First-half results from specialist electronics component maker Laird were slightly ahead of market expectations, pushing the stock into the top spot on Thursday afternoon. The group posted organic year-on-year revenue growth of 10% and improved operating margins. Although revenue from its largest customer, Apple, was flat the company grew the top line 4% year-on-year, after an 8% currency headwind, thanks to improving cross-selling, diversifying its customer base and investment in innovation.Civil engineering consultancy WS Atkins was higher as shares recovered from Wednesday's falls, which came after the group revealed it was facing currency headwinds and challenges in its UK rail and aerospace businesses, but said it was still on track to hit full-year targets. Atkins, which has businesses in North America, the Middle East and Asia as well as in Europe, said it expected to be hit by an adverse currency impact of about £3m in the first half.Meanwhile, the share price of oil explorer Afren plummeted after the company said that it was temporarily suspending its chief executive officer Osman Shahenshah and chief operating officer Shahid Ullah pending the result of an investigation related to "unauthorised payments".Oriel and Canaccord Genuity both placed their target price and recommendation under review, while Investec put its target price under review and downgraded the stock from 'buy' to 'hold'.Construction group Balfour Beatty fell after it called off its planned merger with rival Carillion, which also dropped into the red, after the latter said it would only press ahead with the deal if Balfour ditched plans to sell its Parsons Brinckerhoff US engineering division. Balfour, which has faced challenges in the last few months resulting in the departure of chief executive Andrew McNaughton, said the decision by Carillion was "wholly unexpected" and was contrary to the terms on which Balfour agreed to start the merger talks.FTSE 250 - RisersLaird (LRD) 286.20p +6.91%Workspace Group (WKP) 611.50p +2.26%Wetherspoon (J.D.) (JDW) 745.00p +2.19%Barr (A.G.) (BAG) 663.50p +2.08%Carphone Warehouse Group (CPW) 334.00p +1.46%Hochschild Mining (HOC) 161.10p +1.45%Dignity (DTY) 1,352.00p +1.43%Daejan Holdings (DJAN) 4,750.00p +1.34%Atkins (WS) (ATK) 1,324.00p +1.30%Rightmove (RMV) 2,262.00p +1.25%FTSE 250 - FallersAfren (AFR) 108.80p -26.88%Pace (PIC) 307.60p -8.83%Man Group (EMG) 119.20p -5.47%Supergroup (SGP) 1,009.00p -5.17%Balfour Beatty (BBY) 240.00p -5.03%IP Group (IPO) 181.20p -4.63%Carillion (CLLN) 338.00p -4.30%ICAP (IAP) 346.20p -4.07%Jupiter Fund Management (JUP) 378.40p -3.96%Kazakhmys (KAZ) 327.90p -3.67%NR