Cumulative General Science/Technology Quiz

[Falcon02]

But giving antibiotics for the placebo effect, that's just scary.

That's why they have sugar pills and what not (ie. real placebos), but agreed.

Also, I think I'd expand it from just the eldarly to anyone with a weakened immune system, for whatever reason (ie. infant, just fought off the plague, whatnot). Since their more likely to have their immune system overwhelmed by the cold/flu AND something else.

 

[peter grimes]

Maybe it's only for people with severely weakened immune systems - people undergoing cancer treatments, for example.

I was also thinking it may have to do with pregnancy, but I can't imagine a scenario (other than severely compromised immune system) where that would be the lesser of all evils

 

[Brighteye]

That's why they have sugar pills and what not (ie. real placebos), but agreed.

Also, I think I'd expand it from just the eldarly to anyone with a weakened immune system, for whatever reason (ie. infant, just fought off the plague, whatnot). Since their more likely to have their immune system overwhelmed by the cold/flu AND something else.

I'll give it here. I was actually thinking of severe asthmatics, who are peculiarly susceptible to lung infections, and for whom the antibiotics are a sensible prophylactic. I've known asthmatics be prescribed antibiotics for a cold for this reason, but the same will of course apply to cancer patients and so on, who will also be susceptible to opportunistic infections.

 

[StarWorms]

I don't fully understand the question, but flu jabs are given to high risk people which include the elderly, those with weak immune systems and people who have contact with a lot of people (eg GPs). The idea of prescribing them the antiviral drugs are obviously to prevent the influenza virus from functioning within the body often by blocking neurominidase and haemogluttinin activity.

 

[Falcon02]

I'll give it here. I was actually thinking of severe asthmatics, who are peculiarly susceptible to lung infections, and for whom the antibiotics are a sensible prophylactic. I've known asthmatics be prescribed antibiotics for a cold for this reason, but the same will of course apply to cancer patients and so on, who will also be susceptible to opportunistic infections.

I'll take that as a it's my turn to ask a question.


What are Quaternions as they relate to spacecraft navigation, and what mathematical problem makes them so important?

 

[Dann]

I have absolutely no idea.

 

[Falcon02]

Was hoping at least Niklas would have some insight into this, given it's mathmatical basis.

 

[Niklas]

Sorry, I've never heard of Quaternions.

 

[Serutan]

They're needed because you have to do vector math for all the forces involved?

 

[Truronian]

I've heard of them... they're like a 4D version of the complex numbers IIR. Not sure how they're used though...

 

[Niklas]

I've heard of them... they're like a 4D version of the complex numbers IIR. Not sure how they're used though...

Ah right, that does ring a bell. Aren't they used in computer graphics in
some way..? But for space faring? No idea.

Was hoping at least Niklas would have some insight into this, given it's mathmatical basis.

I should note that I'm not really a mathematician, I'm a computer scientist, so unless some particular maths has its uses in CS I probably haven't heard of it. That's why I know about P=NP, and GMR in HDDs, and have a vague idea that quaternions have something to do with computer graphics.

 

[Falcon02]

Truronian got the closest.

http://en.wikipedia.org/wiki/Quaternion

Yes they are a 4 dimensional extension of complex numbers. As such in general you can use Quaternions to translate 3 dimensional space into 4 dimensional space.

In Satellites quaternions are often used for attitude (directional pointing) control. Traditional 3 dimensional angles (ie. Euler Angles) have a problem with them. Think about Azimuth, on just about any location on the earth I can tell you exactly the direction I'm facing by giving my angle away from true north in the clockwise direction. However if I'm at the north pole what direction am I facing? No matter what direction I face I'm pointing south (180°). The direction I'm pointing is undefined (which can cause a control system to fail). This is more or less "Gimbal Lock" (see movie Apollo 13) where one dimension becomes undefined because of the orientation one or more of the others.

Use of Quaternions for attitude propagation help eliminate the likelihood of this happening. On a side note, I've seen some sources say it eliminates the chances for such a lock up, and other say it only reduces the probability of it occurring. I'm not sure which is actually true.

Truronian your turn.

 

[Truronian]

Ok, sticking with maths...

Annulus is to torus as Mobius strip is to _ _ _ _ _ _?

 

[Niklas]

Donut?

 

[Mirc]

Klein bottle?

(oh and really sorry if this is a totally wrong answer, I'm a music student after all. )

 

[brennan]

Still a torus? A mobius strip is essentially a twisted annulus.

 

[peter grimes]

as Mobius strip is to a plane?

I suppose it would help if I actually knew what an annulus is

 

[Mirc]

Annulus - Latin for "ring" (also the root word for the word for "ring" in all Romance languages today).

Hence the mathematical term meaning an object of the shape of a ring.

 

[peter grimes]

I'm aware of the word's etymology (i had 12 years of latin), but I didn't know what it specifically referred to in a mathematical or geometric context.

I suppose I'd have answered something different, but I still don't have any idea

 

[Mirc]

Sorry then. I just assumed you don't know. Great to find more people that still study Latin.