Charles Stanley has highlighted some short-term turbulence at BBA Aviation following the recent share price decline, but has kept its buy rating on the aviation support and aftermarkets services provider expecting long-term structural growth."Given the downgrade to US [gross domestic product] growth forecasts, there may be some short term volatility in US business jet usage. However the price has fallen by c. 23% since the beginning of July which we believe encompasses any potential short term weakness in demand," said analyst Peter Ashworth and Siral Shah. The target price is cut from 250p to 230p due to the uncertainty in the US economy.UBS has upgraded FTSE 250 recruitment firm Hays from neutral to buy, saying that while short- and medium-term macro concerns are rising, the group still has good growth prospects in the long-term."We continue to believe that Hays is a good business with well-established and strong franchises in professional staffing, and a meaningful and fast-growing international presence (62% of net fees in 1H11 came from outside the UK)," the Swiss broker said.The target price is left at 105p.Peel Hunt has reiterated its buy rating on Grainger, the FTSE 250 residential landlord, saying that the group's interim management statement released on Thursday showed "further resilient data"."Led by a management team which is delivering visible corporate deals to maximise value in a stagnant housing we continue to see clear potential in Grainger's shares - trading at little over half estimated break-up," the broker said.A target price of 140p is kept.BC