Wikipedia:Reference desk/Archives/Science/2018 July 31

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July 31[edit]

croaking frog stopping[edit]

1. Is 'croaking' sound by a single frog possible or is that always in chorus or group? 2. Will that croaking sound stop momentarily when someone crosses closely to a croaking frog? Thanks.

1 dunno 2 yes. At least in Australia. Greglocock (talk) 12:27, 31 July 2018 (UTC)[reply]
It will depend on the species, though there is much commonality in the behavior. For example, when I've encountered the American bullfrog, as it is rather large, the number of individuals in a chorus tends to be small, so I've certainly heard one forlorn bullfrog calling without apparent response at first. As that article says, "choruses are dynamic", which is to say, they have to start (and end) somewhere. My experience with frogs going silent is that it seems to be based on line of sight; I've stood just on the far side of a barberry bush and listened to a chorus of wood frogs clucking away, but often frogs will go silent even from 20 or 30 feet distant if they see me. Wnt (talk) 12:46, 31 July 2018 (UTC)[reply]
Yes and yes. Frog#Call has "Males may call individually or there may be a chorus of sound where numerous males have converged on breeding sites." A tree frog found its way into my house a few years ago and sang quite a bit all by itself. (No citation for the answer to the second question, but I have observed it hundreds of times.)--Wikimedes (talk) 05:10, 2 August 2018 (UTC)[reply]

Shark in bleach solution[edit]

In this story it refers to the shark being put in a bucket with a bleach solution.

I couldn't work out whether this was supposed to be amateurish/cruel (a bucket that's previously been used for cleaning, filled with water) or clever/pre-planned (a bucket deliberately filled with a liquid a shark would be comfortable with).

I suspect the former (surely bleach harms most creatures?) but am unsciency enough (I refer you to my last use of brackets) to recognise it may be the latter.

Which is it? --Dweller (talk) Become old fashioned! 14:05, 31 July 2018 (UTC)[reply]

You've presupposed intent with regard to the bleach solution, which is not evident from the text. An equally likely explanation is that the people who stole the shark grabbed a random bucket, which had previously been used to mop a floor with, and thus contained a bleach solution, threw the shark into it, and attempted to walk out. Nowhere in the article does it state that the couple intentionally used bleach or even knew the bucket contained the bleach. It's always good to make the fewest assumptions possible, and to not explain things which are themselves not established as true first. See Occam's razor. --Jayron32 14:09, 31 July 2018 (UTC)[reply]
I thought I had that covered with "amateurish ... a bucket that's previously been used for cleaning, filled with water" but if by including "cruel" (I think stupidity/lack of deliberate malice doesn't necessarily make things not cruel) I didn't make it clear enough, that was indeed one of the two options. --Dweller (talk) Become old fashioned! 14:17, 31 July 2018 (UTC)[reply]
Why yes you did. My apologies for not reading your question more carefully. I was rude, and for that I apologize. --Jayron32 15:12, 31 July 2018 (UTC)[reply]
And now you were lovely and for that I'm very grateful. :-) --Dweller (talk) Become old fashioned! 15:37, 31 July 2018 (UTC)[reply]
Here's a news article from (sort-of-) local news channel NBC 5 Dallas/Ft. Worth: Horn Shark Found After Being Stolen From San Antonio Aquarium, including a lengthy interview video with the local police. Describing the shark's health and condition: "...Luckily, the thief was somebody who knew what he was doing..." according to Leon Valley Police Chief Joseph Salvaggio. The police chief declined to discuss questions that were specifically about the bleach solution.
Here is more coverage from KSAT San Antonio: Shark stolen from San Antonio Aquarium is rescued.... "Spellman (General Manager lf the San Antonio Aquarium) said that the bleach solution the shark was placed in might have shocked the shark's system, which made aquarium staff and authorities uncertain if the shark would survive the heist. But, to the surprise of police and aquarium staff, the shark was in good health when it was returned Monday night."
Nimur (talk) 14:21, 31 July 2018 (UTC)[reply]
The CNN version of the story is kind of oddly worded, but I inferred that they had dumped the bleach first.[1] ←Baseball Bugs What's up, Doc? carrots→ 15:00, 31 July 2018 (UTC)[reply]
Great detective work, Bugs. Curious stuff. I love this: "The police chief declined to discuss questions that were specifically about the bleach solution.". I'm going to stick with amateur/unintentionally cruel for now. --Dweller (talk) Become old fashioned! 15:39, 31 July 2018 (UTC)[reply]
  • There are various kinds of bleach. I think a chlorine bleach such as Clorox is going to be harmful to just about any living thing. However, oxygen bleaches such as OxiClean are relatively nontoxic if the concentration isn't too high, and might even provide some oxygen to the shark. Looie496 (talk) 16:29, 31 July 2018 (UTC)[reply]
The first story I remember seeing said that the thieves "emptied out a bleach bucket".[2] When covering a current event on Wikipedia, I always try to get the first story I can find because it is the most detailed and comprehensible - after that there are a thousand glommers-on that just garble the facts. But it gets harder and harder to find them because the news spammers get better at making it look like they published the story last March. Anyway, I would assume that they not merely emptied out the bleach bucket, but rinsed it also. Wnt (talk) 19:11, 31 July 2018 (UTC)[reply]

Apollo 11 splash down module[edit]

Apollo CM

My son has seen a LEGO model of the Saturn V rocket. The module that splashed down is faithfully recreated in the LEGO. My son would like to know what the 3 ball shaped objects are at the top of the module and why there isn't a 4th one. A simple schematic diagram that is comprehensible to a child would be peefect, text is fine too. --Dweller (talk) Become old fashioned! 21:10, 31 July 2018 (UTC)[reply]

See Apollo Command Module#Earth Landing System. The Command Module contained "three inflation bags for uprighting the capsule if necessary"; I suppose that they had to be asymmetrical (three bags rather than four) to successfully turn the module over in the water (i.e., to float only one side of the module). In the Apollo 11 mission they had to be used to right the module after splashdown, and that's why they are deployed in the photo you linked. Deor (talk) 22:04, 31 July 2018 (UTC)[reply]


Technical details can be found in the Apollo Spacecraft News Reference book, Section 12 - Earth Landing Subsystem, written by North American Rockwell circa 1972 as a reference encyclopedia for news and media reporters who wanted to cover factual data about the Apollo missions. Page 96 has some great diagrams of the CM Uprighting System with the infamous "Stable II" diagram and the center of gravity for the capsule.
This information was easily discoverable from the main Apollo Lunar Surface Journal website, the official online NASA record of the lunar surface operations. I recommend reading the ALSJ early and often.
For any interested rocket scientist/nautical-engineering nerds in our audience: the difficult calculation of the metacentric height or "righting arm" problem is a recurring theme in the design of control systems for spacecraft (and boats). In the same way that control system engineers calculate a phase margin during the analysis of control system stability, nautical engineers calculate an equivalent property that directly corresponds to the geometric phase angle of a rocking vessel.
Failure to engineer an acceptable phase margin - and failure by the captain to account for stability margin degradation during severe icing conditions - was the cause for the Destination tragedy that recently made the front page of the NTSB's Major Investigations website. "The NTSB’s Marine Accident Brief 18-14 states the probable cause for the sinking was the captain’s decision to proceed during heavy freezing spray conditions without ensuring the vessel had a margin of stability to withstand an accumulation of ice..."
This is all just a fancy way to say that "it tips over in the water because it's not balanced correctly;" but when engineers say it, they do it with technical diagrams and equations and heel angle charts that account for the distribution of weight and loading on the interior of the vessel, in all orientations. This is all great reading material for your Lego-infatuated future astronaut - especially if they plan to keep the minifigs safe during the mission! Never forget the important lessons standardized in NASA Handbook 8709.24 - "Promote and sustain a strong safety culture at all levels of the Agency"!
Nimur (talk) 00:26, 1 August 2018 (UTC)[reply]
Yes, the Apollo Command Module could be nose down after spashdown (called "stable 2 position". The bags inflate to right the spacecraft. It looks like there was some stuff that prevented having four bags, but the photo I added only seems to have two. Bubba73 You talkin' to me? 01:22, 1 August 2018 (UTC)[reply]
There are only two visibly-inflated bags because your photo is the Columbia (the CM from Apollo 11), photographed in its present museum set-up, which - for historical and educational purposes - is recreating the famous Stable 2 with Only Two Flotation Bags Inflated situation that occurred on July 24, 1969. Here's the transcript for ALSJ Apollo 11 - Reentry.
Meanwhile the astronauts were inside, safely strapped in, upside down, politely completing their checklists and waiting for Air Boss to order the swimmers into the water. Nobody ever said it was easy to go From the Earth to the Moon, Around the Moon, and return to Earth again!
Nimur (talk) 02:52, 1 August 2018 (UTC)[reply]

This is great stuff, thank you very much. --Dweller (talk) Become old fashioned! 16:54, 1 August 2018 (UTC)[reply]

The Orion capsule following its 2014 test mission, where only two of its five airbags worked properly.
Your son may also be interested in learning that a similar crew module uprighting system is used on Orion, the capsule NASA is currently developing for an eventual return to the vicinity of the Moon. Orion (a larger capsule than Apollo) uses five airbags, but during its 2014 flight test only two of the five functioned properly, with one airbag failing to inflate and two failing to hold pressure. [3] In 2017 NASA tested the redesigned system under a number of failure modes, and this post shows a capsule rolling upright under four inflated airbags. -- ToE 22:35, 1 August 2018 (UTC)[reply]

Antifungal cream[edit]

Today I ran across a tube of antifungal cream that I'd bought some time ago, and I glanced over the ordinary warnings and how-to-use directions. I was surprised to see a note this product is not effective on scalp or nails. Fingernails I can understand, since they're structurally a good deal different from soft ordinary skin. But from the perspective of a fungal infection, how is the scalp so different from ordinary skin that clotrimazole is unable to treat the infection effectively? Google has pages on how to handle scalp fungus, but no explanation. I ran a quick Medline search, and I saw a couple of articles (DOI 10.1002/14651858.CD008138.pub3 and al-Fouzan, A.S., et al. "Dermatophytosis of children in Kuwait : a prospective survey". International journal of dermatology 32.11 (1993): 798-801.) that seem to conclude that topical use of clotrimazole was better than placebo at treating fungal infections of the scalp, so I'm even more confused. Nyttend (talk) 22:23, 31 July 2018 (UTC)[reply]

It's interesting, yeah. Even clinical trials I could find on clotrimazole going back to the 70s, at least the larger ones, actually excluded nail and scalp infections from their patient groups. I suspect this might be due to griseofulvin being an older drug that is proven both safe and effective for these cases. That is, it is relatively unusual for a patient to present with a scalp fungus that cannot be adequately treated by the standard of care, so unless you really enrich for such patients, it's tough for a proposed trial to pass review. In this small clinical trial, griseofulvin was compared to itself plus clotrimazole against a scalp fungus, and no significant improvement was found (though simultaneous treatment with selenium sulfide appeared to hasten the elimination of viable spores). Someguy1221 (talk) 22:36, 31 July 2018 (UTC)[reply]
Yes, for regulated drugs, the labeling has to follow the relevant laws and regulations. In most jurisdictions with meaningful regulation of drugs, drug labels can't claim uses for anything not approved by the regulator. So it might simply mean the drug has not been approved for nail or scalp infections. If it's still effective, the label can't tell you that, but in most places medical professionals can prescribe it to you off-label. The lack of approval is often because of a lack of incentive for anyone to go through the rigors of the drug approval process for a new indication. A big example is aspirin. Even though we know it's very useful for prevention of cardiovascular disease, at least in the U.S., you won't find that on the label of any aspirin product, because it hasn't been approved by the FDA for that use. Hence, all use of it for anything other than pain relief is off-label use. --47.146.63.87 (talk) 07:59, 1 August 2018 (UTC)[reply]
I mostly agree with you but I'm not sure if your statements on aspirin are entirely correct. See [4] [5] (maybe also [6]) [7] [8] [9]. As I understand it, the FDA has approved the use of aspirin for secondary prevention of cardiovascular disease i.e. in those who have already experience a cardiovascular event. They have not approved it for primary prevention. Also the information on usage for secondary prevention is only targeted at health professionals. So using aspirin for secondary prevention under the guidance of a doctor or other professional is not off-label. Using it for primary prevention would be, even I think with many indications/known risk factors e.g. family history, age, diet, exercise and whatever else which may lead to many professionals recommending it. Nil Einne (talk) 18:03, 1 August 2018 (UTC)[reply]
Oh hey, interesting. I wonder if the FDA standards are different for what can be stated in things for medical professionals as opposed to the general public. --47.146.63.87 (talk) 02:32, 2 August 2018 (UTC)[reply]
The laws that regulate drug advertisement are very complicated, at least in the USA; our regulatory agency, the FDA, has "different ways to enforce the laws." Here's a lengthy FAQ website, including answers to How can an ad violate the law?
"Prescribing information"... "is written for healthcare providers"; certain types of advertisement only need to contain a "Brief Summary", which is "...the technical name for the detailed information that appears in ads for prescription drugs." Both types of information are regulated by FDA.
Nimur (talk) 06:58, 2 August 2018 (UTC)[reply]
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