Wikipedia:Reference desk/Archives/Science/2018 May 21

= May 21 =

Entamoeba coli
According to its article, E. coli "usually...is immobile, and keeps its round shape". How does the thing consume nutrients? I was under the impression (wrongly, apparently) that all amoebae consumed food by surrounding it and basically engulfing it, but that doesn't work if one doesn't move and doesn't deviate from a round shape. The article's almost entirely focused on the amoeba as the source of diseases of various sorts and says almost nothing about the species itself, as if our article on lion talked almost entirely about people getting attacked by lions and basically didn't address the animal's life cycle. Nyttend (talk) 02:48, 21 May 2018 (UTC)
 * "Keeps its round shape" is only sort of true, in a "compared to what" sort of way. It does form pseudopods, and is capable of phagocytosis. I have a feeling this may be a bad paraphrase of info here: "Motility: visible only in fresh, unfixed stool specimens. The trophozoite slowly forms a pseudopod, then withdraws it and remains immobile maintaining a round shape. After a few moments, a new pseudopod forms in a new position, and so on. The result is an anarchic, sur place (non-progressive) movement, without a defined direction. In some cases, it is possible to observe the simultaneous, explosive formation of 3-5 small, rounded pseudopods extend simultaneously, but even in this case the amoeba remains within the microscopic field." - Nunh-huh 03:12, 21 May 2018 (UTC)
 * Unrelated to this discussion, I wonder if there is any source that uses Escherichia coli and Entamoeba coli in the same work. Both of them can be written as E. coli. SSS (talk) 16:03, 21 May 2018 (UTC)
 * It is inconvenient. - Nunh-huh 04:05, 22 May 2018 (UTC)

Hands are always cold
My mom's hands are often cold during the colder days but warm on warmer days. It makes me ask if there's some people's hands that are never that warm, or rather always dependent on the temperature of the surroundings, no matter what time of year is that? Planet Star  05:11, 21 May 2018 (UTC)
 * Although this is borderline asking for "medical advice" -- which we cannot provide (see this page's header), here is a reference from a reliable source: . —2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 06:16, 21 May 2018 (UTC)

Pressurized water reactor and boiling water reactor fuel pin
The fuel pin outer diameter in BWRs is 12.5 mm however, it is 9.5 mm in PWRs, why? I guess it has to do something with CHF (critical heat flux) but not able to correlate totally.14.139.124.180 (talk) 14:06, 21 May 2018 (UTC)
 * "CHF" = ? —2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 18:19, 21 May 2018 (UTC)
 * Presumably Critical heat flux (the only relevant topic listed on our CHF page:) DMacks (talk) 19:58, 21 May 2018 (UTC)
 * "CHF" refdesk trifecta in play! See . DMacks (talk) 02:29, 22 May 2018 (UTC)