Tag: science

Fruit Flies, Fighter Jets Use Similar Evasive Tactics When Attacked

Fruit Flies, Fighter Jets Use Similar Evasive Tactics When Attacked

When startled by predators, tiny fruit flies respond like fighter jets – employing screaming-fast banked turns to evade attacks. Researchers at the University of Washington used an array of high-speed video cameras operating at 7,500 frames a second to capture the wing and body motion of flies after they encountered a looming image of an approaching predator (abstract). ‘We discovered that fruit flies alter course in less than one one-hundredth of a second, 50 times faster than we blink our eyes, and which is faster than we ever imagined.’ In the midst of a banked turn, the flies can roll on their sides 90 degrees or more, almost flying upside down at times, said Florian Muijres, a UW postdoctoral researcher and lead author of the paper. ‘These flies normally flap their wings 200 times a second and, in almost a single wing beat, the animal can reorient its body to generate a force away from the threatening stimulus and then continues to accelerate,’ he said.

First there was the anternet, and now this?  It almost sounds like humans a giant insects…

The anternet

Stanford researchers discover the ‘anternet’

Transmission Control Protocol, or TCP, is an algorithm that manages data congestion on the Internet, and as such was integral in allowing the early web to scale up from a few dozen nodes to the billions in use today. Here’s how it works: As a source, A, transfers a file to a destination, B, the file is broken into numbered packets. When B receives each packet, it sends an acknowledgment, or an ack, to A, that the packet arrived.

This feedback loop allows TCP to run congestion avoidance: If acks return at a slower rate than the data was sent out, that indicates that there is little bandwidth available, and the source throttles data transmission down accordingly. If acks return quickly, the source boosts its transmission speed. The process determines how much bandwidth is available and throttles data transmission accordingly.

It turns out that harvester ants (Pogonomyrmex barbatus) behave nearly the same way when searching for food. Gordon has found that the rate at which harvester ants – which forage for seeds as individuals – leave the nest to search for food corresponds to food availability.

A forager won’t return to the nest until it finds food. If seeds are plentiful, foragers return faster, and more ants leave the nest to forage. If, however, ants begin returning empty handed, the search is slowed, and perhaps called off.

Prabhakar wrote an ant algorithm to predict foraging behavior depending on the amount of food – i.e., bandwidth – available. Gordon’s experiments manipulate the rate of forager return. Working with Stanford student Katie Dektar, they found that the TCP-influenced algorithm almost exactly matched the ant behavior found in Gordon’s experiments.

two to the power of one hundred

Here is an excellent visualization of 2 to the power of 100.  If you take a piece of paper which is 0.1 mm thick, cut it in half and place one half on top of the other, then cut the stack in half and place half over the other half, and then repeat it 98 more times … how high is your stack of paper going to be? Think.  BOOM!  13.7 billion light years.  Here is a breakdown of how fast it gets there.

Just beautiful.