Wikipedia:Reference desk/Archives/Science/2016 November 19

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November 19

Bacterium or Virus that actively infects both a Plant and an Animal?

I am aware that certain fungi can infect both plants and animals, as in the case of aspergillosis. Is there either a bacteria or a virus that actively infects a host from both the Plantae and the Animalia? I am not talking about something like food poisoning caused by vegetation handled under unsanitary conditions, but an agent which actually causes disease symptoms in bot a plant and an animal, especially in humans. μηδείς (talk) 01:05, 19 November 2016 (UTC)

The bacterium Pseudomonas aeruginosa does. From the article, "In higher plants, P. aeruginosa induces symptoms of soft rot, for example in Arabidopsis thaliana (Thale cress) and Lactuca sativa (lettuce). It is also pathogenic to invertebrate animals, including the nematode Caenorhabditis elegans, the fruit fly Drosophila and the moth Galleria mellonella. The associations of virulence factors are the same for plant and animal infections". In humans it is "An opportunistic, nosocomial pathogen of immunocompromised individuals, P. aeruginosa typically infects the airway, urinary tract, burns, and wounds, and also causes other blood infections." --Modocc (talk) 02:19, 19 November 2016 (UTC)

Very interesting. I knew of Pseudomonas as an opportunistic infectious agent, but thought it was a fungus. Its mode of action seems analogous to types of fungi which are generalized omnivores.

I am curious if there is a more specialized pathogen, that attacks, for examples, cacti and birds which nest in them, or marine iguanas and the algae they eat? μηδείς (talk) 04:02, 19 November 2016 (UTC)

When Worlds Collide

In When Worlds Collide (1951 film), as the rogue planet approaches on its collision course with Earth, but before it hits, Earth experiences earthquakes, volcanic eruptions, and tsunamis. Is there a reference that discusses whether these things would really occur, and if so to what extent based on the mass of the rogue planet? Loraof (talk) 03:51, 19 November 2016 (UTC)

Such events would be caused by tidal forces. In extreme cases, tidal effects can do a lot more than just move water around a few meters. It is thought that tidal effects between some planets and their moons cause quakes and volcanoes, and in theory tidal effects could get strong enough to tear a planet to pieces. See also roche limit, which includes formulas used to approximate how close two objects of known composition can get before one is torn apart. Someguy1221 (talk) 04:15, 19 November 2016 (UTC)

The question comes up if the planets would be close enough, for long enough, to show substantial tidal effects. If they were headed straight towards each other at high speed, maybe not. Of course, this is quite unlikely. A near-miss is far more likely, and there tidal effects could be the main problem (although a change in Earth's orbit wouldn't be good, either). StuRat (talk) 04:24, 19 November 2016 (UTC)

The tidal effect is proportional to the other body's mass divided by the cube of its distance. —Tamfang (talk) 18:35, 19 November 2016 (UTC)

To show the importance of time, tidal heating may generate significant heating of the magma within the Earth, but it would take time for that magma to make it's way to the surface and erupt as volcanoes. StuRat (talk) 19:19, 20 November 2016 (UTC)

@Loraof: See Earth tide. The relatively small and distant Moon causes the surface of the Earth to rise and fall by more than a foot, as I understand it. The Sun has an effect on the same order of magnitude. As a planet approaches, its gravity increases per the inverse square law, just as does its visible size. I haven't gone over the math, but looking at tidal force the effect seems to be proportional to M/R^3 - in other words, an object of the same density should exert the same tide when it is the same size in the sky, no matter how near or far it is - thus the Sun exerts less tidal force than the Moon because its density is 0.255 that of Earth while the Moon is 0.606 that of Earth; if they were the same density, I think their tides would be the same. So I haven't watched the movie, but if they show the planet and the moon in a frame, you can say how much more the planet's tide should be than the Moon's at any given time (assuming it is not more than maybe twice as dense). The effect, of course, of subjecting the Earth to a stronger tide than the Moon's, or even one weaker that is added, is completely unknown - fortunately we have no data - we certainly can guess that it might stress faults that are already near rupture, causing earthquakes and tidal waves, and possibly disturbing magma reservoirs at volcanoes geologically close to eruption. The effects, as noted above, grow progressively worse... Wnt (talk) 13:50, 23 November 2016 (UTC)

Very helpful--thanks! Loraof (talk) 16:00, 23 November 2016 (UTC)

Induced coma and general anaesthesia

What's the difference between an induced coma and general anaesthesia?Llaanngg (talk) 13:23, 19 November 2016 (UTC)

Barbituates. --Jayron32 16:30, 19 November 2016 (UTC)

Yes, but is the state of the brain in each case somehow different? Or are they the same, but induced through different means (barbiturate vs. opioid)? The induced coma article claims that it is a "a deep state of unconsciousness" and the General anaesthesia one claims it's a "state of unconsciousness." How much weight should we put on the 'deep' here? Is this just an careless way of expressing it? Or does it imply that there are different levels of unconsciousness, and induced coma is a deeper one. Both the articles about induced coma and Unconsciousness are quite short.--Llaanngg (talk) 00:53, 20 November 2016 (UTC)

Judging just from a look at the articles, it looks to me like in an induced coma the object is to achieve flatline EEG, while regular anesthesia just aims for a satisfactory level of unconsciousness. The articles could benefit from some expert attention. On a side note, opioids produce analgesia, not anaesthesia. If you are administered enough opioids to cause a loss of consciousness you'll probably die of an overdose without treatment. The anaesthetics are other drugs, such as propofol and the inhaled anaesthetics. --02:43, 20 November 2016 (UTC) — Preceding unsigned comment added by 47.138.163.230 (talk)

I think it's helpful to look at the roots of words. Anesthesia means literally "loss of sensation". It's also a given that pain-killing will also occur (as pain is a sensation) as well as unconsciousness (with general anesthesia). "Coma" means literally "deep sleep". So if a procedure is to cause loss of sensation (e.g. an op) then it's referred to as anesthesia. If its merely to induce deep unconsciousness for other reasons it can be referred to as an induced coma. --Jules (Mrjulesd) 17:53, 20 November 2016 (UTC)

The article at General anaesthesia (note subsection) implies that a coma would refer to a deeper state of unconsciousness, but it is not referenced. I also haven't found anything solid out there that spells it out, despite there being several other people asking the same question. Matt Deres (talk) 02:05, 21 November 2016 (UTC)

Naming of human settlements in the U.S.

How is a human settlement on United States territory officially called? In my opinion, it is "name of setlement, state". Example: Ramona, California. In human settlements of the Insular areas of the United States another Sufixes are in use. Example: Charlotte Amalie, U.S. Virgin Islands. --Mattes (talk) 20:36, 19 November 2016 (UTC)

Charlotte Amalie, U.S. Virgin Islands is correct. Loraof (talk) 01:24, 20 November 2016 (UTC)

• That's not another suffix, the two forms are perfectly analogous. —Tamfang (talk) 08:13, 21 November 2016 (UTC)