Check out this summary of results on aging in nematodes. The layman’s summary is this:
Aging is thought to be due to accumulated damage. As we age our bodies get lots of microscopic injuries and accumulated cellular damage. Over time it adds up and our bodies break down and we die. This is the prevailing hypothsis because it’s easy to see the mechanism for how it came to evolve.
An alternate hypothesis is that our genes dictate that we age and die, and it’s programmed into us. So rather than breaking down, aging is the result of changes in metabolic regulation.
This study finds evidence supporting the latter model, which is pretty interesting. To summarize their experiment they used gene-chips to exhaustively search for genes that change their expression level in old worms, and linked many of them to a single regulatory protein (transcription factor). Then they tried to put stresses on young worms to see if they could increase the level of this transcription factor, effectively making the worm age faster. They were not able to, which indicates that the transcription factor levels are not a function of stress. Of course, this is only true if they were using the “right” stresses on the worms.
In any case, I’m always excited to see work done that supports any sort of programmed-senescence model, because it points toward the possibility of regulating aging by only tweaking a few things.
Ok, this is a departure from my normal biotech / research stuff, but there’s so much internet-stupidity going on that I want to post something about basic financial math.
Everyone has their panties in a bunch because the iPhone 3G costs less up front but “costs more over the life of the contract!” This is a bunch of crap, and people who believe that are also going to get screwed when they buy a car or a house.
Here’s the thing: you cannot compare 2 financial deals simply by adding up all of the payments and seeing which is bigger, because there is such a thing as the “time value of money.”
Continue reading ‘iPhone 3G costs are unchanged over first gen’
I wanted to share this great youtube video demonstrating a classic kitchen-science non-newtonian fluid: cornstarch and water. The creator puts this mixture on a cookie plate and presses the plate against a subwoofer. The result is pretty great!
A little background on newtonian fluids
In a newtonian fluid the shear rate (rate of flow) is directly proportional to the shear force (how hard you push on the liquid), and the constant of proportionality is the viscosity. So if you double the shear force, you double the shear rate. In a non-newtonian fluid that’s not true, and it can be untrue in different ways. The most straightforward comment is that you can get a non newtonian fluid if the viscosity is not constant. In the case of cornstarch and water you have a fluid where the harder you shear it the more viscous it gets. Compare this to water where the harder you shear it the faster it flows.
Wikipedia has a decent article on non newtonian fluids that you could check out.