Computer Model Predicts Outbreaks of Ethnic Violence
Ethnic and sectarian violence that has plagued parts of Africa and Iraq in recent years can be predicted by using a model that examines the boundaries between different ethnic groups, a new study says.
While oppression of minorities, religious or political differences, and historical conflicts can be some of the triggers that motivate this type of violence, it is the structure of the boundaries that separate groups that enables communal violence, says study team member Yaneer Bar-Yam of the New England Complex Systems Institute.
If different ethic groups are very well-mixed in a community, violence is less likely to occur; if boundaries between groups are clearly defined, violence is unlikely to occur. But when the boundaries blur, and the amount of mixing is "just right," the situation can become explosive.
"That's the case that tends to promote violence," Bar-Yam said.
Islands and peninsulas
In the case of some well-mixed communities, it becomes harder for any one group to establish a collective identity or identify any one space in the community as belonging to them, and so no one group can dominate any others. Public housing in Singapore actually uses this principle to prevent sectarian violence by requiring a certain population mix, Bar-Yam said.
"There's tension there; there are historical events, but there's no major violence," he told LiveScience.
Conversely, groups that are separated by fairly rigid boundaries may have some antagonism between them, be it from religious differences or historical conflict, but the boundary prevents mixing, which minimizes the risk of violence breaking out.
In places like Ireland, "you have groups that sit side-by-side; there's plenty of historical events that might cause violence, and there's no violence," Bar-Yam said.
But where there is not significant mixing or boundaries to separate groups, people will tend to move to areas where there are people like them. This natural behavior can create "islands" of one population within another population or "peninsulas" that stick out from boundaries into other populations--the blurred boundaries between groups in these cases can create situations that allow violence to erupt. The group surrounding an island may impose their cultural norms on the group inside the island, which was the case in the former Yugoslavia.
"If people are in circumstances where their cultural behavior is being imposed or imposed upon, then they may very well find reasons to have conflict," Bar-Yam said.
Predicting violence
The model developed by Bar-Yam and his colleagues starts with the characteristics of the population (or the number of people in each grouping) and identifies the locations of population islands and peninsulas of particular sizes and marks the borders of these groups with other populations as a prime area for outbreaks of violence.
To check how well their model predicted the locations of outbreaks, the researchers took population data from the former Yugoslavia and India and checked the model's predictions against the locations of actual conflicts during the Bosnian War and in recent years in India.
The model's results correlated well with the places outbreaks actually occurred, with a 90 percent match between prediction and reality.
The model works independently of the particulars of the conflict, so it does not matter who is the aggressor, Bar-Yam says, also pointing out that the model makes no value judgments.
"The specifics of the group are not what's important," Bar-Yam said. "[The model] doesn't say, 'These people are right and these people are wrong'."
Bar-Yam says that the model could be used now in places such as Iraq to predict where outbreaks of violence will occur, and could be used by governments to formulate policies to prevent any outbreaks.
"Ethnic violence is really a horrendous thing, and to be able to provide information that can help prevent ethnic violence is really, obviously important," Bar-Yam said. "And having scientific tools that can contribute to the dialogue about what should be done is not only important but it is in some sense an imperative."
Fuel's gold: Termites point way to new dawn of bio-energy
A team of US scientists poring over the intestines of a tropical termite have a gut feeling that a breakthrough in the quest for cleaner, renewable petrol is in store.
Tucked in the termite's nether regions, they say, is a treasure trove of enzymes that could make next-generation biofuels, replacing fossil fuels that are dirty, pricey or laden with geopolitical risk.
Termites are typically a curse, inflicting billions of dollars in damage each year by munching through household timber with silent, relentless ease.
But gene researchers say the hind gut of a species of Central American termite "harbour a potential gold mine" of microbes which exude enzymes to smoothly break down woody fibres and provide the insect with its nutrition.
Present-generation biofuels are derived from corn, sugar and other crops, whose starch is converted into ethanol by enzymes, fermentation and distillation.
One of the problems, though, is that this product entails converting food into fuel. Hefty US subsidies to promote bio-ethanol is having price repercussions across swathes of the global food market.
Next-generation biofuels, though, would use non-food cellulose materials, such as wood chips and straw. But these novel processes, hampered by costs and complications, are struggling to reach a commercial scale.
The termite's tummy, though, could make all the difference.
Like cows, termites have a series of intestinal compartments that each nurture a distinct community of microbes.
Each compartment does a different job in the process to convert woody polymers into the kind of sugars that can then be fermented into biofuel.
The US team has now sequenced and analyzed the genetic code of some of these microbes in a key step towards -- hopefully -- reproducing the termite's miniature bioreactor on an industrial scale.
Their work, published on Wednesday in Nature, required scientists to venture into the rainforests of Costa Rica, where they plucked bulbous-headed worker termites from a large nest at the foot of a tree.
Using fine forceps and needles, they extracted the contents of the third paunch, or hind gut, from 165 termites, and sent this to a lab in California for sequencing.
From this, some 71 million "letters" of genetic code emerged, pointing to two major bacterial lineages called fibrobacters, which degrade cellulose, and treponemes, which convert the result to fermentable sugars.
Termite guts are incredibly efficient, said Andreas Brune of the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany.
"In theory, they could transform an A4-sized sheet of paper into two liters (1.8 pints) of hydrogen," he said.
Eddy Rubin, director of the Joint Genome Institute (JGI), an organisation that comes under the aegis of the US Department of Energy, said an important fundamental step had been made, even if a long road still lay ahead.
"Scaling up this process so that biomass factories can produce biofuels more efficiently and economically is another story," said Rubin.
"To get there, we must define the set of genes with key functional attributes for the breakdown of cellulose and this study represents an essential step along that path."
A coiled giant millipede rests on a log in the Budapest Zoo and Botanic Garden, July 2007. A team of US scientists poring over the intestines of a tropical termite have a gut feeling that a breakthrough in the quest for cleaner, renewable petrol is in store.
A wind farm near Malmo, Sweden. The use of wind power in many European countries has stagnated in recent years.
Sweden turns to a promising, but flawed, power source
Steadying himself on the heaving foredeck of an inspection ship recently, his face flecked by spray, Arne Floderus pronounced it a good day for his new offshore wind farm.
A 30-mile-an-hour wind was twirling the fingerlike blades of a turbine 380 feet above his head. Around him, a field of turbines rotated in a synchronized ballet that, when fully connected to an electrical grid, would generate enough power to light 60,000 nearby houses.
"We've created a new landmark," said Floderus, the project manager of the $280 million wind park, one of the world's largest, which was built by the Swedish power company Vattenfall.
The park, in a shallow sound between Sweden and Denmark, testifies to the remarkable rise of wind energy — no longer a quirky alternative favored by environmentalists in Denmark and Germany, but a mainstream power source used in 26 nations, including the United States.
Yet Sweden's gleaming wind park is entering service at a time when wind energy is coming under sharper scrutiny, not just from hostile neighbors, who complain that the towers are a blot on the landscape, but from energy experts who question its reliability as a source of power.
For starters, the wind does not blow all the time. When it does, it does not necessarily do so during periods of high demand for electricity. That makes wind a shaky replacement for more dependable, if polluting, energy sources like oil, coal and natural gas. Moreover, to capture the best breezes, wind farms are often built far from where the demand for electricity is highest. The power they generate must then be carried over long distances on high-voltage lines, which in Germany and other countries are strained and prone to breakdowns.
In the United States, one of the areas most suited for wind turbines is the central part of the country, stretching from Texas through the northern Great Plains — far from the coastal population centers that need the most electricity.
In Denmark, which pioneered wind energy in Europe, construction of wind farms has stagnated in recent years. The Danes export much of their wind-generated electricity to Norway and Sweden because it comes in unpredictable surges that often outstrip demand.
In 2003, Ireland put a moratorium on connecting wind farms to its electricity grid because of the strains that power surges were putting on the network; it has since begun connecting them again.
In the United States, proposals to build large wind parks in the Atlantic off Long Island and off Cape Cod, Massachusetts, have run into stiff opposition from local residents on aesthetic grounds.
As wind energy has matured as an industry, its image has changed — from a clean, even elegant, alternative to fossil fuels to a renewable energy source with advantages and drawbacks, like any other.
"The environmental benefits of wind are not as great as its champions claim," said Euan Blauvelt, research director of ABS Energy Research, an independent market research firm in London. "You've still got to have backup sources of power, like coal-fired plants."
Blauvelt publishes an annual report on wind energy in which he discusses its flaws. People in the industry would accuse him of propagating myths, he said. Now, the criticism is more tempered.
"One of the big problems with wind is that people tend to get hyped up about it, very emotional," Blauvelt said. "The difference is that the arguments are becoming more rational."
None of this is to say that wind power has peaked. On the contrary, Blauvelt figures the industry is adding capacity at a five-year compound annual growth rate of 26.3 percent. That is faster than hydroelectric power in its early days and twice the recent growth rate of nuclear energy.
The United States, which is considered a pioneer in wind, added more generating capacity in 2006 than any year on record. With 11,575 megawatts, the United States is the world's third largest wind country, after Germany and Spain, and it is adding more capacity than any other.
Among new countries with significant wind capacity are Britain, Canada, Italy, Japan and the Netherlands.
"What we're seeing is a second wave of countries, which are starting to invest more heavily," said Christian Kjaer, the chief executive of the European Wind Energy Association in Brussels.
He said wind energy would benefit from two parallel trends: rising oil prices and a global push to tax carbon-dioxide emissions. "It's very good way of hedging against volatile oil prices and potentially volatile carbon costs," Kjaer said.
In Germany, where 20,000 wind turbines generate 5 percent of the electricity, advocates say wind will be critical to meeting the government's goal of generating at least 20 percent of all power from renewable methods by 2020. But the industry's growth is slowing for a variety of reasons.
Germany is running out of places to put the turbines because of restrictions on the location and height of the devices. And rising raw material prices are making wind farms more expensive to build.
"Under the current circumstances, Germany's climate protection targets are not achievable," said Hermann Albers, the president of the German Wind Energy Association.
Open land is not a problem in the United States, but wind parks have faced resistance, particularly in scenic locales near the shore. A private developer, Cape Wind, wants to erect 130 turbines in Nantucket Sound, off Cape Cod. It has drawn protests from some well-connected locals, including the Kennedy family.
Cape Wind said it hoped to obtain all the necessary permits by next year, which would enable it to be up and running by 2011. "It's been a long road," said Mark Rodgers, a spokesman for the developer.
For a socially conscious society like Sweden, wind turbines exert a fashionable appeal.
Today, they account for less than 1 percent of Sweden's electricity generation. But the government wants to increase annual wind power production to 10 terawatt hours, or 10 trillion watt hours, by 2015 from less than 1 terawatt hour now (the park off Malmo will produce a third of a terawatt hour).
Vattenfall hopes to develop an even larger off-shore park in the Baltic Sea, between Sweden and Germany. In all, the government has identified 49 sites that are suitable for wind parks.
Sweden has historically invested little in wind projects because it has two reliable sources of energy, nuclear and hydro, which each supply roughly half its power. And because hydro is renewable, Sweden already does well on the environmental balance sheet.
But these energy sources have their vulnerabilities: hydro, to low water levels; nuclear, to technical breakdowns. The Swedish government has also pledged not to build any new nuclear power plants.
"One of the key energy priorities for Sweden is to establish a third leg of energy production," said Anders Nyberg, political adviser in the Ministry of Enterprise, Energy and Communications.
Of course, Sweden does not need to build wind parks to get wind power. It could simply buy more surplus wind power from Denmark, which it uses, as does Norway, to pump underground water into elevated reservoirs. The water is later released during periods of peak electric demand to drive hydroelectric stations.
In this way, hydro acts as a form of storage for wind energy — addressing one of wind power's biggest shortcomings. Sweden's strength in hydro makes it a good candidate for greater development of wind power, according to analysts.
Sweden is subsidizing wind power through "green" certificates, which favor the use of renewable energy. The small extra cost is passed on to consumers.
While Swedes staunchly support wind energy, they are as susceptible to the not-in-my-backyard opposition as people elsewhere. For years, residents opposed the wind farm near Malmo, known as Lillgrund, particularly after the builders obtained permission to raise the height of the towers. But the campaign to block the project failed.
Still, Floderus said the process took far too long, and Vattenfall is urging the government to speed up the approvals next time.
As his inspection ship followed a zigzag course through a field of 48 turbines, Floderus pointed to Malmo's two other landmarks, visible in the distance: Oresund Bridge, a 10-mile engineering marvel that connects Malmo with Copenhagen, and the Turning Torso, an eye-popping 54-story skyscraper designed by the Spanish architect Santiago Calatrava.
Soon, Floderus said, the whirling blades of the Lillgrund wind turbines would take their place alongside those landmarks as symbols of the modern age.
Eight unusual examples of a burned-out celestial object known as a white dwarf detected in our Milky Way galaxy represent a previously unknown category of stars, astronomers said on Wednesday.
White dwarfs mark the end point in stellar evolution for all but the most massive of stars in the universe, with about 97 percent of stars, including our sun, destined to finish their existence this way, according to astronomers.
White dwarfs result from the collapse of star cores in dying stars whose nuclear fusion has ceased. They usually have a mass about that of the sun, but are only a bit larger than Earth because they have blown off their outer layers, leaving behind only a small, dim and extremely dense core.
University of Arizona astrophysicist Patrick Dufour said previously known white dwarfs have fallen into two categories: those with a hydrogen-rich atmosphere and those with a helium-rich atmosphere. But Dufour and three other scientists, writing in the journal Nature, described eight white dwarfs that break the mold by possessing carbon atmospheres.
The researchers think they may have formed from stars much more massive than the sun but not quite massive enough to explode as a supernova.
"It was totally unexpected because all of the white dwarfs we knew so far were either hydrogen-rich or helium-rich. So this is a completely new kind of star," Dufour said in a telephone interview.
These eight white dwarfs are located in our own galaxy between about 1,000 and 2,000 light years from Earth, Dufour said. A light year is about 6 trillion miles, the distance light travels in a year.
The scientists have spotted at least a couple of other white dwarfs that might fit into this new category, Dufour added. All of them were among about 10,000 new white dwarfs recently identified in an extensive survey effort.
After blowing off their outer layers, white dwarfs typically leave behind a core of carbon and oxygen that is cloaked by a surrounding atmosphere of hydrogen or helium. The eight newly described ones have atmospheres primarily of carbon, with little or no trace of hydrogen or helium.
"It will be a challenge to try to explain how they form and what does this tell us about stellar evolution," Dufour said.
They might have evolved from a star similar to a unique one called H1504+65, the researchers said. Astronomers think this star violently expelled all its hydrogen and nearly all its helium, leaving behind a stellar nucleus with a surface half carbon and half oxygen.
An artists' concept of the surface of the white dwarf star H1504+65, released to Reuters on November 21, 2007. Eight unusual examples of a burned-out celestial object known as a white dwarf detected in our Milky Way galaxy.
TWENTY FOUR SATELLITES make up the Global Positioning System. NASA
The Global Positioning System (GPS) consists of 24 operating satellites and several spares. Some of these spare satellites are also in use or can readily be activated once an operating satellite becomes dysfunctional. Taking the specific orbits of this many satellites into consideration, an observer can see at least four satellites at any time from any location on the earth.
Methods to use GPS are more or less complicated depending on the desired accuracy and speed of positioning. For a simple example, assume that the orbital positions of the satellites can be accurately computed with respect to the earth at any time. Further assume that a GPS receiver on the ground can measure the distance between a receiver and a satellite for at least three satellites at the same time. By defining the receiver location with three coordinates, such as latitude, longitude and height, one can readily write three equations that relate the three distance observations to the known coordinates of the satellites and the unknown coordinates of the receiver. These three equations can be solved for the three unknowns.
The distance to the satellites is measured by timing signals transmitted by the satellites that travel with the speed of light toward a receiver on the ground. Because of the high speed of light, it is necessary that the instant of signal transmission at the satellite and the instant of signal reception at the receiver?s antenna be accurately registered in order for the distance and, consequently, the position calculation to be accurate. Satellites in fact carry atomic clocks. Receivers, in contrast, contain inexpensive and therefore less accurate clocks. As a result, we must allow for a timing error to occur as the arriving satellite signal is timed at the receiver. Because the signals arriving at a receiver from all satellites are measured at the same time, the distance measurements are all falsified by the same receiver clock error, which must be calculated in order to determine an accurate position. The complete position determination of the receiver consequently requires four unknowns: the receiver clock error and the three receiver coordinates. Measuring distances to at least four satellites allows one to set up four equations that can be solved for these four unknowns. This leads to the fundamental requirement for a truly global positioning system that at least four satellites be visible at any time from any location on the earth. In practice, receivers observe all visible satellites to determine the best estimates of both the receiver clock and location.
The solution described above is usually called the navigation solution. This type of calculation is implemented in virtually all receivers, including inexpensive handheld devices. In addition to determining position, the time is available to an accuracy of better than one microsecond. GPS receivers are therefore very valuable for time synchronization between remotely located clocks. Time synchronization is an important element in modern communication by Internet, telephone, TV broadcast and many other means.
A closer look at the underlying theories and techniques readily reveals that GPS positioning is not at all simple. This may be of little interest to hikers and motorists who use GPS to get from here to there. But for scientists, GPS is a utility with an endless list of applications, ranging from ionospheric and tropospheric studies to earth crust deformations. The list is equally long for engineering applications. GPS has truly become a national utility.
