Tag Archives: science

The Manaus Meeting of Waters

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We had heard about the merging of the Rio Negro,a river with dark(almost black colored ) water and the sandy-colored AmazonRiver(Rio Solimoes) just outside of Manaus but nothing could have prepared me for the sight of it from a sea plane that we took from our lodge on the Rio Negro, to Manaus.

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For  3.7 miles ,the river’s waters run side by side without mixing .This phenomenon is due to the differences in temperature, speed and water density of the two rivers. The Rio Negro flows at near 1.1 miles per hour at a temperature of  82.4 degrees(28°c), while the Rio Solimões flows between  2-3 miles per hour a temperature of 71.6 degrees(22 c).

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We also noticed that there are a lot of places where the convergence is depicted with tile work. This is at the Opera House in Manaus.

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Thank Heaven for GPS!

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If there was ever a justification needed for space technology, it’s that it keeps people like me from constantly being lost. These days, my car GPS and iphone are much better than me at getting around thanks to a fleet of satellites that tells them where they are at all times.

Though not a particularly romantic anniversary, last month marks 25 years since the first satellite in the U.S. Global Positioning System launched from Cape Canaveral, beginning the set up for one of the wonders of the modern world. In the two and a half decades since then, GPS has become inextricably embedded into just about everything we own, finding use in cartography, smart phone apps, geotagging and geocaching, disaster relief, and hundreds of other applications, while simultaneously raising privacy concerns.

GPS relies on at least 24 satellites flying 20,000 kilometers overhead in one of six different orbital paths, tracing out what looks like a toy model of an atom. With their solar panels extended, each of these 1-ton satellites is about the same size as a giraffe. At any given moment, each satellite beams out a signal identifying itself and giving its time and location.

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A model showing the 24 original GPS satellites in orbit and a point on the Earth rotating. Animation: El pak/Wikimedia

Your GPS-enabled phone or car captures that signal and compares the time it was received to the time it was transmitted. A quick calculation involving the speed of light allows the device to figure out the distance to that satellite. If you have your distance to two or three satellites, you can triangulate your position on the Earth. When all the GPS satellites are working, a user always has at least four in view, allowing them to determine things like altitude, speed, and direction.

In September of 1973, the top brass met at the Pentagon and came up with what would eventually become known as the Navigation System Using Timing and Ranging program, called Navstar-GPS, which was later shortened to just GPS. Between 1978 and 1985, the military launched 11 satellites (10 of which worked) to test the new GPS system.

After Korean Air Lines  flight 007 was shot down in 1983 for wandering into prohibited U.S.S.R. airspace, President Reagan promised that GPS would be opened up for civilian use on passenger aircraft once it was completed. The first GPS satellite in the modern fleet launched on Feb. 14, 1989. The Air Force had planned to use the space shuttle for this launch in 1986 but was delayed by the Challenger disaster and eventually used a Delta II rocket. The full GPS fleet was completed in 1994 and now at least 32 satellites are in orbit to provide redundancy. During the same time, the Russians developed and launched GLONASS, which works on principles similar to GPS, and is currently the only alternative location-finding system in the world.

At its beginning, the U.S. military feared that GPS technology would be used by enemies, and purposely degraded civilian information so that it could only provide accurate location information to within 100 meters. In 2000, President Clinton had this feature turned off and now civilian devices are usually accurate to within 5 to 10 meters. The European Union and China are currently building their own global navigation systems, known as Galileo and Beidou, respectively, that will serve as further alternatives to GPS in the coming decade. It seems likely that folks in the future will never have to worry about being lost again.

excerpts from Wikepedia and Adam Mann in Map Lab article

By The Light Of The Candle

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Candlelit dinners really could be good for the heart, new Swedish research has suggested

Candlelit dinners really could be good for the heart, new Swedish research has suggested.

A candlelit dinner works wonders for romance.Now scientists say it could also be good for your heart.Breathing in candle smoke causes beneficial changes in cardiac rhythm, they claim.It is thought that tiny salt particles released when the candle burns are behind  the effect.

The researchers monitored the hearts of 13 men and women as they breathed in air pumped into a small chamber. In some cases the air included smoke from candles in a second room.The volunteers didn’t know which type of air they were breathing, but when it included candle smoke, their heart rate variability improved.Everyone’s heart rate varies naturally all the time, beating a little bit faster when we breathe in than when we breathe out.

This is perfectly healthy and a sign that the brain is alert and able to regulate the heart. But this variation falls as we get older and if we develop heart problems. In the study, it was increased by inhaling candle smoke.

Researcher Christina Isaxon from Lund University in Sweden said the concentration of smoke generated during the study was similar to that created by a candlelit dinner.

As the volunteers could not see the candles and weren’t told what they were breathing, the effect could not be explained away by the calming effect of candlelight .Dr Isaxon said she thought tiny particles of sodium and potassium, which along with soot, make up candle smoke, could be responsible for the  beneficial effects.The two elements are involved in regulating the heart’s rhythm and in sending messages between cells in the body.More salts are produced when a flame is still so she recommends that candles are burned away from drafts. Breathing in candle smoke causes beneficial changes in cardiac rhythm, the study found.

The study, carried out for her PhD, did not find any negative health effects of the smoke – although Dr Isaxon admitted said she did not ‘make a huge effort’ to find any.Soot, which increases when the flame flickers, has been blamed for health problems in the past.The American Chemical Society has warned that paraffin wax candles, the most common type, release potentially harmful chemicals linked to cancer, asthma and eczema. It recommends using beeswax and soy candles.Dr Isaxon used candles made of pure stearine, a natural fat, in her study. Many other types of candle also contain some stearine. Dr Isaxon found paraffin wax candles which had stearine in them also released potassium and sodium particles.

Stearine candles were first developed 200 years ago.They are very popular in Scandinavia and can be bought here from retailers including Ikea.Dr Isaxon recommended using candles that are as natural as possible and avoiding scents and dyes as they may give off dangerous chemicals when burned.Since we spend more than 85 per cent of our time indoors, what we breathe in at home is very important, she said.

from Mail Online February 28,2014