In the first public polling we have seen since David Perdue's runoff win on Tuesday, Rasmussen Reports put out a robo-call survey today showing Perdue leading Democrat Michelle Nunn 46 percent to 40 percent.

Meanwhile, Landmark Communications showed Nunn leading 47 percent to Perdue's 43 percent.

Rasmussen, whose results tend to be Republican-leaning, reports their methodology like so:

The survey of 750 Likely Voters in Georgia was conducted on July 23-24, 2014 by Rasmussen Reports. The margin of sampling error is +/- 4 percentage points with a 95% level of confidence.

The Landmark poll info comes from this tweet by Channel 2 Action News' Lori Geary:

New numbers in from @LandmarkCommGA in #Senate race @MichelleNunnGA 47% @Perduesenate 43% out of 750 voters #wsbtv #gapol #gapop #gadems

If and when we get the crosstabs, we will share them. We suspect differing projections for the minority share of the electorate this fall.

UPDATE 6:55 p.m.: The Rasmussen poll has a sample that is only 25 percent black. The Landmark poll is 30.5 percent black.

Blacks made up about 28 percent of the electorate in 2010 and 30 percent in 2008 and 2012, with Barack Obama on the ballot. One of the Democrats' main hopes this year is to push black turnout to presidential-year levels.

Check back for a full analysis of the Senate race math Saturday on myajc.com and in Sunday's printed edition.