There are almost constant rule changes around the tackle laws, the breakdown and de-powering the scrum to reduce the amount of potential head trauma, but the professional era it's like an arms race. Even padding and head-gear, players seem to hit with even more force. And, like the article says, a lot of the concussions happen during the training sessions which is way more than the average amateur player would experience. It's still relatively soon to see the longer-term effects; the early batch of professionals from the mid/late 90s will soon be entering their 60s and I expect there will be more research papers..
I've not heard it before. I was an Application"s" DBA for several years, but this was specifically for Oracle's ERP suite of business applications. The role mixed straight DBA responsibilities with middleware and business administration.
It's the 4 engines which gives airlines A380/747 fuel cost problems. Both fulfil relatively niche markets and are gradually being displaced by the more-efficient and flexible twin-engine A350/787 types. We're just starting to see the secondary market for A380s now which is a good indicator for its long term commercial viability.
Twins are actually overpowered compared to comparably-sized quads due to engine-out climb requirements. In terms of raw seat-km-litre they are therefore slightly less efficient.
A good example is the old A340-300 quad, often maligned for being underpowered. Now that it is mostly retired data has emerged that it was more efficient than the rival 777-200 twin.
Where twins are cheaper is in terms of capital costs and consumables, though ETOPs requirements mean you need more technicians to service a twin ( separate teams for each engine ).
The US ExIm bank also provides billions in either direct loans or loan guarantees to foreign companies; this keeps the export market artificially high and effectively subsidises non-US operators and lessors too.
