Passage One

(1) There are more than 300 million of us in the United States, and sometimes it seems like we’re all friends on Facebook. But the sad truth is that Americans are lonelier than ever. Between 1985 and 2004,the number of people who said there was no one to discuss important matters with tripled, to 25 percent, according to Duke University researchers. Unfortunately, as a new study linking women to increased risk of heart disease shows, all this loneliness can be detrimental to our health.

(2) The bad news doesn’t just affect women. Social isolation in all adults has been linked to a raft of physical and mental ailments, including sleep disorders, high blood pressure, and an increased risk of depression and suicide. How lonely you feel today actually predicts how well you’ll sleep tonight and how depressed you’ll feel a year from now, says John T. Cacioppo, a neuroscientist at the University of Chicago and coauthor of Loneliness: Human Nature and the Need for Social Connection. Studies have shown that loneliness can cause stress levels to rise and can weaken the immune system. Lonely people also tend to have less healthy lifestyles, drinking more alcohol, eating more fattening food, and exercising less than those who are not lonely.

(3) Though more Americans than ever are living alone (25 percent of U. S. households, up from 7 percent in 1940) ,the connection between single-living and loneliness is in fact quite weak. “Some of the most profound loneliness can happen when other people are present,” says Harry Reis, professor of psychology at the University of Rochester. Take college freshmen: even though they’re surrounded by people almost all the time, many feel incredibly isolated during the first quarter of the school year with their friends and family members far away, Cacioppo says. Studies have shown that how lonely freshmen will feel can be predicted by how many miles they are from home. By the second quarter, however, most freshmen have found social replacements for their high-school friends. Unfortunately,as we age, it becomes more difficult to recreate those social relationships. And that can be a big problem as America becomes a more transient society, with an increasing number of Americans who say that they’re willing to move away from home for a job.

(4) Loneliness can be relative: it has been defined as an aversive emotional response to a perceived discrepancy between a person’s desired levels of social interaction and the contact they’re actually receiving. People tend to measure themselves against others, feeling particularly alone in communities where social connection is the norm. That’s why collectivist cultures, like those in Southern Europe, have higher levels of loneliness than individualist cultures, Cacioppo says. For the same reason, isolated individuals feel most acutely alone on holidays like Christmas Eve or Thanksgiving, when most people are surrounded by family and friends.

(5) Still, loneliness is a natural biological signal that we all have. Indeed, loneliness serves an adaptive purpose, making us protect and care for one another. Loneliness essentially puts the brain on high alert, encouraging us not to eat leftovers from the refrigerator but to call a friend and eat out. Certain situational factors can trigger loneliness, but long-term feelings of emptiness and isolation are partly genetic, Cacioppo says. What’s inherited is not loneliness itself, but rather sensitivity to disconnection.

(6) Social-networking sites like Facebook and MySpace may provide people with a false sense of connection that ultimately increases loneliness in people who feel alone. These sites should serve as a supplement, but not replacement for face-to-face interaction, Cacioppo says. He compares connecting on a Website to eating celery: It feels good immediately, but it doesn’t give you the same sustenance. For people who feel satisfied and loved in their day-to-day life, social media can be a reassuring extension. For those who are already lonely, Facebook status updates are just a lernindei of how much better everyone else is at making friends and having fun.

(7) Michael J. Bugeja, a professor of communications at Iowa State University and author of Interpersonal Divide: The Search for Community in a Technological Age, says that the encroachment of digital communication into our social lives can amplify feelings of isolation.

(8) According to Cacioppo, there’s no magic number for the number of friends you need to avoid loneliness. An introvert might need one confidante not to feel lonely, whereas an extrovert might require two, three, or four bosom buddies. Experts say it’s not the quantity of social relationships but the quality that really matters. “The most popular kid in school may still feel lonely,” Cacioppo says. “There are a lot of stars who have been idols and lived lonely lives.”

Passage Two

(1) In the post-Silent Spring 1960s, when the pesticide DDT was discovered to be toxic to humans and wildlife and to persist for years in the environment, farmers and landscapers turned enthusiastically to Methoxychlor (甲氧氯 ). The pesticide—also commercially known as Chemform, Methoxo, Metox or Moxie—had a much shorter half-life and was billed as the safe alternative to DDT. Now, new research argues that exposure to the pesticide could cause diseases three generations later, in offspring who were never exposed to the Methoxychlor themselves. Biologist Michael Skinner and his team at Washington State University found that if a rat fetus is exposed to Methoxychlor during the first trimester (三个月) of pregnancy, the likelihood of kidney disease, ovary (卵巢) disease and obesity in their progeny (后裔) was elevated for three generations. Multiple diseases were even more prevalent in the third generation than in the second. In other words, Methoxychlor, which was banned in the U.S. in 2003 for a host of human health reasons, can still leave its mark on a population decades after exposure ends. The great-greatgrandchildren of a woman exposed to Methoxychlor may still be suffering the consequences. The new finding follows Skinner’s previous research, which identified transgenerational epigenetic (遗传的) disorders resulting from toxins including PCBs and DEET through up to six generations. Epigenetics govern which genes turn on and off and when, so epigenetic “misbehavior” can lead to a range of diseases, especially obesity and diseases that affect the reproductive system and kidneys. In the majority of Skinner’s previous findings, the problem was identified as altered epigenetics in the sperm. In the Methoxychlor, it was the egg that contained the damaged “epigenetic signature” resulting in susceptibility to disease passed generationally through the mother.

(2) Methoxychlor was banned after it was found to mimic estrogen (雌激素), acting as a reproductive toxin leading to infertility in animals. It turned up in human breast milk, and it is assumed to be able to cross the placenta (胎盘). In high doses, it can act as a neurotoxin, damaging an animal’s nervous system. While those hazards would affect the first generation exposed, the epigenetic mutations that result from transgenerational inheritance can cause entirely different diseases. “If the sperm or the egg has an altered epigenetic signature that is being used to develop the early embryo (胚胎), those signatures are transferred to the embryonic stem cell, which can turn into any cell in the body. Because of the altered epigenetics, every cell in the body will have an altered expression of genes, and therefore so will every tissue,” Skinner explained. “If the tissue is a type that is sensitive to small changes, to what genes are turned off and on, it will be susceptible later in life to disease. “For example, the adipose (脂肪的) tissue determines to a large degree how your body stores fat. Adipose is highly sensitive to epigenetic changes, like the kind that Sk inner argues can be triggered by a great-grandmother’s exposure to Methoxychlor. If your adipose tissue is out of whack, even a small amount of caloric intake will be converted to fat, leading to obesity.

(3) The EU banned Methoxychlor in 2002, and the US followed suit in 2003. But that doesn’t mean it immediately left the country’s food and water supply—a ban only ends production of the chemical, but any privately owned stocks of the chemical can still be in use, so banned chemicals can take years to be fully phased out. For example, the Environmental Working Group found above-threshold levels of Methoxychlor in some municipal water supplies in Iowa after 2004. While most developed nations have banned Methoxychlor, Skinner says the pesticide is still widely used in Mexico and in South American countries, where the US gets a significant portion of its produce. Mexico is the second largest provider of agricultural products to the US. “If we get our food from places in South America and Mexico, that’s of concern,” Skinner says.

Passage Three

(1) We live in a stressful era. Our lives are stressed, our cities are stressed, and our overscheduled children are stressed. There’s even a new term—”second-hand stress” —to describe how stress can be passed on to others as if it were contagious. In many ways, you can blame technology—it’s making our lives faster, busier and more complicated. So, it’s comforting that technology innovators in fields ranging from mobile technology to neuroscience are rethinking how we monitor, treat and yes, reverse the impact of stress in our lives.

(2) You probably think of your smartphone as a source of stress, rather than as a way to combat stress. To counter that perception, mobile innovators started by launching a round of apps for iOS and Android that promised to help users reduce the level of stress and anxiety in their lives. Some of these apps were nothing more than meditation timers, guides to breathing exercises or a selection of relaxing melodies. Others, though, such as the Huffington Post’s GPS for the Soul, offered a preview of how factors such as heart rate could be monitored by your smartphone to help you de-stress. Now that Google and Apple are jumping into the digital health game, you can understand what might become the new goal for app developers—a “stress app” that will help people not only deal with stress in their lives, but also monitor, measure and track it on their smartphones. One of the latest prospects is a smartphone tool that measures the level of the stress hormone Cortisol (皮质醇) content in your saliva. Using a disposable test strip for saliva in combination with a smartphone, users might one day be able to get a readout of their stress levels within 10 minutes at minimal cost.

(3) Those saliva tests conducted with the help of our smartphones hint at what’s next—biosensors (生物传感器) implanted within our bodies that relay information about our body’s reaction to environmental stressors on a²⁴⁄₇basis. For example, DARPA is currently developing biosensors for one of the most stressful environments around— the battlefield. Soldiers with these embedded biosensors would be able to provide military leaders with real-time readouts of stress levels or other factors that impact battle readiness. It’s easy to see how these biosensors could be adapted for civilian purposes, now that the wearable technology trend appears to be taking off. At this year’s CES in Las Vegas, for example, one of the innovations on display was the Muse brainwave sensing headband. In the future, sensors could detect signs of stressors being released by the body in addition to the brain’s activity.

(4) At the end of the day, stress is really just the human body’s physical response to the surrounding environment. So, it’s only natural that some people simply have better genetics than others when it comes to managing and dealing with stress. Given our expanding knowledge of the human genome, it’s worth considering how some bodily functions could actually be altered at the genetic level to make anyone less receptive to stress in the workplace or home. Imagine your body producing less adrenalin (肾上腺素) and less Cortisol, and thereby registering less anxiety. Think of your palms and forehead not dripping with sweat the next time a stressful environment presents itself.

(5) We’ve all heard how stress impacts the brain, so it’s no wonder that neuroscience is emerging as a prospective way of dealing with stress. In the best-case scenario, in fact, neuroscientists might be able to reverse—or at least, negate—the impact of stress on the brain. Here’s where it gets interesting—neuroscience is one of the windows into stress at a very young age. So, in an era when kids are overscheduled and overstressed, this might be a way to hit stress at an early age—before stress has time to aggregate over time and cause other impacts. For now, most of the suggestions from the realm of neuroscience sound more like conventional folk wisdom—let the little ones get more exercise—but once we’ve finished mapping the human brain, it’s easy to see how we might discover how stress impacts the brain’s neural pathways in other ways.

(6) At the end of the day, though, one of the breakthrough innovations when it comes to living a stress-free life might simply be changing the way we think about stress. As Kelly McGonigal explained at TED Global last year, it’s not necessarily the case that stress is the enemy. Stress, it turns out, can also be your friend. That’s a subtle but important point. Evolution equipped our bodies with stress responses—and some of them—like the release of oxytocin (催产素)—might actually be channeled in ways that make our lives better and enjoyable. One day, we might actually eat stress for breakfast and enjoy it.

Passage One

Passage Two

Passage Three