Wikipedia:Reference desk/Archives/Science/2016 July 6

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July 6

Robin mother won't feed chicks

We have a American robin nesting in a hanging plant on our patio. She laid 3 eggs and all three hatched. But she doesn't seem to be feeding them and they are all quite lethargic. It's been several days now. There is a male nearby, presumably the father, and I understand that the males are rather standoffish, as is this one. I am considering putting some bait worms and berries in the nest so hopefully the chicks will eat, regain their strength, and start chirping for more, triggering the mother robin's instinct to feed them. What do you think of this plan ? StuRat (talk) 00:27, 6 July 2016 (UTC)

I think nature is red in tooth and claw. This borders on medical advice ;) anything we advise here could go terribly wrong. There's a widely held belief that birds have keen smell and if you merely "touch" a nestling you are likely to get it rejected by the parents. I have read that this is "generally" untrue, but, I think you'll just need to proceed at your own caution. If it were me, I would leave nature to it self. Maybe there's something "wrong" with them and if they don't survive to adulthood, they wouldn't "make it in the wild" anyway? And you feeding them is just prolonging the suffering. Vespine (talk) 01:25, 6 July 2016 (UTC)

That is generally untrue; with a few exceptions, birds tend to have a poor sense of smell. However, they do tend to have excellent vision and, given the importance of the location, I doubt it will be possible for the OP to mess around with the nest without them being seen. The tampering may have already signaled to the parents that the nest should be abandoned as dangerous. FYI, robins are likely covered by the Migratory Bird Treaty Act of 1918. Matt Deres (talk) 02:36, 6 July 2016 (UTC)

Another exception possibly being homing pigeons using olfactory navigation. Vespine (talk) 04:16, 6 July 2016 (UTC)

Birds know when to hold 'em and when to fold 'em. Robins tend toward starving the weakest in tough times. Very few animals need reminders about needing food to live; even the bird-brained have been doing this longer than we have. A chicken of mine recently killed her own premature baby, an hour or so after I went "D'aww!" at its wobbling and started thinking of names. Life sucks sometimes.

Helping the less fortunate is generally the nice thing to do, but helping creates caring, and caring for someone you can't save is taxing while they're alive and painful when they die. On the bright side, robins usually won't starve all three. I'll wish the big one well. InedibleHulk (talk) 07:48, 6 July 2016 (UTC)

Robins are born altricial i.e. with no feathers, eyes closed, entirely dependent on parents for food and warmth. If an adult bird does not return after about three hours then rescue will be necessary. A small bird will die if it doesn't eat for 48 hours. All too often baby birds are "rescued" unnecessarily, see TO “RESCUE” OR NOT - BABY BIRDS. Birds in rehabilitation should not be reared on worms. AllBestFaith (talk) 09:27, 6 July 2016 (UTC)

UPDATE: We left berries out on the patio, and they disappeared. That doesn't necessarily mean the robins ate them, as we have other critters around, but the chicks are doing better now, and we see the chicks' beaks wide open and begging for food. StuRat (talk) 00:55, 8 July 2016 (UTC)

Does cannibalism cause insanity?

According to Kuru (disease), a prion found in humans could cause insanity. However, do all humans have this prion? If the brain is not eaten, or the meat is thoroughly cooked, would cannibalism be healthy?--Hofhof (talk) 13:45, 6 July 2016 (UTC)

Yes. But don't eat too many near relatives. YohanN7 (talk) 14:02, 6 July 2016 (UTC)

According to this source, prions can only be "deactivated" by incinerating at 900 degrees Fahrenheit (482 Celsius) for 4 hours, by which time, your brain recipe would be seriously overdone. I shan't be going to your house for dinner, thank you all the same. Alansplodge (talk) 17:10, 6 July 2016 (UTC)

Humans don't all have the prion. The natural incidence of Creutzfeld-Jacob disease is quite low, and I have read claims it is less transmissible by eating than vCJD or kuru. The existence of multiple types of misfolded PrP is truly one of the weirdest things in biology - it's almost like a genetic system coded in the misfolding of a protein, which is utterly mysterious. That said, the incidence of diagnosed CJD will inevitably be lower than the incidence of some prions loose in the brain of someone simply thought to be a little old and a little slow by the time of death. Even supposing there is some kind of collective social memory of these risks, I've never understood how great armies, in times when there has been little reluctance to commit atrocities or suffer casualties, would risk starvation or at least degradation of combat readiness while camped in the middle of so much freshly slaughtered meat. Wnt (talk) 17:37, 6 July 2016 (UTC)

Japanese war crimes#Cannibalism:

"Perhaps the most senior officer convicted of cannibalism was Lt Gen. Yoshio Tachibana (立花芳夫,Tachibana Yoshio)"

"The airmen were beheaded on Tachibana's orders. Because military and international law did not specifically deal with cannibalism, they were tried for murder and "prevention of honorable burial"." Sagittarian Milky Way (talk) 10:06, 8 July 2016 (UTC)

"It's simply not done" applies to a multitude of activities. -- Jack of Oz ^{[pleasantries]} 22:45, 7 July 2016 (UTC)

Point at which pressure converts solid into liquid

Is there a term for the collection of points at which pressure causes a solid to become a liquid? For example, "At -17°, ice becomes water at [pressure 1], as it does at -5° at a pressure of [pressure 2]. These points, together with other points manifesting the same phenomena, are known as the [term that I'm looking for]". Nyttend (talk) 16:28, 6 July 2016 (UTC)

Pressure melting point? I don't think there's a more specific term, it is simply the melting point defined at a given pressure. —Akrabbim^talk 17:06, 6 July 2016 (UTC)

Thanks; all I could think of was "triple point", and I knew it was wrong. Lake Vostok now improved with a link to pressure melting point. Nyttend (talk) 17:09, 6 July 2016 (UTC)

Phase diagram Wnt (talk) 17:30, 6 July 2016 (UTC)

It could be termed a phase boundary, but this is more likely the term for the physical surface of the ice water interface. Phase diagram boundary is a bit more descriptive. Diagrams can be multidimensional if you add some other aspect, such as a range of compositions, eg salinity, isotope composition, size of container, that can vary the melting point. Graeme Bartlett (talk) 23:28, 6 July 2016 (UTC)

Solidus - defines a line in pressure temperature space - see also liquidus (not just varying with temperature as that article says, but other variables including pressure, as Graeme mentions above) where you get 100% liquid. Mikenorton (talk) 09:18, 8 July 2016 (UTC)

Although that's only for a two or more component system, which is what I think of when hear the term phase diagram, so that wouldn't be appropriate for water. For a single component they're called "phase lines" as in the "solid/liquid phase line" here. Mikenorton (talk)

Heavy duty breakers

I often see heavy duty breakers being used for road works to dig up the road. They are very loud and I'm assuming cause a lot of vibrations. Can they not damage or causes cracks in nearby houses and other structures especially if they're old and weak for example old brick and timber houses? Clover345 (talk) 16:41, 6 July 2016 (UTC)

Yes. It's uncommon but not unheard of for restrictions to be placed on the use of such machinery when work is undertaken within the vicinity of buildings which might be affected by undue vibration - example in this Daily Hate story about Robbie Williams. I'm sure there's literature on the transmission of vibration through local terrain, and its effects on structures, but I can't point to any right now. --Tagishsimon (talk) 16:50, 6 July 2016 (UTC)

The article about jackhammers (pneumatic drills or demolition hammers in British English) used to break roadways mentions their bad health effects and here and here are safety warnings. This analysis includes in Table U-2 a summary of construction equipment vibration levels and effects on humans and buildings. AllBestFaith (talk) 18:11, 6 July 2016 (UTC)

And that's not mentioning the effects on pregnant women. --71.110.8.102 (talk) 21:58, 6 July 2016 (UTC)

In addition when they're breaking concrete so close to old houses, can it not cause the house to move as well from the ground being undermined? 2A02:C7D:B99D:100:5C90:4762:309B:3DFE (talk) 12:05, 9 July 2016 (UTC)