Wikipedia:Reference desk/Archives/Science/2006 October 30

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October 30

Industrial Processes

Why industrial processes are continous rather than batch?

Not all are. DMacks 16:16, 30 October 2006 (UTC)

I'm not sure if I understand your question, but perhaps our assembly line article would help? -- SCZenz 17:31, 30 October 2006 (UTC)

There are many of both types. Continuous processes may be more difficult to design or operate, but when working well can have advantages in terms of efficiency, throughput per capital investment, or other advantages. ike9898 18:10, 30 October 2006 (UTC)

Continuous processing is preferred over batch processing for a few reasons, but as said above there are times when batch processing is unavoidable. An example would be an electronic device where a circuit board is glued into a case, and is then tested to see if it operates properly. The glue used must be cured in a warm oven, and so you "batch" a large amount of glued assemblies together and put them in the oven. After they have cured, you take them out, then you take the devices and one at a time you install the wires and test each one.

The oven curing is a batch process. The process of installing the wires and testing is a continuous process.

Now the batch processing is not preferred because let's say something goes wrong with the glue mixture, and it doesn't cure properly. You will not know it until the entire batch comes out of the oven, and so you lose the cost of manufacturing all those pieces. However, in a continuous process like installing the wires and testing, you discover any failed parts right away, and can correct the problem before an entire batch is ruined. 192.168.1.1 6:54, 30 Rocktober 2006 (PST)

See float glass for a good example of a continuous industrial process. Makes better quality glass than batch methods, but you need to be making a lot of glass to make the investment in plant worthwhile. Plus when you shut a float glass plant down for maintenance it takes literally months to get it back into production again. Gandalf61 09:24, 31 October 2006 (UTC)

Natural instinct of a right handed person

It was suggested by someone to put this question to a Biologist. Please I would appreicate any input to this question.

I have been falsely accused of pushing someone. The Police report states that I extended my "left" arm, and put my "left" hand on his chest and pushed him. This never took place, and this person has no clue if I'm right handed or left handed. I'm "right" handed.

I have argued to my Attorney that I would NEVER approach or defend myself with my "left", due to it would be a natural instinct to use the arm and hand with the most strength and coordination.

Please how can I try to prove or atleast give the Jury doubt this every took place?????

Joy Justen

I know this isn't the answer you're looking for, but if I were an investigating police officer, judge, or jury member, I'd hardly care about which arm was used for pushing. I'd be far more interested in the circumstances surrounding the push. -- Chris 16:53, 30 October 2006 (UTC)

I see the point the question, but it seems like too weak an argument to do you much good. If you could have pushed with you left hand, the question is whether or not you did.(This is not legal advice!) ike9898 18:07, 30 October 2006 (UTC)

Hello, and welcome to Wikipedia. It is an encyclopedia, not a source of legal or medical advice. In fact, at the top of the Reference Desk (this page), it states "If requesting medical or legal advice, please consider asking a doctor or lawyer instead." Please follow this direction, it helps both you and Wikipedia. Thank you, and again, welcome. -Fsotrain⁰⁹ 16:59, 30 October 2006 (UTC)

Hes not asking for legal advice, please dont use these replies, they are desperately irritating. He is infasct asking for scientific help, for use in a legal situation, however, the situation in which he wishes to use the content we give him, is irrelevant. Philc _T^E_C^I 18:40, 30 October 2006 (UTC)

Yeah, and the red "welcome to Wikipedia" makes it seem like he's not welcome.

I'm kind of confused by the situation and why "instinctual" is an important distinction, but in my experience I've used both right and left arms instinctually. Think of how awkward this would have been when humans were evolving if their handedness gave a predisposition for defense so that if a tiger approached from the left then those who instinctually defended themselves from their right would be less likely to survive. As far as arguing for your innocense, arguing that you're right handed is not going to convince anybody that you couldn't push with your left hand. Ƶ§œš¹ _{[aɪm ˈfɻɛ̃ⁿdˡi]} 20:46, 30 October 2006 (UTC)

In fact, there's a good chance the left hand could be instinctive, as if the body felt threatened, it would try and keep the danger as far away from the heart as possible. The dominance of R. handedness has in fact been originated by some professors as being due to the fact that the left hand was busy holding a shield to protect the heart in ancient warrior tribes, so the right hand had to be used for all other tasks (opening doors, writing, swinging swords), and, whether by nature or nuture, passed to future generations, or that attacking someone with the left hand evolved to be a "surprise mechanism"; if everyone attacked with their right hand by default, someone who then used a sudden left hook could take an assailant by surprise. Our article on handedness has some other interesting viewpoints, although I'm not sure they'd help your case... Laïka 21:42, 30 October 2006 (UTC)

Actually, I think it is just as likely that a right handed person would strike/push with their left hand, even more so if the person has had any fight training. Most fighting techniques actually see a right handed person lead with their left hand, whether it is boxing or almost all of the martial arts, the most basic 'stance' has the left hand forward, closest to your opponent. My guess here is that any prior incidents, if any, and the allegations surrounding the incident will have more weight then what hand you supposedly used. I suspect there is a lot more to the story then you're letting on since I doubt you go to court for 'pushing' someone, if you did and you had no prior assault convictions you'd walk with maybe a slap on the wrist. If you have priors and there is more then just a push then you're probably not as innocent as you make out, whether you actually pushed someone exactly as claimed or not. Vespine 23:26, 30 October 2006 (UTC)

I'm fairly sure that those basic stance don't mean you use your left to strike first, because that also makes your right hand punches more powerful with the aid of your waist and body. --Wirbelwindヴィルヴェルヴィント (talk) 03:28, 31 October 2006 (UTC)

Note that only Laika has addressed the actual question, which is which hand one would use to push someone instinctively, so out of reflex. Let's not speculate on details we don't know anything about and focus on the actual question, which certainly is interresting enough. DirkvdM 08:49, 31 October 2006 (UTC)

Those words will definitely come back to haunt you, Dirk.  :) JackofOz 09:00, 31 October 2006 (UTC)

Well, may be you did use your left hand to push him because you were using your right hand to hold something (like a knife or a gun :-) ). I am just pointing out that a RH person may still use the LH under some circumstances like this. -- Wikicheng 10:22, 31 October 2006 (UTC)

I'm not a lawyer but lawyers I do know would probably say that these sorts of explanations — somewhat ad hoc and based on roundabout circumstantial explanations — almost never work with juries (unless you happen to be O.J. Simpson, but that's another story). I doubt it is a line of argumentation work pursuing — it looks pedantic, and would be easy enough to wriggle out of ("Oh, did I say left? I meant right. As you know, his right is the same as my left. Simple enough distinction, but I was pretty upset by the whole incident when I made the report."). And on top of that I honestly doubt you would be able to get a scientist of any credibility to say "well, there's absolutely no possible way that a right-handed person would ever use his left arm to push someone — it's totally outside the bounds of plausibility!" --Fastfission 15:33, 31 October 2006 (UTC)

Evolution and Organo Metallic Complexes?

What do you suppose is the earliest point in evolution where complexes between biotic materials and metals formed were? essentially, the earliest instance of natural bioinorganic chem.?--172.135.162.223 16:46, 30 October 2006 (UTC)

This is quite complex, as most organic substances derive from inorganic carbon, oxygen, hydrogen &c. Any metal becomes organic when it enters an organic cycle of assimilation - and later, desassimilation (coal was organic carbon too).

Begin with the history of life and try with any chemical as iron, used in hemoglobin : my naïve thought is that animals needed blood to use it, they had to have a heart, blood vessels ... -- DLL ^{.. T} 20:07, 30 October 2006 (UTC)

personally, i'd say before day 1. there is a theory floating about that the break from racemic primordial ooze to chiral ooze happened due to asymmetric catalysis of biomolecule forming reactions on mineral surfaces. if this is the case, then metals may have helped get life started. other than that, some very crucial enzymes (eg. superoxide dismutase, catalase, DNA polymerase, many more) use metal cofactors, so the involvement was probably quite early in the piece. And some ribozymes (thought to be a possible way early life worked) need a magnesium ion cofactor in order to function. Xcomradex 20:41, 30 October 2006 (UTC)

Of mice and lab rats

Is it possible to breed lab rats to have a genbetic predisposition to specific metabollic defects and / or diseases?Readerofbooks 16:59, 30 October 2006 (UTC)

Reverse genetics explains a bit about the breeding of genetically engineered mice. Knock-in and knock-out mice are used to try and gain a better understanding of metabolic disorders. As for diseases, I suppose one could alter components of the immune system. Mmoneypenny 20:07, 30 October 2006 (UTC)

Yes, not only is it possible, but such mice are currently being used. One odd side effect is that some of these genetically engineered mice are quite valuable, and treated with great care, as a result. My brother works at the University of Michigan, and tests fire alarm systems. He has special rules to follow for testing around the "million dollar mice", so as not to upset them. StuRat 22:37, 30 October 2006 (UTC)

Respected sir, your question is clearly an allusion to the Steinbeck novel 'Of Mice and Men'. Sir, please! -- the reference desk is no place to be showing off your literary knowledge. Please see Wikipedia is Not For Pedants. This is your last warning. -- Chris 23:44, 30 October 2006 (UTC)

My name is Rick Block. I am not running for office anywhere in the United States and I approve of this joke (if you do not live in the US and/or do not understand this reference, please accept my apologies for interrupting your RefDesk reading - and, I'm jealous). -- Rick Block (talk) 04:51, 31 October 2006 (UTC)

See, for example, Jeffrey M. Friedman's obese Ob mouse. Which made him a very rich man indeed. Rockpocket 05:41, 31 October 2006 (UTC)

If you please, I came here to become informed and not to be amused by someone's awkward attempt at humor. Even your claimed moniker, "Rick Block" indeed has the feel of a made-up portmanteaux: are you a (B)rick or a (B)lock or do make your living by breaking (B)locks with (B)ricks? I'm sure that now that your nefarious intent has been exposed Mister Brick Breaker of locks, and your claim to not be running for office becomes suspect. It is well known that everyone with such made-up names such as you lay claim to yours is obviously running for office in the upcoming US elections or you would have a less contrived name. You don't fool us Mister "Rick Block", we know that the world is held up on the back of a turtle who is standing on yet another turtle. It's turtles all the way down Mister (B)lock and your attempt to convince us otherwise is futile indeed. Go on to your assuredly election defeat for that is what you deserve. "I'm not running for office" indeed - that's what they all say. Fool me once, shame on you me, fool around again then shame on... a mind is a it's terrible to lose ones mind. So there! heidi n joe

Oncomouse was the first patented mammal — basically a rat with a very high disposition to getting cancer. Great if you are doing research on cancer and cancer-causing agents. --Fastfission 15:28, 31 October 2006 (UTC)

latinized names?

How come animals and plants are all given "latin"-ized names, wouldn't it be better to use either real latin, or just name them according to a western dialect? -- Sfelos 17:07, 30 October 2006 (UTC)

See Binomial nomenclature. howcheng {chat} 19:49, 30 October 2006 (UTC)

There were not Roman names for the vast majority of plants and animals in the world. At the time Latin was used for scientifically naming plants and animals, it was the common western dialect for scientific writing, much as English is today. alteripse 21:46, 30 October 2006 (UTC)

Caffine/Keeping awake

How much does the effectiveness of caffine vary from person to person? as recently I drank a litre of energy drink to keep myswelf awake, which was a 300mg dosage, then fell asleep after finishing the bottle, to be honest I had expected more from this.

What other off the shelf products can I use to combat tiredness, noting the relative ineffectivness of caffine in my case?

Thanks Philc _T^E_C^I 18:12, 30 October 2006 (UTC)

We have a really neat article on Caffeine, that answers all your questions! I question their assertion that 2-3 cups of coffee constitutes an overdose! Come on! (typed in 2.3 seconds!). --Zeizmic 18:19, 30 October 2006 (UTC)

I did, the overdose is under the amount I took, at roughly 250mg, but that doesnt answer (either of) my question(s) now does it. In fact the only variation of effectiveness from person to person the article mentions is as a result of tolenrance adaption, but as I almost never ingest any caffine, this is not going to have effected me. Philc _T^E_C^I 18:27, 30 October 2006 (UTC)

The tolerance probably varies quite a lot in the same way that the tolerance for all drugs does, in particular central stimulants. And that's not just the adaptive tolerance. It's highly individual thing, regardless. Plus there's a fairly big psychological component, not least for caffine. Anyway this isn't the place for medical advice, but if you're young and don't have any heart problems, you can probably go ahead and take as much as you want as long as you do it slowly and carefully. You'll know you've had enough once you start noticing the negative side effects, like increased heart rate, blood-pressure, shaking, nausea, palptiations, etc. That's the definition of an overdose, not some specific number (which is just an average). -I know several drugs which I barely feel the effects of until I'm at a dosage that'd O.D. most people. That said, I think you might be expecting too much. Caffine can keep you from falling asleep, but it doesn't really keep you 'awake' in the sense that your mind is clear and able to work properly. In other words, it's more akin to insomnia than anything else, in my opinion. --BluePlatypus 19:28, 30 October 2006 (UTC)

I would second the conclusion that 'not falling asleep' is different from the kind of stimulation that caffeine offers. For example, if my body is loaded on high Glycemic index nutrients (caffeinated soda included) then I can expect to be promptly put to sleep when the sugars deplete, no matter how alert my nerves are. Blood sugar is a much more important factor (for me at least) than caffeine when it comes to feeling awake/tired, and no I am not diabetic. --Jmeden2000 20:26, 30 October 2006 (UTC)

You need to distinguish measured blood glucose from your imagined "blood sugar". You may or may not be surprised to know that nearly everyone's confident self-perceived blood sugar levels have little relationship to measured blood glucose levels. You are likely attributing feelings to blood sugar that would be more accurately attributed to other systems such as level of autonomic arousal or level of various mood-affecting neurotransmitters. The popular american folk medicine concept of "blood sugar" is like the traditional chinese folk medicine concept of "heat"-- the former has no objective connection with measured blood glucose and the latter has no objective connection with body temperature even though the words suggest so and the ignorant think so. alteripse 21:43, 30 October 2006 (UTC)

How do we 'hear ourselves think'?

Everyone has at sometime or another had the annoying experience of not being able to read something without being aware of 'hearing' the words we are reading in our head. Eventually we go back to overriding the voice that accompanies our reading activities and aren't consciously aware of it most of the time.

My question is simple : How does this work? If we normally detect sounds by variations in air pressure as it enters the ear, how are we able to 'hear' things inside our brains with no external influences?

The same way that you can see and hear things in a dream. The brain is capable of activating the same sorts of neural pathways that are activated while actually hearing something or actually talking, when nothing is happening externally. Without this, you wouldn't be able to get songs stuck in your head, plan out actions or designs before doing them, or do any multitude of other useful mental things. Mirror neurons are an interesting example of this type of thing in action; people watching a sports game, for example, might actually have the motor sections of their brain light up, despite not being part of the action. -- Consumed Crustacean (talk) 19:06, 30 October 2006 (UTC)

(edit con) You dont sense with your body, you sense with your brain, your ears detect vibrations, but not sound as such, you brain converts this information recieved in the ears into what we experience as sound, it can potentially convert any information it wants into this experience. And as such we can experience sounds were there are none, i.e. thinking. Philc _T^E_C^I 19:09, 30 October 2006 (UTC)

The word/article you're looking for is subvocalisation (subvocalization for the spelling-impaired :) ). GeeJo ^(t)⁄_(c) • 22:46, 30 October 2006 (UTC)

Consider this: a normal person may "hear" the words he thinks, or the words he reads, and correctly attribute the origin thereof.Normal hearing is the brain assigning meaning to nerve impulse patterns coming from the ear. A schizophrenic person may "hear voices" and attribute them to the CIA or God, but with similar origin to the previous. Edison 04:39, 31 October 2006 (UTC)

So, we don't actually "hear ourselves think", we "think" with the sound-processing portions of our brain and nervous system. This only applies to people who have learned to think in this way - deaf people for instance tend to think in sign-language. --Ronz 02:12, 2 November 2006 (UTC)