Science & Technology

Millions face famine as crop disease rages

Scientists say wheat blight that ravaged Africa is set on a course for Asia :

Robin McKie and Xan Rice

Crop disease: Millions of people face starvation following an outbreak of a deadly new strain of crop disease which is spreading across the wheat fields of Africa and Asia, say scientists.

The disease, known as black stem rust, has already destroyed harvests in Uganda, Kenya, and Ethiopia. Now researchers report that stem rust spores have blown across the Red Sea into the Arabian peninsula and infected wheat fields in Yemen. Spores have also blown northwards into Sudan.

Experts believe the disease - Puccinia graminis - will spread to Egypt, Turkey, the Middle East, and finally India and Pakistan, which would lead to the destruction of the principal source of food for more than a billion people. Some observers warn that the disease could reach Egypt, which is heavily dependent on wheat, before the end of this year.

"This thing has immense potential for social and human destruction," the international agriculture expert and Nobel prize-winner Norman Borlaug warned this month.

Black stem rust has blighted wheat production in many parts of the world for thousands of years. So pernicious were its effects that the Romans prayed to a stem rust god called Robigus.

"The Bible talks about plagues afflicting crops and these are almost certainly references to stem rust," said Rick Ward, of the Global Rust Initiative, which has been set up to counter the new threat.

When an outbreak occurred, a field of ripening wheat would be transformed into a mass of blackened vegetation. Every few years one of these outbreaks would lay waste to entire harvests, sometimes sweeping across continents in only a few months.

But in the 1960s scientists and agriculture experts began to develop ways to counter the menace. Disease-resistant varieties of wheat were produced and planted in the West and in developing countries. As a result, it disappeared from most farms.

"Stem rust was something we felt we had solved," Mariam Kinyua, a plant breeder at the Kenya Agricultural Research Institute in Njoro, told the journal Science this month.

However, a new strain of the fungus - known as Ug99 - was found in breeding nurseries in Uganda several years ago.

The discovery caused alarm because virtually every variety of wheat tested with the strain was severely affected. "Varieties that had been resistant for many years were no longer resistant," said Wafa Khoury, a plant pathologist at the United Nations Food and Agriculture Organisation in Rome.

Within a year Ug99 was found in fields in Kenya and Uganda.

The damage inflicted was severe but did not cause huge social problems because wheat is not a staple crop in either country.

Nevertheless a field centre for Ug99 was established in Njoro and samples of wheat from around the world, including Argentina, Canada and Australia, were sent for testing.

Virtually every single sample was found to be susceptible. "That's what really caused the panic," said Mr. Khoury.

This point was backed by Mr. Ward. "The world had been safe for 50 years, but now the biblical plague that used to afflict our crops has returned. This is a very serious situation."

The chilling feature about the new stem rust strain is the manner of its attack: Ug99 specifically targets resistance genes in wheat. As a result, it is now believed that 80 per cent of wheat varieties grown in the developing world are likely to be susceptible to the fungus. "It's heaven for the [Ug99] pathogens," said Mr. Khoury.

The spread of Ug99 to Yemen, where wheat is a staple, was confirmed in February by a team that included Mr. Khoury. Now studies of wind patterns suggest Ug99 will soon spread to Saudi Arabia and the Near East. Eventually Syria, Lebanon, Turkey, Iran, Pakistan, and Europe could be affected.

"We have to breed new wheat strains that are resistant to Ug99," said Mr. Ward.

"If we do not, then we face the prospect of countries like Egypt and Pakistan suffering calamitous losses of wheat production.

That would trigger all sorts of destabilising effects, ones that could have profound implications for the West. We have to move quickly. There is no time to lose." -

Courtesy Guardian

Sun 3-D pictures help warn of solar flares

IMAGES: The first three-dimensional images of the Sun from a pair of spacecraft orbiting the planet were released on Monday and can begin helping scientists predict when and how hard dangerous solar storms will hit, the U.S. space agency NASA said.

Such storms can disrupt satellites, communications and sometimes the electricity supply, and may endanger astronauts in Earth orbit as well as commercial airline flights.

The twin Solar Terrestrial Relations Observatory, or STEREO, satellites can create more accurate, real-time views of these storms, called coronal mass ejections, project scientists said.

"The improvement with STEREO's 3-D view is like going from a regular X-ray to a 3-D CAT scan in the medical field," said Michael Kaiser, STEREO Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The STEREO spacecraft were launched in October and have now been maneuvered into their orbits, one slightly ahead of Earth and one slightly behind.

"Just as the slight offset between a person's eyes provides depth perception, the separation of spacecraft allow 3-D images of the sun," NASA said in a statement.

Solar storms are a conglomeration of charged gases and magnetic forces. When they hit the Earth's magnetic barrier they cause the auroras, the dramatic Northern and Southern lights.

But they can also disrupt satellites, radio communication, and power grids. The radiation they carry is a danger to astronauts.

The orbiting SOHO observatory is providing some information, but the two STEREO spacecraft will be able to triangulate with SOHO and give a much better view of these bursts as they bud off the sun's surface, NASA said.

"In the solar atmosphere, there are no clues to help us judge distance. Everything appears flat in the 2-D plane of the sky. Having a stereo perspective just makes it so much easier," said Russell Howard of the Naval Research Laboratory.

"Knowing where the front of the coronal mass ejection cloud is will improve estimates of the arrival time from within a day or so to just a few hours," Howard added.

"STEREO also will help forecasters estimate how severe the resulting magnetic storm will be."

Reuters

NASA nebula image captures violent birth of stars

Will Dunham

SPACE: A dazzlingly detailed image released by NASA scientists shows the chaotic conditions in which stars are born and die - in this case in a huge nebula in another neighborhood of our Milky Way galaxy.

The image, made from a series of 48 shots taken by the orbiting Hubble Space Telescope in spring and summer of 2005, depicts star birth in a new level of detail.

It provides a view spanning a distance of 50 light years across of the Carina Nebula. A nebula is an immense cloud of hot interstellar gas and dust.

This messy and chaotic region includes at least a dozen brilliant stars estimated to be perhaps 50 to 100 times the mass of the sun, astronomers said.

One of them, called Eta Carinae, is in the final stages of its short life span, with two billowing lobes of gas and dust a harbinger of its future explosion as a large supernova.

"In short, it gives us a glimpse of the violent conditions that most stars are born in, where they are exposed to the relentless irradiation from their older siblings," astronomer Nathan Smith of the University of California at Berkeley, the lead investigator in this work, said by e-mail.

"There are several clues suggesting that our sun and planets were indeed born in a violent region something like this, along with some very hot and massive stars," Smith added.

Our solar system was formed about 4.6 billion years ago. The nebula is about 7,500 light years away from Earth in the constellation Carina in a neighboring spiral arm of our Milky Way galaxy. The Hubble image depicts a massive region, but it is only a small portion of the whole nebula, which spans 150 to 200 light years across, Smith said.

People can see the nebula with the naked eye from Earth's southern hemisphere, Smith said.

Reuters

Scientists crack beer-froth enigma

BUBBLES: There is the nagging question of whether life exists other than on Earth. The enduring mystery of who made us - and why.

And then there is this: Why does the foam on a pint of lager quickly disappear but the head on a pint of Guinness linger?

Answers to questions 1 and 2 are still being sought, but the Great Beer Riddle, at least, may soon be solved.

Writing in the prestigious British science journal Nature, an elite scientific duo say they have devised an equation to describe beer froth.

The breakthrough will not only settle the vexatious lager vs. stout debate, it will also help the quest to pour a perfect pint every time.

Beer foam is a microstructure with complex interfaces. In other words: a cellular structure comprising networks of gas-filled bubbles separated by liquid.

The walls of these bubbles move as a result of surface tension - and the speed at which they move is related to the curvature of the bubbles. As a result of this movement, the bubbles merge and the structure "coarsens," meaning that the foam settles and eventually disappears.

Three-dimensional equations to calculate the movement have been made by Robert MacPherson, a mathematician at the Institute for Advanced Study in Princeton, New Jersey, and David Srolovitz, a physicist at Yeshiva University, New York.

They build on work by a computer pioneer, John von Neumann, who in 1952 devised an equation in two dimensions.

The mathematics of beer-bubble behaviour are similar to the granular structure in metals and ceramics, so the equation also has an outlet in metallurgy and manufacturing as well as in pubs.

AFP

Mystery fossil turns out to be giant fungus

FUNGUS: Scientists have identified the Godzilla of fungi, a giant, prehistoric fossil that has evaded classification for more than a century, U.S. researchers said on Monday.

A chemical analysis has shown that the 20-foot-tall (6-metre) organism with a tree-like trunk was a fungus that became extinct more than 350 million years ago, according to a study appearing in the May issue of the journal Geology.

Known as Prototaxites, the giant fungus originally was thought to be a conifer. Then some believed it was a lichen, or various types of algae. Some suspected it was a fungus.

"A 20-foot-fungus doesn't make any sense. Neither does a 20-foot-tall algae make any sense, but here's the fossil," C. Kevin Boyce, a University of Chicago assistant professor of geophysical sciences, said in a statement.

Francis Hueber of the National Museum of Natural History first suggested the fungus possibility based on an analysis of the fossil's internal structure, but had no conclusive proof.

Boyce and colleagues filled in the blanks, comparing the types of carbon found in the giant fossil with plants that lived about the same time, about 400 million years ago. If Prototaxites were a plant, its carbon structures would resemble similar plants.

Instead, Boyce found a much greater diversity in carbon content than would have been expected of a plant. Fungi, which include yeast, mold and mushrooms, represent their own kingdom, neither plant nor animal. Once classified as plants, they are now considered a closer cousin to animals but they absorb rather than eat their food.

Samples of the giant fungi have been found all over the world from 420 million to 350 million years ago during a period in which millipedes, bugs and worms were among the first creatures to make their home on dry land. No animals with a backbone had left the oceans yet.

The tallest trees stood no more than a couple of feet (a metre) high, offering little competition for the towering fungi.

Plant-eating dinosaurs had not yet evolved to trample Prototaxites' to the ground. "It's hard to imagine these things surviving in the modern world," Boyce said.

Reuters

Earth II: Is there life out there?

PLANET: Above a calm, dark ocean, a huge, bloated red sun rises in the sky a full 10 times the size of our Sun as seen from Earth. Small waves lap at a sandy shore and on the beach, something stirs...

This is the scene or may be the scene on what is possibly the most extraordinary world to have been discovered by astronomers: the first truly Earth-like planet to have been found outside our Solar System.

A team of European astronomers announced that the discovery of the potentially habitable planet, with Earth-like temperatures, is a big step in the search for "life in the universe".

The planet is just the right size, might have water in liquid form, and in galactic terms is relatively nearby at 190 trillion km, or 20.5 light years, away. But the star it closely orbits, known as a "red dwarf", is much smaller, dimmer and cooler than our sun.

There's still a lot that is unknown about the new planet, which could be deemed inhospitable to life once more is known about it. And it's worth noting that scientists' requirements for habitability count Mars in that category: a size relatively similar to Earth's with temperatures that would permit liquid water. However, this is the first planet outside our solar system that meets those standards.

"It's a significant step on the way to finding life in the universe," said University of Geneva astronomer Michel Mayor, one of 11 European scientists on the team that found the planet.

"I expect there will be planets like Earth, but whether they have life is another question," said renowned astrophysicist Stephen Hawking. "We haven't been visited by little green men yet."

The results of the discovery have not been published but have been submitted to the journal Astronomy and Astrophysics.

The planet was discovered by the European Southern Observatory's telescope in La Silla, Chile.

It circles the red dwarf star, Gliese 581. Red dwarfs are low-energy, tiny stars that give off dim red light and last longer than stars like our sun. Agencies.

Times of India