2,865 reputation
1119
bio website vyznev.net
location Helsinki, Finland
age
visits member for 2 years, 8 months
seen 18 mins ago

I like programming in Perl and C. I know Java and PHP too (I'm a MediaWiki developer), but I can't really say I like them. I keep meaning to learn Python some day, but never seem to get around to it.

I'm working on a Ph.D. in biomathematics. I also like programming puzzles and cryptography.

Please consider any (original) code I post to Stack Overflow (and other Stack Exchange sites) to be released under CC-Zero unless stated otherwise. You may do whatever you want with it and don't have to credit me in any way, although of course that would be nice.


Dec
16
answered How to measure resistance of a piece of wire?
Dec
16
awarded  Civic Duty
Dec
16
comment How to measure resistance of a piece of wire?
@BrandonEnright: So use insulated wire?
Dec
1
comment Rotation of a slipping ladder
@ja72: Perhaps we're coming from different viewpoints here. I agree that the DoF reduction trick is neat here (and gave you a +1 for it), but coming from a numerics background, for general use I'd rather prefer a representation of motion that a) did not change in the absence of external forces, b) worked for all rotation rates, including zero, and c) was easy to (approximately) integrate over time. Translation + rotation around the CoM fits those criteria.
Dec
1
comment Rotation of a slipping ladder
@ja72: Only if you insist on describing the (instantaneous) motion as a pure rotation, rather than as a rotation plus a translation. Admittedly, that's what the OP seems to be asking for (since otherwise their question doesn't make much sense), but in general it doesn't seem to me like a very useful way to model rigid body dynamics.
Nov
29
comment Is there a way for an astronaut to rotate?
@EmilioPisanty: Yeah, but it's about as close an approximation as you can get without actually going into space. In practice, those chairs tend to have pretty low friction (at least if well maintained), so unless you do the exercise at a snail's pace, it can be mostly neglected. (As a double check, you can try holding the object at a constant distance, but moving it left and right at different speeds. If you don't observe any significant net rotation, that means the effect of friction was negligible.)
Oct
22
awarded  Nice Answer
Oct
12
answered Why in Newton's law of gravity, we do $M_1 \times M_2$ and not $M_1 + M_2$?
Sep
16
comment What is vacuum to DC flow?
Does a vacuum tube still count as "common circuitry"? Because, you know...
Sep
13
comment What is the difference between the Balmer series of hydrogen and deuterium?
A minor nitpick on an otherwise excellent answer: while high concentrations of heavy water do indeed inhibit eukaryotic cell division, at least some bacteria and other prokaryotes will grow just fine even in 100% heavy water. That's how perdeuterated biochemicals are produced.
Sep
11
awarded  Good Answer
Sep
9
awarded  Nice Answer
Sep
9
answered Are the air particles in today's wind on earth (more or less) the same as the air 2/3 billion years ago?
Sep
3
awarded  Nice Answer
Sep
2
comment Why does blowing on a candle put it out but sucking doesn't?
Also related: What happens, if a rocket is filled with a vacuum instead of high pressured air?
Aug
30
comment Why is a hard sphere gas correlated?
@MichaelBrown: No, of course I don't mind. My answer is really just an extension of gatsu's, anyway.
Aug
29
awarded  Enlightened
Aug
29
awarded  Guru
Aug
29
answered Why is a hard sphere gas correlated?
Aug
29
comment Why is a hard sphere gas correlated?
@MichaelBrown: I guess the point it that if the particles are less than two diameters apart, then the closer they are the smaller the gap between them is, and so the more room there is for other particles. Basically, looking at the possible locations of the centers of each particle, each of them excludes other particles from a sphere of radius $a$ around it. But if you bring two particles closer than $2a$ apart, then their exclusion radii overlap, leaving more room for other particles elsewhere.