Line	The argument for “monetizing”—or putting a
	monetary value on—ecosystem functions may be
	stated thus: Concern about the depletion of natural
	resources is widespread, but this concern, in the
(5)	absence of an economic argument for conservation,
	has not translated into significant conservational
	progress. Some critics blame this impasse on
	environmentalists, whom they believe fail to address
	the economic issues of environmental degradation.
(10)	Conservation can appear unprofitable when compared
	with the economic returns derived from converting
	natural assets (pristine coastlines, for example) into
	explicitly commercial ones (such as resort hotels).
	But according to David Pearce, that illusion stems
(15)	from the fact that “services” provided by ecological
	systems are not traded on the commodities market,
	and thus have no readily quantifiable value. To
	remedy this, says Pearce, one has to show that all
	ecosystems have economic value—indeed, that all
(20)	ecological services are economic services. Tourists
	visiting wildlife preserves, for example, create
	jobs and generate income for national economies;
	undisturbed forests and wetlands regulate water
	runoff and act as water-purifying systems, saving
(25)	millions of dollars worth of damage to property
	and to marine ecosystems. In Gretchen Daily’s
	view, monetization, while unpopular with many
	environmentalists, reflects the dominant role that
	economic considerations play in human behavior,
(30)	and the expression of economic value in a common
	currency helps inform environmental decision-making
	processes.

Line	When asteroids collide, some collisions cause
	an asteroid to spin faster; others slow it down. If
	asteroids are all monoliths—single rocks—undergoing
	random collisions, a graph of their rotation rates
(5)	should show a bell-shaped distribution with statistical
	“tails” of very fast and very slow rotators. If asteroids
	are rubble piles, however, the tail representing the
	very fast rotators would be missing, because any
	loose aggregate spinning faster than once every few
(10)	hours (depending on the asteroid’s bulk density)
	would fly apart. Researchers have discovered that
	all but five observed asteroids obey a strict limit on
	rate of rotation. The exceptions are all smaller than
	200 meters in diameter, with an abrupt cutoff for
(15)	asteroids larger than that.
	The evident conclusion—that asteroids larger than
	200 meters across are multicomponent structures or
	rubble piles—agrees with recent computer modeling
	of collisions, which also finds a transition at that
(20)	diameter. A collision can blast a large asteroid to bits,
	but after the collision those bits will usually move
	slower than their mutual escape velocity. Over several
	hours, gravity will reassemble all but the fastest
	pieces into a rubble pile. Because collisions among
(25)	asteroids are relatively frequent, most large bodies
	have already suffered this fate. Conversely, most
	small asteroids should be monolithic, because impact
	fragments easily escape their feeble gravity.

    Customer loyalty programs are attempts to bond customers to a company and its products and services by offering incentives—such as airline frequent flyer programs or special credit cards with valuable benefits—to loyal customers. In support of loyalty programs, companies often invoke the "80/20" principle, which states that about 80 percent of revenue typically comes from only about 20 percent of customers. However, this profitable 20 percent are not necessarily loyal buyers, especially in the sense of exclusive loyalty. Studies have demonstrated that only about 10 percent of buyers for many types of frequently purchased consumer goods are 100 percent loyal to a particular brand over a one-year period. Moreover, 100-percent-loyal buyers tend to be light buyers of the product or service. "Divided loyalty" better describes actual consumer behavior, since customers typically vary the brands they buy. The reasons for this behavior are fairly straightforward: people buy different brands for different occasions or for variety, or a brand may be the only one in stock or may offer better value because of a special deal. Most buyers who change brands are not lost forever; usually, they are heavy consumers who simply prefer to buy a number of brands. Such multibrand loyalty means that one company's most profitable customers will probably be its competitors' most profitable customers as well. Still, advocates of loyalty programs contend that such programs are beneficial because the costs of serving highly loyal customers are lower, and because such loyal customers are less price sensitive than other customers. It is true that when there are start-up costs, such as credit checks, involved in serving a new customer, the costs exceed those of serving a repeat customer. However, it is not at all clear why the costs of serving a highly loyal customer should in principle be differ ent from those of serving any other type of repeat customer. The key variables driving cost are size and type of order, special versus standard order, and so on, not high-loyalty versus divided-loyalty customers. As for price sensitivity, highly loyal customers may in fact come to expect a price discount as a reward for their loyalty.