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CharonY

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Everything posted by CharonY

  1. I may not understand you correctly, but you may have a number of misconceptions regarding viral surfaces. A couple of points: - virus envelopes are typically formed by elaborate protein structures and they do not have a membrane as such - these proteins have complex three-dimensional structures (as other proteins) and often require additional proteins to be folded correctly and can be decorated - as such, the interplay between different viral proteins (and host mechanisms) are required to give viruses their final shapes - the immune response is dependent on the recognition of specific shapes (epitopes) - producing a viral part in vitro does not guarantee to provide the correct shape to recognize a life virus In addition, as mentioned you have to make sure that whatever you use as a vaccine does not induce harmful events. So again, just pulling proteins from a sequence and then releasing it into the bloodstream does not easily work, rather it would need quite a long process to make sure that it works and that it is not harmful. On the other points, eukaryotic cells do have free ribosomes but are also part of the rough ER. There are various options for RNA delivery including liposomes. That being said, I think while there are quite a few clinical trials for mRNA vaccines, they have not been approved yet (but some are fast-tracked).
  2. Just adding a random virus protein does not guarantee a useful immune response, and it can also cause adverse effects as mentioned. In quite a few cases it is necessary to modify the virus capsids in vitro in order to make them useful as vaccines. In vitro synthesis of viral particles can result in quite a different structure than in vivo, but for the latter you need to isolate and propagate the virus. Moreover glycosylation can make them difficult to be recognized and conversely, viral particles injected in significant amounts can lead to adverse inflammatory responses. mRNA only needs to be delivered to the cell. The nucleus is not the area where translation happens.
  3. No, the idea is to have mRNA coding for viral structure expressed by the host and presented as an antigen. Just synthesizing a random viral part in vitro usually has very low success rate. You do not know whether the part elicits a suitable response, nor can you always ensure that whatever you synthesize has still its native form. Even worse, injecting it in relative high concentration can also have adverse effects without actually conferring immunity. That is why when you start designing a vaccine you often have to work with the intact virus and either design around an attenuated form or, if you can, isolate a workable part. But that requires time. Even then, if a good target is known the big time consuming step are the trials. In extreme cases there are accelerated trials where requirements are relaxed. Nonetheless you still need to show that it actually helps. And just sticking a random viral structure in and hope for the best is unlikely to work.
  4. Well, that is why it takes a while, you'll need to figure out what components create an immune response, but you also want to avoid unspecific inflammation and other adverse effects. The last thing you want is healthy folks suffering from the vaccine especially in a case where the disease is still found to be of relatively low lethality. That being said, the fastest development route are probably RNA vaccines, which can produce targets basically overnight. However, safety and efficacy trials would also need to run.
  5. And on top of that, the differences are not what are typically considered to be "typical" dimorphisms (i.e. there is often substantial overlap between sexes). Also, it is difficult to correlate any neural morphologies with altered functions, which is why there are actually only rather few tests where we see reliable differences. And even there, the effect size is often not terribly huge. As mentioned, training could presumably close these gaps which makes it difficult to assess what features are truly sex differences in the biological sense. That is not to say that there are none, but given the plasticity of brains it would be strange to assume that especially abstract abilities would result in such pronounced differences as expressed in OP. To wit, I would take any bet that if I provided a female group with access to information, education and training while growing up while depriving the same to a male group, it won't be the latter who will figure out how to design a car or rockets first (note: don't do that, it won't pass ethics review). The point about subjective vs objective does not make any sense whatsoever, btw.
  6. Also timeisthe5th.
  7. CharonY replied to Skepticoid's topic in Biology
    Oh no, there are huge repositories that you can freely access so that is generally not an issue. Even if your specific species is missing you can at least take the closes assumed relatives and work from there. Also, when you sequence something new and publish it, you have to make to submit it to one of those public databases.
  8. CharonY replied to Skepticoid's topic in Biology
    As briefly mentioned, it all depends on what type of analysis is being conducted. If for example we use a species-specific marker that is not found in the species under investigation, we would not be able to amplify anything, resulting in basically no result. Similarly, DNA can degrade or be contaminated to such a degree that we will not obtain data, either. However, if the DNA is of sufficient quality to be amplified, either restriction analyses or sequencing will allow you to assess relationship to known species via phylogenetic reconstruction. There is a paper by Sykes et al. (Proc Royal Soc. B, 2014 281:1789) in which they analysed hair samples which were attributed to e.g. Yetis or similar organisms. After thorough de-contamination they sequenced a part of the mitochondrial DNA and found that they were actually from a wide range of mammals. Samples attributed to bigfoot were found to be cow, coyote, deer, black bear, horse, racoon and human, respectively. Two samples matched a fossil record related to current polar bears.
  9. CharonY replied to Skepticoid's topic in Biology
    So species identification is a very specific application and there have been techniques developed based on hair-snaring. A typical genetic target are conserved mitochondrial sequences, which can be obtained from hair samples even with few or no follicles attached (though yield is better if one gets more cells with them). In the past one would do restriction analyses (in short: amplify region with PCR, digest the amplified DNA sequence and look at the resulting pattern to compare with known species), though more commonly nowadays the amplified locus is sequenced and compared to a reference database (often also called DNA-barcoding). Even if the sequence is not found, one can use conserved sequences to build a so-called phylogenetic tree. There, the sequence in question would be quantitatively compared to existing ones and based on similarities one could figure out how the unknown species is related to known ones (i.e. if it is a close relative, for example). As long as a conserved locus is used (such as e.g. cytochrome C oxidase you will always get relationship info (i.e. it would not return as unknown). One issue could be contamination by other species, but as long as you can get some clean reads out of the sample of interest, it is often possible to isolate the novel from contaminating ones. That is a part of the problem, many TV shows, especially those who are more sensationalist usually do not care much about proper reporting. There is a decent chance that a) all they got is something mundane, such as regular wildlife and reporting it as unknown just sounds more exciting, b) they contaminated their samples and mostly got DNA from their producer who handled the samples inadequately but did not have the budget to repeat the whole thing or c) they got data, but did not bother to ask an expert to interpret it or d) they used a different method, but would require some elaboration.
  10. CharonY replied to Skepticoid's topic in Biology
    Essentially there are a range of DNA tests in use. To test familial relationships for example one can amplify certain DNA regions of DNA and compare them to references e.g. from the parents. If you submitted a different species, you obviously would not get usable results. In other words, the type of DNA tests are highly specific, depending on purpose and will have to be designed differently for each application as well as species. I should also note that the vast majority of these test are not based on sequencing, but mostly rely on a form of genotyping. I.e. one monitors genetic variation at a given chromosomal location.
  11. CharonY replied to Skepticoid's topic in Biology
    In addition to what others said, you can get mitochondrial DNA from hair; it depends on what types of analyses you want to run.. It depends on the type of assay. The vast majority of DNA testing is performed on diagnostic regions and comparison with reference data sets. But the actual loci as well as the database being used would define what you can or cannot identify. The description does not provide enough information.
  12. Well green tea generally should have a yellow to brown colour but if you are using crushed leafes in tea bags (which I feel should also banned for green tea) they can extract much faster than loose leafs.
  13. How about a livefeed? I could put it in a screen and watch while pretending to listen to students!
  14. I would like to add that evolutionary psychology is suffering from a number of issues, and is one a the forefront of the replication crisis. Many of these issues stem from ill-defined research questions (to which I would include OP). Originally, the premise was fascinating, and there have been successful studies. However, many aspects in human evolution in this field are based on extrapolation, which are often not based on solid evidence. As such, a lot of these studies may be just-so stories. As a result solid science is mixed with heavy storytelling and the latter unfortunately dilute the former.That is not to say that the field is useless, but rather it is still a field trying to figure itself out. The worst thing is probably the fact that the interest in these studies are not in line with the level of evidence they can provide. Pop culture often takes tentative studies as ultimate validation of some long-standing assumptions and stereotypes.
  15. Yeah, he was (never seen in him in person, just interviews) and certainly one of the greatest voice actors.
  16. Not sure why but this little tidbit stuck with me: in "What's opera, doc" Arthur Bryan was Elmer's voice ( "Ritt der Walkueren" is forever linked to "Kill the Wabbit" in my brain) . Two years after release Bryan died and was buried in Valhalla Memorial Cemetery.
  17. Yeah, I lost my nerd license to my wife, so I know how it feels.
  18. I think you'll have to return your nerd license and re-apply.
  19. So, what's up, doc?
  20. CharonY replied to iNow's topic in Politics
    Well, there will be folks voting for mayonnaise, because it is more relatable. Spoiled or not.
  21. I have not seen any of the publications of that institute in mainstream journals. Most references I found where in more obscure psychology journals. That does not necessarily mean that they are not doing research, but they do not seem to be huge contributors. The titles I have seen appear to be make claims that are quite outside of what current science is able to tell us.
  22. So that is an interesting claim that I have not hear before. I am aware that chimpanzees are predators of other animals and that they are also prey to some large predators (there quite a few studies out there describing e.g. defensive strategies against leopards). . There are also observational studies that, as you implied, deadly intergroup violence has been reported, often the actions of small groups of male chimpanzees. However, while persistent, the occurrence is very low , even when their territories are very small due to human actions and in cases of limited resources. I am not sure whether leopard predation rates are higher (considering that they are also getting extinct). However, considering the overall rarity it does not make it terribly likely that it is a significant selective pressure. Considering the constraints on chimpanzee habitats, it is not unlikely that their population density was lower than early hominids and probably also hominins. I stand corrected. However, considering the lack of usage in our cousins it does seem to imply that weapon use may have developed relatively late in hominid evolution, though. So if we move away from innerspecies violence, there is apparent evidence for predation ca. 1.9 million years ago. That, IIRC has been associated with access to more proteins and improved brain development (or at least it has been speculated as such). Bipedalism on the other hand most likely evolved ca. 6-7 million years ago. Predating the increase in skull size by a fair bit. I do not believe we do have tools older than ~4 million years ago, so these various developments (bipedalism, tool use for feeding, tool use for hunting, skull size increase) seem to have occured in waves. Though certain aspects are likely to have affected subsequent developments. I.e. bipedalism could have freed up hands for tool use.
  23. That is an interesting hypothesis, however to my knowledge there is not a lot of evidence of weapon use. The oldest identified tools were pounding tools, mostly associated with food acquisition and preparation. I doubt that there is sufficient evidence to properly assess selective pressure due to predation or competition for that time frame. The oldest artifact that could be considered a weapon of sorts was found ca. 280,000 years ago, a spear tip which was presumed to be used for hunting. But this is of course way later than when bipedalism occured. That at least make a direct co-evolution of these factors not very likely (or at least there is little evidence for it),
  24. And yet I think that just assuming things to be right, even if they are not, is what prevents us from getting anywhere. Most projections assume that the population is likely going to stabilize beteen 9,6- 12.5 billion. Meanwhile you are assuming impossible numbers, use conspiracy theories to support your point. That, however, is not helpful in developing strategies. If you plan for a population that may never arrive, you are not planning for the right thing. Also, since you do not understand the connection between fertility and education (especially women's education), it means that you are missing out that in high-fertility countries increasing the standard of living and increasing women's education may be stabilize the world population at the lower end of the prediction. In other words, if one wants to make a proper risk assessment and develop appropriate strategies, the most important bit is getting familiar with the actual situation and look at mechanisms that are relevant to them. Bold assumptions without any evidence is helping no one.
  25. That is because you do not understand the relationship between standard of living and children choice. First, try observation. Look at family sizes in industrialized countries. Then look at families with high educational standards. What is more common there. a family with 9 children or family with 2? Then take a look at less developed countries and look at family size there. This is a well-known phenomenon because in areas where children are important as labour and to secure generational stability (e.g. as labour and to care for parents) and with high infant mortality a higher birth rate is expected. Once other opportunities arises (social welfare system, broader job market etc.), and medicine improves (reduced infant mortality, availability of contraceptives) , folks start making decisions whether they want offspring or not. Especially when women become more educated and want to have careers, they decide to have fewer or no children. In other words, your model of population growth is too simplistic and takes only survival into account, but does not reflect reality.

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