The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
The microphyte/microalgae page had an illustration of Spirulina, a cynobacteria. Microalgae are algae, which are eukaryotic while cynobacteria are prokaryotic. The caption for spirulina also included dubious unsourced information about its health benefits. Aslo the algae page listed cynobacteria as both an "included group" and an "excluded group". These errors have all been corrected, but please let me know if I was mistaken. Greg Comlish (talk) 04:32, 9 March 2014 (UTC)[reply]
Note the second paragraph of algae, which begins "There is no clear consensus definition of algae." Many sources do include cyanobacteria in "algae," and these claims are sourced in the article. This is in old problem, and the best we can do on WP is acknowledge some of the issues of nomenclature. Still, it doesn't make sense to have a disputed member as an example, when there are plenty of unequivocal mycrophyta that could be pictured - So your edit to microphyte does seem to be an improvement.
I'm not feeling WP:BOLD at the moment, but expect your edit to algae to be reverted once enough people catch wind of it. The truth of the matter is, cyanobacteria are included as algae in some sources, and excluded in others. The list format did make it a bit confusing though. Perhaps the ideal compromise is to have cyanobacteria listed in both "included" and "excluded" sections, with both instances having a footnote that says "some sources include cyanobacteria as an algae, while others do not." -- but the place for this kind of discussion is Talk:Algae, where there is already a whole thread about "prokaryotic algae".
There's a reason why systematics and cladistics are used when biologists want to be careful about describing relationships and group memberships. "Algae" doesn't even have a taxonomic rank, it's just a "group", and a highly polyphyletic one at that. So -- I wouldn't lose too much sleep over trying to nail down a strict scientific definition of this known-to-be-problematic grouping. This is all basically covered in the first three paragraphs of algae, before you made any changes. SemanticMantis (talk) 05:41, 9 March 2014 (UTC)[reply]
sinuses and eyes
Recently when I was having an eye test the optician said casually, 'Of course you have sinus problems.' As a result I now wonder whether problems with sinuses affect eyes and/or eyesight. If so, how please? And if not, how did she know? Thank you in advance. — Preceding unsigned comment added by 78.127.60.178 (talk) 08:12, 9 March 2014 (UTC)[reply]
It need not have been anything to do with your eyes at all; people with sinus problems have a distinct nasally quality to their voice. It could be that your hair dresser would make the same remark. That said, there are obviously connections between eyes / nose / sinuses (see, for example, photic sneeze reflex) and irritated sinuses can lead to weepy or red eyes. I try not to go to my optometrist deep in hay fever season as I know I'll get weird results. Matt Deres (talk) 13:21, 9 March 2014 (UTC)[reply]
If a person's nose/sinuses are plugged up, their tear ducts may no longer drain properly, resulting in watery eyes, and they may also be suffering from a general allergic reaction or cold, either of which can cause red, itchy, watery eyes. StuRat (talk) 17:43, 9 March 2014 (UTC)[reply]
Thank you for your responses. They both adopt a commonsense approach but I must admit I was hoping for something more scientific. For instance, years ago, women taking the contraceptive pill experienced difficulties using contact lenses. It transpired that pregnant woman (which to their bodies, women taking the pill appear to be) produce a film over the eyes. This phenomenon was previously unknown. I wondered if there might be a more direct connection between the eyes and sinuses than normally supposed. — Preceding unsigned comment added by 78.127.60.178 (talk) 10:12, 11 March 2014 (UTC)[reply]
A point well-taken. Some PDE5 inhibitors (notably, Viagra) have the uncommon side effect of triggering rare anterior optic neuropathies, in some cases irreversibly causing loss of vision. It turns out eyes are linked to treatments for dysfunction of much more distant parts of the body than the sinuses. loupgarous (talk) 05:08, 12 March 2014 (UTC)[reply]
Hey, I asked a question here on the reference-desk yesterday regarding metals and railways and I got such good response that I was thinking I should ask another question related to metal. Something I have been thinking about for a while.
If one is thinking about taking up Blacksmithing, Goldsmithing or even Gem-cutting as a profession, what education would be needed?
Chemistry and metallurgy seem obvious, but what else, and where would be a natural place to start?
By the way, for any Wiki-modders out there who might read this, There doesn't seem to be an own reference page for questions related to 'Education'. If there is, then I must have missed it. Perhaps there should be? So science seemed the most natural place to ask this question.
Metallurgy is the general topic for metals, but that deals more with smelting, etc., whereas a blacksmith or goldsmith shapes existing metals, for the most part. Lapidary is the topic of dealing with gems. However, smithing and gem-cutting don't require advanced degrees, but rather you would look for an apprenticeship where you could learn from a master.
However, beware that much of this work is now either done in third-world nations paying minimal wages, or by machine. So, there are only a few jobs left in those fields that pay well. For example, you could own a jewelry shop that repairs wedding rings and such. (It would probably be cheaper for them to just buy a new ring, or send the current one overseas to repair, but the sentimental value prevents them from doing either of those.) StuRat (talk) 17:35, 9 March 2014 (UTC)[reply]
In the UK there are university courses in silver and gold smithing, but the normal route to black, white, tin, silver and gold smithing is via an apprenticeship. No formal qualifications may be needed, just an aptitude. --TammyMoet (talk) 19:23, 9 March 2014 (UTC)[reply]
Things that used to be industrial necessities are now done mainly as "artisan" crafts for fairly limited markets like decorations and people trying to do authentic restoration of historical objects. Modern steel plants and machine shops are about as far from blacksmithing as you can get. There are professional societies dedicated to keeping the old trades alive like the Artists Blacksmiths’ Association of North America and Society of North American Goldsmiths. Their websites will probably have links to educational options. Colleges with studio art programs will probably offer lapidary and basic metalworking classes. Some also offer glassblowing, probably fewer offer blacksmithing. Probably the only modern metallurgy class that will be particularly useful for a blacksmith would be a class on steel microstructures and phase transformations. The strength of steel is generally determined less by the alloying elements and more by the heat treatment. For working with gems, classes in geology would be more relevant - learning how to identify minerals, what causes color/shape. Mr.Z-man19:33, 9 March 2014 (UTC)[reply]
Blacksmithing is more of an informal trade. I remember in high school, the only future career listed that didn't require a high school diploma was blacksmith.--Aurictalk19:42, 9 March 2014 (UTC)[reply]
I know that these professions, at least blacksmithing, isn't the same as it used to be. In a way, I think it's a shame. But thanks for your answers. They were helpful.
Krikkert7 (talk) 22:31, 9 March 2014 (UTC)[reply]
See sources #26 and #27 in the MSG link in the title. One study showed it doesn't cause obesity in Chinese subjects, while another study shows that it does cause obesity in a similar group of Chinese subjects. So, if we assume both studies to be factually correct, does anybody know why there would be a difference in the conclusions ?
Also, has a study been done on the effect of MSG on Europeans or Americans ? My two thoughts are that they may react differently, due to genetic differences (with Orientals having been exposed to it longer and adapted better to it) or perhaps differences in diets. StuRat (talk) 18:16, 9 March 2014 (UTC)[reply]
What mechanism is offered? MSG is the salt of glutamic acid, certainly not a huge source or calrories, nor known to be medically active. Yes, it makes plain foods less plain. But so does salt and pepper. The two cuisines that use it most, Eastern and Italian (from Parmesan cheese and tomato sauce) do't seem particularly fat. I'd look instead at the influence of affluenza. μηδείς (talk) 21:07, 9 March 2014 (UTC)[reply]
Not sure about those studies, but previously I'd heard it stimulates the appetite, hence people being hungry again an hour after eating Chinese food. StuRat (talk) 21:16, 9 March 2014 (UTC)[reply]
Yes, you'll want to look at umami. But the notion is like saying that salt causes obesity. It simply makes less palatable foods more palatable, in this case signalling to the brain the presence (whether it exists or not) of proteins. μηδείς (talk) 21:53, 9 March 2014 (UTC)[reply]
At least for me, salt limits how much of an item I can eat. I get dry mouth and my lips start to crack. Drinking lots of water helps, but that fills me up a lot sooner. And knowing my blood pressure will spike as a result and I will feel veins throbbing in my head also makes me stop. StuRat (talk) 20:39, 11 March 2014 (UTC)[reply]
The study that did find a link looked at BMI vs MSG intake at a single point in time. The study that did not find a link looked at change in BMI over a 5 year period (as well as the baseline BMI). The study that did find a link surveyed 752 people from rural areas age 40-59. The other study looked at 1282 people ages 20+ from a mix of rural and urban areas, but only from one province. The second study also points out a potential issue with the first one: "A major criticism of the present study was that the total free glutamate (specified as glutamic acid) intake of the non-users compared with of the users of MSG was the same, possibly due to the fairly homogenous dietary patterns among the predominantly rural community, or it may have resulted from inaccuracy in the assessment of MSG intake."
In general, it seems like the main reason they choose China is convenience. Chinese people cook with MSG at home, so it's easier to measure how much they're actually eating. Westerners get most of their MSG in processed and restaurant foods. Mr.Z-man00:08, 10 March 2014 (UTC)[reply]
Acceleration of human evolution during Holocene
This paper claims that human evolution accelerated during the last 40,000 years. Unfortunately the paper is too technical for me. I was hoping someone could briefly summarize exactly how the researchers reach this conclusion ie how it is even possible to measure the rate of evolution. 65.92.5.74 (talk) 21:07, 9 March 2014 (UTC)[reply]
Well, if they can get DNA from fossils of various ages, they can determine how much of a change took place between each sample. StuRat (talk) 21:12, 9 March 2014 (UTC)[reply]
They measured the long-term rate of evolution by calculating the difference between human and chimpanzee DNA. They measured the rate of recent evolution by measuring the differences between the DNA of various modern human populations, assuming that all of them diverged from a relatively small unified African population around 40,000 years ago. I should note that the recent discovery of Neanderthal and Denisovan contributions to the DNA of some populations raises doubts about the validity of their analysis. (Their paper was published in 2007.) Looie496 (talk) 05:21, 10 March 2014 (UTC)[reply]
March 10
Early-diagnosis pancreatic cancer
After noting that early diagnosis is rare due to the lack of symptoms, the Pancreatic cancer article goes on to say that the 5-year survival rate for local disease is just 20%. The sourcing is solid, [1] and [2]. I'd previously assumed that the disease's low survival rate was due simply to the difficulty of catching it early, and that most people with an early-caught pancreatic cancer would survive, comparable to things like ovarian cancer (92.7% five-year survival when caught early, per the article) or melanoma ("the chance of cure is high" when caught early, per the article). Why is pancreatic cancer different? Nyttend (talk) 01:37, 10 March 2014 (UTC)[reply]
But that's the thing: "local disease" definitely sounds like "caught early", but you still have a 4-in-5 chance of dying within five years if your pancreatic cancer is caught early. Ovarian is really hard to catch early ("It is disproportionately deadly because it lacks any clear early detection or screening test, meaning that most cases are not diagnosed until they have reached advanced stages"), but that doesn't keep it from having a high 5-year-survival rate when caught early. Nyttend (talk) 02:59, 10 March 2014 (UTC)[reply]
I don't think that's the meaning in the article, because separate statistics are given for "locally advanced", which has a 10-month average survival rate. Judging by cancer staging, the latter is stages 2-3, while the "local disease" is stage 1. Anything below stage 4 is "not spread to other organs yet", and presumably the death rate for stage 3 is substantially higher for pretty much any cancer than is the death rate for stage 1. Nyttend (talk) 03:10, 10 March 2014 (UTC)[reply]
It helps to keep in mind that cancer is not one disease. It's basically a symptom--unregulated cellular reproduction. There are some 200 human cell types, hence at least 200 different types of cancer. It's very similar to talking of broken bones. Broken fingers rarely kill, broken necks and spies and hips and skulls moreso. Well overa year and a hald ago I asked about lung cancer that had spread to the brain. Chances were someone with that stage inoperable lung cancer with two separate spots in the brain had well under a 6 month average survival rate--she's in remission today.
As for people with pancreatic cancer, my parents, in their seventies, know at least 6 who have been diagnosed, and only one now living, and on his last legs. None lived more than two years from diagnosis, which in almost every case was asymmetric back pain. Who gets back pain and thinks pancreatic cancer? The other symptom is type 2 diabetes, which many people expect from lifestyle and family history. Here's a good article from CNN on th topic that killed Patrick Swayze and Joan Crawford Steve Jobs and is the fourth most deadly form of cancer after lung, breast, and colon: See . μηδείς (talk) 03:55, 10 March 2014 (UTC)[reply]
Um, is this real? I see a lot of online ads for "simple trick solves [huge health problem], so the use of "trick" in the headline makes me suspicious that it's spam. It also doesn't really answer the question. Nyttend (talk) 13:05, 10 March 2014 (UTC)[reply]
Yes it's real, New Scientist is a well-respected (if populist) science journal in the UK, and I note their footnote that the print article was originally titled "Pancreatic cancer's weak spot found". --TammyMoet (talk) 13:28, 10 March 2014 (UTC)[reply]
It may have been respectable at one time, but it has terrible journalistic standards these days, at least in areas where I have some expertise (medicine isn't one). I'm sure this research is real, but the realistic possibility of its turning into a cure for pancreatic cancer is probably much lower than the reporter wants it to seem. -- BenRG (talk) 21:11, 10 March 2014 (UTC)[reply]
New Scientist has never been respectable - it has always been what Scientific American has degenerated into, and even in its salad days, SciAm was just a tony popular-audience magazine, not a scientific journal. That being said, what would impress me would be a published paper on "pancreatic cancer's weak spot" in a peer-reviewed medical journal (my publication list includes papers in several such journals). Science or Nature would do; the New England Journal of Medicine would not, as it panders to medical politics; it is NOT a serious medical journal. Of course, a peer-reviewed article in Cancer or any other specialist medical journal where the peer review is apt to be searching and informed by clinical experience would be best. loupgarous (talk) 23:01, 11 March 2014 (UTC)[reply]
Sorry, I forgot I didn't post before - the excitement seems to trace back to mitocans such as alpha tocopheryl succinate (note: be sure to search for "mitocans" plural on PubMed - for some reason the site doesn't return the same results for the singular in this case!). I'd like to be hopeful, but the idea has been around for some time and seems a little short on miraculous results. Still... anything helps. Wnt (talk) 17:56, 12 March 2014 (UTC)[reply]
Finding academic reviews of Murry Salby's published work
Hi, this climatologist has published dozens of peer-reviewed articles, and two textbooks. I'm hoping to find guidance on locating reviews of his work, as well as how to structure presenting the information. Doe sit make sense to list all his peer reviewed published work. How do we note which ones are most notable and should definitely be talked about? Etc. Any help appreciated. Sportfan5000 (talk) 11:16, 10 March 2014 (UTC)[reply]
"How to structure presenting of the information" -- do you mean you plan on improving/extending his WP article, or is this for some other project? There will be different best practices depending on where you are presenting your work. One way to get a feel for the notability of an academic paper is it's citation count (available via google scholar), and perhaps the impact factor of the journal where it was published. I would not recommend listing all his published work. Our article says he has published over 100 articles (which is about right for a productive scientist of his age), and I doubt they are listed in full anywhere, except perhaps on his own curriculum vitae. As for reviews of his work, that is tricky. If you just google his book names, you get tons of blog posts and user reviews, which are not WP:RS. I suspect that e.g. nature_(magazine) or science news or science_(magazine) may have published some reliable reviews of his books when came out, but you'd probably have to have good online access through a university to search their archives. As for the articles, those don't usually have "reviews" written about them by experts. That is done privately by the journal before the article is published. Once it is published, the reader trusts that the editorial board of the journal has verified that the work is basically correct, viable, and of interest to the community. Some articles have "responses" published by other authors in the same (or next) issue of the journal, which are usually critiques of methods or conclusions. Basically, do not trust normal web searches for this guy. He is pretty unique, in that he is an actual atmospheric scientist who denies human-caused climate change, and that colors everything that you will see on google. (As far as I can tell, he is still not a specialist on climate change per se, rather being focused on upper atmospheric wave propagation for most of his early career.)SemanticMantis (talk) 14:37, 10 March 2014 (UTC)[reply]
Thank you for your thoughtful reply. This is only to help improve the WP article, I have no interest in the entire subject area outside of the article.
Looking at impact factor, it seems tied more to the journal than to the articles it contains so it may make more sense to note which of Salby's articles have the highest citation count.
I have not seen a curriculum vitae for Salby, and it doesn't seem like he promotes himself or his work, but has been doing some speaking engagements linked to global warming more recently.
Mid-2000s his entire work lab was dismantled, with varying disputes why, but the net effect is likely all his work in process was disrupted, so I'm trying to focus on accurately portraying his work from early 1980s-2005/6. Sportfan5000 (talk) 22:49, 10 March 2014 (UTC)[reply]
He jumped between at least a few different universities at the level of Associate prof. or higher. I guarantee you he was promoting his work in his field to achieve that! As for impact factor, think of that as a way of assessing the general prestige of a journal. Consider a made-up example: if he has two articles, each with 50 citations, the one in "Nature" will be more notable than the one in "Journal of Atmos. Sci", since "Nature" has a higher impact factor. One of the reasons that it is hard to get into Nature is that it covers all areas of science, so any particular article is seen by the editorial board as not only the top of its field, but so important that even non-specialists should know about it. As for the CV, I suspect you might find an old one online if you search long enough. But, not all academics post them to the public (I don't). It might be a long shot, but you could try to just ask him for it. If you are polite and say you want to use it to improve his WP article, he might go for it. Note the CV itself will not be a WP:RS, but it can point you towards sources that are. I really think the best thing in this case would be to look for "response" articles or "book review" blurbs in the major science rags. Finding the existence of such things is usually free/open, check at WP:REX if you need help getting access to full text. SemanticMantis (talk) 15:23, 11 March 2014 (UTC)[reply]
Remembering things only in a sequence
I can only recall, say, the 6th digit of my phone number by going through the first five. It's the same with say, the letter before Q in the alphabet. Is there a name for this kind of memory to distinguish from others? --129.215.47.59 (talk) 13:22, 10 March 2014 (UTC)[reply]
Sequence learning is about how we learn this way. Chunking (psychology) is used mostly with memory tasks -- how we group things together to remember them (in sequences, among other ways). The method of loci (an aspect of the art of memory) is an ancient technique for remembering things that involves a similar idea to chunking. I fear none of these will provide a great explanation for why you would be unable to remember things otherwise, though. --— Rhododendritestalk | 15:56, 10 March 2014 (UTC)[reply]
Our brains are wired for certain things. Learning a phone number could be important. Focusing on a specific digit does not seem so important. Of course, individual talents will vary, and practice and time can help. I can run through the calendar in my head and tell you how many days are in each month. But for many it may still be easier to use the old "30 days hath September" thing. ←Baseball BugsWhat's up, Doc?carrots→ 17:13, 10 March 2014 (UTC)[reply]
I know spelling works that way for me. For example, if asked to name countries which start with a certain letter, I likely will do much better than if asked to name nations which end in a certain letter. StuRat (talk) 17:25, 10 March 2014 (UTC)[reply]
discoveries of nasa space station
respected auditor
i have heared that a space shuttle or spaceship have discovered strange voices from space but scientists have not discovered that from where the voices are coming so please tell me about what have scintists discovered from space
As i am eager to get my answer — Preceding unsigned comment added by 119.154.28.74 (talk) 14:57, 10 March 2014 (UTC)[reply]
Wikipedia's lengthy Scientific research on the International Space Station article lists many of the experiments done on the ISS; all very worthy, but not spectacular, academic science. Since the end of the Space Shuttle program in 2011 the only manned spaceflights have been Russian Soyuz flights to the ISS. If anything was going to discover strange space voices it would be SETI, which hasn't yet. -- Finlay McWalterჷTalk21:35, 10 March 2014 (UTC)[reply]
When you think about it, this is impossible. Soundwaves can't travel through the vacuum of space - so these can really only have been radio waves or other electromagnetic signals...but all of those things are more easily detected by earthly telescopes and radio-telescopes - or the Hubble and other unmanned satellites - than with any of the instruments on the ISS and various shuttle missions. So it's completely impossible for those missions to have picked up anything we're not already aware of. So, this didn't happen - and whoever told you that it did has either misunderstood or been mis-informed. SteveBaker (talk) 02:41, 11 March 2014 (UTC)[reply]
Well, if ET is watching us from a stealth spaceship in low Earth orbit passing closely by one of our own spaceships then I suppose it could happen that their signal is too weak to be picked up from the surface, or maybe they are only transmitting home in a direction away from Earth. I haven't heard such a theory but it might be something a conspiracy theorist could accuse authorities of hiding. PrimeHunter (talk) 03:00, 11 March 2014 (UTC)[reply]
You need to consider all of the forces, and I think they did. E.g., the first equation in the solution expresses that the torques/moments around the left end of the bar add to zero: Ra × 0 + (−20N) × 0.4m + Rb × 1.0m = 0. -- BenRG (talk) 21:32, 10 March 2014 (UTC)[reply]
What they're doing is treating the left part of the bar, from 0 to x, as an object, and computing the moments acting directly on it around an axis perpendicular to the page and located somewhere on the right edge of the sub-bar at x (the vertical position doesn't matter). The moments are the two vertical forces on the left and the bending moment M, which is the integrated effect of the horizontal (normal) forces across the interface with the other sub-bar. M represents the torque from the 8N force as transmitted through the other sub-bar, so also including the 8N torque directly would double-count it. By Newton's third law the bending moment acting on the other sub-bar is −M, which gives a simpler formula M = 8N · (1.0m − x). I'm not sure why they used the more complicated one. -- BenRG (talk) 22:38, 10 March 2014 (UTC)[reply]
So can this problem be solved without breaking down into sub bars? I.e. By just considering forces on both sides of the point, in 1 equation? So, also considering the reaction force at B in that equation? 194.66.246.216 (talk) 09:29, 11 March 2014 (UTC)[reply]
Is this equation correct? M=12X-20(X-0.4)-(8(1-x))? If not, how would you find the bending moments across the beam, taking into account all forces? — Preceding unsigned comment added by 194.66.246.216 (talk) 09:34, 11 March 2014 (UTC)[reply]
The right hand side of your equation simplifies to zero, so it's incorrect. Think of pulling a block by a rope over a level surface against friction at constant speed. You pull on the rope with a force of (say) 10N; the rope pulls on the block with a force of 10N. It would never be correct to add those and get 20N. If you consider the rope and block as a single object, the second 10N force would be ignored because it is an internal force. If you consider the rope and block as separate objects, the two 10N forces would both be included in the calculations, but not added because they act on different objects.
You need to split the bar to compute M because that's built into its definition. From the perspective of the bar as a whole, the bending moment is a neglected internal force. The internal forces can be neglected because they all add to zero, which is more or less why your equation simplifies to M=0. -- BenRG (talk) 19:14, 11 March 2014 (UTC)[reply]
March 11
Ftc #104 ( Group Q's 1-8 )
To what extent are there competing schools of thought within the field of Fire Prevention? (Education, Engineering, Enforcement)
To what extent do experts in the field of Fire Prevention disagree about the answers they give to important questions?
What other fields deal with Fire Prevention and activites (from a different standpoint, perhaps)?
To what extent are there conflicting views about Fire Preventi in light of these different standpoints? To what extent, if at all, is the field of Fire Prevention properly called a science?
To what extent can questions asked in the field of Fire Prevention be answered definitively? To what extent are questions in this field matters of (arguable) judgment?
To what extent is there public pressure on professionals in the field of Fire Prevention to compromise their professional practice in light of public prejudice or vested interest?
What does the history of Fire Prevention tell you about the status of knowledge in the field? How old is the field? How common is controversy over fundamental terms, theories, and orientation?
All engineers use maths a lot of the time. Engineers spend a lot of time writing things that don't require maths - often it is in order to persuade someone else, or a group of others, about something. The people who are the target audience are often not highly numerate or highly mathematical people. When engineers do use maths it is often fairly basic algebra or geometry. Occasionally it is trigonometry. Sometimes it is even basic calculus. Engineers are expected to be competent in high-level maths because many of the more complex ideas they need to be conversant in, use high-level maths as part of their explanation. Engineers are rarely criticized for a lack of skill in maths, but engineers are regularly criticized for a lack of skills in written English. Dolphin(t)12:02, 11 March 2014 (UTC)[reply]
But surely someone has to do the detailed design calculations. Are you saying that other than detailed design engineers, most engineers don't use maths? Clover345 (talk) 12:26, 11 March 2014 (UTC)[reply]
I agree that "someone has to do the detailed design calculations." But your question is not "Do all the detailed design calculations have to be done by a civil engineer?" Your question is "Do all civil engineers use maths in their everyday work?" Of course, many civil engineers do things other than detailed design calculations. Dolphin(t)22:46, 11 March 2014 (UTC)[reply]
Surely, Engineers need to know the higher level maths, but it isn't like they do all of those calculations by hand on paper with a slide rule. They need to know the maths so they understand what they are doing, but most calculations today are done by machines, like calculators and computers. It doesn't absolve engineers from knowing exactly what they are asking the computers to do and why they are asking them to do it, but engineers are not required to do things which technology could do for them. --Jayron3212:34, 11 March 2014 (UTC)[reply]
Yes they do. It's also very important that they get it right. Whether it's calculating the camber of a curved road or how thick a dam wall must be, there is always maths involved. Like Jayron32 said - you need not know every formula out of your head but you do need to understand where to plug the variables in. 196.214.78.114 (talk) 12:40, 11 March 2014 (UTC)[reply]
Another example of using high-level maths is preparing examples using pencil, paper, and general purpose computer software (calculator, spreadsheet, Mathcad, Mathematica, or the like to verify that newly-written or unfamiliar computer software is working correctly, and that the engineer understands what the software is doing. Jc3s5h (talk) 17:17, 11 March 2014 (UTC)[reply]
As mentioned by Dolphin, communication skills are also important, Failure due to miscommunication can happen (especially if there are design changes) as happened in Hyatt Regency walkway collapse. One should understand the mathematics well enough to be able to explain it plainly (and the related physics, as Feynman did). — To refocus on the specific question: while some civil engineers might not need to use maths "everyday" in the sense of actually doing calculations, they are likely to "use math" in the sense of reading and understanding it. ~:71.20.250.51 (talk) 23:13, 11 March 2014 (UTC)[reply]
Speaking as an uncivil engineer in every meaning of that phrase, I use maths every day. Mostly it is hidden inside clever scripts that I run in matlab, but then I get to write those scripts as well. Examples of maths I use very frequently : Fourier analysis, analysis of well formed experiments (Taguchi), analysis of poorly formed experiments (usual ones), 3 dimensional geometry, analysis of complex spring mass damper systems, and matrices up the wazoo. Mechanical engineers are generally less reliant on tables and codes than civil engineers, and hence more reliant on day to day maths, partly because we can afford to make prototypes and break them, and partly because the codes and tables do not cover the wide range of products we design. Having said that I haven't solved a partial differential in decades, and only once since leaving uni have I had to solve a double integral by hand. Of course with Mathcad and the like available on every desktop actually solving a calculus problem by hand is more of a rite of passage than a useful exercise. Greglocock (talk) 23:51, 11 March 2014 (UTC)[reply]
What about civil engineers working in construction or for an infrastructure owner? Are they less likely to use maths than civil engineers working in design? Clover345 (talk) 09:43, 12 March 2014 (UTC)[reply]
Actually, if you look at the Tacoma Narrows Bridge (1940) article, it says that someone did the math -- "the most important theoretical advance in the bridge engineering field of the decade" -- and that's what convinced them to skimp on the structural elements in a way that made the collapse possible. Wnt (talk) 16:32, 12 March 2014 (UTC)[reply]
Well, the catch is that a mathematical model is never truly an accurate representation of a physical object. Certain phenomena ... such as vortices of wind ... might be omitted. The ways in which the model is deficient... come out in experiment. Wnt (talk) 20:34, 12 March 2014 (UTC)[reply]
Detecting debris from flight MH 370 from satellite pictures
I find it rather strange that the plane hasn't been found yet, it seems to me that it shouldn't be very difficult to find the debris of the plane using detailed satellite pictures from before and after the (presumed) crash by processing that using the enormous computing power that is available today. Or am I missing something here? Would there always be a lot of data from the pictures that would fit the general characteristics of the debris that one is seeking that wouldn't have anything to do with the crash? Count Iblis (talk) 16:18, 11 March 2014 (UTC)[reply]
DigitalGlobe has made images available and are asking for a crowd or Human flesh search engine to help them analyse these and look for possible points of interest. I can't say for sure that they aren't primarily a PR stunt and the crowd sourcing doesn't help much, although the various reports such as [3] do include quotes where it's implied it is difficult for their algorithms to differentiate wreckage from other stuff when using their data (i.e. including whatever limitations imposed by their satellite imaging capabilities).
China has also adjusted the operations of 10 of their satellites to assist in the search [4], although not surprising they haven't given any info I've seen on the the probability of their satellites finding something.
The US satellite capabilities would almost definitely be more than either of these and they must be using them to assist as well, but again, it's unlikely we would get that much info on the probabilities of their success.
It's worth remembering that even if the satellite imaging and processing power (remembering the ever increasing search area and the resolutions likely needed for success and this would need to be something they are able to spare in the midst of the ongoing Ukrainian crisis) is capable, you would need to have the existing algorithms available or be able to tweak whatever is available for that purpose in time.
This is a problem commonly experienced in photo reconnaissance. Although we now have ubercomputers (etc.) that are helpful, it still requires eyeballs to find stuff out in the middle of nowhere. Regarding the use of satellites, an analogy is trying to find missing car-keys using a microscope. ~:71.20.250.51 (talk) 18:48, 11 March 2014 (UTC)[reply]
There have already been false reports of plane debris, reported by human pilots flying over the sea. If humans can't easily tell the difference between plane debris and ordinary debris, a computer has no chance in hell. Remember that the Earth's surface is enormous compared to the size of an airplane, that garbage drifts into the ocean all the time, that airplanes and boats crisscross the surface constantly, and that most or all of the plane might be underwater (see Air France Flight 447, which took 2 years to find). ---Bowlhover (talk) 19:05, 11 March 2014 (UTC)[reply]
Regarding AF447, the searchers had retrieved definitive floating debris after only about 5 days. Yes, it took them 2 years to find where the fuselage had come to rest under more than 10,000 feet of water, but the floating debris was found after only a few days even though it was hundreds of miles from shore. Dragons flight (talk) 19:35, 11 March 2014 (UTC)[reply]
If the debris was in the water, it should be quite obvious, because much of it would float. It might be harder to find on land, as there's jungle in the area, and the plane could crash in the jungle with no obvious signs from above, as it would all be covered up by the jungle canopy. If nobody happened to be near the crash site, it could go hidden until somebody happens upon it.
The thing that seems odd to me is that they couldn't track it on radar to the crash site. Do they not have radar near where it disappeared ? Did it drop below the radar then fly many miles before crashing ? StuRat (talk) 20:31, 11 March 2014 (UTC)[reply]
Radar is little used in modern civilian aviation. It all works with transponders - instead of bouncing signals off the metal bodies of planes, air traffic control listens to active transmitters onboard aircraft. Radar degrades rapidly as function of distance, making it messy and unreliable, while transponders can transmit extra information such as speed, altitude, and identification. The transponder on MH370 stopped transmitting for an as yet unknown reason. A military radar happened to track the flight a bit longer, giving the latest best estimate of flight route. 88.112.50.121 (talk) 22:40, 11 March 2014 (UTC)[reply]
Indeed. Civilian (air traffic control) radar showed the aircraft dissappearing at a certain point. Military radar records showed that the plane turned at that point, descended to a low altitude, and continued flying another 500 km. So a catastrophic event didn't happen when it was lost to civilian radar. The transponder was turned off. Searching has been has been tailored to suit where it actually went (Malacca Straight), not just where it was when contact was lost (Gulf of Thailand). 121.215.154.87 (talk) 23:47, 11 March 2014 (UTC)[reply]
Radar and transponders complement each other. There are many obvious uses for radar, like tracking planes with transponders turned off or malfunctioning, enemy/terrorist aircraft, and other hazards to navigation like flocks of birds, storms, volcanic ash clouds, etc. So, using transponders alone is a very bad idea. StuRat (talk) 21:00, 12 March 2014 (UTC)[reply]
There's a lot of assumptions. First, the oddities: the transponder was off (or abruptly failed). Second, the bright orange black box will begin pinging if it's in salt water. Third, military radar differs from commercial radar on the track (military doesn't require transponders). It could be a) it didn't crash and landed somewhere or b) it crashed on land or c) it crashed where no one is looking. Only a few weeks before, a co-pilot took an aircraft to Switzerland for asylum. The cockpits are hardened so if the pilot/co-pilot locked the other out during a potty break, not much can be done. Personally, I'm thinking this was an attempt to take the plane so it could be used for nefarious purposes or suicide by plane (a la EgyptAir) by one of the pilots. I would be wondering if it had enough fuel to reach the eastern coast of Africa. For a catastrophic failure that shut off the transponder to occur without a debris field or the "black box" does not seem plausible. There would be items washing ashore. There are lots of speculative answers from catastrophic mechanical failure (of course the "lawyer experts" push this one on TV as Boeing has the deepest povkets), to a shoot down by China of a plane with improper transponder (a la KAL shootdown in 1980's), to a hijack suicide by pilot/co-pilot, to stolen airliner now on ground in some country, to a bomb on board. No single theory is better at this point as there is no data. The so-called "oil slick" was unrelated. The "door" was an unrelated piece of wood. And no black-box pinging away has been found. It wouldn't surprise me if terrorists had co-opted a pilot/co-pilot to steal a plane or if they just killed themselves with the plane. Nor would it surprise me if it were shot down as part of an air defense zone. Catastrophic failure seems the least likely option. A hole being blown in the hull near the transponder antennas would explain an emergency descent and no transponder but it's hard to reconcile an hours worth of flying with no radio unless all those antennas are in the same place (not likely, I hope). --DHeyward (talk) 08:46, 12 March 2014 (UTC)[reply]
My first reaction was that it could have been taken to a clandestine drug airstrip in the Golden Triangle or even a closed or bought-off airport so that the passengers and plane could be ransomed. And... the search seems gradually to be moving closer to Burma, which seems believable enough as a black hole. [5] But then ... where are the demands? I'd think it would take no more than one or two days to separate the hostages into little groups and scatter them in twenty places - unless the crooks are having some troublesome hostage negotiations among themselves. Let's hope that, Chronicles of Riddick style, one of them is left in custody moaning "I should have taken the money..." Wnt (talk) 17:52, 12 March 2014 (UTC)[reply]
You need a much longer runway to land one of these than some single-engine drug smuggling plane. I wonder what minimum length is needed if you don't mind wrecking the plane, say by running it into a shallow pond at the end of a short runway. Maybe ransom was the goal but the hijackers ended up crashing it in the jungle, and any surviving co-conspirators on the ground thought it safest to just walk away. StuRat (talk) 20:52, 12 March 2014 (UTC)[reply]
I was thinking something along those lines. Definitely if everything goes perfectly a plane doesn't need nearly the length of runway that is officially required, as has been discovered by several pilots landing on the wrong airstrip or even at the wrong airport in the U.S. recently. (The U.S. has perfected capitalism to the point where airplane pilots make the wages of fast food servers, and are literally eligible for food stamp assistance...) Wnt (talk) 02:57, 13 March 2014 (UTC)[reply]
I should note at this point that there is some indication that the OP was correct, and satellite scanning IS what actually worked, with floating debris right about where the wreckage was originally supposed to be. It leaves open some questions about why the Chinese took five days to find it in their satellite data, and why the U.S., despite all its appearance of surveillance omniscience, seems to have failed. Wnt (talk) 21:56, 12 March 2014 (UTC)[reply]
Grain of salt until they pull something from the water, for me. They also spotted a "door" and an oil slick but both were unrelated. The U.S. may have seen it as well, but given that disclosure of resolution of the detectors is likely to be classified, its use to find wreckage (not survivors) would probably not have been sanctioned. Wouldn't surprise me though if a U.S. warship started finding wreckage in its random search pattern. China may have held off announcing it for that reason as well (hoping he U.S. would disclose something that gave away a capability or not wanting to disclose their own). Or possibly China was conducting a military test of some sort that caused the plane crash. Or its just China being China. As for why a terrorists/drug cartel would want a plane, I can think of a few reasons including ransom, attacks, for study or PR gimmicks. And not to get too conspiracist, I think a simple cockpit window blowout and decompression followed by poor quick-donning mask response and procedure could knock the crew out in seconds. Still doesn' answer debris field but doesn't require a lot strange coincidences. Doesn't even require an explosion and at that altitude conciousness would be too brief to do anything but put on masks and the instruments would be a nightmare to see. --DHeyward (talk) 07:07, 13 March 2014 (UTC)[reply]
Well, China has now retracted the claim. I don't understand how the time of useful consciousness can be so short. Most people can hold their breath for a minute or longer, so how can the time of useful consciousness be a lot shorter than that? Count Iblis (talk) 00:31, 14 March 2014 (UTC)[reply]
The concentration of oxygen in arterial blood is directly proportional to the partial pressure of oxygen in the lungs. In air, the partial pressure of the oxygen is about 20% of the total pressure. When we hold our breath, the partial pressure of oxygen in the lungs begins at about 20% of atmospheric pressure and gradually falls to slightly less than that as blood absorbs some of the oxygen. (The thing that prevents us from holding our breath longer than a minute or so isn't lack of oxygen in the lungs, it is the increasing partial pressure of CO2. Our need to exhale, and our breathing rate, are determined by the partial pressure of CO2, not the partial pressure of O2.) At a pressure altitude of 35,000 feet, atmospheric pressure is only 24% of atmospheric pressure at ground level so when breathing air at 35,000 feet the partial pressure of oxygen is also only 24% of its ground level value - it is impossible to simulate that by holding the breath long enough to consume 76% of the oxygen because of the build-up of CO2. Also, have a look at Time of useful consciousness. Dolphin(t)02:01, 14 March 2014 (UTC)[reply]
Holding your breath would keep all the partial pressures the same. The problems is that your lungs can't maintain sea level pressure at 35,000 feet. They will burst. scuba diving works in reverse and the lungs are pressurized at depth. the danger of a deep dive is O2 poisoning because even though the partial pressure is still the same, the absoulut amount of O2 is much higher. Holding your breat during ascent will damage your lungs. In an explosive decompression of an airplanes, you will exhale, and the blood quickly loses it's saturated O2 from the pressure change and unconsciousness follows very quickly. The higher you go, the more dissolved O2 in the blood is removed as bubbles and the faster you lose consciousness. Your blood, almost instantly, loses it dissolved O2. You can see this when you open a soda bottle or champagne. Once the pressure is reduced with opening, the dissolved CO2 comes out of solution and fizzes. --DHeyward (talk) 03:28, 14 March 2014 (UTC)[reply]
P.S. one of the reasons I like the decompression as a theory is that, at least when I was being taught, whenever changing transponder frequencies was to put it in standby until all the numbers are entered so the hijack/emergency codes weren't accidentally sent out. That's not necessary for digital FMS systems like they use now but old habits die hard. If they put the xpndr in standby while fiddling with FMS, xpndr and O2 with a 500mph wind in the cockpit, it's not unthinkable that they passed out with a mid altitude heading and a xpndr in standby and never made it to putting on O2 masks as they raced for a breathable altitude. they then simply flew until their fuel exhausted. --DHeyward (talk) 09:11, 14 March 2014 (UTC)[reply]
It's worth remembering that most of the vessels and planes doing the searching are from various countries' militaries, and anything they find will first have to go through the military security channels of those countries. We won't get full details of what is found, and how it was found. American and Chinese (and other countries') satellites no doubt have greater capabilities than they would want to publicly share. What we might see is an American ship searching in a new "broader" search area just happening to sail right where some genuine debris is. HiLo48 (talk) 00:50, 14 March 2014 (UTC)[reply]
Disappeared from radar ?
There are two obvious ways something can disappear from radar. Which applies to this plane ?
1) Drops below the radar's detection altitude (at that distance).
There are in-between scenarios that depend on the surveillance method. Military primary surveillance radar won't care about the plane (though it may pick up IFF encrypted transmissions as well as civilian transponder codes). Secondary surveillance radar sweeps the sky but the aircraft squawks flight data. This airplane most likely had ADS-B, Mode S and pilot/controller datalinks with backups for each (backup hardware, antennas and power supplies.) "Disappearing from radar" then becomes a relative term. 'Which radar?' is probably the proper question. If the airplane switched off Mode C/S, ADS-B and CPDLC but still flew for an hour, something very strange happened. The ELT can be activated manually and deactivating the transponder is a deliberate act. It's not clear to me that civilian primary radar was necessarily available in that region and the "dropping off of radar" was really a lack of transponder interrogations. Other ADS-B equipped planes (or warships) in the area may also have pertinent logs. It's a tricky problem with a primary radar signature and no transponder because everything else has to be ruled out. --DHeyward (talk) 06:23, 13 March 2014 (UTC)[reply]
About the radar issue, I want to clarify that AFAIK the current (and it's actually been like this for a while, since before my reply above) public understanding is that the something was tracked on the radar, it's just unclear if it was the flight. I presume this means there wasn't a continous track of this object from the last known position of MH370 but I don't think this has been publicly revealed. (As I think was mentioned above, it's worth remembering that this was fairly far from land and so it may not be that surprising if it wasn't properly tracked when the transponder stopped transmitting. I suspect the equipement the various Malaysian authorities have isn't that sophisticated too.) Of course if it did travel west far off course, radar and other information may be available from other sources who weren't perhaps looking that closely initially.
It's also worth considering that we don't really know what the authorities know and think privately (not just the Malaysians but all those involved). There has been a lot of criticism of the Malaysian authorities handling of the search, but how much of this genuine mishandling and insufficient sharing; and how much of it relates to the nature of the disappearance, the fact the media don't really have much else to do, and differing views on what to share (when sharing it publicly may not have made a difference to the search) is unclear to me.
I know there has been some suggestion that the Vietnamese and Chinese authorities have also complained about not receiving enough information and confusion from what they did receive. In the Chinese case, since there is obvious anger from their citizens it's useful for them to blame someone else rather than just saying 'no one knows, it is confusing, and there's not much anyone can do'. The Vietnamese don't really have that issue. But it's not totally clear to me how much of the recent fuss is because they feel they haven't received enough information. And how much of it is that they've already undertaken an extensive search near their territory and with so many others involved and with large swaths of other areas where it could be, they're not sure if there's much point them continuing at such a high level.
It's the two different radar systems. Once the transponder goes off, the secondary civilian systems are blind. The systems get a blip but no identification. Piecing together that the unidentified military blip is the same object on a separate civilian radar that went dark is not as easy considering it's different countries with different systems. the oddest piece that I would be interested in is the engine data that was apparently data linked to Rolls Royce for 5 hours after the transponders went dead. How or if that is possible would seem pretty important. --DHeyward (talk) 08:59, 14 March 2014 (UTC)[reply]
Organising colours
I have many reels of sewing thread I'd like to organise according to its colour. I have trays suited to this purpose enabling four rows and about 15 columns. What question should I ask myself about the colour of the thread to determine where it goes? I'm trying to use MS Paint's colour selector as a guide. I'm not sure whether that will help or hinder me. ----SeansPotato Business18:45, 11 March 2014 (UTC)[reply]
Caution:staring at this might cause a '60s flashback Each color in a computer graphics program such as MS Paint is distinguished by 3 values of the primaries Red, Green and Blue added together. It's not obvious how the implied 3-dimensional color space can help you plan a 2-dimensional (rows and columns) layout for coloured threads. Here is a possible arrangement where colors are in rainbow order vertically and decrease in saturation going from left to right. 84.209.89.214 (talk) 19:49, 11 March 2014 (UTC)[reply]
One problem with sorting real-world colors using RGB, is that this scheme is intended for computer displays, and can be counter-intuitive. For example: What do you get if you mix red and green? If you try [R=255, G=255, B=0] (max red and green, no blue) what you get may surprize you. [Hover cursor here for answer] ~E:71.20.250.51 (talk) 20:30, 11 March 2014 (UTC)[reply]
It looks like it's a basic HTML attribute title, which can be applied to various elements (like this and this). It's possible to turn off the special formatting (border-bottom:0px;cursor:default;) and even to include the result of Some Lua script in the mouseover, but I haven't figured a way to style the mouseover text (per [6]) without having access to the site CSS (or using a personal CSS for me only). Wnt (talk) 12:56, 12 March 2014 (UTC)[reply]
I am a male non meat eater i.e lacto-ovo-vegetarian and a fitness freak. I feel soya has almost 50% protein and very less fat and I just love it. But I heard that Soy contains large amounts of biologically active compounds called isoflavones, which function as phytoestrogens… that is, plant-based compounds that can activate estrogen receptors in the human body. Thus it can decrease my testosterone levels! Is it true ?? How much soy is optimum for daily consumption ? — Preceding unsigned comment added by 119.235.54.187 (talk) 07:54, 12 March 2014 (UTC)[reply]
Note that estrogenic chemicals are everywhere. They may also be in milk products and in plastics and the linings of cans. As far as non-estrogenic protein sources for vegetarians; nuts, peanuts, seeds, and beans are all good, and fish and eggs are also good for those who are allowed to eat them. StuRat (talk) 21:14, 12 March 2014 (UTC)[reply]
This might seem like a question more suited to the computing ref desk but since it's a bit science-y I thought it might get better answers here. I have capacitor in an LCD monitor that has started hissing, this is apprently quite common in LCD monitor and is due to a bad capacitor. All solutions on the internet seem to suggest either a) replace the monitor (I'd rather not), b) Turn up/down brightness (turning up makes it worse, turning it all the way down gets rid of it, but sort of defeats the point since the monitor isn't very useable.). The monitor is out of warranty and old enough that sending it for repairs might be difficult (about 8 years old - although rarely used).
I thought I could have a go at coating said capacitor in some form of non conductive heat resistant resin to keep the noise down. I figure I may as well try if the only other solution is to replace the monitor. What resin could I use? I was thinking something like the stuff they put on circuit boards to keep components from shorting and in place, it's usually brownish or black. I realise this is fairly dangerous and would take nessecary precautions and obviously not do it with the monitor plugged in. 80.254.147.164 (talk) 10:16, 12 March 2014 (UTC)[reply]
DANGER! You do not say what kind of capacitor it is. If it is an electrolytic (one marked to indicate + & - polarity), NEVER EVER enclose it in epoxy resin, and only use another type of resin if you DEFINITELY know what you are doing. The reason is that such capacitors are designed to vent when overstressed. Enclosing it in resin is the same as making any sort of pressure vessel - a circuit fault may make it explode. And a capacitor that makes any noise you can hear loud ennough to be anoyed by it is an overloaded capacitor. The hissing indicates possible arcing inside - if so failure is imminent. So coating it is resin is waste of time anyway.
To ask a question like this indicates you are not electronics trained. DO NOT work on AC voltage powered euipment unless you are qualified. Scrap the monitor or take it to a qualified repair shop.
^ I can not stress how much I agree with the above statement. Do not attempt this yourself. Your fix will make it dangerous, and your lack of knowledge could kill you (no offense). Find somebody local that can do the repair for you, and simply get the capacitor replaced. The one you have is about to blow, and I mean blow.217.158.236.14 (talk) 11:22, 12 March 2014 (UTC)[reply]
If the fault is confined to the capacitor, and you can find an old-fashioned TV repair shop, then the cost might be quite small. The modern repair process is to send the equipment away to a specialist central repair shop and the cost of transport and administration usually exceeds the cost of repair. Dbfirs17:48, 12 March 2014 (UTC)[reply]
Yea, I noticed that, too. My guess is that he's playing it safe, by allowing for either the giant impact hypothesis or the Moon just coalescing from smaller objects. StuRat (talk) 21:18, 12 March 2014 (UTC)[reply]
Or, it's the first episode and they'll get into greater detail later. There's 13 episodes, and they've broadcast 1. --Jayron3222:44, 12 March 2014 (UTC)[reply]
The script for the first episode sounded a lot like the script for Sagan's first episode. It would be interesting to run the shows side by side and see where they differ. For example, in the new series the animations of the historic figures looked like they were done by the guys who created Clutch Cargo. ←Baseball BugsWhat's up, Doc?carrots→ 23:00, 12 March 2014 (UTC)[reply]
What did Carl Sagan have to say about the Moon's formation ? If he didn't agree with the giant impact hypothesis, perhaps Neil doesn't want to contradict him. StuRat (talk) 00:28, 13 March 2014 (UTC)[reply]
I don't remember what Sagan said in the 1980 version, but the great impact hypothesis might not have been the dominant theory at the time, whereas today I think it is. Bubba73You talkin' to me?02:19, 13 March 2014 (UTC)[reply]
Of note, regarding the animation, is that Seth MacFarlane is an executive producer of the series and provided much of the financial backing and business connections to get it made. He provided the voice for Giordano Bruno himself and probably had a lot to do with the animation and creative decisions thereof. --Jayron3223:08, 12 March 2014 (UTC)[reply]
What is the advantage of the former? You always have to rewind it completely to use it again. Although a double reel would need a bigger cartridge, the cartridge is the cheap part of the cassette tape. That would still be an issue in the case of big reels (like movies in 35-millimeter film), but why do Linear Tape-Open, for example, was designed with just one? That's contrary to VHS, Betamax, and audio cassettes. OsmanRF34 (talk) 22:47, 12 March 2014 (UTC)[reply]
(For those unfamiliar with this topic, the single reel system uses a take-up reel on the player.) The issue probably is size, but not because a larger cassette is more expensive, but rather because it's less portable. StuRat (talk) 00:24, 13 March 2014 (UTC)[reply]
Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. --Jayron3223:45, 12 March 2014 (UTC)[reply]
In that case there seems to be something missing. You seem to have knowledge that there are controversies regarding this topic. Please tell us why you think that there are. StuRat (talk) 00:14, 13 March 2014 (UTC)[reply]
I've taken the liberty of wikilinking the term in the original question. Sometimes when you do that, you find your question answers itself, but in this case it's not clear that the article is sufficient. Wnt (talk) 03:00, 13 March 2014 (UTC)[reply]
March 13
Bubbles
Hi.
While doing various projects using water I have noticed that when pouring water from a hose that some times a small droplet of water (about 2 or 3 mm diameter) rolls across the surface of the pool of water and disappears.
The other is when filling a fish tank, I observed a bubble (same size as the first droplet described) which didn't rush to the surface like an air filled bubble, but stayed circulating in the current of the flow from the hose for a few seconds before disappearing. My question is, is this a bubble of water, under water, the same as it is to have a bubble of air in the air?
and the former bubble, a bubble of water on water in the air? Cheers. Gary — Preceding unsigned comment added by Garycurious (talk • contribs) 02:20, 13 March 2014 (UTC)[reply]
On the water droplet, I've observed something similar, that a drop falling into a tub sometimes will roll around for a bit before it collapses. I assume this has to do with it's momentum (spin in particular) being more than the adhesion force that wants the water droplet to stick to the tub. Your water droplet case would be similar, but there the momentum would be greater than the cohesion force of water wanting to stick to water. There could also be a similarity with rock skipping, where the momentum of the rock causes it to bounce off the water.
As for the second case, which I assume to be an air bubble, was the water stream pointed downward ? If so, the tendency of the bubble to want to float to the top is fought by the water stream pushing it down. If there's less downward force in the center of the stream, then a stable spot may exist there for the air bubble. StuRat (talk) 02:29, 13 March 2014 (UTC)[reply]
Tree identification
What are these trees (in San Diego, California, USA?)
Good call, although the bark on a Torrey pine should be "red-brown to purple-red"[9] and I would have said that bark on the first image above is grey (or gray) although it seems to get red-brown further up. Looking at the second image, the needles seem to me to be in bundles of two or three. The Coulter pine has needles "3 per fascicle, slightly spreading, not drooping, mostly ascending in a brush"[10] while the Torrey pine has "mostly 5 per fascicle". Perhaps if User:69.108 would be so kind as to go back and see if the needles are in threes or fives, we'll have a definite answer. Alansplodge (talk) 16:27, 13 March 2014 (UTC)[reply]
When I saw how the ammo is arranged in Leopard 2 , Leclerc and Black Panther tanks , I wondered if is it safe to put this large amount of ammo in the front of the tank - even if the frontal armor is the thickest - is there a blowout panel for this ammo ? if not , is there big difference between western tanks and Russian tanks in terms of safety or in terms of exposure of ammo to cook off ? Tank Designer (talk) 08:56, 13 March 2014 (UTC)[reply]
So I can say there is not a completely safe tank in the whole world - in terms of ammo storage - except the M1Abrams , but the Abrams is not practical due to its high maintenance costs and its high fuel consumption Tank Designer (talk) 10:51, 13 March 2014 (UTC) . — Preceding unsigned comment added by Tank Designer (talk • contribs) 10:50, 13 March 2014 (UTC)[reply]
I think you're right that there isn't a completely safe tank - but some are safer than others. The same forum has Ammo stowage, a summary which lists most modern tanks and their arrangements. Note that forums are not regarded as a reliable source for the purpose of Wikipedia articles. Our article on the Challenger 2 states that it is "one of the most heavily armoured and best protected tanks in the world" and compares favourably with the M1 in terms of fuel consumption reliability and IR heat signature, but then I'm probably a bit biased. Alansplodge (talk) 11:50, 13 March 2014 (UTC)[reply]
I agree with you that Challenger 2 is the best protected tank in the world , and also its gun has the longest range in the world Tank Designer (talk) 12:46, 13 March 2014 (UTC)
I can say that Challenger 2 is the best tank in the world if it was a little bit faster Tank Designer (talk) 12:50, 13 March 2014 (UTC)[reply]
I think the speed issue put the European buyers off the Challenger 2, plus the fact that many of them were already operating the Leopard 1 and that the bigger production run made the Leopard 2 a lot cheaper. Alansplodge (talk) 16:54, 13 March 2014 (UTC)[reply]
Is there any example of any of these tanks suffering such an ammunition cook-off? If not, then perhaps they are all good enough. Rmhermen (talk) 22:02, 13 March 2014 (UTC)[reply]
According to our article on the Leopard 2, a Danish driver was killed in one by an IED in Afghanistan. A British Challenger 2 was destroyed during the 2003 Invasion of Iraq in a "friendly fire" incident, when a shell from another Challenger hit the commander's hatch showering "hot fragments into the turret, killing two crew members. The strike caused a fire that eventually led to an explosion of the stowed ammunition, destroying the tank. It remains the only Challenger 2 to be completely destroyed on operations". Alansplodge (talk) 09:29, 14 March 2014 (UTC)[reply]
A Google search yielded nothing, rather complicated by the existence of something called "St Lawrence lime stone". Anyway, the Common Lime, Tilia x europea is (as the name suggests) far and away the most common planted lime in England. A recognition feature is that the trunk is "burred and densely sprout-infested at the base", according to the estimable Alan Mitchell in his Field Guide to the Trees of Britain and Northern Europe (p. 359), a book of biblical authority in my opinion. He says that the hybrid is "of natural origin" and "possibly native". I can see lots of burrs on the photos of the tree; I suspect that the groundsman would have kept the sprouts at bay. That's the best I can do, hopefully, the sages of the Kent Field Club will produce a definitive answer. Alansplodge (talk) 15:48, 13 March 2014 (UTC)[reply]
This webpage claims that it's a Small-Leafed Lime (Tilia cordata), however, I'm dubious. Mr Mitchell says that "the dense yellowish-green crowns of old [small-leafed lime] trees can be identified at a distance". I can't see yellow in any of the pictures. Alansplodge (talk) 15:58, 13 March 2014 (UTC)[reply]
No scientific body of national or international standing
As of 2007, when the American Association of Petroleum Geologists released a revised statement, no scientific body of national or international standing rejected the findings of human-induced effects on climate change.
The references are quite old...seven years on. Is there some way we can update and/or verify this claim?
Note that by "scientific bodies " what is meant are organizations like e.g. the American Physical Society. These are bodies that publish the leading peer reviewed journals that most scientist in the field publish there results in. In theory, anyone could start some obscure organization and call that a "scientific body", but that's not relevant here. Count Iblis (talk) 13:50, 13 March 2014 (UTC)[reply]
I have removed the tag. If you know better then fix the text or put something on the talk page. Just because something is a few years old doesn't mean it has changed since. Dmcq (talk) 14:31, 13 March 2014 (UTC)[reply]
Large scale disasters
In many large scale disasters such as the 2011 Tohoku earthquake in Japan, the response seems to mainly involve military and aid agencies (both international and national). So what do the national emergency services do in these cases? 194.66.246.93 (talk) 13:52, 13 March 2014 (UTC)[reply]
The premise of your question is entirely false - normal civil agencies like police and fire services are fully employed in these cases. Indeed, the definition of "national emergency" is pretty much that set of events where the normal civil response function is overwhelmed and must call out for assistance from other regions and services. -- Finlay McWalterჷTalk13:58, 13 March 2014 (UTC)[reply]
To expand on Finlay McWalter's answer, the purpose of "national emergency services", like FEMA in the U.S. or other similar government agencies, is NOT to perform the functions that everyday emergency-management services like police, fire, ambulance, rescue, military, etc. perform. It's not like there's a declared national emergency, and the local services stop functioning to let FEMA (or similar) agency do everything. Instead, what those services are supposed to do is to coordinate the response from various agencies when the local agencies are overwhelmed, and extra support needs to be brought in. For example, (and I'm using a U.S. example because I'm only familiar with it) let's say that Los Angeles is hit by a particularly bad earthquake. Very quickly, local emergency response units are going to become overwhelmed. There aren't enough ambulances to ferry all the injured to hospitals, not enough firefighters to put out blazes, not enough police to keep people calm and prevent looting and opportunity crime, not enough local charities to feed the displaced. Now, very quickly, hundreds and thousands of other people will start going to LA to help out. Doctors, paramedics, charity groups, etc, all show up saying "How can we help?" The deal is, NONE of these people knows where they are needs, knows anything about local geography, they're just useless extra bodies taking up space unless someone tells them "You go here and help do this!" etc. The "national emergency service" organizations like FEMA are supposed to provide that coordination and organization. They assess what is needed, and tell people where to go provide for those needs. That's what they do. They don't actually have the personnel on hand to provide the services themselves (that'd be a waste, keeping thousands of people waiting on payroll doing nothing until that rare emergency occurs). Instead, they have people on payroll who are experts in organizing others, so when the doctors and firefighters and regular folks just wanting to pitch in and help start showing up from all over, someone knows where to send them and help them be effective. --Jayron3214:50, 13 March 2014 (UTC)[reply]
Note that the National Guard is supposed to be (original intent of the Constitution) under control of individual state's Governors. But... According to Article I, Section 8; Clause 15, the United States Congress is given the power to pass laws for "calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions." Nevertheless, Governors often turn to their National Guard units for help during large-scale local emergencies. ~:71.20.250.51 (talk) 22:17, 13 March 2014 (UTC)[reply]
Structures with different values of g to 9.81 in load calculations
Assuming a structure is on earth, is g always 9.81, unless dynamic loads change this as may be the case with vehicles as a result of g forces generated from acceleration? Clover345 (talk) 15:12, 13 March 2014 (UTC)[reply]
There is a small variation in the value of g, due to many factors:
1) Your altitude or distance below the ground or sea.
2) The density of the material underneath and above you.
3) (Apparent) centrifugal force at the equator reduces g somewhat there relative to the poles.
Also note that, due to buoyancy, objects underwater behave, in some ways, as if they are under a lesser g force. If the material is the same density as water, it's something like being in 0 g, while less dense materials behave as if under a negative g force. This effect can also happen underground, if below the water table, or even above the water table, where the density of the surrounding soil provides a buoyancy effect (buried tires can "float" to the surface). And lighter-than-air craft also have an apparent negative g force in air. (Technically any object in air behaves as if in a slight reduced g force, but the effect is negligible for most objects, due to their much greater density than air.) StuRat (talk) 15:29, 13 March 2014 (UTC)[reply]
True, but the effects of the sun and moon are negligible compared with the 0.7% variation in the earth's gravity over the surface, even at sea level (with a further variation with altitude, as mentioned by StuRat above). The main contributions to the variation in "g" are the shape of the earth (an oblate spheroid), and the centrifugal effect that is greatest at the equator. "g" at sea level varies from about 9.76 to about 9.83. Forces due to other accelerations are sometimes called "g forces", by analogy with the (almost constant) "g" of gravity. Dbfirs07:33, 14 March 2014 (UTC)[reply]
Groundnut limit
Can I consume 200 grams groundnut (partially roasted) everyday for gaining 50 grams of protein from it ? Will it affect the body adversely ?? — Preceding unsigned comment added by 119.235.54.187 (talk) 15:34, 13 March 2014 (UTC)[reply]
The general health recommendation is to consume a variety of foods, not just a few. While I'm not aware of any toxin in groundnuts you need to avoid, even a slight nut allergy to something like peanuts could become serious if you consume those quantities. Also, if those nuts are salted, you may get a sodium overdose. Then there's concern that you may not get other nutrients that you would get if you consumed other sources of protein, such as vitamin B-12 and dietary iron. Finally, you are likely to get sick of them and fail to maintain such a diet. StuRat (talk) 15:46, 13 March 2014 (UTC)[reply]
We're not supposed to give medical advice here, and without seeing your entire diet and medical history we can't speculate on the risks and benefits of eating peanuts. We can, of course, note that peanuts are sold by the pound and that many of us personally enjoy them by the pound, though some may say we have been affected adversely, at least as far as body weight is concerned. :) Wnt (talk) 15:53, 13 March 2014 (UTC)[reply]
Nutritional advice is not medical advice, if it was, any author of a nutritional book would be arrested for practicing medicine without a license. StuRat (talk) 15:59, 13 March 2014 (UTC)[reply]
Well, my point is that we don't know (whether for ideological or personal medical reasons) a person has a need for more protein or is already receiving more than they need, and the same is true of calories, to a degree even salt (though it's implausible anyone in an industrialized country really needs the amount peanuts are salted with due to a scarcity of it in their other dietary items). Wnt (talk) 16:07, 13 March 2014 (UTC)[reply]
Presuming "groundnuts" means peanuts, they are pretty nutritious. The main concern would be that 200 grams of peanuts contain almost 100 grams of fat, which already exceeds the recommended daily intake even if everything else you eat is fat-free. Looie496 (talk) 16:04, 13 March 2014 (UTC)[reply]
As far as the 50 g of protein a day, I believe the recommendation by the FDA was 55 g per day, before they stopped making any recommendation. Also note that you can get get too much protein, which puts a strain on the kidneys. (This has inspired my following Q.) StuRat (talk) 16:23, 13 March 2014 (UTC)[reply]
I would like to clarify that I don't have any allergy to peanuts! I also don't eat them salted and in fact combine them with jaggery and eat.I am basically a fitness freak who loves burning fat so the 100 grams fat will be too much for me ?? — Preceding unsigned comment added by 119.235.54.187 (talk) 16:38, 13 March 2014 (UTC)[reply]
Jaggery is mostly sugar, and consuming large amounts of sugar is unwise, especially all at once, as it can cause a sugar spike and then sugar crash. (During the sugar spike the body produces insulin, which converts the sugar into fat on you body, causing the blood sugar to plummet.) Exercising after eating that will certainly help, though, as will eating the nuts in small quantities spread throughout the day. Also avoid sugary drinks, but get plenty of water (I drink unsweetened herbal tea, myself). And brush your teeth frequently to avoid cavities from all that sugar. StuRat (talk) 17:36, 13 March 2014 (UTC)[reply]
A little common sense is in order here. Peanuts & jaggery sounds like a yummy treat. As with most good things: some is good; too much is bad. Note that happy people tend to live longer.[citation needed] Happiness is good for you! ~Cheers, ~:71.20.250.51 (talk) 17:56, 13 March 2014 (UTC)[reply]
Nutritional web site ?
Is there a web site which lists the current scientific consensus of the minimum and maximum recommendations each person should consume daily for each nutrient ? Some will only have a minimum, and they might need to ask your gender, age and weight to make the recommendation (and if pregnant). FDA recommendations seem woefully out of date and absent entirely for many key nutrients. StuRat (talk) 16:23, 13 March 2014 (UTC)[reply]
And what form of radiation do you mean ? Radon gas liberated by tremors or quakes could damage human health, but you'd need to be exposed to it over a long time period. StuRat (talk) 17:47, 13 March 2014 (UTC)[reply]
Distances between moons, planets, and stars
Is the commonly given measure of distances between them from surface to surface or from centre to centre? (e.g. Moon-Earth 384 399 km) Th4n3r (talk) 23:08, 13 March 2014 (UTC)[reply]
"centre to centre" is correct. This is discussed in our article on apsides: "the apsis technically refers to the distance measured between the centers of mass of the central and orbiting body". RomanSpa (talk) 00:40, 14 March 2014 (UTC)[reply]
No. See [13] and [14] for a few examples. No sites I can find note any nutritive value for it at all. It should also be noted that food does not contain calories. It provides them. Calories are a measure of food energy. Most substances don't provide any food energy; roughly speaking only a few classes of compounds can be broken down by your body to provide you with net energy, the article food energy notes what those are. Part of the problem is the use of the word polyol which really refers to two (essentially) unrelated classes of compounds. Polyol can refer to sugar alcohols, which do provide food energy, but it can also refer to polymers made from alcohol monomer units. Polyethylene glycol is this kind of polyol, which is unrelated to sugar alcohols. --Jayron3203:15, 14 March 2014 (UTC)[reply]
It sounds like some unsung heroes of science (I mean, studying diarrhea...) believe that PEG is not metabolized by the human or bacterial components of the digestive system. [15] I would be suspicious that if someone made a long-term habit of eating large amounts of it that eventually the bacteria would find a way, but that's not discussed here, hopefully due to lack of experimental data! Wnt (talk) 03:20, 14 March 2014 (UTC)[reply]
(edit conflict) Regarding that, Wnt, PEG has medicinal use for the purpose of whole bowel irrigation, often in preparation for a colonoscopy. In basic terms, it cleans you out entirely so that they can send cameras up to take a peak. Diarrhea is basically what it is intended to do to you, "whole bowel irrigation" is a polite term for "medically induced diarrhea". --Jayron3203:30, 14 March 2014 (UTC)[reply]
(edit conflict)My understanding is that polyethylene glycol is not metabolized by the human body, and thus cannot be stored or provide calories. There is research on actually injecting animals with PEG directly into the blood stream or spine, which mention that it "dissolves away". Not sure how that actually happens though [17]. But theory goes it should not enter your circulation from the gastrointestinal tract. So yeah, if your body can't absorb it, and it can't break it down, no calories. Someguy1221 (talk) 03:24, 14 March 2014 (UTC)[reply]
Freezing water
Lets say I have a normal bucket of water and it's lukewarm. I also have an icecube that has been cooled all the way to -100 celsius. Would the bucket freeze if I dropped that icecube into it? What if the icecube is like 200 or 500 degrees negative celsius?
Please do your own homework.
!["re-inventing the [color] wheel"](/wiki/File:The_Shark_Wheel_design_is_fast_on_hard_surfaces_and_goes_over_varying_terrain.png){kind=link}
