You're right that a significant issue with noise cancellation is the dynamic range / resolution of the reciever. A lock-in amplifier does just the job:
http://en.wikipedia.org/wiki/Lock-in_amplifier [wikipedia.org]

Lock-in amps are very nice for very specific tasks, like trying to measure very faint signals which would ordinarily be swamped by noise, but they don't fit in to communication systems. The principal of a lock-in amplifier relies on correlating an unknown signal with a known modulating signal over many measurements, meaning that the transmitter has to transmit the same thing over and over again, which completely defeats the purpose of trying to increase wireless data throughput.

You're correct in identifying dynamic range as one of the major issues here. An A2D with an extremely high number of bits would help, as you could recognize both the faint and large signals simultaneously, and with prior knowledge of the large transmitted signal it could be removed from the data.

But there is another issue, which is the dynamic range of the RF hardware itself. Their experiments were conducted at 0dBm (1mW) transmit power, but that is not at all realistic if you want to get decent range, a more realistic power for longer range would be 10-100mW. With 20dB (factor of 100) cancellation there is then up to 1mW heading in to the receiver, which is way way too much for typical RF CMOS, and even for typical SiGe receiver chips, the output will be completely garbled by distortion at that high power. In fact the chip they're using to do the analog cancellation (QHX220) can only take 4 microwatts in at 2.4GHz before it is completely distorting. They probably want an IIP3 (a measure of dynamic range) of minimum 10mW to limit the distortion, which is fairly large for typical receiver hardware. It's not terribly hard to do with GaAs chips (but more expensive) and it will take some work to do it in CMOS/SiGe which is cheaper.

In other words they tested under very specific conditions, and currently there needs to be additional work done on the RF hardware end to make this viable in an actual product. Not that I'm criticizing them of course, their interest is exploring more the communication aspect. If a company wants to make a product of this all it takes is money to fix the RF dynamic range issue, they're not pushing the limits of possibility yet.

Reflections/multipath will reduce the actual isolation achieved by their antenna nulling technique, but they will still achieve some improvement in isolation as no reflections are 100% and there is two-way path loss involved. As long as they get enough isolation with the antenna nulling to keep the receiver front-end from saturating then they might be able to compensate for the multipath in the digital domain, depending on the processing power available. It would be pretty simple for it to do a self-calibration, though moving objects which reflect significantly would require more frequent cals.

GPS and CDMA use something completely different. Spread spectrum techniques like GPS and CDMA take a signal with (for example) 1MHz bandwidth and spread that data over a 100MHz bandwidth. Now up to 100 people employing this technique can transmit over that 100MHz bandwidth simultaneously, but there is no gain in throughput because it's the same in the end as those 100 users transmitting in a 1MHz bandwidth with user 1 at 1.000GHz, user 2 at 1.001GHz, and so on. The benefit of spread spectrum is that it's hard to segregate each radio into such a small bandwidth without interfering with adjacent users. It could not be used for full duplex single frequency radio because the transmitted signal would still swamp out the received signal, unless it were combined with isolation/nulling techniques like these Stanford guys are using.

The research page for the work in this article is here: http://sing.stanford.edu/fullduplex/
They are using multiple techniques to selectively null out the transmit signal at the receiver. Their main novelty is spatial nulling of the antenna. Two antennas transmitting the same signal will have points in space where the signals destructively interfere and cancel. If they are spaced by an odd number of half wavelengths then this includes the entire line between the two antennas, so this is where the receive antenna is placed. Then they use existing analog and digital techniques to further cancel out the component of the transmitter which appear at the receiver.

Although the techniques for this are well known the trick is getting it to actually work effectively, because you need to achieve very high isolation from your own transmitter to receiver in order to avoid the transmitter effectively jamming the receiver. Their antenna nulling is apparently what gave them that extra isolation they needed.

This PHD Comics issue is particularly appropriate here:
http://www.phdcomics.com/comics.php?f=878

While I have to applaud Google for trying to keep their users' accounts safe, I have to say that this idea is really untenable. Not everyone has a cellphone, not everyone with a phone carries it all of the time, and you might not always have reception. Just this last summer, I had a month-long internship in Nebraska. The town I stayed at had zero reception on Sprint's network and the nearest cell tower was over an hour away. And last February, I was in Switzerland, where again, I had no cell service.

Clearly then you are not well-suited to this optional extra feature, or at the very least you should not enable it while travelling abroad or in poorly developed areas. I for one think it's great that I now have the option to make my Gmail account far more secure.

Furthermore, if my bank can authenticate me without requiring an SMS, then certainly my email provider can do the same.

Does your bank even implement two-factor authentication? Mine doesn't. Of course it can easily and securely be done with RSA key fobs, but those are are fairly expensive and would require much more effort for Google to implement since they would need to snail mail you the key. It hardly makes sense for a free email account. Otherwise a phone call or text is one of the best ways to cheaply implement two-factor authentication.

A nice idea, but in addition to other criticisms presented in above comments this would not prevent a criminal from using pre-arranged codewords to communicate with outside affiliates. If I was a mob boss or drug kingpin I would probably take the time to work out such a system with my subordinates just in case, not sure if all criminals would go through the trouble of course.

When you've got a target as large as Apple you need to be smart about security.

Or you need to be William Tell.

And nothing stops you from using https://facebook.com/ [facebook.com] does it?

If you go to https://facebook.com/ you do view an encrypted home page. But all of the links to everything are just non-encrypted http. Unless you copy each link, paste it into the address bar, and prepend 'https://' to it (or write a browser script to do the same) then most of your facebook session will not be secured.

Water has a pretty high thermal mass so I don't think variable temperatures are anything to worry about

Sure water has a high thermal mass, but solar power irradiates the earth to the tune of ~1kW/m^2. That's why you can use a solar pool cover (essentially heavy duty bubble wrap - allows radiation in, limits convection out) to heat an 8 foot deep pool to over 105F on a hot summer day (in my experience). Most bio-reactors must have actively controlled temperatures to optimize production. The reality is it heavily depends on the volume to solar-incident surface area ratio they choose and the temperature sensitivity of the cyanobacteria they have engineered, details which will determine the presence/cost of cooling system.

Biocontamination can be dealt with fairly easily, by sequestration and redundancy.

This makes scaling much more difficult, since instead of increasing the size of each bioreactor you are instead proposing to build a lot of little ones, each of which must be separately monitored and maintained.

Waste product removal is a halfway interesting problem, but I'd bet Kevin Costner is working on it as we speak.

It's more than halfway interesting, it's a key factor in the viability of the system. If they can't remove the hydrocarbons and other waste products efficiently, then this scheme just won't work at all.

more of a political stunt, as it has always been the case with these "space missions".

Funding agencies are risk-averse. It may seem like a waste of time and money to conduct such a test, but now when the Russian space agency asks for money for a Mars mission from their government, they can point to this study as addressing one of the risk factors of this mission.

The government gave them the money to perform this study because the study itself is low-risk and will give them a much better idea how a large 6-person crew will perform under the simulated conditions.

It's all about taking small steps so that eventually mankind can take a giant leap.

Yeah, it's a trip to Mars - minus the lack of gravity, minus the cosmic radiation, minus the occasional pebble whizzing by at thousands of miles per hour, minus the constant knowledge that a few millimeters of metal alloy separates you from pretty much instant death at all times.

Surprisingly enough death isn't actually very quick in the vacuum of space (ref). You would maintain consciousness for about 15 seconds and be able to take actions which may save your life, and even after unconsciousness you would most likely survive without significant injury if returned to an atmospheric environment within about 90 seconds.

Apple effectively has 4 products. iPods, iPhones, iPads, and laptop/desktops.

You forgot about iTunes, which is estimated to have generated a revenue of $1.8 Billion in 2009. Sure the total revenue may not be as large as total hardware revenue, but it's not chump change either.

My big question is what is the payout rules? Do they deposit the money in my checking account automatically? Or do you have to have a minimum sales amount before they'll cut a check?

Having sold some textbooks through Amazon Marketplace they automatically transfer your funds every 14 days, and you can also have your funds transferred as fast as once per day. Here is how Amazon describes it.

This app marketplace might be run differently, but this is probably a good guideline for how they will disburse funds.

You're right, I apologize, all of my CNN money numbers are 1 year off because the numbers are posted in 2010 for 2009 by CNN money, and I didn't notice initially that they organize by posting year, not earning year.

I couldn't find a definitive number for Exxon's 2010 profit, but it looks like it is on track for about $26 billion profit. Much like previous years, still larger than Apple but at a lower profit margin.

Thinking longer term I don't think Apple's growth will reflect the growing markets of China and India, but Exxon Mobil will certainly continue to benefit from the increased oil consumption.