Wikipedia:Reference desk/Archives/Science/2008 November 26

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November 26

'Writing about Vampires' seeks Comprehensive list of Disease Involving Sunlight

I'm a writer who is currently writing somewhat about vampires but what I really need is a comprehensive list of diseases involving sunlight to help with my current research needs. Thanks in advance. —Preceding unsigned comment added by 70.238.136.205 (talk) 01:24, 26 November 2008 (UTC)

This isn't bad: make sure you click the link to see the table. - Nunh-huh 01:29, 26 November 2008 (UTC)

For some people, going into bright sunlight triggers sneezing. See Photic sneeze reflex. I'm pretty sure this is not classified as a "disease" but it might be of interest anyway. CBHA (talk) 04:05, 26 November 2008 (UTC)

A disease you might want to check out that I remember being characterized as particularly vampiric is porphyria, which messes with the enzyme pathway that makes hemoglobin. Photodermatitis is sometimes a symptom. --Shaggorama (talk) 16:14, 26 November 2008 (UTC)

Tuberculosis sufferers were once thought to be vampires. See Tuberculosis#Folklore. - Draeco (talk) 05:19, 27 November 2008 (UTC)

Seasonal Affective Disorder (SAD) sufferers experience depression and other mood changes in the winter. Seasonal Affective Disorder is believed to be related to the much lower levels of sunlight in winter. CBHA (talk) 05:58, 27 November 2008 (UTC)

Xeroderma pigmentosum is a classic example of such a disorder. – ClockworkSoul 08:03, 29 November 2008 (UTC)

Black holes

Hi, A thought just occured to me while i was brushing my teath; what would happen if a human being was situated next to a black hole and stretched out their arm so that only their arm fell beyond the black hole's event horizon. Would they lose their arm? or would the black hole suck them in completely? 79.75.254.37 (talk) 01:27, 26 November 2008 (UTC)

The black hole gravity will pull hard on the arm, so if it is big enough to pull more than a few millimeters, the arm will drag the rest of the human in as well. However the tidal force and gravity would be expected to be huge as well, so even in an orbit around the hole you can expect to be spagettified. Graeme Bartlett (talk) 01:39, 26 November 2008 (UTC)

Being within armsreach of a sizeable black hole's event horizon is not a really comfortable situation! Between the spaghettification and being cooked by the gamma rays being emitted by stuff entering the hole...then the severe time, space and mass dilation effects of moving so rapidly...the fate of your arm is really the very least of your problems! SteveBaker (talk) 01:45, 26 November 2008 (UTC)

I saw a documentary about it... DMacks (talk) 02:11, 26 November 2008 (UTC)

An event horizon is not a magical shell where you don't feel the black hole's gravity outside of it, but you do feel it inside of it; F = mg still applies. For a small black hole with a high gravity gradient, see Steve Baker's answer. For a large one, the event horizon will be very large (such as the size of Pluto's orbit), and you won't feel much when you stick your arm in, but even if you then had your arm amputated, your space ship will require nearly infinite energy to escape the hole's gravity. If you find yourself in this situation, it's probably best to just keep your arm on so that you can carry out your final activities intact. --Sean 15:35, 26 November 2008 (UTC)

What does "nearly infinite" mean? — DanielLC 16:01, 26 November 2008 (UTC)

If we assume that the black hole is large, and thus the tidal forces are small, and that there isn't enough other matter falling into the black hole in order to harm you, and that you are magically (or otherwise) hovering above the event horizon, then you would actually never experience your arm passing the event horizon because this event is at t = ∞ in your reference frame! That can be seen from the Schwarzschild metric. As your arm moves closer to the event horizon, the time dilation in your arm compared to the rest of your body will certainly cause strange effects.

Note that the situation is quite different for falling observers.

Icek (talk) 15:32, 26 November 2008 (UTC)

But the problem with that explanation is this 'magical hovering' bit - we simply can't let you get away with that - even in a thought-experiment. Once you stick your arm through the event horizon - you can't have it back because in order to escape the black hole, it would have to be moving faster than the speed of light relative to the black hole. You may not see anything different when you do that - but we know that light from your arm can't get back either - so if you didn't notice an abrupt change when you stuck it in there (which I agree, you don't) then it must be that there was only just BARELY any light coming from your arm BEFORE you stuck it into the event horizon. So there must be something very odd happening to you BEFORE you stick your arm across the event horizon in order for that not to be very noticable.

But remember - in the absence of 'magic' - in order to avoid the rest of your body getting stuck in the hole too - when you're just a foot or two outside the event horizon - you have to be moving at 99.9999999% of the speed of light relative to the black hole! The event horizon is just the place where you can't escape even by moving at the speed of light. In the region close to the event horizon, you can only avoid falling in if you're going 99.9999999% of the speed of light...sure, it's possible to escape falling in theory - but severely difficult in practice!

So we can deduce that you are orbiting the black hole just the slightest smidgeon below lightspeed (relative to the black hole itself). That is insanely fast! At those speeds (and - inevitably - in a circular or elliptical orbit) you only have to glimpse a particle of matter falling into the hole to be completely cooked by the resulting high energy gamma radiation. This really isn't a good way to run your life!

SteveBaker (talk) 20:02, 26 November 2008 (UTC)

Unfortunately, such a kind of orbit is not possible; at 1.5 Schwarzschild radii the orbital speed already reaches the speed of light, and no closer free-falling orbits are possible! (the time dilation factor for circular orbits in the Schwarzschild metric is ${\sqrt {1-{\frac {3\;r_{s}}{2\;r}}}}$) Icek (talk) 22:46, 26 November 2008 (UTC)

Are CD jewel cases recyclable?

I'm moving all my CDs to flip albums and I have sacks of discarded jewel cases. Just curious if CD jewel cases are recyclable? The clear plastic is obviously different from the gray Cd holder part. But I don't see any plastic classification symbols anywhere. --68.88.175.36 (talk) 03:21, 26 November 2008 (UTC)

These cases are probably polycarbonate, this is one of the plastics that are not recycled much. However there would be other people who would like to use the cases as they are to store CDs, so I think you will be able to give them away easily. Graeme Bartlett (talk) 10:17, 26 November 2008 (UTC)

Are you sure of that? I know the CDs and DVDs are polycarbonate but I'm not so sure about the jewel cases. From the examples given in the linked article and the properties, it seems a bit odd to me they would use something like polycarbonate for jewel cases which are meant to be cheap, not especially hardy and mostly disposable. I've comes across various people suggesting they are type 6 (polystyrene) or one person suggested type 5 (polypropylene) which seems more likely to me. Specifically this [1] which means one of the slim line cases having a type 6 code and says it's confirmed from a government website. This website about manufacturing them [2] also suggests they're polystyrene. The (usually black) insert may be different from the clear/jewel part though, not sure (however there are those with transparent/clear inserts which I presume are the same at least Nil Einne (talk) 13:01, 26 November 2008 (UTC)

The best idea as others have said is to give them to somebody that can reuse them - libraries are often after jewel cases as people borrow their discs and bring the cases back broken. However, they definitely can be recycled - at least here in the UK. The company I work for sends all its scrap CDs and any excess jewel cases (including the paper inlays and black plastic parts) to a company on merseyside who recycles the lot - see this website: http://www.polymerrecycling.co.uk/cd.html I think they take them for free as well although you would have to pay to ship them there.62.25.96.244 (talk) 13:24, 26 November 2008 (UTC)

Lights

If two identical spotlights shining on the floor overlap, the intensity of the overlapping region doubles. If light is a wave, whhy would this happen? Wouldn't the light interfere with itself? —Preceding unsigned comment added by 76.68.247.230 (talk) 04:12, 26 November 2008 (UTC)

Because spotlights aren't coherent light. Unless the two beams of light are of the same wavelength, they won't interfere with each other. Spotlights feature a wide spectrum of wavelengths, and these don't interfere any more than a room full of musical instruments all playing at the same time (i.e. an orchestra) would interfere... --Jayron32.talk.contribs 04:40, 26 November 2008 (UTC)

It's not just the variety of wavelengths. Even a pair of Sodium lamps (which basically emit only two frequencies) don't interfere. The real reason is that the light isn't 'coherent'. Imagine a good old fashioned tungsten filament lamp - or a florescent tube maybe...each little part of the filament or of the glowing surface is giving off a little bit of light...right down to the individual atoms - each one is emitting light. But nothing is keeping the lightwaves they produce in synchronism - so at any given instant, some of the tiny light emitters that make up one 'lamp' are at the crest of their waves while others are in the trough and others are at the halfway point. Nothing forces them to stay together. Even if they were 'together' at the start, the shape of the filament/tube is such that the sources of all of these lightwaves are starting out at different places and radiating outwards in all directions...so they might interfere constructively here - and destructively there. As Jayron says - in the case of a white lamp - the light is coming out at all different frequencies too - and that complicates matters still further.

So the light that comes out of such a crude device is a horrible mixture of interfering lightwaves...it's a complete mess. But on the average of quadrillions (at least) of individual glowing atoms - there is light. OK - now add a second lamp...now you're averaging over two quadrillions instead of one quadrillion...but the results are much the same...except that there is now twice as much light energy. But even a pair or completely monochromatic light sources don't form interference patterns unless the light is 'coherent'.

To get some nice interference going, you need something like a laser - which (by devious means) produces 'coherent' light - where all the waves are in perfect synchronism and all at one very specific frequency. Laser light does indeed interfere in situations like your thought experiment - and if you could hold the lasers still enough and peer at the ground with a microscope - you'd see tiny interference patterns.

SteveBaker (talk) 19:46, 26 November 2008 (UTC)

Fuel consumption with a cold engine.

My car (a turbo-charged MINI Cooper) manages about 40mpg (US gallons) when I drive it carefully. I'm aware that car engines use more gas when they are cold - but today I found out how much more...and I'm astounded!

The car has a miles-per-gallon gizmo - but it's basically useless because it either averages over the entire life of the car - or it swings wildly moment by moment and tells you nothing useful. So I've always known my average MPG - but didn't get a good feel for how it varied over a journey.

Well, this morning, I was kinda low on gas - so I switched the car computer over to tell me "available range" (really: "miles remaining until you're out of gas"). It's not a mode I use much...but it turns out to give you a much better idea of what's going on. It's a 17 mile trip to work - and when I left home, it said I had 77 miles worth of gas in the tank. After just about 8 miles, I glanced at the gauge and noticed to my horror that it had dropped to 55 miles(!)...22miles off of my 'available range' but only 8 miles travelled!!

By the time I got to work (about 9 miles further) the gauge showed 50 miles left - so the first 8 miles of my trip used four and a half times more gas than the second half! Almost the entire trip is on freeways and I leave early enough to miss all the traffic.

Having an enquiring mind - instead of filling up the tank - I repeated the experiment on my drive home - and got very similar results. But it was astounding how fast the 'available range' dropped in the first mile alone. This was a good test because I was doing the trip in the reverse direction so the first half of the first trip was the second half of the second trip.

Tomorrow I'm going to make a note every mile...graphs need to be plotted! The world needs to know!

So here is the question...what the heck makes a cold engine use FOUR TIMES as much gas as a warm one?!? I can think of a few small things (like the engine oil isn't as runny) but that doesn't seem enough to account for the difference!

SteveBaker (talk) 05:37, 26 November 2008 (UTC)

Perhaps your gizmo got some glitches. I think you need an alternative way of measuring your fuel consumption (If you have the time to find one, sorry I have no idea what would that be) to compare with the data your gizmo provides.--Lenticel ^(talk) 05:50, 26 November 2008 (UTC)

If your car is new enough, you can get an aftermarket MPG display. I've been thinking about getting one, just for kicks. But the ones I've seen are a bit pricey. Doesn't answer the original question though. APL (talk) 14:12, 26 November 2008 (UTC)

The cheapest solution might be to write it up as a nice idea for Mythbusters -- they've done the small-quantity fuel efficiency sort of thing a few times before, as I recall (maybe suggesting that cold weather has an abnormally large effect can even call those previous experiments into question, too!) — Lomn 14:26, 26 November 2008 (UTC)

About the only way the engine could actually be burning that much more fuel is if the cylinders are missing (a lot). If that was the case the vehicle would be running very roughly and stalling. So, it must be the inaccuracy of the device. I'd compare this to the "time remaining" bar during a download. At the beginning, it tends to be highly inaccurate, but it gets more accurate the longer the download runs, as it's able to average info over a longer period to more accurately figure the current download rate. StuRat (talk) 14:53, 26 November 2008 (UTC)

Without knowing the details of how your car's "miles remaining" calculation works it's impossible for me to be certain, but I can think of at least a couple of confounding factors here which might explain your readings. When you turn your car on, it may be using the average fuel efficiency for your previous trip to calculate its "miles remaining". (Alternatively, it may use a factory-set 'default' value.) Once the car starts moving, the efficiency measurement is reset, and new calcuations are based on the current trip's data. Early in your trip, you will accumulate a lot of low-efficiency time: starting the car, stopping and starting at intersections, hard acceleration to get on the freeway and merge. By the time you reach the end of your journey, most of your time and miles are under efficient constant-speed conditions. Even counting the little bit of city driving at the end, the overall average efficiency for the mostly-highway trip will be good. You will see a similar effect on your journey home.

This is not to say that most automobile engines aren't appreciably less efficient when cold. Particularly in winter conditions, engine oil is quite a bit more viscous than it is at normal operating temperatures, and the engine has to work hard against that sticky, sludgy goo. But it generally takes very little time for a car to warm up when it is being driven. TenOfAllTrades(talk) 16:01, 26 November 2008 (UTC)

Answers above question the accuracy of the "miles remaining" information. Comparing that gauge information to when you have to fill the tank should give you a very good sense of how reliable the information is, IMO.

When I used to keep careful records of gas mileage, I was surprised at the dramatic difference between summer and winter gas consumption. It seemed too drastic to make sense - after all, so I thought, once the car has warmed up in the first part of a trip summer versus winter should not make a "lot" of difference. Parhaps my mistake was in underestimating just how much fuel was used in the warmup period. Unfortunately I did not have a "miles remaining" feature. CBHA (talk) 19:15, 26 November 2008 (UTC)

I think the way to discover whether there is something odd about the gauge (which is certainly possible) would be to drive the car from cold - then stop, turn off the engine, wait a minute - then jump back in and drive the exact same route again - but with the engine hot at the outset. If I'm right and it really is a cold versus hot engine situation - then the second time around would show normal consumption rates throughout the trip. I'll give it a try over the weekend.

But I do know that cold engines use more gas - that's a fact for sure - but what surprises me is the magnitude of that effect.

SteveBaker (talk) 19:30, 26 November 2008 (UTC)

Are you factoring in the gas used by starting the engine? --Carnildo (talk) 22:59, 26 November 2008 (UTC)

I didn't look at the 'miles to go' gauge until after I'd started the engine (because that's when it tells you you're low on gas) - so the cost of starting the engine was not a factor. SteveBaker (talk) 14:51, 29 November 2008 (UTC)

Though there are a number of salient difference, a internal combustion engine is still basically a heat engine so an appeal to the Carnot efficiency can be illustrative (if not entirely accurate).

Carnot: $E=1-{T_{Low} \over T_{High}}$

In this case, T_Low is roughly the temperature of the air-fuel mixture prior to ignition, and T_High is the temperatures of the vented exhaust after it has finished all delivering all the useful work it can. For T_Low lets take something around room temperature, say 300 K (27 C). I don't know, T_High, i.e. the gas temperature, but I do know one doesn't want the engine block as a whole to go much above 100 C (373 K), so maybe the gas exits at around 400 K (127 C)? That would give a thermodynamic efficiency of 25%. Now suppose we lowered these values to simulate starting on a cold day. If you take -13 C (260 K) and 50 C (327 K), that gives a thermodynamic efficiency of 20%, or in practical terms it might take about 1.25 times as much fuel to deliver the same amount of useful work. Of course cold also adds other variables like more viscosity engine oil, but ultimately, I think this is the right order of magnitude. I would guess an engine that is warming up probably uses 15-50% more fuel than a warm engine and not the 300% more fuel that your experiment suggested. Dragons flight (talk) 23:29, 26 November 2008 (UTC)

(The reason you don't want the engine block going over 100C is that it's water cooled. If the water gets even close to 100C, tiny steam bubbles form in the hotter regions of the engine block (close to the cylinders, presumably). Those bubbles are excellent insulators - so they greatly inhibit further heat from being transferred from that spot on the block to the water - that local hot-spot distorts the metal and is the major cause of a cracked block...which is generally totally terminal for your engine! So the 100C operating limit (it's generally more like 85C) is not an efficiency thing - it's a not-destroying-your-engine thing! SteveBaker (talk) 14:51, 29 November 2008 (UTC)

Yes, I know the limit exists because the engine is water cooled, but it is still an efficiency thing. IF the components of your engine were capable of running hotter, then the fuel would be used more efficiently. Dragons flight (talk) 22:46, 29 November 2008 (UTC)

I guess this is OR (if educated guessing is research) but the computer knows to a high degree of precision (a fraction of a spritz) your fuel consumption but is not so good on your remaining fuel volume. And the fuel management box could be fast-warming your engine/exhaust system. In the old days that was done by leaning the mixture. That would lead to inefficiencies, too.

An alternative testing method is switch to instantaneous-fuel-use mode and get to max BMEP (~3000 rpm. Best fuel economy, fast enough for drag effects to show but still a safe, cold-engine speed) for long enough for the mpg reading to stabilize (very steady on the throttle). Do this at the beginning and end of your trip. Compare and discuss :-) Saintrain (talk) 01:48, 28 November 2008 (UTC)

Modern fuel-injected engines deliberately run "rich" for the first few minutes in order to "light off"/"light up" the catalytic converter. That is, by running rich, unburned fuel makes it as far as the catalytic converter and burns there, rapidly warming up the catalyst to proper operating temperature. You, of course, see this as really poor fuel economy for a few miles.

Atlant (talk) 23:53, 30 November 2008 (UTC)

Endorphins and interest in sports

Does lack of interest in a sport lead to a failure of the body to produce endorphins while playing when they would normally be expected? Vice-versa? (As a child, I noticed that I was not only the least interested in sports of anyone in any of my gym classes, but also the least able to cope with pain from an injury.) NeonMerlin 07:54, 26 November 2008 (UTC)

An interesting theory. As for myself, I might be interested in playing a sport, but find watching strangers play sports to be as dull as watching paint dry; I simply can't make myself care who gets which ball into which basket/hole/crevice. StuRat (talk) 14:45, 26 November 2008 (UTC)

I saw a good discovery channel show on a phenomenon that equated competitive desire within sport to testosterone levels (in both men and women). It discussed a correlation between testosterone and overall desire to "compete" (in any area). Other than a means of keeping the body fit, sport is primarily an outlet for these competitive desires, especially in a decidedly VERY uncompetitive youth that most western societies establish. In a sport like American (or in my case, Canadian) football, some degree of injury (usually just soft tissue; the type of thing that won't be life-long) tends to occur in every outing, for example. From experience, I could always tell who would be most successful as being those that were most willing to "play through" those non-life-long injuries (not display any of the behavioural indications that an injury has been sustained, like holding an injured area or limping), not because of peer pressure or social expectation or rational reward, but rather just because of that internal competitive desire.NByz (talk) 20:50, 26 November 2008 (UTC)

It's been shown that athletes have higher basal endorphin levels and response (Inder et al, "Elevated basal adrenocorticotropin and evidence for increased central opioid tone in highly trained male athletes." The Journal Of Clinical Endocrinology And Metabolism [J Clin Endocrinol Metab] 1995 Jan; Vol. 80 (1), pp. 244-8.), so lack of playing could definitely decrease your central opioid tone. If you're asking whether a "naturally" decreased endorphin tone causes decreased sports interest, that's tough. I don't know of any studies that approach the question in that way, most likely because you would have to study children from early in development all the way to adulthood...a very ambitious undertaking. - Draeco (talk) 23:22, 26 November 2008 (UTC)

Boundries of longitude and latitude for western europe 1955-1990

I wanted to know what the boundries for Western Europe would be as far as latitude and longitude? I am needing these to know what a person would meet criteria for a US Military medal criteria. Many medals have a boundry criteria for an award of a medal in a theater of operations. Like the European-African-Middle Eastern campaign Medal, they have a boundry. I need to know the exact latitude and longitude of Western Europe from the above time periods —Preceding unsigned comment added by 70.212.140.156 (talk) 08:09, 26 November 2008 (UTC)

It probably depends a LOT on who is doing the defining. I would say that before 1989 or so, the eastern boundary of Western Europe was the eastern boundary of West Germany; eastern and southern boundaries of Austria, and eastern boundary of Italy. The question is whether to include such countries as the Scandanavian countries (politically yes; geograpically probably considered "Northern Europe"). Our article on Western Europe includes a half-dozen or so maps that define it in slightly different ways. --Jayron32.talk.contribs 11:38, 26 November 2008 (UTC)

4d rotation of 3d objects

Last year I've read the novella 'Flatland' by Abbott. Then I came along another website telling stories in a way similar to Flatland, e.g. 3d beings messing with 2d ones and 4d beings with 3d ones. In one section, a 3d human lifts a 2d book out of the plane where 2d beings live, flips it over (rotates it 180 degrees in 3d space) and puts it back. The book is reversed/mirrored. 2d beings are confused as no rotation in a 2d plane can make this happen. Similarly, the 4d being does the same to a 3d book and upon inspection we find that the book was mirrored. Unfortunately I can't recall that website but I hope you get the idea.

Well, after that I read in a short story (by Asimov, if I remember correctly) that such a rotation would mirror the molecules and if a man were to undergo that procedure, his amino acids would turn from L to D and sugar molecules D to L and in the end he may be starved.

Yet in another message board(!) I read that such a rotation would not only mirror the molecules but also turn every particle into its antiparticle thus upon returning to the 3d world the object would be annihilated into gamma rays.

Sorry for the lenghty intro but visualising these is really hard for me. So,

1- Does such a rotation mirror the molecules forming the rotated object?

2- Does it also turn the particles into antiparticles?

3- Could a 4d being watching us from "above" interact with our 3d universe to accomplish such tricks?

4- Are the questions already moot as the electromagnetic interactions essential for seeing, touching and rotating matter are confined to our 3d universe so there is no way a 4d being could watch us or interact with our objects?

5- Also invalid as such feats would violate conservation of energy?

5- Or not moot at all because there may be 4d photons, other 4d force carriers, etc for the 4d being to observe and interact with our universe? 3d beings may or may not observe those forces directly but they would observe the effects and not finding a cause, maybe they'd call it "dark energy"? .. Ok that one was pure speculation, but I couldn't help writing!

Thank you!! 78.176.16.183 (talk) 12:10, 26 November 2008 (UTC)—Preceding unsigned comment added by 78.176.16.183 (talk) 12:08, 26 November 2008 (UTC)

I think the answers to 1 and 2 would be yes. For 3 the answer would also be yes, but it could also be done in three dimensions with a non-orientable wormhole. Jkasd 13:42, 26 November 2008 (UTC)

The answer for (1) is yes, for (2) it's no (see Parity (physics)), the other points are moot because we don't know 4d beings or the hypothetical space they inhabit. The conservation of energy shouldn't be violated by mere mirroring. Icek (talk) 15:05, 26 November 2008 (UTC)

Addendum: You might also be interested in reading C-symmetry, T-symmetry and CPT symmetry. Icek (talk) 15:07, 26 November 2008 (UTC)

Just as a footnote - Abbots flatland really sucks - and I think I know the other book you're talking about...and it sucks too. Go out and grab a copy of "The Planiverse"...it's a MUCH better description of a 2D world. I absolutely guarantee it'll bend your mind! You can easily spend a half hour looking at each of the many illustrations - trying to figure out how (for example) the 2D steam engine works - or why the 2D house is built the way it is. Abbot's book is just awful by comparison. SteveBaker (talk) 18:42, 26 November 2008 (UTC)

Flatland's not bad, it's just not much good as a description of a 2d world. As a satire of Victorian society (the main point), it's ok. Algebraist 19:04, 26 November 2008 (UTC)

Um...it's kinda sexist...actually, outrageously, PAINFULLY sexist. It's embarrasing to read...you just want to grab the author by the throat and tighten your grip until he goes limp and finally quits this talk! His view of the 2D world is wrong in many regards (think about his descriptions of houses with doors and windows)...he kinda flips back and forth between a top-down 2D world and a side-on 2D world without proper consideration of what this actually MEANS. I dislike it greatly. Get a copy of Planiverse and you'll immediately see what I mean. SteveBaker (talk) 19:23, 26 November 2008 (UTC)

I haven't read the book for a while, but my recollection is that while the narrator (being a victorian gentleman) is outrageously sexist, the book itself is not. Algebraist 19:25, 26 November 2008 (UTC)

The narrator actually struck me as a little more progressive than his Flatland society, reflecting Abbott's own views on Victorian treatment of women(and the "criminal classes" represented by irregular polygons). Back to the general subject, the idea of a fourth spatial dimension large enough for rotation of objects is pretty speculative in itself, but another work I might recommend on the subject is The Annotated Alice by Martin Gardner, which discusses varying interpretations of what "looking-glass" matter(either antimatter or oppositely-chiral molecules) would do when in contact with "normal" matter. 69.224.113.5 (talk) 21:10, 26 November 2008 (UTC)

By the way, the "Asimov" story mentioned above is actually Technical Error, also published under the title The Reversed Man, by Arthur C. Clarke. --Anonymous, 02:15 UTC, December 3, 2008.

"Brain Balance" autism treatment

I can't seem to find much about this (http://www.brainbalancecenters.com/) treatment regime, except for posts on autism activism sites. Would this approach be described as 'evidence-based' or 'alternative'? Messiahxi (talk) 18:37, 26 November 2008 (UTC)

If you can't find much, especially on sites like PubMed, that's a very good clue that it's more to the alternative part of the spectrum. -- Aeluwas (talk) 18:40, 26 November 2008 (UTC)

indeed... as is the fact that it was founded by Dr. Robert Melillo, who is apparently a Chiropractic Neurologist. I was just wondering if anyone had specifically heard of this program. Messiahxi (talk) 18:56, 26 November 2008 (UTC)

A quick flip through the site reveals absolutely nothing about what, specifically, they actually DO. For people at the autistic end of the spectrum, some kind of treatment that actually works would be a truly wonderful thing - and clearly the parent of an Autistic kid needs to explore all of the options to help the child out.

But at the more 'normal' end, "curing" Asperger's syndrome is considered by most people who have it (me included) to be a REALLY BAD IDEA. Almost every adult who is at the more mild end of the spectrum will tell you that as bad as the downsides are - they are easily outweighed by the up-sides. If there were a magic pill that would cure my Asperger's - I wouldn't even consider taking it...not for one moment! So I get a little upset when people talk about "curing" children of the syndrome...aside from the fact that this site doesn't look too convincing to me, I worry that they may actually be destroying the potential that Aspergers offers. Aspergers (and Autism) is an actual difference in the structure of the brain - you can't simply use therapy and nutrition and whatever else they do to "fix" that. What you can do is to cause the child to suppress the beneficial things in order to "fit in" - which is a terrible, awful thing to do.

What us Aspies REALLY need is a comprehensive testing program so that "sufferers" can be identified earlier in life - and placed on the appropriate slot in the spectrum (Normal...Mild Aspergers...Severe Aspergers...Autism...Profound Autism). I didn't find out why life seemed so difficult until I was nearly 50 years old! What a SPECTACULAR difference it would have made if I'd known when I was in my early teens...I can't tell you the number of things I screwed up in interpersonal relations simply because I didn't know. Now I do - I positively cringe at some of the things I did that I now know to avoid. Once identified, we need to be taught the set of social skills and body language that everyone else takes for granted (most are mere 'conventions' that are quite teachable to someone with the intense ability to focus that characterises an Aspie). I've been through a 1 week course - and it's INCREDIBLE how much that helped. They didn't try to cure anything - just to tell me what other people know instinctually and apply automatically that I have to learn explicitly and think about consciously. That's why knowing is a HUGE part of what an Aspie needs on a day-to-day basis.

Case in point from yesterday. My kid (who is in college) phones me up at work (which is unusual) and tells me all about some text book that he needs and why he needs it and how he's going to pick it up - and oh, by the way, since we recently moved house, is the billing address on his credit card OK? So I listen carefully, answer the questions he asked, say goodbye and put the phone down. Then - my "training" kicks in. Why on earth did my kid ask me all of that crap? I don't need to know it. Then the alarm bell goes off..."Hold on - this must be one of those 'hidden agenda' things that I'm so useless at spotting!"...so I think hard about what OTHER message was buried in the phone call - and BINGO!...he wants me to offer to pay for the book. The point being that I totally lack that part of the brain that tells me what the other person might be thinking (I've heard this area of the brain called "the mirror neurons" because they function as a copy of the other person's thought processes. I simply don't have the ability to put myself in my son's position of needing to ask for a favor and not wanting to come right out and demand money. (Which is unfortunate - because an Aspie needs to be told exactly what you want because he/she can't know any other way!) But - because I've had the training - I know that when a conversation goes oddly, then there is something I'm missing about how the other person is thinking...and sometimes I can work out what it is and fix it. But when I didn't KNOW I had this problem (or, more exactly - when I didn't know that everyone else DIDN'T have this problem) - I'd never have thought to call my son back and ask if I could pay for the book.

(Of course, from my perspective - I'm just wondering why the heck there has to be all of this machiavellian double-talk going on in the world. If you want me to do something - JUST SAY SO FOR CHRISSAKES!)

SteveBaker (talk) 19:12, 26 November 2008 (UTC)

If it helps you at all, Steve, I'll tell you right now that every time a kid calls home from college, he's looking for you to pay for something, so you may as well just begin your conversation with "how much and how soon?" Matt Deres (talk) 21:26, 26 November 2008 (UTC)

Also, doesn't it seem strange that your son hasn't yet figured out how to get what he wants from you? Even if he wasn't aware of the Asperger's, you'd think (or at least I would) that he would intuitively have figured out what he needed to do? My daughter figured out how to wrap me around her finger in pretty short order. Matt Deres (talk) 21:31, 26 November 2008 (UTC)

Perhaps he has. He did, after all, get his dad to buy the book. APL (talk) 21:43, 26 November 2008 (UTC)

I can’t tell you how many times I’ve wished that people would just say what they mean, and I don’t have Aspergers as far as I know! (the mores the pity) --S.dedalus (talk) 21:37, 26 November 2008 (UTC)

I've wished the same thing, and I have been tested for Aspergers and found not to have it. I have no problem playing the game, but I really wish I didn't have to... --Tango (talk) 21:44, 26 November 2008 (UTC)

Firemaking in the 1700's.

Hello, I was wondering how fires were started and candles were lit in the 18th century. I searched for matches but found they were invented in the 19th century. I have asked a few people and they didn't know but guessed at flint or two sticks, however,I thought this was quite primitive for the 18th century and would like a certain answer to how fires were produced. Thank you. 82.27.54.8 (talk) 19:16, 26 November 2008 (UTC)

They used a tinderbox. —Jeremy (talk) 19:18, 26 November 2008 (UTC)

This was discussed here circa May 19 2008. Link? Edison (talk) 03:43, 27 November 2008 (UTC)

An easy and once common way to light candles, fires, etc, was to use an already lit candle, fire, coals, etc. The question is how did one start a fire when there wasn't a flame or smoldering embers somewhere around already. A minor point, sure, but the most common way to light a candle in the 18th century was probably to use a flame or embers already handy (depending on location and circumstance of course). In earlier times than the 19th century, when starting a fire was more difficult, it was common to "borrow" fire from your neighbor/friend/kith. Making fire might be of interest. Pfly (talk) 06:40, 27 November 2008 (UTC)

Good point. My grandmother lived as a girl in a house where there was no electricity. A collection of rolled up pieces of scrap paper she called " tapers" was kept near the fireplace, and one could be lit from the remaining coals in the fireplace to light a kerosene lamp or a pipe. I supposed this saved the cost of a match. Edison (talk) 17:20, 28 November 2008 (UTC)