Science desk
< December 14	<< Nov \| December \| Jan >>	December 16 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 15

Awesome memory of conductors

When traveling by train, I'm always amazed how the conductors can memorize all of the passengers, at which stations they have boarded the train, weather or not they had already been checked for tickets, etc. I know about the difference between short and long term memory, for example, if we see some light bulbs lighting up for a fraction of a second on a, let's say, 10*10 board, we can tell their positions perfectly after a few seconds. If we leave the room for a few minutes, or we play the game for many more turns, we forget it. However, let's imagine a train with 10 cars and hundreds of passengers. From my experience, the conductors always remember at which station did the passengers board the train, what their destinations are, what price class are they in, and not only based on the seats (they remembered me for example when I moved to another car). So the should have developed some kind of short term memory that lasts at least for a couple of hours? Are they specially trained for it? Or do one needs to be tested for that "special ability" when applying for the job? I've seen many young conductors possessing very good abilities with the tasks described above, so it does not seem to be limited to older personnel with 40+ years of experience. --131.188.3.21 (talk) 15:45, 15 December 2008 (UTC)[reply]

From my experienced the conductor doesn't need to know 'where' you are going, or 'what price' class you are in - all they need to know is they've validated your ticket. It then becomes a different thing - as the conductor you aren't looking for people you've seen, you're looking for people you've not seen. If the person is unfamiliar you ask to check the ticket, you may ocassionally double-check tickets but you also have a few extra thing in your favour: 1) Those who've had their ticket check won't respond to the "tickets please" request 2) Those who've had tickets will likely give you a 'knowing' look and 3) Those who haven't had had their tickets checked will be either A) getting their ticket out/have it ready or B) Trying to avoid eye contact in the hope of avoiding getting checked. Add in all those other factors and whilst it is still an impressive display of memory I don't think it is as special as you'd think. 194.221.133.226 (talk) 16:17, 15 December 2008 (UTC)[reply]

Conductors do get a "feel" for passengers trying it on. I used to work as a buffet steward on the railways, and even in that job one quickly came to recognize the signs of someone trying it on. And I'd add that it is surprisingly easy to remember where a passenger got on, even on a bus train - I suspect that most people are just never in a situation where this skill would be called into play. DuncanHill (talk) 16:27, 15 December 2008 (UTC)[reply]

I wonder whether conductors are good players of bridge and other card games where remembrance of recently-played cards is important. Also, waiters and waitresses must have a good short-term memory so they know which food from the kitchen goes to which table, and to which person at the table. Can that type of memory be developed with experience? As for long-term memory, many successful businessmen have a very good memory. - GlowWorm —Preceding unsigned comment added by 98.17.46.132 (talk) 20:19, 15 December 2008 (UTC)[reply]

(EC with above, didn't know he was gonna talk about cards too...) It comes down to learning how to "differentiate" your memory. Its not merely looking at a face and placing some fact next to it every time; there are levels of memory, where you categorize and sub-categorize. I have been a card-player my whole life, and my wife is often annoyed by how easy it is for me to know exactly which players have played what cards in a game of, say, Spades. I don't just memorize the cards as they come out, I have "registers" in my mind, where I keep track of stuff like which suits have been broken, which suits have been played how many times without being trumped, which trumps have been played, who is out of which suits, etc. Thus, I can get a fairly good sense of what cards each person has played, and what they have left, without actually trying to remember any one specific card or hand; its sort of an "organized" memory, more like a database than a simple list of "Person A played the 4 of diamonds" sort of memorization. Train conductors might use some of the same sorts of "tricks".

There ARE people with scary good memory. Basketball player Jerry Lucas was noted for his freakishly good memory. There are reliable accounts of his being able to quote the New York City phonebook, and other weird memory parlor tricks. --Jayron32.talk.contribs 20:26, 15 December 2008 (UTC)[reply]

An important aid for students to get good grades is good short-term memory (for tests) and good intermediate-term memory (for exams). But I think I read somewhere that persons with a good memory are not good creative thinkers. Maybe their minds are so cluttered with memories that they are unable to associate 2 and 2 to make 5. However, it is good that persons in the medical field remember lots of facts. Good long-term memory is useful in law and other professions too. But to make breakthroughs in medical research or win spectacularly in legal cases, creative thinking is needed – it is necessary to add 2 and 2 to make 5. I believe I also read that those with the highest grades in college perform well but routinely in their profession. - GlowWorm —Preceding unsigned comment added by 98.17.46.132 (talk) 22:46, 15 December 2008 (UTC)[reply]

Good high-school grades and a good SAT score are important factors for getting into college. Students with a very good memory (or a "photographic memory"), and those who put in lots and lots of time studying while in high school, will meet these criteria. Such students are fine for the State colleges. They will make good-quality professionals. However, the "best" colleges, such as Harvard, should be seeking creative thinkers, not memorizers. From what I have heard, the top colleges pay too much attention to the numbers. They also seek those who were high-school student leaders, eager sports participants, and joiners of extra-curricular clubs. However, many great men in science and other creative fields do not fit that category – sometimes they are even loners, introverts, curmudgeons, or Aspies. Henry Thoreau, who went to Harvard, would never get into Harvard today. How to find creative students is a difficult problem, but that should be the goal of top-rated colleges except for such majors as business administration. In fact, I think the top colleges are influenced by businessmen on the college board who are thinking mostly about good business graduates. – GlowWorm —Preceding unsigned comment added by 98.17.46.132 (talk) 23:32, 15 December 2008 (UTC)[reply]

See memristor for another kind of conductor with an awesome memory. — DanielLC 16:46, 17 December 2008 (UTC)[reply]

Thank you for all the interesting answers. I also think now, that there should be some subconscious selection weather something is important or not. If my mind would be focused to interpret the passengers boarding the train, it should be able to memorize them, even if not as accurately as an experienced conductor. For example, I seem to have a good short/term and long term memory, but I'm very bad at medium term. By meeting new people the first time, after a few hours I forget everyone's name. However, if I subconsciously deem someone from the new people as important (a cute lady, for example), I remember nearly every little detail even after many years. --131.188.3.21 (talk) 17:54, 17 December 2008 (UTC)[reply]

The following article deals with unconscious selective memory in elderly people ("the good old days", "those were the days"): http://www.telegraph.co.uk/health/healthnews/3831549/Older-people-really-do-view-past-through-rose-tinted-spectacles.html

—Preceding unsigned comment added by 98.17.46.132 (talk) 15:28, 18 December 2008 (UTC)[reply]

PRIVATELY FUNDED CANCER RESEARCH FACILITIES IN THE U.K.?

I worked at The Burnham Institute in Calfornia,are there any similar research facilities here in the U.K. that carry out research on age,cancer,stem cell and other related sciences? Other than medical colleges that have limited budgets for research. Fluter. —Preceding unsigned comment added by 170.86.15.15 (talk) 15:50, 15 December 2008 (UTC)[reply]

Not a private facility, but I think Cancer Research UK would be a very good place to start. DuncanHill (talk) 16:30, 15 December 2008 (UTC)[reply]

I don't know much about the UK research structure, but I would expect there is a far amount of cancer research going on some of it being mostly or completely privately funded. But this would occur in universities and other general purpose facilities. I'm not sure if there is even a lot of 'medical colleges' in the UK, I believe most are probably a faculty of a university or similar. If you are interested in working in the UK, your better bet may be to look for facilities carrying out research in your specific area of interest and seeing if they have any funding/positions available to take you on. Once you are set up, if you have sufficient experience you could probably apply for a grant from the various private sources available Nil Einne (talk) 10:57, 16 December 2008 (UTC)[reply]

Hippocampal dysplasia.

A simple question really. Well a few querstions. Initally what is hippocampal dysplasia? I know what dysplasia is generally, but in reference to the hippocampus. Secondly, how is it someone gets it? Is it congenital or can you get it through drugs, drink etc. What are the side effects and treatment, prognosis etc? 92.3.53.98 (talk) 19:33, 15 December 2008 (UTC)[reply]

Hippocampal dysplasia literally means immature cells in the hippocampus. It's usually indicative of a neoplastic tumor within the hippocampus but there are other causes, I believe. I can't find any specific information on prognosis but I assume it'd be similar to those of the neoplastic tumors indicated by hippocampal dysplasia. As for signs and symptoms, it's likely that they would revolve around the function of the hippocampus: primarily the memory and senses. Sorry I couldn't be any more specific. —Cyclonenim (talk · contribs · email) 19:51, 15 December 2008 (UTC)[reply]

In neuroanatomy, cortical dysplasia is an abnormality of the microscopic structure of the brain. It doesn't have to be pre-neoplastic (even though that is a common association with the word dysplasia). Cortical dysplasia could be due to a neuronal migration abnormality or due to abnormal growth of cells within an area of the brain. Hippocampal dysplasia can cause abnormal electrical impulses originating from the temporal lobe, resulting in epilepsy (http://www.ncbi.nlm.nih.gov/pubmed/16473127). There are probably both genetic and environmental causes of cortical dysplasia and it could be either congenital in the case of a migration disorder or have onset later in life in the case of an intracranial tumor. Surgical removal of the seizure focus can be required in cases of intractable epilepsy. --Medical geneticist (talk) 20:19, 15 December 2008 (UTC)[reply]

Density

I think Osmium is the densest element but I was wondering if there is a possible answer to what is the densest material overall. Regards. Andy (talk) 19:41, 15 December 2008 (UTC)[reply]

The heaviest material is likely to be the matter inside of the Schwarzschild radius of a black-hole, but this is untestable. The heaviest "normal" material is the material that a Neutron star is made of, which is basically made of unseperated atomic nuclei, and is thus rediculously dense, something like 1,000,000,000,000,000 (one quadrillion) times as dense as water. At such scales, I have heard such conjecture that a cup of the material would weigh more than the whole earth... --Jayron32.talk.contribs 20:16, 15 December 2008 (UTC)[reply]

Remember hearing that, something like a teaspoon weighing 10 billion tons! Wow! Just out of interest, do you know what the densest material on earth is? Andy (talk) 20:27, 15 December 2008 (UTC)[reply]

If you allow *in* Earth, then probably the inner core. I don't know about the surface of Earth, though - it could well be Osmium compounds. --Tango (talk) 20:41, 15 December 2008 (UTC)[reply]

The densest material is likely to be osmium at 22.6 g/cm³. The Earth's inner core (the densest region of Earth generally), by comparison, averages 15 g/cm³. It's possible that isolated pockets of the core might be higher, though. Earth, for what it's worth, is the densest planet in the solar system. — Lomn 20:44, 15 December 2008 (UTC)[reply]

Just to clarify - the Earth has the highest *average* density. Jupiter's core is probably a lot denser than anything on Earth. --Tango (talk) 20:46, 15 December 2008 (UTC)[reply]

Thanks a lot for all your contributions, they are all much appreciated. Andy (talk) 21:26, 15 December 2008 (UTC)[reply]

If we disallow an actual black hole - but allow a neutron star - then I have a better choice! When a star starts to collapse into a black hole - there must come a moment (albeit brief) when it's denser than a neutron star - but does not yet have the density needed to prevent light from escaping. At that brief moment, the density is gonna be higher than a neutron star - but not yet as dense as a black hole. Nothing denser is possible without becoming a black hole - so this is definitely the winner! SteveBaker (talk) 00:48, 16 December 2008 (UTC)[reply]

Should they exist, wouldn't naked singularities be the densest observable objects? (I.e. infinite density.) --Link ^(t•c•m) 06:25, 16 December 2008 (UTC)[reply]

I'd say their density is undefined, rather than infinite. Infinities in physics just mean you are using a formula that doesn't apply in that context. As a star collapses into a black hole there will, however, be a time at which it is arbitrarily dense (I think) - it doesn't collapse to a singularity instantly, it does so in finite time, so even after it is within the event horizon, it still has a well defined density which tends to infinity as (proper) time tends towards some fixed moment. --Tango (talk) 13:45, 16 December 2008 (UTC)[reply]

My knowledge of particle physics is weak but if the conspiracy theorists are partially right and the LHC does (or maybe even has) successfully created a Micro black hole then wouldn't that likely be the the densist material on earth, even though we couldn't actually test for it and wouldn't know it was there? (N.B. Just to be clear, I'm well aware that even if this does happen the earth almost definitely wouldn't be in any danger, that's why I said they would only be partially right) Nil Einne (talk) 10:48, 16 December 2008 (UTC)[reply]

The LHC hasn't done any collisions yet (they only turned on the beam in one direction before it all broke), so there certainly aren't any yet (other than the millions produced every second in the upper atmosphere as they have been for billions of years... [I may be exaggerating, I have no idea how often they are produced]). --Tango (talk) 13:45, 16 December 2008 (UTC)[reply]

On earth you would separate out Os¹⁹⁰, the heaviest isotope to get about a 1% gain in density. I don't know if anyone has done this. Also if you can put the material under pressure, the density could temporarily increase. Graeme Bartlett (talk) 00:52, 16 December 2008 (UTC)[reply]

What about a Quark Star?Trevor Loughlin (talk) 14:57, 16 December 2008 (UTC)[reply]