Monday, March 31, 2008

Build your own Rebreather for $100 ...

... using a hot water bottle: A HOT WATER BOTTLE PENDULUM
Warning Warning Warning


You can die from too much oxygen by using pure oxygen below 20 feet of seawater. You can die from too little oxygen. You can drown. Screw up and you are likely to die. When you enter the water, you are on your own, even if a buddy is nearby. You alone must make the decision that you are capable of using a rebreather, you are up to the dive, and that your equipment is up to the dive. Even extensive open circuit experience will not prepare you for the details inherent with staying alive underwater on a rebreather. If you have any concerns about your abilities, take a course or do not dive. If you are foolish enough to dive rebreathers, be aware that it is a case of Evolution in Action. It is an effective sorting out process that has created many unhappy widows, mothers, and children. I recommend against it. This project is described for your amusement only. It is not the intent of the author that you build one of these and go out and kill yourself. As I have shown it, if you take the mouthpiece out of your mouth, water will flow in filling the scrubber, and your next breath is a caustic cocktail. If you don't know what you are doing, don't try this one at home. If you know what you are doing, I am sure you have a rig that makes this one look childish.

Information Storage in the Brain

Compartmentalized dendritic plasticity and input feature storage in neurons in Nature.
Although information storage in the central nervous system is thought to be primarily mediated by various forms of synaptic plasticity, other mechanisms, such as modifications in membrane excitability, are available. Local dendritic spikes are nonlinear voltage events that are initiated within dendritic branches by spatially clustered and temporally synchronous synaptic input. That local spikes selectively respond only to appropriately correlated input allows them to function as input feature detectors and potentially as powerful information storage mechanisms. However, it is currently unknown whether any effective form of local dendritic spike plasticity exists. Here we show that the coupling between local dendritic spikes and the soma of rat hippocampal CA1 pyramidal neurons can be modified in a branch-specific manner through an N-methyl-d-aspartate receptor (NMDAR)-dependent regulation of dendritic Kv4.2 potassium channels. These data suggest that compartmentalized changes in branch excitability could store multiple complex features of synaptic input, such as their spatio-temporal correlation. We propose that this 'branch strength potentiation' represents a previously unknown form of information storage that is distinct from that produced by changes in synaptic efficacy both at the mechanistic level and in the type of information stored.

Traffic Jams Just Happen

Traffic Jams Happen, Get Used to It in Science Magazine.

Too many cars equals a traffic jam, even without an external cause.
Credit: Mathematical Society of Traffic Flow

Precision Clocks

A Milestone in Time Keeping in Science Magazine.
Researchers have made atomic clocks so precise that effects of general relativity are on the verge of complicating the concept of keeping time.

So much for "junk DNA"

Only 1-2% of the DNA in humans and other higher organisms appears to code for proteins. But the remaining so-called "junk DNA" may be transribed into RNA with numerous functions.
The Eukaryotic Genome as an RNA Machine in Science Magazine.
The past few years have revealed that the genomes of all studied eukaryotes are almost entirely transcribed, generating an enormous number of non–protein-coding RNAs (ncRNAs). In parallel, it is increasingly evident that many of these RNAs have regulatory functions. Here, we highlight recent advances that illustrate the diversity of ncRNA control of genome dynamics, cell biology, and developmental programming.