The findings suggested that the plants' NOx emissions could result in a 35% increase in the number of days when ozone levels exceeded the upper threshold set by the US Environment Protection Agency.

BBC: Invasive plant 'increases ozone pollution'

Vice-President Joe Biden and Mitch McConnell, the Senate Minority Leader, who led the final talks, agreed to set the crucial threshold for the new tax rate for upper-income individuals at four hundred thousand dollars (and four hundred and fifty thousand dollars for families).

NEWYORKER: The House of Pain

In addition to giving the legislature's upper house this direct role in treaty-making, the Framers enshrined in the Constitution a high threshold for such consent: Not just a simple majority but fully two-thirds of the Senate must give their approval for any treaty to be ratified.

CENTERFORSECURITYPOLICY: Quality control or rubber stamp?