Wikipedia:Reference desk/Archives/Science/2010 January 2

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January 2

formation of amides by reacting amides with esters

Because anhydrides and acyl chlorides are awful to use ... I'm having trouble finding a water-soluble ester where the leaving group has a lower boiling point than the ester. But maybe if I use acetone as a solvent (will it dissolve deprotonated amino acids or amino acids with charge of -1?), it will change the boiling point dynamics? Thanks. John Riemann Soong (talk) 01:34, 2 January 2010 (UTC)

Wouldn't you form an amide by reacting an amine with an ester?

Ben (talk) 01:44, 2 January 2010 (UTC)

Quite true. I'm actually trying to be cheap-ass and using a cheaper protecting group, since Cbz, etc. are quite expensive. I'm conducting various coupling experiments with amino acids. (The main reason why I want to protect the amino group is that I'm carrying out an aldol reaction, and a free amine in that position, in addition to being a competing nucleophile will end up forming a troublesome enamine during enolisation.) Although urethane formation wouldn't be bad either, if I could react an amine with an carbamate ester (though I don't see that happing conveniently). John Riemann Soong (talk) 01:50, 2 January 2010 (UTC)

Water may not be a not a wise choice if you are doing acyl-exchange reactions. You should be able to figure out why. Why not use the ester as solvent? Even if the alcohol LG does not distill out (I assume that's why you are asking about "LG" bp, but as usual you are not clear and precise in your explanations), the huge concentration of that ester would push the equilibrium forwards? But anyway, the bp trends should be obvious to you: longer chain on the acyl side of an ester raises ester bp without affecting bp of alcohol part (the LG being displaced), shorter chain on the alcohol part lowers bp of the ster and alcohol LG, longer chain decreases water solubility. So you can now do your own research by looking up the bp of a bunch of possibilities and decide what is the best compromise among these competing issues. DMacks (talk) 17:13, 2 January 2010 (UTC)

Calculate time and direction of Moonrise

How can I calculate the time and (compass) direction of Moonrise from a specified place on the Earth? Bubba73 ^{(Who's attacking me now?)}, 01:58, 2 January 2010 (UTC)

This might be a good resource (found by searching with Google for the phrase moonrise times). Tonywalton ^Talk 02:01, 2 January 2010 (UTC)

Thanks, but that says to put your information into their software. I want to list Moonrises that occur at night in a range of compass directions. I don't think there is a practical way to do it with their software, which is why I want to calculate it. Bubba73 ^{(Who's attacking me now?)}, 02:08, 2 January 2010 (UTC)

Do you speak Perl? If so, CPAN has modules specifically designed for this sort of thing; you could even reverse engineer their algorithms and write your own software from them if you wanted. Tonywalton ^Talk 02:17, 2 January 2010 (UTC)

Do you mean you want to do the calculation backwards from the way you first described it? You have a place and compass direction and you want to find a time and date when moonrise will be in the direction from that place? --Tango (talk) 19:12, 2 January 2010 (UTC)

For a particular place, I want to find out what dates and times that the Moon rises from a range of compass directions (basically south of east). I ordered a book that should give me enough information to write a program to do it. Bubba73 ^{(Who's attacking me now?)}, 20:49, 2 January 2010 (UTC)

Yoursky has a night sky map shown when you insert your latitude/longitude and specify a time in the past, future or right now. You might have to experiment with the time, however, until the altitude of the moon is close to the horizon. The numbers used for azimuth are discussed on the website. ~AH1^(TCU) 03:00, 2 January 2010 (UTC)

I have Starry Night (planetarium software) but it would be impractical to do what I need to do that way. Bubba73 ^{(Who's attacking me now?)}, 04:10, 2 January 2010 (UTC)

What about Celestia? Although I haven't tried any moonrise calculations myself. ~AH1^(TCU) 18:35, 2 January 2010 (UTC)

Thanks, but I don't see anything like what I need in it. Bubba73 ^{(Who's attacking me now?)}, 01:42, 3 January 2010 (UTC)

The procedure to find the time of moonrise or moonset is outlined on page 487 of Seidelmann's Explanatory Supplement to the Astronomical Almanac (1992). You may be able to find this at a library. Also, Jean Meeus has written a number of books on astronomical calculations for amateurs which you might find at your library.

The process of finding the time will also lead to finding the Greenwich Hour Angle and declination of the moon at the time of interest. These can be put into formulas available in the Astronomical Almanac to find the altitude and azimuth. The final step would be to correct the true azimuth to a magnetic azimuth. --Jc3s5h (talk) 19:57, 2 January 2010 (UTC)

The book I ordered is by Jean Meeus. Our library would not have the book you mentioned. Thanks for the reply, I think I'm on the right track. Bubba73 ^{(Who's attacking me now?)}, 20:44, 2 January 2010 (UTC)

Whoops, I saw that author but I actually ordered Astronomy with your Personal Computer by Peter Duffett-Smith. Bubba73 ^{(Who's attacking me now?)}, 20:52, 2 January 2010 (UTC)

Insomnia

Hi. First of all, I'm not asking for medical advice, just the name of a possible scientific term. Please do not give medical advice. In the article, it discusses several patterns of insomnia, and some of them encompass trouble falling asleep, maintaining sleep, etc. However, what is it called if the person is unable to sleep for the entire night? I've heard a non-scientific term as "pulling an all-nighter", but this usually refers to doing it on purpose. I'm not looking for delayed sleep phase disorder. Thanks. ~AH1^(TCU) 02:56, 2 January 2010 (UTC)

As far as I know there is no special word for that -- I would probably just call it "total insomnia". Looie496 (talk) 16:52, 2 January 2010 (UTC)

Really bad insomnia? Some related info: someone may believe they've had no sleep even when they have; insomniacs often underestimate their total sleep time:[1], and insomnia in which someone wakes up at 2 or 3am and then can't sleep the rest of the night is often associated with depression:[2]. Fences&Windows 17:17, 2 January 2010 (UTC)

OK, but could the person's brain activity, if it is very high during the night, cause the person to be unable to enter into phases such as deep sleep and REM sleep, thus causing total or near-total (ie. less then 2 hours) insomnia? ~AH1^(TCU) 18:19, 2 January 2010 (UTC)

Restless leg syndrome and PTSD have a loss of REM sleep.[3][4][5] Fences&Windows 21:33, 2 January 2010 (UTC)

One of the common symptoms of major depressive disorder is that people find it very difficult to fall asleep and then once asleep go very quickly into REM, thus leading to a very severe deficit of non-REM sleep, which is the restorative kind. Looie496 (talk) 17:45, 3 January 2010 (UTC)

How do birds shelter themselves in winter?

The temperature is hovering near 0° F here and the birds are nowhere to be seen. This led me to wonder: How do they shelter themselves in winter? --Halcatalyst (talk) 05:12, 2 January 2010 (UTC)

They most likely flew south. ~ Amory (u • t • c) 05:32, 2 January 2010 (UTC)

Supposedly a truck carrying monk parakeets crashed in New England, and all the birds escaped. Now they survive by living in the big power transformers (heat energy lost by voltage change keeps them warm through the winter) and are something of a political issue.-Craig Pemberton 07:23, 2 January 2010 (UTC)

(ec) Some birds migrate, but many hang around. If you put food out they will soon appear. The smaller ones shelter in creepers like ivy, and in evergreen trees and hedgerows. Larger birds like crows will roost in woodland. Pigeons like to roost or and around buildings.--Shantavira|^{feed me} 07:28, 2 January 2010 (UTC)

One of the properties of a bird's plumage is its insulation. Ask any penguin who has sat through howling blizzards for a couple of days, not to mention the chicks. Most birds that do not migrate tend to find a sheltered spot, hole or crevice and plump up their feathers. They may do this singly, but some species have discovered the advantage of communal roosting in low temperatures to conserve heat. Have you ever wondered why that cheeky little robin looks fatter when there is snow on the ground - s/he's just keeping warm. Caesar's Daddy (talk) 16:38, 2 January 2010 (UTC)

Bernd Heinrich wrote an entire book on this subject that I highly recommend: The Winter World: The Ingenuity of Animal Survival published in 2003. I highly recommend any book written by Heinrich; he is an excellent scientist and and excellent writer.--Eriastrum (talk) 18:27, 2 January 2010 (UTC)

• Thank you. I put this book on my wish list at PaperBackSwap.com. --Halcatalyst (talk) 22:46, 2 January 2010 (UTC)

(edit conflict)Migratory birds such as Canada geese are supposed to fly south for the winter, but more recently this did not appear to be the case. There are just my own observations, but in mid-November in S. Ontario, I saw a small flock of around 20 geese flying north, then a few days later I saw geese resting in a pond. At this point, there were still dandelions and earthworms. By 28 November, I saw a double flock flying south in formation with approximately 130 members. However, the next day, I think I remember seeing around 100 geese staying put about 15 km to our south. The next day, I saw a mosquito in my house and a friend reported seeing a caterpiller. On 3 December, I saw two geese flying north, after a storm had brought us colder air. I may have seen another flock flying south after that, but on 11 December I saw a flock of roughly three dozen geese flying north-northeast. Another big storm had just passed, and temperatures were close to -10C and very windy. After that, there were still seagulls around the area, and birds chirping in shrubs (as I have seen a few winters prior). ~AH1^(TCU) 18:33, 2 January 2010 (UTC)

Yeah, I just had to walk around a flock of Canada geese (wading in several inches of snow!) in Denver a few days ago, and while driving in the Great Plains a few days before that, I noticed a flock of geese heading north. Nyttend (talk) 13:51, 4 January 2010 (UTC)

Reverse orgasm/sinking feeling?

What is happening in your brain when crushing realization hits you and you just feel these terrible punishing feelings wash over you like a reverse orgasm? Is there a term for it? It is not butterflies in the stomach, fight or flight, nor panic attack although it is probably related it is negative and resigning. Any ideas? -Craig Pemberton 07:37, 2 January 2010 (UTC)

Do you mean Acute stress reaction ? --Dr Dima (talk) 08:39, 2 January 2010 (UTC)

Sounds to me like what you describe is just fear, if you feel it in your belly, mostly. It can feel like many things, but I think it just means one's brain is stuck on a feeling of fear. It's very common. --Neptunerover (talk) 09:18, 2 January 2010 (UTC)

Melancholia, depression, downer, anti-climax? Mitch Ames (talk) 13:06, 2 January 2010 (UTC)

Guilt? Cognitive dissonance? --Mark PEA (talk) 14:12, 2 January 2010 (UTC)

Acute stress reaction is probably the best description of what happens in the brain -- at a psychological level, the word I would probably choose is despair. Looie496 (talk) 16:49, 2 January 2010 (UTC)

See the article Major depressive disorder. Cuddlyable3 (talk) 23:17, 2 January 2010 (UTC)

Despair. 78.146.54.230 (talk) 15:05, 3 January 2010 (UTC)

Transmissible cancer

Noticing the main page in the news section, there is a post regarding transmissible cancer, in particular that scientists have discovered how devil facial tumour disease transmits. Apparently it is caused by the transfer of Schwann cells. My question is why does this make a difference? If a liver cell or blood cell was transferred between two Tasmanian devils, it would be removed by the animal's immune system. So what makes Schwann cells so special in the fact that they are not removed by the immune system as foreign cells? Do they lack antigens on their surface? Do they somehow affect the recipients ability to recognise cancerous cells? Regards, --—Cyclonenim | Chat  11:02, 2 January 2010 (UTC)

It's been known for a while that DFTD was a transmitted cancer and that the cells are identical, cytogenetically abnormal, small neuroendocrine-like cancer cells. The significance of the current report is that they used high-tech molecular biology to catalog the gene expression profile and it most closely matches Schwann cells. So, the origin of the tumor cells in the index case was probably a Schwann cell, that then progressively became cancerous and somehow developed the ability to transmit between individuals. I don't think there's anything particularly special about Schwann cells in terms of their ability to escape the immune system. The devil facial tumour disease article says that "the infectious facial cancer may be able to spread because of increasingly low genetic diversity in devil immune genes (MHC class I and II).[13] The same genes are also found in the tumours, so the devil's immune system does not recognise the tumour cells as foreign.[14][15]". The larger significance of the new research is that there may be a way to target treatments to the cell of origin, but this is speculative. --- Medical geneticist (talk) 14:11, 2 January 2010 (UTC)

Aurora/solar wind as an Earth power source?

Is there any way the interaction between the Earths magnetic field and charged solar particles at the poles could be exploited and turned into free electrical power? Trevor Loughlin80.0.106.142 (talk) 13:54, 2 January 2010 (UTC)

I'm not quite sure if this Geomagnetic storm is what you are asking. I seem to remember some time ago I read an article about why this can not be used as energy source but, I can't find the article now and I didn't understand the reasoning anyway. 93.132.179.189 (talk) 14:31, 2 January 2010 (UTC)

If you have a wire in a place with a changing magnetic field (and the Earth's magnetic field will change when it is interacting with solar wind) then a current will be induced in that wire. That is generating electricity from the interaction, however I doubt it would generate enough to be worthwhile. A solar panel would probably be a more efficient (in terms of cost) way of getting electricity from the Sun. --Tango (talk) 14:34, 2 January 2010 (UTC)

I remember asking a question on the Reference Desk proposing a multitude of ideas for electricity generation, including lightning, aurorae, animals, etc. and the answer was no. There was a NASA article on it. However, I cannot find the question in the archives, but in the case of lightning I remember something about it being difficult to convert from direct current to alternating current. ~AH1^(TCU) 18:14, 2 January 2010 (UTC)

Indeed - there is a big difference between something being possible and it being practical. I'm sure you could get electricity from lightning if you wanted to, but it would be far more work than it is worth. --Tango (talk) 19:08, 2 January 2010 (UTC)

What the OP talks about is possible except for the word 'free'. It wouldn't be free. In fact it would be quite expensive.Dauto (talk) 19:59, 2 January 2010 (UTC)

Yes, but solar energy and wind energy also cost money to build infrastructure, but aquiring the energy is a free process. ~AH1^(TCU) 20:15, 2 January 2010 (UTC)

No, wind power and solar power are not free either. Solar power is still more expensive then fossil fuels and wind power has only become price competitive in the last couple of decades. Dauto (talk) 01:42, 3 January 2010 (UTC)

If the only cost you consider is the immediate monetary cost, then yes, that is correct. If you consider a broader meaning of cost then you get a vastly different result. --Tango (talk) 01:45, 3 January 2010 (UTC)

Meaning please. Dauto (talk) 02:28, 3 January 2010 (UTC)

In the grand sense, human economics cease to matter, and only geophysical and astrophysical costs are relevant. Therefore, to extract the maximum possible usable energy from our environs, we need to run right up to the edge of the Second Law of Thermodynamics, by tapping off energy from the hottest possible source and dumping it into the coldest possible source, with as close to zero frictional loss as possible, taking into account the engineering details. It seems that the hottest energy reservoir we know of is the enormous quantity of binding energy stored in subatomic particles - we presently harness that with nuclear fission. The "costs" incurred, if we are going to walk down the lane of ignoring 2010-economic and into the realm of "speculative future costs", become impossible to define - so I posit that we just want to maximize the total time integral of the temperature differential of our energy source over geologic timescales, so that we can eject the maximum quantity of momentum out of our solar system; after the sun collapses, nothing else will matter. At present, it seems that we do this best with fossil fuel (and thus-derived chemical products); I have great hopes for nuclear energy in the future. Solar energy is great, but we can't really extract a lot of energy from it with current technology, in the form of photoelectric or "weird" electromagnetic energy such as those trapped in the aurora-related electromagnetic processes. I know some guys who claim to have used Earth's ionosphere and magnetosphere to extract energy, but it takes literally tons of fossil fuel (to power the radio transmitters) to get even a couple of watts of amplified energy extracted from the Earth's magnetic field. Nimur (talk) 15:27, 3 January 2010 (UTC)

I didn't really mean the entropy cost - that's far too long term to be significant in current decision making. I meant things like the limited availability of fossil fuels, the costs associated with global warming, etc.. --Tango (talk) 16:11, 3 January 2010 (UTC)

Sure, but global warming only has a human economics "cost" if it makes it more difficult for human life on earth (rather, it only has a cost if somebody is willing to sell it to the market at large, and the market is wiling to pay for it). Yet, if global warming makes life easier, then it's actually a benefit, not a cost. Who can speculate whether climate change will make life easier or more difficult 50,000 years from now? We can make sloppy estimates about the next 50 or 100 years, but to call that "long term" planning seems deficient. That's why I think Dauto is asking for your "broader meaning of cost" - if you break away from the actual economic cost, you just end up with an ill-defined concept. Personally, I think we've got bigger problems than global climate change, and it is a disservice to the real and actual problems that face our planet that we continue to place speculative future environmental catastrophe against actual, present social catastrophes that are easily solvable. Providing running water, electricity, sanitation, and so forth - all of these dramatically improve the quality of life - and they also have an energy cost which is going to be met with fossil fuel. The continued assertion by over-privileged nations that environmental catastrophe looms and threatens our quality of life on this planet seems intentionally oblivious to the huge number of real problems that are solved every time a dirty coal power plant turns on in a developing nation. And while we continue to seek replacements for our fossil fuel consumption, in the form of alternative energy sources, we simultaneously fail to capitalize on the existing, feasible replacement that exists in the form of nuclear energy. In the meantime, our carbon output continues to increase, and our global population continues to need energy. I'm going out on a limb here, but I think the OP's question about off-the-wall alternative energy sources is a result of a mass media flooded with misinformation about the realities of our energy situation. The fact is, we have plenty of fossil fuel - in the form of coal and petroleum. We also have enormous capacity to replace our fossil fuel sources with current technology - primarily with nuclear power electric stations. But, the reason there is a purported energy crisis has to do with economics - nothing more - and that it is too expensive to replace fossil fuels with alternatives. Much of the debate regarding climate change, as Tango has alluded to, is that there may be unaccounted costs when fossil fuel is burned - but the existence of invisible costs associated with climate change is an opinion, not a fact. That is called an externality and it only exists in certain philosophies of economics. Another way of looking at the situation is that the market has determined the price it is willing to pay for energy, and the suppliers have produced the only viable fuel that is available at that price - all "costs" are accounted for in the market price. We can extract energy from lots of alternative energy sources - space plasmas, hamsters on electric-generator-wheels - but the current economic situation dictates that adding these to our energy supply is not worth their marginal cost. Nimur (talk) 15:06, 4 January 2010 (UTC)

Replacing a diode

Hello, I need some help identifying an electronic component so that I can replace it. I am pretty sure it is a diode as the PCB it is from has a diode symbol >| on and there is a D for the component number. It needs replacing as one of the 'legs' has broken off. I have taken a photo but sorry it's not better quality, it's so small that I can't get a good focus on it.

Image: http://img509.imageshack.us/img509/1923/imgp1436o.jpg

The component is 2 or 3 mm long (excluding the legs)and is in a clear casing with a smaller red casing inside that. There is a yellow ring on the outer case and a silver ring on the inner case. I don't know anything about diodes, apart from that they ensure current can only flow in one direction. Is the component at the following link suitable? It looks very similar but I'm not sure the size is the same. http://www.maplin.co.uk/Module.aspx?ModuleNo=46386

Thanks,

Gary —Preceding unsigned comment added by 78.33.180.73 (talk) 13:56, 2 January 2010 (UTC)

click to enlarge

Well, to definitely identify the diode, we'll need more information. Do you have any idea what the circuit does? What sort of device (radio, washing machine, car electronics?) did it come out of? Do you have a photo of the whole board, and/or the area the diode came from? On the other hand, it does look very much like a 1N4148 (which is the Maplin component you identified), and that's far and away the most common type of signal diode. The 1N4148 will probably work, but a more accurate identification will help. Tevildo (talk) 14:13, 2 January 2010 (UTC)

I agrees with Tevildo. Doesn't look like a power diode at all does it? Do they still make 1N914 signal diodes? equiv. to 1N4148 anyway I recall. This picture from Diode may help but is unfortunately not labelled with the diode types. Fourth from the bottom looks the closest. --220.101.28.25 (talk) 15:16, 2 January 2010 (UTC)

It is definitely a 1N4148. These components were often marked with their part number in colour code. The bands in the picture are yellow and grey, coding for 48. I bet my Christmas dinner that the colours on the piece we can't see are yellow and brown, coding for 41. The part is still obtainable but if you are having trouble I have used BAT49 small-signal Schottky diode in a similar role as a fast switching diode in recent designs and I am sure it will be just fine here. (TERMINOLOGY WARNING - any "recent design" that I had a hand in is going to be at least twenty five years old). PS, the page you linked to at Maplin is a 1N4148 as shown by the part number in the search bax at the bottom. SpinningSpark 16:09, 2 January 2010 (UTC)

I agree it looks like half a 4148 but replacement depends on what its doing in the circuit: If it is biasing (or compensating) a silicon BE junct, then it better be a silicon diode. Or if in any way the circuit depends upon the ~0.6v forward drop, it better be silicon. These diodes (1N914/1N4148) are still available/current.--79.67.75.108 (talk) 03:39, 3 January 2010 (UTC)

On a side topic, for taking close-up images, many digital cameras have a "macro mode" that extends the focusing range (see this random article). On my camera, the button and display indicator uses a flower icon. -- Tom N (tcncv) talk/contrib 17:46, 2 January 2010 (UTC)

Thanks for all your replies, I suspect the diode is a 1N4148 so I will order a few from Maplins unless anyone has any further advice. To answer your questions, it came off a control panel PCB from an electronic organ, I have a photo of the area of the board here: http://img64.imageshack.us/img64/6563/imgp1439.jpg - the buttons adjacent to the diode have stopped working and when I inspected it, I realised that one of the leads had broken off the diode (D303). There are several identical diodes on this board near to the broken one but they appear to be OK. It is almost certainly not a power diode as there is a transformer inside the organ that steps down the voltage, all the boards are the LV side of the transformer, although for some reason, they have wires earthing them to the metal chassis. Thanks again for any further advice! —Preceding unsigned comment added by 78.33.180.73 (talk) 10:33, 3 January 2010 (UTC)

Looking at your picture, that's a very common piece of design, the diodes are part of the keyboard scan decoding and almost any signal diode is going to work as a replacement, but as I said above, use a fast one to be on the safe side. The stuff about the forward volt drop above is a red herring. First of all you are not easily going to find anything other than silicon nowadays, and secondly the forward volt drop of germanium diodes, even if you can still find one, is 0.2-0.3 volts, ie lower than silicon, so will still be read as a logic 0. Anything else, like selenium rectifier, for instance, does not come in small signal packages. SpinningSpark 12:57, 3 January 2010 (UTC)

Music/sound

If you blow into a short tube, it makes a high-pitched sound, but if you blow into a longer tube, it makes a low-pitched sound. What physical property causes this? --75.39.194.94 (talk) 14:26, 2 January 2010 (UTC)

This sounds like it might be a homework question, so I was going to give you a link to an article that contains the answer rather than just give you the answer, but I can't find such an article... Therefore, I will give you the answer: Resonance. If this is homework, please do go and read that article before writing down the answer - I don't want to get in trouble with your teacher! --Tango (talk) 14:41, 2 January 2010 (UTC)

Also see harmonic. Dauto (talk) 15:42, 2 January 2010 (UTC)

While harmonics are interesting further reading on the topic, they don't affect this question. The pitch of the note is determined by the fundamental frequency, the harmonics affect the timbre. --Tango (talk) 16:01, 2 January 2010 (UTC)

A cavity can be made to vibrate in higher modes, as any woodwind musician will tell you, simply by blowing harder. This is shown quite clearly in the article Dauto linked with the string example. This is not just harmonics of a fundamental, it is a change of mode resulting in a different pitch (at a harmonic of the first mode). SpinningSpark 16:18, 2 January 2010 (UTC)

True, but I don't think varying the embouchure is really within the scope of the OP's question. I used to play the trumpet (albeit not for long) so I am familiar with the idea, but I think it best not to confuse people with far more information than they ask for. --Tango (talk) 16:31, 2 January 2010 (UTC)

I was not really talking about embouchure, I was referring, and I suspect Dauto was also, to the normal modes of vibration of a system. SpinningSpark 17:17, 2 January 2010 (UTC)

They are the same thing, are they not? You select different modes by varying the embouchure. --Tango (talk) 17:48, 2 January 2010 (UTC)

It may be too late, but check out this link. I believer there is some discussion on pitch and cylinder length, and open vs closed cylinders. -- Flyguy649 ^talk 04:33, 6 January 2010 (UTC)

Schizophrenia and the human ear

There seem to be many hypotheses for what causes schizophrenia. Could it be caused by some type of small critter burrowing in through an ear into the brain? I ask because 1) It would make auditory hallucinations a plausible symptom. 2) The only way most of us can get detritus out of our ears is with our fingers, but for our nose and mouth we have sneezing, spitting, or swallowing and digesting--yet we get plenty of illnesses through those channels. It seems there should be "more" than just "ear infections" to make us sick by way of the ear than we are aware of. Thanks, Richard L. Peterson,just realized I'm not logged in. 69.181.160.248 (talk) 15:55, 2 January 2010 (UTC)Rich (talk) 16:01, 2 January 2010 (UTC)

The auditory hallucinations associated with Schizophrenia are often described as "hearing voices". Something burrowing in your ear may make you hear things, but I can't see how it would make you hear voices - it would most likely just be noise. --Tango (talk) 16:07, 2 January 2010 (UTC)

If a "critter" burrowed into the brain, it would cause a massive brain infection that could easily kill the victim, but it wouldn't cause hearing voices. Looie496 (talk) 16:44, 2 January 2010 (UTC)

• I don't think there is good reason to be sure of your statement.-Richard Peterson69.181.160.248 (talk) 17:13, 2 January 2010 (UTC)

There may be a link to middle-ear infections, see Peter Mason et al. 2008: Middle-ear disease and schizophrenia: case–control study. British Journal of Psychiatry, 193: 192-196 (though note a reply to this study) and Mason and Winton, 1995: Ear disease and schizophrenia: a case-control study. Acta Psychiatrica Scandinavica, 91(4):217-221.

A review of the association of physical illnesses and schizophrenia has this to say: "Mason and Winton (103) found that the middle ear disease was significantly more common in people with schizophrenia than in other people with psychiatric illness. There is also a large body of early literature on vestibular response abnormalities as an explanation for schizophrenia [for review see Levy et al. (104)] and on the association between deafness and schizophrenia [for review see Cooper (105)]. The hypothesis was that predisposed individuals with hearing impairment may misperceive auditory stimuli and may therefore develop inappropriate associations. This assumption found support in a study of a large cohort of 50 000 male Swedish conscripts. In a link of medical examinations of these conscripts with a Swedish National Register of psychosis care, the proportion of schizophrenia among those with severe hearing loss was significantly higher by a factor of 1.8."[6] More detail in this book by the authors of the review.

In contrast, a recent overview of auditory hallucinations and schizophrenia concluded that "auditory hallucinations are internally generated speech perceptions that are localized in the left temporal lobe".[7] Fences&Windows 16:50, 2 January 2010 (UTC)

I'm not entirely sure why you think the ear would be a more common means of transmission of diseases. The ear canal is much more of a closed system than the mouth or nose—it doesn't feed into the blood stream or the lungs or any of the other major organs in a straightforward way. It also doesn't get involved in food, mouth-to-mouth communication, sex, etc. It is also not the most straightforward path inside, protected both by hairs, a tight passage, and the fact that humans find things in their ears rather intolerable. There is also ear wax as a means of trapping and secreting things.

Re: the schizophrenia studies... there are a LOT of studies that show schizophrenia correlates with a LOT of things. I'm not an expert but I've seen enough of these things to think that either "schizophrenia" is such a large umbrella that it is looking at a lot of different things, OR that it is a general condition of the brain that is brought by all manner of things. On the general question of, "could it be caused by critters," it has also been shown to correlate strongly with Toxoplasmosis. --Mr.98 (talk) 20:05, 2 January 2010 (UTC)

I didn't say that I think more infections come by way of the ear than the mouth, just that there might be some "critters" that go in that we we don't know about. If humans find things in their ears intolerable, we probably have that response for a good reason. Also, trying to get a thing out of our ears with our fingers may push it further inside. Also, why wouldn't a licelike "critter" enjoy the hairs in our ear passages? But thanks for your and everyone's helpful and thoughtful replies. Best wishes, Rich (talk) 22:46, 2 January 2010 (UTC)

The reason we don't like things in our ears is because our ears are important and the insides are breakable. I don't think it's about avoiding disease. I think we'd be pretty aware if lice tried to get into our ears. Keep in mind that getting into your brain through your ear is a non-trivial matter... you'd know if something was boring its way through! --Mr.98 (talk) 23:12, 2 January 2010 (UTC)

(out) Mr. Peterson, schizophrenia is associated with a lot of symptoms beyond just auditory hallucinations (or even just hallucinations, for that matter; in fact, some people, myself included, believe the negative symptoms are much more debilitating than hallucinations). Frankly, the idea that schizophrenia--a disease that affects, or is affected by, a large neural network over most of the cortex--could be caused by a bug in your ear, is quite farfetched. rʨanaɢ ^talk/_contribs 00:19, 5 January 2010 (UTC)

Follow up wildebeest question

I recall seeing on a wildlife programme wildebeest that had become infected with a parasite that that did just what the OP described, burrowed through the ear (and I think eventually into the brain). This caused the poor wildebeest that had been afflicted to insanely rotate like a dog's "tail-chasing" game. The direction of rotation, apparently, being determined by which ear is affected. Does anyone know the name of the species causing this? SpinningSpark 17:57, 2 January 2010 (UTC)

According to this site, it's caused by a botfly. Matt Deres (talk) 19:10, 2 January 2010 (UTC)

People with schizophrenia generally don't just stand around and rotate. rʨanaɢ ^talk/_contribs 00:20, 5 January 2010 (UTC)

Did someone suggest that they did? You do not appear to be answering a question. SpinningSpark 17:47, 6 January 2010 (UTC)

Shampoo "build up"

For many years, I've heard an advice that you should switch your shampoo regularly, because sticking with one supposedly will cause the ingredients of that particular shampoo to build up in your hair. I'm somewhat skeptical as switching shampoo will work only if different shampoos have no common ingredients. Is there any truth to the supposed shampoo build-up problem? --173.49.16.188 (talk) 17:41, 2 January 2010 (UTC)

Well I don't know having 2 equivalents of ingredient A is any worse than 1 equivalent of ingredient A and 1 equivalent of ingredient B. If you're truly worried about ingredients remaining from your shampoo (which except for moisturisers, is a weird thing to be worried about since shampoos are designed to be water-soluble) it's better to find a shampoo with the least harmful ingredients and stick with it. John Riemann Soong (talk) 18:18, 2 January 2010 (UTC)

Snopes says no—look down on the page a bit to the parts about vinegar. Old shampoos, a long time ago, maybe. But modern shampoos, no. I suspect it is psychological. You use the same shampoo for years—you get used to how it deals with your hair. Maybe you get bored with your hair. You switch—and wow, there is something different with your hair! It feels a little different, smells different, etc. But this isn't because the old shampoo "stopped working" or "built up"... it's because you just got used to it. Switch if you want to, but don't think that there's some necessary reason to do it. This kind of vague old-wives-tale chemistry is, in my experience, usually a sign of the rumor being total B.S. (like the pads that supposed remove "toxins" from your feet, without specifying what "toxins" are being removed—as if there was just a chemical called "toxins" in the world for you to avoid). --Mr.98 (talk) 20:13, 2 January 2010 (UTC)

This may have originated during the 1980s, when 2-in-1 shampoos were developed and spiral perms were the fashion. These shampoos were supposed to coat the hair with something which rendered the perming chemicals relatively ineffective, and so other shampoos were developed to remove this build-up from the hair before perming took place. This page gives some ideas of what happens: [8] There's also this Wikianswers page which confirms my point about perms: [9] --TammyMoet (talk) 12:50, 3 January 2010 (UTC)

I don't buy the old wives' tales. You can find a million people helpfully saying "put vinegar in your hair" on the internet, but nobody can cite a reliable source or study saying it actually works. It sets off my B.S. meter in a major way. --Mr.98 (talk) 17:30, 3 January 2010 (UTC)

OK, but that's why I quoted a "professional" virtual haircare site. It's quite possible that companies who make the shampoos that remove the built-up product fromhair have done research on it, but won't publish it because it's commercially sensitive. Does the lack of published research evidence mean the experience of consumers is all BS? And also research in such fields tends to be medical because that's where the funding is (such as preventing or curing hair loss). Because I was a consumer who experienced the problem with perms, I am aware of the situation the OP refers to and I am aware of the products developed to remove build-up. It's taught on hairdressing courses too. Accredited courses in the UK generally don't go in for teaching "old wives tales". I suppose I could be wrong there though! --TammyMoet (talk) 19:41, 3 January 2010 (UTC)

Non-Ejaculatory Semen Removal from Testicles

Since the semeniferous tubules are constantly producing sperm, how is excess semen removed from the testicle if a male does not ejaculate (including nocturnal emission)?

The only statements that I've been able to find say that it is "re-absorbed" by the body. But by what process; are there specialized cells that facilitate this? --※Cōdell 18:16, 2 January 2010 (UTC)

I don't know about sperm in particular, but in general dead cells are absorbed by phagocytes (from Greek for, roughly, "cell that eats"), a type of white blood cell. It is likely that old sperm apoptose (kill themselves in a controlled fashion) and are then absorbed by phagocytes. --Tango (talk) 18:59, 2 January 2010 (UTC)

I can't remember which source I saw this in, but I believe Tango is pretty much in the right ballpark. Sperm apoptose after a given period of time and are removed by phagocytosis; or if not reabsorbed, the remainder are excreted through urination. In short, they don't build up in volume beyond a certain point, and excess sperm are removed by the aforementioned process. As far as I know, this doesn't involve any particularly specialised cell other than the sperm itself and phagocytes. Regards, --—Cyclonenim | Chat  19:49, 2 January 2010 (UTC)

How is dead sperm removed by phagocytosis if semen doesn't contain white blood cells?--※Cōdell 20:14, 2 January 2010 (UTC)

Not sure, but macrophages are found in the semen of some infertile men:[10] Fences&Windows 21:02, 2 January 2010 (UTC)

"Unejaculated sperm are usually phagocytized by macrophages of the reticuloendothelial system or by the cells lining epididymal ducts. In some instances, they may also be passed down the epididymal duct and combined with nitrogenous wastes",[11] i.e. some are passed in urine. Fences&Windows 20:46, 2 January 2010 (UTC)

More on phagocytosis of sperm, its role and mechanism are disputed: [12][13][14] Fences&Windows 21:02, 2 January 2010 (UTC)

Thanks so far. There are indeed opposing viewpoints in Fences&Window's links:

There is no convincing evidence for significant absorption of spermatozoa, defective or otherwise, by spermiophagy or dissolution in the epididymis of normal animals.[15]

Ubiquitin is secreted by the epididymal epithelium and binds to the surface of defective sperm. Most of the ubiquitinated sperm are subsequently phagocytosed by the epididymal epithelial cells.[16]

--※Cōdell 22:42, 2 January 2010 (UTC)

Vasectomy#Side_effects might help. Note that sperm and semen are not the same thing. Mitch Ames (talk) 07:41, 3 January 2010 (UTC)

Tortoise species

What is the species of tortoise mentioned in this article? Is it Desert Tortoise or something else? The Hero of This Nation (talk) 20:12, 2 January 2010 (UTC)

The article refers to them as such, so I suppose so (though they do mention it in a very generic sounding way, so I agree it's unclear). It would seem to be the Mojave subspecies, which our article mentions as being threatened. Matt Deres (talk) 21:15, 2 January 2010 (UTC)