Vesuvius, the de-merged Engineered Ceramics division of former FTSE 250 group Cookson, surged on Thursday, on day after its split from the chemicals division (now called Alent) became effective.In a research report yesterday, Investec gave the stock a 'hold' rating but expressed optimism regarding the company's long-term outlook."[The] de-merger of the former Cookson Group presents an opportunity to leave behind an unfortunate legacy. The group was a serial equity fund-raiser - to finance acquisitions or survival - and it had a record of value destruction. "In spite of the undoubted cyclicality of its markets, we believe that Vesuvius can break with the past and be managed prudently to generate robust cash flows, underpinning a good and progressive dividend." Insurance outfit Lancashire Holdings fell after estimating the impact Hurricane Sandy on the business will be in the region of $40-60m. Sector peer Amlin was flat after puttting its losses from the US superstorm at £145m, most of which comes from reinsurance claims.Construction firm Balfour Beatty gained after saying its half-owned Hong Kong builder, Gammon Construction, had won a contract worth £270m.Transport group Go-Ahead was lower after saying that it has compensated London Midland customers with £7m of benefits after they were disrupted by cancellations and delays last year.FTSE 250 - RisersVesuvius (VSVS) 350.90p +8.30%Talvivaara Mining Company (TALV) 107.40p +6.02%Perform Group (PER) 387.10p +4.62%Man Group (EMG) 86.65p +3.77%Ocado Group (OCDO) 82.60p +3.31%Centamin (DI) (CEY) 42.80p +3.23%Genus (GNS) 1,418.00p +2.83%Stobart Group Ltd. (STOB) 101.00p +2.54%Bumi (BUMI) 274.40p +2.16%Balfour Beatty (BBY) 273.80p +2.01%FTSE 250 - FallersFerrexpo (FXPO) 248.00p -3.84%Ruspetro (RPO) 76.55p -3.10%Computacenter (CCC) 409.60p -3.03%Chemring Group (CHG) 235.50p -2.69%Telecity Group (TCY) 780.50p -2.44%Workspace Group (WKP) 306.40p -2.36%Brown (N.) Group (BWNG) 370.80p -2.16%Victrex (VCT) 1,615.00p -2.06%NMC Health (NMC) 169.20p -1.86%Interserve (IRV) 380.40p -1.86%BC