Shares in Aveva have continued their rise this week as City rumours about a potential US takeover have bubbled to the surface after almost a year lying dormant.The engineering software group last September issued a profit warning related to the plunging oil price that scared off many investors and the apparent interest of US engineering conglomerate Emerson.But the US company's chief executive David Farr has recently said he is looking to pursue sizeable deals in order to placate anxious investors.After spending time with the company recently, Credit Suisse confirmed Emerson was "actively" considering strategic options."With a diverse portfolio, under-levered balance sheet, and several strong global franchises, EMR is clearly well-placed to enact considerable strategic change. We think the CEO sees this, and is now willing to undertake several such steps, which should help reverse the stock's performance, and improve investor sentiment (which has become extremely negative)."Aveva has been coincidentally connected to Emerson last summer and the new whispers seem equally speculative, though some media reports have mentioned a possible private-equity cash offer in the region of £24 a share.