The research article is located here: <https://www.pnas.org/doi/full/10.1073/pnas.2101084119>; if you're interested in what "likely" means in this context, it may be beneficial to read through the article. My understanding is that the "likely" comes from it being an estimate using models, as the research article states.
> Substituting our empirically derived domestic emissions for those modeled in the RFS RIA would raise ethanol’s projected life cycle GHG emissions for 2022 to 115.7 g CO2e MJ−1—a value 24% above baseline gasoline (93.1 g CO2e MJ−1). The RIA estimate, however, includes improvements in feedstock and ethanol production efficiency that were projected to occur by 2022, such that the GHG intensity of ethanol produced at earlier time periods and over the life of the RFS to date is likely much higher [...].
My understanding is that they took the model used in the RFS RIA (when the RFS was first introduced), and plugged in what they've seen over the past few years to that model. Take that with what you will.
> And we're to assume that, without the production of fuel ethanol, the same land wouldn't be tilled and used for other crops?
With the increase in demand for corn for fuel usage, more fields are needed to plant the corn. Because the corn is for fuel, not food, food wouldn't have been planted in place of the corn had there not been fuel demand.
> We know that moving `Arc<Db>` will not change the location of the `Db` object, but there is no way to communicate this information to rustc.
There is! `std::pin`[0] does just this (and `Arc<T>` even implements `Unpin`, so the overall struct can be `Unpin` if everything else is `Unpin`). The page even includes a self-referential struct example, though it does use `unsafe`.
Are you sure this is the same code that triggers the vulnerability? Is the double `update` in the post itself unimportant (i.e., first updating with a 1-byte string, then the 4,294,967,295-byte string)? As I don't think this does that.
I don't think that's what they're claiming at all. I think what they're claiming is that it's far easier for individuals to be corrupt if their CEO is similarly corrupt, which is a completely different claim.
As far as I can tell, this can't actually work, because the return type of `fn next(&'a mut self)` should actually live for some lifetime `'b` that is shorter than `'a`, instead of at least as long as `'a`; mostly because `next` borrows `self` mutably.
> Substituting our empirically derived domestic emissions for those modeled in the RFS RIA would raise ethanol’s projected life cycle GHG emissions for 2022 to 115.7 g CO2e MJ−1—a value 24% above baseline gasoline (93.1 g CO2e MJ−1). The RIA estimate, however, includes improvements in feedstock and ethanol production efficiency that were projected to occur by 2022, such that the GHG intensity of ethanol produced at earlier time periods and over the life of the RFS to date is likely much higher [...].
My understanding is that they took the model used in the RFS RIA (when the RFS was first introduced), and plugged in what they've seen over the past few years to that model. Take that with what you will.
> And we're to assume that, without the production of fuel ethanol, the same land wouldn't be tilled and used for other crops?
With the increase in demand for corn for fuel usage, more fields are needed to plant the corn. Because the corn is for fuel, not food, food wouldn't have been planted in place of the corn had there not been fuel demand.