Sixth-ranked Huskers Head to Las Vegas Invitational    With three dual victories under its belt, the No. 6 Nebraska wrestling team will travel to Las Vegas, Nev., this weekend to compete in the prestigious Cliff Keen Las Vegas Collegiate Invitational.    In its 19th year of existence, the tournament field consists of 53 teams.  It will feature team scoring, along with individual championships that will be awarded.     Competition opens on Friday morning and will continue through Saturday night.    Of the 53 teams that will be vying for the Las Vegas title, 11 are ranked by Amateur Wrestling News in its Top 20 tournament team poll.      Highlighting the field will be No. 5 Illinois, No. 6 Nebraska, No. 8 Lehigh, No. 9 Michigan and No. 10 Arizona State.  Other ranked schools participating will be No. 11 Boise State, No. 12 Edinboro, No. 16 Fresno State, No. 17 Pittsburgh, No. 19 Virginia Tech and No. 19 Ohio State.    Five of the nation's top-ranked wrestlers will also be competing this weekend.   Stephan Abas (125 pounds, Fresno State), Adam Tirapelle (149 pounds, Illinois), Otto Olson (174 pounds, Michigan), Brad Vering (197 pounds, Nebraska) and John Lockhart (Heavyweight, Illinois) will all take to the mats this weekend in Las Vegas.    The high level of competition excites head coach Mark Manning.       "This tournament has a lot of quality teams," Manning said.  "We are looking forward to facing off against the best."    Manning might get a boost this week with the return of NCAA qualifier Charles McTorry to the lineup.  McTorry has been sidelined with a nerve problem that causes numbness in his left arm since the end of last season.  Manning said on Monday that the chance of McTorry being ready to compete this weekend is 50/50.  If McTorry is unable to go at 184 pounds, his starting position will be filled again by natural 174-pounder Matt Fletcher.    NU's only other weight that is up for grabs is at 165 pounds where senior Ryan Schultz and junior Tony Denke will wrestle-off on Wednesday for the spot.    Conner nets highest career ranking in latest polls    After breezing through his first three matches of the season, senior Ati Conner has moved up the national 174-pound charts.    In the latest Amateur Wrestling News and InterMat individual rankings, Conner has achieved his highest individual ranking of his career. InterMat slates the Goleta, Calif., native in the No. 8 position, while AWN puts Conner in 10th.    Conner put together a 26-10 overall and 13-5 dual record during the 1999-2000 season, but faltered at the Big 12 Championships.  He narrowly missed out on an NCAA bid, dropping a 6-4 decision to Oklahoma State's Tony Gansen in the third-place match.    According to NU head coach Mark Manning, Conner's level of aggressiveness this season has been key to his success.    Conner will need to step it up another level this weekend, as the top three wrestlers in his weight class will be competing in Las Vegas.  Three Huskers take titles at Kaufman-Brand Open    Three redshirting Huskers took individual titles  at the Kaufman-Brand Open on Nov. 18  at the University of Nebraska-Omaha.    Sophomore Joey Malia, who competed on the varsity level for NU last season at 125 pounds, took the 133 pound title of the 20-and-under division. He used three pins on his way to the title, including a fall in the championship match over Roderick Ratcliff of UNO.    True freshman Travis Shufelt went 5-0, including a win over fellow Husker Travis Baker in the finals, to come away with the 149-pound title.    The nation's top prospect out of high school at 184 pounds last season, Travis Pascoe went 5-0 in his debut as a Husker winning his weight class.  Pascoe picked up two technical falls, a pin and a major decision in his five victories.    At 174 pounds, Matt Fletcher, who has filled in on NU's dual squad at 184 pounds in the absence of Charles McTorry, took second place in the 20-and-under division.  After winning his first four matches, Fletcher fell in the finals to Northern Iowa's Eric Hahn, 9-5.    Also at the weight, George Kirgan finished sixth, but not without paying a price.  Kirgan reinjured a knee that had nagged him throughout the summer.  The latest injury will require surgery and will likely hold him out of action until late February.