(plural ring topologies) (computing) A network topology in which, in the physical case, every node of a network is connected to exactly two other nodes: one node designated as upstream and the other as downstream. A given node receives data from its upstream node and sends data to its downstream node.
Image copyright. The price of Brent crude oil has fallen below $50 a barrel for the first time since May 2009. It fell more than a dollar to $49.92 a barrel in early trading on Wednesday before edging back above the $50 mark. Slowing global growth and increased supply of oil and gas have pushed prices sharply lower in recent weeks.
The production cost of a barrel of shale oil ranges from as high as US$95 per barrel to as low US$25 per barrel, although there is no recent confirmation of the latter figure. The industry is proceeding cautiously, due to the losses incurred during the last major investment into oil shale in the early 1980s, when a subsequent collapse in the oil price left the projects uneconomical.