Covid19 science
Discussion
Armchair Expert said:
Our government has advised us that there is little point in wearing masks.
However surely any mask is better then no mask?
Even if a mask is 50% effective that must substantially reduce your chances of getting the virus which isn't really airborne?
There is a bit of a conspiracy going round, it's because we simply don't have enough masks for everyone so gov just said don't bother. They are mandatory in some post corona countries? No idea if there is anything in it.However surely any mask is better then no mask?
Even if a mask is 50% effective that must substantially reduce your chances of getting the virus which isn't really airborne?
Rosscow said:
Maybe it's because it's more important that people that really need them get them, rather than Joe Bloggs walking down the road?
Though Joe Bloggs walking down the road right now should not really be happening unless it falls into one of the recently announced categories I would thinkSimpo Two said:
But there are many cases unreported, or untested, and some people can have it with few or different symptoms. So I think the actual ratio is much lower.
I agree the death rate could be lower, though 1/100 is towards the low end of the range of estimates, certainly less than most recorded ratios. However, going back to my calculations, if we go below 1/100, that means far more people have been infected than the one million. It makes meeting people not a good idea!Peter3442 said:
I agree the death rate could be lower, though 1/100 is towards the low end of the range of estimates, certainly less than most recorded ratios. However, going back to my calculations, if we go below 1/100, that means far more people have been infected than the one million. It makes meeting people not a good idea!
Outside of cities imho people are not meeting. Very quiet here out in the sticks and anyone out walking is giving other people a wide berth. I was in a pharmacy queue t'other day and every person was 2m apart etc etc.TX.
For the mathematically inclined (simultaneous partial differential equations!) a Numberphile video on free Geogebra software that models Covid19 infection rates and lets you play with the variables.
https://www.youtube.com/watch?v=k6nLfCbAzgo
https://www.youtube.com/watch?v=k6nLfCbAzgo
Posting on another thread about SK's approach diverted here.
.
How SK did it
Only 10 minutes to trace contacts
My short within blog-comment thread exchange with a resident Search for colin to find it.
Data sharing and tracking of people seems key. Legislation enacted due to the SARS/MERS situation of a few years ago to allow temporary suspension of specific GDPR/privacy type stuff at such times to enable.
.
How SK did it
Only 10 minutes to trace contacts
My short within blog-comment thread exchange with a resident Search for colin to find it.
Data sharing and tracking of people seems key. Legislation enacted due to the SARS/MERS situation of a few years ago to allow temporary suspension of specific GDPR/privacy type stuff at such times to enable.
How does virus & antibody testing work?
Are there multiple levels depending on the quantity, i.e. new virus small quantity the swab goes to a lab to be grown then looked at under a microscope by a highly trained scientist vs. known virus big quantity there is some chemical marker that can be used?
What are the varying levels of accuracy and do they tend to err on producing false negatives or false positives?
Are there multiple levels depending on the quantity, i.e. new virus small quantity the swab goes to a lab to be grown then looked at under a microscope by a highly trained scientist vs. known virus big quantity there is some chemical marker that can be used?
What are the varying levels of accuracy and do they tend to err on producing false negatives or false positives?
grantone said:
How does virus & antibody testing work?
Are there multiple levels depending on the quantity, i.e. new virus small quantity the swab goes to a lab to be grown then looked at under a microscope by a highly trained scientist vs. known virus big quantity there is some chemical marker that can be used?
What are the varying levels of accuracy and do they tend to err on producing false negatives or false positives?
https://www.bbc.co.uk/news/health-51491763 - polymerase chain reaction to amplify trace DNA in the sample then a chemical test to match part of the chain. Viruses are too small to see with any conventional (optical) microscope.Are there multiple levels depending on the quantity, i.e. new virus small quantity the swab goes to a lab to be grown then looked at under a microscope by a highly trained scientist vs. known virus big quantity there is some chemical marker that can be used?
What are the varying levels of accuracy and do they tend to err on producing false negatives or false positives?
The current test seems prone to false negatives
False -ve with PCR is likely to be due to the use of mouth and nasal swabs.
Easy to get a poor sample, particularly if the patient moves away during sample taking.
Blood would be much more accurate, but it's not as easy to scale up for mass drive through testing.
If you get it done, stay still while they tickle your tonsils.
Easy to get a poor sample, particularly if the patient moves away during sample taking.
Blood would be much more accurate, but it's not as easy to scale up for mass drive through testing.
If you get it done, stay still while they tickle your tonsils.
GroundZero said:
The virus itself is coated with a layer of fat, which is why washing hands is very effective. The soap quickly breaks the fat layer down exposing the virus inner core which can not survive and also can not settle within the body.
Makes me wonder if there could be a simple mask that could be made that filters breathing air through a soapy barrier. Won't protect the eyes of course but could bring the virus spread rate well down below 1.0.
Good point to make regarding improvements to the design of the masks, though seem to think the 3M N95 or FFP3 masks already do a pretty good job. The soap idea would of course kill the virus off for good as would bleach, but that's probably not so good for the wearer to breathe in.Makes me wonder if there could be a simple mask that could be made that filters breathing air through a soapy barrier. Won't protect the eyes of course but could bring the virus spread rate well down below 1.0.
Bearing in mind that the biggest risk to inhaling the virus is when wandering around inside a building or enclosed space such as a train where there are lots of people crammed together and minimal vented air space then perhaps add virus protection into the heating, ventilation, and air conditioning systems (HVAC) in these areas by adding in some form of centrifuge effect to the airflow so the virus is spun onto the walls of the unit which are coated in soap or bleach, etc. whilst the clean air travels down the centre and recirculated because there is no mass. There are already loads of small centrifuge filter units available for purchase on Amazon and eBay, so surely they could be modified and scaled up.
One other thought, does anyone know whether UV light kills the virus because if this is the case then perhaps the solution is to add in UV booths to walk through and add into HVAC systems, these additions won't stop the spread of the virus but they might slow it down. Am pretty sure UV light units have been used for quite a few years to kill bacteria in water pipes.
mike74 said:
I don't understand the science behind how it survives for considerably longer on hard surfaces compared to softer absorbent surfaces, you'd think on the softer more absorbent surfaces it would be less exposed to the elements and able to survive longer?
IIRC any fluid carrying the virus is absorbed leaving it high and dry. Which it doesn't like.mike74 said:
I don't understand the science behind how it survives for considerably longer on hard surfaces compared to softer absorbent surfaces, you'd think on the softer more absorbent surfaces it would be less exposed to the elements and able to survive longer?
Resuspension or transfer on touching is easier from a smooth surface. There probably is an absorption effect going on, but also more opportunities for interactions that hasten the decay of the virus on a non-smooth surface. Also, apparently, dies off relatively quickly on copper vs steel/plastic. viable virus still present after 72 hours for steel and plastic, copper no viable virus after 4 hours which is shorter than cardboard (24h) so as I said there are probably other effects going on, could be the copper interferes with the virus to break its surface somehow? I don't 'do' bugs so there are factors I'm not familiar with, but with any contaminant it is easier to spread more on a smooth surface and also to lift it off again to put it in the air, that is something I am familiar with.
[ref: Aerosol and surface stability of SARS-CoV-2 (Covid-10) as compared with SARS-CoV-1. NEMJ correspondence 17/3/20. National Institute of Allergy and Infectious Diseases, Hamilton, MT]
https://coronavirusexplained.ukri.org/en/?_ga=2.22...
Recently launched and clearly still a work in progress, but some structured information and links to the papers behind the info.
mike74 said:
I don't understand the science behind how it survives for considerably longer on hard surfaces compared to softer absorbent surfaces, you'd think on the softer more absorbent surfaces it would be less exposed to the elements and able to survive longer?
I can't find a definitive explanation, but maybe the spikes of the virus's outer coating stick better to soft fibres with irregular surfaces than hard smooth metals or plastics. Some would get damaged when it broke free, and the virus would be less/un able to penetrate, your cell membranes.llewop said:
could be the copper interferes with the virus to break its surface somehow?
Numerous studies on copper and its effects on combating viruses.It was noticed many years ago that many of those those that work with copper, either mining it or working with it don't seem to become infected with many viruses that go around.
GroundZero said:
Numerous studies on copper and its effects on combating viruses.
It was noticed many years ago that many of those those that work with copper, either mining it or working with it don't seem to become infected with many viruses that go around.
taIt was noticed many years ago that many of those those that work with copper, either mining it or working with it don't seem to become infected with many viruses that go around.
something like that was in my mind, certainly that copper has some interesting chemical interactions that could explain it.
Gassing Station | Science! | Top of Page | What's New | My Stuff