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bio website vyznev.net
location Helsinki, Finland
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visits member for 3 years
seen Dec 15 at 23:06

I'm a PhD student in biomathematics, working on stochastic individual-based models of evolution in spatially structured populations. My other interests include cryptography, programming games and puzzles, photography and graphic design.

Vote for me in the Mathematics.SE 2014 moderator election!


I'm the main author and maintainer of the Stack Overflow Unofficial Patch (SOUP), a user script for browsers with GreaseMonkey-compatible user script support (Firefox, Chrome, Opera, possibly Safari) that fixes or works around a number of outstanding issues with the Stack Exchange user interface.

I tend to answer a lot more questions than I ask. Some answers I'm rather proud of:

CC-Zero 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.


Nov
13
comment Do biological facts determine when a human fetus is considered alive and human?
@JohnDubya: ... In any case, my point wasn't about whether, or to what extent, sperm and ova are distinct from the diploid life stages preceding and succeeding them, but about whether they count as "alive". It's very hard to come up with an objective definition of "a distinct living organism" that would exclude a human sperm cell without also excluding, say, a drone bee.
Nov
13
comment Do biological facts determine when a human fetus is considered alive and human?
@JohnDubya: Each ovum or sperm cell carries half the DNA of the parent that produced them; when an ovum is fertilized, the resulting embryo inherits half its DNA from the ovum, and half from the sperm. An ovum or a sperm is thus equally related to the parent that produced it, as to the child produced from it. If you consider the child "wholly separate and distinct" from the ovum, then, by the same argument, you should also consider the ovum "wholly separate and distinct" from the parent. (Well, almost. Relatedness gets a little tricky when ploidy changes, as notably seen in social insects.)
Sep
26
comment Why do different pain killers have different effects on people?
NSAIDs are a pretty diverse group of drugs. You might find en.wikipedia.org/wiki/Diclofenac#Mechanism_of_action interesting.
Sep
24
awarded  Autobiographer
Sep
21
awarded  Custodian
Sep
21
reviewed Approve How does isopropyl alcohol disinfect less in higher concentration?
Sep
18
comment Do biological facts determine when a human fetus is considered alive and human?
In fact, by pretty much any sensible definition, the unfertilized ova and sperm are also just as alive as the fertilized embryo is. Just because these haploid gametes make up a relatively small part of the human life cycle doesn't change the fact that they move, they metabolize, and, crucially, they're capable of reproducing (by first fusing into a diploid zygote, which then grows and produces more gametes). Or, as somebody once quipped, "a chicken is an egg's way of producing more eggs."
Sep
4
comment How do birds influence brood sex ratios?
Sperm production bias will, of course, not work in birds since they have a ZW sex chromosome system, not XY. I suppose the female might be able to similarly bias ovum production, though.
Aug
25
awarded  Revival
Aug
17
comment Why isn't vomit corrosive?
@Thorbjørn: At least you can still read the abstract without paid access.
Aug
14
comment Is there any relationship between heartbeat rate and life span of an animal?
In the second plot, getting a "narrow corridor" on a log scale is hardly a surprise. Also, I'm pretty sure that either or both plots must have some of the species labels mixed up (and they both consistently misspell "hamster"). Of course, neither of those issues necessarily invalidate the general claim that short-lived species tend to have faster heart rates (which, given that both traits correlate with body size, is hardly surprising either), but those are the kind of mistakes that proper peer review and competent editors ought to catch. Honestly, I expected more from an Elsevier journal.
Aug
3
awarded  Nice Answer
Jul
4
comment HSL Lightness vs Eye sensitivity
I'm not sure this is really the best possible SE site for this question; my answer below, at least, has very little biology in it. There's no "Colorimetry Stack Exchange", but I'd think this would be on topic e.g. at Graphic Design. Alas, they don't have MathJax... maybe Physics would be a better fit? Or Cognitive Sciences?
Jul
4
answered HSL Lightness vs Eye sensitivity
Jun
12
awarded  Nice Answer
Jun
11
comment How is the fluoride in toothpaste absorbed?
I'm a bit dubious about that "more poisonous than lead" quote: it's repeated (in various mutated forms) on many anti-fluoridation websites, but I wasn't able to find anything like it in the claimed source (which, apparently, is actually a book, not a journal issue). That said, Google provides only a rather inconvenient form of snippet search access to the book, so, without an actual copy, I can't be quite 100% sure that it's bogus.
Jun
11
answered How is the fluoride in toothpaste absorbed?
May
25
comment How does yeast dissolve in sugar?
If if you find that impressive, try baking something that calls for a mashed banana. It's typically listed as a liquid ingredient for a reason.
Mar
21
comment How do I calculate the change in allele frequency in a haploid population under selection?
Ps. As a mathematician, I'd like to register my objection to using the notation $\frac{dx}{dt}$ for "allele frequency change per generation"; it properly denotes the rate of allele frequency change over time (presumably in a continuously breeding population, for such a rate to be well defined). Even if we measure time in (average) generations, it's not hard to come up with examples where the two are not equal.
Mar
21
comment How do I calculate the change in allele frequency in a haploid population under selection?
Here's a simple consistency check to show that $\Delta x = \frac{x}{1-sy}$ can't possibly be the right answer: in a pure monomorphic $A_1$ population, there obviously cannot be any change in allele frequencies through selection, so $x = 1$ should imply $\Delta x = 0$. Your formula, however, yields $\Delta x = \frac11 = 1$ in that case.