Wikipedia:Reference desk/Archives/Science/2014 April 12

= April 12 =

Please identify yellow flowering plant
Can anyone identify this beautiful yellow-blossomed flowering plant? Thanks. μηδείς (talk) 01:23, 12 April 2014 (UTC)
 * Hard to tell. Could be an Alstroemeria (Peruvian Lily) or a Daylily or a True Lily.  -- Jayron  32  02:19, 12 April 2014 (UTC)
 * The image is way too fuzzy for me to have any hope, but the leaves look more dicot-ish than monocot-ish. Looie496 (talk) 02:34, 12 April 2014 (UTC)


 * Yes, it really does look like a lily, but the flowers remind me of Jimsonweed, the leaves do look dicotish (you can see they don't have parallel veins in the original), and I am fairly sure it is a member of Solanales, if not Solanaceae, and perhaps a Cestrum, whose leaves and size are similar. Not this seems to be one inflorescence from one shoot.  The screenshot is from 30:09 of episode 2 season 1 of Boston Legal.  The plant looks like a spike cut from a much larger bush. μηδείς (talk) 02:45, 12 April 2014 (UTC)


 * I left a note on the talk page of, I seem to have some recollection that he might know something about flowers. -- Jayron  32  02:59, 12 April 2014 (UTC)
 * It sure looks like some type of lily to me, but my wife who knows more than me says that the photo is not clear enough to narrow it down beyond that. Very similar flowers are growing by my front door right now, planted over ten years ago by the home builder. A slight correction, : You are right that I love flowers and post at least one of my flower photos on Facebook every day, along with its location, as I travel around Northern California on business and pleasure. This is my way of letting my friends know where I travel, and sharing a bit of beauty. But I am not an expert and usually rely on my Facebook friends for help identifying species. Thanks for remembering my interest in flowers, though.  Cullen 328  Let's discuss it  03:11, 12 April 2014 (UTC)


 * It's definitely not a lily. Lilies develop from a banana-shaped bud that splits along three axes, with the entire bud forming one flower, without green sepals.  These plants look similar, but the flower is conical, and the base, composed of sepals, remains green, while the flower grows beyond them.  The flower is much more like that of Jimson Weed, but yellow. μηδείς (talk) 22:03, 12 April 2014 (UTC)


 * It looks like an Orienpet hybrid lily, similar to this one but more yellow: http://www.thelilygarden.com/pages_lilies/orienpet_3.html --TammyMoet (talk) 08:37, 13 April 2014 (UTC) Could also be a Lilium hansonii but the flowers aren't open yet so I can't be definite. There's a photo on garden-photos-com.photoshelter.com but it's copyright so I can't link here. --TammyMoet (talk) 08:41, 13 April 2014 (UTC)


 * There's nothing wrong, User:TammyMoet, with linking to copyrighted work as long as it's the author himself who's publishing it. There's also the excuse of fair use for academic commentary, which this is. μηδείς (talk) 00:42, 14 April 2014 (UTC)
 * Oh well here goes. The habit (one stem with flowers on branches at intervals along it) is about right but the flowers point downwards instead of upwards. --TammyMoet (talk) 12:37, 14 April 2014 (UTC)

Is it true that some Prebiotic fibers could actually make us fatter?
I've heard that some particular types of Prebiotic fibers (whether they'll be Soluble, Insoluble but Fermentable, or Resistant starch), could actually give us the opposite effect and make us fatter, because unlike most of the Prebiotic fibers that supposedly make our Probiotic gut flora differentiate and (basically that's it), these particular aforementioned one's could also resemble the extra effect of breaking into notable amounts of available energy\handable sugars, in the gut, that will then enter the bloodstream directly.

What are the particular types of such "human-fattening prebiotic fibers", if any of them are actually known to Science except from general theoretical thought...? Much thanks!!! — Preceding unsigned comment added by 109.67.164.204 (talk) 08:55, 12 April 2014 (UTC)


 * See Dietary fiber. According to http://www.menshealth.com/mhlists/facts_about_nutritional_fiber/printer.php:


 * "Fiber is essentially composed of a bundle of sugar molecules. These molecules are held together by chemical bonds that your body has trouble breaking. In fact, your small intestine—can't break down soluble or insoluble fiber; both types just go right through you. That's why some experts say fiber doesn't provide any calories. However, this claim isn't entirely accurate. In your large intestine, soluble fiber's molecules are converted to short-chain fatty acids, which do provide a few calories. A gram of regular carbohydrates has about 4 calories, as does a gram of soluble fiber, according to the FDA. (Insoluble fiber has essentially zero calories.)"


 * "Fiber's few calories are more than offset by its weight-control benefits. The conclusion of a review published in the journal Nutrition is clear: People who add fiber to their diets lose more weight than those who don't. Fiber requires extra chewing and slows the absorption of nutrients in your gut, so your body is tricked into thinking you've eaten enough, says review author Joanne Slavin, Ph.D., R.D. And some fibers may also stimulate CCK, an appetite-suppressing hormone in the gut."


 * So note that the benefits of soluble dietary fiber, such as slowing the absorption of sugars and thus preventing blood sugar spikes followed by insulin spikes and sugar crashes, outweigh the negatives. StuRat (talk) 12:41, 12 April 2014 (UTC)


 * I'm intrigued by the OP's words "could actually give us the opposite effect". Opposite effect to what? HiLo48 (talk) 12:50, 12 April 2014 (UTC)


 * It is a bit tricky to figure out what they meant, but I took them to mean that fiber is normally good for weight loss because it fills you up and contains no digestible calories. Here the "opposite effect" would be if it causes weight gain because it does contain digestible calories. StuRat (talk) 12:57, 12 April 2014 (UTC)


 * You're right, that's exactly what I meant... 109.67.164.204 (talk) 15:17, 12 April 2014 (UTC)

Using aggregated data for statistics
If you want to do medical research, one way is to ask for instance GPs to sent all their medical records. This method has obviously huge implications regarding privacy. Even if data like Social Security numbers and names are omitted, sometimes it's not too hard to find out which record is about which patient. Another problem is that the GP doesn't have a guarantee about what the research is used for and by whom.

I'm wondering if it's possible that every GP collects his data (about, say, 2500 patients) and turns it into a file that contains facts like "5% of patients aged 10-15 have diabetes, of which 3% need insulin", etc. So part of aggregating the data takes place at the computer of the GP, and (more) anonymous results are sent to the research institute. Of course, if the practice has only a few people suffering from a particular disease, you might deduct some more information about them, but at least it's better than just sending separate records.

I was told that this method would make some research impossible, or at least very difficult. If the right set of questions can be asked and answered correctly by the system of the GP (like "of all patients using medication A, older then B, how many are also prescribed medication C"), is it true that for some research you actually do need the individual records? Joepnl (talk) 11:16, 12 April 2014 (UTC)


 * I don't see that approach working. For example, the portion of patients who "need insulin" will vary by doctor, as some may rely more on other methods to control diabetes. StuRat (talk) 12:26, 12 April 2014 (UTC)


 * The article Medical ethics notes the value placed on the patient-physician privilege. This is upheld because patients might withold sensitive information if unsure whether telling it can have consequences beyond their medical treatment, but it is not an absolute privilege because various laws require physicians to report STD's, gunshot wounds, child abusers and vehicle drivers impaired e.g. by epilepsy. Medical research involving both medical ethics and Research ethics raises questions like the OP's question. Shall results of Human subject research be published for study even if their collection was abusive and unethical (the WW II examples are well known)? Is research without knowing consent of the subjects justifiable? (Ethical questions are raised over Stanley Milgram's 1961 experiment of misleading subjects into applying an increasing scale of shocks to people ostensibly to "improve" them, yet today Wikipedia administrators believe themselves empowered to apply electronic blocks on an identical increasing scale that ends in indefinite dehumanisation of participants.) The problem with the OP's proposed procedure is that a General practitioner is already hard pressed by lack of resources and pharmaceutical company salespeople and has a skill set focussed on giving care to individual patients that is different from being an objective data-collection functionary. The GP might argue in modern terms to have "sworn by Apollo" never to "cut for stone" (take on the role of a surgeon/researcher ?) and "keep secret" (the patient's identity). These considerations detract from the end-to-end transparency, verifiability and accountability that medical research demands. (Readers may be interested to see how voluntary reports on side effects of medicines are collected in Norway, a country with well developed Publicly funded health care. On this site in Norwegian anyone living in the country is invited to report side effects they or others experience from medications. The pink button links to the reporting form; this appears however only for residents.) 84.209.89.214 (talk) 13:12, 12 April 2014 (UTC)


 * Well, actually the problem is that many GPs in The Netherlands don't seem to realize what kind of data they're sending out for research (or many other purposes). As a tech person, who does know the kind and volume of data leaving the practice without the doctor or patient knowing exactly what's happening, that bothers me. A lot of really important research can't be done without data from their practices, however. So I'm looking for a way that would be good enough for the researchers and at the same time doesn't imply that the most intimate things people share with their doctors can't be traced back to a single patient by them. Joepnl (talk) 13:32, 12 April 2014 (UTC)


 * Yes, some research couldn't be done this way. You would have trouble doing a longitudinal study for example. Furthermore, if you need to know information like diet, which GPs don't routinely collect, you would not be able to do the research. But the important thing is that this approach would open up a new avenue for research. It would be difficult to get it through ethics committees, so it might have to be handled through private institutions, which are often subject to different ethical processes. IBE (talk) 13:29, 12 April 2014 (UTC)


 * If you're not already aware of it, you might want to read around the subject of NHS Connecting for Health and the resistance to making this data available to researchers, e.g. the big opt-out. 86.146.28.229 (talk) 14:23, 12 April 2014 (UTC)


 * At the level of technical statistics, the problem you face when dealing with aggregated data is heteroscedasticity, also known as inhomogeneous variance. In spite of the tongue-twisting term, that article might be helpful to you. Looie496 (talk) 14:21, 12 April 2014 (UTC)
 * That's the beginning of the problem. I think whenever you snarf up a bunch of data without


 * Yes, that's the shot, make it easy on everyone by using some slang only you know the meaning of. Does "snarf" mean fuck up, get rid of, collect, tabulate, or stick up one's bottom? Myles325a (talk) 04:09, 15 April 2014 (UTC)

looking at it, you're really taking a huge risk of being completely clueless about what it means. For example, suppose you take data from 50 doctors about whether high blood pressure brings a higher risk of diabetes. You might ask some, even most of them whether they test patients for diabetes because they have high blood pressure and they say no, but then somewhere in the pack there are doctors, or doctors who inherited patients from other doctors, who did test their patients specifically because they had high blood pressure, or the patients were otherwise encouraged to get testing, and so of course more diabetics are reported from that group. Actually, I wouldn't trust even one set of researchers writing about data they haven't actually looked at, because it's prone to chicanery. For example, I remember that during a crucial moment in the run-up to the Communications Decency Act a team from Carnegie Mellon tossed out a study claiming that huge amounts of child porn were posted to Usenet. Of course, they couldn't look at the data - that would be illegal - so they used keywords, and counted anything that said "no pubic hair". Problem is, "no pubic hair" was a way of saying "legal in Japan", a country with a grudge against lovely carpets. Several other such howlers were noted by subsequent papers after the bill had been passed (and thank God, struck down by the courts) So there are a lot of reasons why I'm not going to trust a study where the collaborators don't have a way of really drilling down to the original data set. Wnt (talk) 15:26, 12 April 2014 (UTC)


 * I don't see much problems here if you analyze the data using Bayesian analysis that includes a detailed model of how doctor-patient relations work in practice. By doing the analysis from first principles without making any assumptions, you can get useful information from the raw data. Basically, if you can calculate the raw data corresponding to any given hypothetical real world situation then given the raw data, computing the most likely real world situation is a so-called Inverse problem. Count Iblis (talk) 17:23, 12 April 2014 (UTC)
 * Unfortunately, an Inverse problem approach to medical research may serve to perpetuate reliance on a bad causation model. For example, in Medieval medicine of Western Europe physicians drew on the Doctrine of signatures superstition which stated that God had provided some form of alleviation for every ill, and that these things, be they animal, vegetable or mineral, carried a signature mark indicating their usefulness. Ideas about the origin and cure of disease based on a world view dominated by factors such as destiny, sin, and astral influences would eventually be superceded by scientific breakthroughs such as vaccines, antibiotics and Germ theory of disease. Enjoy reading Homeopathy and Its Kindred Delusionsa (free on Wikisource) to see that there is still work to do. 84.209.89.214 (talk) 20:30, 12 April 2014 (UTC)


 * The article differential privacy and its references might have some info you can use. 70.36.142.114 (talk) 23:13, 12 April 2014 (UTC)


 * I don't know about OS, but here in Oz, doctors are kinda overworked, and most still depend on paper records. If one were to approach a doctor with, say, 2000 patients on his or her books, and ask him or her to tabulate all the data within and reduce it to a couple of pars and send it over asap for your research, a task which would prob take him or her a couple of weeks full time, he or she might ask you to come over and do it yourself, except of course it would breach privacy concerns. Myles325a (talk) 04:09, 15 April 2014 (UTC)

Dynamic load.
How do you find the maximum load, as well as max moment and stress on a cantilever beam if you have the dynamic load factor? I calculated the DLF using FL^3/3EI but I'm lost on where to go from here. — Preceding unsigned comment added by 82.132.236.40 (talk) 12:37, 12 April 2014 (UTC)


 * If you only have one dynamic load on the beam, it seems to me that the max moment and stress would both occur when that dynamic load is at the maximum. With multiple dynamic loads, the situation is more complex.  There the max moment and stress could occur when one of the dynamic loads is at it's max, but this isn't always true, and even if it is, it isn't necessarily the largest dynamic load that's at max at that time.


 * A computer simulation may be in order in such cases. If the dynamic loads vary independently of each other, you might vary each independently in the simulation and calculate the moment and stress at each time to determine the max for each (again, the maxes may occur at different times). StuRat (talk) 12:50, 12 April 2014 (UTC)


 * Thank you for your answer but I don't quite understand what you mean. The dynamic load factor is a ratio of the deflection as a result of the dynamic load to the equivalent static load deflection. So from this point, I would probably need to do some sort of energy analysis to find the maximum force but I'm not sure what the correct equation is. — Preceding unsigned comment added by 2.218.65.60 (talk) 14:15, 12 April 2014 (UTC)


 * There are software packages that are used to calculate the size of beams required for construction projects, such as this one that may be of use. Richerman    (talk) 20:27, 12 April 2014 (UTC)

FL^3/3EI is a deflection not a factor. So your question doesn't make much sense. What i'd expect is a DLF of say 3 times the static load. In the case of simple systems people often assume a DLF of 2, as that is the maximum force a suddenly applied load will give, in certain situations. So if you were to suddenly apply a 10 kgf force, the stresses and deflection in the beam would be the same as a 20kgf static load. as a dynamics guy the unstated assumptions in that approximation makes me shudder, but it is common one in textbooks. Greglocock (talk) 23:15, 16 April 2014 (UTC)

Viagra vs cialis vs levitra
What ones make you last the longest in bed--&#91;&#91;User:A915&#124;A915&#93;&#93; a (talk) 18:26, 12 April 2014 (UTC)
 * I'm afraid that Wikipedia editors are not allowed to give medical opinions. You'd need to have this discussion with your physician.  -- Jayron  32  18:28, 12 April 2014 (UTC)


 * If Wikipedia can't help, I might be able to by sending the contents of my Spam box to OP. I subscribed to a few of the "enlarge your organ" offers, and as a result, I now have a donger that's 10 metres long. (And you should see it when I get excited...) Myles325a (talk) 04:13, 15 April 2014 (UTC)

The information can be had by comparing what's in the articles. μηδείς (talk) 21:52, 12 April 2014 (UTC)


 * I would think not taking such a drug will make a person last longest in bed, if erectile dysfunction prevents him from finishing. Wnt (talk) 04:41, 14 April 2014 (UTC)

Cleaning electroporation cuvettes which use conductive polymers
I have some electroporation cuvettes for the purpose of transfecting mRNA/DNA into eukaryotic cells. Reuse is forbidden by the manufacturer but I wondered how an unscrupulous person might be able to clean and reuse it anyway. The electrodes are conductive polymers (they produce fewer toxic ions during the electrolysis which I suppose is inevitable during an electroporation). They would need to be cleaned without trace of anything that went into them. --129.215.47.59 (talk) 13:24, 2 April 2014 (UTC)
 * Simply rinse them in 70% ethanol a few times, followed by a good soak. Could even store them in the 70%. Before use, rinse in dH2O thoroughly to remove any ethanol traces. Works fine. And most certainly not unscrupulous, just sensible. If I followed manufacturers instructions on everything I use in the lab, I'd be spending three times as much on consumables as I do! Fgf10 (talk) 19:01, 2 April 2014 (UTC)
 * Thanks. I appreciate the advice. 78.148.110.69 (talk) 12:00, 5 April 2014 (UTC)


 * Thanks but I'm not sure that rinsing with ethanol would remove all traces of DNA. 129.215.47.59 (talk) 18:30, 12 April 2014 (UTC)


 * Definitely not. 70% ethanol is what you use to wash salt out of a DNA pellet after centrifugation.  Of course, if you're transfecting _the same_ DNA each time that may not be much of a problem.  Oh, and check a search engine for stuff like  -- but for more precise (and recent) results specify your manufacturer name. Wnt (talk) 21:23, 12 April 2014 (UTC)

Do pet shop animals have worms or parasites
Do animals purchased from a pet shop such as petco or petsmart such as rats and mice have worms or parasites or anything else that is transmittable to humans. What is the likelihood of them having it and how easy is it to transfer to humans. --Tarhound21 (talk) 18:41, 12 April 2014 (UTC)
 * If you want to know what the policies of these companies are with regards to the treatment of animals they sell before they sell them, the best thing to do is to contact them directly. You are highly unlikely to run into anyone on this particular webpage who works for either company.  Here is how to contact PetSmart and here is how to contact PetCo.  -- Jayron  32  18:56, 12 April 2014 (UTC)
 * If you want to know more about zoonoses you can contract from rodents see Zoonoses of House Pets Other Than Dogs, Cats and Birds. Infections from pet rodents are rare but not unknown - allergic reactions are much more likely. Richerman    (talk) 19:34, 12 April 2014 (UTC)


 * If you're actually going to buy such animals and are concerned, get a consultation with a local vet, and they will gladly prescribe an prophylactic anti-parasitic. In general, pet shop rodents come from lab stock and are intentionally kept disease free by isolation.  But there's no guarantee those sexy feral mice aren't seducing the lab ladies, and leaving contaminated droppings.  Ask the owner of the pet store where his stock comes from.  Also, avoid eating their droppings yourself. μηδείς (talk) 21:58, 12 April 2014 (UTC)
 * For an immaculate well-bred Mus musculus with good references, choose a Laboratory mouse supplier. 84.209.89.214 (talk) 23:47, 12 April 2014 (UTC)
 * Really? In the UK no animal laboratory would supply animals to a pet shop and laboratory animal suppliers wouldn't sell their stock to the general public. Richerman    (talk) 00:19, 13 April 2014 (UTC)
 * Yeah, you got us. The pet stores actually bred an entirely new race of ersatz white mice and rats to look like lab animals to fool the public.  This guy explains the scam. μηδείς (talk) 01:43, 13 April 2014 (UTC)
 * Well really it was somewhat the other way round. Actually, I'm surprised that "the mouse woman of Granby" Abbie E.C. Lathrop is still a red link. She really was a pioneer and an unsung American heroine see:. If no-one gets round to it soon (shame on you American women of science!) I may have to write one myself :).  Richerman    (talk) 09:02, 13 April 2014 (UTC)
 * See also fancy mice (the sort sold in pet shops) versus laboratory mice. Lathrol started supplying fancy mouse breeders, before supplying laboratories. 86.146.28.229 (talk) 15:56, 13 April 2014 (UTC)
 * I guess you both probably know but for the benefit of other participants like the OP, the wider point which μηδείς may have missed or just intentionally ignored in their later comment, if it's true (and I think there are reasons to think it is), laboratory mice are often different lines from different suppliers nowadays and likely for a long time, this mostly negates the point μηδείς seemed to be making in their first comment.
 * Because even if it were true pet shop mice came from laboratory mice strains 10, 20, 100 or whatever years ago (instead of vice versa), it change the fact that this was a long time ago. This is enough for even a significant difference in genetics although that doesn't seem relevant since we were not talking about that.
 * What we were talking about, and what the years and many generations is definitely enough for, is for parasites/transmittable diseases to have arisen in the population which may not be common in laboratory mice. Or for parasites/transmittable diseases to often occur even coming from a variety of sources even if not endemic. And it is resonable to expect that considering the customer requirements and expectations and money involved, laboratory mice are far more likely to be disease free than pet shop mice.
 * While there may be "no guarantee those sexy feral mice aren't seducing the lab ladies, and leaving contaminated droppings", it's resonable to expect there's even less guarantee in your typical pet breeding outlet. In fairness μηδείς did say to check with the pet shop but I'm guessing in some cases the "isolation" could easily be; 'my cat knows it's not allowed to catch the white mice, but other mice are fair game, and oh did I mention like many cats, it is a literal game which often happens inside my house?'
 * In other words, saying they 'come from lab stock' doesn't really mean much when that stock may have been many many years ago. (Of course Richerman's reply was to the IP anyway and directly negated what the IP said yet didn't really directly address anything μηδείς said, so there's even less reason for μηδείς's unhelpful sarcasm.)
 * Nil Einne (talk) 16:22, 13 April 2014 (UTC)
 * We did a yearlong class project in seventh grade that involved raising mice (we bred them to see if we could discern any mendelian patterns in coat color). I came across many sources that said white mice kept as pets and lab mice had the same origin. I don't remember what those sources were. Of course now the pet trade has bred all sorts of fancy mice, and labs have moved on to highly specialized strains for certain sorts of research.  But domesticated and lab mice and rats had the same origins according to many sources. μηδείς (talk) 17:25, 13 April 2014 (UTC)
 * Lab mice were originally derived from fancy mice see: but as Nil Einne says, whatever happened at the beginning of the 20th century has no bearing on the health status of any mice you could obtain today. Because of that I presumed you meant that US pet stores obtained their stocks from animal labs and, having bred rats and mice (as well as other species) in UK research laboratories for nearly 40 years, I was surprised by both that reply and the following one and was asking a genuine question. If it came across a condescending it wasn't meant to be - I'm just interested in how the regulations differ in different parts of the world. And, just in case anyone gets the wrong idea, my comment about "shame on the American women of science" was not meant to be taken seriously. Richerman    (talk) 17:58, 13 April 2014 (UTC)
 * Lol. μηδείς (talk) 20:21, 13 April 2014 (UTC)
 * It isn't really that unheard of for a lab to have excess mice to get rid of that end up going home with students rather than getting killed with CO2 (though it's a miniscule fraction of the overall number). Technically some of them might be GMOs but inbred lab strains are so poorly adapted for life outdoors I doubt anyone cares much.  After a generation (or less), I assume they are officially pet mice again.  It's also not unheard of to find that your conventionally housed lab mice are positively infested with pinworms.  Wnt (talk) 23:44, 13 April 2014 (UTC)