joema

Your sensory input is physically stored in your brain as memories. We don't yet understand the exact bimolecular storage mechanism, but it's obviously of a physical nature -- damaging the physical brain or affecting it with physical drugs causes biological changes that affect memory. This would require a relatively complete understanding of the physical storage mechanism, which we don't yet have. Therefore not "discovering" memories in the brain is simply stating the current limited knowledge level. It doesn't mean that will never be discovered. In 1950 we hadn't discovered what was on the surface of Venus, but that didn't mean it would never be discovered. Memories are obviously stored in the brain -- where else would they be? When ailments occur that affect the physical brain (Alzheimer's, etc), this affects memory. When you take substances that affect the physical brain (caffeine, etc) this affects memory. There are many theories of memory storage, just as there are many theories of cosmology. Continued research and experimental evidence will determine which are ultimately most correct. While the popular press often uses the simplification of the brain as a computer, and memory as data, researchers understand the brain is different. However you can obviously fit abstract items such as musician's memory into physical storage. Just because we emotionally perceive a holistic and spatial aspect to this doesn't mean it is, or that it can't be physically stored. E.g, not long ago many people felt a computer could never beat the world's best chess player. The same reasoning was invoked -- humans think holistically in complicated strategies, etc. People considered their complex feelings and thought processes when playing chess, and reasoned a computer could not possibly reproduce those. Yet a computer has now beat the world's best human. So what if it uses brute force or different underlying machinery -- the final result is what counts. Likewise there's no reason to doubt a sufficiently advanced computer could store complex items like musician's memory. We can easily conceive our possible memory capacity -- we simply can't yet verify these conceptions. The original post starting this thread just asked can memory size be measured, hence it's appropriate to discuss what is known about that. The physical brain obviously stores your memories, otherwise you wouldn't be having them. Your memory is obviously affected by physical brain changes such as disease, drugs, etc, showing the storage is physical in nature. We don't yet know the exact storage mechanism, but that doesn't mean no such mechanism exists. E.g, we don't yet know the physical mechanism of inherited lower animal "instinct", but it obviously exists -- ants dig tunnels without being taught, and this knowledge is somehow physically encoded into a single cell at conception. Nobody is definitively saying synapses measure how many memories can be stored. The brain obviously has far greater memory capacity than the number of synapses. Yet synapses may be somehow related to memory capacity, and some theories discuss that possibility.

IOW = In Other Words. Yes, immediately after posting I added the last paragraph. If there's more than a 1-2 minute gap, I usually write "edit/add" before the addition, but if it's immediate I don't do that. The forum software indicates at the bottom when and whether the message has been edited. That's an excellent point and I agree. Regarding the genetic basis for inherited behavior in lower life forms, upon further reflection it seems almost certain genetically based, at least in some cases. Why? Even an ant starts as a single fertilized egg. At that moment it consists only of a single cell. In some cases you can remove that cell and grow it in a lab. Yet the resultant fully developed ant knows how to dig tunnels, how to walk, etc, and no other ant teaches it. Somehow, somewhere in that single fertilized cell all those behaviors are encoded. Where else besides the genetic material could that be stored? The cytoplasm? Transmitted via ESP from the parents? Anything is possible but genetic encoding seems the most likely.

You may be narrowly correct, but I haven't checked the latest literature. There is no doubt lower life forms inherit biologically pre-coded highly specific behaviors. Whether the location of the pre-coded information is gene-expressed proteins or something else, we don't know. However from the standpoint of this discussion, it makes little difference other than semantically. IOW whether you inherited a specific behavior via a genetic pathway or some other bimolecular pathway, the end result and associated controversy is the same -- inherited biologic influence on behavior, and what degree of individual responsibility ensues. Just from deduction there's a good chance lower life form "instinctive" behavior is genetically based, whether directly or indirectly. Genes determine the form and structure (even on a minute level) of the developing organism. Regardless of the exact details of the biomolecular pathway, it seems very likely genes are involved somehow, else how would the behavioral data be passed down? Where else would it be stored during the earliest part of gestation?

Environmental factors can trigger the inherited genetic weakness that causes schizophrenia. This doesn't mean environmental factors cause 50% of the symptoms, merely that statistically roughly 50% of identical twins, on average, will develop the condition if their twin does. It's similar to certain types of cancer which have a clear genetic component. E.g, women with the BRCA gene mutation have a 33% lifetime chance of breast cancer, vs 12.5% for the background population. This doesn't mean that environment has 67% of the influence in whether the cancer happens in BRCA cases. If you took 100 women with the BRCA mutation, put them to sleep and fed them intravenously for years, despite identical environments a higher than normal percentage would still develop the disease. Whether schizophrenia, Tourette Syndrome, or cancer, once the condition happens, you've got it. Environment may play a role in whether it happens, but once it happens genetics greatly determine development and progression. With behavioral aspects the situation is more complex. You generally can't attribute complex actions like murder solely to genetics. There may be rare exceptions, say a hallucinating schizophrenic, but generally we consider people responsible for their actions. However this may not be totally correct. E.g, your mood and emotional state are affected by substances like alcohol, caffeine, or illicit drugs. Consider someone having 8 cups of coffee then yelling at their co-worker. Or someone having 6 drinks at an office party and insulting their manager. After having consumed those substances, should they have simply mustered the self control to guard their behavior? After consumption, to what degree is their behavior determined by their conscious control vs what degree by the substances they took? Most people would agree it's a combination of both. Just as a person's mood and behavior can be influenced by external substances, with some people mood and behavior is similarly influenced by internal biochemical or genetic factors. Some people may be born with an inherited genetic temperament similar to the person who drank 8 cups of coffee. Does that mean he's not responsible for his actions and can blame his genes? No, but we also cannot say his genes have no impact on his behavior.

In general I don't think any reputable scientist says genes are uniquely responsible for specific human actions. However there may be uncommon narrow exceptions (see below). Genes can INFLUENCE certain behaviors. This is obvious from studying identical twins who are separated and raised in different environments. Such identical twins have identical genes but their family, nutritional, and educational environments are totally different. There's apparently significant genetic influence of varying amounts across many areas. The degree of influence varies depending on the specific item. E.g, if one twin develops schizophrenia, there's about a 50% chance the other will, which is vastly higher than background probability. Outcome isn't predestined and environmental triggers play a part, but genetic influence is dramatic and inarguable. It also appears there's significant genetic influence on temperament, aptitudes, intellect, etc, but the degree varies. I don't know what the current literature says for these. So you can't generally blame solely your genes for specific behaviors. However there are possible exceptions to this. E.g, if you heard someone in a restaurant start loudly cursing, you'd attribute this to "behavior" (which he's responsible for), not genetics. However maybe he has Tourette Syndrome, a likely genetic problem that can cause such behavior. http://en.wikipedia.org/wiki/Tourette_Syndrome In animals (esp. lower animals) it's obvious there's a genetic basis for specific behaviors. E.g, nobody teaches ants how to build tunnels. But what we loosely call "instinct" is actually genetic behavior encoding. How that works is one of the greatest mysteries in biology. Figure it out and you'll unquestionably win a Nobel prize.

In general the opposite happens -- antidepressant meds decrease anxiety and suicide rates. You're probably thinking of a few sensational cases publicized by the media where a depressed person taking an antidepressant committed suicide. This is obviously difficult to evaluate, since depressed people commit suicide more than the average population, even if NOT on medication. A number of people die from taking aspirin each year, but overall the drug has a beneficial effect.

This has been known a long time. It's obvious neurotransmitter levels are not in themselves the cause of clinical depression, because it only takes 1 hr for increased neurotransmitter levels to occur after taking an antidepressant, yet weeks are required for the therapeutic effect. Something about changing neurotransmitter levels initiates a chain reaction, which downstream results in some neurobiological change that is actually responsible for the therapeutic effect. What is this? Figure it out and you'll probably win a Nobel prize, and that's no joke. Ronald Duman at Yale is doing some interesting work in this area. His idea is the neurotransmitter changes ultimately causes increased BDNF (Brain-Derived Neurotrophic Factor), which over several weeks causes increased growth in neuronal dendritic spines. The improved neuron pathways is the ultimate corrective action. By this theory, the upregulation in BDNF is the "final common path" by which most antidepressants work, regardless of whether they initially manipulate serotonin, norepinephrine or dopamine. This theory explains the time lag problem from AD administration to symptom relief, and why altering different neurotransmitters can all alleviate depression. Tentative results even indicate ECT also ultimately causes increased BDNF, so most pharmaceutical antidepressants may funnel into this one neurobiological mechanism. If you're a medical professional, you can look at his research papers. Here's a good popular-level article on this and related areas: http://www.psychologytoday.com/articles/pto-19990301-000031.html

That's exactly right. You can't tell, therefore clinicians must be prepared to treat either component. Constraints about only treating one or the other means addressing the problem with half your tools missing.

Actually what was once called "battle fatigue" is now understood to often be latent mental health disorders triggered by stress. This is obvious since many soldiers undergo the exact same environment, yet only some develop it. That is how depression and some other mental disorders work. There's a latent problem that surfaces only under stress. The stress could be any kind of emotional trauma -- family abuse, divorce, or battlefield stress. There is unquestionably a major biological component to many mental health disorders. This is proven beyond a doubt by studies of identical twins who are raised apart. We daily accept chemically-induced modification of mood and emotions. Anybody who has consumed caffeinated coffee or alcohol can attest to that. Just as those external chemicals can influence your mood and emotions, with some people internal biochemical factors can. Some tend to view brains as identically prepared race cars, where drivers have 100% of the responsibility for winning or losing. If he loses you blame him -- he has the same car everyone else does. However it turns out our brains are not like identically prepared cars, or computers. They are each biochemically very different, and some people have significant neurobiological problems that affect mood and emotion. This can have a profound influence on them, just like a heavy dose of alcohol or caffeine can affect a person. That doesn't mean there's no place for talk therapies. Through emotional trauma or poor coping skills a person could develop serious problems requiring professional psychiatric help. However without acknowledging the often biological component of mental health disorders, you're possibly only treating part of the problem.

You're right, I neglected the compound consumption of coal. Actually according to BP there are only 192 years of coal left worldwide at current global consumption levels. However coal consumption is increasing at 2.5% per year. I don't know the formula for compound spending of a fixed amount, but there's probably less than 80 years left considering the annual consumption increase. Numerous sources indicate oil shale and tar sands will be economically competitive with conventional petroleum prices of roughly $70 per barrel. Within a decade conventional oil will top $70/bbl permanently. Yes the environmental cost of mining oil shale and tar sands is huge. But so is the environmental cost of burning billions of gallons of gasoline and trillions of tons of coal per year, and we're doing that right now. On average, Europe consumes about as much total energy AND oil per GDP as the US. That's despite all the supposed advantages of density, mass transit, etc. See attached PDF. The US consumes a bigger total figure because the economy is so big. It's true urban sprawl is wasteful, but it has already happened. You can't go back in time and prevent it. To rearchitect the fabric of society would take many decades. Long before you were finished, we'd be out of oil, and maybe out of coal. Even if magically overnight you could change the US to be like Europe from an urban planning standpoint, it's unclear that would yield the needed energy savings. It's not doing so in Europe right now. As mentioned previously, even if all cars on earth vanished, it wouldn't vastly change the energy picture. Conventional oil would still run out fairly soon. And transportation energy use is mostly unrelated to coal consumption, which (as you mentioned) will run out sooner than we think. Maybe 80 years. IMO the long term energy problem is so bad, trying to restructure the urban and transportation landscape is too little, too late. By the time you accomplished anything substantive, conventional oil will be gone. And if Europe is any example, doing so wouldn't save much energy. Yes, agreed, but getting rid of the cars won't help the energy problem sufficiently to make it worth while. The math is very simple: all cars only consume 37% of world oil. Plus even extreme measures wouldn't get rid of them all, just reduce that number. With a dictatorial world government you could probably reduce oil consumption to 15-20% of the total, which just isn't good enough. If it weren't for the huge non-conventional oil sources, he'd be right. It would be apocalyptic. But since there are 5 trillion barrels of non-conventional oil, that will simply be mined and burned, of course at a major environmental cost. We'll probably pay double the price per gallon, but it won't run out, nor will modern society vanish. Is that the best path? No, but it's likely what will happen. Plus it's very unlikely even draconian measures unknown to democratic society would make a major difference. At this late stage, the problem isn't politics, it's physics and mathematics. It's like trying to stop a locomotive within a hundred meters. You either begin the effort several km away, or it's too late. 04ecsummit-brown.pdf

Non-conventional oil will have to be used. As shown in my previous post, it's too late to try and conserve conventional oil. Nothing meaningful can be done that substantially delays peak oil or ultimate exhaustion of conventional resources. Dedicating gigantic land tracts to growing energy crops is useless, as it's the achievable yield makes it impossible to provide a major percentage of transportation energy. So you're right, why do this. 50g/m^2/d have been achieved in practice, not just inside a lab. Yes further research is needed about how to maintain this long term. Yes there are issues to resolve in this area. While biodiesel vehicles would emit CO2, it would still be a huge net decrease, because you're only emitting the power plant CO2, not power plant plus current petroleum vehicle CO2. You're only recycling what the power plants are already emitting and you're eliminating the CO2 from petroleum vehicles. According to the UNH research alcohol constitutes only 10% of biodiesel volume. Yes, that's still a lot. Currently the US already produces 3.4 billion gallons of ethanol per year, and a bill was just approved to mandate 8 billion gallons per year by 2012. US gasoline consumption is about 131 billion gallons per year. So from a volume standpoint, that's 6.1% of gasoline production. Accounting for ethanol's lower energy content, it's 4.1% of current gasoline energy consumption. So it doesn't seem totally impossible to provide the needed ethanol. http://www.ksgrains.com/ethanol/useth.html http://feinstein.senate.gov/05releases/r-ethanol-amndt.htm I'm not saying biodiesel from algae is guaranteed to work (i.e, provide a significant fraction of transportation energy). However I am saying that all other biomass approaches are guaranteed to NOT work, just from an yield/acreage standpoint. At least biodiesel is theoretically capable of the needed yields, which the others are not. http://www.unh.edu/p2/biodiesel/article_alge.html http://www.biodieselamerica.org/node/1086 http://www.nrel.gov/docs/legosti/fy98/24190.pdf (large PDF) http://www.unh.edu/p2/biodiesel/pdf/algae_salton_sea.pdf http://www.osti.gov/fcvt/deer2002/eberhardt.pdf

If every car (and truck) on earth vanished, peak (conventional) oil would still happen, just delayed a couple of decades. Worldwide, road vehicles only constitute 37% of oil consumption. Since non-transportation oil consumption increases at about 1.2% per year, in 38 years we'd be consuming just as much as before all the cars vanished. Also during that period, we'd STILL be consuming petroleum at fantastic rates, just somewhat less than before. Oil field peak production capacity would be declining during that period as the remaining supply is sucked dry. There are about 1.1 trillion barrels of conventional oil left, and the world currently consumes 30 billion barrels per year. Even if NO peak happened -- if every oil field could produce at infinite rates -- the supply would be totally exhausted in about 28 years. Getting rid of every car and truck on earth would only extend this to 46 years (accounting for typical annual consumption increase for transportation and non-transportation sectors). So regardless of when we hit peak oil, the conventional oil supply is very finite and will soon be exhausted, regardless of whether cars exist or not. http://tonto.eia.doe.gov/FTPROOT/international/edexfiles/mary.ppt From a supply standpoint, utility energy is very different from transportation energy. There's enough coal to last for hundreds of years. Oil will be mostly depleted in a few decades, and peak oil will happen much sooner. As shown above, it wouldn't matter if Ralph Nader was appointed absolute dictator of the entire earth. Even if every car was destroyed overnight, world oil consumption is so high and the supply so limited (even for non-transport usage), it will soon be nearly exhausted. Even if all cars disappeared and everybody traveled on magic carpets, the limited conventional world oil supply will soon be almost exhausted. Long before then the oil will mostly be gone. Spending resources restructuring all of society would be better spent solving the transportation energy supply problem.

I meant most utility generation today is hydrocarbon fuels. Whether it's natural gas, coal or petroleum, it's still hydrocarbons. Of course from a supply standpoint there's plenty of coal for a long time. Yes BEVs can be used much more widely, in fact the US national average commute distance is about 10 mi, so you don't even need new battery technologies for that. However if used in very large numbers they'd require new utility generation capacity. But I doubt anybody wants 700 new coal (or nuclear) plants. In fact most people don't wany any new plants, they just want energy, which of course is impossible without new plants. Yes new technology nuclear plants such as the Integral Fast Reactor can theoretically solve (1) energy supply problem (2) plutonium proliferation problem, (3) reactor safety problem, and (4) most of the radioactive waste problem. http://en.wikipedia.org/wiki/Integral_fast_reactor However it seems unlikely they'll ever be built, and certainly not a huge numbers required to supplant hydrocarbon fuels or power a nation of BEVs. My guess is we'll keep burning oil in internal combusion vehicles until oil permanently goes over $70-$80 per barrel. Then nonconventional oil sources (tar sands, oil shale) will be developed, and we'll just keep burning that. We (in the US) will probably pay $3-$5 per gallon, but some people pay that today. Environmental impact will be bad, but at least oil won't run out.

If you mean hydrogen/fuel cell vehicles, I don't see how that could work on a huge scale, because unlike petroleum hydrogen isn't an energy source -- it costs energy to make hydrogen. World transportation energy consumption is about 100 quadrillion BTUs (2.93E16 watt hours) per year. To provide that (or a large fraction) from most alternative sources is essentially impossible. Biodiesel from algae is at least mathematically capable of it. Corn ethanol or biodiesel from other sources is not, nor is solar/hydrogen or wind/hydrogen. Many alternative sources and technologies work fine on a small experimental scale. But to have a meaningful impact they must be scalable to provide a significant percentage of US or world transporation energy need. If you mean battery electric vehicles, the overall efficiency isn't any better than modern internal combustion engines. E.g, power plant generation efficiency 40%, transmission line efficiency 95%, charging efficiency 88%, vehicle efficiency 88%. This gives overall BEV energy efficiency of .4 * .95 * .88 = 33% By contrast a modern diesel automotive ICE using common rail or piezoelectric injection has about 40% thermodynamic efficiency. Fuel production and processing is about 92% efficient, vehicle efficiency 88%, for an overall efficiency of about 32%, roughly the same as a BEV. Another problem: even if BEVs use spare night generation capacity to recharge, it's not saving petroleum. The capacity is spare because the plants are throttled back at night. More nighttime demand to recharge BEVs necessitates burning more fossil fuels to service that. There's also insufficient generation capacity to recharge a nation of BEVs. Total annual US gasoline energy consumption is 1.83E16 joules (5.63E15 watt hours). A 1 gigawatt power plant produces 8.76E12 watt hours per year. It would thus require about 642 new power plants to service that, or a combination of those plus using existing unused night capacity. In either case you'd be burning nearly as much fossil fuels in power plants as diesel cars would consume.

It varies widely based on biofuel yield per acre of the feedstock crop. The highest yield per acre is biodiesel from algae, which could be grown in hydroponic ponds in unused southwest US desert land. Biodiesel required to provide 100% of US transporation energy: 141 billion gallons Biodiesel from algae yield per acre:14,500 gallons per acre Land area required: 15,000 square miles (38850 square km, or 9.6 million acres), roughly 1/8th of the Sonoran desert in southwest Arizona. http://www.unh.edu/p2/biodiesel/article_alge.html Corn ethanol is considerably less efficient from a net energy balance and yield per acre standpoint. Corn ethanol required to provide 100% of US transporation energy: 250 billion gallons (adjusting for lower energy content) Corn ethanol yield per acre: 101 gallons per acre Land area required: 3.8 million square miles (2.47 billion acres) http://www.bioproducts-bioenergy.gov/pdfpresentations/Net%20Energy%20Balance%20of%20Corn%20Ethanol_Shapouri.ppt (PPT format) Total US area including Alaska is just 3.5 million square miles, so it appears impossible to provide all US transporation energy from corn ethanol, simply because of insufficient fuel yield per acre. Biodiesel from algae also has the advantages of better net energy balance, and could be located in non-arable land. Biodiesel from soybeans or rapeseed has the same problem as corn ethanol -- low yield per acre. I've seen various ethanol yields per bushel; I used 0.75 gallons per bushel, obtained from a USDA document. However even if it were 2 or 3 gallons per bushel, the required land area would still be much of the US.

Yes there is no center. More info: Question: Can we find the place where the Big Bang happened? Answer: http://curious.astro.cornell.edu/question.php?number=71

"Ask a Cornell University Astronomer: What is the universe expanding into?" http://curious.astro.cornell.edu/question.php?number=274

Various estimates place remaining conventional reserves at roughly 1 trillion to 1.7 trillion barrels. World consumption is about 30 billion barrels per year. http://en.wikipedia.org/wiki/Oil_reserves At current consumption rates that would exhaust supplies in 30 to 50 years (assuming no peak, just straight consumption). Consumption increases at about 2-3% per year, so the remaining supply won't even last that long. The peak theory is you don't have until oil runs out, but long before that production will decline, and the mis-match between demand and supply will grow ever more acute. Prices will skyrocket beyond anything we've ever experienced and never come back down. It's likely some form of this will happen, but for three reasons it will probably be much less severe than some apocalyptic predictions: (1) As prices go up, this impacts consumption. We already saw this during the 1973 and 1979 oil crises. No it's not pleasant, and yes it's an economic impact. But it's not an overnight thing; it will have a somewhat gradual onset. Things will adjust, consumption will moderate, cars will become more efficient based on economic incentive alone. Yes it's better to move proactively, but it ultimately will happen anyway. (2) There are vast remaining nonconventional oil reserves -- tar sands and oil shale. Various estimates place these at 5-10 trillion barrels, far more than existing conventional oil. There are definitely issues with energy balance harvesting these (energy in vs energy out), and environmental issues. The main reason nonconventional oil isn't used now is simple economics -- accessing them costs more than conventional oil. However whenever oil persistently stays over about $70/barrel, nonconventional oil becomes economically viable. Actually the price of conventional oil today is high enough to make nonconventional sources viable. But during an oil price peak a few years ago, energy companies made huge investments in nonconventional sources, only to have oil prices crash, and left them with huge losses. Thus today they're not going to repeat that until they're absolutely positive oil will never drop below about $70 per barrel. (3) Biofuels are theoretically scalable (economically and physically) to supplying all world transportation energy. This differs from solar/hydrogen or solar/wind where it's highly questionable they could economically or physically be scaled that large. However biofuels will not be vigorously pursued (at least in the US) until economic factors force that. The good news is there's enough oil in nonconventional sources to last over 100 years at current consumption rates. The peak oil theory does not consider those, so it should really be revised. More good news is nonconventional oil is largely located in the west, so that will permanently end the west's reliance on middle eastern oil with the attendant political, military and economic complications. Other good news is biofuels (at least certain ones) can theoretically provide all needed transportation fuel in an economically viable manner, using existing distribution and vehicle technology. http://en.wikipedia.org/wiki/Biodiesel http://www.unh.edu/p2/biodiesel/article_alge.html The bad news is the peak oil theory as stated (for conventional oil) is probably essentially correct, although the exact timing isn't that clear. There is uncertainty about how much is recoverable. There's further uncertainty about the achievable energy balance during extraction (energy in vs energy out). Also extracting nonconventional oil has major environmental problems. But so does burning trillions of gallons of gasoline and trillions of tons of coal PER YEAR, and we're doing that right now. The other bad news is biofuels, nonventioan oil, etc. will likely not be vigorously pursued in a huge industrial manner until economic factors force this. http://en.wikipedia.org/wiki/Peak_oil http://en.wikipedia.org/wiki/Tar_sands http://en.wikipedia.org/wiki/Oil_shale

Since there's been so little substantive contribution in this thread, I'm posting below a few relevant links addressing the original question. Hopefully that way people finding this thread will at least have something of value: Shape of universe: http://map.gsfc.nasa.gov/m_uni/uni_101shape.html Cornell astronomer: If the universe is infinite does that mean there is an infinite number of "me"s? http://curious.astro.cornell.edu/question.php?number=476 What was there before the Big Bang and what is there outside of our universe? http://curious.astro.cornell.edu/question.php?number=166 What is the universe expanding into? http://curious.astro.cornell.edu/question.php?number=274 Why isn't the sky bright at night if the universe has so many stars? http://curious.astro.cornell.edu/question.php?number=375

They typically generate AC at the exact frequency and voltage needed for the utility grid. This requires either (a) exactly controlling the turbine speed, or (b) allowing variable turbine speeds but having a AC/DC/AC converter to create AC output of the proper frequency. More info: http://en.wikipedia.org/wiki/Wind_turbines

Certain mental disorders have a significant biological element. This is very clear from "twin studies" where identical twins are separated as infants and raised in different environments. Identical twins have the same DNA. Despite growing up in totally different environments (differing homelife, nutrition, education, etc), if one twin develops schizophrenia, there's about a 50% chance the other will. If one twin develops bipolar disorder, there's about a 40%-70% chance the other will. Those probabilities are far above the background population, and cannot be influenced by environment since the twins are reared separately. The only item in common is DNA. Why isn't the concordance 100%? Because environmental factors such as stress can trigger the disorder that would otherwise remain latent. One twin may not experience the stress that causes his condition to surface. Also if all mental disorders were purely psychiatric, purely biological/pharmaceutical treatment wouldn't work. Yet over and over we see a good percentage of patients helped by these, even in cases where they are treated without their knowledge. For example in the 1950s, doctors noticed depressed patients treated with a new tuberculosis drug called iproniazid were getting better. At first they thought the patients were just happy their TB was cured. Further study showed even non-TB depressed patients improved. The point is many patients treated without even knowing they were taking an antidepressant, yet they got better. Why? Because iproniazid is an MAO inhibitor that alters neurotransmitter levels in the brain. There's definitely a place for psychiatric "talk therapies", but the evidence is overwhelming that certain mental disorders have a significant biological component. In some cases such as autism, MRI shows physical, anatomical differences in the brains of affected patients.

BTW, the Wang "Memory Capacity" paper can be found here (PDF): http://www.enel.ucalgary.ca/People/wangyx/Publications/Papers/B&M-Vol4.2-HMC.pdf

As already stated, there's no standard size. However here's a paper showing various sizes/costs/outputs of industrial wind turbines (PDF): http://www.eere.energy.gov/windandhydro/windpoweringamerica/pdfs/workshops/2004_wind_diesel/company/lorax.pdf The smallest is 30kw, so that's much bigger than a single residence would use. Wind turbines have an average capacity factor of 23%, so over the course of a year they produce about 23% of rated power. Therefore a 30kw turbine would produce 30 kw * 8760 hr/yr * 23% = 60.4E6 watt hrs/yr. A residential house uses on average about 10,000 kilowatt hr/yr, so a 30kw turbine could on average power six homes, and that assumes 100% efficient storage (batteries, etc). Size of a solar photovoltaic array of similar output is calculated: Overall solar cell efficiency: 10% (crystaline cells can't be used in large industrial quantities due to cost. Amorphous cells would generally be used. Also must use real-world efficiency, not laboratory efficiency). Also solar cell output degrades several % per year, so after 20 yrs output is about 1/2. Thus 10% is quite optimistic. This also assumes 100% efficient battery storage and 100% efficient DC/AC inverters. Average solar insolation in US southwest: 5000 watt-hrs/m^2/day, or 1.8E6 watt-hrs/m^2/year Annual solar cell power: 186,000 watt hrs/m^2/year http://www.wattsun.com/resources/insolation_maps/flat_plate.html Solar array size to produce 60.4E6 watt hrs/yr: 60.4E6 / 186000 watt hr/m^2/yr = 324 square meters, or a square array 18 meters per side. That assumes you live in the southwest US. Insolation for much of the US averages about 1/2 of that, so in those areas array size would be about double, or 648 square meters, or a square array 25 meters per side. So a 30kw wind turbine in a favorable area could power about 6 average homes. An equivalent solar array would be 324 square meters (southwest US), or a 648 square meters (much of non-southwest US).

See discussion in this thread: http://www.scienceforums.net/forums/showpost.php?p=236371&postcount=25