|SCIENCE TRIBUNE||Thursday, September 19, 2002, Chandigarh, India|
SEPTEMBER 16 WAS
aids continued medical education; IMA shows how
life and death of stars
Though we cannot examine the stars, in laboratory-tested laws are well applicable on these distant objects. Based upon these laws, scientists have developed mathematical models of stellar evolution. These models can be run as numerical simulations on computers and their agreement with the observed facts is one of the major triumphs of the 20th century astrophysics. It must be clearly understood that the term "evolution" in case of stars refers to the life-cycle of a single star and thus, is entirely different from the Darwinian evolution, which always applies to a specie.
So far, we have seen how stars are born out of gas and dust and how they spend the major part of their life —fusing hydrogen into helium during their main sequence phase on the HR diagram. It might sound strange, but the nuclear energy actually keeps the star cooler than water what the gravitational collapse would otherwise have made of it. After the exhaustion of nuclear fuel in its core, the star once again begins to collapse under gravity and gets heated to much higher temperatures. The fate beyond this point depends upon its mass. A star weighing less than half our sun at this stage will end its life peacefully as a white dwarf. Similar to our earth in size a white dwarf is a close agglomeration of subatomic particles, which are supported by electrostatic repulsive forces against the crushing inward tug of gravity. A cubic centimeter of this matter weighs as much as a metric ton. A white dwarf continues to cool itself by radiating energy and eventually becomes a black dwarf.
Stars weighing from 0.5 to 2.25 times the sun generate so much heat during their collapse that fusion reactions of hydrogen start in regions surrounding the core. These thermonuclear reactions lead to expansion of the shell to some 50 times its original size. Expansion eventually cools these outer layers, making them look orange-red in colour. Such a star is known as a "Red Giant’. As the temperature of core rises to 100 million degrees, helium begins to fuse into carbon and oxygen through a rapid reaction, called "Helium Flash". The heat thus generated stops the collapse of core for around one million years. After exhaustion of helium in the core, the star undergoes a rapid contraction and releases so much heat that simultaneous hydrogen and helium fusion reactions get initiated further outside the core. The shell expands very rapidly, getting ejected in the form of a planetary, nebula while the remaining star ends as a white dwarf.
Those having good telescopes with them can enjoy the sights of many planetary nebulae in the night sky. M27 Dumbbell Nebula (Mag. 7.4) in Vulpecula, M57 Ring Nebula (Mag. 8.8) in Lyra and M97 Owl Nebula (Mag. Nebula 9.9) in Ursa Major are easy to find using a star-chart.
The star loses nearly one-third of its
total mass during this process - enriching the interstellar space with
heavy elements and sending out explosion waves, which act as seeds for
the formation of new stars. All elements heavier than hydrogen and
helium present in this universe were manufactured and scattered in this
manner. In fact, we would not have been sitting here, had some previous
generations of stars not enriched the interstellar medium with elements
like carbon, oxygen, nitrogen etc some billons of years ago, when the
solar system was yet to form. Everything on earth — including
ourselves, is a star-dust memory.
16 WAS OZONE DAY
The hole in the ozone layer over Antarctica may close within 50 years, as the level of destructive ozone-depleting CFCs in the atmosphere is now declining, one of the world’s leading atmospheric scientists has said.
Paul Fraser of the Australian government’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) said he had measured a decline in ozone-destroying gases since 2000.
‘’The major culprit in the production of the ozone hole is the CFCs and these have started to decline in the lower atmosphere,’’ Fraser said.
‘’We think the ozone hole will recover by about 2050,’’ said Fraser, a lead author of a UN report on the ozone layer.
The report said ozone-depleting gases in the upper atmosphere had been at or near the peak in 2000, but the world was making steady progress towards the recovery of the ozone layer.
It said levels of ozone-depleting gases in the lower atmosphere were ‘’declining, albeit slowly’’, but the ozone cover would be vulnerable for a decade.
The ozone layer is essential for life on the Earth, shielding it from the harmful ultraviolet-B radiation from the Sun and completely screening out lethal UV-C radiation.
Chlorine from chlorofluorocarbons (CFCs) is responsible for destroying part of the ozone layer over Antarctica. The CFCs have been widely used since the 1930s in refrigerator, and air-conditioners; and remain in the atmosphere for decades.
Under the 1987 Montreal Protocol, developing countries committed themselves to halving consumption and production of the CFCs by 2005 and to achieving an 85 percent cut by 2007.
Fraser, who monitors the CFCs from Australia’s southern island of Tasmania, said, in 1950 the atmospheric level of chlorine from the CFCs had been zero, risen, to a peak of 2.15 parts per million in 2000, but fallen at one per cent a year since 2000.
‘’We are, now, at a point where the atmosphere can actually remove the CFCs faster than they are being released into the atmosphere,’’ said Fraser. The actual decline in the CFCs had not been measured when the UN report was compiled in 2000. The UN report, the latest in a series of four-yearly reports reviewing the ozone layer since the Montreal Protocol, said the reduction in the CFCs proved the protocol was working.
The report also warned that the hole over Antarctica would only close fully if countries continued to adhere to the protocol and if other factors increase in greenhouse gases were removed. Reuters
Internet aids continued medical education; IMA shows how
With the Indian Medical Association (IMA) introducing its distance-education programme on the Internet, it would be possible for doctors to get updates and training in specialised fields at the touch of a finger, sitting at home even in the remotest village.
"Any doctor can join the courses offered by the IMA, if he or she has a computer and an Internet connection," Dr Sanjiv Malik, honorary secretary general of the IMA said. The examination would be conducted online and the results would be published immediately.
"To ensure success of the programme, the IMA has given a computer and an Internet connection free to each of its 30 state branches and asked the heads to ensure that local branches get it too", he said.
There are about two modules and more could be added to the programme as takers increased, he said.
The programme includes on torture medicine, paediatrics, HIV/AIDS adolescent health, geriatrics, environment and occupational hazard, psychiatry, TB and chest diseases, medical negligence and the Consumer Protection Act (CPA) etc.
"In India one cannot enter college
as a student after a certain age; therefore problem arises when a doctor wants
to update his knowledge," Dr Malik said. Continued Medical Education was,
therefore, important for doctors Dr Malik said: Not all doctors are able to
attend the CME seminars for various reasons. The IMA, therefore, thought that
it would be best if medical education could reach doctors instead. We found the
Internet to be important in this direction, as doctors could use it as a tool
for distance learning. This medium also ensured that maximum number of doctors
could be benefited. PTI
NEW PRODUCTS & DISCOVERIES
Smart clothing gets musical
German company Infineon has outlined plans for new high-tech textiles and demonstrated a washable "music jacket" prototype that lets the wearer play MP3 files.
The German semiconductor company has demonstrated a variety of prototypes for wearable microchips that can be sewn directly into clothing and other textiles. The company said that one possible application for the new fabrics is a prototype audio module which Infineon claims is already production-ready.
Infineon worked with the German Master School of Fashion in Munich to design various pieces of clothing that can play MP3s and that can be washed without the need to remove the electronics.
The MP3 jacket would comprised four units, including a microcontroller/sound processing chip, a removable battery and multimedia card (MMC) module, an earplug/microphone as well as a flexible sensor keyboard. All of the components are electrically interconnected through fabric strips with embedded conductors and the audio chip can directly be linked to microphones, earplugs, memories, keyboards, displays, sensors and actuators.
The division behind the new technology is Infineon’s Emerging Technologies Group. For now there seem to be no plans to put the new clothes into production but the company thinks that in time there will be uses for the new fabrics in the entertainment, communications, health care and security industries.
"True to our motto ‘Never stop thinking,’ our researchers have been addressing a subject that will be ubiquitous in a couple of years," said Dr Sonke Mehrgardt, chief technology officer at Infineon. "The further evolution of our information society will make everyday electronic applications ever more invisible and natural. The enabling technologies we presented today are a major step toward this objective."
Other applications in the works at Infineon include similar wearable chips used to monitor patients’ vital signs. The company says it hopes to incorporate wireless technology into the fabrics as well for remote monitoring and data transfer purposes. In the future, the company also envisions outfits that would use a person’s body heat to power the electronic devices in their clothes.
Cashing in on the ability of a pigment, Lycopene, found naturally in tomatoes to act as a cancer fighting agent, scientists in the USA have developed tomatoes that have three times more of this pigment.
The research by the scientists of the Purdue University and the US Department of Agriculture’s (USDA) Agricultural Research Service was aimed at developing higher quality tomatoes that would ripen late in view of food processing needs.
In the process scientists discovered that the new tomatoes also had more of the antioxidant Lycopene than their conventional counterparts, according to a US embassy release.
The research, published in the science journal "Nature Biotechnology" involved inserting a gene along with another gene (promoter), derived from yeast, into tomato plants.
The yeast gene produces an enzyme that affects the production of certain growth substances in the plants called polyamines help build new beneficial compounds. The promoter helps expression of yeast gene in fruits only.
"We are excited about this approach, not because
it results in an increase in Lycopene in tomato, but because we think
this approach could be used to increase the phytonutrient content of
other fruits and vegetables," Avtar Handa, Professor of
Horticulture at Purdue, said. PTI
SCIENCE & TECHNOLOGY CROSSWORD
1. Substances producing heat.
8. Oval, hard-stoned, oil yielding fruit.
9. A shell that fails to explode.
10. A high speed passenger train developed abroad and powered by linear electric motors.
11. Solid figure with every point on its surface equidistant from centre.
13. A fever following child-birth and caused by uterine infection.
14. Short for electric.
16. Strong metal commonly used in tools.
18. Rotating machine used in turnery for turning metals.
20. Abbr. for a chemical used in making repellant creams.
22. A popular name in welding rods.
23. This energy is produced by fusion or fission of atoms.
25. Surgical treatment to an afflicted part of body.
1. Substances made up of two or more elements combined chemically in a fixed ratio by weight.
2. Fertile deposits of soil left by floods.
3. Large glandular organ in body secreting bile.
4. Apparatus worn over mouth and nose to warm or filter inhaled air.
5. A scale of temperature on which water freezes at 32 degrees.
6. A gas obeying the gas laws very strictly.
7. Long billed wading bird.
12. Short for Public Enterprise.
15. Non metallic element occurring in all organic compounds.
17. Doctor’s lingo for ‘Operation Theatre’.
19. An engineering staff college of Institution of Engineers(India).
21. A programme launched by most countries and UN to control pollution by using sophisticated equipment.
24. Symbol for semi-metal Tellurium.
Solution to last week’s