Obesity is an epidemic to some and an opportunity to others. More than two-thirds of Americans are overweight. Find a way to battle obesity,【C1】_____a huge profit might be made. On February 22nd, 2013 one pharmaceutical firm, Vivus, took a small【C2】__towards this goal. A committee advising America’s Food and Drug Administration (FDA) recommended Vivus’s diet drug, Qnexa.【C3】__, the pill’s long-awaited final approval may not come until April. The announcement mostly served as a reminder of a struggle which【C4】_____fat into gold.

Medical-device and pharmaceutical companies are quite【C5】_____treating the problems that come with obesity. However, they can’t help consumers【C6】__weight. Allergan, a device-maker, has tried to use its gastric bands to enter the obesity market. The band is fitted near the top of patients’ stomach, which helps them feel full【C7】__during the meal. Allergan has captured about 70％ of the worldwide market for gastric bands, but sales are now【C8】__. The recession has sapped consumers’ desire for expensive surgery. Some patients have【C9】__bands removed because they slipped or proved【C10】__. In January David Pyott, Allergan’s chief executive, said he would cancel an effort to market the band for teenagers. He is now trying to convince insurers of the gastric band’s【C11】_____.

Drug companies have had even more【C12】_____than device-makers. It has been 13 years since the FDA approved a【C13】__diet pill. That drug, Roche’s Xenical, has【C14】__side-effects. The FDA rejected Vivus’s Qnexa in 2010 over【C15】_____for the safety of pregnant women and the quickening of patients’ heart rates. However, Vivus’s new data in 2013 apparently satisfied the FDA’s advisory committee.

But the agency may yet【C16】_____the drug.【C17】__Qnexa is approved, it is unclear that patients will buy it. Qnexa【C18】__two medicines that are already on the market. Both medicines are generic, which means that doctors may【C19】__the existing drugs rather than Qnexa’s more expressive version. For now, it is more【C20】_____to treat fat patients than to try to make them slim.

Psychologists have known for a long time that economists are wrong. Most economists—at least, those of the classical persuasion—believe that any financial gain, however small, is worth having. But psychologists know this is not true. They know because of the ultimatum game, the outcome of which is often the rejection of free money.

In this game, one player divides a pot of money between himself and another. The other then chooses whether to accept the offer. If he rejects it, neither player benefits. And despite the instincts of classical economics, a stingy offer (one that is less than about a quarter of the total) is, indeed, usually rejected. The question is, why?

One explanation of the rejectionist strategy is that human psychology is adapted for repeated interactions rather than one-off trades.In this case, taking a tough, if self-sacrificial, line at the beginning pays dividends in future rounds of the game. Rejecting a stingy offer in a one-off game is thus just a single move in a larger strategy. And indeed, when one-off ultimatum games are played by trained economists, who know all this, they do tend to accept stingy offers more often than other people would. But even they have their limits. To throw some light on why those limits exist, Terence Burnham of Harvard University recently gathered a group of students of microeconomics and asked them to play the ultimatum game. All of the students he recruited were men.

Dr. Burnham’s research budget ran to a bunch of $40 games. When there are many rounds in the ultimatum game, players learn to split the money more or less equally. But Dr. Burnham was interested in a game of only one round. In this game, which the players knew in advance was final and could thus not affect future outcomes, proposers could choose only between offering the other player $25 (i.e., more than half the total) or $5. Responders could accept or reject the offer as usual. Those results recorded, Dr. Burnham took saliva samples from all the students and compared the testosterone levels assessed from those samples with decisions made in the one-round game.

As he describes in the Proceedings of the Royal Society, the responders who rejected a low final offer had an average testosterone level more than 50％ higher than the average of those who accepted. Five of the seven men with the highest testosterone levels in the study rejected a $5 ultimate offer but only one of the 19 others made the same decision.

What Dr. Burnham’s result supports is a much deeper rejection of the tenets of classical economics than one based on a slight mis-evolution of negotiating skills. It backs the idea that what people really strive for is relative rather than absolute prosperity. They would rather accept less themselves than see a rival get ahead. That is likely be particularly true in individuals with high testosterone levels, since that hormone is correlated with social dominance in many species.

Economists often refer to this sort of behaviour as irrational. In fact, it is not. It is simply, as it were, differently rational. The things that money can buy are merely means to an end-social status-that brings desirable reproductive opportunities. If another route brings that status more directly, money is irrelevant.

The humble but industrious ant has long served as a metaphor for the economic virtues of simplicity, parsimony and diligence. But in the case of weaver ants in Africa, this description may be more than just a metaphor. According to Paul Van Mele of the Consultative Group on International Agricultural Research and his colleagues, African mango farmers could increase their harvests by as much as two-thirds with the help of these doughty insects.

Mangoes in Africa, as elsewhere, often fall prey to fruit flies, which destroy about 40％ of the continent’s crop. In fact, fruit flies are so common in African mangoes that America has banned their import altogether, to protect its own orchards. African farmers, meanwhile, have few practical means to defend their fruit. Chemical pesticides are expensive. And even for those who can afford them they are not that effective since, by the time a farmer spots aninfestation, it is too late to spray. Added to that, spraying tall trees is a much more complicated and unhealthy business than treating low-growing fruit and vegetables.

Agricultural scientists have also looked at controlling fruit flies with parasitic wasps. But the most common ones kill off only about one fly in 20, leaving plenty of survivors to go on the rampage. Lethal traps baited with fly-attracting pheromones are another option. But they, too, are expensive. Moreover, all these methods require farmers to detect the presence of fruit flies, and to identify them as the main threat to their crop—no mean feat when most of the action is taking place in dense, leafy canopies ten metres off the ground. Instead, most farmers simply harvest their fruit early, when it is not yet fully ripe. This makes it less vulnerable to the flies, but also less valuable.

Farmers whose trees are teeming with weaver ants, however, do not need to bother with any of this. In a survey of several orchards in Benin, Dr. Van Mele and his colleagues found an average of less than one fruit-fly pupa in each batch of 30 mangoes from trees where weaver ants were abundant, but an average of 77 pupae in batches from trees without weaver ants. The weaver ants, it turns out, are very thorough about hunting down and eating fruit flies, as well as a host of other pests. The only drawback is the ants’ painful bite, which can be avoided by harvesting fruit with poles, rather than climbing trees.

Weaver ants have been used for pest control in China and other Asian countries for centuries. The practice has also been adopted in Australia. But Dr. Van Mele argues that it is particularly suited to Africa since weaver ants are endemic to the mango-growing regions of the continent, and little training or capital is needed to put them to work. All you need do is to locate a suitable nest and run strings from it to the trees you wish to protect. The ants will then quickly find their way to the target. Teaching a group of farmers in Burkina Faso to use weaver ants in this way took just a day. Those farmers no longer use pesticides to control fruit flies, and so are able to market their mangoes as organic to eager European consumers, vastly increasing their income. The ants, so to speak, are on the march.

As the oil price climbed towards $100 a barrel during the past few weeks, big Western oil firms were reporting their results for the third quarter. Record oil prices, it turns out, do not translate into record profits. Oil is now close to exceeding the record set in 1979 of between $100 and $110, depending on how you adjust for inflation and what benchmark you use. Yet almost without exception, big oil firms’ profits are falling from the peaks reached last year.

Exxon Mobil, for example, reported a 10％ drop in profits in the third quarter, and BP’s fell even more sharply. Profits also fell at Chevron, ConocoPhillips and Eni. They rose at Total and Royal Dutch Shell—but only thanks to exchange-rate fluctuations and one-off asset sales. Analysts at Citigroup calculate that, measured in dollars, the biggest oil firms’ earnings fell by 15％ on average.

To be fair, the oil price has surged most dramatically since the end of September, although it was also buoyant in the third quarter. The majors’ poor showing also reflects lower profits from refining, as the difference in price between petrol and crude oil has fallen from the exceptionally high levels of recent months.

But the fact remains that oil giants are struggling to pump more oil and gas. In part, this is due to a quirk of the rules that oblige Western oil firms to share the crude they produce with state-owned oil firms in many countries. The contracts in question often stipulate that as the price goes up, the volume of oil the foreigners receive decreases. Worse, several countries are changing contracts or tax rules in ways that will further erode the Western oil firms’ profits—and in some cases are throwing them out altogether.

Rising costs are also a problem. Exxon, which is known for its stringent financial discipline, saw costs rise almost twice as fast as revenue in the third quarter. The shortage of labour and equipment that is feedingthis inflationis also causing delays to new projects. And there are not enough new projects in the pipeline. The International Energy Agency reckons that the expansion plans of the big Western and state-owned oil firms will leave the world 12.5m barrels per day short of requirements in 2015.

Despite thisloomingdeficit and the glaring price signal, all the big companies except Total produced less oil and gas in the third quarter than they did in the same period last year. According to Citigroup, the average decline in overall output was 3.3％. If the relatively steady supply of natural gas is stripped out, the numbers look even worse: Oil production fell by 9％ on average. No matter how high the price goes, the oil majors cannot make a profit from oil they do not produce.

Kids heading back to enlightened schools this fall may find nutrition and exercise on the agenda even in math class. In an effort to reverse the alarming increase of obesity in children, some schools have found ways to encourage healthful lifestyle changes without emphasizing the negative-too much body weight. Planet Health, developed by Harvard University researchers and now used in hundreds of schools throughout the country, integrates obesity prevention lessons into the science, math, and social studies curricula, for example. Students come to appreciate the importance of reducing TV time by calculating during math class the amount of their lifetime they’ve spent in front of the set. In gym, they decide on goals for subbing in physical activity instead.

The program costs only about $15 per student annually, a bargain, considering the payoffs: A 2005 study published in the Archives of Pediatric and Adolescent Medicine found that middle-school girls who had Planet Health in their schools were half as likely to purge or use diet pills as those in schools without it. “It really focuses on the positive, and that’s why we think it’s protective against these dangerous behaviors,” says study author Bryn Austin, an assistant professor of pediatrics at Harvard Medical School.

A second program adopted by 7,000 elementary schools nationwide, the Coordinated Approach to Child Health (CATCH), similarly puts the focus on good health habits instead of weight. In class, students use a traffic-light system to identify “go”, “slow”, and “whoa” foods and take breaks to do jumping jacks. In the cafeteria, fruits, vegetables, low-fat milk, and whole-grain starches are labeled with green-light tags, and pizza gets a yellow light. Gym activities are designed to keep students constantly moving. “Every kid gets a ball to dribble or a hula hoop; there’s no lining up and waiting to take a turn.” says Phil Nader, professor of pediatrics emeritus at the University of California—San Diego, who helped develop CATCH.

A three-year study comparing CATCH schools with others without the program found that CATCH increased the proportion of gym class spent in motion, from 40 percent to 50 percent, and reduced the consumption of fat in schools from 39 percent of total calories to 32 percent. A second study found that the program prevented the growth in number of overweight students that normally occurs from grade 3 to grade 5. CATCH students in El Paso, Texas (with one of the highest obesity rates in the nation), held the line between those grades, but in schools without the program, the share of overweight girls increased from 26 percent to 40 percent and of overweight boys from 29 percent to 39 percent.

Glen Cove Elementary School, near EI Paso in Ysleta, was one of the first schools to adopt CATCH, and parents there have learned to eat better and exercise more along with their kids. “We have a day where everyone comes to fly kites and Wellness Wednesdays where family members run around for 20 minutes with their kids,” says physical education teacher Ben Avalos, who brought the program to Glen Cove in 1998. “Parents also tell me their kids have gotten them to throw out the ’whoa’ foods in the house.” Avalos uses walking sticks, pogo sticks, and Chinese yo-yos in gym class—and nobody relaxes on the sidelines.

[A] Suggest a pre-interview.

[B] How do you know your contact.

[C] Leave enough time to your referrer.

[D] Understand your contact’s position in the company.

[E] Put your request in writing.

[F] Is your contact willing to provide a referral.

[G] Say “thank you”.

Whether you’re unemployed or supported by a regular paycheck, job hunting and blindly sending out resumes can be a tiring and frustrating experience. So when the career gods smile in your direction and provide your dream position at a company where you know an employee, it can feel as though your professional traffic jam just opened onto the six-lane new-job freeway. But before you fire off that “Will you refer me?” email, consider some of these important factors that can make or break your chances at an interview.

【R1】________

If your intended referrer is your best college pal or Aunt Winnie, proceed with caution. While it’s great to have friends or family who can vouch for you on a personal level, many hiring managers are more interested in your professional abilities. And getting a referral from someone who can’t even repeat what you do for a living may come across as a weak attempt at getting your foot in the door, not a strong recommendation. The best contact is one who knows your career progression and accomplishments.

【R2】________

Your dream job resides in sales and marketing, but your contact at the company works in tech support. At small companies, this link may be sufficient enough to secure you an interview, but you can’t always count on it. The best referral will come from someone who is knowledgeable about the open position and the kind of requirements and experience it entails.

【R3】________

If you decide that your contact is a strong one, then make your request in writing. Your potential referrer can then take the time to thoughtfully consider whether or not she is comfortable making an introduction before responding to you with her answer. And you give her a chance to quickly research any pertinent information regarding the hiring manager and job qualifications.

【R4】________

When making your referral request, ask your contact whether she is comfortable providing a referral. While you might be eager to cut to the chase by asking directly for an endorsement, a wishy-washy or noncommittal referral can be worse than no referral at all, so don’t take it personally if she refuses. But hopefully you’ve carefully considered your relationship with this person so that the answer is a confident “Yes!”

【R5】________

Even if your contact agrees to put you in touch with the hiring manager, offer to take her to lunch so you can provide her with the information she needs to deliver a strong referral. Describe your major professional accomplishments, and relate them to why you think you would be an ideal candidate for the listed position. By offering up the information she needs, you not only increase your chances of obtaining an interview, but you also make her look good to her coworkers by contributing an informed recommendation.

Before you even know if you’ve obtained the interview, send your referrer a thank-you note. You’ll let her know that regardless of the outcome, you appreciate her time and effort. And even if this position doesn’t pan out for you, your graciousness will keep you top-of-mind if similar positions arise in the future!