Wikipedia:Reference desk/Archives/Science/2016 March 8

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March 8

Can we read minds with science ?

Not precise thoughts, exactly, but just whether something makes them happy or sad, for example. The idea would be to show disturbing videos, say of the Holocaust, to refugees from the Middle East, and put some electrodes on their heads to detect if the video makes them happy or disturbs them. Those that are made happy or at least undisturbed by scenes of mass death would be denied admission and returned to their nation of origin. Is this technically possible ? (Note that I am explicitly NOT asking about the ethics of doing so.) StuRat (talk) 03:41, 8 March 2016 (UTC)

Passing over the basic stupidity & repugnance of the idea, Functional magnetic resonance imaging says "Some companies have developed commercial products such as lie detectors based on fMRI techniques, but the research is not believed to be ripe enough for widespread commercialization". Polygraph says "In 2001, a significant fraction of the scientific community considered polygraphy to be pseudoscience". So. Mainly no, then. --Tagishsimon (talk) 04:15, 8 March 2016 (UTC)

Your suggestion is reprehensible and technically impossible in equal measures. Fgf10 (talk) 07:58, 8 March 2016 (UTC)

Note that for purposes of security theater, a device can be completely bogus and still see wide use as a reassuring "security precaution". Terrorists frequently report being disturbed by civilian casualties caused by the non-terrorist bombs that non-terrorist organizations detonate at public events, so I'm not sure which end of your spectrum would actually contain more terrorists. Still, it's possible that a generalized psychometric approach that excludes anyone who is too smart, too dumb, too shy, too outgoing, too suggestible, too resistant etc. will deliver a subset of "near clones" who all think and act alike; provided most are not terrorists perhaps all will not be terrorists. But I don't know if there's any proof for that assertion and somewhat doubt it, since there is probably more 'entropy' in the middle values, more ways for a set of random personal factors to tot up to seemingly average characteristics. The question seems rather fundamental to concepts of psychopath in psychology, so maybe there's something along that line to be found.

Note however that what you're asking is about predicting minds with science. It is much easier to merely read minds with science. For example, the would be entrant can be shown the cover of the current Inspire magazine and his P300 measured, and you can exclude him if he recognizes it. This is, obviously, a test that only works once; better yet, some wag might spam the (H-1B, typically) employees of Microsoft with some kind of email campaign to make them be excluded by the test... then threaten Apple they'll do the same to theirs if they don't fork over a couple of million bucks, which kind of defeats the purpose of hiring H-1Bs in the first place. ;) Wnt (talk) 11:56, 8 March 2016 (UTC)

The answer to your question "Can we read minds with science ? Not precise thoughts, exactly, but just whether something makes them happy or sad, for example." is simply yes for we already have done this [1] with fMRI and machine learning. --Modocc (talk) 14:31, 8 March 2016 (UTC)

• This is a large topic, with many approaches of varying degrees of sophistication -- the history goes back at least to the Thematic Apperception Test developed in the 1930s. Looie496 (talk) 16:35, 8 March 2016 (UTC)

You can do a lot more than what you've wished for/explained with/using science/technology, but, I guess, something[s] are just hypothesis... -- Apostle (talk) 18:12, 8 March 2016 (UTC)

A 1993 newspaper article (and many journal articles) said that a psychologist named Emmanuel Donchin proved that we can read minds with brain waves, specifically the P300 evoked potential: [2]. Computers are way faster now than in 1993 when it comes to analyzing brain waves. See also Brain-reading, Brain–computer interface and Brain fingerprinting which mention Donchin's work.Edison (talk) 06:45, 9 March 2016 (UTC)

I worked on a demo for Intific that was showed at a big Google event where we used a special headset that can extract various brain waves and process them to deduce things about how you feel. We made a little demo game where you flew around (inside a brain!) shooting at things. The game itself was very simple - but while you were playing, we measured the degree of "mental focus" you were applying to the task - that "in the zone" feeling you sometimes get when playing a computer game. When we detected that you had that mental focus, we'd increase the score you were getting at each hit. The only way to win was to focus intently on the task at hand. Distracting the player would immediately crash their scores and they'd have to work to get back into the zone. So, we were definitely "reading your mind" - albeit in a very simplistic, superficial kind of a way. It's the second piece in this video (exactly one minute into it): [3] SteveBaker (talk) 02:46, 12 March 2016 (UTC)

conjoined twins are usually born with two hearts or one?

I read this article on BBC about the existence of two hearts in woman and I found the following sentence: "Aside from conjoined twins, no human is born with two hearts". But I can not conclude from it if it's usually or not. 93.126.95.68 (talk) 04:57, 8 March 2016 (UTC)

Our article Conjoined twins lists the various types of conjunction that occur, and the percentage each contributes to the total. The first (28% of cases) usually involves the heart, while the second (18.5%) always does. Rojomoke (talk) 06:26, 8 March 2016 (UTC)

Wi-Fi part 2

Can heavy rain and/or thunderstorms interfere with wi-fi (other than by causing physical damage to the network)? 2601:646:8E01:515D:D1E0:6CC9:A57C:4C96 (talk) 05:57, 8 March 2016 (UTC)

If your wi-fi transmits across an outdoor space then heavy rain will affect it by reducing the signal strength. Lightning can affect the internal electronics, as with any electronic equipment. Dbfirs 09:28, 8 March 2016 (UTC)

But can lightning interfere with the signal without actually damaging the router? 2601:646:8E01:515D:D1E0:6CC9:A57C:4C96 (talk) 11:19, 8 March 2016 (UTC)

My intuition would be "yes" because electromagnetic fields can change the bits on a bus and in memory, but perhaps someone else with more experience and expertise can cite some research on this? Distant lightning would not generate a sufficiently strong field to cause a problem, but could cause a spike on the electricity supply, and this, in turn, could affect the router. Dbfirs 12:30, 8 March 2016 (UTC)

Lightning creates a broad-band burst of EM radiation, part of it in the wifi band. This adds noise to the wifi signal, reducing the signal-to-noise ratio and degrading the signal for a few deciseconds. This could affect you if the signal is already weak. The short wavelength of wifi radiation is easily absorbed by water in the air, so the lightning has to be quite close to have any effect. PiusImpavidus (talk) 13:05, 8 March 2016 (UTC)

To some extent it also depends on what you mean by "interfere with the signal" and "damage". While I never had a wifi router, after renovations my childhood home in Malaysia had a fuse box which was quite sensitive to lightning. Possibly there were some design problems or maybe it was because it was connected to all 3 phases which is a bit of an unusual config. I think there was a good true earth connected ground so having MOVs at the meter likely would have helped. But anyway this would rarely cause any damage, it would just fuse sometimes a few times during lighting storms (which are quite common in KL).

When there was damage, I'm pretty sure it was from the phone line. (Phone line connections also lack a MOV or any sort of protection at the entrance in Malaysia unlike the US. Or at least that's what someone on usenet said was the case in the US time after time.) We did have a lightning arrestor but one time that failed to protect and so the dialup modem died. (The arrestor also died but that was fairly common. Stupid me forgot to connect to disconnect the arrestor and so for a time I thought the phone line was dead until after 3 sets of telephone line technicians one of them diagnosed it as the arrestor.) We then largely relied on just disconnecting the phone line until one time this wasn't done and a lighting strike took out not just the ADSL router but most of the computer. (Definitely the mobo, can't remember about the PSU or monitor. Not sure if the CPU was even properly tested.)

While we never actually had an AP in the house AFAIK obviously if we did and without a UPS by cutting off the power to the AP it would interfere with the wifi signal rather badly until the fuse was manually reset. And without damaging the AP or anything else. (Possibly there was some very minor damage to something but this went on for many years without any clear problems other than with the lightning/phone line issue.)

Nil Einne (talk) 16:37, 8 March 2016 (UTC)

We actually had a brief power outage last night, although my equipment didn't "notice" it, as it all is plugged into an online UPS. Operatively here, what was theorized above about lightning EMF interference was what occurred at the time. A nearby lightning strike dropped the power for about ten seconds, at the same time, my wireless signal lost lock and had to reconnect. Water also can absorb RF energy, rain is obviously water and the shorter the wavelength, the more impacted the radio signal would be. For commercial applications, where a loss of signal or significantly degraded signal may occur, various methods were utilized to mitigate against signal loss, ranging from signal compression, directional antenna, high gain receivers, etc. After all, at the physical layer of WIFI in the OSI model, it's just a radio.Wzrd1 (talk) 19:57, 9 March 2016 (UTC)

[un-indent] Thanks, all! Pius Impavidus had the answer I was looking for. 2601:646:8E01:515D:3C06:A9A7:4EC1:51F0 (talk) 11:51, 11 March 2016 (UTC)

source for the sentence that humans have 7 subdivisions in renal medulla

I've read on the article renal pyramid that "The renal medulla is made up of 7 to 18 of these conical subdivisions (usually 7 in humans)." I would like to ensure that by a professional source, do you have? (I tried to search on google books but maybe because I'm not native English speaker I couldn't find) 93.126.95.68 (talk) 06:17, 8 March 2016 (UTC)

Type in to google "The renal medulla is made up of 7 to 18 conical subdivisions" and see what you get. This one from The University of Ottawa says 8 to 18, but the difference is fairly insignificant. The sentence in the article seems to have come from the Cram101 study guides one of which is here Richerman (talk) 10:07, 8 March 2016 (UTC)

Here's a cute variation: a "desert gerbil" with a single renal pyramid so long that it extends down the ureter. The system is so efficient at recovering water that it doesn't need to drink. :) On the other hand this source says that the morphology doesn't have to be so extreme for water to be recovered. It might be worth trying to figure out what species have what morphology and how well they conserve water at some point... Wnt (talk) 11:36, 8 March 2016 (UTC)

To be honest, in the books Gray's anatomy and Moore anatomy, the kidney is with seven pyramids, eve though I didn't it's written in words but the pictures says it. 93.126.95.68 (talk) 14:56, 8 March 2016 (UTC)

That may be for ease of illustration, though. Though it's possible, it does seem strange that the most common value (the mode) would be at the extreme end of the range. It's particularly strange that most sources give the range as 8 to 18, if 7 is modal. - Nunh-huh 05:19, 10 March 2016 (UTC)

How much power do field lights use?

Specifically, I'm interested in finding out how much it costs to run field lights for a typical American high school stadium - something equivalent to what's in the picture at right. How much electricity do they consume and at an average American electricity price, how much would it cost to light a field per hour. I'm only looking for a ballpark (pardon the pun) figure within, say, an order of magnitude. Edgeweyes (talk) 13:34, 8 March 2016 (UTC)

Here is the cost analysis for installing and maintaining (including electricity costs) field lights at Wilde Field at Lisle High School in Lisle, Illinois. --Jayron32 14:17, 8 March 2016 (UTC)

Keep in mind that the values can swing a great deal depending on the type of lighting used. LEDs in particular are often promoted as having fairly short payback periods due to their reduced power consumption in comparison to halogen bulbs. The amount of illumination required (probably a function of the size of the field) would also be a key variable. Matt Deres (talk) 14:54, 8 March 2016 (UTC)

In my neighborhood, road lighting and other large outdoor lighting installations have switched to using LEDs as part of a Department of Energy project. Here's LED Lighting Facts - Outdoor Area Lighting, a brochure from Department of Energy's Office of Energy Efficiency and Renewable Energy.

All this is part of the CALiPER program, "to address a need for unbiased, trusted product performance information in the early years of [solid state lighting]." As SteveBaker and others have mentioned, it is hard to compare long-term economics of LEDs because the technology is so new; the data collection is still ongoing to see how LEDs compare to other technologies when used in large, bright, high-intensity outdoor settings over decades. The DoE websites I linked contain loads of quantitative data. Nimur (talk) 16:22, 8 March 2016 (UTC)

That short "payback period" would be for replacing incandescent bulbs. That won't apply at all for new installations, while for replacing CFL bulbs the payback period will be much longer, since LEDs cost more but are only slightly more efficient than CFLs. StuRat (talk) 15:15, 8 March 2016 (UTC)

Sure, in the home or office, LED lamps are substantially the most efficient, and the longest lasting, and not as harmful to the environment as CFL's. In the last couple of months, their prices have dropped to almost the same level as CFL's and incandescents (From Walmart, 60W-equivalent: $0.99 for incandescent, $1.47 for CFL and $2.17 for LED...HomeDepot has 60W-eqiv LED's at $3.55 for a pack of two - 40W-equiv candelabra bulbs are even cheaper). I recently moved to a new home - and I've more or less replaced every bulb in the house with LED's. CFL's should be obsoleted now - they were a great stop-gap measure while LED bulbs cost $30 or more - but now that LED's are affordable, they need to go away. The reasons for sticking with incandescents versus CFL (unnatural color, slow start, poor brightness in cold conditions, mercury in the environment) don't apply to LED. You can get LED lamps in four shades of white now! They turn on instantly, and they don't care about the temperature and they last for so long that the manufacturers can't get a sufficiently high failure rate to measure it. There is no longer any excuse to stick with incandescents.

But we're talking about lamps bright enough to light a football field from some towers at the corners, operating well in extremes of cold and hot weather. It's difficult and expensive to replace them. That requires extremely specialized lamps - and I'd be very surprised if CFL's are even considered in that kind of application, or that sufficiently bright LED clusters are yet available. Either way, knowledge of what works in the home and office yeilds zero information about the OP's question. SteveBaker (talk) 15:49, 8 March 2016 (UTC)

Indeed, a quick review of the Department of Energy's detailed reports for the Outdoor Flood lamp category show that SSL (LED) lamps are often more power efficient, but sometimes they are less power efficient, compared to a metal halide lamp. So, LEDs have a lot of promise as a better technology for this application, but it still requires a careful long-term look at the practical engineering and economic details! Nimur (talk) 16:29, 8 March 2016 (UTC)

I get my CFLs for 50 cents each. Many of those disadvantages have now been fixed, as CFLs come in a range of color temperatures and brightnesses, instant start is available, and some work in cold weather. I actually like slow start for some applications, like when turning on a lamp first thing in the morning, when I'd rather not have it flash a blinding light in my face immediately. As for mercury, that may still be an issue, but throwing out all your CFLs early certainly won't help to prevent mercury contamination. StuRat (talk) 16:04, 8 March 2016 (UTC)

Six NHL arenas light their playing surfaces with LED light clusters. The referenced vendor lists an outdoor arena product with a -40° C to +55° C temperature operating range. So the tech exists, and is affordable at the professional sport level, but I don't know how far it's filtering down. I suspect new construction is going to be pretty much exclusively LED from here out, though. — Lomn 16:30, 8 March 2016 (UTC)

At the SAP Center (the Shark Tank), they also have a fascinating technology in which a professional photographer can connect to the arena lighting. Synchronous to each photograph capture, the arena lights strobe up to an illuminant level something like (WP:OR) four times brighter, for a net gain of something like 2 f-stops. I can't find any official documentation, except this brief mention from the Ice Hockey Officials of Northern California website warning not to let the strobes distract or annoy participants.

As an avid physicist and strobe enthusiast, I would love to read more technical information about what type of light can repeatedly boost the illumination of an entire hockey arena by some 4x, on command, with a response time and synchronicity on the order of tens of milliseconds! That's some serious technology, the sort of spooky stuff that The Government straps to the bottom of a B-17 to help the war effort!

Nimur (talk) 16:47, 8 March 2016 (UTC)

Running field lights for a typical American high school stadium might very well have a net negative energy cost. It is quite likely that the power saved by a large number of people going to the game instead of staying home with the lights, TV, computer and/or appliances running is a lot larger than the energy used by the stadium lights. This, of course, assumes that what you care about is total energy use. If you only care about how much energy the school has to pay for those other savings don't matter. --Guy Macon (talk) 16:51, 8 March 2016 (UTC)

It isn't "quite likely", though it's an interesting argument and worthy of some calculation. I suspect the gasoline used to drive to the venue - and I presume USians will tend to drive - on its own will outweigh any savings from the telly & lights being turned off at home. --Tagishsimon (talk) 16:58, 8 March 2016 (UTC)

Let's do some back-of-the-envelope calculations.

Amon G. Carter Stadium has 30,500 seats. The ten largest high school football stadiums in Texas range from 16,500 to 23,000 seats.[4] Smaller stadiums would of course cost less to light but would also have lower savings from fewer people not being at home. It costs $100 per night to light Amon G. Carter Stadium.[5] If this unreliable source[6] is correct, an average house uses about $2.40 in electricity a day. Mine is about $60/month, so that number is in the ballpark. BTW, our Domestic energy consumption article badly need expanding. If we assume 16.5 cents per person per day energy saving, that's $5,000 saved. You can plug in different assumptions, but you won't overcome a 50:1 difference in costs.

Gasoline costs are harder to figure. According to Miles per gallon gasoline equivalent 33.7 kilowatts kilowatt hours per gallon is about right. I am guessing three persons per car (two parents and one child), so perhaps 10,000 cars in the parking lot of our imaginary 30,000 seat stadium. I am also guessing that it takes about a gallon to get to the local high school and back, and $2 per gallon gasoline. So that's $20,000 spent on gas. Maybe $40,000. Now comes the hard part. How many of those people would have driven somewhere else that is farther away with fewer people in the car if they weren't at the game? --Guy Macon (talk) 18:20, 8 March 2016 (UTC)

Most of them weren't driving somewhere else because the premise of the comparison is that they stayed home to watch the game on TV versus driving to the stadium. Having said that, I accept that a few might drive to a friend's place or to a bar to watch it over a few beers. Akld guy (talk) 23:06, 8 March 2016 (UTC)

In that scenario, the stadium lights are on either way, an according to my back-of-the-envelope calculation above the energy used to drive the cars would almost certainly far outweigh the energy used by running the TV, cooking the snacks, etc. I am glad you brought up cars, because I was originally only thinking electricity. --Guy Macon (talk) 07:16, 9 March 2016 (UTC)

How do you convert "gallon of gas" (a energy number, Joule) to "kilowatts?" ( a Joule/sec power number)? --DHeyward (talk) 00:29, 9 March 2016 (UTC)

By making a dumb typo. It is, of course, kilowatt-hours. --Guy Macon (talk) 07:16, 9 March 2016 (UTC)

Thanks, Jayron, that's exactly the kind of thing I was looking for, and matches the type of field lighting I'm interested in. The key phrase, "cost to operate the lights would be approximately $6/hour", answers my question nicely. Edgeweyes (talk) 16:56, 8 March 2016 (UTC)

A factor we should consider when considering low cost but inefficient lighting versus expensive but highly efficient lighting is the duty cycle, or hours used per week. In an office or manufacturing plant which is used perhaps 50 hours per week, a small increase in efficiency can justify a much higher installation cost. In a high school football stadium where the lights are used, say, 4 hours per week, a lower efficiency but cheaper lighting system might be more cost effective. How many years is the payback time for a higher purchase price system which uses less energy, in a given application? This is engineering economics. Edison (talk) 06:27, 9 March 2016 (UTC)

When running is there an Vasodilation or Vasoconstriction in the blood vessels?

I think that in case of hot climate there is vasodilation because the body wants to cold the blood by the blood vessels in the surface of the body and the it makes them wider and in the most of the cases a lot of them even can be visible. Am I right? 93.126.95.68 (talk) 15:00, 8 March 2016 (UTC)

I can only attest to my personal experience. When I exercise in the cold, such as shoveling snow, my limbs get quite cold, while my core overheats. There is apparently a reaction to limit blood flow to the limbs, in order to conserve heat, but this reaction, at least in my case, ignores the temperature of my core, and seems to be solely based on the outside temperature. To try to compensate, I wear warm gloves but take my coat off. StuRat (talk) 15:11, 8 March 2016 (UTC)

It's a mix. Blood vessels that feed into muscles dilate, but blood vessels that feed into the guts constrict. The blood flow to the skin is determined more by temperature regulation needs than by activity per se: when you are too hot the skin vessels dilate; when you are too cool they constrict. The blood flow to the hands and feet can also be reduced if they are losing too much heat, but if they cool to the point where there is danger of tissue damage the flow will increase. In short -- it's complicated. Looie496 (talk) 15:18, 8 March 2016 (UTC)

Yes, it is complicated. It will differ if you are out for a training run or being chased by a tiger. If you are out for a training run, you will thermoregulate to effect homeostasis and blood will be moved around your body according to those needs. If you are running from a tiger, thermoregulation is temporarily dispensed with. In a typical Fight-or-flight response, blood is directed to the major locomotor muscles and essential organs such as the heart and brain. After you have escaped the tiger, your body will return to thermoregulatory processes. DrChrissy ^(talk) 19:13, 8 March 2016 (UTC)

Yep, *really* complicated. Even when running in a hot climate, homeostasis must be maintained, both in blood supply to muscles and to the skin for cooling. If one fully vasodilates, one would go into shock, as happens in anaphylactic shock. Meanwhile, various parts of the body can be vasodilated or vasoconstricted while running just to maintain homeostatis, as was mentioned in two responses above. The body maintains homeostatis by using sympathetic and parasympathetic nervous systems in opposition to one another to maintain a greater degree of control with only one operating at a time.Wzrd1 (talk) 19:48, 9 March 2016 (UTC)

Oort cloud

I assume the Oort cloud is so far only theoretical, no one knows for sure whether it really exists. However, I read that Voyager 1 will enter the inner extent of the Oort cloud in 300 years. Does this mean that after that time, we will receive definite confirmation about whether the Oort cloud really exists? JIP | Talk 20:15, 8 March 2016 (UTC)

The article states that by 2025, Voyager 1 will have effectively shut down. So it appears that the only way we can receive information about the Oort cloud is to launch another such spacecraft. Is this true? JIP | Talk 20:20, 8 March 2016 (UTC)

As with many things particularly those relating to astronomy or physics, I'm pretty sure it depends what you mean by "information" but the answer is probably no. See [7] [8] or if you're interested in the nitty-gritty perhaps read [9] [10] as an example of how we can get information without actually flying a spacecraft into or near to the Oort cloud and receiving information back. Nil Einne (talk) 21:01, 8 March 2016 (UTC)

Which question are you replying to? Is it "No, we won't get information once Voyager 1 enters the Oort cloud" or "No, launching another spacecraft is not the only way we can ever possibly get information about the Oort cloud"? JIP | Talk 21:24, 8 March 2016 (UTC)

If that isn't obvious from the refs (none of which refer to Voyager 1) and my actual answer (which also only refers to how we can get info without sending a spacecraft and never refers to Voyager or receiving info from a spacecraft) then I guess my answer isn't helpful to you. Nil Einne (talk) 21:37, 8 March 2016 (UTC)

Sorry, I didn't read through all the information you provided. I guess that's it has to do with the same problem as with the asteroid belt, that contrary to popular image, the Oort cloud, if it exists, is way too sparse to just get near it and notice a bunch of comets flying around all over the place. JIP | Talk 21:53, 8 March 2016 (UTC)

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is." Rmhermen (talk) 01:24, 9 March 2016 (UTC)

There may be other ways to detect it. Perhaps it can be observed by emissions of infrared radiation or perhaps by eclipses of stars. Perhaps neutral molecules can make through the vacuum from a cloud object to the vicinity of the Earth. So far it is observed by the large objects that appear to come from it, so more detailed observations and missions to long period comets may reveal more. I suspect Earth based radar and lidar do not have the range to reach it. Graeme Bartlett (talk) 00:44, 9 March 2016 (UTC)

I would expect that we would have lots of ships, still communicating with Earth, in the Oort cloud within 300 years. Just look at how many ships we have flying around the inner solar system now, and how impossible that would have seemed 300 years ago. However, as JIP noted above, just being in the Oort cloud wouldn't make it all that apparent, any more than being in the ocean makes it obvious that there are coelacanths there. StuRat (talk) 01:01, 9 March 2016 (UTC)

It's not like the Oort cloud is some kind of unicorn dream. We have observed ~5000 long-period comets [11] bound to the sun. The Oort cloud is simply the name given to the parent population of those objects. Because many of the observed comets have recurrence times in the thousands, tens of thousands, or even hundreds of thousands of years, it follows that most long-period comets are far enough away from us right now that they have never been observed. Thus we extrapolate a population of billions of comets from an observed sample of thousands. The properties of that population are going to be sketchy. Is it really a uniform cloud in all directions? What is its inner and outer limit? How many objects are out there? Etc. However, the argument for a large population of comets at the edge of the solar system far beyond the known planets is already on pretty good empirical observational grounds. Dragons flight (talk) 08:22, 9 March 2016 (UTC)

It seems fitting that the otherwise-unrelated word "ort" suggests what the Oort cloud would be - the "bread crumbs" of the solar system. ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:54, 9 March 2016 (UTC)

Wikt:Ort means "leftovers", to me, which is even better, since they are the leftovers from the formation of the solar system, perhaps with some captures from outside the solar system (the neighbor's leftovers ?). StuRat (talk) 15:42, 9 March 2016 (UTC)

Bingo. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:36, 9 March 2016 (UTC)

Provenance of image

Greetings, another image along my theme: Does someone here know what File:Wanderlust.jpg is an image of? Jo-Jo Eumerus (talk, contributions) 21:28, 8 March 2016 (UTC)

Any or all of the following:

1) A family vacation photo stolen from the Internet, original here: [12]

2) Somewhere along the coast of Oregon (according to Grant Chambless photo album)

3) "I went to this location and took a photo. Therefore this picture is mine."

It should probably be deleted as likely copyright violation. --Amble (talk) 23:50, 8 March 2016 (UTC)

Now listed at Wikipedia:Possibly_unfree_files/2016_March_8. --Amble (talk) 00:00, 9 March 2016 (UTC)

Does the ovum is made of many cells?

I've read that the one of the part of the spheres of the ovum has follicular (corona) cells and I was shocked because I always thought that the ovum is a uni-cell. Now I'm confused and I'd like to get an explanation.93.126.95.68 (talk) 22:38, 8 March 2016 (UTC)

Just click on Ovum. You see the ovum is in the middle, with the corona radiata (and more generally the cumulus oophorus) around it. This is a common state of affairs - for example, flies have nurse cells to do this task. The reason is that the egg is a huge cell, and it's the sort of exception that proves the rule: to be this big, it needs other cells pumping their resources into it. Nonetheless, technically the ovum remains a single cell inside its membrane - though at least in Drosophila there are actually cytoplasmic connections, and a stickler might call it a syncytium that only happens to have the majority of cytoplasm around one nucleus. Wnt (talk) 23:43, 8 March 2016 (UTC)

Thank you for your comment. But I still don't understand what is this complex of the ovum with all the cells that belongs to it - is called. Is there a name for all this complex? because I made google and of course I clicked on the article but I always see that it's called ovum includes all these accompanying cells. 93.126.95.68 (talk) 01:15, 9 March 2016 (UTC)

It's called the ovum. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:35, 9 March 2016 (UTC)

The ovum is a single cell - the haploid female gamete. It is surrounded by a cluster of smaller cells both in the ovary and in the uterus after ovulation - the ensemble being the Cumulus oophorus and forms one more hazard for the poor little sperm to get through. 109.150.174.93 (talk) 09:24, 9 March 2016 (UTC)

Thanks, I took the liberty of wikilinking more words in you text. SemanticMantis (talk) 15:37, 9 March 2016 (UTC)