And through it all, Bernhardt has maintained a significant presence.
ABC's "Lost" (12.8 million) maintained a significant lead at 10 among adults 18 to 49 but matched its lowest ratings ever in that demographic.
Ever since the Persian Gulf war in 1991, the United States has maintained a significant military presence in the region, largely to keep President Saddam Hussein of Iraq in check.
But NBC has maintained a significant edge in profits over its network rivals in recent years largely on its ability to reach both young viewers and more affluent viewers.
NBC, Mr. Zucker said, has always maintained a significant edge among the most affluent and highly educated of the 18- to 49-year-old viewers, whom advertisers pay a premium to reach.
The body maintained a significant pace of activity through the 37th Congress, holding field hearings in several cities, receiving testimony from hundreds of witnesses and ultimately issuing over 3,000 pages of findings.
Obama maintained a significant lead over Romney in September in the national opinion polls, partly a result of a "convention bounce" and partly because of negative perceptions some held of his Republican challenger.
It pits the Islamic State (Isis), the Iraq and Syria-based group that has expanded deep into Africa since surging to international attention in 2014, against al-Qaida, the veteran extremist group, which has maintained a significant presence in much of the continent in recent years.
In comparison, the southeast has always maintained a significant population size relative to the northwest.
The last map, Fig. 6c, provides evidence about the geographic regions that maintained a significant positive spatial correlation ("High High" clusters) between 1991 SVI and 2011 SVI.
Expanded CD19.CAR-T cells maintained a significant fraction of CD45RA+CCR7+ T cells and demonstrated potent antitumor activity against CD19+ leukemic cells both in vitro and in vivo.
