A vital culture comes from competition and rivalry between institutions - state-funded arts councils and libraries, churches and campaigning groups as well as private and corporate sponsors.
The inevitable lack of enmity between sisters means their rivalry lacks the vital edge that made the eras of Martina Navratilova and Chris Evert and Steffi Graf and Monica Seles so compelling.
In Iraq, the Sunni tribes were vital to success; in Afghanistan, tribal rivalries may undo the best-laid plans.
But there are also networks and overlays of crime, corruption, political power plays, ethnic rivalries and local factions in competition for control over vital areas.
That campaign will not only borrow from an old yet vital N.L. fan base, but draw from old rivalries with cities such as Chicago and St . Louis those rivalries are alive and well, if the boos that greeted their names in a pre-game speech by the league's president, Leonard Coleman, were any indication.
But for others who like their sport to be vital and compelling, the argument is less credible: a rivalry that flows furiously in one direction erodes the senses; a rivalry which eddies to and fro elevates the soul.
Powell was given the childcare brief within a year of arriving in parliament and quickly made Labour competitive in a vital policy area that had been dominated by rivalry between Lib Dems and Tories.
On an increasingly complex battlefield shaped by long-simmering rivalries, the United States is now caught between two vital partners, the Kurds and its NATO ally Turkey.
Added Snyder, the "alliance is vital to lessen South Korea's vulnerability to North Korea and rising Asian rivalries". A related point was made by Van Jackson of the Center for a New American Century.
Such expertise is vital to any military or diplomatic ventures in the Middle East, where contradictory and crosscutting rivalries are endemic.
We demonstrate that estimation of farmers WTA is a potential tool to attach economic value to ecosystem services as public non-rivalry goods and services to influence adoption of PES conservation farm practices vital for restoration of degraded landscapes.
