venerdì 31 ottobre 2008

Acclaimed Colombian Institution Has 4,800 Books and 10 Legs

http://www.nytimes.com/2008/10/20/world/americas/20burro.html

LA GLORIA, Colombia — In a ritual repeated nearly every weekend for the past decade here in Colombia’s war-weary Caribbean hinterland, Luis Soriano gathered his two donkeys, Alfa and Beto, in front of his home on a recent Saturday afternoon.
Sweating already under the unforgiving sun, he strapped pouches with the word “Biblioburro” painted in blue letters to the donkeys’ backs and loaded them with an eclectic cargo of books destined for people living in the small villages beyond.
His choices included “Anaconda,” the animal fable by the Uruguayan writer Horacio Quiroga that evokes Kipling’s “Jungle Book”; some Time-Life picture books (on Scandinavia, Japan and the Antilles); and the Dictionary of the Royal Academy of the Spanish Language.
“I started out with 70 books, and now I have a collection of more than 4,800,” said Mr. Soriano, 36, a primary school teacher who lives in a small house here with his wife and three children, with books piled to the ceilings.
“This began as a necessity; then it became an obligation; and after that a custom,” he explained, squinting at the hills undulating into the horizon. “Now,” he said, “it is an institution.”
A whimsical riff on the bookmobile, Mr. Soriano’s Biblioburro is a small institution: one man and two donkeys. He created it out of the simple belief that the act of taking books to people who do not have them can somehow improve this impoverished region, and perhaps Colombia.
In doing so, Mr. Soriano has emerged as the best-known resident of La Gloria, a town that feels even farther removed from the rhythms of the wider world than is Aracataca, the inspiration for the setting of the epic “One Hundred Years of Solitude” by
Gabriel García Márquez, another of the region’s native sons.
Unlike Mr. García Márquez, who lives in Mexico City, Mr. Soriano has never traveled outside Colombia — but he remains dedicated to bringing its people a touch of the outside world. His project has won acclaim from the nation’s literacy specialists and is the subject of a new documentary by a Colombian filmmaker, Carlos Rendón Zipaguata.
The idea came to him, he said, after he witnessed as a young teacher the transformative power of reading among his pupils, who were born into conflict even more intense than when he was a child.
The violence by bandit groups was so bad when he was young that his parents sent him to live with his grandmother in the nearby city of Valledupar, near the Venezuelan border. He returned at age 16 with a high school degree and got a job teaching reading to schoolchildren.
By the time he was in his 20s, Colombia’s long internal war had drawn paramilitary bands to the lawless marshlands and hills surrounding La Gloria, leading to clashes with guerrillas and intimidation of the local population by both groups.
Into that violence, which has since ebbed, Mr. Soriano ventured with his donkeys, taking with him a few reading textbooks, encyclopedia volumes and novels from his small personal library. At stops along the way, children still await the teacher in groups, to hear him read from the books he brings before they can borrow them.
A breakthrough came several years ago when he heard excerpts over the radio of a novel, “The Ballad of Maria Abdala,” by Juan Gossaín, a Colombian journalist and writer. Mr. Soriano wrote a letter to the author, asking him to lend a copy of the book to the Biblioburro.
After Mr. Gossaín broadcast details of Mr. Soriano’s project on his radio program, book donations poured in from throughout Colombia. A local financial institution, Cajamag, provided some financing for the construction of a small library next to his home, but the project remains only half-finished for lack of funds.
There is little money left over for such luxuries on his teacher’s salary of $350 a month. Already the family’s budget is so tight that he and his wife, Diana, opened a small restaurant, La Cosa Política, two years ago to help make ends meet.
Even among the restaurant’s clientele, mainly ranch hands and truck drivers with little formal education, the bespectacled Mr. Soriano sees potential bibliophiles. On the wall above tables laid out with grilled meat and fried plantains, he posts pages from Hoy Diario, the region’s daily newspaper, and prods diners into discussions about current events.

“We can take political talk only so far, of course,” he said, referring to the looming threat of retaliation from the paramilitary groups, which have effectively defeated the guerrillas in this part of northern Colombia. “I learned that if I interest just one person in reading a mundane news item — say, about the rising price of rice — then that’s a step forward.”

Such victories keep Mr. Soriano going, despite the challenges that come with running the Biblioburro.
He fractured his left leg in a fall from one of his burros in July, leaving him with a limp. And some of his readers like the books they borrow so much that they fail to return them.
Two books that vanished not long ago: an illustrated sex education manual, and a copy of “Like Water for Chocolate,” the Mexican writer Laura Esquivel’s novel about food and love in a traditional Mexican family.
And there are dangers inherent to venturing into the backlands around La Gloria. Two years ago, Mr. Soriano said, bandits surprised him at a river crossing, found that he carried almost no money, and tied him to a tree. They stole one item from his book pouch: “Brida,” the story of an Irish girl and her search for knowledge, by the Brazilian novelist Paulo Coelho.
“For some reason, Paulo Coelho is at the top of everyone’s list of favorites,” said Mr. Soriano, hiding a grin under the shade of his sombrero vueltiao, the elaborately woven cowboy hat popular in Colombia’s interior.
On a trip this month into the rutted hills, where about 300 people regularly borrow books from him, he reminisced about a visit to the National Library in the capital, Bogotá, where he was stunned by the building’s immense collection and its Art Deco design.
“I felt so ordinary in Bogotá,” Mr. Soriano said. “My place is here.”
At times, on the remote landscape dotted with guayacán trees, it was hard to tell whether beast or man was in control. Once, Mr. Soriano lost his patience, trying to coax his stubborn donkeys to cross a stream.
Still, it was clear why Mr. Soriano does what he does.
In the village of El Brasil, Ingrid Ospina, 18, leafed through a copy of “Margarita,” the classic book of poetry by Rubén Darío of Nicaragua, and began to read aloud.
She went beyond where the heavens are
and to the moon said, au revoir.
How naughty to have flown so far
without the permission of Papa.
“That is so beautiful, Maestro,” Ms. Ospina said to the teacher. “When are you coming back?”

mercoledì 8 ottobre 2008

An Eye on the Swarm

http://www.princeton.edu/~icouzin/

http://es.youtube.com/watch?v=RbxDLjcosss


http://es.youtube.com/watch?v=RVvcX8HWghA

martedì 7 ottobre 2008

From Ants to People, an Instinct to Swarm 1-2

http://www.nytimes.com/2007/11/13/science/13traff.html?pagewanted=1&_r=1

If you have ever observed ants marching in and out of a nest, you might have been reminded of a highway buzzing with traffic. To Iain D. Couzin, such a comparison is a cruel insult — to the ants.
Americans spend a 3.7 billion hours a year in congested traffic. But you will never see ants stuck in gridlock.
Army ants, which Dr. Couzin has spent much time observing in Panama, are particularly good at moving in swarms. If they have to travel over a depression in the ground, they erect bridges so that they can proceed as quickly as possible.
“They build the bridges with their living bodies,” said Dr. Couzin, a mathematical biologist at
Princeton University and the University of Oxford. “They build them up if they’re required, and they dissolve if they’re not being used.”
The reason may be that the ants have had a lot more time to adapt to living in big groups. “We haven’t evolved in the societies we currently live in,” Dr. Couzin said.
By studying army ants — as well as birds, fish, locusts and other swarming animals — Dr. Couzin and his colleagues are starting to discover simple rules that allow swarms to work so well. Those rules allow thousands of relatively simple animals to form a collective brain able to make decisions and move like a single organism.
Deciphering those rules is a big challenge, however, because the behavior of swarms emerges unpredictably from the actions of thousands or millions of individuals.
“No matter how much you look at an individual army ant,” Dr. Couzin said, “you will never get a sense that when you put 1.5 million of them together, they form these bridges and columns. You just cannot know that.”
To get a sense of swarms, Dr. Couzin builds computer models of virtual swarms. Each model contains thousands of individual agents, which he can program to follow a few simple rules. To decide what those rules ought to be, he and his colleagues head out to jungles, deserts or oceans to observe animals in action.
Daniel Grunbaum, a mathematical biologist at the
University of Washington, said his field was suddenly making leaps forward, as math and observation of nature were joined in the work of Dr. Couzin and others. “In the next 10 years there’s going to be a lot of progress.”
He said Dr. Couzin has been important in fusing the different kinds of science required to understand animal group behavior. “He’s been a real leader in bringing a lot of ideas together,” Dr. Grunbaum said. “He has a larger vision. If it works, that’ll be a big advance.”
In the case of army ants, Dr. Couzin was intrigued by their highways. Army ants returning to their nest with food travel in a dense column. This incoming lane is flanked by two lanes of outgoing traffic. A three-lane highway of army ants can stretch for as far as 150 yards from the ant nest, comprising hundreds of thousands of insects.
What Dr. Couzin wanted to know was why army ants do not move to and from their colony in a mad, disorganized scramble. To find out, he built a computer model based on some basic ant biology. Each simulated ant laid down a chemical marker that attracted other ants while the marker was still fresh. Each ant could also sweep the air with its antennas; if it made contact with another ant, it turned away and slowed down to avoid a collision.
Dr. Couzin analyzed how the ants behaved when he tweaked their behavior. If the ants turned away too quickly from oncoming insects, they lost the scent of their trail. If they did not turn fast enough, they ground to a halt and forced ants behind them to slow down. Dr. Couzin found that a narrow range of behavior allowed ants to move as a group as quickly as possible.
It turned out that these optimal ants also spontaneously formed highways. If the ants going in one direction happened to become dense, their chemical trails attracted more ants headed the same way. This feedback caused the ants to form a single packed column. The ants going the other direction turned away from the oncoming traffic and formed flanking lanes.
To test this model, Dr. Couzin and Nigel Franks, an ant expert at the University of Bristol in England, filmed a trail of army ants in Panama. Back in England, they went through the film frame by frame, analyzing the movements of 226 ants. “Everything in the ant world is happening at such a high tempo it was very difficult to see,” Dr. Couzin said.

Eventually they found that the real ants were moving in the way that Dr. Couzin had predicted would allow the entire swarm to go as fast as possible. They also found that the ants behaved differently if they were leaving the nest or heading back. When two ants encountered each other, the outgoing ant turned away further than the incoming one. As a result, the ants headed to the nest end up clustered in a central lane, while the outgoing ants form two outer lanes. Dr. Couzin has been extending his model for ants to other animals that move in giant crowds, like fish and birds. And instead of tracking individual animals himself, he has developed programs to let computers do the work.
The more Dr. Couzin studies swarm behavior, the more patterns he finds common to many different species. He is reminded of the laws of physics that govern liquids. “You look at liquid metal and at water, and you can see they’re both liquids,” he said. “They have fundamental characteristics in common. That’s what I was finding with the animal groups — there were fundamental states they could exist in.”
Just as liquid water can suddenly begin to boil, animal swarms can also change abruptly thanks to some simple rules.
Dr. Couzin has discovered some of those rules in the ways that locusts begin to form their devastating swarms. The insects typically crawl around on their own, but sometimes young locusts come together in huge bands that march across the land, devouring everything in their path. After developing wings, they rise into the air as giant clouds made of millions of insects.
“Locusts are known to be around all the time,” Dr. Couzin said. “Why does the situation suddenly get out of control, and these locusts swarm together and devastate crops?”
Dr. Couzin traveled to remote areas of Mauritania in Africa to study the behavior of locust swarms. Back at Oxford, he and his colleagues built a circular track on which locusts could walk. “We could track the motion of all these individuals five times a second for eight hours a day,” he said.
The scientists found that when the density of locusts rose beyond a threshold, the insects suddenly began to move together. Each locust always tried to align its own movements with any neighbor. When the locusts were widely spaced, however, this rule did not have much effect on them. Only when they had enough neighbors did they spontaneously form huge bands.
“We showed that you don’t need to know lots of information about individuals to predict how the group will behave,” Dr. Couzin said of the locust findings, which were published June 2006 in Science.
Understanding how animals swarm and why they do are two separate questions, however.
In some species, animals may swarm so that the entire group enjoys an evolutionary benefit. All the army ants in a colony, for example, belong to the same family. So if individuals cooperate, their shared genes associated with swarming will become more common.
But in the deserts of Utah, Dr. Couzin and his colleagues discovered that giant swarms may actually be made up of a lot of selfish individuals.
Mormon crickets will sometimes gather by the millions and crawl in bands stretching more than five miles long. Dr. Couzin and his colleagues ran experiments to find out what caused them to form bands. They found that the forces behind cricket swarms are very different from the ones that bring locusts together. When Mormon crickets cannot find enough salt and protein, they become cannibals.
“Each cricket itself is a perfectly balanced source of
nutrition,” Dr. Couzin said. “So the crickets, every 17 seconds or so, try to attack other individuals. If you don’t move, you’re likely to be eaten.”
This collective movement causes the crickets to form vast swarms. “All these crickets are on a forced march,” Dr. Couzin said. “They’re trying to attack the crickets who are ahead, and they’re trying to avoid being eaten from behind.”
Swarms, regardless of the forces that bring them together, have a remarkable ability to act like a collective mind. A swarm navigates as a unit, making decisions about where to go and how to escape predators together.
“There’s a swarm intelligence,” Dr. Couzin said. “You can see how people thought there was some sort of telekinesis involved.”

What makes this collective decision-making all the more puzzling is that each individual can behave only based on its own experience. If a shark lunges into a school of fish, only some of them will see it coming. If a flock of birds is migrating, only a few experienced individuals may know the route.
Dr. Couzin and his colleagues have built a model of the flow of information through swarms. Each individual has to balance two instincts: to stay with the group and to move in a desired direction. The scientists found that just a few leaders can guide a swarm effectively. They do not even need to send any special signals to the animals around them. They create a bias in the swarm’s movement that steers it in a particular direction.
“It doesn’t necessarily mean you have the right information, though,” Dr. Couzin pointed out.
Two leaders may try to pull a swarm in opposite directions, and yet the swarm holds together. In Dr. Couzin’s model, the swarm was able to decide which leaders to follow.
“As we increased the difference of opinion between the informed individuals, the group would spontaneously come to a consensus and move in the direction chosen by the majority,” Dr. Couzin said. “They can make these decisions without mathematics, without even recognizing each other or knowing that a decision has been made.”
Dr. Couzin and his colleagues have been finding support for this model in real groups of animals. They have even found support in studies on mediocre swarmers — humans.
To study humans, Dr. Couzin teamed up with researchers at the University of Leeds. They recruited eight people at a time to play a game. Players stood in the middle of a circle, and along the edge of the circle were 16 cards, each labeled with a number. The scientists handed each person a
slip of paper and instructed the players to follow the instructions printed on it while not saying anything to the others. Those rules correspond to the ones in Dr. Couzin’s models. And just as in his models, each person had no idea what the others had been instructed to do.
In one version of the experiment, each person was instructed simply to stay with the group. As Dr. Couzin’s model predicted, they tended to circle around in a doughnut-shaped flock. In another version, one person was instructed to head for a particular card at the edge of the circle without leaving the group. The players quickly formed little swarms with their leader at the head, moving together to the target.
The scientists then sowed discord by telling two or more people to move to opposite sides of the circle. The other people had to try to stay with the group even as leaders tried to pull it apart.
As Dr. Couzin’s model predicted, the human swarm made a quick, unconscious decision about which way to go. People tended to follow the largest group of leaders, even if it contained only one additional person.
Dr. Couzin and his colleagues describe the results of these experiments in a paper to be published in the journal Animal Behavior.
Dr. Couzin is carrying the lessons he has learned from animals to other kinds of swarms. He is helping Dr. Naomi Leonard, a Princeton engineer, to program swarming into robots.
“These things are beginning to move around and interact in ways we see in nature,” he said. Ultimately, flocks of robots might do a better job of collecting information in dangerous places. “If you knock out some individual, the algorithm still works. The group still moves normally.” The rules of the swarm may also apply to the cells inside our bodies. Dr. Couzin is working with
cancer biologists to discover the rules by which cancer cells work together to build tumors or migrate through tissues. Even brain cells may follow the same rules for collective behavior seen in locusts or fish.
“One of the really fun things that we’re doing now is understanding how the type of feedbacks in these groups is like the ones in the brain that allows humans to make decisions,” Dr. Couzin said. Those decisions are not just about what to order for lunch, but about basic perception — making sense, for example, of the flood of signals coming from the eyes. “How does your brain take this information and come to a collective decision about what you’re seeing?” Dr. Couzin said. The answer, he suspects, may lie in our inner swarm.

From Ants to People, an Instinct to Swarm 2-2



mercoledì 1 ottobre 2008

Growing Pains for a Deep-Sea Home Built of Subway Cars






SLAUGHTER BEACH, Del. — Sixteen nautical miles from the Indian River Inlet and about 80 feet underwater, a building boom is under way at the Red Bird Reef.
One by one, a machine operator has been shoving hundreds of retired New York City subway cars off a barge, continuing the transformation of a barren stretch of ocean floor into a bountiful oasis, carpeted in sea grasses, walled thick with blue mussels and sponges, and teeming with black sea bass and tautog.
“They’re basically luxury condominiums for fish,” Jeff Tinsman, artificial reef program manager for the
Delaware Department of Natural Resources and Environmental Control, said as one of 48 of the 19-ton retirees from New York City sank toward the 666 already on the ocean floor.
But now, Delaware is struggling with the misfortune of its own success.
Having planted a thriving community in what was once an underwater desert, state marine officials are faced with the sort of overcrowding, crime and traffic problems more common to terrestrial cities.
The summer flounder and bass have snuggled so tightly on top and in the nooks of the subway cars that Mr. Tinsman is trying to expand the housing capacity. He is having trouble, however, because other states, seeing Delaware’s successes, have started competing for the subway cars, which New York City provides free.
Crisscrossing over the reef, commercial pot fishermen keep getting their lines tangled with those of smaller hook-and-reel anglers, and the rising tension has led the state to ask federal marine officials to declare the area off limits to large commercial fishermen.
As the reef has become more popular, theft and sabotage of fishing traps and pots has more than doubled in the last several years, said Capt. David Lewis of the Delaware Bay Launch Service. “People now don’t just steal the fish inside the pots out here, they’ve started stealing the pots, too,” he said.
The reef, named after New York City’s famous Redbird subway cars, now supports more than 10,000 angler trips annually, up from fewer than 300 in 1997. It has seen a 400-fold increase in the amount of marine food per square foot in the last seven years, according to state data.
Mr. Tinsman said his department was doing everything it could to expand the capacity, noting that last year, when subway cars were unavailable, he sank a 92-year-old tugboat and the YOG-93, a 175-foot decommissioned Navy tanker built in 1945 for the planned invasion of Japan. Fifty subway cars are due this month, he said.
“The secret is out, I guess,” said Michael G. Zacchea, the Metropolitan Transportation Authority official in charge of getting rid of New York City’s old subway cars.
Mr. Zacchea added that Delaware’s prospects for expanding the reef looked grim because New York State has said it wanted all of the city’s retired subway cars once the United States Army Corps of Engineers updates the state’s reef permit this summer. Mr. Zacchea said he would soon stop shipments out of state, saving perhaps $2 million in transport costs. As a good faith gesture, the city probably will provide about 100 cars to Delaware, Maryland, Virginia and New Jersey before out-of-state deliveries are halted.
While New York State works to get its permit in place, other states are pushing hard to get what they can from the city, Mr. Zacchea said.
Last month, for example, New Jersey, which stopped taking the cars in 2003 because of environmental concerns, asked the city for 600 of them.
Tim Dillingham, the executive director of the American Littoral Society, a coastal conservation group based in Sandy Hook, N.J., said natural rock and concrete balls were far safer and more durable materials for artificial reefs.
“Those materials also cost more, and we’re sensitive to the realities of budget crunches in many states,” Mr. Dillingham said.
The American Littoral Society and other environmental groups opposed the use of the Redbird cars because they have small levels of asbestos in the glue used to secure the floor panels and in the insulation material in the walls.
State and federal environmental officials approved the use of the Redbirds and other cars for artificial reefs in Delaware and elsewhere because they said the asbestos was not a risk for marine life and has to be airborne to pose a threat to humans.
Mr. Dillingham said his group had pushed New Jersey to use only New York City’s cars, which have only stainless steel on the outside, contain less asbestos and are more durable. Delaware, which oversees nine artificial reef sites in state waters and five, including Red Bird Reef, in federal waters, was the first state to get subway cars from New York City, in August 2001.
In the last several years, the reefs have drawn swift open-ocean fish, like tuna and mackerel, that use the reefs as hunting grounds for smaller prey. Sea bass like to live inside the cars, while large flounder lie in the silt that settles on top of the cars, said Mr. Tinsman, the Delaware official.
States have experimented with other types of artificial reef materials, including abandoned automobiles, tanks, refrigerators, shopping carts and washing machines.
Mr. Tinsman particularly favors the newer subway cars with stainless steel on the outside to create reefs. “We call these the DeLoreans of the deep,” he said.
Subway cars in general, he said, are roomy enough to invite certain fish, too heavy to shift easily in storms and durable enough to avoid throwing off debris for decades.
“The one problem I see with them,” Mr. Tinsman said, “is that just like the DeLoreans, there are only a limited
number.”

España, bajo el estrés del agua

+
Un informe de la Agencia Europea de Medio Ambiente afirma que el país vivirá sus próximos años entre inundaciones y sequías
El estrés del agua quiere decir sequía y desertificación. Significa que en el futuro, a nuestra lista de preocupaciones, se añadirá la falta de agua. Pero también el exceso: inundaciones y crecidas de ríos. Es la expresión que utiliza la Agencia Europea de Medio Ambiente (EEA) para calificar lo que va a sufrir en las próximas décadas España y todos los países de la cuenca del Mediterráneo.
La Unión Europea ha publicado un informe llamado Impactos del cambio climático en Europa que especifica las convulsiones que vivirá el viejo continente por el calentamiento global. El estudio analiza la cantidad del agua que el hombre ha necesitado entre 1975 y 2006 y, por otro lado, muestra la evidencia de que las lluvias serán muy intermitentes en Europa. Lloverá poco y se necesitará más agua. "En el mismo período ha habido un significativo incremento en la demanda de agua en España (entre el 50% y el 70%) y en las áreas mediterráneas", asevera el informe. Y las predicciones de futuro van en línea ascendente. "La demanda crecerá cada vez más, especialmente en el sur donde la necesidad de agua para la agricultura es mayor. Con ella, se desarrollará una competición por este bien entre los distintos sectores (turismo, agricultura, energía) y usos".
En promedio, la exigencia de agua en todos los países de Europa ha crecido al rededor de 50 milímetros cúbicos por hectárea al año pero, en algunos casos como en el centro de España, Italia, Grecia, el Magreb, el sur de Francia y Alemania la cifra oscila entre 150 y 200 metros cúbicos por hectárea al año. Y, como se prevé que las lluvias, se reducirán se necesitará regar más. Por eso la falta de agua causará un impacto negativo tanto en términos económicos como en ecológicos. Además, en el Mediterráneo se ha observado un creciente déficit del agua en los últimos 32 años.
Aunque el informe vaticina desertización para España, el estudio tampoco nos libra de los desbordamientos de los ríos. Habrá un incremento porque la alternancia entre períodos de sequía y precipitaciones torrenciales hace a España más propensa a estas inundaciones. Para 2080 pronostica que entre 2000 y 4000 personas se verán afectadas por las inundaciones en las zonas costeras por la subida del nivel del mar en Andalucía, Galicia, las Islas Baleares y Asturias. La región más afectada será el País Vasco: entre 4000 y 8000 personas podrán ser víctimas de la subida del mar. Países como Reino Unido, Sicilia o Grecia podrán ver afectada a gran parte de su población (entre 8000 y 50.000 personas). El planeta ya está experimentando una subida de las temperaturas de 0,8 grados centígrados por encima de los niveles preindustriales y el nivel del mar ha crecido 3,1 milímetros al año en los últimos 15 años.
Para mitigar todos estos problemas el informe apuesta tanto por la reducción del CO2 como por la adaptación a las consecuencias del cambio que ya no se pueden remediar. "El 90% de todos los desastres que han sucedido en Europa desde 1980 están directa o indirectamente relacionados con el clima y representan el 95% de las pérdidas económicas causadas por catástrofes", señala el informe.
Para evitar estas pérdidas se pone tres metas: la primera, una mayor vigilancia, monitorización y estudio de los cambios a nivel internacional; la segunda, estabilizar el clima para 2020 por debajo de los dos grados centígrados con respecto a los niveles pre industriales "para evitar consecuencias irreversibles en la sociedad y en los ecosistemas". Por último, hace hincapié en la adaptación.
Afirma que uno de los grandes retos de España de todo el Mediterráneo en adaptación es la diversificación del turismo en otros sectores. El estudio asegura que la subida de la temperatura hará marcharse a los turistas más al norte, en busca del mismo clima que antes se gozaba en España. Por eso, para no perder dinero, será imprescindible invertir en otros sectores.