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Member since: Fri Sep 9, 2005, 07:39 PM
Number of posts: 25,414
Member since: Fri Sep 9, 2005, 07:39 PM
Number of posts: 25,414
ironically, one of the signs I was having problems (though I didn't realize it at the time) came when I went to see an old 50's 3D movie. I had to watch the movie for a long time -- say half an hour? -- before the 3D effect worked for me. That was a sign my binocular vision was failing, but I didn't realize it.
The main therapy consisted of viewing red/green or polarized anaglyphs (trademarked as Tranaglyphs ™), while the therapist adjusted the separation between them. Since my left eye was turning outward, at first I could only fuse the two images when they were widely separated. With repeated exercises, over several weeks, I was finally able to fuse the images at normal separation. After each session, I could tell that my vision was taking on a little added depth -- and an hour or two later I would get a real hammer-between-the-eyes headache. After the whole therapy sequence was finished, it still took some time to re-adapt to full binocular vision, and my eyes tended to tire easily.
A big prerequisite to successful therapy, in my case, was having my lens prescription reduced by a doctor who was very careful not to over-prescribe the lens strength. Many ophthalmologists tend to over prescribe, and if you are young and nearsighted, your eyes will adapt to the overcorrection. Over a period of many years, I had accumulated quite a lot of overcorrection in one eye, causing that eye to suffer so much fatigue that it would stop focusing properly and my brain would simply suppress the image from that eye. It was a real shock to discover one day that I could cover my left eye and leave my vision almost unaffected -- the image from that eye was not being processed much at all. Some doctors routinely check for overcorrection, others -- not so much.
Sue Barry's book describes some of the other treatments used. She had been stereoblind her whole life, unlike me, so her doctor started her off with more basic therapy than I needed. I thought the bead-on-two-strings would have been a good home exercise for me, but I didn't learn about it until after I no longer needed therapy.
Surprisingly, it is not ophthalmologists, but optometrists who are the leaders in diagnosing and treating problems with stereovision, especially in children. See http://www.covd.org and http://optometrists.org/public_eye_care.html
Posted by eppur_se_muova | Fri Jul 20, 2012, 01:48 PM (1 replies)
Posted by eppur_se_muova | Fri Jun 8, 2012, 02:38 AM (0 replies)
A Greek king and a Persian king got into an argument over man's "natural" language. The Greek king insisted that it was Greek, of course, and the Persian king insisted that it was Persian. So they proposed an experiment -- the kind that only kings could get away with. They took a newborn baby boy from its mother and carried him off to be raised by a hermit high in the hills, far away from any other people. The hermit -- who was a deaf-mute -- provided the baby with goat's milk and raised him to the age of twelve. At that time, the two kings stopped by to see how their experiment had turned out. When they knocked at the door of the hermit's cabin, the boy answered the door. The two kings silently glanced at each other, and then nervously waited for the boy to speak. Finally, the boy opend his mouth and gave voice to: Baaaaaaaah!
(This is a fun joke to tell, if you can do a convincing goat bleat. )
Posted by eppur_se_muova | Wed Mar 28, 2012, 05:24 PM (1 replies)
There is no direct conversion of graphite to carbon fibre which is practical on a large scale, though graphite "whiskers" can be produced this way on a very small scale -- more of a laboratory technique than a process suitable for production.
Carbon "nanofibres" can be grown from hydrocarbon precursors such as methane, and methane can be made from CO2 and H2. So if the H2 is "green", you've got a way to convert CO2 to CH4 to carbon fibre, but the conversion will be many, many times slower than the production of CO2, and consume quite a bit of energy as well.
Currently, carbon fiber is made mostly by pyrolysis (high-temperature decomposition) of carbon-containing precursors such as polyacrylonitrile. Acrylonitrile is made from propene, ammonia, and oxygen, with propene coming mostly form petroleum, so either one needs to find a competing process, or find a way to convert CO2 to propene. Some propene has been made from methanol, but I don't have details of this (it's probably safe to assume it's the methanol-to-gasoline process invented by Mobil a few decades ago) -- presumably a mixture of products is formed.
It's quite conceivable one could obtain propene from agricultural byproducts (which are just captured CO2) such as acetone (obtained by starch fermentation); but currently it is cheaper to go the other direction, and make acetone from propene, because of the artificially low cost of heavily-subsidised petroleum.
IF we can recover the CO2 economically, and IF we can obtain enough H2 in a renewable and economically competitive fashion, then CO, methane and methanol derived from CO2 will become just another stream of simple precursors to feed into the process streams built around inputs of coal, natural gas, and petroleum. The problem at this point is that the deck is stacked in favor of petroleum-based inputs.
Bear in mind that only a few percent of petroleum goes to make materials -- the majority is burned as fuel. So even industrial-scale conversion of CO2 to materials would only offset a tiny part of CO2 production from burning fossil fuels. Probably it would be better to convert CO2 into fuels such as methanol or dimethyl ether, which would at least form a closed carbon cycle when burned, without the need to bring more fossil carbon to the surface.
Also, if you're thinking of building "big stuff", keep in mind that carbon fiber is combustible -- you might want to think twice before using it in buildings, bridges, etc. in place of non-flammable steel and concrete.
Posted by eppur_se_muova | Mon Feb 20, 2012, 08:28 PM (1 replies)
It's very unlikely that any particular fossil organism is our direct ancestor, even if it's from the right phylum, class, order etc. The best we can say is that it's from a genetic population that's very close, *possibly* identical, to the one that led to us.
("If we evolved from monkeys, why are there still monkeys?" is the question to which this is the answer. We evolved from particular populations of primates, none of which exists today, but some of which split from the ancestors of surviving primate populations. The more recent the split, the more similar our genomes to those surviving primates. But none will have a genome identical to our direct ancestors -- those genomes evolved into us, or into other well-adapted, hence relatively long-surviving, primate populations.)
Posted by eppur_se_muova | Thu Feb 9, 2012, 02:25 PM (2 replies)
A pox on the fools who got the "synthetic" label established. This is not a synthetic version of a natural product, or a modified natural product. It is (one or more) totally synthetic "analogues" which bind to the same receptors (more or less) as THC but in significantly different fashion. The perceived effects are somewhat similar to MJ but the differences are more significant than the similarities.
The active ingredients are *NOT* those found in natural MJ, and some of them are much more pharmacologically active. These compounds have found a market in an effort to circumvent anti-MJ laws, but they appear to be immensely more dangerous than MJ itself. It would be much safer to legalize MJ than to try to block the market in cannabis imitators. Cannabis imitators have sent a number of people to emergency rooms and one is clearly implicated in at least one death. Given the short period of time these drugs have been available, and the smaller number of users compared to MJ, they are clearly the sort of public danger that opponents of MJ always wanted MJ to be.
Posted by eppur_se_muova | Sun Jan 29, 2012, 10:00 AM (1 replies)
#1 in Books > Politics & Social Sciences > Government > Civics
#1 in Books > Politics & Social Sciences > Current Events > Civil Rights & Liberties
#15 in Books > Politics & Social Sciences > Politics
Does Gingrich have a secret stake in the publisher ? He's done more to get people to read Alinsky than anyone else in the last 30 years.
Hardball did a spot on Alinsky's "Thirteen Rules", and it's obvious that Gingrich is using many of them. NG is obviously pissed that someone else came up with these "Big Ideas" first. But I'll bet his really big gripe is that SA helped blacks in their organizing efforts.
The Wiki on SA is worth reading. He avoided joining political organizations, and is generally regarded as a "leader of the nonsocialist left". Here's a prescient -- and worrying -- excerpt:
Alinsky described his plans in 1972 to begin to organize the white middle class across America, and the necessity of that project. He believed that what President Richard Nixon and Vice-President Spiro Agnew called "The Silent Majority" was living in frustration and despair, worried about their future, and ripe for a turn to radical social change, to become politically-active citizens. He feared the middle class could be driven to a right-wing viewpoint, "making them ripe for the plucking by some guy on horseback promising a return to the vanished verities of yesterday." His stated motive: "I love this goddamn country, and we're going to take it back."
Posted by eppur_se_muova | Fri Jan 27, 2012, 07:38 PM (1 replies)
Imagine a school where a student could sketch out an idea for a new design of bicycle and not only draw it in 3D using a computer-aided design package but actually create a scale-model and test it out, using inexpensive materials and a special printer that they can build themselves in the classroom.
That's the vision put forward by Ben O'Steen, a software engineer with a social conscience who is thinking about the implications of a world where 3D printers are no longer just expensive prototyping systems for large companies but have fallen into the hands of the masses.
He has been inspired by the RepRap, a desktop 3D printer capable of printing plastic parts by extruding a heated thermoplastic polymer under computer control, which then sets as it cools and makes a usable object.
The RepRap project was started in 2005 by Adrian Bowyer, who teaches mechanical engineering at Bath University.
The schematics and all aspects are freely licensed for anyone to implement or adapt, and the current version, called "Mendel", can be built for around £350.
It makes objects from a cheap plastic made from corn starch, so is well within school budgets.
Posted by eppur_se_muova | Sat Jan 21, 2012, 05:21 AM (18 replies)
not to mention deaths due to overloaded coal trucks:
From 2000 to 2004, there were more than seven hundred accidents involving coal trucks in Kentucky alone; fifty-three people died, and more than five hundred were injured.
(notice the trucks in the video driving over bridges w/10-12 ton limits)
Posted by eppur_se_muova | Thu Dec 22, 2011, 01:11 AM (0 replies)
Power going to my head in 3 ... 2 ...
Seriously, not much is going to change. I would like to suggest importing the SOP from the DU2 Science Forum -- it is a bit more emphatic about what constitutes acceptable "science-related discussion" and what is not. Not that there is any need to split hairs, or impose rigid guidelines -- I just see it as more detailed, and I would hope, clearer. I think the admins may have deliberately cut the length of the SOPs in the belief that smaller is better. I do find the original SOP not just more emphatic in discouraging pseudoscience, but also more welcoming to non-specialists.
This forum is for the discussion of science. Please feel free to post any news about science from scientific journals (Nature, Science, Cell, etc.) or from the mainstream media (The New York Times, AP, BBC, Wired, etc.). Also, feel free to post your own questions, comments, or other topics about science.
This forum is open to a everyone with an interest in science. Whether you're a tenured professor with a PhD in physics, or an interested lay person who occasionally watches science documentaries on the Discovery Channel, you are welcome here.
Threads about topics that are not science are not welcome here. Please do not post threads about pseudoscience (astrology, homeopathy, crop circles, bigfoot, alien abductions, and the like), which is not science. Don't even post threads bashing pseudoscience, because most people here in the science forum don't need to be convinced, but more importantly because such topics are bait for people to come here and argue the opposing viewpoint -- and then all hell breaks loose. If you want to discuss pseudoscience there are plenty of other places on DU where you can do so. (Visit the Skepticism, Science and Pseudoscience Group for discussions from the skeptics-only perspective. Visit the Astrology, Spirituality & Alternative Healing Group for discussions from the mystics-only perspective.)
Questions and comments from non-experts are welcome. You need not hold a consistent scientific worldview in order to participate here, but visitors are expected to have a genuine interest and appreciation for science. We reserve the right to bar anyone from posting here who is trying to deliberately stir up trouble or push some sort of personal agenda.
Science tends to be a pretty quiet and mostly noncontroversial group. Maybe once every month or so (or even less) there's an attempt to post what is commonly referred to as 'woo' (is that just a DU thing?) -- that is, pseudoscience, or speculation gussied up as science. That's pretty much the only time you're likely to hear from me wearing my Host hat.
I would like to invite a few people to be co-hosts -- not too many, given what a well-behaved, quiet little group this is ordinarily. I have already heard from a couple of people and welcome any PMs or replies to this thread from others who are interested. If you happen to have a special interest/field of expertise I would be interested in knowing what it is.
Posted by eppur_se_muova | Thu Dec 15, 2011, 10:20 PM (16 replies)