Travel operator Thomas Cook was flying high on Monday after upbeat comments from a number of brokers following last week's well-received third-quarter results.Citigroup raised its rating for the stock today from 'neutral' to 'buy', saying that the delivery of cost savings should "drive material upgrades to earnings". Panmure Gordon kept its 'buy' rating, saying that the company could resume dividend payments in 2015 - the last payout was in respect of the first half ended March 2011.In contrast, Domino's Pizza was heading the other way after Canaccord Genuity maintained it 'sell' stance, saying that the shares are too expensive "for a business that is now delivering forecast and balance sheet downgrades".Alent, the industrial materials company that used to be part of Cookson before its demerger, was lower after saying net sales value in the first half was broadly flat as copper damascene volumes were impacted by destocking and increased competition.Hedge fund manager Man Group was heading higher after UBS, Morgan Stanley and Societe Generale all lifted their target prices for the stock.Meanwhile, precious metals company Polymetal was hit by a downgrade by UBS from 'buy' to 'neutral' following a strong re-rating over the last month.FTSE 250 - RisersThomas Cook Group (TCG) 170.10p +5.65%Taylor Wimpey (TW.) 115.20p +3.97%Sports Direct International (SPD) 681.50p +3.41%Bellway (BWY) 1,478.00p +3.21%Drax Group (DRX) 674.00p +3.14%Perform Group (PER) 515.50p +3.10%WH Smith (SMWH) 825.50p +3.06%Man Group (EMG) 94.25p +3.01%Supergroup (SGP) 1,097.00p +3.00%Fidessa Group (FDSA) 2,070.00p +2.99%FTSE 250 - FallersDomino's Pizza Group (DOM) 571.00p -3.22%Alent (ALNT) 366.20p -2.86%Ladbrokes (LAD) 208.70p -2.57%Daejan Holdings (DJAN) 4,000.00p -2.56%Centamin (DI) (CEY) 36.49p -2.51%Bwin.party Digital Entertainment (BPTY) 138.00p -1.92%UBM (UBM) 727.00p -1.82%Polymetal International (POLY) 658.50p -1.79%Merchants Trust (MRCH) 494.00p -1.69%Investec (INVP) 435.60p -1.63%BC