Wikipedia:Reference desk/Archives/Science/2017 November 27

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November 27

why are winters along the Atlantic northeast colder?

Why are winters along the Atlantic Northeast coast colder than winters along the Pacific Northwest coast? — Preceding unsigned comment added by 73.133.84.160 (talk) 02:31, 27 November 2017 (UTC)

Because the global wind streams mostly blow from the west, in an eastward direction. That way over the Pacific coast (you refer to usa/canada i assume) the air comes from the see and at the atlantic coast it comes from land. Because a (fluid) body of water is a much better thermal heat storage than a land mass, the air above see or Oceanic climate is always a bit colder in the summer and a bit milder in the winter. Continental climate is the other way around, hotter in the summer and colder in the winter in comparison. So in winter time the pacific northwest coast benefits from the oceanic climate because of the general wind stream and the atlantic northeast coast has a colder continental climate, no matter its close to the sea. --Kharon (talk) 03:14, 27 November 2017 (UTC)

And to get to the Atlantic the air has to go over the Coast Ranges, Cascades, Rockies, over a thousand miles of plains, multiple rows of Appalachians and more land. Each time it gets lifted Pacific humidity gets rained or snowed out of it, the latent heat of condensation is released I believe and it gets cooled by contact with high altitude air (the expansion part of the cooling gets reversed with compressive heating on the way down) and by Interstate 25 the air has lost all it's oceanic characteristics, become very continental and the climate's only wet enough to support short grass. The main reason it gets wetter going east is humidity from the Gulf and Great Lakes. In Europe, continentalizing the air takes much more miles as Europe's north to south mountain ranges in the mid-latitudes aren't comparable. In addition, the Pacific Northwest is slightly more closer to the pole though the latitudes overlap. Sagittarian Milky Way (talk) 04:06, 27 November 2017 (UTC)

See also Ocean current. In the North Atlantic, the currents are going roughly anticlockwise, which means on the US side, they are bringing cold water down from the Arctic (while on the European side, they are bringing warm water up from the south). The same is happening in the Pacific, but here it is the US that get the warm water and Russia and Northern Japan that gets the cold. Iapetus (talk) 16:25, 27 November 2017 (UTC)

Are you sure you didn't get that backward? -- ToE 17:22, 27 November 2017 (UTC)

That is exactly backwards. In the northern hemisphere, the currents circulate in a roughly clockwise direction. See the map below. --Jayron32 17:35, 27 November 2017 (UTC)

Currents circulate clockwise in the north and anticlockwise in the south.

It goes clockwise at mid latitudes. I was referring to the far north, which from that map appears to go in the opposite direction.Iapetus (talk) 09:12, 28 November 2017 (UTC)

(edit conflict) The Humboldt Current runs north. The Gulf Stream runs north east and is prolonged in the North Atlantic Drift. See Physical oceanography. 92.27.49.50 (talk) 17:37, 27 November 2017 (UTC)

(edit conflict) Not quite that simple. In the northern North Atlantic the Labrador Current pulls cold water down towards the eastern seaboard of Canada and New England while the North Atlantic Drift splits off from the Gulf Stream to bring relatively warm water up past the British Isles and Norway. Further south, however, the circulation is more clockwise forming the North Atlantic Gyre. Mikenorton (talk) 17:38, 27 November 2017 (UTC)

The Gulf Stream keeps Svalbard quite warm for its latitude, but not Franz Josef Land which is quite close to Svalbard. The Gulf Stream doesn't reach it and winds are from the East there. Count Iblis (talk) 18:57, 27 November 2017 (UTC)

How much does it cost to run an air conditioner like this?

I have 12 computers upstairs - 11 SFFs consuming about 100 watts and one minitower consuming 140 watts or so. I can figure up how much electricity it takes to run these, but how approximately much electricity for air conditioning does it take to remove this much heat? Bubba73 ^{You talkin' to me?} 04:10, 27 November 2017 (UTC)

One rule of thumb is the same amount again - 1240 watts. However cooling heat pumps can have about 3:1 efficiency ratio, and you may be able to use natural cooling for some parts of the year, even though they maybe in the Southern United States. So the figure may be less. Graeme Bartlett (talk) 06:54, 27 November 2017 (UTC)

That could be quite expensive to cool. It would be so much better if architects put some effort into things like wind towers instead of always battling with heat technologically when installing HVAC. Dmcq (talk) 15:08, 27 November 2017 (UTC)

I have a heat pump. That 3:1 ratio means that it takes 3 times as much electricity? (Right now i have the window open up there to let heat out. It was 86F - now it is down to 83F.) Bubba73 ^{You talkin' to me?} 15:49, 27 November 2017 (UTC)

No, one third a much. See Coefficient of performance and Air conditioning#Seasonal energy efficiency ratio. The mandated minimum SEER rating of 13 translates to a COP of 3.43, which means that a minimally compliant AC would consume 1240 W / 3.43 = 362 W to dissipate that 1240 W of extra heat. -- ToE 16:21, 27 November 2017 (UTC)

OK, then the A/C doesn't add too much to the cost of running the computers, and I don't need it all of the time. Bubba73 ^{You talkin' to me?} 16:28, 27 November 2017 (UTC)

So the OP's hardware is generating just over a kilowatt of heat. Lets brake this down into practicalities. The CPU's will shut down if it they get too hot. High volume forced air ventilation may be all that is needed to prevent this and is much cheaper to run. However, if Bubba73 lives in a climatic zone where ambient temperatures make even this solution effective on it own, he might try adding a mist system. With the latter, one has to consider the water quality, as one doesn’t what salt deposits accumulating on the mother boards. Or he may live in an area where the relative humidity is so high that misting will be ineffective. In which case an A/C adjusted so that its evaporating coils runs just above the dew point temperature, allowing cooler (yet damp air). (which soaks up more heat) to flow through. In other words -run the A/C at a higher temperature than seems at first logical. Then divide the problem by half's. If at n degs it work OK, increase the temperature further. If that works, increase it again. If problems occur, reduce the temperature by half etc. Explore the simplest solutions first. Aspro (talk) 16:59, 27 November 2017 (UTC)

the humidity is high here. Things like Speccy show that the CPUs are not getting too hot. Bubba73 ^{You talkin' to me?} 17:33, 27 November 2017 (UTC)

Then why do you wish to cool things down ! ! ?Aspro (talk) 18:35, 27 November 2017 (UTC)

High humidity makes it seem hotter. But with these 12 computers running upstairs, and the A/C off, it is reaching 86-87F up there. I have the windows open now and it has cooled down to 81F. But for about 2 days I had the heat running downstairs and the A/C upstairs! Bubba73 ^{You talkin' to me?} 19:46, 27 November 2017 (UTC)

If you make the watts per square foot of house as equal as possible with a moderate bias to lower maybe you could even that out and use nothing? And program them to use the percent of CPU power that minimizes heating and cooling? Sagittarian Milky Way (talk) 20:33, 27 November 2017 (UTC)

It is actually possible to water cool a computer. [1] Given the expense of all this cooling, it might be worth the trouble. I bet a sufficiently elaborate liquid cooling system could take the fluid entirely outside of the house to cool, or perhaps better, cool it in an outbound existing ventilation duct to ensure it gets a constant amount of cooling assuming a relatively climate controlled house indoors to avoid freezing or too much heat outside. I wonder if this has something to do with those absurd Bitcoin prices -- you would be amazed what price I didn't buy those things at because I was sure (as I continue to be) that the scheme will collapse any day now. Wnt (talk) 23:44, 27 November 2017 (UTC)

Fascinating stuff. Back to the future! Old IBM systems such as the IBM System/390 ES/9000 Enterprise Systems Architecture ESA family sometimes had built-in water-cooled systems. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:00, 28 November 2017 (UTC)

12 computers each 100-140 W? That's a rather weird usage profile. Mining bitcoin? Obviously, if that is what you have, then that is what you have. However, I'd probably think about whether there are tasks that can be consolidated to reduce the number of machines that need to be on. Alternatively, some of the newer SFF computers aim for significantly lower power usage under load. Dragons flight (talk) 17:22, 28 November 2017 (UTC)

It seems more practical to just run the A/C, which is what I'm doing. I was estimating the usage before. Checking the UPS software, they are using just under 1500 watts. They are all working - it wouldn't make sense to have that many computers idling. These are older computers, all i7s - mostly Sandy Bridge and one Ivy Bridge. But I was able to get them refurbished at a good price. (I couldn't afford that many new computers.) Bubba73 ^{You talkin' to me?} 01:41, 30 November 2017 (UTC)

What biological protection do trees have against lightening?

Trees get hit by lightning all the time. Haven't the tall ones, like coconut, developed some sort of protection against lightning? Or is it too unlikely to warrant an evolutionary response? Bobatnet (talk) 04:57, 27 November 2017 (UTC)

That seems like a lot of energy to handle, and a rare occurance. I don't have an answer to this question, but the opposite case—evolving to take advantage of and even require perhaps-rare severe stresses even to the extent of forest fires—is well known. See serotiny. DMacks (talk) 05:06, 27 November 2017 (UTC)

In my unscientific observations, most trees die after being struck by lightning, but some survive. Bubba73 ^{You talkin' to me?} 05:12, 27 November 2017 (UTC)

Lightening is essential for trees; lightning not so much. AndrewWTaylor (talk) 11:29, 27 November 2017 (UTC)

I suspect that your observations may be biased—unless you're carefully watching for strikes during a storm and verifying the condition of the trees afterward, then your sample is going to be based on trees that were conspicuously damaged by strikes. (If a tree were struck by lightning but not seriously damaged, would you know a lightning strike occurred?) Bear in mind that between 70% and 90% of soft, squishy people survive being struck by lightning; trees tend to be a lot more tolerant of most sorts of abuse. TenOfAllTrades(talk) 21:01, 27 November 2017 (UTC)

I said that it was unscientific, but you can tell when a tree has been hit by lightning - the bark splits along the length of the tree. We had several trees hit by lightning where I grew up - you would hear the crack and then later you could tell which one was hit. Only one or two survived. Bubba73 ^{You talkin' to me?} 21:20, 27 November 2017 (UTC)

Lightning strike says that 9-10% of people hit by lightening die. It also says "These statistics do not reflect the difference between direct strikes, where the victim was part of the lightning pathway; indirect effects of being close to the termination point, like ground currents; ..." The trees were struck directly. Bubba73 ^{You talkin' to me?} 21:25, 27 November 2017 (UTC)

Might be worth pointing out here that lightening is actually a real word, which is probably why it isn't triggering people's spell-checkers. But it doesn't mean "electrical discharge". It means "making lighter", as in lightening the load. --Trovatore (talk) 20:42, 28 November 2017 (UTC)

Its purpose is likely dominated by providing photosynthesis opportunities, but the creation of a forest canopy, where the crowns of the trees form a more-or-less even layer would minimize the chance of an individual tree being struck. I don't know how much of a piece lightning would play in that, but my guess is that it's not zero. Matt Deres (talk) 15:32, 27 November 2017 (UTC)

Here's a recent paper that tries to model electrical conduction of lightning to ground in trees. It notes variations in electrical conductivity as a function of tree size and species, and also offers some interesting suggestions about how lianas (semi-parasitic woody vines) may act as natural lightning rods to divert a strike away from the tree. It's certainly possible that vulnerability to lightning could act as a selective pressure to encourage changes in tree shape and moisture content, as well as alter the relationship between trees and their neighbors and parasites. TenOfAllTrades(talk) 21:01, 27 November 2017 (UTC)

Lightning is less hazardous directly than any fire and conflagration that may follow. Many a tree lives fine after a lightning strike -- ought to be able to find photo examples. GeeBee60 (talk) 18:36, 1 December 2017 (UTC)

Surgery leaves woman ‘drowning in her own poo’

See here. After reading this article I'm left wondering why she isn't given total bowel rest by putting her on total parenteral nutrition. Count Iblis (talk) 10:26, 27 November 2017 (UTC)

No one here is her physician, so no one here can tell you why they did or did not give her any particular procedure. --Jayron32 12:11, 27 November 2017 (UTC)

• The original story is here: http://www.bristolpost.co.uk/news/bristol-news/horrifying-x-ray-woman-drowning-830976 (it's local to me). Even by the spiralling standards of web journalism and the local paper being barely adequate for wrapping chips at its best, this is a particularly badly written and unclear story. Andy Dingley (talk) 12:47, 27 November 2017 (UTC)

Even in the case of nil per os, some feces are generated from shedding of the intestinal lining, secreted bile, and gut flora. Obviously, also, any feces already in the intestines will be unable to exit in the event of bowel obstruction. --47.157.122.192 (talk) 22:20, 27 November 2017 (UTC)

The more original story is at the Mirror. I smell a political angle on how this story is being told, but in general megacolon can have various causes that can be addressed in various ways. Bowel perforation can happen, but at the same time, depending on the degree of a nerve injury, regeneration can occur after varying periods of time [2]. (I should do better than this answer, but this is the direction I'm thinking...) Wnt (talk) 23:54, 27 November 2017 (UTC)

• There is no way feces can get into the abdominal cavity without a rupture in the digestive tract. This happened to me when I had diverticulitis which eventually caused a bowel rupture. The abdomen is essentially an empty fluid-filled cavity through which the digestive tract runs like a hose through a room, with most of the abdominal organs attached, except the kidney and reproductive organs, which have their own exits to the outside. The only natural openings of the digestive tract are the mouth and anus.

In my case, I was put on an NPO diet (see link above) and powerful intravenous antibiotics, then operated on to remove the lower 2/3rds of the colon. (This condition is common in my Father's family.) The fecal matter was removed by aspiration, both before and after the surgery when the anastomosis failed, again leaking feces into my coelum.

This treatment ran into the hundreds of thousands of dollars, of which I had to pay only a $500 deductible. One can read that hospitals that provide treatment only when pre-approved for payment might balk at such an expense. μηδείς (talk) 21:38, 28 November 2017 (UTC)

And now you're confusing surgery costs with pharmacy, and NICE. Andy Dingley (talk) 23:24, 28 November 2017 (UTC)

Is the pathophysiology of Parkinson's disease is lessions in corpus striatum?

I've found an Ukrainian book on Google which states: "The main disorders in CNS are lesions in striatum resulting in the diminished amount of dopaminergic neurons in the substantia nigra." Well, while I well read that the pathophysiology of Parkinson's disease is diminished amount of dopamine, I didn't see that it is a result of lesions in the corpus stratum. Is the Ukrainian book correct? 185.191.178.183 (talk) 23:31, 27 November 2017 (UTC)

Parkinson's disease is caused by the death of dopamine-producing neurons in the substantia nigra, which then leads to a lack of inhibitory input to the striatum, causing the symptoms of the disease. It does look like the lesions themselves are not in the striatum. Is the book in English? If so, was it translated into English? Can you link it? There could be translation issues here. --47.157.122.192 (talk) 23:47, 27 November 2017 (UTC)

It's an error, but an understandable one. PD is caused by loss of dopaminergic neurons in the basal ganglia. The striatum is the largest component of the basal ganglia, but it is not the place were the dopamine cells reside. Looie496 (talk) 23:46, 29 November 2017 (UTC)

Is it possible to invent car engine lubricant that's mostly graphite?

Or dust of a low melting point metal or metal alloy? If yes why isn't it done (lasts few miles? cost? R&D cost to benefit potential? oil change difficulty?..) Sagittarian Milky Way (talk) 23:40, 27 November 2017 (UTC)

Powdered graphite is well-known as a low-friction lubricant. However is has nothing like the load capacity of a hydrodynamic or hydrostatic bearing (oil wedge or pressurised oil film). Also the engine oil has an important function for cooling, particularly the heated area around the underside of the piston.

In the 1980s, some work did begin on engines with internal ceramic coatings for cylinder liners that would reduce heat transfer, and would also require less lubrication oil volume, so reducing windage losses and the need for pumping power. Andy Dingley (talk) 01:11, 28 November 2017 (UTC)

Babbitt (alloy) (low melting point) was once used for big-end bearings but no more (think they needed replacing every 500 miles). Graphite is great for low load applications like door locks. Not being oily they don't attract fluff and grit which in turn jam the lock's tumblers. The modern graphine sheet doesn't appear to hold much hope either, as it is not self repairing like an oil film. To be Tribology correct – the oil forms a metal/oil emulsion just microns thick rather that the oil keeping the two surfaces compleaty seperate as in a say a fluid bearing. Ceramic coatings for cylinder liners appeared to be very promising as they significant increased engine efficiency – due to not so much heat being wasted. Unfortunately the thermal effects of expansion and contraction during running time and when the engine was off and cooled down, caused the ceramic linings to crack and break up. Modern synthetic lubricants based on silicon can mitigate much of the temperature problems associated with petroleum based lubricants but that leads us back to current technology being the best cost effective solutions. Maybe in the future, amorphous diamond (by Chemical vapor deposition ) could coat bearing surfaces but practical applications are still a long way off in the future. Aspro (talk) 16:38, 28 November 2017 (UTC)

Babbitt, in a car engine with 1950s era lubrication (i.e. decent filtration, flow rates and oil chemistry), should be good for about 25,000 miles. Andy Dingley (talk) 16:46, 28 November 2017 (UTC)