Kazakhmys was in the bottom spot on the second tier after a week of unimpressive broker comments. On Tuesday Deutsche Bank reiterated its 'sell' rating, while Investec reduced its price target from 294p to 280p. The group has recently unveiled plans for a restructuring, which will see it split into separate public and private entities. Oxford Instruments was also in the red after Investec said that in the 2014/15 financial year, the benefits of a pick-up in trading in its fourth quarter will be offset by the impact of non-repeating projects, operational problems at Omicron, a rising tax rate and currency headwinds. While the company is said to have "the potential for significant growth", the broker has kept a 'hold' rating, "pending clearer evidence of a sustained recovery in Oxford Instruments' markets". It did, however, raise its target price from 1,400p to 1,500p.WH Smith was lower after reporting that half-year High Street sales declined 7% year-on-year and dropped 6% on a like-for-like (LFL) basis. Total group sales fell to £613m from £638m previously, while LFL fell 4%. Despite this, the group did lift its dividend payment by 15%. Meanwhile, recruitment firm Hays was up after it reported a solid increase in quarterly net fee growth, helped by improved conditions across many of its key markets, leading to increased expectations for full-year profits.The group expects full-year operating profit to be towards the top of the current range of market estimates of around £141m, based on a good start to the second half overall and strong performances in key markets such as the UK and Germany.Natural resources, land and property consultancy RPS Group rose on the news it has acquired Clear Environment Consultants as part of the expansion of its European business. Clear, which provides services primarily to the water industry, has been bought for a maximum consideration of £8.34m.FTSE 250 - RisersPerform Group (PER) 263.00p +5.41%Hays (HAS) 152.50p +5.39%Elementis (ELM) 291.60p +4.89%Workspace Group (WKP) 613.00p +3.81%Worldwide Healthcare Trust (WWH) 1,278.00p +3.48%Imagination Technologies Group (IMG) 214.10p +2.93%Renishaw (RSW) 1,960.00p +2.78%Evraz (EVR) 84.10p +2.62%RPS Group (RPS) 320.50p +2.49%Smith (DS) (SMDS) 314.60p +2.24%FTSE 250 - FallersKazakhmys (KAZ) 246.20p -3.68%Moneysupermarket.com Group (MONY) 170.20p -3.13%Booker Group (BOK) 151.70p -2.69%Entertainment One Limited (ETO) 314.60p -2.60%Oxford Instruments (OXIG) 1,395.00p -2.52%Ocado Group (OCDO) 394.70p -2.37%Debenhams (DEB) 77.85p -2.08%WH Smith (SMWH) 1,146.00p -2.05%Carphone Warehouse Group (CPW) 322.70p -1.86%Restaurant Group (RTN) 662.00p -1.85%NR