Wikipedia:Reference desk/Archives/Science/2015 March 10

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

March 10

Can it be an isotope with less neutrons than the number of its atom?

149.78.32.22 (talk) 03:27, 10 March 2015 (UTC)

Hydrogen is an isotope with zero neutrons, and therefore less than the number of its atom, so yes. --OuroborosCobra (talk) 03:32, 10 March 2015 (UTC)

Anything with n < Z at Table of nuclides (complete). PrimeHunter (talk) 03:40, 10 March 2015 (UTC)

So, is there only one isotope with less neutrons comparing to the number of its atom? (hydrogen)? 149.78.32.22 (talk) 03:48, 10 March 2015 (UTC)

No, there are many. You can do your own research by clicking any of the elements in the table below, and searching for ones with less neutrons than protons. --Jayron32 04:01, 10 March 2015 (UTC)

Hydrogen 1 is the only "dominant" isotope.

Helium 3 is the most famous; it's an excellent fusion fuel with few hazardous byproducts (for example no neutrons, duh). ¹H and ³He are the only stable ones.

⁷Be, ¹⁰C, ¹¹C, ¹³N, ¹⁴O, ¹⁵O, ¹⁷F each have half-life of minutes or more. - ¡Ouch! (^{hurt me} / _{more pain}) 10:15, 10 March 2015 (UTC)

Isotope half-lives.

See also Neutron-proton ratio. Simply eyeballing the adjoining graph, it would seem that every element with atomic number <47 has at least one known isotope with fewer neutrons than protons. (Recommend that you double check that with the source database directly, if you intend to cite this as a fact anywhere.) Abecedare (talk) 04:48, 11 March 2015 (UTC)

Looks like the last such isotope known is ⁹⁹Sn, per isotopes of tin. Double sharp (talk) 12:57, 22 September 2015 (UTC)

It is nevertheless true that ¹H and ³He are the only stable such isotopes, and ¹H is the only one that is the most common isotope of its element. Double sharp (talk) 12:58, 22 September 2015 (UTC)

ICT 100 invented by Feriz Delkic

Hi My name is Almira P. I recently met person by the name Feriz Delkic who 25 yrs ago invented ceramic coating ICT 100. Used by Nasa and USA Navy . When ceramic coating is applied can endure high temperatures over 1800 F He lives in Ponte Vedra beach FL. I came on your web to find out more about this man and I was surprised not to find anything ??? — Preceding unsigned comment added by 2602:306:3054:45D0:A11E:58FD:7835:DA5C (talk) 08:18, 10 March 2015 (UTC)

Hi Almira P. As I understand it, Wikipedia is missing a lot of articles it might have. In this case, the problem may well be that no newspapers/books/TV shows/etc have written about Feriz Delkic. Wikipedia's rule is to wait until this happens, then report on what the journalists said. 184.147.127.2 (talk) 15:00, 10 March 2015 (UTC)

If you google his name the only information that comes up about him is that he is the President of Delkich International Technical Ceramics Inc. Unfortunately that's not enough information for an article, for which we need information from wp:reliable sources to establish that he is notable enough for an article (see: wp:notability). Richerman (talk) 15:33, 10 March 2015 (UTC)

Their website is here, and the product in question is ITC100-HT. WP:CORP is our relevant notability guideline. See Ceramic engineering for our article on the subject. Tevildo (talk) 00:39, 11 March 2015 (UTC)

Our standards for notability often seem rather harsh - but we need to produce evidence for everything we say about someone. If we were to create an article about this guy - the only things we'd be able to say are things that are published out there for people to refer to. In this case, it seems that there simply isn't enough written about him to support a reasonable article. We can't work from anecdotes from people who knew him or other hearsay information. Worse still, we have even stricter rules about biographies of living people (enshrined in WP:BLP) - because mistakes in articles like that can be very damaging and potentially result in well-justified law suits. I suppose it's unfortunate that a lot of very worthy, useful, clever people never get written about...but that's life. I was one of the team of four guys who made the first CD-ROM - do you see me mentioned anywhere in conjunction with that? Nope - and (at least in part) that's because we worked for a big multinational corporation who didn't go around trumpeting the names of their workers in print. Layered on top of that are our notability criteria. We can't possibly have articles about every human being who ever lived - so we have to have a cut-off beyond which someone simply isn't sufficiently notable to be worth writing about. SteveBaker (talk) 15:07, 11 March 2015 (UTC)

dinosaur

What is the last discovered dinosaur genus?--213.26.205.146 (talk) 12:22, 10 March 2015 (UTC)

Hard to say for certain. I used Wikipedia's category system to try to figure this out, and came across Category:Fossil taxa described in 2015. According to that category, only one dinosaur is listed (the rest come from other branches of the Tree of Life). That dinosaur is Qijianglong, which is described as a genus. The first specimens were discovered in the 1990s, though the genus was only classified just this year. This is understandable, as it takes quite a long time for fossils to be identified reliably enough for taxonomists to be willing to identify them down to the genus level, which is a pretty specific taxa, comparatively speaking. --Jayron32 13:11, 10 March 2015 (UTC)

You might find more recent ones among the living dinosaurs. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 14:20, 10 March 2015 (UTC)

Systematics of birds is indeed an active area of research, but usually the debates/advances come through changing of higher order clades, not shuffling genera. See e.g. Bird#Classification_of_modern_bird_orders. It's very rare to discover a "new" genus of birds, and it is also pretty rare for bird generas to be changed/reorganized. All the recent action seems to be in ascertaining the relationships among the *formes orders. SemanticMantis (talk) 20:37, 10 March 2015 (UTC)

pH balanced soap and skin health

Some soaps manufacturers claim to produce soaps with pH of 5.5, and to be healthier than other soaps, with higher pHs. Is there any scientific base to this, or, is it just marketing gimmick? Would a pH 5.5 soap on a pH 5.5 skin have any effect? Isn't it the idea, to have a different pH?--Llaanngg (talk) 15:50, 10 March 2015 (UTC)

You can read a scientific study on this exact topic here. --Jayron32 15:58, 10 March 2015 (UTC)

There's a dead layer of skin on the outside of the epidermis, and a chemical peel is sometimes used to burn through it and remove some of it, giving the skin a more pink (for a Caucasian) appearance. Of course, it takes a seriously imbalanced pH to do that. With a moderate imbalance the effect would be minimal. However, if while washing your face you get some in your eyes, they are considerably more sensitive, so an argument could be made to use a balanced pH for that case. StuRat (talk) 15:59, 10 March 2015 (UTC)

So when the authors of the article linked above say "Each cleansing agent, even normal tap water, influences the skin surface. The increase of the skin pH irritates the physiological protective 'acid mantle', changes the composition of the cutaneous bacterial flora and the activity of enzymes in the upper epidermis, which have an acid pH optimum. The dissolution of fat from the skin surface may influence the hydration status leading to a dry and squamous skin" they're just talking nonsense are they? Richerman (talk) 16:58, 10 March 2015 (UTC)

Soap can definitely have a drying effect on the skin, by removing the normal oils. The solution is simple, though, just use some moisturizer to replace the oils. StuRat (talk) 22:44, 10 March 2015 (UTC)

Does a sports scientist or someone with a BSAT have to take the Hippocratic Oath?

Also, if someone (who isn't a nurse) isn't allowed to dispense medicine or be called a "Doctor" but still treats patients for health issues, does that person have to take the Hippocratic Oath?

175.156.96.153 (talk) 18:39, 10 March 2015 (UTC)

Nobody has to take the hippocratic oath. Not physicians, not surgeons, not internists, etc. And even if they do take the oath, breaking it (in and of itself) carries no penalty in any legal jurisdiction (though of course medical malpractice carries legal penalties in many places, and many times an incidence of malpractice may also constitute a breaking of the oath). See this NYT piece [1], or perhaps this bit from NOVA [2] for further info.

So the answer to all of your questions is a simple "no" - but of course many physicians do take the oath, and perhaps even some nurses, etc. Actually, you or I could take the oath right now, nobody is stopping us ;) SemanticMantis (talk) 19:28, 10 March 2015 (UTC)

It definitely inspires consumer confidence, in any service industry. If there are two decent restaurants on a block, similarly priced, and one advertises a promise to not harm you, it's safe to bet the competition will follow suit, rather than risk the implication. Of course, there are exceptions, but people tend to take their health more seriously after they're ill. So a Hippocratic Oath means more than a five star safety rating, even if it's less formal.

If a restaurant advertised a promise not to harm me, I'd be wondering why they thought it was necessary to do so.Iapetus (talk) 16:11, 11 March 2015 (UTC)

Unless the oathtaker is a liar, of course. InedibleHulk (talk) 22:56, 10 March 2015 (UTC)

Is there a single entity agreed upon as a universal "Hippocratic Oath"? I mean, the original involves swearing not to do kidney stone surgery or abortions, and I get the feeling it's been reworked considerably. But if it's not a single entity, then what it means to say someone took it or didn't becomes more nuanced. Wnt (talk) 01:06, 11 March 2015 (UTC)

See Hippocratic Oath#Modern use and relevance. As SemanticMantis has mentioned, there's no single form of the oath although some are more popular (such as the Declaration of Geneva) than others, and not everyone even takes any form, depending on university, country and other factors (including what you count as a form of the oath). Some universities give students the option of what oath they want to take, others let them right their own, so even within a certain year of university there's no guarantee it will be the same. And even if there is a single form normally taken, I'm guessing many would allow someone to take an alternative form if they can give reasons they are uncomfortable with the prescribed form. Nil Einne (talk) 01:33, 11 March 2015 (UTC)

Is there a state in the body that for one is health and for the other is pathological?

149.78.30.191 (talk) 20:38, 10 March 2015 (UTC)

Growing a beard on a woman or baldness for a lady could be counted pathological. Hair changing to blond for a dark haired person would be pathological, but the normal state for others. Graeme Bartlett (talk) 21:03, 10 March 2015 (UTC)

Men growing breasts (gynecomastia) — LongHairedFop (talk) 21:10, 10 March 2015 (UTC)

A good and extreme example is Sickle-Cell disease:[3]. There is no such thing as bad genes in the right ecosystem. --Aspro (talk) 21:28, 10 March 2015 (UTC)

I thought he meant something like California. μηδείς (talk) 21:42, 10 March 2015 (UTC)

Yep. Supposes one could say that Californians are in a right State. Especially if there're committing "Californication". No effective medication for that malady other than frequent doses of Red Hot Chili Peppers (ter die sumendum) per orem et auribus (forgive the grammar, as its all greek to me).--Aspro (talk) 22:03, 10 March 2015 (UTC)

My Dad had blocked arteries and claimed that he needed to have what for others was high blood pressure, just to get the blood to move properly. Of course, I wouldn't exactly call that "healthy", but it was healthier for him than if he had a typical "normal" blood pressure. StuRat (talk) 22:40, 10 March 2015 (UTC)

Large Hadron Collider upgrade

IIRC, before the Large Hadron Collider opened the first time, they were already saying that they were going to upgrade it. So they opened it, ran it for a year or so and then shut it down for two years for the upgrade (if I estimate the times about right). Wouldn't it have been better to just proceed with the upgraded version to begin with? Bubba73 ^{You talkin' to me?} 22:42, 10 March 2015 (UTC)

they knew it could be better and they needed baseline performance results. Classic process progression. Idea > creation > performance > feedback > areas of improvement > repeat. 66.87.83.115 (talk) 22:48, 10 March 2015 (UTC)

They knew it would be better - is it important to know how much better? It seems like the improved version would have gotten online and started producing results a lot sooner if they had done it directly. Bubba73 ^{You talkin' to me?} 22:57, 10 March 2015 (UTC)

Better in what sense? They already could do good science with the original layout. Also, the LHC is very much at the cutting edge of everything, so gaining experience with the less energetic version may well have helped to identify any snafus. The energy in the beam is quite significant - you don't want several TeV to go awry. Also see Perfect is the enemy of good. --Stephan Schulz (talk) 23:13, 10 March 2015 (UTC)

But then it was shut down for a long time for the upgrade. I think better in two senses (1) it must be less expensive to go directly to the upgraded version, and (2) we would be getting results from the upgraded version a lot sooner. Bubba73 ^{You talkin' to me?} 23:17, 10 March 2015 (UTC)

and those results could have been: we forgot to tighten the bolt that is allllllll the way inside there and now we have to take everything apart to get to it . Jus sayin66.87.83.115 (talk) 23:23, 10 March 2015 (UTC)

What they did, in my opinion, is kind of like: I need to put a new roof on my house, so I'm putting on one that will last 10 years, but before I do that, I'm already planning to take it off in 1 year and replace it with one that will last 20 years. Bubba73 ^{You talkin' to me?} 23:57, 10 March 2015 (UTC)

that assumes that you already know that a "roof" works correctly to block rain snow and elements.66.87.83.115 (talk) 00:07, 11 March 2015 (UTC)

To put it a different way, there's no guarantee it will be cheaper. If you're not sure how to do something, you could easily spend more because you make mistakes you wouldn't have otherwise if you had known before hand. In fact, for the same reason you can't even be sure you'll get results faster. Perhaps more importantly, even if you do get results faster, your results still may not have been as good as if you'd done a better job because you had all the information needed, including that you'd gain from the initial period. BTW, talking about "replace it" is also probably missing another point. I'm not sure how much of the upgrade is actually replacing anything, as opposed to adding new stuff. To use the IPs modification of your example, if you lack sufficient information on how to build your roof, building one with the plan to make modifications after you've learned what you need to know is not a bad bet. And the data already collected isn't useless, I don't know how it plays out in percentage terms but while some of the scientist involved in CERN may be partly helping with the upgrades, and some may be doing other stuff, others are surely working on all the data already collected. BTW, one year seems inaccurate. According to [4], or if you calculate from the figures in our Large Hadron Collider it was 3 years. I know there were some delays due to the quench incident (although actually I think if you include the time before it's been for longer than 3 years). And of course it likely depended on how quickly they learnt what they need to know, the quicker they could have upgrade. But I have doubts it was ever planned to run for only a year. Nil Einne (talk) 01:10, 11 March 2015 (UTC)

Apologies for any confusion caused by the above post. I should have just waited for others who knew more about this to respond. It does seem the gist of it is largely correct, except for the bit about the replacing vs upgrades (I was somewhat confused by the ref I provided), and also I was unclear on the timeline (the upgrades/replacement only coming after and mostly the result if the quench incident.) Nil Einne (talk) 00:39, 12 March 2015 (UTC)

The original design target was 7 TeV for each beam. However, it was found that not all the superconducting interconnects for the magnets were capable of carrying enough current to run at such a high energy; when one of them failed in 2008, it was a pretty catastrophic event, with large numbers of magnets quenching, loss of vacuum, and six tons of liquid helium boiled off in a flash [5]. The LHC leadership could have gone back to square 1 at this point and replaced everything. Instead, they made a strategic decision to perform an initial run at lower energy, which would be unlikely to trigger a similar failure, and hopefully discover the Higgs boson. As it turned out, this was a well placed wager. The upgrade largely involved replacing and testing interconnects to ensure they would be able to handle the full current needed to achieve the initial design energy. When you say "before the LHC opened the first time," I think you're actually referring to the period of time before the first successful run, but already after the 2008 quench incident. So this was already a fallback plan [6]. That kind of setback is not unusual for such a huge undertaking, with many individual components that have never been attempted before. --Amble (talk) 01:31, 11 March 2015 (UTC)

Politics often trumps science. As it happened, the lower energy runs produced results - hooray! everyone is a hero - and when they ask for more money, it becomes available because they've proven that they know their stuff and can produce big headline news. If they'd shut down until the upgrade was done, it would have been "This LHC is a money pit - we keep throwing more cash at it, and they never produce any results". This was the right way to do it...but that had little to do with science or logic. SteveBaker (talk) 04:20, 11 March 2015 (UTC)

Steve, please stick to topics you know something about. The LHC was already years behind schedule when the disaster hit. High-energy physicists were desperate for data. There were PhD students who needed LHC data for their theses. The LHC's lower-energy runs produced more raw data than the Tevatron did over its entire lifetime, and at a higher energy. It was a huge step forward. Analyzing the data takes years; without the lower-energy runs the experimentalists would have had nothing to do while the LHC was repaired. -- BenRG (talk) 06:36, 11 March 2015 (UTC)

Eh? What I said is in agreement with what you just said...they needed to pause the upgrades of the machine to produce some results to avoid criticism of being years behind schedule. SteveBaker (talk) 14:50, 11 March 2015 (UTC)

You appeared to claim the decision to go ahead at the lower energy levels was little to do with logic or science. BenRG appears to be suggesting it was actually the logical decision and good for science because it still produced a whole lot of data that people are looking at right now (or have already looked at). And in some cases the lack of such data would likely have negatively affected careers not because of criticism of their involvement edit: in the long delayed LHC (realisticly it's hard to blame PhD students for lengthy delays), but because they lacked data they'd been expecting. And so proceeding with the full upgrades/fixes early ony rather than running for those 3 years at lower energy levels was actually the poorer idea from a scientific standpoint, regardless of any possible cost savings, or producing higher energy level results sooner. Or to put it a different way, they primarily didn't pause the upgrades to avoid criticism, the paused because it was the far better choice for science and other reasons (such as being more sure the upgrades were sufficient). The fact that they may have reduced criticism was just an added bonus. Nil Einne (talk) 00:35, 12 March 2015 (UTC)

User:BenRG's answer is the correct one, but it brings up a question in my mind: is a lower-power run a control experiment for a higher-power run? In other words, if I think I found a 0.6-zilliEv particle in the results from a 1-zilliEv accelerator, do I have to run it just as long at half a zilliEv or less in order to show I don't get those results from the lower energy runs? Wnt (talk) 00:42, 12 March 2015 (UTC)

Here's an article from physics.org (a publication of the Institute of Physics): What does the 5 sigma mean? It provides an overview of the way that particle physics experiments validate statistical significance, and it is written at a technical level suitable for the enthusiast up to the intermediate-to-advanced physics student (and beyond). Nimur (talk) 01:01, 12 March 2015 (UTC)

Well, that talks about what five sigma is; I'm just wondering if lower-energy experiments are needed so that they know how many photons, etc. to expect by chance in the first place. Wnt (talk) 13:45, 12 March 2015 (UTC)

I don't think we can answer that in the general case: each specific type of predicted behavior needs its own unique null hypothesis. The process of peer review exists to ensure that experts check the validity of the hypothesis, in addition to verifying details of the statistics and the arithmetic.

Here's a better way to construct your mental picture of the situation. Few reputable physics presenters will publish a result that says something to the effect of "a new particle exists." Rather, that is the domain of the popular press. An actual paper published in Physics Review Letters will take a form more like: Evidence for the spin-0 nature of the Higgs boson using ATLAS data or Study of the Mass and Spin-Parity of the Higgs Boson Candidate via Its Decays to Z Boson Pairs. So, a very specific piece of observational data is studied, and its presence or absence can be checked against an easily-constructed null hypothesis that is appropriate to that exact data point. This may require different settings for the lab equipment, or perhaps not.

My goal here is not to couch an answer in a lot of technobabble; but it's to demonstrate that the hypotheses being tested are actually very specific, even if the popular press reduces the entire experiment to "run at high energy, see new particle." Nimur (talk) 14:11, 12 March 2015 (UTC)