Transparent Nuclei

Transparent Nuclei

Skinny particles. An electron (bright green) has just scattered from a nucleus and created a pion (green-skinned particle). This pion's quarks are so tightly packed that they nearly cancel each other's color charge, allowing the pion to slip through the nucleus without interacting, an effect now seen at the lowest possible energies.

A two-quark particle shot into a large nucleus is ordinarily absorbed, as its quarks interact with the nuclear quarks. But in some cases it can sail right through. Now a team reports in the 14 December Physical Review Letters that they have observed this so-called color transparency in the lower energy realm, where such quark-scale effects aren't normally seen. The results--which are somewhat controversial--could help theorists who hope to bring the clean calculations of high energy, particle physics down into the messy world of lower energy nuclear physics.

Quarks have a "color" that attracts them to one another, somewhat like an electric charge. This force binds them together in threes (for protons and neutrons) or in twos (for pions and other mesons). The theory of quark interactions--quantum chromodynamics, or QCD--predicts that a quark-containing particle has a range of states with different physical sizes, from small to large. The particle's measured size is an average over these different configurations, which exist simultaneously. QCD also says that a particle created at sufficiently high energy will start out in a small configuration with its quarks practically sitting on top of each other. In this short-lived state, the quarks will neutralize each other's color, making the particle temporarily invisible to other quarks and thus able to escape the nucleus. This color transparency state is similar to a very small electric dipole, whose positive and negative charges nearly cancel each other out.

To observe the effect, researchers look for particles that form on one side of a nucleus and escape through the other side before expanding to normal size. Color transparency has been observed at energies above about 50 GeV, where QCD is relatively easy to calculate. But it should also exist at lower energies, where the theory of nuclear interactions is more challenging. One approach to those harder calculations is to divide the problem into two parts--for example, one involving smaller, "transparent" pion states, for which there is a good high-energy theory, and another involving larger pion states, says Gerald Miller of the University of Washington in Seattle. So documenting transparency at the lowest possible energies could help researchers solve some tough theory problems, he says.

Miller and his experimentalist colleagues, using the electron beam at Jefferson Lab in Newport News, Virginia, report evidence of the onset of color transparency in medium-energy pions. The researchers studied collisions between 5 GeV electrons and various nuclear targets and carefully selected those events in which an electron struck a proton inside a nucleus, transforming it into a neutron and emitting a positively-charged pion. The fraction of pions that passed through the nucleus without being absorbed increased with energy. With a carbon target, for example, 60 percent of the pions having 2.5 GeV of energy escaped, whereas 75 percent of those with 5 GeV escaped. This energy-dependent absorption is not seen with pions created some distance away from a nucleus (with time to expand to normal size), so the team believes it has seen signs of color transparency. The results appear to match theoretical predictions by Miller and others.

But some researchers are skeptical that pions of small initial size can be completely sorted out from the huge background of normal-sized pions. Kawtar Hafidi of Argonne National Lab in Illinois and her colleagues have preliminary results with rho mesons--a cleaner test than pions, they believe--that do not show the same expected energy dependence, so she finds the new paper "hard to believe." But team member Dipangkar Dutta of Mississippi State University says his group's data also exhibit a dependence on nuclear size, which is further proof of color transparency. 

Aging AIDS patients beset by complex health problems

Aging AIDS patients beset by complex health problems
 

John Holloway, 59, in his apartment designed for the frail elderly. He suffers from illnesses more severe than those of his father, 84. 

John Holloway received a diagnosis of AIDS nearly two decades ago, when the disease was a speedy-death sentence and treatment a distant dream.

Yet at 59 he is alive, thanks to a cocktail of drugs that changed the course of an epidemic. But with longevity has come a host of unexpected medical conditions, which challenge the prevailing view of AIDS as a manageable, chronic disease.

Holloway, who lives in a housing complex designed for the frail elderly, suffers from complex health problems usually associated with advanced age: chronic obstructive pulmonary disease, diabetes, kidney failure, a bleeding ulcer, severe depression, rectal cancer and the lingering effects of a broken hip.

Those illnesses, more severe than those of his 84-year-old father, are not what Holloway expected when lifesaving antiretroviral drugs became the standard of care in the mid-1990s.

The drugs gave Holloway back his future. But at what cost?

That is the question, heretical to some, that is now being voiced by scientists, doctors and patients encountering a constellation of ailments showing up prematurely or in disproportionate numbers among the first wave of AIDS survivors to reach late middle age.

There have been only small, inconclusive studies on the causes of aging-related health problems among AIDS patients. Without definitive research, which has just begun, that second wave of suffering could be a coincidence, although it is hard to find anyone who thinks so.

Instead, experts are coming to believe that the immune system and organs of long-term survivors took an irreversible beating before the advent of lifesaving drugs, and that those very drugs then produced additional complications because of their toxicity - a one-two punch.

"The sum total of illnesses can become overwhelming," said Dr. Charles Emlet, an associate professor at the University of Washington at Tacoma and a leading researcher on HIV and aging, who sees new collaborations between specialists that will improve care.

"AIDS is a very serious disease, but longtime survivors have come to grips with it," Emlet continued, explaining that while some patients experienced unpleasant side effects from the antiretrovirals, a vast majority found a cocktail they could tolerate.

"Then all of a sudden they are bombarded with a whole new round of insults, which complicate their medical regime and have the potential of being life threatening. That undermines their sense of stability and makes it much more difficult to adjust."

The graying of the AIDS epidemic has increased interest in the connection between AIDS and cardiovascular disease, certain cancers, diabetes, osteoporosis and depression. The number of people 50 and older living with HIV, the virus that causes AIDS, has increased 77 percent from 2001 to 2005, according to the U.S. Centers for Disease Control, and they now represent more than a quarter of all cases in the United States.

The most comprehensive research has come from the AIDS Community Research Initiative of America, which has studied 1,000 long-term survivors in New York City, and the Multi-Site AIDS Cohort Study, financed by the National Institutes of Health, which has followed 2,000 subjects nationwide for the past 25 years.

The Acria study, published in 2006, examined psychological, not medical, issues and found unusual rates of depression and isolation among older people with AIDS.

The Multi-Site AIDS Cohort Study will directly examine the intersection of AIDS and aging over the next five years. Dr. John Phair, a principal investigator for the study, which has health data from both infected and uninfected men, said "prolonged survival" coupled with the "naturally occurring health issues" of old age raised pressing research questions: "Which health issues are a direct result of aging, which are a direct result of HIV, and what role do HIV meds play?"

The MACS investigators, and other researchers, defend the slow pace of research as a function of numbers. The first generation of AIDS patients, in the mid-1980s, had no effective treatments for a decade, and died in overwhelming numbers, leaving few survivors to study.

Those survivors, like Holloway, gaunt from chemotherapy and radiation and mostly housebound, lurch from crisis to crisis. Holloway says his adjustment strategy is simple: "Deal with it."

Still, he notes ruefully that his father has no medical complaints other than arthritis, failing eyesight and slight hearing loss. "I look at how gracefully he's aged, and I wish I understood what was happening to my body," Holloway said during a recent home visit by his case manager at the Howard Brown Health Center here, a gay, lesbian and transgender organization.

The case manager, Lisa Katona, could soothe but not inform him.

"Nobody's sure what causes what," Katona told Holloway. "You folks are the first to go through this, and we're learning as we go."

There are no data that compare the incidence, age of onset and cause of geriatric diseases in the general population with the long-term survivors of HIV infection. But physicians and researchers say that they do not see people in their mid-50s, absent AIDS, with hip replacements associated with vascular necrosis, heart disease or diabetes related to lipodystrophy, or osteoporosis without the usual risk factors.

"All we can do right now is make inferences from thing to thing to thing," said Dr. Tom Barrett, medical director of Howard Brown.

"They might have gotten some of these diseases anyway. But the rates and the timing, and the association with certain drugs, makes everyone feel this is a different problem."

One theory about why research on AIDS and aging has barely begun is "the rapid increase in numbers," Emlet said. The federal disease centers' most recent surveillance data, from 33 states that meet certain reporting criteria, showed that the number of people 50 and older with AIDS or HIV infection was 115,871 in 2005, nearly double the 64,445 in 2001.

Another is the routine exclusion of older people from drug trials by big pharmaceutical companies. The studies are designed to measure safety and efficacy but generally not long-term side effects.

Those explanations do not satisfy Larry Kramer, the founder of several AIDS advocacy groups. Kramer, 73 and a long-term survivor, said he had always suspected "it was only a matter of time before stuff like this happened," given the potency of the antiretroviral drugs. "How long will the human body be able to tolerate that constant bombardment?" he asked. "Well, we are now seeing that many bodies can't. Once again, just as we thought we were out of the woods, sort of, we have good reason again to be really scared."

The lack of research also limits a patient's care. Barrett says the incidence of osteoporosis warrants routine screening. In the United States, however, Medicare, Medicaid and private insurers will not cover bone density tests for middle-aged men.

Marty Weinstein, 55 and infected since 1982, has had a pacemaker installed, has been found to have osteoporosis and has been treated for anal cancer and medicated for severe depression - all in the last year. He also has cognitive deficits.

A former professor of psychology in Chicago, he presses his doctors about cause and effect. Sometimes they offer a hypothesis, he said, but never a certain explanation.

"I know the first concern was keeping us alive," Weinstein said.

"But now that so many people are going to live longer lives, how are we going to get them through this emotionally and physically?"

Seeds to Save a Species

Seeds to Save a Species

To visit the Shola market, a teeming maze of stalls in Addis Ababa, Ethiopia, you'd never know that the human race's food supply was in jeopardy. Massive sacks stuffed with dried chili peppers overflow onto piles of vegetables—potatoes, beets, carrots, onions, tomatoes. Enticing smells waft from the spice sellers' stalls, crowded with colorful mounds of cumin, turmeric and ginger.

Wandering the market's muddy corridors, Luigi Guarino stoops to smell frankincense and examine fistfuls of legumes. To the casual observer, they're just sacks full of beans. But to the 48-year-old crop scientist, each one is a tiny buffer against worldwide starvation. Guarino fingers the dried seeds with reverence, because he understands how valuable—and fragile—they really are. He has spent much of his career trolling remote and exotic lands, gathering the genetic diversity of the plants that sustain humanity. His work has taken him to roadless villages in Oman's mountains and across the desolate Sahara between Algeria and Niger, all in search of crop varieties with unique traits that could someday save the world's harvest—and its people—from infestation, blight or drought.

Looking up, Guarino explains that in certain countries, industrial progress has left some of the world's most important food crops at risk of obliteration. When it comes to gathering food, "people used to be more mobile," he says, as the beans sift through his fingers. "Now they have nowhere to go. They're more vulnerable to things like drought. As population increases and more farmland is converted to urban areas, you have less land on which to produce more food."

Meanwhile, because the efficiency of modern farming has made crops so genetically uniform, the plants on which humans depend—those we've bent to our will over thousands of years—are at the mercy of chance. They simply aren't diverse enough anymore. To endure, crop plants, like their wild counterparts, need varied gene pools. But the genetic diversity of our food supplies is withering. In the past 200 years in the U.S. alone, 75 percent of the variety within crops has vanished. That's a disaster waiting to happen.

To help prepare for the worst, in February the Norwegian government, together with the Global Crop Diversity Trust, an organization in Rome for which Guarino now serves as science coordinator, will unveil an immense fortress, the Svalbard Global Seed Vault, built on a frigid, wind-whipped archipelago in the Arctic Ocean, 600 miles from Norway.

The Crop Trust's mission is to safeguard agriculture, and it has raised more than $130 million of a $260-million goal to do so. It plans to permanently endow a network of seed and gene banks—archives of essential plant materials—around the world. The Svalbard vault is its ultimate defensive measure: a last-ditch reserve, ready if all else fails.

Dug nearly 400 feet deep into a sandstone mountain, the vault's interior temperature is immune to changes in the surrounding permafrost. It sits roughly 425 feet above sea level, protected against flood even if all of Antarctica were to melt. The entry tunnel passes through a series of steel doors and a highly sophisticated video surveillance system before reaching three chambers capable of holding 4.5 million samples of vital crop seeds. Safe from nuclear warfare, terrorist attacks, natural disasters and global warming, the seeds stockpiled at Svalbard just might revive our food stores in the event of a global catastrophe. Svalbard's feasibility study, conducted by an international team of scientists, concluded, "Our existence on earth rests on how well we take care of these seeds; and their existence depends on us."

Deep Storage North of mainland Norway, two security doors and three airlocks protect the cave's contents.

But before they can be dehydrated, sealed in special foil packages, and laid in their frozen resting place, the seeds must first be collected in the field. Guarino is part of a small but dedicated band of such seed collectors.

They're a far-flung bunch. From Aleppo, Syria, where he curates one of the most important collections of wheat and the wild ancestors with which it shares genes, an intrepid Australian named Ken Street leads annual expeditions across lawless tracts of central Asia and the Caucasus in search of new genes for dry climates. Daniel Debouck, an ebullient Belgian scientist based in Cali, Colombia, has spent three decades roaming the Americas on the trail of unique beans. "He's married to the bean," Guarino jokes, "but recently he had an affair with a cassava." And dozens of other crop scientists, botanists and biologists each struggle, on meager budgets, to retrieve seeds from similarly remote and dangerous regions.

Uprooted "This is the only world problem we know we can solve at this point in history," says Cary Fowler, the man behind Svalbard.

Why Diversity Matters
If the word "biodiversity" triggers any associations for you, they probably have to do with rainforests and gorillas, not fields of neatly planted corn, peas and pineapples. But agricultural crops are subject to the same basic laws of biology and natural selection as all living things. To adapt and evolve, to survive disease and adjust to changing environmental conditions, their gene pool must be a mixed bag.

Crop yields will need to roughly double in the next 50 years to keep up with the pace of population growth. As a result, protecting agricultural biodiversity is more important than ever, and the preservation of raw material necessary for crops to adapt is "the most fundamental thing you can do to ensure their survival," says Cary Fowler, a native Tennessean who is the Global Crop Diversity Trust's executive director and the main visionary behind Svalbard.

The raw genetic materials are stored in gene banks all over the world as seeds, plant tissue and whole plants, which these banks then loan out. Farmers and breeders can obtain plant material to grow in the field or to use for breeding specific traits. But these banks are also an archive, and preserving the genetic material is a complex undertaking. Some seeds can survive frozen for decades but must still be periodically thawed, tested for viability, and regrown—a time-consuming operation. Other plants don't respond well to the drying and freezing process. Apples, for instance, should instead be cryogenically frozen, an expensive effort impossible at all but the best-funded gene banks, like the U.S. Department of Agriculture facility in Fort Collins, Colorado. Coffee plants, meanwhile, need to be continuously grown in the field. And still more plants are cultured and stored in test tubes, which takes a great deal of time and money.

Preserving crop plants in gene banks is a hedge against unknown future threats. It ensures that diversity will be there when breeders need it to breed plants that are tolerant of saltier soils, for example, or resistant to invading insects. "You don't actually know what will be needed by what country when," says Julian Laird, the Crop Trust's director of development. "It could be in Rwanda or it could be in Colorado."

Gene banks are one of the few reliable sources of plant material that might save the day. A breeder whose country faces a particular infestation will need to experiment with a wide variety of genetic material within that crop to find a resistant gene. "My job," Street says, "is to put together big gene pools so that breeders can dig into them." Street's facility in Syria may look like nothing but a tidy storehouse for a few crops, he explains, but within that collection there's a wide variety of genetic material. "Wheat from the highlands of Ethiopia is likely to be very different than wheat from the highlands of Turkmenistan because they evolved to be quite different—just as you have a Pygmy perfectly adapted to running through a forest and a Dinka adapted to running through the plains."

An international network of gene banks called the Consultative Group on International Agricultural Research (CGIAR) stores collections of many crops, with funding from the World Bank, the Food and Agriculture Organization of the United Nations and others. Debouck and Street each curate CGIAR centers, which serve as a home base for their field expeditions. Many countries also maintain their own gene banks, and those sometimes house the only specimens of a particular seed variety.

Similarly, the Global Crop Diversity Trust is trying to create a linked chain of gene banks by endowing the most important of them around the world. "Gene banks are clearly one of the basic building blocks of a healthy agricultural system," says Roy Steiner, a senior program officer in agricultural development at the Gates Foundation, which gave $30 million to the Trust. "It's this library that nature has given us from millions of years of evolution, and the fact that we're allowing these incredible books to be lost is a tragedy."

Gene banks tend to be underfunded, disorganized, and located in hard-luck places, partly because much of the planet's genetic diversity arose in what are now the poorest countries. Many of the 1,400 facilities around the world that describe themselves as gene banks are, Fowler says, places "where you wouldn't want to store a kid's milk for lunch."

Before it gained notoriety for its prison, Abu Ghraib was the site of Iraq's national seed bank. It was destroyed and looted after the 2003 American invasion, its collections of lentils, rye, barley and other seeds gone forever. Afghanistan's seed bank was obliterated during mujahadeen fighting in the 1990s; a clandestine seed collection established afterward and hidden in a private house in Jalalabad was also looted—robbed for the plastic bottles used to store the seeds. In 1985, a starving group of homeless people broke into Peru's National Agricultural Institute and made off with its sweet-potato collection. Last year, a typhoon washed away the Philippines's gene bank—countless variations of sweet potato, taro and banana carried off in a river of mud.

What did we lose, exactly? It's impossible to say. "The problem in explaining it to the public," Fowler says, "is we don't know what was lost. And you can say, 'Well so what?' And I can't answer, 'Well, what we've lost was the last form of resistance to a disease that we're going to encounter five years from now.' "

Until the End of the World The vault can store 4.5 million seeds within its reinforced-concrete walls, dug nearly 400 feet into the mountainside. A ventilation system will pump in Arctic air when it's cold enough; if the temperature in the vault rises above –0.4ºF, a complex refrigeration system will kick in. A fiber-optic monitoring network will keep close tabs on climate conditions and transmit images of the vault's interior to the University Center in Svalbard and to the nearby Nordic Gene Bank.

Saving the World, Invisibly
The foot soldiers of biodiversity have an extraordinarily important mission, but the particular irony of their efforts is that if things turn out as they hope, and the biodiversity of plant life is preserved, the material they bring back to the impenetrable vault in Norway will never truly be needed. If all goes well, no one will know the lengths to which scientists like Guarino and Fowler went.

Anonymity and thanklessness have always been part of this work. Across the sprawl and chaos of Addis Ababa from the Shola Market is the Institute for Biodiversity Conservation. Guarino has come to Addis with Fowler to discuss an endowment for the Ethiopian national gene bank and its relationship with the Svalbard vault. For three hours, the two men sit with a group of Ethiopian officials, sipping thick sweetened coffee and snacking on roasted barley as they hammer out an agreement to ensure the continued safety of the country's collections of nine crucial cereal crops.

Downstairs, the objects of their attention are waiting, vacuum-sealed and frozen: wheat, sorghum, teff (the grain used to make Ethiopia's national bread, injera). Up to 400 species of these and other crops are housed here, 60,000 bags, each containing between 3,000 and 8,000 seeds from the same species and location. Ethiopia has retained the largest amount of traditional diversity of any country. Several of the crop varieties stored here are extinct in the fields and exist only within these walls, in one of the world's poorest countries, on the planet's most volatile continent.

In the lobby of the Addis gene bank is a life-size photograph of Nikolai Vavilov, the Russian botanist who in the early 20th century developed a landmark theory about the origins of cultivated crops. Gene banks tend to have a shrine to the man somewhere on the premises. The area where a crop has had the most time to evolve, Vavilov posited, will be the area where that crop contains the greatest breadth of genetic diversity, and therefore the area you'll want to visit if you're seeking a particular trait to breed into the plants. If, for instance, Ireland's genetically fragile potato crop is hit with a crushing blight, kicking off widespread famine, a gene for resistance would logically be found in the Andes, Vavilov reasoned, where the potato originated and where there are several thousand known varieties of the tubers.

Seeing Danger Luigi Guarino in Ethiopia

Today, crop scientists still rely on Vavilov's notion of "centers of diversity" and hail him as both a hero and a martyr. He spent his career crossing places like China, Bolivia and Abyssinia (modern-day Ethiopia) on foot, camel and donkey, gathering what was at that time the world's largest collection of seeds, both cultivated and wild, for conservation. The genetic diversity contained in those seeds, he believed, represented humanity's hope for survival. But politics got in the way of his work. Stalin wanted nothing to do with genetics, and Vavilov's progressive ideas amounted to heresy. In 1940, in his early 50s, Vavilov was jailed for pursuing "impractical science." Three years later, he starved to death in prison.

Vavilov wasn't the only Russian scientist who died in the name of crop diversity. During the 872-day Nazi blockade of Leningrad, Vavilov's colleagues holed up inside the gene bank he founded, determined to protect the seed collection from the Germans and the city's hungry residents. There, locked inside a building filled with seeds, roughly a dozen scientists died of starvation.

"The rice breeder literally died sitting at his desk with bags of rice," says Fowler, shaking his head. "I remember visiting the Vavilov Institute in 1985 and trying to understand what had gone on in this building that people would starve to death rather than eat food on their desks." He posed the question to a woman then connected to the Russian institute. "She looked at me quizzically and said, 'They were students of Vavilov.' As though that explained it all."

What it Takes To Be a Seed Hunter
Each seed gatherer involved with Svalbard is particularly passionate about plants from certain parts of the world. For Street, the Caucasus represents a potential goldmine of genetic diversity both because it's a Vavilov center of diversity (a "rich genetic soup") and because the Iron Curtain left the region essentially cut off from the West, so it's underrepresented in gene-bank collections. His current preoccupation is "plugging eco-geographic gaps": pinpointing areas where particular plants grow and might have interesting genetic variations but have not yet been collected.

One such gap in Street's CGIAR collection is the wild cousins of the chickpea, which happen to grow in very inhospitable areas. "Relatives of the chickpea are distributed in southeast Turkey"—bordering Iran and Iraq—"which is kind of dangerous," he says. "And then there's the bottom of the Caspian Sea in Iran, where it's difficult to get in because they're touchy about foreigners running around." When he heard rumors of wild chickpeas growing in the republic of Georgia, a highly unstable former Soviet territory-, he planned a trip to the region anyway. He describes it the way a CIA operative might: "The mission was targeted to grab these wild relatives."

Street's "missions" involve driving clunky old Russian jalopies through deserts or over mountain passes—wild and woolly lands where Kalashnikovs are common and where the police demand constant bribes, sometimes by force—to distant villages where camel's milk is plentiful but outsiders are rare. "We come in, and it's as if a UFO has landed," he says. "All these guys jump out of the trucks with their hats and cameras, and the villagers are like, 'Who are these dudes?' But they always offer hospitality, and vodka."

Debouck's work has sharpened his skills as a detective. In the 1980s, he was on the trail of gigantic lima beans that grow in Peru and Bolivia, kin to certain North American varieties. Conversations with farmers about the relative bitterness of their beans, images of beans painted on ancient pottery, and examinations of wild lima beans growing at the edges of farmers' fields combined to lead Debouck and his team to a discovery about the origins of lima beans. "We were able to provide the physical evidence that you had two domestication events for lima beans," he says proudly. "One in meso-America and one in the Andes."

Deep Storage North of mainland Norway, two security doors and three airlocks protect the cave's contents.

Debouck's bean collecting has taken him through the fields and forests of much of the Americas, scouring the ground in search of uncataloged species. He also combs the collections of the world's top herbaria. Several years ago, while rummaging through an herbarium in Paris, he stumbled on a misplaced specimen: a bean from North America lost in a box of woody plants from all over the world. "I realized that that plant was collected by a French explorer, exploring an area from Florida to the area that is today Quebec," he says. "It might even be a new bean species for the eastern United States."

He is currently tracking a wild bean that grows only in southern Florida. Luckily, one area is protected public land, making it possible that some of the wild plants still exist. But other bean populations grow on private land and are unlikely to survive any future development. "This," he says, "is the sort of race gene banks are in."

Far Afield Ken Street gathering wheat in Armenia

A Solvable Problem
Svalbard and its missionaries—Guarino, Street, Debouck, Fowler and the rest—are, in a sense, working to protect us from ourselves. "What's the biological basis for agriculture?" asks Steiner of the Gates Foundation. "It's in the diversity. Nature has been experimenting for millions of years, developing all these species designed for particular ecosystems. Agriculture is very local. At the end of the day, in most places monoculture isn't the most sustainable way."

Even Ethiopia's crops are now threatened by industrial farming. Tewolde Berhan Gebre Egziabher, the director general of Ethiopia's Environmental Protection Authority and a frequent representative for all of Africa on international treaties, believes his country is at a crossroads in terms of protecting its traditional crops. "Now that humanity has begun to learn of the loss of modernizing without protecting genetic resources," he says, "it's time not to make that mistake here."

"This is the only world problem we know we can solve at this point in history," Fowler agrees. "There's no clear solution for some things, like climate change, and the price tag [for that] is incredible. But for a rather limited amount of money, we can actually solve this one."

Despite the abundance found in the Addis market, much of Ethiopia lives on what Guarino calls "the knife edge." One bad year can be devastating. As he drives us back through the countryside south of the city, where donkeys are more plentiful than trees, he gestures around him. "Say someone gives them a hybrid crop, they grow it, and it does well for a few years," he says. We pass a group of barefoot boys, some wearing threadbare business suits over T-shirts, guiding ox plows across brown fields. "So now they've largely lost their old seeds, but then there's a drought or something and the new crop can't survive. And they've got nothing else."

Only a network of gene banks, with Svalbard as the backup, offers insurance against disaster. Vavilov's students believed their work was important enough to die for, Fowler points out. Svalbard is built in that spirit. "They thought the world was going up in flames," he says, "and this would be the seeds from which the world would be resurrected." 

The Skinny on the Environment

The Skinny on the Environment

The very structure of our communities may predispose us to inactivity and obesity. Now researchers are remodeling cities for healthier kids

 
Well-planned communities balance natural and artificial spaces.

When Susan Handy moved to Davis, Calif., in 2002, she immediately bought a commuting vehicle: a wheeled trailer, for toting her kids behind her bike. Handy, an environmental policy analyst at the University of California, and her husband frequently pedal to work, with two preschoolers in tow. Among locals, their commute is common. Fifty miles of bike lanes ribbon Davis, which is only about 10.5 square miles in area. Handy calls Davis “a small town that really works.”

City planners, health researchers and local leaders want more U.S. communities to “really work”—and to that end, they have begun retrofitting the country, from Atlanta to Sacramento. Inspired by a new urbanism that celebrates neighborhoods and alarmed by health problems—particularly childhood obesity—these trailblazers are building paths, sidewalks and other architectural features while promoting policies and behaviors that get people moving.

They have plenty to do. America’s metropolitan landscape is a fractured network of residential and industrial buildings, haphazardly decorated with green space. To get around in their “built environment,” or human-made surroundings, members of the average American household collectively logged more than 32,000 miles of car travel in 2001. According to National Household Travel Survey data, only 15 percent of children in the U.S. walk or bike to school—a 35 percent drop from three decades ago. At the same time, kids now spend an average of 44 hours a week sitting in front of a television, computer screen or other video monitor, according to a 2005 Kaiser Family Foundation study. Over the past five years, the study concludes, this “Generation M” (for media) has increased its total exposure by more than an hour each day, mostly by multitasking with different forms at once.

“Our built environment is a recipe for health problems, from obesity to asthma to depression,” says Richard Jackson, an adjunct professor of environmental health at the University of California, Berkeley. “Poor urban design has a distinct impact.” Childhood obesity, in particular, has become epidemic. Nearly a fifth of all children and adolescents in the U.S.—more than 12 million—are now overweight, according to the CDC’s National Center for Health Statistics. Can the U.S. redesign itself for a healthier future?

Trails to Fitness
Today’s built environments reflect decades of urban planning with a few consistent themes—cars and zoning, among them. The advent of America’s car culture in the 1950s inspired suburbs that sprawl, Handy points out. Reinforcing this trend, urban zoning requirements have frequently separated industrial or commercial settings and residential neighborhoods—partly in the interest of public health, to ensure that most homeowners do not live near polluting factories.

But this blueprint currently looks less benign. Pollution from nonfactory sources, such as smog from car tailpipes and lawn equipment, still fouls the air and contributes to asthma. Idle hours in the car spent traveling between residential and commercial destinations add up to inactivity. Even those who prefer to bike or walk often confront crowded roads and hectic intersections.

Rather than simply accepting this modern metropolis, early built-environment mavericks pushed for local change. On a sunny day in 1991, for instance, three cycling buddies in sprawling Atlanta together lamented the city’s polluted air and lack of bike trails. Then they got busy. The trio created the PATH foundation, a nonprofit whose mission is to develop a system of linked trails throughout metropolitan Atlanta.

Sixteen years later the PATH foundation has built 110 miles of trails in and around the city, through wetlands and nature preserves, along highways and across neighborhoods. The longest trail, dubbed the Silver Comet, stretches 57 miles from Atlanta to the Alabama state line. Built with a plan that combines public and private financing, all the trails are 12 feet wide, made of concrete and lined with maintained green space. PATH’s executive director, Ed McBrayer, calls the trails “linear parks.”

“We intend for all the trails to eventually link, like a transportation system, so people can use them to get to work, school, the gym and church,” McBrayer says. “We’re always building: two miles there and one mile here, on abandoned railroad tracks, wherever we have the money and the political will.” Although data on how the trails are used are limited, it is known that they inspire some exercise: in a January 2007 study by PATH foundation staff and Emory University researchers, sponsored by Georgia Healthcare Foundation, a third of 315 trail users surveyed at Davidson-Arabia Mountain Nature Preserve said that most of their weekly physical activity has involved the trails.

Similarly, a network of trails in the college town of Columbia, Mo., was born when educational technologist Ian Thomas and some friends calculated that the town of 75,000 included at least 60 residential streets lacking sidewalks. They founded the PedNet Coalition, now directed by Thomas, to lobby policymakers for pedestrian-friendly improvements and to promote activity to Columbia residents.

In 2004 PedNet convinced Columbia’s city council to revise its street design standards, adding or widening sidewalks, bike lanes and mixed-use paths. Those changes, in turn, helped the city win a $25-million grant from the Federal Highway Ad­ministration to build a comprehensive cycling and walking network. As part of the grant, Columbia will document how its efforts boost bicycling and walking, reduce traffic and energy use, and promote better health and a cleaner environment.

In fact, major changes in federal transportation policy are boosting built-environment projects nationwide. Spurred by local constituencies, lawmakers in 1991 and 1998 formally added bicycling and walking to transportation planning. As a result, bicycle and pedestrian projects—from sidewalks to bicycle lanes, trails and parking—now qualify for federal funds once dedicated exclusively to highways. Today states and metro areas are legally required to consider bicyclists and pedestrians in transportation plans. What’s more, a 2005 federal transportation bill allocated an additional $612 million for a new national Safe Routes to School program, requiring all states to hire a coordinator to administer funds to communities for new bike lanes, pathways, sidewalks, and education and promotion campaigns in elementary and middle schools.

Built-environment advocates agree that promotion—from generating political will to inspiring individual choice—is critical to their cause. Thomas points to school location as one example. “Because public schools are not seen as high priority, they are underfunded and thus buy the cheapest land available, on the edge of town,” Thomas explains. “How do you get your kids there? You have to drive.”

Even the support of neighbors isn’t guar­anteed. In Atlanta, McBrayer was surprised to discover that culture—not just cash—was an ­obstacle. “I initially assumed everyone wanted

to be connected,” McBrayer recalls. “And that’s not true. There are class and race issues, privacy issues and people who don’t want things to change.”

Adding to the challenge, Americans plainly enjoy their cars. In a 2005 study sponsored by the Southwest Region University Transportation Center, Handy and her colleagues interviewed Texas drivers to determine their routes to local destinations. They asked the question: How much of driving is determined by choice, rather than need? The answer: a significant amount. The study found that people often take extra trips, choose longer routes, pick more distant destinations and opt to drive rather than walk or bike.

Exercise physiologist Russell Pate of the University of South Carolina sees this tendency in his own community. “I live in a safe, relatively low traffic neighborhood with sidewalks that lead to a local elementary school,” Pate says. “Every morning there’s a line of SUVs half a mile long dropping off kids. The built environment is not the barrier there.”

Desperation Grows
Yet as the health-environment connection evolves into a national issue, foundations are stepping up to the challenge. This year the Robert Wood Johnson Foundation (RWJF), the largest U.S. philanthropy devoted to health, committed $500 million to fighting childhood obesity. Those funds will in part support three existing RWJF organizations—Active Living by Design, Active Living Research and Leadership for Healthy Communities—that seek to change policy, the environment and behavior to boost physical activity.

“There’s almost a desperation around the country to do something about childhood obesity,” says Active Living Research program director James Sallis, who is also a psychologist at San Diego State University. Active Living Research, in particular, is working to assemble evidence that the right built environments boost physical activity and improve health. “Increasingly, we plan to focus on funding peer-reviewed research that documents the most promising ways to reduce childhood obesity,” Sallis says.

In one of his own studies, published this past March in the American Journal of Health Promotion, Sallis collaborated with urban design specialist Lawrence Frank of the University of British Columbia and others to link Atlanta’s built environment with walking patterns in the city. Surveying more than 3,000 children and their parents, the researchers found that kids aged 12 to 15 were three times more likely to walk half a mile a day if a park, store or other popular destination were located within about 0.62 mile (one kilometer) of their homes. Overall, the team reported, children and families living in a “mixed-use” community—which offers destinations within walking distance—walk significantly more.

Walking half a mile may not sound like much exercise, but Pate puts it into perspective. He notes that preventing excess weight gain is likely to be easier than losing pounds. Furthermore, he says, most people pack on pounds gradually, because their day-to-day consumption of unburned calories is relatively small. Over time, for instance, 50 extra calories a day can cause someone to become overweight. And “a 10-year-old can burn more than 50 calories just walking to or from school or the park on a daily basis,” Pate points out.

Still, skeptics question how much sprawl is to blame for obesity. In a 2003 online editorial, the Heritage Foundation, a conservative think tank in Washington, D.C., argued that without more evidence, public policy should not require denser, mixed-use community designs. The foundation emphasized that data from the CDC on 445 counties showed few overall weight differences between communities designed differently. “For the country as a whole and comparing citizen weight in the 25 counties at either extreme of sprawl and compactness, 19.2 percent of residents in the least sprawling communities were obese, while 21.2 percent in the most sprawling were obese,” the editorial noted, calling such differences “trivial.”

Sallis has heard that argument before. “Most people would agree that there is not going to be a single solution to childhood obesity,” he responds. “We have to pursue many solutions. We have to make it harder to drive and easier to bike. We have to make it easier to find affordable, healthy food and harder to find junk food. We have to make it easier for kids to be active at school and after school. Obesity is a difficult problem to fix, but it’s certainly possible—and environment is a factor.”

In particular, Sallis continues, minority and low-income communities need new solutions. Studies have shown that these neighborhoods, on average, include fewer parks, more fast food outlets and more crime than affluent or Caucasian neighborhoods. Against this backdrop, these communities frequently suffer higher rates of obesity. Active Living Research plans to increase its support for reviews of these high-risk populations, Sallis says.

Other investigators are evaluating classic neighborhood designs. In northern California, Handy and her colleagues are studying cul-de-sacs, those horseshoe-shaped streets that typically dead-end at middle-class family homes dressed with basketball hoops, soccer nets and other sports paraphernalia. Seeking more “connectivity,” partly to promote walking and biking, city planners are increasingly outlawing cul-de-sacs in favor of streets laid out in a grid pattern.

But in a study presented at an Active Living Research Conference this past February, Handy’s team reported another side to the story. Across 27 households in Woodland, Calif., 75 percent of children living in cul-de-sacs reported being highly active outdoors, versus 55 percent of those residing on through streets. In a related survey of 1,672 parents, children ages five to 12 living in cul-de-sacs played outside more than four times in a given week, at least once more than those on through streets. “What’s the best neighborhood design for kids, and what’s the best for adults?” Handy asks. “The answer may not be simple.”

Elusive or not, the built environment is likely to become an even hotter topic of debate in years to come. For proof, Jackson points to his experience at U.C. Berkeley. “My students are as intensely invested in these issues as students were 30 years ago in the Vietnam War,” he says. “We’re going to retrofit communities to improve our health—and to improve our environment. These concerns are here to stay.”

5 New Year's Resolutions You Owe Yourself

5 New Year's Resolutions You Owe Yourself

We questioned health professionals and plumbed the scientific literature in a quest for the most life-enhancing New Year's resolutions possible

 

On New Year’s Day more than a few of us annually resolve to change our lives—or at least our more self-indulgent habits. On the hunch that all good things flow from physical and mental well-being, Scientific American Body offers this list of recommended resolutions based on the advice of health professionals and the scientific literature. Whatever your goals, it will help you understand why hardly anything you could choose to do would have a bigger impact on your quality of life.

Perhaps the best New Year’s resolution is coming up with a strategy to sensibly tackle each of the five listed below. “New Year’s resolutions are notoriously unsuccessful because people have a superficial commitment to them,” notes health psychologist Frederick Gibbons of Iowa State University. “Whatever behavior you want to change requires a specific plan for going about it.”

For instance, to quit smoking or to moderate drinking, “people might want to plan ahead for situations or cues they need to avoid, since they may face social pressure, even if it’s unintentional pressure. That might also include tempting foods,” Gibbons says. Social support is also critical. Warren Franke, director of Iowa State’s Exercise Clinic, believes that success toward an exercise or weight-loss goal could mean enlisting a significant other or a buddy to work out or diet with you or joining a formal program.

Controlling drinking may even require taking part in a behavior-modification treatment, Gibbons adds.

In pursuing these resolutions, set short-term goals, “such as losing just one pound a week,” Franke says. If you sometimes find yourself sliding, “such as trying that killer cheesecake, don’t feel bad about yourself and give up. Accept that was a bad day and that [the] next day will be a good day. And reward yourself. Life’s too short not to enjoy it. Don’t buy yourself six scoops of Ben & Jerry’s, mind you. I have a friend who, if she’s lost weight, buys herself People magazine. It’s a simple pleasure she enjoys, and it works.”

1. Stay Active
Exercising three times a week for about 30 minutes each session has been shown to cut cardiac morbidity and mortality by more than 10 percent, explains Seth Feltheimer, a general internist at New York–Presbyterian Hospital/Columbia University Medical Center.

To reap the maximum benefit from exercise, your pulse has to stay above 100 beats per minute. This requires more than an average walk, “where you might often stop and start at each corner and can’t really get a chance to get the pulse up,” Feltheimer adds. Franke agrees and recommends that you do whatever exercise you enjoy enough to do regularly and that is vigorous enough to increase your heart rate, be it walking with a neighbor or a high-intensity aerobics class at an exclusive fitness club.

“If you compare a person who is 30 pounds overweight but physically active with someone who is thin but a coach potato, you’ll find the thin couch potato has a higher risk of premature death and of some chronic diseases, such as diabetes, heart disease and hypertension,” Franke says. “Of course, the best combination is to be physically active and relatively close to normal weight, but if there was a choice, without hesitation I’d choose a little bit overweight but fit.”

2. Eat Healthy
Reducing cholesterol intake by 20 percent and getting total cholesterol levels below 180 will improve a person’s risk of heart disease by 20 to 30 percent, Feltheimer notes. Healthy diets should include at least five servings of fruits and vegetables a day, Franke declares. “This ensures that you get more vitamins and minerals, which most people don’t do, and will likely increase fiber intake as well,” he explains. “It will also be more filling, making you less likely to cheat and ingest more calories by nibbling on snacks.”

“It’s somewhat of a cliché, but the most important thing to do is to eat healthy and moderate your food intake,” Franke notes. Feltheimer concurs and offers a strategy to help with moderation: “Don’t eat until you can’t eat anything else. You should always leave the table feeling you can eat a little more.”

Moreover, as the experts note, many people’s downfall is that they think of diets as temporary impositions that they can drop once they have reached a goal weight. Rather a truly healthy approach to eating means making lifestyle and behavioral changes that last. So find a diet you can truly live with for the long haul.

3. Quit Smoking
It’s the advice you have probably been hearing for most, if not all, of your life. Yet despite the ubiquitous warnings, smoking is still the leading cause of preventable death in the U.S. The World Health Organization estimates that by 2015 tobacco will be responsible for 10 percent of all deaths—killing 50 percent more people than HIV will. Quitting smoking may be one of the most common New Year’s resolutions, but it is also easily one of the most valuable to keep.

Cigarette smoke contains 69 known carcinogens and increases risks for most forms of cancer, particularly of the lung, kidney, larynx, head, neck, bladder, esophagus, pancreas and stomach. Smoking also increases blood pressure and the risk of heart disease while decreasing the “good,” or HDL, cholesterol that lowers the risk of heart failure. The result is that every year, nearly 140,000 men and women in the U.S. die from cardiovascular disease attributed to smoking, according to the Centers for Disease Control and Prevention.

The financial costs are also considerable. At $7 a pack, a pack-a-day smoker is spending almost $50 a week and $2,600 a year—and that does not include any of the financial costs associated with the medical problems of smoking.

4. Drink Appropriately
Because of excessive drinking, which is defined as anything more than two drinks a day for men and one a day for women, over two million people in the U.S. have liver disease. Excessive drinking also increases the risk for heart disease, high blood pressure, stroke, inflammation of the pancreas and certain forms of cancer, especially cancers of the esophagus, mouth, throat, larynx and possibly the breast, colon and rectum.

Roughly 10 to 20 percent of heavy drinkers also develop alcoholic cirrhosis, or scarring of the liver; those with life-threatening cirrhosis may need liver transplants. In addition, Gibbons notes that statistics indicate “the more heavily you drink, the greater your risk for interpersonal problems.”

Yet studies suggest that moderate drinking— for men, two or fewer drinks a day, and for women, no more than one—lowers the risk for cardiac disease and death by heart attack or stroke.

By these measures, moderate drinkers fare better than both heavy drinkers and abstainers. Researchers believe moderate drinking helps to ward off cardiovascular disease by thinning the blood and thus suppressing the formation of blood clots that can cause heart attacks and strokes. Alcohol also seems to enhance the body’s ability to break down small clots.

5. Relieve Stress
“We’ve known for years that chronic stress leads to increased risk of premature death, even in the absence of other things it’s connected with, such as not taking care of yourself or high blood pressure,” Franke explains. Some of the physiological mechanisms are clear. “Stress leads to your body producing cytokines or other inflammatory agents. In chronic stress, you carry on such responses to an abnormal extent, past what the fight-or-flight response was perhaps meant to handle, wearing down the body.”

Furthermore, various studies have established that chronic stress can cause ex­cess­­ive blood clotting, leading to blockages and strokes, Felt­heimer says. “It also decreases the responsiveness of the immune system. And with chronic stress, some cytokines can in essence degrade the structural stability of plaques lining blood vessels, which is analogous to making a blister more prone to popping. So that can contribute to a heart attack if it does pop.”

“People need to focus on things that are within their control. It’s wasted energy to stress about what’s outside your control,” Franke says. “Try to downshift and go with the flow, and if there are situations you can’t downshift with, then avoid them if possible.”