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I saw these two illustrations in the article Glycine: and I don't understand what are the differences between these two structures. If it's the same molecule why they are different while using skeletal structure?
93.126.88.30 ( talk) 00:07, 5 December 2016 (UTC)
Thank you. I know what is zwitterion but I'm not talking about the plus and minus signs that make it zwitterion. I am talking about the structure. It says that there are here TWO types of skeletal structure with different positions with different number of elements (H3N vs.NH2) 93.126.88.30 ( talk) 02:11, 5 December 2016 (UTC)
Here in Australia, the rules state that a male cannot donate blood for a full 12 months after engaging in anal sex with another male. Many have argued that such a long period is unnecessary - it could be reduced to three months with no risk (feel free to disagree if I've somehow got the science wrong). The "window period" for modern HIV tests is never longer than that, as far as I am aware, and in many cases is shorter.
two questions:
1. Less important question: Would there be any safety risk to the blood supply in terms of avoiding HIV transmission, by reducing the exclusion period after male-male sex from twelve months to three?
2. This is my more important question: How much would such a move practically increase the donor pool? I would assume that the majority of men who have anal sex with men (I avoid the term "gay", as not all such men would identify with the title) would generally not do so on a one-off, or only once a year. Men who engage in this activity would, in general, I assume, tend to do so on a regular basis (i.e. significantly more frequently than once every three months). I know many answers here will be speculative, but I still believe it's a fair question: How many men are excluded by a one-year exclusion period, who would not be excluded by a three month exclusion period? How much of an impact would such a move have on donor numbers and blood stocks? Would it be significant at all? Or would it be trivial, making any rule change have little practical impact?
I don't think any of the answers to this question would potentially fall into the "medical advice" prohibition, as those who make the rules on these matters are at zero risk of taking advice from wikipedia! And the second question is not really a "medical" one in any case. Eliyohub ( talk) 09:57, 5 December 2016 (UTC)
(EC) I found [1] which I think is the most recent review of the behavioural based donor deferral criteria in NZ. It mentions a 6 month deferral was considered but rejected based on what was felt was insufficient evidence that it wouldn't increase the risk. It also mentions other things like why more detailed sexual history (e.g. condom usage) was rejected (again insufficient evidence and what limited evidence there was caused concern as well as concern over whether such questions may be too invasive), why oral sex is included, etc. One thing it does mention is that the older 5 year period was at least partially due to concern over new TTIs. However it doesn't sound like the 12 month period was based on that.
I make no comment on the decisions and accuracy of the information contained in the report, except to note that it says the maximum window period is for hepatitis C which is 94 days. While it doesn't seem there's good evidence sexual activity is a strong risk for hepatitis C infections (except for certain co-occuring infections), since there is some limited evidence it may be the case that a conservative risk assessment would consider 3 months too short. The report does mention that in addition to the window period + margin of error for the test just in case, there is also concern over making the margin of error too short in case people don't remember correctly. Note it would seem easily possibly relying on people to remember if they've been properly (including all courses) remember if they've been vaccinated against Hepatitis B would raise similar concerns although I'm not sure if this arises since it doesn't seem Hepatitis B has the worst window period, e.g. Human T-lymphotropic virus 1 also has a longer window period.
Also the report makes it sound like in some countries (but not NZ anymore) there may be concern over a failure to remove a sample with a positive test result (quarantine failures/release errors). While improving systems to prevent this would be the primary goal, in the mean time reducing detected infections (by removing riskier individuals) may also be implemented to reduce the risk of TTIs, and this was evidently part of the reason for the old 5 year deferral.. Finally the report does mention 6 months was recommended by the blood service in Australia but rejected by the TGF. It is also was implemented in Japan and maybe elsewhere (I didn't look that well). I suspect you can probably find some info on why the TGA rejected the 6 month deferral. It also seems likely that if research in those countries where 6 months was adopted suggests it didn't result in an increase in TTIs, this would be then spread, as the report and other things I've read suggest this is what happened with 12 months.
Nil Einne ( talk) 14:38, 5 December 2016 (UTC)
Nil Einne, thanks for your answer. Two issues. One, re vaccination for Hepatitis C B, there is no need to rely on donors correctly remembering if they've been vaccinated - testing for "surface antibodies" will give this info as to immunity entirely accurately, as I mentioned in an earlier reply. I had such a test myself, for reasons unrelated to blood donation. My understanding is that such a test is no more expensive than a standard Hepatitis B test, and is in fact done by some clinics as a standard component of such tests.
Second, is there any info as to either a) What percentage of the male population have had sex with another man during the last 12 months, but not during the last 3 months, and b) did the cutting of the waiting period in Japan and any other jurisdictions which implemented it lead to any increase in donations? Eliyohub ( talk) 13:12, 7 December 2016 (UTC)
I understand—from both the Wikipedia article and the Wiktionary article—that the word mitochondrion is constructed from the classical Greek for "thread" and "granule." My question is, why thread and granule rather than, say, potato and tennis racket?
I can guess that a mitochondrion's gross morphology may have stricken its discoverer(s) as particularly discrete and grain-like. I can also speculate that its strands of DNA may have stood out to the microscopically aided eye. But I know better than to trust my guesswork on a matter about which I am so far from expert.
Could someone please illuminate? And to clarify, although I do welcome guesses better educated than mine, what I'd really love is an authoritative explanation of what actually did inspire the namer, rather than merely what might plausibly have done so.— PaulTanenbaum ( talk) 14:08, 5 December 2016 (UTC)
I saw this video which is viral on Facebook and it claims that the way that people sit on the lavatory seat is not correct and not healthy and the correct way is like animals or as people used to do in the past (read the titles on the video). My question is if it's proved scientifically or it is nonsense? 93.126.88.30 ( talk) 15:43, 5 December 2016 (UTC)
Nice answers! thank you all 93.126.88.30 ( talk) 17:06, 7 December 2016 (UTC)
Arachidyl alcohol page isn't clear on this. Is this substance always derived from groundnut (peanut) oil? And if so, can it cause an allergic response in someone who has a peanut allergy? -- TammyMoet ( talk) 17:09, 5 December 2016 (UTC)
If the door's hot it's often said to tell the fire department where you are then seal cracks with wet towels. And breathe near the floor and through a wet towel if need be.
Would floating in a cool bathtub further increase the time before injury or death if the firemen take longer than average? Taking trash bag(s) of good air with you and only opening them to breathe? (exhale inside or outside the bag?) Holding your breath after you run out of air below a certain level of smokiness and hope they get there before you have to breathe again? What's the best breathing strategy? How smoky should the air become before holding your breath as long as you can becomes the best strategy? Sagittarian Milky Way ( talk) 19:15, 5 December 2016 (UTC)
How much fruit does a mature Ginkgo biloba produce in one season? Surtsicna ( talk) 22:08, 5 December 2016 (UTC)
“ | The seed of G. biloba contains a thin-layer nut, which is consumed as food and a medicine throughout the world. Fresh nuts contain about 41% moisture. Dry nuts contain 6% sucrose, 68% starch, 13% protein and 3% fat [27]. The commercial production of Ginkgo nuts has been reported in China for more than 600 years. About 44 cultivars with best performance in growth have been selected, based on quality, size and shape of their nuts and productivity [2] and [28]. These cultivars are propagated by grafting technique using seedling rootstocks. These grafted plants start bearing nuts after 5 years of age. In China, a widely grown cultivar, Dafushon, in Jiangsu Province, produces 5 to 10 kg of nuts by a 15 year old tree and between 50 to 100 kg by a 50 year old tree. One recent production from 700,000 to 800,000 trees produced an average of 6000–7000 tons of dry nuts per year [2]. | ” |
Non-Gingko meta discussion
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Science desk | ||
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< December 4 | << Nov | December | Jan >> | December 6 > |
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. |
I saw these two illustrations in the article Glycine: and I don't understand what are the differences between these two structures. If it's the same molecule why they are different while using skeletal structure?
93.126.88.30 ( talk) 00:07, 5 December 2016 (UTC)
Thank you. I know what is zwitterion but I'm not talking about the plus and minus signs that make it zwitterion. I am talking about the structure. It says that there are here TWO types of skeletal structure with different positions with different number of elements (H3N vs.NH2) 93.126.88.30 ( talk) 02:11, 5 December 2016 (UTC)
Here in Australia, the rules state that a male cannot donate blood for a full 12 months after engaging in anal sex with another male. Many have argued that such a long period is unnecessary - it could be reduced to three months with no risk (feel free to disagree if I've somehow got the science wrong). The "window period" for modern HIV tests is never longer than that, as far as I am aware, and in many cases is shorter.
two questions:
1. Less important question: Would there be any safety risk to the blood supply in terms of avoiding HIV transmission, by reducing the exclusion period after male-male sex from twelve months to three?
2. This is my more important question: How much would such a move practically increase the donor pool? I would assume that the majority of men who have anal sex with men (I avoid the term "gay", as not all such men would identify with the title) would generally not do so on a one-off, or only once a year. Men who engage in this activity would, in general, I assume, tend to do so on a regular basis (i.e. significantly more frequently than once every three months). I know many answers here will be speculative, but I still believe it's a fair question: How many men are excluded by a one-year exclusion period, who would not be excluded by a three month exclusion period? How much of an impact would such a move have on donor numbers and blood stocks? Would it be significant at all? Or would it be trivial, making any rule change have little practical impact?
I don't think any of the answers to this question would potentially fall into the "medical advice" prohibition, as those who make the rules on these matters are at zero risk of taking advice from wikipedia! And the second question is not really a "medical" one in any case. Eliyohub ( talk) 09:57, 5 December 2016 (UTC)
(EC) I found [1] which I think is the most recent review of the behavioural based donor deferral criteria in NZ. It mentions a 6 month deferral was considered but rejected based on what was felt was insufficient evidence that it wouldn't increase the risk. It also mentions other things like why more detailed sexual history (e.g. condom usage) was rejected (again insufficient evidence and what limited evidence there was caused concern as well as concern over whether such questions may be too invasive), why oral sex is included, etc. One thing it does mention is that the older 5 year period was at least partially due to concern over new TTIs. However it doesn't sound like the 12 month period was based on that.
I make no comment on the decisions and accuracy of the information contained in the report, except to note that it says the maximum window period is for hepatitis C which is 94 days. While it doesn't seem there's good evidence sexual activity is a strong risk for hepatitis C infections (except for certain co-occuring infections), since there is some limited evidence it may be the case that a conservative risk assessment would consider 3 months too short. The report does mention that in addition to the window period + margin of error for the test just in case, there is also concern over making the margin of error too short in case people don't remember correctly. Note it would seem easily possibly relying on people to remember if they've been properly (including all courses) remember if they've been vaccinated against Hepatitis B would raise similar concerns although I'm not sure if this arises since it doesn't seem Hepatitis B has the worst window period, e.g. Human T-lymphotropic virus 1 also has a longer window period.
Also the report makes it sound like in some countries (but not NZ anymore) there may be concern over a failure to remove a sample with a positive test result (quarantine failures/release errors). While improving systems to prevent this would be the primary goal, in the mean time reducing detected infections (by removing riskier individuals) may also be implemented to reduce the risk of TTIs, and this was evidently part of the reason for the old 5 year deferral.. Finally the report does mention 6 months was recommended by the blood service in Australia but rejected by the TGF. It is also was implemented in Japan and maybe elsewhere (I didn't look that well). I suspect you can probably find some info on why the TGA rejected the 6 month deferral. It also seems likely that if research in those countries where 6 months was adopted suggests it didn't result in an increase in TTIs, this would be then spread, as the report and other things I've read suggest this is what happened with 12 months.
Nil Einne ( talk) 14:38, 5 December 2016 (UTC)
Nil Einne, thanks for your answer. Two issues. One, re vaccination for Hepatitis C B, there is no need to rely on donors correctly remembering if they've been vaccinated - testing for "surface antibodies" will give this info as to immunity entirely accurately, as I mentioned in an earlier reply. I had such a test myself, for reasons unrelated to blood donation. My understanding is that such a test is no more expensive than a standard Hepatitis B test, and is in fact done by some clinics as a standard component of such tests.
Second, is there any info as to either a) What percentage of the male population have had sex with another man during the last 12 months, but not during the last 3 months, and b) did the cutting of the waiting period in Japan and any other jurisdictions which implemented it lead to any increase in donations? Eliyohub ( talk) 13:12, 7 December 2016 (UTC)
I understand—from both the Wikipedia article and the Wiktionary article—that the word mitochondrion is constructed from the classical Greek for "thread" and "granule." My question is, why thread and granule rather than, say, potato and tennis racket?
I can guess that a mitochondrion's gross morphology may have stricken its discoverer(s) as particularly discrete and grain-like. I can also speculate that its strands of DNA may have stood out to the microscopically aided eye. But I know better than to trust my guesswork on a matter about which I am so far from expert.
Could someone please illuminate? And to clarify, although I do welcome guesses better educated than mine, what I'd really love is an authoritative explanation of what actually did inspire the namer, rather than merely what might plausibly have done so.— PaulTanenbaum ( talk) 14:08, 5 December 2016 (UTC)
I saw this video which is viral on Facebook and it claims that the way that people sit on the lavatory seat is not correct and not healthy and the correct way is like animals or as people used to do in the past (read the titles on the video). My question is if it's proved scientifically or it is nonsense? 93.126.88.30 ( talk) 15:43, 5 December 2016 (UTC)
Nice answers! thank you all 93.126.88.30 ( talk) 17:06, 7 December 2016 (UTC)
Arachidyl alcohol page isn't clear on this. Is this substance always derived from groundnut (peanut) oil? And if so, can it cause an allergic response in someone who has a peanut allergy? -- TammyMoet ( talk) 17:09, 5 December 2016 (UTC)
If the door's hot it's often said to tell the fire department where you are then seal cracks with wet towels. And breathe near the floor and through a wet towel if need be.
Would floating in a cool bathtub further increase the time before injury or death if the firemen take longer than average? Taking trash bag(s) of good air with you and only opening them to breathe? (exhale inside or outside the bag?) Holding your breath after you run out of air below a certain level of smokiness and hope they get there before you have to breathe again? What's the best breathing strategy? How smoky should the air become before holding your breath as long as you can becomes the best strategy? Sagittarian Milky Way ( talk) 19:15, 5 December 2016 (UTC)
How much fruit does a mature Ginkgo biloba produce in one season? Surtsicna ( talk) 22:08, 5 December 2016 (UTC)
“ | The seed of G. biloba contains a thin-layer nut, which is consumed as food and a medicine throughout the world. Fresh nuts contain about 41% moisture. Dry nuts contain 6% sucrose, 68% starch, 13% protein and 3% fat [27]. The commercial production of Ginkgo nuts has been reported in China for more than 600 years. About 44 cultivars with best performance in growth have been selected, based on quality, size and shape of their nuts and productivity [2] and [28]. These cultivars are propagated by grafting technique using seedling rootstocks. These grafted plants start bearing nuts after 5 years of age. In China, a widely grown cultivar, Dafushon, in Jiangsu Province, produces 5 to 10 kg of nuts by a 15 year old tree and between 50 to 100 kg by a 50 year old tree. One recent production from 700,000 to 800,000 trees produced an average of 6000–7000 tons of dry nuts per year [2]. | ” |
Non-Gingko meta discussion
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