A
Anonymous
Guest
That's it! 
Random trivia
- Thread starter StrangerInAStrangeLand
- Start date
Albie
Keeping an open eye on the Weeping Angels.
I know that the only constant is the speed of light in a vacuum, but other factors can slow/speed it down/up (gravity, etc). I also know that Einsteins E=MC[sup]2[/sup] theory had C[sup]2[/sup] as the speed of light in a vacuum - so, was it Einstein, or is that too obvious?
ABandOn
.:The Final Frontier:.
Albie said:
Albie, you're on the right way, Einstein stated that nothing can move faster than light in a vacuum, but prior to him, someone else found out that the speed can be slowed down depending on the medium (ie. air or water) in which the light travels. It's just a matter of different "refractive indexes"
A
Anonymous
Guest
Could it be Cerenkov? After all there's an effect that bears his name when particles go faster than light in a given medium...
ABandOn
.:The Final Frontier:.
Maverick said:
No Mav, this scientist "only" measured the speed of light in the air and then in the water and compared them
The discovery was done in the middle of XIX sec. and revalued the Huygens' ondulatory theory of light in opposite to the newer (at that time) Newton's corpusculary theory.
A
Anonymous
Guest
Both Léon Foucault and Michael Faraday have experimented on the nature and speed of light in the 19th Century, so I suppose it must be one of those two.
Although it's obvious that Adrian Smith found out long before, as he created light himself.
Although it's obvious that Adrian Smith found out long before, as he created light himself.
Albie
Keeping an open eye on the Weeping Angels.
Pierre-Simon Laplace talked of Black Holes (more or less suggesting the same as what John Michell stated) and that light could not escape them because of its density (hence slowed down). This also suggested that light would be more of a wave (rather than Newton's little particles theory) because they were "bent" as they passed the dark star. This was around the time of Newtons theory been new, I think. Was it him?
Greatly influenced by H's work, of course.
Greatly influenced by H's work, of course.
ABandOn
.:The Final Frontier:.
As rightly guessed by Mav, the right answer is Adr...err...Léon Foucault
Although his most known experiment was the one involving the famous pendulum to demonstrate the Earth rotation around its own axis, he also managed to refine the method used by his colleague Hippolyte Fizeau to determine the speed of light in the air and the result was the most accurate (with an earthbound apparatus) for that period. Both the two scientists prosecuted the works of François Arago arriving at the conclusion that the light traveled slower in water than in air, but only Focault was able to demonstrate it with his best developed apparatus, suitable to calculate the speed of light through water.
For those who are interested to deepen their knowledge about it:
http://micro.magnet.fsu.edu/primer/ligh ... light.html
http://scienceworld.wolfram.com/biography/Foucault.html
http://en.wikipedia.org/wiki/Speed_of_l ... d_of_light
Although his most known experiment was the one involving the famous pendulum to demonstrate the Earth rotation around its own axis, he also managed to refine the method used by his colleague Hippolyte Fizeau to determine the speed of light in the air and the result was the most accurate (with an earthbound apparatus) for that period. Both the two scientists prosecuted the works of François Arago arriving at the conclusion that the light traveled slower in water than in air, but only Focault was able to demonstrate it with his best developed apparatus, suitable to calculate the speed of light through water.
For those who are interested to deepen their knowledge about it:
http://micro.magnet.fsu.edu/primer/ligh ... light.html
http://scienceworld.wolfram.com/biography/Foucault.html
http://en.wikipedia.org/wiki/Speed_of_l ... d_of_light
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Anonymous
Guest
I suppose I was only half right, as I gave two possible answers without being sure of which one was the right one. 
Anyway, I suppose it's my turn to ask a question. This one should please both scientists and historians.
Which non-pathogenic bacterium has been responsible for at least as many human deaths than most pathogenic ones, and why (if it doesn't cause any disease)?
Anyway, I suppose it's my turn to ask a question. This one should please both scientists and historians.
Which non-pathogenic bacterium has been responsible for at least as many human deaths than most pathogenic ones, and why (if it doesn't cause any disease)?
A
Anonymous
Guest
Nope. Food poisoning is essentially caused by toxins produced by microorganisms, classifying those as pathogenic.
I'll give you a Maiden-related hint: Alexander the Great wouldn't have been so great without a bit of help from this particular bug.
I'll give you a Maiden-related hint: Alexander the Great wouldn't have been so great without a bit of help from this particular bug.
Albie
Keeping an open eye on the Weeping Angels.
Far be it for me to comment on history, but did Alexander make himself "Great" by using some "germ warfare" and therefore opposition armies would so readily surrender to it? Or did he die from this bacterium and make people more aware of it (sort of the reason why some folk are named[sup]1[/sup] after illnesses/diseases/etc.)?
Again, I hope to prompt the more educated in this field to think of an answer to this by my questioning - rather than me have several stabs in the dark before I eventually get there!
[sup]1[/sup] I do remember a great put down quote once - who it was directed at and by who spoke it, I cannot tell - but it said: I hope you fall ill to a disease that has not been found and they name it after you!
Again, I hope to prompt the more educated in this field to think of an answer to this by my questioning - rather than me have several stabs in the dark before I eventually get there!
[sup]1[/sup] I do remember a great put down quote once - who it was directed at and by who spoke it, I cannot tell - but it said: I hope you fall ill to a disease that has not been found and they name it after you!
ABandOn
.:The Final Frontier:.
Monas prodigiosa, otherwise called Serratia marcescens?
Just before giving up, I found an article (in italian) about relationships (made of endless adaptation) between microorganisms and man, and it also talked about the major historical events in which this bacterium is involved;
It follows an excerpt of "Studies on bacterial pigmentation", of Roger D. Reid:
"In 332 B C., during the siege of Tyre by Alexander and his army of Macedonians, the soldiery became greatly concerned by the appearance of blood-like droplets on bread as it was broken. So great was the alarm that the soldiers and king alike were about to give up the siege since they considered this phenomena as a portent of their distruction. Upon having this brought to his attention, Aristander, one of the king's most skillfull soothsayers, interpreted it to mean that since the droplets of blood were on the inside of the loaf, it indicated destruction for those within the walls. Taking courage from these interpretations, the Macedonians continued their siege and the city of Tyre fell.
To the modern scientist and bacteriologist, this "miracle" can have but one clear and logical explanation. The growth of what is now known as Serratia marcescens, the red pigmented bacterium which grows profusely on bread and even today causes what is commonly called "bloody bread"."
Clearly, in absence of a scientific explanation, phenomena as blood flowing from hosts were taken as miracles and led to some sort of religious fanatism, at the point that "this minute and harmless saprophyte has been responsible for many sleepless nights, needless murders and executions and important pages in history".
Just before giving up, I found an article (in italian) about relationships (made of endless adaptation) between microorganisms and man, and it also talked about the major historical events in which this bacterium is involved;
It follows an excerpt of "Studies on bacterial pigmentation", of Roger D. Reid:
"In 332 B C., during the siege of Tyre by Alexander and his army of Macedonians, the soldiery became greatly concerned by the appearance of blood-like droplets on bread as it was broken. So great was the alarm that the soldiers and king alike were about to give up the siege since they considered this phenomena as a portent of their distruction. Upon having this brought to his attention, Aristander, one of the king's most skillfull soothsayers, interpreted it to mean that since the droplets of blood were on the inside of the loaf, it indicated destruction for those within the walls. Taking courage from these interpretations, the Macedonians continued their siege and the city of Tyre fell.
To the modern scientist and bacteriologist, this "miracle" can have but one clear and logical explanation. The growth of what is now known as Serratia marcescens, the red pigmented bacterium which grows profusely on bread and even today causes what is commonly called "bloody bread"."
Clearly, in absence of a scientific explanation, phenomena as blood flowing from hosts were taken as miracles and led to some sort of religious fanatism, at the point that "this minute and harmless saprophyte has been responsible for many sleepless nights, needless murders and executions and important pages in history".
A
Anonymous
Guest
ABandOn is right and gets a cookie!
Formerly known as Bacillus prodigiosus, my dear friend Serratia marcescens (we've worked together for a few years
) produces a pigment called 'prodigiosin' that makes the colonies look like droplets of blood. As she likes starch a lot, you can often find her growing in bread, holy wafers, and even polenta.
This bacterium has had a major historical impact, as you said during Alexander's conquest eastwards, but also in Middle-Ages Europe where the apparition of 'blood' on holy wafers was considered a 'sign' and led to the murder of countless Jews, 'witches', and various other kinds of 'heretics'.
Nowadays, this phenomenon occurs less often, but Serratia is often responsible of nosocomial (hospital-related) infections and tends to bother people who have either a depressed immune system or an already established infection. Serratia is not herself pathogenic, but she is an opportunist and has a tendency to accompany a primary infection when she finds one.
As a microbiologist, I would like to stress that, despite her historical impact and her appearance in modern hospital wards, Serratia is innocent! She's never voluntarily hurt anyone and was merely the vitim of Man's twisted evil mind. She's been a major partner in my career and she'll always remain close to my heart.
Serratia, I love you!
Formerly known as Bacillus prodigiosus, my dear friend Serratia marcescens (we've worked together for a few years
) produces a pigment called 'prodigiosin' that makes the colonies look like droplets of blood. As she likes starch a lot, you can often find her growing in bread, holy wafers, and even polenta.This bacterium has had a major historical impact, as you said during Alexander's conquest eastwards, but also in Middle-Ages Europe where the apparition of 'blood' on holy wafers was considered a 'sign' and led to the murder of countless Jews, 'witches', and various other kinds of 'heretics'.
Nowadays, this phenomenon occurs less often, but Serratia is often responsible of nosocomial (hospital-related) infections and tends to bother people who have either a depressed immune system or an already established infection. Serratia is not herself pathogenic, but she is an opportunist and has a tendency to accompany a primary infection when she finds one.
As a microbiologist, I would like to stress that, despite her historical impact and her appearance in modern hospital wards, Serratia is innocent! She's never voluntarily hurt anyone and was merely the vitim of Man's twisted evil mind. She's been a major partner in my career and she'll always remain close to my heart.
Serratia, I love you!
A
Anonymous
Guest
Interesting link, ABandOn.
It's nice to see love of learning and expertise become one. Have a praise for that Mav, from your favourite bug.Maverick said:
ABandOn
.:The Final Frontier:.
Serratia said:
Thanks
Maverick said:
Yes Mav, the article I found (taken from an italian newspaper) talks just about those infections in hospitals and ends saying that:
"It's the proof that public health organizations should begin to think about the relationship between man and microbes in darwinian terms, ie. understanding that microorganisms answers to advances in medicine adopting adaptive strategies that let them colonize new places and modify their pathogenicity. Otherwise, we'll pay again high prices in terms of human lives, even in the developed countries where infectious diseases are no more a serious emergency."
(sorry for the poor translation
)Anyway, time for another question?
This is very simple, for those who have some familiarity with signal processing
Can you name the (undesired) phenomenon that happens when a band-limited signal is sampled at a lower rate than the Nyquist frequency?
Mmm...Donuts
Trooper
Is it aliasing? (The static distortion of digital sound due to low sample rate?)
ABandOn
.:The Final Frontier:.
Mmm...Donuts said:
Yes, it is
To correctly reconstruct a continue time signal from its sampled version, the original signal has to be both band limited ( -B < f < B ) and sampled at least at Nyquist frequency, that is 2B, or aliasing distortion will occur in the reconstructed signal.
http://en.wikipedia.org/wiki/Aliasing
http://www.efunda.com/DesignStandards/s ... sing_A.gif
Mmm...Donuts
Trooper
What was the largest prison breakout of POWS in Australia during WW2?