Wikipedia:Reference desk/Archives/Science/2015 August 20

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August 20

Natural Resources and the Environment

What have natural resources got to do with the environment?

125.255.167.126 (talk) 04:57, 20 August 2015 (UTC)

Start with Natural resources, then read Environment, then come back if you have any more specific questions. Vespine (talk) 05:14, 20 August 2015 (UTC)

Effects of alcohol on sleep and breathing

Why do people breathe heavier and snore during sleep after they've been drinking? Some also report feeling confused after drinking. Is this all because it affects the brain? 94.14.212.97 (talk) 07:42, 20 August 2015 (UTC)

Ethanol is a depressant, a substance that acts to suppress the operation of the central nervous system. All of the effects you describe are caused by that process. More information can be found at Alcohol intoxication, which covers both the effects and the mechanisms of how drinking alcohol affects your brain. --Jayron32 12:23, 20 August 2015 (UTC)

no future for things like computers, mobile phones, touch tablets, will our technological advance reverse severely in the next 20-30 years?

Computers mobile phones, touch tablets, car batteries and flat tv screens, all need metals like indium, lantan, neodym and rare earth metals. i have read in a scientific magazine that all those thing will end if we continue producing the same amount as today. even if we recycle those metals (many has already been lost) there wont be enought to continue our technological advances. does that mean like this?=

• 2050 Computers mobile phones, touch tablets, car batteries and flat tv screens are luxury for the very rich with no coal and what remains of oil will make long distance transport too expensive so no economic globalisation, a hyper severe economic crisis and then meybe without technology and good economy we will go back to feudalism? Dannis243 (talk) 11:29, 20 August 2015 (UTC)

(I have undone the hatting/closing of this thread. I encourage any respondents to respect WP:CRYSTAL and refrain from giving opinions, but feel free to provide relevant references. Responses that violate our guidelines may be removed.) SemanticMantis (talk) 14:14, 20 August 2015 (UTC)

You might be interested in reading about Rare_earth_elements. In short, they are not that rare, they just rarely occur in sufficient density to make extraction profitable. One way that is currently being developed to get more rare earth elements is Deep_sea_mining for polymetallic nodules. SemanticMantis (talk) 14:03, 20 August 2015 (UTC)

Additional info on the other things at peak oil, peak coal. Peak phosphorus is one that is less famous, but perhaps just as important. Hubbert_peak_theory covers the general concepts of eventual decline in extraction rates. SemanticMantis (talk) 14:11, 20 August 2015 (UTC)

It's also unlikely that we'll continue to need those exact same elements as the technology advances. Many of the uses of those weird materials are in things like magnets for vibration motors, batteries and touch-screens. All three of those things are being continually and radically re-engineered as time progresses. With the high pressure to drive down prices (there are smart-phones selling in India for $30 right now), there will be considerable research efforts into using more common resources as these other materials start to become harder to find, and hence more costly.

If you really want to worry about running out of resources - copper is a huge worry, we use it for circuit boards, wires, electric motors, water pipes and electrical transmission systems. When that runs out, we're in deep trouble - and we only have a 25 to 60 year supply. Without copper, almost nothing that modern civilisations do would be unaffected.

It's also the case that we shouldn't worry about running out of coal or oil (you touched on that). We can't burn more than a small fraction of what's left without wrecking the planet anyway. It's not shortages of those materials that's the problem - it's having people not use things that are relatively plentiful supply because in order to preserve the common good. SteveBaker (talk) 16:35, 20 August 2015 (UTC)

We have an article on peak copper too. Have a source for that 25-60 year supply claim? Also, unlike coal and oil, copper can be recycled after use in many applications. SemanticMantis (talk) 18:09, 20 August 2015 (UTC)

Maybe try reading the article you just linked to? Also Copper#Reserves. Recycling is definitely going to be needed - and it's already happening...but a lot of it ends up mixed up with a lot of other stuff (electronics, motors, wiring, plumbing) that can make it hard to extract. But as the price rises, doubtless we'll be doing much more of that. SteveBaker (talk) 20:42, 20 August 2015 (UTC)

Thanks. Peak copper doesn't give the range you did, though copper#reserves does. If you'd just include references in your post (there are many unreferenced claims), I wouldn't have had to ask. SemanticMantis (talk) 22:51, 20 August 2015 (UTC)

For the biggest users of copper, other metals will do. Bauxite being plentiful, price shifts will shift usage. No, the world economy of the next hundred years offers many serious worries, but the disappearance of smartphones for lack of metals is among the silly ones. Jim.henderson (talk) 16:51, 20 August 2015 (UTC)

Aluminium (which is what you get from Bauxite) can replace copper in a few applications (long distance/high voltage power cables, for example), but it's not without problems. In the 1970's, aluminum wiring was used in some new US homes - but these days, finding that the house you just bought has aluminium wiring is a costly problem because you're gonna be pulling it all out and putting copper in it's place. Aluminum wire explains the many, many problems with this. Aluminium suffers surface corrosion within seconds of exposure to the air - but that surface corrosion prevents deeper corrosion issues - but in situations where small cracks can develop, it's a problem. Aluminium is hard to solder to - so it's a poor choice for electronic circuit boards. Aluminium is also a likely contributory factor to Altheimers' - so we're not likely to be using aluminium water pipes. You need thicker aluminium wires to carry the same amount of current as copper - and it's not as flexible - so aluminium is a poor choice for electric motors, generators and transformers. I could go on. Suffice to say that Bauxite (as a source of aluminium) may help us stretch the remaining supplies of copper - but it's not going to come close to replacing it. SteveBaker (talk) 21:14, 21 August 2015 (UTC)

yes, we _are_ moving full steam ahead towards feudalism and pre-Modernity, but paucity of resources has nothing to do with it. The Enlightenment project by which man emerged from pre-Modernity has been pretty much scrapped and given up on Asmrulz (talk) 19:26, 20 August 2015 (UTC)

Soil Desalination

What is it? How does it work? What other technicalities are there to it? The previous page redirects to 'Soil Salinity Control', which does not explain the concepts of soil desalination. 122.109.141.77 (talk) 12:24, 20 August 2015 (UTC)

Here's [1] a patent that discusses several older methods, and proposes a new method that they claim is better. SemanticMantis (talk) 14:06, 20 August 2015 (UTC)

Soil desalination is removing salt from dirt, presumably for agricultural purposes (most crops people eat do not grow well in soil with a high salt content). StuRat (talk) 14:21, 20 August 2015 (UTC)

Thanks. I couldn't find any other references on the web. I really appreciate this. 122.109.141.77 (talk) 07:24, 21 August 2015 (UTC)

You're quite welcome. StuRat (talk) 00:24, 23 August 2015 (UTC)

Resolved

What is a "cassette" in regard to molecular cloning/DNA?

Sometimes when talking about plasmids or DNA sequences, authors mention a "cassette". What parts constitute the cassette in this context? I have a plasmid with a promoter followed by genes encoding a fluorescent protein and an antiobiotic resistance gene with a 2A site between them both. If I transfer this part of my plasmid into another plasmid, am I transferring a "cassette"? My interpretation of Expression cassette is that my sequence is not a cassette because it doesn't include a 3' UTR. Thanks. --129.215.47.59 (talk) 14:43, 20 August 2015 (UTC)

A quick PubMed search for the first paper with plasmid and cassette turns up [2], a free article which attributes the term to Hicks, J., Strathern, J. & Herskowitz, I. (1977) in DNA Insertion Elements, Plasmids and Episomes, eds. Bukhari, A. I., Shapiro, J.A. & Adhya, S. L.(Cold Spring Harbor Laboratory, Cold Spring Harbor, NY), pp. 457--462. Unless I overlooked something this is very much the same as what we describe in Mating of yeast. The situation is a bit more complicated as you see there because the other copies are actually silenced; in any case the boundaries of the cassette seem poorly defined since only the alpha/a part is really different.

My gut feeling would be that the part of a plasmid that is invariant, the vector in other words, would be the equivalent of a tape player, and whatever you swap out between your constructs to determine what song you're playing today is the cassette. (Hmmm, thinking about that further it is tricky. With something like pBluescript/pGEM where you have T3 and T7 promoters on either side, it's clear your insert acts as a cassette in the classical sense. The "vector sequence", if you really want to be anal about it, might exclude those promoters because they're not needed for replication or transmission of the plasmid; they're part of the payload. BUT, if someone says they found vector sequence in something you uploaded to GenBank, odds are it's sequence near those two promoters...) If your sequence truly doesn't have a 3'UTR and gets translated right off the end of the RNA, it can still be a cassette, I'd say. I don't think there are very many hard and fast rules on the use of language in biology. Wnt (talk) 15:47, 21 August 2015 (UTC)

Difference between remanufacturing, refurbishment and renovation

What's the difference between remanufacturing, refurbishment and renovation? Remanufacturing and Renovation don't state a difference, and Refurbishment is just a disambiguation page to product specific forms. — Sebastian 17:19, 20 August 2015 (UTC)

There is some distinction described in the articles - Remanufacturing usually refers to a product, and restoring it to original specifications. Common things remanufactured or "rebuilt" include engines, pumps, and other machinery. In contrast, renovation usually refers to a structure or building, and often the original form is intentionally left behind - e.g. adding in a new type of counter top, cabinets, or additional pantry when renovating a kitchen. When you remanufacture an engine, it should be as close as possible to how it came from the factory. When you renovate a house, you do whatever you want with it. SemanticMantis (talk) 18:01, 20 August 2015 (UTC)

Thank you, that makes sense. So, apart from the difference of which objects the terms usually refer to, remanufacturing is a subset of rebuilding. What about refurbishment? — Sebastian 18:24, 20 August 2015 (UTC)

I think that's more subtle and subjective. According to wiktionary "refurbish" [3] could be seen as a superclass of remanufacturing and renovation. My short electronic NOAD gives "refurbish - renovate and redecorate (something, esp. a building)". You can refurbish a house or a cell phone, but you don't renovate a cell phone, and you don't remanufacture a house. Remodeling a house is essentially the same as refurbishing it, but we don't don't remodel cell phones! Confusing isn't it? I guess one clear distinction is that remanufacturing is reserved for things that are manufactured. You might consider putting all these words into Etymology online [4] to gain insight on where they come from. SemanticMantis (talk) 18:34, 20 August 2015 (UTC)

Formal semantics aside - generally, if you purchased a "remanufactured" cellphone or laptop, you'd probably expect that a bunch of old phones/laptops had been dismantled into smaller components, which would then be tested, and the good components put into a production line where "new" products would be made from "used-but-carefully-tested" parts. Generally they'd use entirely new cases and buttons and such to avoid dings and scratches. A "refurbished" device would probably just be tested as an entire unit and have any failed or limited-life parts replaced. So a refurbished laptop might have a new hard drive and replacement fans and air filters, been blown with compressed air to get rid of any fluff inside, then reassembled with a set of new batteries (you'd hope!) and sold. "Renovation" generally would refer to some historical object that is being made to work again. So, I might have an old Osborne 1 computer that you'd like to get going again as a curiosity piece - and maybe it needs a new 5" floppy drive and a power supply to get it going again. Maybe you wouldn't be able to find an original power supply - so you'd replace it with a modern equivalent...that's what I'd call "renovation"...in the context of electronics.

But cars are only ever "restored" and houses only ever "renovated" unless they are historical houses, when they might be "restored". "Restoration" implies "restoring"...returning something to it's original, factory condition where "renovation" (coming from the word "nova" for "new") would imply making something new again - but without necessarily sticking with it's original design.

SteveBaker (talk) 20:36, 20 August 2015 (UTC)

Thanks everyone, those explanations make sense to me. — Sebastian 01:09, 21 August 2015 (UTC)

Proof in blood or elsewhere that a diet is working?

Suppose a person is living with a calorie deficit, of say, 300 per day. Is there a way to show from where the body is getting the extra 300 calories it needs? Will there be changes of anything in the blood or urine or saliva or elsewhere that shows that either protein from (presumably) muscle and/or fat are being mobilised? Will there be a measurable difference in these indicators if someone has a deficit of 600 calories in a day? 78.148.109.33 (talk) 18:01, 20 August 2015 (UTC)

You can determine whether more fat or muscle is being metabolized by calculating body fat percentage at the start and then at intervals after. Hydrostatic_weighing is one method, Whole-body_air_displacement_plethysmography is another. SemanticMantis (talk) 18:05, 20 August 2015 (UTC)

During fat metabolism, the body will also undergo Ketosis, which can be detected in blood chemistry. --Jayron32 18:11, 20 August 2015 (UTC)

Isn't Ketosis only entered in fairly extreme conditions when blood glucose is nearly absent? I know OP said 300 kcal, but would ketosis be occurring and detectable with only mild caloric limitation? I guess I'm asking for clarification about "Ketosis is... where most of the body's energy supply comes from ketone bodies" - I don't know if ketosis happens any time fat is metabolized, or only in the case where glycolysis is not occurring. SemanticMantis (talk) 18:26, 20 August 2015 (UTC)

Ketosis occurs in most Low-glycemic diets, including Low-carb diets, those aren't necessarily "extreme". A person could be receiving enough caloric and nutrient intake from non-carbohydrate sources, but the lack of carbohydrates will keep blood glucose low, and result in higher rates of ketosis. Part of the rationale behind such diets is that the body does not really distinguish, in the blood stream, in where a nutrient comes from, so a body in ketosis will digest fats from all sources, dietary and internal. --Jayron32 18:51, 20 August 2015 (UTC)

Starvation response--Aspro (talk) 18:45, 20 August 2015 (UTC)

My wife and I did a week-long juice-only "Reset" diet...you could smell the ketones on our breath after a couple of days! SteveBaker (talk) 19:33, 20 August 2015 (UTC)

@SteveBaker: Hmmm, given that juice is usually high in carbohydrates (sugars), and ketosis is associated with a lack of carbohydrates, I reserve skepticism. Wnt (talk) 15:55, 21 August 2015 (UTC)

Not fruit juices - veggy juices, kale, carrot, that kind of stuff. Not a lot of *anything* actually. SteveBaker (talk) 16:14, 21 August 2015 (UTC)

Carrot juice (which I love) might as well be fruit juice, although there's no added sugar, its calories are 90% from carbs. This website: http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2757/2 give excellent information for all sorts of food, even takeout, which Stu often asks about. BTW, I have lost 20 lbs since february, and 55lbs since this time last year, on an extremely restricted low carb diet. I eat all the meat and green veggies I want. As for tracking progress, I recommend a bathroom scale. A good endocrinologist can prescribe all sorts of new medicines for weight loss, I'd recommend seeing one very strongly. μηδείς (talk) 22:06, 21 August 2015 (UTC)

SteveBaker is absolutely right. Even though carrots are high in carbohydrates, those are locked up as starch and so don't end up in the juice (as they are processed raw) Google it! The evidence of a low carb diet can (will defiantly) be smelled by the nose. Perhaps, not a good enough reason to sleep with one's Swedish, French or Mexican au pair but the halitosis can not be ignored. It is very pungent. So carrots juice is not equivalent -in any way- to fruit juice.--Aspro (talk) 22:50, 22 August 2015 (UTC)

Congrats on the weight loss ! This Q, though, was about how they can tell if they are losing fat or muscle mass, and a scale alone won't help with that. You can have yourself weighed in water and compare that with your normal weight, and I believe the ratio tells you your body density. Since fat is lighter than muscle (and water), you can infer your body fat percentage from that. (The tricky part of weighing yourself in water is fully exhaling so you don't float due to the air in your lungs.) StuRat (talk) 22:16, 21 August 2015 (UTC)

Well, I sure as hell didn't lose no 55 lbs of muscle. Thanks for the encouragement. I feel like a prophet new inspired. Yeah, I get the point about which sort of weight loss. But after a certain amount you can tell you are loosing fat on a long term; any quick fad-diet type weight loss is suspicious and may be unsustainable. The best thing is to see a nutritionist and an endocrinologist to test for things like hypothyroidism as well as pre- or actual diabetes type II. If the problem is metabolic there are some incredible drugs that have come on the market even in the last 5 years that work wonders. If it's cosmetic weight loss, there are all sorts of fora, but I'd talk to a personal trainer at a gym if possible in that case. μηδείς (talk) 01:10, 22 August 2015 (UTC)

Their you have it. For people who have more money than sense and can afford to spend oodles of money on experts, rather than coming back to nature and taking note of the paleolithic diet- which is free and easy to follow just pay the self-appointed experts. If one wants to have a day long feeling of satiety, with one's glands performing as evolution designed them to do and maintain a good looking figure -just eat proper foods!</rant> ruddy experts <//rant> --Aspro (talk) 23:17, 22 August 2015 (UTC)

I don't think it's appropriate to give medical advice, so I'll simply say that when my A1C was 7.5 (above 7 is considered diabetic) my general practitioner prescribed the normal treatment which made me put on about 10 lbs a month for about five months. The OP has mentioned blood work, which makes me think something doctorworthy is going on. A specialist switched me to an exenatide (literally, a Gila Monster venom analog) and a gliflozin class drug helped reverse the trend, along with the aforementioned meat and greens diet. These drugs may be totally inappropriate for others, I am not a doctor. If the OP has a medical condition, or suspects he has a medical condition, he should see a specialist who can determine what is right based on his needs and other factors. μηδείς (talk) 03:37, 23 August 2015 (UTC)

Fora as in plural of forum ? I am on a low carb diet myself (particularly low in grains), but only on alternate days. Lost 40 lbs so far. StuRat (talk) 01:36, 22 August 2015 (UTC)

Wheelock's Latin, bay bee. Congrats on the 40. I will be happy if I can lose 40-50 more, then I will be in the same shape I was in my early twenties. μηδείς (talk) 21:58, 22 August 2015 (UTC)