Wikipedia:Reference desk/Archives/Science/2020 August 23

= August 23 =

Pollen - living
The topic on bioaerosols says pollens are non-living but they carry the male gametophyte so how can they be considered as non-living? — Preceding unsigned comment added by Jhame99 (talk • contribs) 07:18, 23 August 2020 (UTC)
 * They don't have any metabolism right? 2601:648:8202:96B0:0:0:0:DDAF (talk) 07:21, 23 August 2020 (UTC)
 * Endospores have no significant metabolic activity either, yet are generally not considered to be dead. Since they can germinate and thus be responsive to their environmental conditions, some activity must be going on, however reduced its level, and indeed, not entirely surprisingly, some studies have found indications of metabolic activity. The same applies for pollen. I do not see where the source cited for this claim in the Bioaerosol article states that pollen are non-living. --Lambiam 08:39, 23 August 2020 (UTC)
 * The article on Pollen says If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule (...). This is a shape development, which is one of symptoms of life, I suppose. --CiaPan (talk) 10:39, 23 August 2020 (UTC)
 * So do you concur in the judgement that the death certificate issued by the Bioaerosol article is premature? --Lambiam 18:19, 23 August 2020 (UTC)
 * I have removed the statement. Some medical book probably put a list together showing pollen in the non-living column in the sense that it isn't bacteria but it is an allergen, and some user on Wikipedia then over-generalized. Abductive  (reasoning) 08:37, 24 August 2020 (UTC)


 * The problem with the initial question is explained well a Life, which states "The definition of life has long been a challenge for scientists and philosophers, with many varied definitions put forward." The problem is, when you say "Is XXXX alive" or "Is XXXX life", you are faced with the problem that "life" and "alive" and all of the words related to them have multiple related meanings which don't always line up 100% of the time.  Sometimes you mean "Is this thing part of the greater processes of "life" writ large" and sometimes you mean "Is this individual thing capable of living on its own" and sometimes you mean "Has this thing died or not" and sometimes you mean... Well, you get the idea.  "Is pollen living" can be answered with either "yes" or "no" depending on which particular nuanced definition of "living" you are working with.  Clarify what you want to ask first, then decide if pollen is living.  Is it actively consuming energy from its environment to support its life processes?  If that's what you require for "living" than no, it isn't.  Is it part of the process of life, and not the end of it?  If that is your definition for "living", then yes it is.  -- Jayron 32 11:36, 24 August 2020 (UTC)
 * This sounds like criticism of the formulation of the question, but I think the OP was fully justified in asking how the statement of pollen being non-living can be reconciled with pollen grains carrying gametophytes, which are alive under any modern definition of "life". --Lambiam 08:31, 25 August 2020 (UTC)
 * Yes, they are justified in asking their question. Such pollen grains would be considered "alive" under nearly all definitions I can think of, which is I think why they were confused.  As stated above "Endospores have no significant metabolic activity either, yet are generally not considered to be dead. Since they can germinate and thus be responsive to their environmental conditions, some activity must be going on, however reduced its level, and indeed, not entirely surprisingly, some studies have found indications of metabolic activity. The same applies for pollen. I do not see where the source cited for this claim in the Bioaerosol article states that pollen are non-living."  That seems like a reasonable answer to their question to me.  Also see the answer below, "A grain of pollen is actively running maintenance operations to stay alive. Typically pollen is viable (means "alive") for a few hours or days. Example scientific article. Then it dies, from drying out, exposure to ultraviolet, or running out of sugar, etc." Both of those answers and their sources make it clear that pollen is alive, under most definitions of the term.  -- Jayron 32 16:06, 25 August 2020 (UTC)
 * A grain of pollen is actively running maintenance operations to stay alive. Typically pollen is viable (means "alive") for a few hours or days. Example scientific article. Then it dies, from drying out, exposure to ultraviolet, or running out of sugar, etc. Abductive  (reasoning) 21:15, 24 August 2020 (UTC)
 * Exactly. -- Jayron 32 08:25, 25 August 2020 (UTC)

combination window fan and air filter
Because of heat and coronavirus I was thinking of installing a window fan to blow outside air into the room; but because of the California wildfires, the outside air around here is full of smoke. Weirdly though, the only air purifiers I can find sit inside the room, pull in air, filter it, and blow it back out. I can't find any designed to install in a window so the (dirty) intake is on one side and the clean exhaust is on the other. I did find a few aftermarket filters on amazon to put on a box fan but I wonder how effective they are, and if the fan motor would be strained by the unexpected extra load. Any advice? Maybe I could use a furnace filter over the window fan, to prefilter the air before using the indoor purifier to get the rest of the particles out. Thanks. 2601:648:8202:96B0:0:0:0:DDAF (talk) 07:20, 23 August 2020 (UTC)
 * Amazon search: "Fan + Filter" turns up the EcoBreeze 2. 97.82.165.112 (talk) 11:27, 23 August 2020 (UTC)
 * Do you mean this? It does look interesting, though expensive.  Thanks. 2601:648:8202:96B0:0:0:0:DDAF (talk) 16:17, 23 August 2020 (UTC)
 * In my experience and that of others I've heard about this from, box fans aren't usually damaged by having filters added (and a domestic fan should be thermally protected, so it'll stop before causing a fire if it overheats), but the airflow will be greatly reduced due to the fan being designed for use in free air. If you can find a used furnace fan and build some kind of enclosure for it, that'll pull or push air through a filter much more effectively. (It might or might not be thermally protected, but it's probably less likely to overheat in the first place. And furnace fans actually run better with some resistance to flow, such as that provided by a filter.) Instructables and YouTube both have lots of air cleaner projects based on box fans and furnace fans. Another improvement you could make, if your fan can handle the increased pressure drop, is to put a washable cloth filter (e.g. a bedsheet) or an inexpensive disposable filter (e.g. a layer of blue workshop paper towels) before the furnace filter, so that the expensive filter lasts longer before needing to be replaced. ← PointyOintment ❬t &amp; c❭ 16:03, 25 August 2020 (UTC)


 * Caution: original research ahead -- We fabricated something quite awhile ago, (literally from spare parts) when temporarily converting a garage into a automotive paint booth, needing ventilation that had to be dust free. We took a VW fan, with generator  attached (not alternator), reversed polarity so that it became a motor.  Then attaching a washable (Chevy-type) air filter directly to the fan intake.  It worked great -- the centrifugal force from the spinning filter helped keep it clean. Anyway, there are many ways to Jerry-rig something (like simply attaching an HVAC HEPA filter to a standard window fan).  107.15.157.44 (talk) 03:25, 26 August 2020 (UTC)