Post by Infinity Blade on Jan 3, 2020 0:10:06 GMT 5
A thread I posted on Carnivora. This is the Today ILearned thread, which I hope is self-explanatory.TIL (well over a year too late, in fact) that the Holocene has since been divided into its own three stages (Walker et al., 2018).
1.) The Greenlandian- 11,700 to 8,200 years ago. Began with the end of the Younger Dryas (something we'd already known kicked off the entire Holocene epoch). Named after the central Greenland ice sheet, where the North Greenland Ice Core project core project was drilled to bedrock in 2003.
2.) The Northgrippian- 8,200 to 4,200 years ago. Began with an abrupt cooling in global temperatures. This can be traced back to large amounts of freshwater from melting glaciers in Canada pouring into the North Atlantic, disrupting ocean currents. Named after the NGRIP1 ice core from central Greenland, the type section for the GSSP (Global Boundary Stratotype Sectoins and Points).
3.) The Meghalayan- 4,200 years ago to the present. Began with a drought that disrupted ancient civilizations in Greece, Egypt, Palestine, Syria, Mesopotamia, the Indus Valley, and the Yangtze River Valley. Named after the northeastern Indian state Meghalaya; this is where Mawmluh Cave, the stratotype locality, is located.
Post by Infinity Blade on Jan 7, 2020 8:47:44 GMT 5
TIL about this palm tree species->. This is Hyophorbe amaricaulis. The specimen pictured below is the last of its kind, being the only surviving specimen today. Also, Ginkgo biloba is the only extant species left in its whole division, Ginkgophyta. For anyone who may not be aware (as I was until just today), a division is the botanical and mycological equivalent of a phylum. It would be like if we humans were the only chordates left on the planet. Unfortunately, this species is also endangered.
Post by Ceratodromeus on Jan 20, 2020 6:37:53 GMT 5
Today i learned alligators eat Paddlefish
"It has been suggested that adult Paddlefish Polyodon spathula have no natural predators with the exception of humans and few heterospecific freshwater fishes which tend to target only early life stages (i.e., larvae, age-0 juveniles). However, we photographically documented another natural predator, the American alligator. The predation event took place in a small waterbody (0.8 ha) over a 45-minute period during which the alligator frequently transported the Paddlefish onto land, and retracted back into the water. This is the second event of its kind documented in this small river system. From a capture-recapture study, we have identified over 100 fish in the pool, 50 of which were surgically implanted with an acoustic transmitter for continuous monitoring of emigration. However, two have unexplainably disappeared, presumably from predation. Given the two known alligator mortality events, and two potential additional events suggested by transmitter disappearance, we presume adult Paddlefish predation may be more common than previously thought. Although adult Paddlefish were thought to have no natural predators, this newly documented predator-prey linkage provides support that alligator predation on Paddlefish may occur more frequently in southeastern waterbodies than previously believed, particularly when Paddlefish are in high abundance or in relatively small systems such as ours." www.sciencedirect.com/science/article/abs/pii/S2352249618300053
I was looking for any reliable figures for the head mass of a rhinoceros today (cuz...reasons). If you try looking it up via Google, you'll see figures of 800 to 1,000, even 2,000 pounds. So if by any chance any of you are nerdy enough to want to know how much a rhino's head weighs, now you'll know better (as if it weren't patently obvious that a rhino's head couldn't weigh 2,000 pounds).
Post by Infinity Blade on Jan 31, 2020 5:19:42 GMT 5
No it doesn't. Even if it had a 60 cm skull (which may be doubtful*), condylobasal length for adult hippo skulls is some 65 cm.
An ilium 37.5m long comes from Madsen (1976), it is not complete so it is an estimate but Hartman does seem to follow it as the pubis, ischium and skull bones also fit at that scale so, if the ilium needs to be reconstructed longer it wouldn't affect the rest of the skeleton and the skull would still come out at 47.5cm long.
I don't think it was that long however, I just checked the monograph of Eustreptospondylus and the overlapping parts are almost identical in size, which to me suggest its true length must have been about 36.5cm too. Perhaps Zanno et al. confused the preserved length with the estimated complete length?
Post by dinosauria101 on Jan 31, 2020 6:22:06 GMT 5
Oh, I was under the impression of 60 cm Marsho skull and 50 cm hippo skull when I posted that.
Deinonychus still has a pretty big head, as alluded to earlier by me in another thread. I did a little more digging into it, and if Deinonychus and Giganotosaurus were of equal mass, the former would have a head 128 percent to over 200 percent larger depending on the size estimate for the specimen in question. And this is that much bigger than the skull of Giganotosaurus, which is already very large.
As for why they didn't do it earlier, it looks like the only reason laboratories keep them around is so that they'll have genetic information on hand should the disease ever somehow reemerge. But in this instance, they compiled a digital record of rinderpest's entire genetic code, allowing them to destroy some of their samples.
Today I learned why we definitely need a speed limit of 30 kph within settlements, not 50 kph as is the norm. doi.org/10.1016/j.aap.2009.11.006 This is the result regarding pedestrian fatality risks in the case of collisions:
It wouldn’t be one of my posts if I didn’t have a regression equation to share, this is the dashed line, which is also the regression they cite in their conclusion: P=1/(1+exp(7.569-0.130v))
So in other words, getting hit by a car at 30 kph carries a 2.5% risk of death, getting hit at 50 kph carries a risk of 25.6%, i.e. ten times higher. This should come as no surprise, as a a 30 kph collision is equivalent of a 3.5 m fall (v=(2h*9.81)^0.5) while a 50 kph collision is the equivalent of a 10 m fall. And who would seriously think the latter isn’t way more dangerous than the former? In addition, of course going slower will also decrease braking distance and decrease the risk of a collision even happening to begin with. According to one study, introducing 20 mph-zones in London led to a decline in traffic casualties by over 40% (https://doi.org/10.1136/bmj.b4469) in those zones, most notably the number of fatal or serious injuries, especially in children
Interestingly, absolute fatality risks vary hugely depending on the analysis, but they all agree that going 50 kph carries several-fold higher risks of fatality for pedestrians than 30 kph: