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My home compound microscope is manufactured by Apex, it's the Researcher model. The build quality is really excellent for the price, and the optics are indistinguishable from the nikon or leica optics in the much more expensive scopes at work. I spent a long time checking out the competition before buying, and that was the best one I could find within my price range (it's much cheaper on Amazon or eBay than the manufacturers site). I'm fairly sure the same scopes are distributed under the brand Amscope in the USA. This one (eBay link) looks exactly the same as mine and a lower price than I paid, but I can't vouch for the quality of the glass or whether it will even use the same objectives. Actually, I just check their website and the exact one I have (but the American version) is this one. They claim that "This microscope is made by the same technicians and on the same production line as optical instruments for Leica, Zeiss, Nikon and Olympus". If true, that might explain why the optical quality on mine is so good. Also, the one you linked to in your first post is monocular, but you could easily get a good binocular within your price range.

Disinfection in our labs means reducing the microbial load but not necessarily killing all microorganisms or their spores. As opposed to sterilisation, which kills all the microorganisms and their spores.

I strongly agree with SMF - if there are qualified dermatologists giving you advice you should follow it. I would only add that it might help to get all your bed linen and clothes sterilised or thoroughly washed, and give your house a thorough clean, so that if you are diminishing the problem on your skin you aren't then immediately getting reinfected from your environment.

I think it's very unlikely to be related. Truffle farming is a rather unusual case, but most mycorrhizal fungi (e.g. pretty much all the mushrooms you've ever seen on the ground) will be interacting with the roots of many plants simultaneously, with their mycelium network covering a very large area. This is different with some truffles which require specific host species, because if you are outside the natural range of the those species you might have to plant the host tree yourself. In that case there would be a limited supply of carbon to the fungus (but I still don't think it would affect fruiting body size). Generally the range of sizes of a fruiting body is genetically determined, with environmental factors impacting the size within the range. It would be more likely that a small available carbon pool would lead to fewer fruiting bodies being produced (because the fungus would cover a smaller area).

This is a sweeping and false statement. There are a large range of pesticides used in organic agriculture, many of which are also used in intensive agriculture, and many of which are highly specific. There is certainly no credibility to the claim that organic pesticides are more harmful. Bacillus thuringiensis spores are used as an organic insecticide, probably the major one. These are not only also used in non-organic agriculture as well (Bt-crops are engineered to express the Cry proteins which give B. thuringiensis its insecticidal action) but they are highly specific. They affect only larval forms of Lepidoptera (moths and butterflies), although some strains also affect larvae of other insects such as mosquitoes. By contrast there are many non-organic pesticides which are harmful, persistent and non-specific. Atrazine is a current example, and the historical record is appalling (DDT, dieldrin, chlordane, etc which were only outlawed internationally in 2004 with the Stockholm convention). By all means let's dispel the myths surrounding organic agriculture, but let's not introduce more in process.

That's because the car displaces a volume of air, and is followed by a region of low pressure. As the car goes past air from the area surrounding its path flows into the low pressure region behind the car, and if you're standing close you get pulled along with the moving air around you. At least that's what I always figured was happening, perhaps someone else can put it in more formal language and correct the details.

Yes, it was a reply to your post.

I think part of the reason they are making things more transparent is because they have to. We live in an age when secret communications are no longer secret - at any moment things could be made public by an interested group of amateurs. Clearly the government has no intention of covering up some transgressions by making some data public. It's not only cynical, but totally unrealistic to think that the whole of government is conspiring to allow a small minority of MPs to overclaim on expenses. But aside from the need to beat the leakers and hackers to it... it's good for the democratic process to keep government transparent and open to scrutiny, and it promotes trust and social cohesion. If they are geniunely are trying to do their best, they have nothing to hide. I think the fact that this is obviously a transient government has made them feel like they've not got much to lose, and they can make brave decisions.

Well you can use liquid nitrogen to achieve all sorts of temperatures. How about exploring the cryotolerance of goldfish? You could use a range of different temperatures and freeze the fish at each temp for a range of different times. Then you can see if there is a max time it can be frozen for, a minimum temp it can be frozen to, and see if there's a relationship between freezing temp and freezing time. You could identify the ideal temp for long term freezing too. How long do you have to do the project? Can help with the aim if you like the idea... Also you could explore those parameters for different species of fish - you could choose one from a climate which might experience freezing and another from a climate which doesn't experience freezing, then compare their survival from cryopreservation. You could also see if freezing affects their survival or behavior afterwards

All of your questions (except the one about LSD making you smarter) are answered extensively on Wikipedia. Start by reading the LSD page. Then you can read about the CIA testing, project codename MKULTRA. As for medical effects, it is used therapeutically, but the USDA states that it... "produces no aphrodisiac effects, does not increase creativity, has no lasting positive effect in treating alcoholics or criminals, does not produce a 'model psychosis', and does not generate immediate personality change." Here's the document. There is some non-clinical suggestion that it might help stop the cycle of cluster headaches in chronic sufferers. Here's a paper about it. Flashbacks are not the result of the brain releasing LSD, it is not produced in the human body (see this paper for experimental evidence). But the actual mechanism of flashbacks and the related disorder Hallucinogen Persisting Perception Disorder (HPPD) are not understood. Pharmacologically, LSD binds to dopamine receptors, adrenoreceptors, and most seratonin receptors. It's all in the pharmacodynamics section of the wikipedia article. From personal experience - it's pleasant to take once if you're a confident, happy person. The visual and physical sensations are completely unique. If you're depressed or anxious it amplifies those feelings and turns them into an experience. I've seen a lot of people take it and invariably the ones who aren't completely happy or confident going into it have a terrible or terrifying experience. I'm quite certain that consistent use over time has driven some people I know to clinical psychological disorders, including paranoid schizophrenia. How well do you know yourself? Are you completely in control of your mind and emotions? If yes, proceed with caution. If no, do not proceed.

Err, no, fruit growers burn tyres to protect the crop from frost (as I already explained and referenced). Seriously, google. Plants don't experience heat shock unless the final temperature is higher than ~40°C (although it varies with climate), and even then most species will not until considerably higher temperatures. A clear winter morning means there is no cloud cover, so frost is more likely. Frost is a major concern for fruit growers, growing ice crystals damage cell membranes and make fruit soften and bruise, becoming unsellable. You can lose a whole crop overnight. So, on cold nights, or clear nights which indicate a possible cold morning, they heat the susceptible areas of their orchards. I work at the Royal Botanical Gardens and our estates team were doing this all through winter (with a piped heating system, not tyres) in the orchards. I would be surprised if the person writing the physics book knew that fruit growers used to burn tyres but did not know why, and based a question around a misunderstanding. Thus, the answer is the one I gave earlier. But there might be more interesting explanations as to how thick smoke can help prevent frost.

Well the major hint is that ppm stands for parts per million. So, if you have 3.80 x 102 ppm CO2 that means for every 106 (1 million) particles, 3.80 x 102 of them are CO2. So the fraction of any volume of air which is CO2 will be [imath]\frac{3.80 \times 10^2}{10^6}[/imath] Then if you want to find out how many molecules of CO2 are in any volume of air, you multiply the total number of molecules in that volume of air by your fraction. You've been told 1m3 air contains 2.6 x 1025, so to find the number of CO2 molecules in 1m3 of air you do [imath]\frac{3.80 \times 10^2}{10^6} \times 2.6 \times 10^{25}[/imath] Then you can go through the same procedure for H2O. Does that make sense? It's a good idea to get your head around these sorts of calculations, you use them a lot in science.

"Fog or smoke Clouds and fog are well-known for their ability to reduce radiative heat loss from the surface. Smoke from smudge pots or burning tires or refuse and mist from fine water nozzles have been used in attempts to reduce this heat loss. Since it is difficult to maintain the smoke over the sensitive crop area and to produce droplets the optimum size to intercept the long-wave radiation, this method is not very effective. In addition, our environmental laws now prohibit the use of this method, where smoke is involved." from http://www.omafra.go...5-116.htm#freez and... "A smudge pot (also known as a choofa or orchard heater) is an oil-burning device used to prevent frost on fruit trees. Condensation of water vapor on particulate soot prevents condensation on plants and raises air temperature very slightly." From the Wikpedia Smudge Pot article.

OK, how about this one (saying GM foods are possibly unsafe and current methods inadequate to ensure food safety): Dona & Arvanitoyannis (2009) Health Risks of Genetically Modified Foods And here's an extensive review of GM crops, section 3 is about food. It concludes that there is no proven risk: Lemaux (2008) Genetically Engineered Plants and Foods: A Scientist's Analysis of the Issues These two papers seems to directly disagree about a few things. I'll be in the chat room from about 8-10pm GMT today and can help you then if you still need it and aren't happy with the references you have so far. But in advance you should be repeatedly searching citation databases until you find some good references (that's what I'd be doing). Start by searching Google Scholar. Just try different combinations of relevant keywords and trawl through the results. Then try Web of Science. If you really can't find any decent sources for and against this particular issue then you'll have to choose a different question.

Sure thing. After further reading it's clear that the level and type of damage to DNA depends on many factors including: Whether the DNA is isolated or in cells Strand length Whether cryoprotectants are used Duration and number of freeze-thaw cycles It seems as though ice crystals are more likely to cause damage to genomic DNA in cells. Free DNA in suspension is less likely to be damaged by ice, but the medium is important. There are also damaging effects due to dehydration of cells and free radical production if whole cells are freeze-thawed. Here are some of the articles I read: Anchordoquy, Thomas J., Lorinda G. Girouard, John F. Carpenter, and David J. Kroll. 1998. Stability of lipid/DNA complexes during agitation and freeze-thawing. Journal of Pharmaceutical Sciences 87, no. 9: 1046-1051. doi:10.1021/js9801891. Calcott, Peter H. 1986. Cryopreservation of Microorganisms. Critical Reviews in Biotechnology 4, no. 3: 279-297. doi:10.3109/07388558609150797. Calcott, Peter H., and Anne M. Gargett. 1981. Mutagenicity of freezing and thawing. FEMS Microbiology Letters 10, no. 2: 151-155. doi:10.1111/j.1574-6968.1981.tb06227.x. Cox, C.S., and R.J. Heckly. 1973. Effects of oxygen upon freeze-dried and freeze-thawed bacteria: viability and free radical studies. Canadian Journal of Microbiology 19, no. 2: 189-194. doi:10.1139/m73-029. Grecz, Nicholas, Teri L. Hammer, Christie J. Robnett, and Mel D. Long. 1980. Freeze-thaw injury: Evidence for Double strand breaks in DNA. Biochemical and Biophysical Research Communications 93, no. 4 (April 29): 1110-1113. doi:10.1016/0006-291X(80)90603-8. Krajden, Mel, James M. Minor, Oretta Rifkin, and Lorraine Comanor. 1999. Effect of Multiple Freeze-Thaw Cycles on Hepatitis B Virus DNA and Hepatitis C Virus RNA Quantification as Measured with Branched-DNA Technology. J. Clin. Microbiol. 37, no. 6 (June 1): 1683-1686. MAZUR, P. 1984. FREEZING OF LIVING CELLS - MECHANISMS AND IMPLICATIONS. AMERICAN JOURNAL OF PHYSIOLOGY 247, no. 3: C125-C142. Ross, K S, N E Haites, and K F Kelly. 1990. Repeated freezing and thawing of peripheral blood and DNA in suspension: effects on DNA yield and integrity. Journal of Medical Genetics 27, no. 9: 569 -570. doi:10.1136/jmg.27.9.569. Seutin, Gilles, Bradley N. White, and Peter T. Boag. 1991. Preservation of avian blood and tissue samples for DNA analyses. Canadian Journal of Zoology 69, no. 1: 82-90. doi:10.1139/z91-013. Sleight, Sean C., and Richard E. Lenski. 2007. Evolutionary Adaptation to Freeze‐Thaw‐Growth Cycles in Escherichia coli. Physiological and Biochemical Zoology 80, no. 4 (July 1): 370-385. Zilli, L., R. Schiavone, V. Zonno, C. Storelli, and S. Vilella. 2003. Evaluation of DNA damage in Dicentrarchus labrax sperm following cryopreservation. Cryobiology 47, no. 3 (December): 227-235. doi:10.1016/j.cryobiol.2003.10.002.

Something out of nothing is not a problem, unless you are trying to relate it to something you have directly experienced. Similarly, "the concept of 'before the big bang' is nonsensical because time emerged in the big bang" is not a problem either. There could be an eternally cycling series of bangs, but why does that make any more sense than a spontaneous event in which time and space emerged from nothing? It's just a problem of imagination, and to me it's no easier to imagine infinity than to imagine something arising with no cause. They are both outside our direct experience but you just accept the concept as there's no reason why it shouldn't be so. The 'something out of nothing' idea is different from the religious assertion because religion adds an invisible, undetectable entity before the other stuff which caused all the other stuff. Just an unnecessary and stupid complication.

Does it have to be the same culture going for a week? Or can you just innoculate a fresh flask every couple of days?

Yes, sorry I shouldn't have assumed you were thinking of modern western military.

If you have long DNA strands, repeated freeze-thaw cycles can create ice crystals which can shear the strands. Usually if working with DNA which has been frozen in a -80°C you would take out the amount you need and keep it at 4°C until it was used up, rather than keep refreezing the same sample. In practice though, it takes quite a few freeze-thaw cycles before a DNA sample gets significantly damaged.

How long do you want to sustain the culture? You can keep K. pneumoniae going in litmus milk for a few days. It's essentially milk after all.

I think anyone is a hero who gives their life, which can include choosing a low-paid career and not necessarily dying, to do something which is genuinely in the service of others. Some scientists are heroes. Plenty of doctors are. I certainly agree that most policemen are not heroic, but it's far more likely that firefighters chose their job because they wanted to save lives. And they do, every day. I don't know why two of your examples are army related, I wouldn't class anyone in the modern western military as a hero. Soldiers who gave their lives in world war II, where people were genuinely fighting to save their fellow countrymen as opposed to securing foreign assets, they were heroes. There's a certain thrill and satisfaction which comes with a job where you risk your life. But being conscripted and then giving your life, that takes real courage. Most real heroes are the ones you never think about. People who are full time carers, or people who gave their lives, reputations or future happiness to prevent some catastrophe which never happened so we don't know they did it.

Are you only supposed to used two sources? Or do you use many sources supporting each side? Because we can certainly find more sources. I agree the first title is closer to the mark, but rather than credible (which means believable), you could say reliable or adequate. e.g. Are Current Methods of Testing Genetically Modified Foods Adequate?

One cheap way of doing it is just using packing foam pieces and tape. You could experiment at home with a pack of eggs, try different quantities of foam packed around the egg and then throw it into the air (outside) and see if it breaks. I expect someone with some engineering skills could come up with a much better solution.

I think that second essay is a fairly straightforward title. After all, life is essentially a system which emerges from the interactions of polymers with different structures. One approach would be to survey in general how repeated units in biological polymers can bond to themselves or other molecules to form larger structures. Then go into more detail with specific moleules. I would focus on (for example): DNA, how its strucure is important (double-strandedness, wrapping around histones etc) how enzymes work in general, and cofactors key examples of single subunit and multiple subunit enzymes... transport proteins (the different types all relate structure to function differently) ATP synthase Photosystem II Then you can pull back out to more general discussion and conclusion. The classic hour-glass essay structure is perfect for this sort of general question.

I admit it's certainly possible I've experienced it more times than I can readily remember. However, as others have pointed out your optic nerve has a greater potential lag difference than the possible difference between the time of light reception. Cool idea though! Keep coming up with them, they are interesting to think about.