.

In a test performed in 2001 by Debra Skene at the University of Surrey, light was shone into volunteers’ eyes in the middle of the night, when melatonin production levels are at their peak. Melatonin production was found to be clearly sensitive to light: production levels decreased as light intensity increased. However, what was interesting was that the different wavelengths of light produced different results. The shortest wavelengths, what we see as dark blue, caused the greatest drop in melatonin. What is particularly interesting is that the rods and cones in the retina barely detect this wavelength of light.

"Skene concluded that there must be a third, still unknown type of photoreceptor that tells the brain when to stop making melatonin"

A further study in 2002, by David Berson of Brown University, went on to confirm that a new type of photoreceptor existed. Berson described them as a type of retinal ganglion cell. These cells extend long projections into a part of the brain called suprachiasmatic nucleus (SCN). They transmit information directly from the eyes into the region of the brain that regulates the circadian clock These photoreceptors are the sensor in the pineal gland that receive the blue light, which signals to the pineal gland to stop producing melatonin.

What these tests found was that there are two completely separate systems in operation in our eyes. One, using rods and cones, allows us to see things. The second controls the release of melatonin. The photoreceptors receive information directly from the eye to the part f the brain that regulates our body clock, or circadian rhythm.

In 2003 it was confirmed by Lockley et al that the shorter wavelengths of light have a greater effect on melatonin production. The short 460 nanometres (nm) wavelengths of light suppress melatonin twice as much as longer 555 nm light, the wavelength best seen my the human eye.

"It was demonstrated that if we can control the wavelengths of light reaching the eye, we can control our internal clocks"

In 2005 Christian Cajochen at University Basel in Switzerland, successfully reset the circadian clocks of test subjects through the use of colored lights. Test subjects were exposed to indigo-blue light with a wavelength of 460 nm, green-yellow light with a wavelength of 550 nm, or complete darkness. The researchers then monitored each subject’s sleep / wake cycle. Subjects in complete darkness showed normal nighttime trends of reduced core-body temperatures, slower heart rates, higher melatonin production and increased sleepiness. Exposing subjects to the indigo-blue light suppressed melatonin production and other normal nighttime trends. Green-yellow light had a minimal effect.

In 2007 a further study by Farhan Zaidi et al, at the imperial College London concluded that there are two separate functional light sensing systems in the eye: one for vision, and one for setting our sleep / wake pattern. Blind people who lack rods and cones in their eyes but still have functional blue light sensitive ganglion in their eyes were still able to unconsciously sense whether it was light or dark by detecting blue light. By shining a light in their eyes, the researchers were able to delay the subjects’ body clock cycle, proving that their ganglion cells still registered light. The blue light caused melatonin production to drop by 60%, while at the same time alertness sharpened and brain activity increased, demonstrating that the body clock had been tricked into thinking it was daytime.

The wavelength of 480 nm which the retinal ganglia are so sensitive to, is in the blue spectrum. In fact, it is very similar to the color of the sky on a bright sunny day. Bright lights, especially blue lights, tell our brain that it is morning. Thus if we can filter out that wavelength of blue light, we can fool our brain that it is night. Wearing SleepWell specsat night prevents the nighttime suppression of melatonin caused by an environment of artificial lighting. Wearing SleepWell specs for 3 hours prior to bed is an effective way to stimulate melatonin production. It can be as easy as wearing them for your nighttime reading.

"SleepWell specs are the natural solution to a modern problem"

Sleep Well specs work by filtering the specific wavelengths of light that are responsible for shutting down melatonin production in the brain. Recent discoveries have demonstrated that if light contains only wavelengths greater than 530mn, such light will not suppress melatonin production in bright-light conditions.

SleepWell specs contain prescription grade CR39 lenses and are currently the ONLYeyewear available in the world that correctly filter these distruptive wavelengths.

Trouble concentrating, sleeping problems, low energy levels and mood are controlled by the chemicals within our bodies. It all comes down to chemistry.

Wearing SleepWell specs leading up to bedtime will allow the natural production of melatonin in your body and dramatically improve your sleep.

சோதனைக் குழாய் குழந்தை முறையை கண்டுபிடித்த விஞ்ஞானி ராபர்ட் எட்வர்ட்ஸ் காலமானார்

       உலகில் அறிவியல் வளர்ச்சியின் முக்கியச் சாதனையாக கருதப்படும் சோதனைக் குழாய் குழந்தை முறையை கண்டுபிடித்த விஞ்ஞானி ராபர்ட் எட்வர்ட்ஸ் (Robert Edwards) காலமானார்.

87 வயதான அவர் நீண்டகாலமாக உடல்நலக் குறைவால் பாதிக்கப்பட்டிருந்தார். இந்நிலையில், நேற்று தூக்கத்திலேயே அவரது உயிர் பிரிந்தது. அவரது அறிவியல் கண்டுபிடிப்பால் செயற்கை கருவூட்டல் முறையில், 1978-ம் ஆண்டு உலகின் முதல் சோதனை குழாய் குழந்தை பிறந்தது. தற்போது 35 வயதாகும் லூயிஸ் ப்ரௌன் (Louise Brown) என்னும் அந்த பெண் ராபர்ட் எட்வர்ட்ஸ் (Robert Edwards) காலமானதற்கு இரங்கல் தெரிவித்துள்ளார்.

உலகம் முழுவதும் குழந்தை இல்லாத தம்பதியினருக்கு மகிழ்ச்சியை உருவாக்கியவர் என்றும், அவரது மறைவு ஈடு செய்ய முடியாதது என்றும் லூயிஸ் ப்ரௌன் (Louise Brown) தனது இரங்கல் செய்தியில் தெரிவித்துள்ளார். சோதனைக் குழாய் குழந்தை முறையை கண்டுபிடித்ததற்காக, 2010-ல் ராபர்ட் எட்வர்ட்ஸ் (Robert Edwards)-க்கு நோபல் பரிசு வழங்கப்பட்டது.

உலகில் அறிவியல் வளர்ச்சியின் முக்கியச் சாதனையாக கருதப்படும் சோதனைக் குழாய் குழந்தை முறையை கண்டுபிடித்த விஞ்ஞானி ராபர்ட் எட்வர்ட்ஸ் (Robert Edwards) காலமானார்.

Solar Cycle Update: Twin Peaks?

http://science.nasa.gov/media/medialibrary/2013/03/01/splash2.jpg/image_full


Something unexpected is happening on the sun. 2013 is supposed to be the year of Solar Max, but solar activity is much lower than expected. At least one leading forecaster expects the sun to rebound with a double-peaked maximum later this year.

March 1, 2013: Something unexpected is happening on the sun.  2013 is supposed to be the year of Solar Max, the peak of the 11-year sunspot cycle. Yet 2013 has arrived and solar activity is relatively low.  Sunspot numbers are well below their values in 2011, and strong solar flares have been infrequent for many months.

The quiet has led some observers to wonder if forecasters missed the mark. Solar physicist Dean Pesnell of the Goddard Space Flight Center has a different explanation: 

"This is solar maximum," he suggests. "But it looks different from what we expected because it is double peaked."Conventional wisdom holds that solar activity swings back and forth like a simple pendulum.  At one end of the cycle, there is a quiet time with few sunspots and flares.  At the other end, Solar Max brings high sunspot numbers and solar storms. It’s a regular rhythm that repeats every 11 years.

Reality, however, is more complicated. Astronomers have been counting sunspots for centuries, and they have seen that the solar cycle is not perfectly regular. For one thing, the back-and-forth swing in sunspot counts can take anywhere from 10 to 13 years to complete; also, the amplitude of the cycle varies.  Some solar maxima are very weak, others very strong.

Pesnell notes yet another complication: "The last two solar maxima, around 1989 and 2001, had not one but two peaks."  Solar activity went up, dipped, then resumed, performing a mini-cycle that lasted about two years.

The same thing could be happening now.  Sunspot counts jumped in 2011, dipped in 2012, and Pesnell expects them to rebound again in 2013: "I am comfortable in saying that another peak will happen in 2013 and possibly last into 2014," he predicts.

Another curiosity of the solar cycle is that the sun's hemispheres do not always peak at the same time.  In the current cycle, the south has been lagging behind the north.  The second peak, if it occurs, will likely feature the southern hemisphere playing catch-up, with a surge in activity south of the sun's equator.

Pesnell is a leading member of the NOAA/NASA Solar Cycle Prediction Panel, a blue-ribbon group of solar physicists who assembled in 2006 and 2008 to forecast the next Solar Max. At the time, the sun was experiencing its deepest minimum in nearly a hundred years.  Sunspot numbers were pegged near zero and x-ray flare activity flat-lined for months at a time.  Recognizing that deep minima are often followed by weak maxima, and pulling together many other threads of predictive evidence, the panel issued this statement:

"The Solar Cycle 24 Prediction Panel has reached a consensus. The panel has decided that the next solar cycle (Cycle 24) will be below average in intensity, with a maximum sunspot number of 90. Given the date of solar minimum and the predicted maximum intensity, solar maximum is now expected to occur in May 2013. Note, this is not a unanimous decision, but a supermajority of the panel did agree."

Given the tepid state of solar activity in Feb. 2013, a maximum in May now seems unlikely.

"We may be seeing what happens when you predict a single amplitude and the Sun responds with a double peak," comments Pesnell.

Incidentally, Pesnell notes a similarity between Solar Cycle 24, underway now, and Solar Cycle 14, which had a double-peak during the first decade of the 20^th century. If the two cycles are in fact twins, “it would mean one peak in late 2013 and another in 2015.”

No one knows for sure what the sun will do next.  It seems likely, though, that the end of 2013 could be a lot livelier than the beginning.

Christmas Sky Show

The Moon and Jupiter are converging for a heavenly sky show on Christmas 2012. Got a telescope? Something is happening on Jupiter that makes it an extra-interesting target for backyard optics.

Dec. 21, 2012:  Just when you thought Christmas was over: At the end of the day on Dec. 25th, a pair of holiday lights will pop out of the deepening twilight. Jupiter and the Moon are having a Christmas conjunction.

It’s a beautiful apparition, visible all around the globe. Even city dwellers, who often miss astronomical events because of light pollution, can see the show. Separated by less than 2 degrees, the bright pair will beam right through urban lights.

For anyone who gets a telescope for Christmas, the timing is perfect. Jupiter and the Moon are among the most satisfying targets for backyard optics. A quick sweep of the telescope from Jupiter to the Moon and back again will reveal Jupiter's storms and cloud belts, the Moon's mountains and impact craters, and of course the four Galilean satellites circling the giant planet like a miniature solar system.

Jupiter's trademark Great Red Spot will also be on display--and it is worth a look. Astronomers recently announced that the enormous swirling storm, twice as wide as the planet Earth, is "spinning up."

Actually, explains planetary scientist Glenn Orton of NASA's Jet Propulsion Laboratory, "the Red Spot is shrinking." He likens it to "the iconic picture of a figure skater pulling her arms in to spin faster. As the size contracts, the spin rate increases."

John Rogers, head of the British Astronomical Association's Jupiter Section, noticed the phenomenon in recent pictures of Jupiter snapped by amateur astronomers. He was able to track a dark cloudy feature as it swirled three times around the Red Spot's central vortex. The circulating streak completed the circuit in only 4.0 days, shorter than the 4.5 days Rogers measured in 2006 using the same method.

Looking back in time, "the trend of decreasing rotation period has been consistent at least since Voyager visited Jupiter in 1979," says Rogers. As the spot shrinks, it also changes shape. Decades ago the Red Spot looked like a sausage – now it’s more circular.

What happens next is hard to say. "Perhaps the Red Spot will continue to shrink and eventually disappear," speculates Rogers. "Or perhaps it will be rejuvenated if some new storm arises to reinforce it."

One thing is certain, Christmas night is a good time to look. The Red Spot will be transiting Jupiter's middle for observers across North America and will be perfectly positioned for telescopic observations.

But you don't need a telescope to enjoy the show. Step outside at sunset on Dec. 25th and look east. After all, Christmas isn't really over until you've seen the holiday lights.

செவ்வாய் கிரகத்தில் உயிரினங்கள் இருந்ததற்கான வாய்ப்புகள் இருப்பதாக அமெரிக்க விண்வெளி ஆராய்ச்சி நிறுவனமான நாசா கூறியுள்ளது. செவ்வாய் கிரகத்துக்கு ஆராய்ச்சிக்காக அனுப்பப்பட்டுள்ள ரோவர் விண்கலமானது அங்கிருந்து பாறைகளின் மாதிரிகளை சேகரித்து கடந்த மாதம் பூமிக்கு அனுப்பியது.

பாறைகளின் மாதிரிகளை ஆராய்ச்சி செய்ததில் உயிர் வாழ்வதற்கு அடிப்படை வேதிப் பொருட்களான சல்ஃபர், நைட்ரஜன், ஹைட்ரஜன், ஆக்ஸிஜன், கார்பன் உள்ளிட்டவைகள் இருப்பது கண்டறியப்பட்டுள்ளது.

மேலும் பாறைகளின் மாதிரிகள் சேகரிக்கப்பட்ட இடத்தில் முன்னதாக நதியோ அல்லது ஏரியோ இருந்ததும் ஆராய்ச்சியில் தெரியவந்துள்ளது. இதனை தொடர்ந்து செவ்வாய் கிரகத்தில் முன்னொரு காலத்தில் உயிரினங்கள் வாழ்ந்ததற்கான வாய்ப்புகள் இருப்பதாக விஞ்ஞானிகள் தெரிவித்துள்ளனர்.

enga... vilunda...adipadathu...theriyuma...
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therilaya
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photola...vilunda.....ha.ha.ha