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Everything posted by dttom

  1. May I not focus on emotion, I rather consider it a form of neurological result, but other neurological effects like sensation, memory,etc shall have equal ranking. Now you are talking about inputs, of many forms, but ultimately translated into nerve impulses, bringing about various neurological effects. I shall say in scientific sense, energy is used in the transfer process, nerve impulses are energy-demanding. But I am open to other intepretation that 'energy' may refer to other things in metaphysical or philosophical senses. Then, when you consider if emotion, or other neurological effects are permanant, probably you go into the issue that if that neurological effect contribute to memory, may it to be remembered, or be involved in memory, both are possible. And I believe it is also possible to have forms of effect which will be completely recover, so it does not leave trace.
  2. I heard from a lecture of major occurrance of Down's syndrome in female, but when I check for verification I found male to female ratio at 1.3 to 1. So maybe something wrong there, but this leads me to think about why one sex will be more susceptible to some genetic disease like chromosome 18 trisomy. Any suggestion?
  3. dttom

    about DNA ?

    To have what you said done, the piece of foreign DNA should be integrated into genome (how to get in cell? how to be integrated?), the chances are very low especially without homologous sequence for homologous recombination; even if it comes in, it will mostly be a mosaic instead of a genuine organism with all genomes identical.
  4. dttom


    This is actually I encounter when I am doing an exercise. Now there are 2 phage mutant but we don't know if they occur at the same locus. The usual practice is to conduct a complementation test (to cross them in a restrictive host and see if lysis occurs). But, because it is provided that this phage is T even and replicate with headful packaging (genomes concate and every capsid accomodates 1 genome plus some more bits), my question is why can't we use a permissive host to do the job. Let say if the two mutations occurs at the same locus, in a permissive host no matter how they perform recombination they cannot produce wildtype phage, so that when the progeny is spread on a restrictive lawn, there is no plaque expected. The result should be different if they occur at different loci that, recombination or headful packaging might result in a wildtype genome which then gives rise to plaque. For different loci mutation, wildtype could be generated, in my own idea, by: recombination: A--B' x A'--B --> A--B (WT) + A'--B' headful packaging: A--B' + A'--B --> A'--B--A--B' (concatemer)--> A'-|-B--A--|B' (1 unit + bits, of WT) But my instructor says my method cannot tell between 'two loci mutation' and 'single locus mutation', the exact phrasing is: "No matter if the mutations in the tested mutant phage strains are in the same gene or in different genes, the mutant phage strains can co-infect the (permissive) host cells, and their genomes can recombine to generate the wild-type phage progeny in such an assay." which I don't understand, can anyone help? Any would be helpful, thanks. [solved, thanks]
  5. In yeast two hybrid (Y2H) system, binding domain (BD) and activation domain (AD) of GAL4 protein are separated and linked to heterologous protein. Besides the protein structure of BD-AD, I have also heard of BD-repressor domain structure. The problem is I don't know of any example, could anyone suggest some?
  6. your prof should be referring to the amount of genetic material instead of chromosomes.
  7. It depends on what type of infectant you are concerning about.
  8. That means you got the insert but you cannot sequence it because it gave you just a 600bp piece? Then you may use another primer to continue the work, better to have some regions in overlap with the first 600bp, then you will get your first 600bp, and a second piece of another 600bp with some overlap so as to enable arrangement of fragments.
  9. Well, the protein consumption should be approximate to the body composition, that if 25% of the body is made up of protein, just take the approximate amount of your total calory intake, in this way the protein could be better utilized to prevent excess or deficiency, after all they are broken down and assimilated eventually. Whether or not excess protein gives fat depends on the amino acid, but on average a protein molecule should contain most of the twenty amino acids in the body so usually it is true that excess protein could put more fat. But I don't think it is significant if you compare this effect with that of excess carbohydrate consumption. And not all excess amino acids end up in fat but to depend on whether it is a ketogenic (finally to fat) or glucogenic (to glucose) or both.
  10. dttom


    Because the chance to select a driver on bus A is different from the chance to select a student in bus A, so two expected values should be different.
  11. So if it appears purple, should it absorb much of the purple light? Apply this question to its complement color and you get the answer. I think you may not provide a definite wavelength but a range.
  12. Think of circumstances when you want to mount a bacteria dead or alive.
  13. I don't think you can find mp or bp of other ions like the common ones, Na+ and K+. You should be looking for compounds.
  14. Actually I am looking for plasmids containing MV-H and MV-F, I surf companies' website but could not find such a product. I need them because I am planning an experiment related to measles H and F mediated cell fusion, all other materials are ready except this pair of plasmids. So is there any suggestion where I can find them. Or if there is any scientists here, could they kindly provide some for me? Thanks.
  15. looking for... surface tension?
  16. dttom


    I don't understand your first question. Try to think about electronegativity of S and Se for your second question.
  17. So you may begin with calculating number of mole of substances produced per reaction, and calculate how many reactions have been performed.
  18. I am just a bit confused about whether we should use a truncated value in calculation, personally I think the answer should be 'no' (as multiple rounding-off or truncation adds uncertainty), but I just want a confirm. Say for example, I worked on raw data and got an eqation of: y = 0.784x(plus or minus 0.002)+0.059(plus or minus 0.008), so here 0.784 and 0.059 are truncated values based on the standard deviation (0.002 and 0.008). Now if y is 0.224, shall I use the raw values (that is, the original values not truncated) or truncated values of 0.784 and 0.059? If if use the truncated ones, then, 0.224 = 0.784x+0.059, x=0.210(3 sig fig). I just feel a little bit weird not to use numbers provided in an equation but to trace back to their (the numbers') origins. Because two methods give different result, I just want a check, thanks for any help.
  19. electrolysis of molten KCl.
  20. I am not sure, but is it about if a mutant clone is temperature-sensitive, say growth inhibited at 37c, it could still grow quite well at 25c, so when you meet a clone that is nearly absent at one temp but present at another, it implies there might be some mutation in cdc?
  21. I am not sure if I call the topic 'linear regression' is right, actually it is about 'least square analysis' in constructing a best-fit line, but when I googles the phase 'linear regression' some relevant information pops out. So assuming now we have a set of data, y values correspond to x values; plotting it in y vs. x manner it appears to form a straight line, but now we want the best-fit line. The method is to select an m value and a c value, by y = mx + c, to minimize di = sum[(actual y)-(computed y)]^2, I can do this step. What I got difficulty is to find the standard deviation of m and c. Sy^2 = di/(n-2); In a lecture I heard about: Sm^2 = (Sy^2)(n/D) where n is the observation size and D = nsum(Xi^2)-(sum(Xi))^2 and; Sc^2 = (Sy^2)(sum(Xi^2)) I do not know how these equations are derived. There is no explanation in the lecture as it simply uses them in applications, while I am interested in the derive-process. I googled it and some suggested Sm^2 = (Sy^2)(sum(dm/dyi)) ===partial differentiation, similar formula is for Sc^2 by replacing dm/dyi with dc/dyi. Again I do not know how they are derived. Could somebody help?
  22. It is 2cm in March 03 and 16cm in September 07, so the interval should be in years, not just 10 months...
  23. How would you do that? I'm sure you don't mean burning the tyre and allow photosynthesis to do the rest.
  24. I can't qutie follow what you mean, but I don't understand why you calculate the growth rate per year in (16-2)/10 (where the '10' comes from).
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