Follow Slashdot stories on Twitter


Forgot your password?

Comment Re:Actually, you CAN'T do that (Score 1) 65 65

The Everettian interpretation is certainly better than the Copenhagen interpretation, since it doesn't raise the measurement problem; however, it's no where near as simple (in the Occam's razor sort of way) as the Bohmian interpretation.

However, I think the history of physics should teach us that different interpretations are often different facets of the same thing. Compare Lagrangian and Hamiltonian mechanics, for example. They are both accurate (at least for our universe), but quite different in their approach and interpretation. However, they are unified in that they are dependent on conservation laws. A unified theory should be approachable from both directions, and possibly other directions as well. It also turns out that one is often easier to apply than the other in certain situations, and thus both approaches are useful.

Perhaps there is a bit of truth in each of the QM interpretations.

Comment Re:Too Far Away (Score 1) 133 133

The problem with trying to detect radio signals from hypothetical alien civilizations is that they would almost certainly have to be intentionally signaling us, and at great expense (it would take a lot of power). High power analog TV transmissions (the type that can be distinguished from background noise) are nearly extinct on earth, and certainly won't last through the century.

As efficiency improves, every from of communication becomes more and more indistinguishable from random noise to any outside observer that doesn't know the protocol. So, unless we catch a civilization in the particular period of time between the invention of radio, and the invention and perfection of efficient communication, we won't be able to actually detect their signals to each other. I guess we could just look for unusually high powers of random noise, but there are already so many potential sources of high-power random noise that it seems pointless.

Comment Re: Too Far Away (Score 1) 133 133

I'm not so sure thats true. I used to think something similar; however, I'm now convinced that we're really living in the most dangerous time period for our race right now. The difficulty is that in the next ~100 years (order of magnitude estimate) is that we need to transition from a growth economy to a steady-state economy, and the growing pains might be too much for us.

I think if we can get through this next ~100 years, then it will be trivial to get through the following 10,000 or more. Eventually we'll have to get off this rock to survive true global extinction events, but those should be quite rare at this stage in our solar system's life.

Comment Re:HORNET vs Tor (Score 1) 59 59

I know nothing about the TOR protocol, but could you use a random number of hops drawn from a modified Poisson distribution in which the user can modify the minimum number of hops? Every time a layer is peeled off, the node would essentially check that this isn't the last hop, and behave accordingly.

Comment Re:"[T]raders have to react so quickly" -- really? (Score 1) 92 92

Wouldn't that make it a positive sum game?

Unless you include the natural capital (resources) in the system, in which case it's a zero sum game. Of course then you should also include the influx of energy from the Sun, which again makes it a positive sum game.

Comment Re:lettice under LED grow lights? (Score 1) 279 279

GaN-based LED's have only been commercially available since 1994, and only recently at a reasonable efficiency and price. Using LED's is quite different from using tungsten filament or gas discharge lamps (aka flourescent lamps).

As mentioned previously in these comments, plants only absorb a small fraction of the solar irradiation. For example, chlorophyll, the dye molecule used by many plants, only absorbs significantly in relatively narrow bands of the blue and red, corresponding to 2% of the total solar irradiant power.

It turns out that the bandwidth of these absorption peaks matches quite closely with the bandwidths of blue and red LED's operating near room temperature. Thus, even with 20% efficient LEDs the total power-to-plant-product efficiency can likely approach 100%. If you replace the plants with standard 18% efficient solar cells, you could feasibly have several layers of plants powered by the same footprint, although at a greatly increased capital cost.

If you add in the improved control over germination and growth afforded by an enclosed and highly-regulated environment, the economics might begin to make sense, especially considering the long lifetime of color-pure LED's (much longer than phosphor-converted LED's).

Comment Re:I do not think they qualified as 'organic' (Score 1) 279 279

Almost all of the pictures look like purple + red to me. There's one picture that looks like it has a fraction of white lights. However, most LED white lights are actually blue/uv + yellow.

Thus, you seem to be jumping to conclusions. If anything, you're point about plants only being able to use 1% of the power from sunlight suggests that they might be on to something.

Comment Re:So does this qualify as 'organic'? (Score 1) 279 279

Parent deserves to be modded up.

What ultimately matters here is economics. There is obviously a huge capital cost involved here, but it very well may be merited, especially for growing delicate species. And the more these systems are utilized, the more economy of scale will make it economical for more general applications.

I am a bit put off by the lack of costs in the article, but I guess that is to be expected from a press release. Since this is still in research stages, it is almost certainly not yet economical. However, if it is even within a factor of 10x of breakeven over a ~20 year time frame (including capital costs, but replacing the researchers' salaries with technicians'), then this could be a significant player in the future.

"There is such a fine line between genius and stupidity." - David St. Hubbins, "Spinal Tap"