Power Saving Fish

Its not just a problem for cell phones. [Link]

Fish that use electric fields to sense their environments dim their signals to save energy during the day when they are resting.

Sternopygus macrurus, a South American river fish, is a natural practitioner of energy efficiency. It can reshape the charged-molecule channels in its electricity-producing cells to tone down its electrical signature within a matter of minutes.

“This is a really expensive signal to produce. The fish is using up a lot of its energy budget,” said neurobiologist Michael Markham at the University of Texas at Austin, lead author of a paper in PLoS Biology on the fish. “These animals are saving energy by reducing the strength of the signal when they are not active.”

Thousands of fish and other oceanic creatures use electrical fields to help them perceive their environments. The most famous is the electric eel, which a colleague of Markham’s termed “a frog with a cattle prod attached,” but most animals use the electrical signals in more subtle ways.

The fish’s standard electrical signal runs at 100 hertz; if you turn the electrical signal into sound, it sounds like a high whine. In laboratory experiments, the fish can detect tiny bugs half a centimeter wide and easily navigate obstacles by detecting the changes the objects cause in the electrical field.

Other fish put out different types of electrical fields, some of which vary a lot more. Markham’s team chose S. macrurus specifically because its discharge is fairly regular.

All fish generate electricity with a specialized type of cell called an electrocyte. These cells can generate current by manipulating the amount of charged sodium and potassium ions that they allow to flow into and out of themselves. An electrical current propagates on the membrane of the cell as a result. Thousands of cells combine to generate the 5 millivolts per centimeter electrical field the fish uses. By using fewer sodium channels, the signal gets dimmed and energy is conserved.

“The wave form of the electric signal changes and at the level of the individual cell, it is changing its discharge,” Markham said. “This is the first time in a vertebrate animal that you can show such a clear connection between an animal’s behavior and the changes at the molecular level.”

A brief History of US patents

Nice interactive application shows time and place of some the most important patents of our time registered at the USPTO. [Link]

Hubble 2.0

New images from the newly refurbished Hubble telescope. Click for huge (~6 MB) images. The top 100 images along with some good commentary here.

 

This celestial object looks like a delicate butterfly. But it is far from serene.

What resemble dainty butterfly wings are actually roiling cauldrons of gas heated to nearly 20 000 degrees Celsius. The gas is tearing across space at more than 950 000 kilometers per hour — fast enough to travel from Earth to the Moon in 24 minutes!

A dying star that was once about five times the mass of the Sun is at the centre of this fury. It has ejected its envelope of gases and is now unleashing a stream of ultraviolet radiation that is making the cast-off material glow. This object is an example of a planetary nebula, so-named because many of them have a round appearance resembling that of a planet when viewed through a small telescope.

Appearing like a winged fairy-tale creature poised on a pedestal, this object is actually a billowing tower of cold gas and dust rising from a stellar nursery called the Eagle Nebula. The soaring tower is 9.5 light-years or about 90 trillion kilometers high, about twice the distance from our Sun to the next nearest star.

Stars in the Eagle Nebula are born in clouds of cold hydrogen gas that reside in chaotic neighbourhoods, where energy from young stars sculpts fantasy-like landscapes in the gas. The tower may be a giant incubator for those newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar.

The starlight also is responsible for illuminating the tower's rough surface. Ghostly streamers of gas can be seen boiling off this surface, creating the haze around the structure and highlighting its three-dimensional shape. The column is silhouetted against the background glow of more distant gas.

The edge of the dark hydrogen cloud at the top of the tower is resisting erosion, in a manner similar to that of brush among a field of prairie grass that is being swept up by fire. The fire quickly burns the grass but slows down when it encounters the dense brush. In this celestial case, thick clouds of hydrogen gas and dust have survived longer than their surroundings in the face of a blast of ultraviolet light from the hot, young stars.

Inside the gaseous tower, stars may be forming. Some of those stars may have been created by dense gas collapsing under gravity. Other stars may be forming due to pressure from gas that has been heated by the neighbouring hot stars.

TED: A strange, extraordinary talk on creativity

 

Business of Software: Joel Spolsky on How to be No. 1

Joel Spolsky talking about how to make software that makes people happy. Funny and interesting.

TED: How to measure success

Alain de Botton: Can anyone really achieve anything they want?

How to build a BackBlaze Storage Pod

BackBlaze claims to be the lowest cost cloud backup service providers. They’ve put the complete design of their standard 1 petabyte storage pod online, instead of treating it as a trade secret. The motivation for sharing the design is that if someone comes up with an improvement, they will share it with Backblaze and their business will become more efficient. [Link]

At Backblaze, we provide unlimited storage to our customers for only $5 per month, so we had to figure out how to store hundreds of petabytes of customer data in a reliable, scalable way—and keep our costs low. After looking at several overpriced commercial solutions, we decided to build our own custom Backblaze Storage Pods: 67 terabyte 4U servers for $7,867.

In this post, we’ll share how to make one of these storage pods, and you’re welcome to use this design. Our hope is that by sharing, others can benefit and, ultimately, refine this concept and send improvements back to us. Evolving and lowering costs is critical to our continuing success at Backblaze.