Ground engineering specialist Keller was lower on Monday, providing a drag on the construction and materials sector.The group's shares edged 0.13% lower to 449p after it revealed a massive 70% drop in half-year pre-tax profit following floods in Australia and geopolitical issues in the Middle East and North Africa. Sector peers Balfour Beatty, Norcros and Morgan Sindall were also in the red.GKN is making gains, driving the automobiles sector to the top of the pile.The global engineering giant - which is involved in the automotive, powder metallurgy, land systems and aerospace - rose 2.27% higher to 229.8p at 15:44, ahead of its interim results due on Wednesday.The firm announced on Thursday 28 July that it would acquire the all-wheel drive components businesses of German firm Getrag for £283m.BCTop performing sectors so far todayAutomobiles & Parts 5,379.89 +2.40%Banks 4,159.87 +0.65%Mining 25,017.43 +0.45%Oil Equipment, Services & Distribution 24,515.61 +0.44%Real Estate Investment & Services 1,657.06 +0.39%Bottom performing sectors so far todayIndustrial Transportation 2,499.44 -2.65%Industrial Metals & Mining 7,228.20 -2.45%Construction & Materials 3,682.99 -1.70%Forestry & Paper 6,349.72 -1.59%General Retailers 1,622.68 -1.45%