Wikipedia:Reference desk/Archives/Science/2015 January 21

= January 21 =

Is Harvard into a bogus product or is this solid science?
I am surprised that a Harvard study builds upon the concept of toxic light and even advertizes a yellow filter for protecting our eyes from visible blue light (through their company Reticare), which is supposed to be toxic. Although I'd call it right-away pseudo-science, a rip-off, or at least a useless product at best, I'd be interested at some reality check of my pre-conception. Could my smartphone + computer be damaging my eyes through too much blue light? If yes, what is the difference of a light coming from a screen from day-light (which is much stronger)?--Noopolo (talk) 14:43, 21 January 2015 (UTC)


 * Looks legit to me, but "toxic light" is an odd expression. The Wikipedia article is phototoxicity.--Shantavira|feed me 15:22, 21 January 2015 (UTC)


 * First, it's not really "Harvard" research, it was performed by Celia Sánchez-Ramos, who is a researcher at Complutense_University_of_Madrid. The latter is also a highly reputable and old university, but I just wanted to clear that up. It's on the rcc.harvard page because Harvard has some sort of partnership arrangement with CUofM. It's primarily a branding thing to associate the names so that they can share in eachother's prestige.
 * If you don't want to read the original research article, here is a poster that the team presented at some conference, and here  is some pop-sci press saying "That study found that LED radiation caused significant damage to human retinal pigment epithelial cells in vitro." - emphasis mine. While in vitro studies can be an important first step, we should be careful before jumping to conclusions about how these effects will play out in the human body. See also High-energy_visible_light (also known as simply blue when people aren't talking about health concerns), particularly references 2,3 which also discuss recent results on blue light and macular degeneration.
 * In short, this research is not totally crazy woo-woo pseudoscience. At the same time, there is not yet strong evidence and wide support support for the general claim that exposure to blue light from LED displays significantly damages human eye sight. (WP:SYNTH:) There does seem to be some scientific reasons that indicate caution in LED/blue light exposure. I believe that calling it "toxic light" is a bad move for a scientist to make, but again that's my opinion. Getting anything much more specific than that will require carefully reading many recent scientific articles, and perhaps reading even more background material to make sure you understand the papers. SemanticMantis (talk) 15:40, 21 January 2015 (UTC)


 * It looks like the argument is that macular degeneration is more common with increased sunlight exposure, and blue light might specifically be the frequency to blame. But "toxic light" is basically just blue light.  What I'm not ready to evaluate at the moment is how bright the retinal impact of blue light from a monitor is relative to natural sunlight, since the pupils are more constricted, and perhaps other adaptations at the cellular level are made.  Also, the natural lens will vary from in vitro, because, improbable as it seems, it turns out that the human lens actually has its own special sort of pigmentation, a yellow tint from a kynurenine derivative (thus chemically similar to pigment in a butterfly's wing).  This blocks mostly UV but also some blue light. Wnt (talk) 16:08, 21 January 2015 (UTC)


 * If it's an in-vitro study, then the filtering effects of the lens and vitreous humor will probably not have been accounted for. But there certainly can be issues with 'unnatural light' because all "real" light sources are a broad mix of frequencies and the eye controls the amount of light entering the eye using the iris based on some measurement of the light that's detected in the retina.  With the single-frequency light from lasers and LED's, it's hypothetically possible that you could find frequency distributions that the eye/brain would fail to recognize as a cause for shutting down the iris.   In that way, it would take much less energetic light to cause damage.  That said, I don't think TV/Laptop/Tablet/Phone screens are likely to be a huge issue because we generally display a wider range of frequencies (Red, green and blue).   But I could imagine that very bright single-frequency LED's could be pushing out what seems to be a safe amount of light (on the basis of the iris closing down tight to block most of it), yet somehow tricking the eye into not shutting down the iris.  That certainly happens with IR and UV light, which are dangerous in much lower intensities than visible light. SteveBaker (talk) 17:24, 21 January 2015 (UTC)


 * I think the OP was also concerned about the fact that the research was funded by Reticare, a company selling $30 screen protectors, claiming they "Reduces the risk of cell death of the retina by up to 89%." Mr.Z-man 17:07, 21 January 2015 (UTC)


 * Yeah...that's a very, very large red flag right there! 89% of almost-zero risk is still almost-zero risk, and I'm *deeply* suspicious of claims with such precise percentages (89%...not 90%) coupled to the phrase "up to" - meaning "anywhere between zero and".   The only bigger red flag is when they say "up to XXX or more!" meaning "anywhere from zero to infinity, we just don't want to say". SteveBaker (talk) 17:24, 21 January 2015 (UTC)
 * xkcd... always relevant. - ¡Ouch! (hurt me / more pain) 06:51, 26 January 2015 (UTC)


 * All I see is that they are hosting a copy of the pdf, which isn't that odd at all. In the 2013 article in Photochemistry_and_Photobiology (my second link), the acknowledgements say only "This work has been supported in part by Fundación Mapfre (Spain)" - according to the journal's policies (and I think all Wiley journals), funding sources should be listed in the acks. Now, her website  does show her apparently endorsing Reticare products (and others), or perhaps certifying that they do indeed block certain types of light (sorry, I don't read Spanish). She may even have been paid for some endorsements, or have licensed some of her patents to them, but that is not the same thing as funding research. Anyway, I see no reason to believe that Reticare funded the study linked by OP. Where do you see that the research was funded by Reticare? Seeing as she has started some sort of spin-off company, she will have been under intense scrutiny from her university regarding her potential conflicts of interest. SemanticMantis (talk) 17:56, 21 January 2015 (UTC)


 * It says right on the right side of, "Supported by Reticare." Mr.Z-man 18:09, 21 January 2015 (UTC)
 * Oops, I was so focused on checking her journal articles I didn't double check that link! Sorry about that, and thanks for the correction. Anyway, it's a little unclear what that statement means. My understanding is that if she received support and/or funding for the research leading to the publication of her 2013 paper on the topic, the authors would have had to declare it in the paper. I have not published in that Wiley journal but I have published in other Wiley journals, and there's a whole list of things you have to say about funding sources and identify even potential conflicts of interest. SemanticMantis (talk) 19:31, 21 January 2015 (UTC)


 * Checking the Spanish sites about this issue: the research was funded by the Complutense University of Madrid mainly, where Celia Sánchez-Ramos works. She then created the company Reticare, which started an intense marketing campaign to push the product, including the public Spanish TV, youtube and trade shows, in Spain and internationally. Reticare obviously endorses the work of its creator. And the Complutense doesn't seem to care or know about any problem with this product. Harvard is just being used as a sort of trampoline, so as to endorse the product for marketing purposes. I don't see any trace that researchers at Harvard worked or endorsed the product. I'd say it's a rip-off, but certainly Harvard is not behind it, maybe they are not even aware of what their partners are doing with its name. It looks like a giant rip-off though, comparable to water filter scams (that transform perfectly save tap water into perfectly save tap water).--87.222.211.207 (talk) 19:02, 21 January 2015 (UTC)


 * Looks to me like Harvard needs to seriously reconsider this partnership with a Spanish University with questionable ethical standards. StuRat (talk) 19:25, 21 January 2015 (UTC)
 * The fact that she started a company and affiliated with other companies based on her research does not, by itself, indicate any breach of ethics or questionable standards. This sort of thing is very common, and the professors involved usually receive extra scrutiny from journals, funding sources and review boards, not less. Also, rcc.harvard is clearly controlled by Harvard. The notion that this affiliation and research is something that slipped by Harvard's notice is frankly absurd. Honestly if I cared about such things I'd be tempted to remove a few of these baseless assertions about this scientist and her university due to WP:BLP violations. Neither you nor the IP have any sources, you're just making things up. If you want to claim ethical violations, you'll have to show some actual evidence. SemanticMantis (talk) 19:38, 21 January 2015 (UTC)
 * I agree that a creating your start up based on your research is an acceptable, or even desirable, process. However, there are more than red-flags about this product and thorough analysis about its "science" (in Spanish). The evidence to develop the product looks thin at best. Obviously, the article can be peer-reviewed and even right, but you can not draw the conclusion from it that there is some kind of toxic light that has to be avoided at all cost (or at a cost or €30, which is what these filters can cost). However, I still don't see any endorsement coming from the Harvard part. The affiliation did not obviously slip by Harvard's notice, but they won't also check any single detail of what people are doing there. The director (José Manuel Martínez Sierra) of the  RCC is clearly from the Complutense, and he doesn't have a background in science. So no wonder that you see such "science" there. --87.222.211.207 (talk) 20:01, 21 January 2015 (UTC)
 * Ok, I think we're in total agreement here. I was in no way defending the scientific support for any product. I only meant to say that the research papers appear to be real, peer-reviewed work, that have shown evidence of their claims. Some of these claims appear to be minor, and they key 2013 paper only looks at in vitro results, from which we can't easily generalize. I see no reason to question any of the ethics of the research methods or funding. I agree that it seems no Harvard scientist have endorsed the commercial products. I am also skeptical of the potential benefits of the advertised products, and I'll take your word for it if the business is playing fast and loose with the implications of the research. I suppose it is possible for a professor to behave ethically in their research but behave unethically in how they use that research to promote a product. As I understand it, the latter wouldn't be under the domain of standard university and funding-source ethics review panels, it would be more about the legality of making advertising claims. SemanticMantis (talk) 22:43, 21 January 2015 (UTC)


 * If it's a simple as blocking blue light, you could probably just turn the blue down on your monitor, no need to pay $30 for an absurdly overpriced device. And the fact that they don't mention this means they are more interested in getting your money than in protecting your eyes.  StuRat (talk) 18:01, 21 January 2015 (UTC)

The odd thing is that there is a lot of evidence that exposure to blue light in the evening alters your circadian rhythm and interferes with sleep patterns, which would be a good selling point for the filters anyway. Richerman   (talk) 19:51, 21 January 2015 (UTC)
 * Come on Richerman, the fear mongering (toxic light from your smartphone will let you blind), is much more powerful marketing than that, which could be dealt with turning the screen brightness down or reducing the use of your devices. --87.222.211.207 (talk) 20:13, 21 January 2015 (UTC)


 * Conceivably there is a difference between turning down the blue light from a monitor and using a special yellow filter. After all, an artificial "blue light" could extend all the way up into the UV, and clearly it would be healthier for the eyes to block all the UV than half of the total light.  That said, the obvious solution is for the manufacturer to have blue colors in an RGB monitor that look blue but contain as little higher-frequency light as possible, i.e. are sharp blue, and so long as that's what he does, the only other tip is not to have your monitor really really bright lest you be at somewhat elevated risk for macular degeneration someday. Wnt (talk) 20:40, 21 January 2015 (UTC)


 * Not to mention that sunlight impinging on a sheet of paper probably reflects a ton more blue light than a phone screen emits (that's why it's hard to read your phone screen when it's in full sunlight). The brightest screens we have these days emit about 300cd/m2, a sunlit surface receives about 60,000 cd/m2 and white paper is between 60 and 70% reflective.  So reading a book in sunlight will result in about 120 to 140 times more light than your cellphone screen...since sunlight covers more or less the entire spectrum - it's going to have vastly more blue light in it than your phone.


 * So shouldn't this brave researcher be out there making yellow-tinted book covers instead? (Well, no - because people would laugh at her and she wouldn't be able to sell them to the neo-luddites.)


 * The only way for this not to be the case would be if ones eyes were being damaged by a very narrow band of frequencies that just happens to include the specific frequency of a blue LED. This would be a most unfortunate, and incredible coincidence.  But, in that case, it's conceivable that the blue LED might put out more light in this special 'danger frequency' than you'd find in reflected sunlight or light from the (blue!) sky.


 * Clearly there hasn't been NEARLY enough research done on this (particularly not if they did these tests in vitro) to rush out and develop a product that'll fix it. So I'm certainly ready to call "bullshit" on the product - and the research is "highly preliminary", at best, at this point.   The financial link between the researcher and the product really doesn't make for a convincing study - and promoting this as "Harvard" research is just underhanded.  Until this has been reproduced in-vivo by multiple independent labs, I'd be highly skeptical.


 * SteveBaker (talk) 23:39, 21 January 2015 (UTC)

IUCN Red List Status Code "CD"
There are IUCN Red List Status Codes listing the degree of endangerment of cetaceans. There is one, "CD" that I'm not sure about. I can't tell if it should be "CR" for Critically Endangered or "DD" for Data Deficient. From what research I have done, I cannot find an explanation for the code "CD". Can you verify and give a definition or correct?

http://en.wikipedia.org/wiki/List_of_cetaceans

Thank you 71.68.111.76 (talk) 16:31, 21 January 2015 (UTC)


 * CD is erroneous and doesn't relate to anything. If you select each of the individual cetaceans which have that "CD" rating, they are either rated as "Data Deficient" or "Least Concern".  It would seem that the list needs to be updated.  The Rambling Man (talk) 16:40, 21 January 2015 (UTC)
 * Yep. For reference, here is the IUCN's document on categories and criteria, showing clearly no "CD" category. Any species with "CD" will have to be checked by hand. Anyone interested can check via species name directly at the redlist here . SemanticMantis (talk) 19:45, 21 January 2015 (UTC)
 * It's not erroneous. It is, however, outdated. It means it's a Conservation-dependent species. It's from the depreciated system of categorization in the IUCN Red List v2.3 (released in 1994). It's usually written as LR/cd since it's a subcategory of the Lower Risk category, along with LR/nt and LR/lc - Near Threatened and Least Concern. The latter two have been formalized as their own categories (NT and LC) in lists from 2001 onwards. LR/cd is no longer used, and is mostly subsumed into NT.-- O BSIDIAN  †  S OUL  07:46, 22 January 2015 (UTC)
 * Aha! I feel a bit silly for only checking the latest classification, thanks for the clarification. I still think our articles should be updated to the newer terminology and coding though. SemanticMantis (talk) 14:20, 22 January 2015 (UTC)
 * Definitely. I think the list was probably compiled from a single pre-2001 source rather than being compiled species by species, hence the incongruity when checked against the individual articles. You can actually confirm that the ones listed as CD in the Wikipedia article were once regarded as LR/cd. For example: the striped dolphin is listed as "CD". Its IUCN Red List 3.1 page classifies it as LC now, but includes the notes: "1996 – Lower Risk/conservation dependent (Baillie and Groombridge 1996); 1994 – Insufficiently Known (Groombridge 1994)" in the History section.-- O BSIDIAN  †  S OUL  14:44, 22 January 2015 (UTC)

Thank you so much for your responses! You guys are awesome!71.68.111.76 (talk) 02:20, 26 January 2015 (UTC)

Are trichophyton fungi a type of mold?
They are dermatophytes, but are they molds? The Transhumanist 19:48, 21 January 2015 (UTC)

What phylum do they belong to? The Transhumanist 20:25, 21 January 2015 (UTC)


 * Mold is a term that isn't monophyletic but refers to growth as hyphae. The Trichophyton article says they have hyphae.  This being semantics, I'm a little wary, but it seems like a QED to me.


 * The article also says "Division" Ascomycota. "Division" is a botany term for phylum; what seems jarring is to see it used in the context of fungi, since we think of them as an offshoot of the animals, but there's no accounting for tradition.  According to Phylum even the botanists have started to switch away from "division" now. Wnt (talk) 20:47, 21 January 2015 (UTC)
 * That's because the ICN covers "algae, fungi, and plants", in part for historical reasons . As I understand it, there was a recent (2012 and ongoing) dust-up between the mycologists and botanists about how to refine the naming conventions. I agree with your assessment that it's a mold by convention, but that term is a little silly. We don't call common button mushrooms molds, but of course they have plenty of hyphae too. It's safest for OP to say it's a fungus, or an Ascomycote if more specificity is needed.SemanticMantis (talk) 22:52, 21 January 2015 (UTC)


 * Not only are they all fungi, they're in the same taxonomical family, making them about as close terminologically as the Canidae which includes all the dogs, wolves, jackals and foxes. (Such comparisons at a distance are a bit subjective, but it gives you an idea of their closeness.


 * μηδείς (talk) 23:41, 21 January 2015 (UTC)


 * "Dermatophyte" is not a taxon. It has no rank, nor has any basis in phylogenetic relationships. It's simply a general term referring to a certain type of organisms that inhabit a certain environment, or look or behave in a certain way. In this case it's a medical categorization of fungi that infect the skin. Similar terms include epibiont, epiphyte, ectoparasite, plankton, anaerobe, nekton, etc., and yes mold.


 * If you are questioning the "-phyte" suffix, fungi are simply traditionally studied along with plants under botany. Since the traditional perception was that all non-motile and sessile organisms were "plants". This is why they are still somewhat treated similarly and are subject to ICN (rather than ICZN), as mentioned, despite evolving from very different "branches" altogether.


 * Phylogenetically, fungi are only distantly related to plants. True fungi are opisthokonts (and unikonts) and thus belong to the same branch as animals; while plants are archaeplastids (and bikonts), belonging to the same clade (though still separate branches) as dinoflagellates, ciliates, and foraminiferans (which were once considered "animals"). There are exceptions: water molds (oomycetes) are possibly under Hacrobia or the SAR supergroup (previously Chromalveolata), which is still within the Plants+HC+SAR megagroup; while slime molds (myxogastrids) are under Amoebozoa (again, a completely separate branch from both animals and plants).


 * As for the second question, all dermatophytes in that article are under the Phylum/Division Ascomycota (ascomycetes)-- O BSIDIAN  †  S OUL  08:30, 22 January 2015 (UTC)


 * LOL I didn't realize the question was simpler. Didn't read title, thus misread context. But yes. The only criteria for being called a mold is that their body form consists of multicellular "threads" (hyphae) rather than solitary cells (in which case they are known as yeasts). Trichophyton, like other dermatophytes only exhibit the hyphae form. -- O BSIDIAN  †  S OUL  09:00, 22 January 2015 (UTC)
 * No worries. I took the liberty of un-striking your response, I hope you don't mind. Sure, it's a little tangential, but it is still a very good summary of some of the background classification, and it has lots of good relevant links. So I think it deserves to be more easily read :) Also, the idea that we strive for monophyletic groupings and that polyphyletic or paraphyletic should be avoided can always bear to be repeated. SemanticMantis (talk) 14:18, 22 January 2015 (UTC)


 * Found relevant coverage on WP at Mold health issues. The Transhumanist 10:44, 25 January 2015 (UTC)