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.”

The Ultimate Blood Test

The Ultimate Blood Test

A pricey way to determine health risks: 250 tests at once

 

As the dizziness began to fade and the nausea to subside, I kept thinking how two tablespoons did not sound like a lot of blood. During regular checkups, my physician draws only about half that amount. I suppose I might have guessed, especially after a 12-hour fast, I would sicken when my blood pressure and glucose levels dipped—I’m a terrible blood donor in that regard.

The nurse who drew my blood helpfully looked around my office for a sweet drink. “Do you have any soda or juice?” she asked. But the only thing I had was a can of Diet Coke. Which in a way is ironic: I used to drink regular Coke but switched to the sugar-free form after blood tests revealed that my triglycerides were too high.

Momentary ill feelings, though, were an acceptable physical price for 250 blood tests done at once—I was told that running them separately with conventional means would require a liter of blood. (Imagine how dizzy and nauseated I’d feel then.) So how could I not roll up my sleeve for Biophysical Corporation? The Austin, Tex.–based company promised to use the blood to screen for presymptomatic cancers, potential immune disorders, latent infections, undetected hormonal imbalances and unrecognized nutritional deficiencies. It seemed to mark a step toward that Star Trek future in which Dr. McCoy waves around a device shaped like a saltshaker to determine a person’s medical secrets. (“Heartbeat is all wrong. Body temperature is … Jim, this man is a Klingon!”)

The Biophysical250 assessment, as the firm calls it, is more than just a battery of tests. It includes a medical-history interview; a personal visit to the home or office for the blood draw (I should have picked my home, where I actually keep sugar); and a follow-up physician consultation. All this attention does not come cheap. It costs $3,400 and is not covered by health insurance. The company states that doing each test individually would cost 10 times more, so the Biophysical250 is a bargain by comparison. Still, you either need some disposable income or must be so indispensable to your employers that they will pay for it. I don’t fall into either category. But because I was reviewing its product, Biophysical agreed to conduct the test on me for free.

The analysis focuses on blood biomarkers, which are chemicals whose presence or amount may indicate abnormal processes or reactions in the body. Among the most familiar are cardiovascular ones: high- and low-density lipoproteins (HDL and LDL, the good and bad cholesterols) and triglycerides.

Checking 250 biomarkers at once might seem like overkill. A routine exam screens for two or three dozen. Looking at one biomarker in isolation, however, is usually not especially informative—for instance, the ratio of LDL to HDL is more important than either alone. The Biophysical250 takes it much further: to assess the risk for heart disease and stroke, the firm analyzes 33 biomarkers.

Examining several biomarkers together improves the odds of finding problems early, especially malignancies. Blood tests for cancers have been problematic, because healthy people may produce the same kinds and amounts of the biomarkers that cancer patients do. Moreover, the chemicals do not always show up in cancer patients, and they may result from unrelated conditions. The Biophysical250 screens for about four dozen blood chemicals tied to cancerous activity in general to increase the odds of detecting disease before symptoms appear.

For example, Biophysical points to ovarian cancer, which is usually diagnosed too late. Cancer antigen 125, the most commonly measured marker for the disease, shows up in only half of patients in stage 1, when treatment is most likely to succeed. The Biophysical250 tries to boost the chance of early detection by measuring other, biologically independent compounds, such as vascular endothelial growth factor, interleukin-6 and monocyte chemoattractant protein.

Testosterone's Bad Rep

Testosterone's Bad Rep

Hormones don't necessarily make men violent, but they do cause them to seek social dominance 

Professional wrestler Chris Benoit’s powerful build and muscular grappling maneuvers helped to make him a crowd favorite and propelled him to a world heavyweight championship in 2004. No one was prepared for the shocking turn this past June when he killed his wife and son, then hanged himself in their home near Atlanta. The subsequent announcement by the state medical examiner’s office that Benoit’s body showed he had been taking injections of testosterone (along with an antianxiety drug and a painkiller) seemed all too predictable, given how often anabolic steroids such as testosterone have been linked to violent behavior.

And yet the official findings might still have offered one surprise: according to medical examiner Kris ­Sperry, there was no clear evidence that the steroids played a part in the murders. Benoit’s levels of testosterone were 10 times normal, but as Sperry was quoted as pointing out, “An elevation of that ratio does not translate into something abnormal in a person’s thought process or behavior.”

It’s commonly assumed that testosterone, that stereotypically male hormone, is intimately tied to violence. The evidence is all around us: weight lifters who overdose on anabolic steroids experience “roid rage,” and castration—the removal of the main source of testosterone—has been a staple of animal husbandry for centuries.

But what is the nature of that relationship? If you give a normal man a shot of testosterone, will he turn into the Incredible Hulk? And do violent men have higher levels of testosterone than their more docile peers?

Historically, scientists had assumed the answer was yes, but the truth has proved more complex. “Researchers expected an increase in testosterone levels to inevitably lead to more aggression, and this didn’t reliably occur,” says Frank T. McAndrew, a professor of psychology at Knox College in Galesburg, Ill. Indeed, recent research about testosterone and aggression finds only a weak connection between the two. And when aggression is more narrowly defined as simple physical violence, the connection all but disappears.

“What psychologists and psychiatrists say is that testosterone has a facilitative effect on aggression,” comments Melvin J. Konner, an anthropologist at Emory University and author of The Tangled Wing: Biological Constraints on the Human Spirit (Owl, 2003). “You don’t have a push-pull, click-click relationship where you inject testosterone and get aggressiveness.”

Instead what emerges from experiments with surgical and medical castration is a more complex pattern of cause and effect. Testosterone may be necessary for enabling violent behavior, but it is not, on its own, sufficient. In that sense, testosterone is less a perpetrator and more an accomplice—one that is sometimes not too far from the scene of the crime.

In both men’s and women’s prisons, for example, the most violent inmates have higher levels of testosterone than their less violent peers. Yet scientists hypothesize that this violence is just one manifestation of the much more biologically and reproductively salient goal of dominance.

“It has been suggested that the antisocial behaviors related to high testosterone are a function of the manner by which dominance is maintained in these groups,” says psychologist Robert Josephs of the University of Texas at Austin. In other words, if researchers were to study other groups of folks—say, the rich and famous—they might discover that testosterone is connected not to violence but to the person who drives the biggest SUV or has the nicest lawn. As Josephs puts it: “Slipping a shiv into your neighbor’s back might play in the penitentiary, but it probably won’t earn you any status points in Grosse Pointe.”

The late psychologist James M. Dabbs made a career out of conducting studies connecting testosterone to every kind of lifestyle imaginable. In his book Heroes, Rogues and Lovers (McGraw-Hill, 2001), co-authored with Mary Godwin Dabbs, he notes that athletes, actors, blue-collar workers and con artists tend to have higher levels of testosterone than clerks, intellectuals and administrators.

Biodiesel Takes to the Sky

Biodiesel Takes to the Sky

An unmodified Czechoslovakian jet flew burning nothing but cooking oil 

 
FRYING FUEL: BioJet 1 flew for 37 minutes with only pure cooking oil in its engines.

Biodiesel may not become the airplane fuel of the future but it did prove effective enough to recently power a 1968 L-29 Czechoslovakian jet—dubbed BioJet 1—up to 17,000 feet (5,180 meters) over 37 minutes. A three minute, 15-second test the day before was the world's first flight entirely fueled by cooking oil.

"She flew and she flew just fine," says physicist Rudi Wiedemann, president and CEO of Biodiesel Solutions, Inc., whose company provided the fuel for the historic October flight: fresh canola oil refined into biodiesel. "We wanted to show that it was doable by just going out and doing it."

Specifically, Doug Rodante, president of Green Flight International (a company in Florida that promotes alternative aviation fuels), and chief test pilot Carol Sugars, a senior pilot with the United Parcel Service (UPS), conducted extensive fuel tests on the ground, beginning with a 20 percent blend of biodiesel and normal jet fuel (kerosene known as Jet A) and progressing to 100 percent biodiesel (B100) as their confidence increased.

Revolutions per minute in the engine on B100 were at 98 percent, Rodante notes. "We didn't get full power, but we got an acceptable amount" he says. "It was a nonissue in climb performance and time to altitude."

The L-29 jet (acquired from the Ukrainian military) is one of the few planes capable of burning biodiesel at present, thanks to a built-in fuel warming system. Biodiesel can gel at cooler temperatures, such as those experienced on a winter's day or at high altitude. "Jet fuel and biofuel mix is something that is easily done. I don't believe 100 percent biofuel is the answer," Rodante says. "We can implement a 20 percent mix with no modifications in other aircraft."

Such a blend would offer significant environmental benefit—most notably reduced emissions of carbon dioxide, the most common greenhouse gas. "As little as 20 percent biodiesel in petroleum diesel fuel will reduce carbon emissions by 50 percent," Wiedemann says. Airplanes emit roughly 12 percent of the man-made greenhouse gas emissions from transportation, but they are among the fastest growing sources and, potentially, the most damaging because of their release higher in the atmosphere. And the U.S. Air Force has been evaluating alternative fuels, including biofuels from animal fats, going so far as to certify the B-52 bomber to burn such synthetic fuels.

The Green Flight team is currently evaluating the exact emissions of the biodiesel burning as well as how it affected the various seals and rings in the L-29's jet engines. Until the latter testing is wrapped up and Biojet 1's safety is confirmed, the Federal Aviation Administration has grounded the plane. But Rodante says the evaluations could be completed within the next few weeks, after which he plans to fly the experimental jet from Reno, Nev., to Orlando, Fla.—the first transcontinental biodiesel flight, in eight stops. And, eventually, he hopes to fly a similarly fuelled plane around the world. "Aviation emissions are something that needs to be addressed," he says. "We're not moving fast enough."

Why do parrots have the ability to mimic?

Why do parrots have the ability to mimic? 

Parrots are not equally vocal, and many species likely imitate for different reasons. For example, African grey parrots in the wild are known to imitate other species of birds. My own observations of Amazon parrots from Mexico to Guyana to Peru revealed only imitations of each parrot's own species (and their own local dialects). When parrots are kept as pets, they learn their calls from their adoptive human social partners. Part of their appeal as pets is their ability to sing lower notes than smaller birds and so better reproduce human voices. In the wild, though, their calls may go much higher in pitch and much faster in tempo than any human tutor's voice. Regrettably, our desire for pet parrots has led to population declines of many species in their wild habitats.

But why do parrots and other birds rely on learning for vocal development instead of having each call developmentally hardwired, as with many other birds and animals? Some benefits of learning may include development of context-specific calls. Imitative vocal learning is also a reliable social display of neural functions—requiring good hearing, memory and muscle control for sound production—that may be under consideration by a potential mate or ally.

One consequence of vocal imitation is that local dialects can arise. In some cases, these regional calls may help males and females from similar areas find each other—or perhaps avoid each other. Song learning in some bird species allows territorial neighbors to know each other and helps to distinguish drifters from local territory holders. In an experimental captive population of budgerigars (small parrots from Australia, often referred to as parakeets), contact calls converged in a seeming adoption of a clan label. One study reports that budgerigars seemed to use call similarity in judging mates.

Playback studies of geographic dialects from wild parrot populations have shown that birds react more strongly to their local tongue. Maybe this is the best reason for these parrots to imitate: to better command the attention of a potential listener by producing sounds for which the listener already has a memory (or a "neural template"). The existence of a preformed perceptual template in the listener makes another parrot's imitations of him or her easier to perceive in a noisy environment. Imitations may even be directed to specific intended receivers.

Parrots, however, are not the only birds that learn by imitation. Indian mynah birds are also famed for their imitative capabilities, and in the U.S., northern mockingbirds sing repeated phrases with bits of calls appropriated from blue jays, robins, cardinals and other birds. These utterances are used in the springtime displays that inspired their common name as well as their scientific one: Mimus polyglottus.

The comparative study of parrots, and other vocally imitative animals, will help us to understand how evolution shapes neural mechanisms for complex social communication. Sadly, habitat loss and capture for the pet trade have pushed many parrot species to the brink of extinction. Parrots' great facility for learning (and the dialect variation it produces) underscores the need to save endangered species as whole populations, with their historically informative vocal traditions intact.