Wikipedia:Reference desk/Archives/Science/2014 December 19

= December 19 =

Did anyone ever make a weird mathematical treatment of physics with extra dimensions of time?
Where every possible spacetime really exists, more than that universes just like ours except one electron was on the other side of the electron cloud at 10^61 Planck times exist (if you even looked at it at the wrong time (slightly before 10^61), you couldn't distinguish the universes anyway, even in theory, it's almost not even a different universe). Of course people make weird unfalsifiable, Occam's Law-violating or even debunked physics theories all the time, a theory existing doesn't mean that it deserves serious thought. Sagittarian Milky Way (talk) 00:30, 19 December 2014 (UTC)


 * Imaginary time. μηδείς (talk) 01:21, 19 December 2014 (UTC)


 * OK...the title here is a question - the answer to which is "Yes...several versions of String theory suggest multiple time dimensions." The rest is not.  But to comment on what you have to say:
 * Certainly if the Many worlds interpretation of quantum theory turns out to be true, then many universes are seemingly (or actually) completely identical. There is no problem with that - if a quantum-mechanical event causes a universe to split into two parallel paths, then one of them can go on to have another event that perfectly undoes the first one - and now you have a pair of parallel universes that are utterly identical.  This causes no specific problems - if the hypothesis is true, then there would be vastly more universes than there are atoms in our universe - there would be no shortage of them and no 'cost' to creating new ones.  We could even imagine that there are an infinite number of them.
 * Isn't the many worlds universe be more like an "exploding cone-time" where the Big Bang is a point, BB+1 Planck time is x wide, the third Planck time is x*x wide, the fourth Planck time is x*x*x wide and so on? That is not usually what two dimensions means. In 2-D time with perpendicular axes the Big Bang would be a line at the left edge and universes that won't split from ours for trillions of years would start already separated. Sagittarian Milky Way (talk) 18:11, 19 December 2014 (UTC)
 * The many worlds hypothesis may very well be unfalsifiable. We define "the universe" as "all of spacetime and everything that exists therein, including all planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy."  So anything we could detect or measure about these "parallel universes" would make them be a part of our universe.  So by the very definition of the word "universe", anything that happens in a different one in undetectable.   For this reason, the many worlds hypothesis must seemingly be unfalsifiable.  That doesn't mean that it's "false" - it just means that we may never be able to prove or disprove it.
 * Occam's Razor isn't a "law" - it's not even a hypothesis - and it's not always true. It's just a handy guide that you can employ when there are many possible explanations for something and you want to pick the most likely one.  So, if I can't find my TV remote, it might have fallen behind the sofa cushion, or it might be that a team of crack commandoes from North Korea may have broken into my home and removed the remote just to be really REALLY sure that I can never watch "The Interview".  In terms of the science, I may not be able to decide which of those hypotheses are true right now...but Occam's razor suggests that I should probably do the experiment of looking behind the sofa cushion BEFORE I contact Homeland Security.  It should be called "Occam's Very Rough Rule of Thumb" or something.
 * I hardly gave any thought whatsoever while writing those two words, if I knew that wasn't a common name for the idea then I wouldn't bothered to Google Occam. I knew it wasn't utterly unable to be wrong. Sagittarian Milky Way (talk) 18:11, 19 December 2014 (UTC)
 * A "theory" (the scientific term, meaning something that's proven and widely accepted) does deserve serious thought. Most useful hypotheses (thing that we think are good explanations, but are not yet proven) are sometimes worthy of serious thought - and sometimes not.  Many Worlds is a pretty good hypothesis that could certainly explain bizarre stuff like Schrödinger's cat - and is taken seriously by many reputable physicists.  So I think it does deserve serious thought, even though it's not proven, may never be proven, and may very well be unfalsifiable.
 * But physics "theories" (in quotation marks) go all the way to "the sun is made of iron" and Time Cube. Even if no one with a degree in a relevant field takes it seriously (note that I didn't say that's the case) it might be easy enough to add the terms needed to make Einstein's theory 3+2 dimensional (I haven't studied the equations, I can't tell) but have little enough physics sense to take it seriously. Sagittarian Milky Way (talk) 18:11, 19 December 2014 (UTC)


 * Is it possible that stored memory could be misinterpreted as another time dimension?165.212.189.187 (talk) 16:43, 19 December 2014 (UTC)
 * No. -- Jayron 32 18:37, 19 December 2014 (UTC)


 * One recent proponent is Itzhak Bars who had an article in New Scientist some years ago. We have an article Multiple time dimensions. I remember reading a discussion of likelihood of multiple time dimensions in a popular science book (i.e. if there are Compact dimensions are they spacelike or timelike or both) a while ago, possibly The Road to Reality by Roger Penrose? JMiall  ₰  10:59, 20 December 2014 (UTC)

Is the heart's valves made of cartilage?
I read the articles here and eventually I don't understand if yes or not149.78.45.16 (talk) 02:53, 19 December 2014 (UTC)


 * No. See cartilage and heart.--Shantavira|feed me 12:03, 19 December 2014 (UTC)

Is it true that any tendon has two sides - one connected to muscle and the other to the bone or cartilage?
Is it true that any tendon has two sides - one connected to muscle and the other to the bone or cartilage? another sentence that I think about is that always tendon needs to be connected to the muscle or the bone. not? 149.78.45.16 (talk) 02:58, 19 December 2014 (UTC)
 * Wikipedia has an article titled Tendon which may be able to help you learn more about tendons. -- Jayron 32 03:56, 19 December 2014 (UTC)
 * There may be special cases (Patellar tendon), but the answer to your initial question is generally 'yes', as is stated in the first sentence in the lede of the article that Jayron32 linked to. --NorwegianBluetalk 23:38, 19 December 2014 (UTC)

how many people with gonorhea eventually go on to develop prostatitis?
Or maybe a better question to ask is, how common is acute prostatitis, and of those with it, how many test positive for gonorrhea? — Preceding unsigned comment added by 199.119.235.174 (talk • contribs)

What's taking so long?Whereismylunch (talk) 4:20 pm, Today (UTC−5)


 * Assuming it is not developing prostatitis you are in a hurry for, you can google "gonorrhea percentage prostatitis". μηδείς (talk) 21:26, 19 December 2014 (UTC)

Hard to find an answer, compared to when I looked many weeks ago percentage of oropharyngeal cancer patients positive for hpv.Whereismylunch (talk) 22:27, 19 December 2014 (UTC)
 * According to UpToDate ,


 * The pathogens associated with acute prostatitis reflect the spectrum of organisms causing cystitis, urethritis, and deeper genital tract infections (such as epididymitis). Gram-negative infections, especially with Enterobacteriaceae (typically E. coli or Proteus species), are the most common. In retrospective studies of men with acute bacterial prostatitis, such pathogens have been identified in positive urine cultures at the following frequencies:
 * E. coli – 58 to 88 percent
 * Proteus species – 3 to 6 percent
 * Other Enterobacteriaceae (Klebsiella, Enterobacter, and Serratia species) – 3 to 11 percent
 * Pseudomonas aeruginosa – 3 to 7 percent
 * Sexually active men may have sexually transmitted urogenital infections, which also acutely involve the prostate, in which case Neisseria gonorrhoeae and Chlamydia trachomatis are important pathogens. --NorwegianBluetalk 23:29, 19 December 2014 (UTC)

At what frequency has gonorrhoeae been identified in positive urine cultures?Whereismylunch (talk) 01:19, 20 December 2014 (UTC)
 * I figured this was a troll when I saw he edited in a signature over the unsigned IP address, and he has been indeffed. μηδείς (talk) 03:35, 20 December 2014 (UTC)

HIV testing
I know about the window period for HIV testing, but (and I'm asking this question without much scientific knowledge so bear with my ignorance) is there a particular point at which testing will pick up HIV?

Am I right in thinking that HIV tests will test positive after seroconversion occurs? Is seroconversion the same as acute HIV infection (early HIV symptoms)? After the acute HIV infection, is the patient seroconverted and the HIV detectable?

What about during the acute HIV infection?36.224.250.37 (talk) 18:20, 19 December 2014 (UTC)


 * Seroconversion. μηδείς (talk) 21:17, 19 December 2014 (UTC)


 * "Seroconversion" occurs when the infected person produces antibodies against HIV antigens in sufficient amounts to be detected. Tests that detect the HIV virus itself will usually be positive a few days before seroconversion. There are tests that detect HIV proteins and tests that detect HIV nucleic acids. See Diagnosis of HIV/AIDS for details. According to that article, nucleic acid testing (NAT) appears to be preferred in the EU for blood donor screening (somewhat unclear in the article). I doubt that that is generally true, although it may be true in some EU countries (I know that it's true in Denmark). The EU blood directive does not mandate the use of NAT testing for HIV. In Norway (which is not technically part of the EU, but which through the EEA agreement is more faithful to EU regulations than most EU countries), combined tests (that detect both HIV proteins and antibodies against HIV) are used in blood donor screening. --NorwegianBluetalk 23:03, 19 December 2014 (UTC)


 * What is the nature of the relationship between seroconversion and the acute HIV infection? Does seroconversion occur while a patient is having primary HIV symptoms (if any)?36.226.148.49 (talk) 04:33, 20 December 2014 (UTC)


 * The HIV/AIDS article gives the symptoms of the initial acute phase of the infection. Have you understood the seroconversion article? μηδείς (talk) 05:58, 20 December 2014 (UTC)

Relative concentration of Chitinase in various fruits
Chitinase says:
 * Bananas, chestnuts, kiwis, avocados, papaya, and tomatoes, for example, all contain significant levels of chitinase.

Where can I find the relative concentration of Chitinase in these and other fruits? -- ToE 20:08, 19 December 2014 (UTC)


 * I don't know, but this pdf would be a decent ref for that sentence if you care to add it . SemanticMantis (talk) 20:35, 19 December 2014 (UTC)


 * If you are interested in chitinases as food allergens, this web search may be of interest. --NorwegianBluetalk 23:14, 19 December 2014 (UTC)

Thanks so far. The food-allergens.de page says: "almost 50% of these allergic [latex alergy] patients also show hypersensitivity to some plant foods, especially chestnut, banana, and avocado, but also to kiwi, papaya, tomato and others." I don't know if that is because the former three have a greater concentration than the latter, or because they have different forms of Chitinase, which I understand describes a group of enzymes.

The allergen.org site gives specific allergens, such as Mus a 2 from banana, a "Class 1 chitinase", and Ziz m 1 from Chinese-date, a "Class III chitinase", but it doesn't seem to give the typical concentrations in the food source and doesn't explain the difference between the chitinase classes. -- ToE 12:33, 20 December 2014 (UTC)