The question I would raise to this (and it's one I'm sure nobody can conclusively answer) is what are the long term effects of this? Ie. evolutionary effects? If we take Advil every time we have a fever inducing illness, is it possible that our immune systems will grow dependent on the Advil in future generations? I know that various forms of medicine have been around long before what we consider modern medicine arose today, but is it possible with the intense concentration of medicine and our dependence on it, we could see immune system failure in future centuries? Is there any way this could be connected to the rise of the AIDS pandemic? I may just be dumb or paranoid, but it's something I've always wondered. Also, don't be like ghettoastronaut and feel the need to give me concrete statistics or anything. If you are in science and can speculate from an informed point, feel free.
No. I have no statistics for you but as Morbo would say, "IMMUNE SYSTEMS DO NOT WORK THAT WAY." Advil actually works by suppressing the immune response to a small degree. In terms of fever, it blocks the production of cytokines in the brain's thermoregulatory centre, which would otherwise reset the body's internal temperature control mechanism so that you develop a fever. Other aspects of the immune system - T cells and B cells and their entourages - set to work killing invading pathogens. Advil by no means enables the immune system to start killing pathogens, so it's rather hard for your immune system to become dependent on it to work. Could it be connected to AIDS? Again, the question doesn't make sense. The HIV virus blocks your immune system in such a way that it doesn't know how to fight an infection. Take as much or as little advil as you want, it's not going to make a difference. As a matter of curiosity there is a small subset of the population who, while they can contract HIV, will not progress to AIDS because of (I think) a mutation of the T cell receptor which the HIV virus attacks. If HIV were to become sufficiently prevalent you probably would see some sort of evolutionary pressure favouring this population, but it would take a long ass time. As for the evolutionary standpoint; I honestly can't see this happening. Even if we assume that the immune system could possibly become dependent on advil, considering how vital the immune system is to human survival, I would think that there would be so much genetic conservation surrounding the immune system that any mutations that require advil for the immune system to work would be sufficiently rare, and their consequences sufficiently damaging, that they wouldn't be fit enough for the organism to reproduce. The only way it could happen is if the mutation were benign so that there was no difference between those with the advil-dependent immune systems and without, and then genetic drift could potentially take over so that the genotype would have a large prevalence. This would also take a fuckload of time. Humans might not be around in the time it would take this to happen.
I hate my wife's fucking cats. One likes to piss all over our garage. Is it safe to use bleach to clean the urine? I always assumed it would produce chlorine gas, but would the gas still be produced if the piss was dry?
In the morning I drive east and the sun is bright as shit. I typically get home before sunset, but last night I was traveling out of town and heading west as the sun was setting. The sunset wasn't nearly as bright. Why is that? I'm assuming that it's kind of an optical illusion since in the morning the sun is higher in the sky before I can see it due to buildings and whatnot. When I was driving towards the sunset all that was in front of me was 70 miles of fields and a few trees, so the sun was much lower. Also, in the morning the sun is almost directly in front of me and in the evening the sun was maybe 20 degrees to my right. Maybe the combination of those 2 variables gives me my answer? Also, since I'm on the subject, why does the sun (or any bright light for that matter) cause me to sneeze. Some people don't have that reaction to brightness, so what exactly causes it?
I think that the key here is the sun was much lower when you were looking at the sunset. When the sun is lower the light has to travel through more atmosphere so, due to scattering within the atmosphere, the intensity of the light is less.
Credentials: close to getting my bachelor's in chemistry, but this is well within the grasp of anyone who's had a semester of organic. I can't comment on specific pasteurization processes and how that affects skunking, but here's what I know purely based on chemistry: beer has compounds called isohumulones that contribute to the bitter flavor (wikipedia tells me 1 IBU=1ppm of isohumulones). If you look at the structure of isohumulone, you'll see there are a few places that would be good for radical formation. Radicals are usually formed when light hits a molecule, causing a C-H bond to split. The compound remains neutral, but that carbon now has an extra electron floating around that can form a bond. Also, for isohumulone it would be an allylic (adjacent to a C=C bond) radical formed, which is more stable and more likely to form. This radical can pick up an -SH group (from an enzyme I think), converting it to a thiol. Sulfur-containing compounds tend to smell/taste like shit, so you get the skunking effect. That's an abbreviated but still way too in-depth explanation of why beer skunks up. Radicals can also form from heat. So while warming a beer up to room temp might not have much of an effect, if it gets hot it could have the same effect.
The ammonia compounds will still be there in a solid/dehydrated state, so yes, it could still produce chlorine gas. Use vinegar and water to clean it up, and visit a garden supply place to get a product that will discourage them from visiting/peeing in those areas. Usually those contain some kind of citrus oil, so they'll smell good to you as well. Pet supply places will have the same kind of products, but for some reason the nursery/garden places charge quite a bit less.
You're exactly right in your reasoning. In the city, or if the sun rises over high terrain to the east of your location, by the time you can see it you're getting direct rays, hence the brightness. If the sun is rising or setting over a low, far horizon, you're actually seeing rays that are filtered through a much, much, longer distance through the atmosphere, are being scattered much more, and are even being bent through the atmosphere, as the edge of the atmosphere where it meets space acts like a lens. That's also part of the reason that the sunrise/sunset is red in color.
Not certain this is in the right place Is anyone on the board a geologist, or know one? I'm thinking about going back to school and geology's looking more interesting by the day, would like to ask a few questions. thanks, AFHokie
I was just reading an article about the oil spill that is currently taking place in the gulf, and I was wondering if any of you had any experience with oil wells or can answer this question: Don't oil rigs have some kind of safety feature that shuts off the flow at the source no matter how far down it is? Apparently, this leak is a mile below the surface and that is why they are having such a hard time stopping it. Don't they have a contingency plan in place for something like this? If not what do you think a "worst case scenario" could be? I've never been in on the whole green thing, or been one to jump on the hate big oil bandwagon, but Jesus, this is shaping up to be a disaster of epic proportions and I'm a little pissed off about it. On an unrelated note, I have been seriously considering rigging my house to go "off grid" and I was wondering, how would you calculate how much solar power you would need to run a house completely, including a central air conditioning system. I recently saw a solar generator system for a little over 1500 bucks and I can't help but think stringing a few of those together would be pretty ideal. I have a fair amount of land, and a small wind generator would not be out of the question in addition to solar.
I can actually help out on both of those. All wells, including the undersea well that is leaking, have a device called the wellhead that is installed at the top of the well (in this case, on the sea floor) and controls the flow coming out of the well. From what I've read about this incident, the wellhead that is leaking was manually controlled by operators on the platform, and didn't have some of the optional safety features that many other wells do. While not required in the gulf, in the North Sea all wellheads are required to have an acoustically triggered system that closes the wellhead automatically when it senses an explosion. There are also some other redundancy systems that the BP well in the gulf didn't have. BP claimed at the time that the safety features were too expensive, and weren't needed because an accident like this was almost impossible. The wellhead is probably controlled hydraulically, my company manufactures the special mile-long hose assemblies needed to connect the controls from the platform. Apparently the explosion severed the control lines, or otherwise disabled the controls, preventing them from closing off the wellhead. They are now trying to figure out another way to close off the wellhead, not an easy task since it's too deep for divers. They've tried to close the blow-off preventer which is installed on the wellhead with a remotely operated submarine, but so far haven't been able to get it closed, possibly due to damage on the wellhead itself. They've also discovered additional leaks in part of the pipeline that connected the wellhead to the now-sunken platform. Their plan now is to drill a new well to relieve the pressure that is pushing the oil out of the current wellhead, and install a steel dome to contain and capture any more leaking oil. Another option is to drill a new well that intersects with the current one, and then pump drilling mud into the hole, plugging it and stopping the oil. Any of these options will take a week or two, as the steel dome needs to be fabricated and/or new drilling operations need to be set up. As far as the "off-grid" question goes, you need to start off with the basic, overall picture. Take a look at your electric bill and note the number of kilowatt-hours you used. Then, look at the specs on the solar generator or wind generator systems to see how many kilowatts they generate. For the wind system, you'll need to know your average wind speed, and the average number of hours per day the wind blows. For the solar system, you need to know the average intensity of the sunlight in your area, and the average number of hours per day it shines. Then you'll take all that data, and figure out the size/quantity of those systems needed to produce the number of kilowatt-hours you consume in a month. Then you'll probably want to double that to make up for inefficiencies in the systems, and losses due to storing the electricity. If you plan on being entirely off-grid, you'll need a large bank of deep-cycle batteries to store the energy produced in the daytime/when the wind is blowing and then provide that power when there's no sun/wind. You'll also need to have time to devote to keeping the solar cells clean and free of dust, snow, etc. Just a thin layer of dust can reduce the output of a solar cell by a huge amount. As an electrical engineer, my suggestion for you is not to try and go entirely off-grid. You can hook up a solar or wind generator to provide part of your energy needs, but still have regular electric service for when the sun/wind don't cooperate. Also, relatively speaking, electricity is cheap. Take the generating capacity of the solar system, and multiply by 8-12 hours per day of good sunlight to get your kwh/day that it can generate. Multiply that by the price your electric company charges per kwh (from your bill) and that is your savings per day from the system. Then divide the cost of the system by that number to find the number of days it will take for you to break even. My guess is that it will take a very long time. Do the same thing for the wind generator. At this point, small, individual-scale wind and solar plants just aren't financially feasible in all but the most extreme circumstances. Solar panels are expensive, and very inefficient. Mechanical wind turbine systems aren't as bad, but they're still pretty inefficient.
There have been some advancements in materials that have doubled the efficiency of photovoltaic cells, but even the most advanced cells only convert about 40% of the solar energy they absorb into electricity. In the US, we get about 100 watts per square foot of energy from the sun, so a typical solar cell will only produce about 20 watts per square foot. Hopefully, continued advancement in that area as well as the protective coatings for the panels will bring higher efficiencies, lower production costs, higher durability, and reduced maintenance costs. At this point, it's just a matter of waiting for the technology to be developed and implemented in a large enough scale to bring the prices down. Just to give you a rough idea, my electrical consumption for a 1450 sq ft house in Texas is roughly 1400 kwh per month, and I use gas for heat, hot water, and cooking. In order to generate that amount of electricity with existing solar cells, lets assume the cells are collecting 20 watts per square foot, and your location gets 240 hours of good direct sun per month. Even with a power storage system that's 100% efficient, you need roughly 6kW of generating capacity, or about 300 square feet of solar panels. Based on some prices I'm finding online, you're looking at roughly $30,000 to install enough solar panels to keep your home running. Here in TX electricity is going for about 8 cents a kwh, so you're looking at about 22 years before you break even, if your system even lasts that long. Commercial solar power farms don't use photovoltaic cells, they use a large array of mirrors that are on computerized mounts. The system shifts the mirrors as the sun travels through the sky to focus the reflection on a central tower. Kind of like using a magnifying glass to focus the sun's energy on an ant. The central tower contains salt, which is molten due to the heat generated by the mirror array, and that molten salt is pumped through a heat exchanger to produce steam that drives conventional turbine generators. Believe it or not, that's a cheaper way of producing electricity than regular solar cells. Hopefully some of the research being done now will lead to great new technologies in the near future. I'm sure solar panels will continue to improve, and it won't take long before we reach a point where they can become more commonplace. Give it 10 years or so, look at the advances in computer processors from 1990 to 2000, if advances in solar cells come anywhere close to those, we're going to be in good shape.
Another interesting possibility is solar power using Stirling engines. A stirling engine is placed at the focus of a parabolic mirror and uses the heat to convert to mechanical motion. The good thing about these is that they are modular. The number of mirror/Stirling engine units can be tailored to the requirement.
Monty Hall This is probably not in the right place for this. And I have looked around a bunch of places for a definitive answer to no avail. Deal or no deal and Monty hall problem I was watching Deal or no deal with my roommate, and he insisted that the contestant should switch cases when down to the final 2. Given that there was 100 in one case and 1 Million in the other, initially the contestant would have a 1/22 chance of choosing the million, after eliminating 20 other non-1Million cases the probability would be 21/22 of being in the other case. (This is just taking the monty hall problem many steps further, meaning choosing one door then the host opens a wrong door, gives you a chance to switch, making your chances 1/3 of winning with no switch, and 2/3 with switch) So my question is if it matters if the host picks a known wrong, or if it is randomly selected. Possibly similar, easier version: If there were just 3 cases, you pick one, its not the million, should you switch (according to monty hall fall no)? What makes that different from the regular Monty Hall? http://wizardofodds.com/askthewizard/tvgames.html http://en.wikipedia.org/wiki/Monty_Hall_problem http://probability.ca/jeff/writing/montyfall.pdf Thanks
Re: Monty Hall Basically, the Monty Hall problem assumes that the host will open an undesirable case/door. Deal or no deal has no such assumption, he could have easily opened the case that had the million inside. Because of this, all cases have an equal probability up until the end, and switching makes no difference. Edit: I should probably have explained this a bit better. Lets assume the monty hall problem with 4 cases (to show that it does work with more than 3). You pick one, and have 3/4 chance of "losing". The host opens one which he knows is a loser. There are now 3 cases left, each with 1/3 odds of containing the winner. You can switch or stay here, it doesn't matter yet. If he was to open another case, it's just the usual monty hall problem as if you started with 3. If you run that with 4 cases and the host picks at random, you have 1/4 probability of picking the winner initially and the host has a 1/4 chance of removing the winner for you. Down to 3 cases, its 1/3 even. Down to 2, its 1/2. Adding up the probabilities, you see that you have 1/4 chance of winning regardless of what stay/switch decisions you make throughout. You can't skew the results by switching at the final case as in the monty hall problem.
I am shopping around for a solar system, and this is what I have come up with. For approximately 3000$ installed, I could take care of 75% of my hot water usage, which includes infloor heat in the basement and the garage. This in turn would lower my heating cost, since I would use this to heat the house to a degree. For approximately $10 000, I could install solar panels that would take care of 75% of my electrity requirement. In order to take the next step, I would have to invest approximately $30 000, since I would need batteries and more solar panels/wind turbine. If stay on the grid, I don't need half the equipment, nor do I need to have 100% capacity for peak times. For me, the worse case scenario would be a very cold week, with no sun and no wind.
When looking for a new solar system, probably the most important consideration is the star at the center. You're definitely going to want a main sequence star that isn't about to collapse or go nova. You'll probably want to stay with a yellow star to support familiar plant life. This is trick if you plan to stay in the milky way galaxy because 85% of the stars are red dwarfs. Your next important consideration is the availability of suitable planets or moons in that solar system. Obviously you'll need liquid water and an atmosphere containing somewhere in the area of 20% oxygen with the remainder being an inert gas. Survivable temperatures are also important. Fake edit: oh, you meant a solar electricity system. Nevermind
Re: Monty Hall Don't you still want to switch in this situation? Even if there aren't only two boxes left, you still want to switch after the host opens even one. Consider 1,000,000 boxes in which the host opens up 999,997. No way you're keeping your original box, but there are still more than two unopened boxes. The idea is that, by opening even one box, the host is giving you information. Namely, that he won't open your box if it's a winner. EDIT: Here's what I'm saying. http://en.wikipedia.org/wiki/Monty_Hall_problem#N_doors