People sign up and never finish because the courses are downright awful. And there's no mind nor incentive for them to get better. Instructors think that just recording a lecture and putting it online is good education, but it isn't.

Watch Daphne Koller droning on about graphical models as the video shows her standing at a lectern talking, or showing a powerpoint-style frame while she reads the text on the frame to us.

Watch Anant Agarwal go through a *hugely* dense and boring derivation, only to stop before the end and say "but this derivation is too hard, there's an easier way". Twice. For the same result.

Try to figure out how many degrees of freedom a soccer ball has, then argue with Sebastian Thrun because the answer he thought you should have entered is not the mathematically correct one. (Also, see if you can figure out what this has to do with AI.)

For a breath of fresh air, watch Donald Sadoway take you through a delightful and satisfying explanation of chemistry. (Ignore the 1st lecture which is about class scheduling.) It's wonderful.

I could cite two dozen *major* problems with selected online courses - things that go counter to the fundamental goal of learning that would be obvious to someone familiar with human learning mechanisms or a testing group or even a member of Toastmasters. When I point these out to the chief scientist at edX, he responds with "we can't change the way we do things because of X".

Let me repeat that: the *chief scientist* at edX has no control over teaching techniques or video methods or course quality.

Some people (ie - Dr. Sadoway in the link above) have figured out how to do it right, but the vast majority aren't interested in quality. It's unfortunate that edX got all those millions in seed money, because we'll have to wait until they burn through it before they get hungry enough to worry about quality and effectiveness.

It's insane.

Third suggestion:

Fungi can be used to remove heavy metal contaminants in flowing water. Place a bunch of fungi mycelium in sandbags in the water stream and the fungi will filter out the contaminants as the water flows through. Come back later, remove the bags and replace with a fresh batch.

Contact Paul Stamets' group over at Fingi Perfecti and see what their experts have to say. They might even have a product you could buy for the purpose.

Here's a paper and some contact info to get you started:

http://www.sciencedirect.com/s...

http://www.fungi.com/about-pau...

First suggestion:

There's been a lot of interest in using Zeolites to absorb heavy metal contamination in water. One specific experiment involved dragging a bag of zeolites through ocean water, the zeolites absorbed enough Thorium to be industrially useful as an ore (if there were a demand for Thorium, which there isn't).

I've found papers that indicate that Zeolites will absorb copper and lead, two of the contaminants listed for the Mount Polley disaster; chances are likely that zeolites would absorb the other contaminants as well.

Here's two papers to get you started:

http://www.yourncdinfo.com/cli...

http://cnu.edu/arc/documents/p...

Second suggestion:

There's been some success in removing non-volatile organic pollutants from soil using steam injection. Essentially, sink a pipe into the soil, inject steam, cover the area with a tarp, and collect the steam/water as it percolates up through the soil. This method can be used to extract non-volatile organic components including tetra-ethyl-lead. (I found that last bit surprising, but this was directly confirmed to me by one of the scientists involved.)

Depending on the chemical nature of the contaminants (ie - solubility, polar/non-polar character &c) this might prove useful in decontaminating some of the mud slurry.

Here's a paper to get you started:

http://nepis.epa.gov/Adobe/PDF...

Before I get slammed by a P-Chem major, here's what's really going on with the entropy.

The reaction is exothermic, and this release of heat increases the entropy of the universe. At the same time, 4 atoms of source become 1 atom of product, so this aspect of the reaction *decreases* the entropy of the universe. (There's more ways that 4 atoms can be arranged in a box than there is to arrange 1 atom.)

At room temperature, the entropy increase from the release of heat is greater than the entropy decrease from the reduction in states, so the reaction is favored.

The entropy from the release of heat is inversely proportional to temperature. Double the [absolute] temperature and you halve the increase in entropy from the release of heat. With higher temperatures, the entropy increase from "release of heat" is smaller than the entropy decrease from "change of states", the total change of entropy is negative, and the reaction is no longer favored.

I wrote a simpler/shorter explanation to avoid losing sight of the main point.

Here's some background on the Bosch Haber process.

Whether a reaction will occur is based on whether energy is required and whether the reaction increases entropy. In the case of nitrogen+hydrogen => ammonia, the reaction is both exothermic and increases entropy at room temperature and pressure. If one could somehow ignite the process it would be self-sustaining.

The problem is, to ignite the reaction you first need to break N2 molecules into individual N atoms, and this requires a great deal of initial energy which is regained in subsequent steps. Something like 7eV per molecule to break them apart. The molecules in normal air have a bell-curve spread of energies, but very few of them reach energies this high: the reaction happens at room temperature, but very *very* slowly. A handful of molecules per second will react.

To get around this you can raise the temperature, increasing the probability that molecules will have enough energy to break apart. The entropy produced is inversely proportional to temperature, so when you start to have N2 molecules with enough energy to break apart, the reaction is no longer favored because it would result in an entropy decrease.

Since 4 moles of reactants result in 1 mole of product, increasing the pressure of the reactants will tend to favor the products, so you can use this to offset the deficit in entropy.

The Bosch-Haber process tries to find a "sweet spot" by increasing the temperature to get a reasonable number of N2 molecules to break apart, and high pressure to make the process favor the products.

At 200 ATM and 400 degrees, the yield is 15% (!).

Reaction vessels for this pressure and temperature are expensive, and the process requires multiple cycles of compression, decompression, removal of ammonia, and recompression. This takes a *lot* of energy and uses *very* expensive compressors which wear out over time and have to be replaced.

I haven't read the paywalled article yet, but if I'm understanding the abstract, they are breaking apart the nitrogen electrochemically. Just as running a current through molten NaCl will break it into atomic sodium and chlorine, running a current through nitrogen dissolved in KOH and NaOH breaks it apart and the reaction then proceeds at normal conditions. The reaction also supplies its own hydrogen by breaking apart water.

Much of the "green revolution" is due to the use of nitrate fertilizers, and the source material is finite: guano from Peru, for example.

If this process is as efficient as the abstract suggests and can be industrialized, it would be *huge*. It would give us an essentially infinite source of nitrogen-based fertilizer and reduce the worldwide consumption of energy by a couple of percent.

Coupled with a source of renewable energy, it would mean that the world could sustain its food production at current levels indefinitely.

This could be really, *really* big news.

This is an echo-chamber response: someone on the internet heard something, and keeps repeating it. It's rooted in emotional superiority, and comes from someone with no background in scientific research or statistics.

All attempts to pin obesity on the "that sounds about right" reasons have failed, including exercise and food intake - for both amounts and types of food.

In particular, lab animals grown today are fatter than the ones grown decades ago, despite having the same (and well-documented) diets and exercise. (Source.) Same with pets.

Current opinion holds that there is something in the environment that causes obesity - some agent that wasn't pervasive a couple of decades ago. Over 700 possible causes have been suggested, including your favorite bugaboo (whatever that is). We're slowly going through the options looking for the cause.

No diet will work, even that great "miracle cure" you heard about on Oprah. Lack of exercise doesn't cause it. Diets and exercise regimes work for *some* people because in changing their behaviour they eliminate the causal factor inadvertently - without knowing what it is. It wasn't the diet and it wasn't the exercise.

Try to keep current with scientific theory, otherwise we'll be repeating these old wives tales forever.

Can you explain to us exactly what AI is?

As a definition, the Turing test has problems - it assumes communication, it conflates intelligence with human intelligence, and humans aren't terribly good at distinguishing chatbots from other humans.

Also, using a test for a definition works well in mathematics, but not so much in the real world. Imagine defining a car as "anything 5 humans say is a car" and then trying to develop one. Without feedback or guidance, the developers have to trot every object in the universe in front of a jury, only to receive a yes/no answer to the question: "is this a car?"

Many AI texts have a 'kind of fuzzy, feel-good definition of AI that's useless for construction or distinguishing an AI program from a clockwork one. Definitions like "the study of programs that can think", or "programs that simulate intelligent behaviour" shift the burden of definition (of intelligence) onto the reader, or become circular.

One could define a car as "a body, frame, 4 wheels, seats, and an engine in this configuration", and note that each of these can be further defined: a wheel is a rim and a tire, a tire is a ring of steel-belted rubber with a stem valve, a stem valve is a rubber tube with a schrader valve, a schrader valve is a spring and some gaskets...

With a constructive definition, one could distinguish between a car and, say: a tractor, a snowmobile, a child's wagon, a semi, and so on. Furthermore, it would be conceptually straightforward to build one: you know where to start, and how to get further information if you are unsure.

Compare with a group from mathematics: a closed set plus an operator with certain features (associativity, identity, inverses), and each feature can be further defined (an identity element is...). Much of mathematics is this way: concepts constructed from simpler concepts with a list of requirements.

The study of AI seems to be founded in mathematics. At least, all the AI papers I've read are heavy with mathematical notation - usually obscure and very dense mathematical notation. It should be possible to determine with some rigor what the papers are talking about.

Can you tell us what that is? What *exactly* is AI?

The problem with the petition is that it has no consequences.

Would it help if petitioners agreed to vote *against* the incumbent president's party at the next election if the issue isn't addressed?

Some of the petitions net upwards of a quarter-million signatures. Is that enough votes to get Washington to take notice?

There is an argument to be made that Jesus was intentionally trying to make a martyr out of himself. He failed to put up a defense when asked.

Your statement fairly reeks of the innuendo "this isn't something to get angry over, because he wasn't normal".

It dulls the impact of an important event, it's unfalsifiable (you cite no evidence, just "there's an argument to make"), and it serves to quell any discontent over the current political situation.

I like it. Can the technique be reversed in future incidents? Can a properly crafted response be used to whip up political discontent and restlessness?

I wonder...

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Go to AltSlashdot.org if interested

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Contact me if interested

John (at) AltSlashdot (dot) org

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Contact me if interested

John (at) AltSlashdot (dot) org

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Contact me if interested

John (at) AltSlashdot (dot) org

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Contact me if interested

John (at) AltSlashdot (dot) org

I've registered "AltSlashdot.org".

I intend to run a site much like Slashdot used to be - better articles, less decoration and less "in your face" functionality. I'm reviewing and getting comfortable with slashcode right now. I'm looking for volunteers to help with setup and running the site.

If the site becomes profitable, I intend to hire from the pool of volunteers. If you've ever wanted to participate in a site like Slashdot, here's your chance!

I'm particularly in need of people who can:

• Set up and manage a high-traffic site (servers, load-balancers, data sites, &c)
• Edit story submissions
• HTML, CSS, and script creation/bugfix/repair

Contact me if interested

John (at) AltSlashdot (dot) org