Resource group Talvivaara plunged after saying that it is unlikely to hit its nickel production targets this year as a result of flooding, scheduled maintenance and a fatality-related stoppage during its second quarter. Sector peer Avocet fell after Nomura slashed its target price on the stock by 45% following the recent production downgrade and news of a delayed project expansion. Oil explorer Salamander Energy fell after saying that test results at its dig in the Gulf of Thailand are "conclusive", with analysis showing that water is present in the tested section; in other words the Far East-1 well cannot be used for production.Software firm Anite rose after it reported strong results and boosted its dividend after a year that exceeded expectations. The company said its mobile phone testing division helped drive pre-tax profits up 75% to 28m. FTSE 250 - RisersOcado Group (OCDO) 79.50p +6.00%Centamin (DI) (CEY) 75.00p +5.93%Aquarius Platinum Ltd. (AQP) 50.25p +4.43%Bumi (BUMI) 322.90p +4.16%Wood Group (John) (WG.) 728.00p +3.78%Gem Diamonds Ltd. (DI) (GEMD) 206.40p +2.94%Brown (N.) Group (BWNG) 255.70p +2.90%Investec (INVP) 391.90p +2.86%EnQuest (ENQ) 113.20p +2.82%Hunting (HTG) 761.00p +2.77%FTSE 250 - FallersTalvivaara Mining Company (TALV) 146.30p -13.94%Avocet Mining (AVM) 70.25p -8.88%Man Group (EMG) 71.75p -3.63%FirstGroup (FGP) 225.20p -3.55%Britvic (BVIC) 324.40p -3.02%Yule Catto & Co (YULC) 139.50p -2.72%New World Resources A Shares (NWR) 325.50p -2.63%Salamander Energy (SMDR) 167.30p -2.51%Chemring Group (CHG) 268.40p -2.08%Barratt Developments (BDEV) 141.60p -2.07%NR