Wikipedia:Reference desk/Archives/Science/2014 September 30

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September 30

Terminology Question

Does 'immunological response to X' mean something different than 'allergic reaction to X'?

Or are they two ways of labeling the same thing?

Thanks, CBHA (talk) 00:27, 30 September 2014 (UTC)

No, not the same. See: [1]. —71.20.250.51 (talk) 00:48, 30 September 2014 (UTC)

... which explains that the former is more general. An allergic reaction is one example of an immunological response. Dbfirs 07:14, 30 September 2014 (UTC)

Would it be correct to say that an allergic reaction is a "negative" event in that the person's immune system is overreacting to a perceived threat (allergen) which would not be a problem to the person if the immune system was able to ignore it? CBHA (talk) 13:48, 30 September 2014 (UTC)

That seems to be correct, given "Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment.", from allergy. SemanticMantis (talk) 15:46, 30 September 2014 (UTC)

Puppies and running water

Puppies are, in my experience, often scared of running water. Mum and I were talking about this the other day and mum suggested that perhaps there was something in the appearance of it that could trigger an instinct to avoid snakes - the wiggly, slithery motion of a small stream perhaps looking like a snake. Has there been any research into puppies' fear of running water, and into dogs' instinctive reactions to snakes? The dog we were reminiscing about later came to love water, insisting that we threw sticks for her to fetch into any body of water we came across on our walks. DuncanHill (talk) 02:24, 30 September 2014 (UTC)

The usual cursory means of finding research sources hasn't found anything specific to puppies and running water (quite a bit about dealing with dog's fear of water, etc.). While speculation should be avoided (despite rumors to the contrary, "Wikipedia is not a forum"), I wonder if it might be related to the sound of running water. Perhaps its an instinctual reaction to rain storms and/or rushing water and the like? While an adult dog can usually deal with a small stream, generally a puppy could not.  —71.20.250.51 (talk) 05:32, 30 September 2014 (UTC)

I dunno. I've both owned and seen puppies that have a lot of fun with the stream coming out of a hose. I don't think it's a species-wide thing. Justin15w (talk) 14:16, 30 September 2014 (UTC)

Volcanism of Io

Earth's volcanism is powered by radioactive decay, while Io's volcanism is powered by tidal effects from Jupiter's gravity. Since energy is drawn from the Jupiter-Io system, can it cause orbital instability? If so, when will Io fall into Jupiter? Also, can humans tap Io's volcanism as a source of energy? Jayakumar RG (talk) 17:30, 30 September 2014 (UTC)

The article on Volcanism doesn't say anything about radioactive decay. What's your source for that? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:51, 30 September 2014 (UTC)

I learnt it elsewhere, but it is mentioned in the Volcanology of Io article. The presence of magma beneath the earth's surface is because of heat generated from radioactive decay.

You might be interested in reading our article Volcanology_of_Io. SemanticMantis (talk) 19:28, 30 September 2014 (UTC)

Thank you, the article is extremely informative. But it says nothing about orbital instability. Jayakumar RG (talk) 01:18, 1 October 2014 (UTC)

It is for that reason that I directed you to Galilean_moons#Members yesterday, User:Jayakumar RG. The article has references for further reading. μηδείς (talk) 04:12, 1 October 2014 (UTC)

• The Galilean moons also orbit in various whole number or fractional resonances. This might affect any orbital change or decay. μηδείς (talk) 23:35, 30 September 2014 (UTC)

• The orbits of moons do indeed decay as a result of tidal forces, although over billions of years, so the differences may not be that noticeable before the Sun dies. And the result seems to be that they move into further orbits and would theoretically eventually break free, at least in the case of our Moon. StuRat (talk) 21:43, 1 October 2014 (UTC)

• You're looking at a two-body system. In a two-moon system, like Mars, the inner moon will crash, and the outer moon will escape. A recent version of the Theia hypothesis includes a two-moon system. In a multiple body system the resonances (see Bode's law) appear to enhance stability. Studies for the 90's seemed to imply that the 8 major planets have stable orbits, while Pluto's orbit is only stable over a much shorter period. What happens if Pluto enters the inner solar system is unpredictable and a subject of chaos theory. Given that the three inner Galilean moons have a 1::2::4 resonance, their interaction seems stabilizing, not destabilizing. μηδείς (talk) 01:31, 2 October 2014 (UTC)

Bumpers on motor vehicles

When and why did manufacturers of (some) motor vehicles discontinue the practice of equipping them with bumpers? I did not find answers in the article "Bumper (automobile)".
—Wavelength (talk) 20:54, 30 September 2014 (UTC)

Can you give an example make/model/year? In the USA, bumpers are required for all passenger vehicles, and there is a set of safety standards that the bumpers must meet. See e.g. here from the NHTSA [2]. Certain non-passenger vehicles are exempt from those regulations, and "some vehicles do not have a solid bumper across the vehicle, but meet the standard by strategically placed bumper guards and corner guards". So perhaps you are seeing vehicles with a sort of "disguised bumper", i.e. one which meets the regulations for bumpers but doesn't have a highly visibly separate piece of metal? SemanticMantis (talk) 21:21, 30 September 2014 (UTC)

First I heard someone mention it, and later I saw some in a printed advertisement. From a Google Image Search for "2015 ford", I found this image.

—Wavelength (talk) 22:07, 30 September 2014 (UTC)

That car has bumpers. They are covered by a plastic panel Greglocock (talk) 22:49, 30 September 2014 (UTC)

Dude, Where's My Bumper?

The Audi R8 is an example where the function of a "bumper" is integrated internally, with no conventional bumper visible.→

71.20.250.51 (talk) 23:38, 30 September 2014 (UTC)

I asked this question to myself many many many years ago. The bumper article says:

Cars were equipped with bulky, massive, heavy, protruding bumpers to comply with the bumper standards of the 1970s and early 1980s. By the late 1980s most bumpers were concealed by a painted thermoplastic fascia. The thermoplastic currently in use is a combination of polycarbonate and acrylonitrile butadiene styrene called PC/ABS. The internal aspect of the bumper usually consists of a lightweight foam or polyurethane. This foam does not contribute to the impact absorption factor of the bumper, but serves as a filler and prevents the thermoplastic fascia from cracking upon impact.

Cars always have bumpers. They are always useful. It's just they are not concealed. They do not use beautiful and big chrome plated bumpers anymore. -- Toytoy (talk) 03:19, 1 October 2014 (UTC)

Like my car

I drive a car similar to this. Where are the bumpers? Don't say behind the plastic bar because there is nothing there except the radiator. Not all cars have bumpers because bumpers are no use whatsoever in a road traffic incident above about 20 mph. Richard Avery (talk) 11:54, 1 October 2014 (UTC)

Not all motor vehicles have bumpers because not all vehicles are classified as "passenger cars" by the NHTSA for the purposes of bumper laws. If you read my link above, you'll see that SUVs and light trucks are not regulated by the law that applies to "normal" cars. You'll also see that the intent of the laws is to prevent damage to the vehicle in low-speed collisions, and has nothing to do with passenger safety or higher speed collisions. I'm not sure, but I suspect your vehicle might not be classified as a passenger car for the purposes of bumper laws in the USA. SemanticMantis (talk) 13:08, 1 October 2014 (UTC)

Just for the record: an Audi R8 is typically not classified as a light truck or SUV. If somebody will lend me one, I'll check to make sure.  —71.20.250.51 (talk) 07:01, 2 October 2014 (UTC)

Indeed, I was speaking of the Nissan pictured below the Audi. I'm not sure how it falls with the NHTSA, but I think it's considered something like a "mid-size SUV" for advertising purposes. SemanticMantis (talk) 14:32, 2 October 2014 (UTC)