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December 16

Fertility of male cockatiels?

Asking this question on behalf of a friend. How likely is it that a male cockatiel, aged approximately 20 years will still be physically capable of impregnating a female 'tiel, aged 3 years? He (apparently) still seems to be showing interest in 'girls' but my buddy has doubts over his (the cockatiel's!) potency, being fairly old for his kind... --Kurt Shaped Box (talk) 00:24, 16 December 2007 (UTC)[reply]

Picking off a mole

Is this possible, and what are the side effetcs? Will it completely go away? —Preceding unsigned comment added by 75.23.79.10 (talk) 02:52, 16 December 2007 (UTC)[reply]

See Melanocytic_nevus#Mole_removal. Moles should only be removed by trained medical professionals, so please consult your dermatologist instead of opting for self-surgery. Further, whether it will come back, or whether it indicates a possible disease can only be determined by a medical professional. Wikipedia prohibits reference desk answerers from providing any prognosis or diagnosis, so we can't answer this question in any more detail. Someguy1221 (talk) 04:42, 16 December 2007 (UTC)[reply]

[edit] wanna pee . . . but can't . . . Part 2

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

You really should see a doctor. MrRedact (talk) 05:59, 16 December 2007 (UTC)[reply]

Quality of English in scientific publications

Most of the journal articles I read that come from non-native English speakers contain a few errors of various types. The one I'm reading right now is peppered with them (e.g. "hardly to understand" for not understandable (kind of ironic, I suppose)). Don't scientific journals have native-English editors to avoid publishing such mistakes? I think it reflects poorly on the journal. --Seans Potato Business 09:37, 16 December 2007 (UTC)[reply]

Most people fail to understand that buying at a grocer's or chit-chatting with a passer-by requires a much lower level of English than writing a scientific article or a literary work. Overconfidence in their own capabilities is probably the cause for those mistakes, so they let them go unrevised. I could have been labeled as "fluent" in English five years ago, and I'm still learning (a lot), mostly thanks to Wikipedia and its Reference Desk. --Taraborn (talk) 11:34, 16 December 2007 (UTC)[reply]

It's particularly interesting that it's scientific publications that do this. Science requires above all the ability to think clearly, which goes hand in hand with expressing oneself clearly both orally and in writing. Maybe the editors have a lower standard for writings about scientific work than they do for the work itself. If so, that's a really bad policy, imo. Science would be nothing if the people who do the work couldn't communicate whatever they do to their peers and the general public. But maybe I prejudge. Maybe it's not confined to scientific publications. I'd actually be very surprised if it were. There's a whole new field of work opening up - people are being paid good money to fix the language mistakes others make, mistakes that in former days would not even have been acceptable from a 5th grader, let alone a tertiary trained scientist. Not sure where this is leading, so I'll just trail off now ...... -- JackofOz (talk) 12:47, 16 December 2007 (UTC)[reply]

This varies a lot from journal to journal. Many journals copy edit manuscripts extensively before publication, others don't. You usually won't find errors like the one you cited in top-notch journals. You can do great science without being fluent in English, and I wouldn't consider your example as an indication that the author was not thinking clearly. Of course, it can be annoying, especially if the paper ends up "hardly to understand". --NorwegianBlue^talk 14:20, 16 December 2007 (UTC)[reply]

I worked at a historical journal for many years; the heavy-handed editor there would routinely re-write the (very long) articles of non-native speakers (and heck, even a few native speakers—he was heavy-handed!). I only offer that up as an anecdote that some journals have people willing to do that sort of thing, but it is a lot of work, and at times gets so extreme that it blurs the definition of who the "author" of the article is (in the case of the journal I worked at, I once saw the editor re-write every sentence in an article for a non-native speaker—is the original author really the sole author of it, at that point?). --24.147.86.187 (talk) 17:47, 16 December 2007 (UTC)[reply]

This is a sort of grammatical trap for native German speakers. In English the suffix "-ly" denotes the adverbial use of the word "hard", whilst "hard" without a suffix is the adjective.

There is NO SUCH DIFFERENCE in German between adjective "schwierig" and adverb "schwierig", thus speakers are seldom aware of the specific function (ie does it define a noun or does it modify a verb). Once they have got the idea, they (well, we actually, as German is my native language) tend do make the odd parsing mistake, thinking "hardly to understand" clearly belongs to the verb "understand", so it must be an adverb, so it must be "hardly" to be correct. Oops, hardly...

I guess it would be comparable to a non-native German speaker using an accusative instead of a dative in conjunction with a specific preposition or mixing up genders of nouns. Maybe it should also be added that scientists generally seem to be non-verbal thinkers, which explains why some of them are "hardly to understand" if all you can see are printed words. --Cookatoo.ergo.ZooM (talk) 18:06, 16 December 2007 (UTC)[reply]

In my experience, most scientific journals don't edit for grammar, etc. They simply don't have the budget to be doing that. An article may be kicked back to the authors ~2 times for revisions, but if the grammar doesn't really get fixed, then eventually the journal editor has to decide between rejecting good science because of bad grammar or publishing it anyway. Most journals will generally do the latter and overlook poor English when the science is good. However, I do suspect that papers which are scientifically borderline are more likely to be rejected if they have poor English. Dragons flight (talk) 19:33, 16 December 2007 (UTC)[reply]

As a side-note, there is a category of mixed-up English that non-native English speakers come up with, especially in the Far East Asian countries, where it seems that they specialize in this sort of thing, that is known as Engrish. Here's a URL for a web site that celebrates the humorous mangling of the English language in Asia: http://www.engrish.com/ (warning, if you read this site while at a public terminal, people will look at you funny when you start laughing out loud uncontrollably - also, make sure not to have anything in your mouth while reading it, as it may end up spattered all over your monitor) Saukkomies 16:24, 17 December 2007 (UTC)[reply]

axon diameter

why does a greater axon diameter denote a higher speed of nerve impulse conduction? isn't it mainly the axon membrane that;s involved? —Preceding unsigned comment added by 116.48.84.133 (talk) 09:42, 16 December 2007 (UTC)[reply]

I have no clue about axons and nerve impulse conduction - but wouldn't a larger diameter signify a larger surface area and hence more membrane? SteveBaker (talk) 12:09, 16 December 2007 (UTC)[reply]

Action potential#Speed of propagation. --JWSchmidt (talk) 14:28, 16 December 2007 (UTC)[reply]

I cannot answer your question, but I can point you to an article that goes into detail about nerve impulse conduction. See Action potential. --NorwegianBlue^talk 14:26, 16 December 2007 (UTC)[reply]

I didn't look at the other two sources, but it has a lot to do with the threshold of the closed ion channels directly in front of (the direction of conduction) the most recently opened ion channels and how fast that threshold can be reached. The depolarization of the membrane is dependent on the flood of Na ions into the axon entering through voltage gated Na ion channels. Interestingly, what triggers the opening of those Na channels is a depolarization of the cell membrane around the channel. Once the threshold is reached, then the channel opens creating a rapid fast depolarization. The speed of the AP depends on how fast one group of channels can set off the next group. Increased diameter means more channels, less curvature of the axon membrane, and a larger volume within the membrane. All of these factors reduces the time it takes to depolarize the membrane and thus the threshold that will open subsequent channels can be reached faster, and the AP ends up going faster. Make sense? Mrdeath5493 (talk) 22:39, 18 December 2007 (UTC)[reply]

vortex dynamics : decay and impulse

Hello I have asked this before and got no answer so will try to ask it better this time. Vortex's do not suffer diffraction and do not lose impulse as quickly as normal acoustic waves. The pressure that the normal waves produce decays at R4 or four times the pressure when the distance is halved. Vortex's lose impulse as they travel due to the wake that they produce and do to the fluid they entrain as they travel which makes them grow and the pressure becomes less focussed does anyone know the decay rate of a vortices, and how much more force they exert closer to the source? If energy and speed are needed and the answer depends on an equasion and is different for every vortex the how about one of 500 joules traveling at half the speed of sound?

Thank you again

Robin —Preceding unsigned comment added by 80.6.37.199 (talk) 12:25, 16 December 2007 (UTC)[reply]

Devonian Sandstone?

Hi, just a quick question. I couldn't find anything on Devonian Sandstone, not that I need anything very detailed, I'm just wondering how porous it is? If so, is it enough to be a factor in how much water a river discharges? Thanks in advance and for any responses. 82.12.214.93 (talk) 13:22, 16 December 2007 (UTC)[reply]

There are many different Devonian sandstones worldwide (the most famous being the Old Red Sandstone), and porosity would vary both as to specific types, and within particular formations. Porosity of the underlying rocks does affect river flows, some rivers actually gain volume from a high water table in the rocks over which they flow, others lose water to the rocks, which can lead to dry valleys forming. The good people at the Geology WikiProject are probably better able than me to give a more detailed answer. DuncanHill (talk) 14:26, 16 December 2007 (UTC)[reply]

The article Hydrogeology may also be of use to you. DuncanHill (talk) 14:34, 16 December 2007 (UTC)[reply]

As may groundwater and Hyporheic zone. DuncanHill (talk) 14:37, 16 December 2007 (UTC)[reply]

This Is Not A Homework Question.

I read,this question in a Physics Magazine called PHYSICS WEEKLY.I had to describe the Motion of a penny dropped from THE EMPIRE STATE BUILDING,now THE EMPIRE STATE BUILDING`s height is 381 meters. How long will the penny,take to fall. I also wish to know the acceleration,The time and The Final Velocity.Again,this is not a homework question I tried to figure this out over and over again but couldn`t.PLEASE HELP —Preceding unsigned comment added by 68.161.87.185 (talk) 19:08, 16 December 2007 (UTC)[reply]

See this page (or any of the other discussions you can find by searching for "terminal velocity penny Empire State). If it's not clear, you can ask here about the part that's puzzling. - Nunh-huh 19:25, 16 December 2007 (UTC)[reply]

You didn't say the magic words "Neglecting Air Resistance". If you wish to recant and utter those magic words then what you need is in Equations_of_motion#Classic_version. However, if you insist on knowing how long it would ACTUALLY take - then as the Mythbusters showed, the terminal velocity of a penny is rather low - so it'll actually take considerably longer than that. I forget what number they came up with - but it was pretty slow. SteveBaker (talk) 19:58, 16 December 2007 (UTC)[reply]

The calculations, with and without air resistance, are both on the page I cited. - Nunh-huh 20:06, 16 December 2007 (UTC)[reply]

The exact answer will also depend on what orientation the penny was when it was dropped. If it is dropped with its plane parallel to the line of fall, it will take slightly different time than in other cases. Though how long it will take is kind of difficult to calculate, because it will result in complex aerodynamics after it starts to fall. I am assuming that when it was being released off hands, the mechanism was not precise, in a sense inevitably resulting in some initial small fluctuations out of its plane, which will later intensify with the contact of air as the velocity increases. Even if, we make particular care in releasing it, the two sides of the coin which are not same, will be treated differently by the turbulent air wakes, not resulting in same forces, again creating wobbles and will contribute to change the normal time slightly. This also makes assumption that there is no horizontol wind flow. Otherwise the coin will be pushed off its vertical line of fall and the time will change. - DSachan (talk) 20:51, 16 December 2007 (UTC)[reply]

To be literal, air resistance and orientation will not be of any use. When I was at the Empire State Building, I connected by camera to a pole and shot pictures over the edge of all the ledges that humans are allowed to access. As can be seen from a side view, the building is a stair-stepped pyramid. No matter where you reach out and drop your penny, it is going to fall one floor and land on the roof of the next floor down. So, the "Empire State Building" can be removed and replaced with a fall of 12-15 feet. -- kainaw ™ 21:14, 16 December 2007 (UTC)[reply]

Well - I'm not sure I agree with that. When you throw the coin - you can throw it out horizontally - it'll travel horizontally as it's falling vertically. Given that there is a fairly small terminal velocity in the fall, the coin has a LOT of time to move outwards before it starts to encounter ledges. I doubt there is a problem with hitting the ledges in practice. However, if you literally drop the coin - then, yeah - it's gonna end up on a ledge. On the Mythbusters show, they actually talked with one of the staff at the building and she said that the winds around the building are very strong and can even blow upwards. Given that, and the high wind resistance of the coin - I think the coin could wind up a mile away - or could end up back in the observation area...or anywhere in between. SteveBaker (talk) 04:00, 17 December 2007 (UTC)[reply]

I should have also pointed out the large quantity of pennies sitting on the roof below the main observation deck. It took me a bit to recognize them as piles of pennies (and many various other things). When I did, I began to wonder about it. Not just one person - many people have tried to toss pennies off the Empire State Building. I'm sure they clean the roofs periodically, so this was many people trying recently. What were they thinking? "Hmm... I wonder if I'll kill someone by tossing a penny off here. Let me try." This is really no different than "Hmm... I wonder if firing a gun into a crowd of people might kill someone. Let me try." Anyway, the winds around the roof do blow upwards with a very strong current. If you attempt to throw a penny horizontally outwards, I expect the winds to blow it back and drop it on top of the piles of pennies already there. -- kainaw ™ 13:18, 17 December 2007 (UTC)[reply]

Wont the coin orient itself naturally to the position of least air resistance: ie wont it fall edge on if given enough time to stabilize? This seems like common sense, but am I wrong?--TreeSmiler (talk) 02:11, 17 December 2007 (UTC)[reply]

The Mythbusters experiment showed very clearly that the coin tumbles all over the place - it doesn't matter how you drop it. See also my previous response about the winds in the area. SteveBaker (talk) 04:00, 17 December 2007 (UTC)[reply]

Tasting through my fingers?!

The DMSO article has this to say about my sense of taste: It has a distinctive property of penetrating the skin very readily, allowing the handler to taste it. Its taste has been described as oyster- or garlic-like. - how am I supposed to taste something just from it penetrating my skin? Are traces supposed to make it to my taste buds? --Seans Potato Business 21:45, 16 December 2007 (UTC)[reply]

Just in case anyone was doubting, the exerpts alone from a Google Scholar search confirm this is actually true (which surprised me utterly). Someguy1221 (talk) 22:03, 16 December 2007 (UTC)[reply]

I was told that it absorbs into the blood stream through the skin so quickly that it ends up hitting your taste buds in sufficient quantities that you can taste it. I was told I could try it, but opted out. -- kainaw ™ 00:02, 17 December 2007 (UTC)[reply]

I have experienced this and it is unpleasant. A quick search indicates that it comes from the exhaled dimethyl sulfide metabolite. --Joelmills (talk) 00:32, 17 December 2007 (UTC)[reply]

I too have experienced this garlic-like taste of DMSO. I also had a rather unpleasant experience, which I swear is true. I was using DMSO on my finger joints to see whether it would help the pain I get in them sometimes when I have to work outdoors on cold days. I'd heard from a folk remedy expert (my wife) that it would help people with arthritis, so I rubbed some on myhands and went outside on an early Spring day to work in the garden. We were putting steer manure on the garden and working it into the soil, when suddenly I began to taste the steer manure in my mouth!! I had definitely NOT put my hands or anything else close enough to my mouth for something to get inside, and the manure was wet, so I couldn't have breathed in some of its dust. The explanation was that the DMSO on my hands had mixed with the manure as I was working it, and then transported this through the skin on my hands and into my bloodstream, eventually reaching my taste buds on my tongue. I was literally full of manure! It was, quite understandably, the last time I used that stuff! Saukkomies 17:02, 17 December 2007 (UTC)[reply]

Just an interesting side note, Wired Science ran a segment about one sensory organ doing a different job, such as in this article where the tongue helps people (who have lost their balance) balance. --71.117.37.108 (talk) 04:10, 3 January 2008 (UTC)[reply]

Negative Black Hole

Is it possible that black holes could be made up of compacted negative matter, in some and matter in others. The reason I ask this question is that if there could be in fact be different charged black holes, a theory of the origin of the Big Bang could be made. One could be made through the fact that two different charged black holes meeting and coliding would cause a very big explosion such as a Big Bang. ARedens (talk) 23:31, 16 December 2007 (UTC)[reply]

Does the current big bang theory allow for the existence of black holes floating around before its occurrence? --Seans Potato Business 23:38, 16 December 2007 (UTC)[reply]

One could be made through the fact that two different charged black holes meeting and coliding would cause a very big explosion such as a Big Bang

How can you call this wild speculation a "fact"? Also, define negative matter. — Kieff | Talk 23:54, 16 December 2007 (UTC)[reply]

We have a link - negative matter. DuncanHill (talk) 00:03, 17 December 2007 (UTC)[reply]

The Big Bang theory allows for just about anything before its occurrence - the BB is a singularity, so it is just about impossible to say anything about what the universe was like before it - or if there was a universe before it, or even if there was a "before" before it. Confusing Manifestation(Say hi!) 02:25, 17 December 2007 (UTC)[reply]

When two ordinary black holes meet - they can coalesce into one black hole without too much drama. This seems to happen all the time in our universe - so it's no big deal. So what you are saying is that somehow because one is made of "negative matter" (or perhaps because it's electrically charged? You don't seem very clear on this point.) that something major and different might happen? It could be perhaps that an 'antimatter' black hole would meet a normal matter hole (note: Antimatter and negative matter and negatively charged matter are all different things) - and the result (if they were 'star sized' or 'supermassive' black holes would be the production of an ungodly amount of energy. But that release is happening inside a region where light (and energy) cannot escape - so it's still not clear that anything very exciting would happen. I don't see why you'd imagine that would somehow create a new universe. The "Big Bang" is a poorly chosen name. It's not just some very big explosion. It's the creation of spacetime itself - and a very large explosion doesn't in any way match the conditions under which the big bang started. SteveBaker (talk) 14:15, 17 December 2007 (UTC)[reply]

Actually, the name "the Big Bang" was created by Fred Hoyle to mock Georges Lemaître's idea that the Universe came from a singularity and expanded into what we see today, as opposed to Hoyle's steady state model of the Universe. However, the name was catchy and it stuck. I guess it's better than "the cosmic egg" or some other such names.

Regarding the original question, there already is a kind of "negative black hole", called a white hole, but that's not quite what you were describing, and they only exist mathematically.

Still, even if it was colliding +/- black holes, all you've really done is push back the beginning of the Universe, so it doesn't answer any questions. Personally, I kind of like the "crashing branes" theory of the origin of the universe, but the fact is, though we may learn a lot about the early Universe and have some ideas about what happened, we may never truly know exactly how the Universe came to be. I'm not saying we should quit looking, nor am I saying we should look for some "mystical" explanation, far from it. I'm just saying it might not be an answerable question. -- Hi Ev 03:46, 19 December 2007 (UTC)[reply]

Hi. I'm not sure if this is related to your question, but I recently read in an article in an issue of the Astronomy magazine, that black holes are neither truely matter nor antimatter, therefore an antimatter star approaching a black hole would recieve a similar fate to a matter star approaching the black hole. Besides, black holes have almost infinite density where the black hole actually is, so almost all characteristics and laws of physics of matter of a black hole, excluding mass, gravity, rotation, electromagnetic charge, and self-attraction are eliminated. Black holes are probably too dense for even quarks to exsist. Thanks. ~A H 1^(TCU) 22:54, 22 December 2007 (UTC)[reply]