Recently biologists have been interested in a tide-associated periodic behavior displayed by the diatom Hantzschia virgata, a microscopic golden-brown alga that inhabits that portion of a shoreline washed by tides (the intertidal zone).Diatoms of this species, sometimes called "commuter" diatoms, remain burrowed in the sand during high tide, and emerge on the sand surface during the daytime low tide. Just before the sand is inundated by the rising tide, the diatoms burrow again. Some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change in pressure caused by tidal movement. However, when diatoms are observed under constant conditions in a laboratory, they still display periodic behavior, continuing to burrow on schedule for several weeks This indicates that commuter diatoms, rather than relying on environmental cues to keep time, possess an internal pacemaker or biological clock that enables them to anticipate periodic changes in the environment. A commuter diatom has an unusually accurate biological clock, a consequence of the unrelenting environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.

    This is not to suggest that the period of this biological clock is immutably fixed. Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors-including changes in the tide's hydrostatic pressure, salinity, mechanical agitation, and temperature-can alter the period of its biological clock according to changes in the tidal cycle. In short, the relation between an organism's biological clock and its environment is similar to that between a wristwatch and its owner: the owner cannot make the watch run faster or slower, but can reset the hands. However, this relation is complicated in intertidaldwellers such as commuter diatoms by the fact that these organisms are exposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.

    The sloth bear, an insect-eating animal native to Nepal, exhibits only one behavior that is truly distinct from that of other bear species: the females carry their cubs (at least part-time) until the cubs are about nine months old, even though the cubs can walk on their own at six months. Cub-carrying also occurs among some other myrmecophagous (ant-eating) mammals; therefore, one explanation is that cub-carrying is necessitated by myrmecophagy, since myrmecophagy entails a low metabolic rate and high energy expenditure in walking between food patches. However, although polar bears' locomotion is similarly inefficient, polar bear cubs walk along with their mother. Furthermore, the daily movements of sloth bears and American black bears—which are similar in size to sloth bears and have similar-sized home ranges— reveal similar travel rates and distances, suggesting that if black bear cubs are able to keep up with their mother, so too should sloth bear cubs.

    An alternative explanation is defense from predation. Black bear cubs use trees for defense, whereas brown bears and polar bears, which regularly inhabit treeless environments, rely on aggression to protect their cubs. Like brown bears and polar bears (and unlike other myrmecophagous mammals, which are noted for their passivity), sloth bears are easily provoked to aggression. Sloth bears also have relatively large canine teeth, which appear to be more functional for fighting than for foraging. Like brown bears and polar bears, sloth bears may have evolved in an environment with few trees. They are especially attracted to food-rich grasslands; although few grasslands persist today on the Indian subcontinent, this type of habitat was once widespread there. Grasslands support high densities of tigers, which fight and sometimes kill sloth bears; sloth bears also coexist with and have been killed by tree-climbing leopards, and are often confronted and chased by rhinoceroses and elephants, which can topple trees. Collectively these factors probably selected against tree-climbing as a defensive strategy for sloth bear cubs. Because sloth bears are smaller than brown and polar bears and are under greater threat from dangerous animals, they may have adopted the extra precaution of carrying their cubs. Although cub-carrying may also be adoptive for myrmecophagous foraging, the behavior of sloth bear cubs, which climb on their mother's back at the first sign of danger, suggests that predation was a key stimulus.

    Extensive research has shown that the effects of short-term price promotions on sales are themselves short-term. Companies' hopes that promotions might have a positive aftereffect have not been borne out for reasons that researchers have been able to identify. A price promotion entices only a brand's long-term or "loyal" customers; people seldom buy an unfamiliar brand merely because the price is reduced. They simply avoid paying more than they have to when one of their customary brands is temporarily available at a reduced price. A price promotion does not increase the number of long-term customers of a brand, as it attracts virtually no new customers in the first place. Nor do price promotions have lingering aftereffects for a brand, even negative ones such as damage to a brand's reputation or erosion of customer loyalty, as is often feared.

    So why do companies spend so much on price promotions? Clearly price promotions are generally run at a loss, otherwise there would be more of them. And the bigger the increase in sales at promotion prices, the bigger the loss. While short-term price promotions can have legitimate uses, such as reducing excess inventory, it is the recognizable increase in sales that is their main attraction to management, which is therefore reluctant to abandon this strategy despite its effect on the bottom line.

    In American Genesis, which covers the century of technological innovation in the United States beginning in 1876,Thomas Hughes assigns special prominence to Thomas Edison as archetype of the independent nineteenth-century inventor. However, Hughes virtually ignores Edison's famous contemporary and notorious adversary in the field of electric light and power,George Westinghouse. This comparative neglect of Westinghouse is consistent with other recent historians' works, although it marks an intriguing departure from the prevailing view during the inventors' lifetimes (and for decades afterward) of Edison and Westinghouse as the two "pioneer innovators" of the electrical industry.

    My recent reevaluation of Westinghouse, facilitated by materials found in railroad archives, suggests that while Westinghouse and Edison shared important traits as inventors, they differed markedly in their approach to the business aspects of innovation. For Edison as an inventor, novelty was always paramount: the overriding goal of the business of innovation was simply to generate funding for new inventions. Edison therefore undertook just enough sales, product development, and manufacturing to accomplish this. Westinghouse, however, shared the attitudes of the railroads and other industries for whom he developed innovations: product development, standardization, system, and order were top priorities. Westinghouse thus better exemplifies the systematic approach to technological development that would become a hallmark of modern corporate research and development.

    Acting on the recommendation of a British government committee investigating the high incidence in white lead factories of illness amongemployees, most of whom were women, the Home Secretary proposed in 1895 that Parliament enact legislation that would prohibit women from holding most jobs in white lead factories. Although the Women's Industrial Defence Committee (WIDC), formed in 1892 in response to earlier legislative attempts to restrict women's labor, did not discount the white lead trade's potential health dangers, it opposed the proposal, viewing it as yet another instance of limiting women's work opportunities. Also opposing the proposal was the Society for Promoting the Employment of Women (SPEW), which attempted to challenge it by investigating the causes of illness in white lead factories. SPEW contended, and WIDC concurred, that controllable conditions in such factories were responsible for the development of lead poisoning.SPEW provided convincing evidence that lead poisoning could be avoided if workers were careful and clean and if already extant workplace safety regulations were stringently enforced. However, the Women's Trade Union League (WTUL), which had ceased in the late 1880's to oppose restrictions on women's labor, supported the eventually enacted proposal, in part because safety regulations were generally not being enforced in white lead factories, where there were no unions (and little prospect of any) to pressure employers to comply with safety regulations.