×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.
7

Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
For discussion of the primary matter of this thread, but the stubborn dissagreements can remain there.

https://www.eng-tips.com/viewthread.cfm?qid=483537

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I come away with the feeling that what the WHO does well, they do well.
When new information is presented, the WHO tend to regress into hubris and politics.

Does this sum up the content of the article accurately.
Many years ago, it was found that tuberculosis was spread by aiborn particle but that due to the method of which tuberculosis infected the lungs, only particles or aerosols smaller than 5 microns caused infection.
This is a characteristic of tuberculosis, not of aerosols.
Thus was born the erroneous 5 micron cut-off.
Now tests have shown that aerosol transmission of COVID is possible with particles up to about 100 microns.
Experiments have shown that aerosol transmission of COVID is possible with particles up to about 100 microns.
Physics has shown that aerosol transmission of COVID is possible with particles up to about 100 microns.
Airborne COVID virus can be spread by ventilation systems.
Dr. Fauci has accepted that aerosol transmission of COVID is possible with particles up to about 100 microns.
The WHO have accepted that aerosol transmission of COVID is possible with particles up to about 100 microns.
The research has shown that aerosol transmission or suspension in the air is possible for 100 feet.
I note with interest that the opposition to the new evidence comes from those who have not done any valid experimentation.
Everyone scientist who has looked at the experiments without bias or hubris has accepted that COVID is transmitted for up to 100 feet by aerosols .
Bottom line:
Wear a mask.



Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Thanks Bill... been wearing N95 masks since Feb of last year... and only go out once or twice a week for food...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

To be honest most doctors don't actually say the public wearing of surgical masks is anything to do with preventing the wearer from catching covid. Apart from a small help stopping them doing direct hand to mouth contamination off public unclean surfaces

They are to stop you spraying and contaminating everywhere if you have it but don't know it.

So it limits the aerosol dispersal because it hits the mask as you breath out.

The PPE gear they wear on the wards to prevent the staff catching it is a completely different kettle of fish.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
Yeah, if you're not working in a COVID hospital it seems the big non-vaccine fixes are source control (put a mask on for other people) and dilution (air changes and social distancing). Where I work, we went from masks and fairly strict distancing in the office to no masks is OK if you've had the vaccine. I don't know how many cases have originated at the office, we are not told.

Masking has been relaxed pretty quickly in NY state in general, following the CDC order that fully vaccinated people don't have to. So far, the number of cases in the US is going down.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
It does shine a light on how the science can get pretty deep pretty fast. One interpretation I took away from the article, is that the 5 micron limit was generalized from TB which requires a very small particle to get deep into the lungs and spread. Focussing on a different contagious disease would probably have lead to a different conclusion.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

measles is the big one where I am. TB also rears its head but its not in the same league as Measles.

Basically they want a glass window to isolate the person.

Quick google says that for 2 hours after an infected person leaves the room with measles an unvaccinated person has a 90% chance of catching it.

We are just about to reopen the offices and vaccinated is a requirement. If 1 person is not vaccinated then the whole office has to revert back to the distancing/mask reg's .

Its now a feature of all job specifications for hiring that the person needs to be vaccinated with at least the first shot and I suspect during interview they will be asked about when they are getting the second.

I suspect there will be a bit of a melt down soon with the anti vaxers because their lives are going to become very restrictive very quickly. And although its illegal to sack someone for refusing to get vaccinated the other restrictions make working next to impossible.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote:

To be honest most doctors don't actually say the public wearing of surgical masks is anything to do with preventing the wearer from catching covid.

Quote:

The PPE gear they wear on the wards to prevent the staff catching it is a completely different kettle of fish.
That's a bit inconsistent. Masks are not Maxwellian demons

Quote:

Apart from a small help stopping them doing direct hand to mouth contamination off public unclean surfaces
That's never been demonstrated to be significant risk for COVID

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
Measles was a disease from the history books for me (age 50+)until there was a critical population of anti vax people I think in Oregon starting a few years back.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Masks are still useful for source control, but for vaccinated people, the risk of being a transmissible source is much less.

Quote (CDC Science Brief: COVID-19 Vaccines and Vaccination Updated May 27, 2021 )

A growing body of evidence indicates that people fully vaccinated with an mRNA vaccine (Pfizer-BioNTech and Moderna) are less likely to have asymptomatic infection or to transmit SARS-CoV-2 to others. Studies are underway to learn more about the benefits of Johnson & Johnson/Janssen vaccine. However, the risk for SARS-CoV-2 infection in fully vaccinated people cannot be completely eliminated as long as there is continued community transmission of the virus. Link

Transmissiblity after Vaccination is still not a fully answered question, but the indications are better than hoped for.

Can You Still Spread COVID-19 Even After Getting Vaccinated? Here’s What We Know So Far The CDC released new information Thursday on the transmissibility of COVID-19 in vaccinated people. By Colleen MurphyApril 02, 2021

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Big question, how does the risk of being a transmissible source compare for vaccinated and asymptomatic persons?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Vaccinated and asymptomatic persons are reported to shed fewer if any viral particles. - It is a subject of current study.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

A lot of this stuff is what they have discovered for flu over the years. its as good a starting point as any.

Btw where I am there is no flu what's so ever this winter.

The STD doctors are also well happy with the pubs and night clubs all being shut for several months as their case load has dropped to fractions of the pre covid levels.

Here is the same with the measles as soon as the vac rate dropped below 75% they started having huge out breaks. They are thinking about making it mandatory for kids going to school.

Personally I don't know what the huge fuss is about wearing the masks. Its more of a social issue of the modern world of people objecting to being told to do anything for what ever reason and then bitching like hell they they were not told something when hind sight its discovered they should have been. Its a no win situation. There is no harm wearing them so I just do it.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

In Sweden we haven't had any mask requirements, in the beginning it was only for elderly homes and homecare personal and of course in hospital, intensive care since there t's not possible to keep the distans that was required for everybody else.
It is only now after new year it is needed in public transports.

They court on quite early that the infection risk was higher in IC units then in other places, which is due to the respirators needing pressurizing to get the air down to the lungs.
I guess this also makes the risk for air born droplets larger.

We have almost not had any of the other usual flues either, it was the same during the swine flue, people toke much greater care of washing there hands often and now also keeping the distance and staying home when feeling sick.
So that simple messures can go a long way is at least a good thing as long as people keep to them.

Same here the police haven't impounded as many weapons and narcotics in years as this last one, they have also taken allot more sex buyers, since they do not need to use there resources for drunk weekend scuffles or kerfuffle's.

I love that word , hi hi smile thanks pete.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

They are talking about vaccine only venues and schools here.

Which the anti vaxers are dead against.

The rest of us think its quite a good idea. Nothing to do with covid. It just gives us a place to go and send our kids without a certain type of person or parent of kid.

Win win as far as I can see.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Do you mean to wear a mask?

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

They are talking Vax passport for entry and cert for the kid to be accepted into a school.

Beginning of next month if a whole office is vaxinated then all social distancing and masks protocols are removed.

If even one person is not vaccinated then everyone has to comply with the whole lot.

It's going to be the same with public venues as well.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Tugboat offered a suggestion in the other thread that we should consult paint booths experts with regard to how to set up ventilation to control COVID transmission. This suggestion reminded me of the expert I have consulted many times.

Quote (https://portal.acgih.org/s/store#/store/browse/det...)

Industrial Ventilation: A Manual of Recommended Practice for Design
This has been my go to reference anytime I needed to know how to control dusts and vapors for an industrial process.

The American Conference of Government and Industrial Hygienists are experts in paint booths and all sorts of industrial exposure engineering controls. Here is a link to an older version https://archive.org/details/gov.law.acgih.manual.1....

They (ACGIH) have now published some COVID-19 Resources which are very to the point.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

FacEngPE,

Focusing just on the filtration negates anything that has to do with the virus getting to the proper cell receptors or more simply put being contagious.

I have wondered if running a humidifier is enough or has a huge affect on transmission. Transmission rates dropped after July and picked up in September/October in Texas and if there is a state with a huge population of virus deniers, it is Texas.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The paint booth engineer faces an interesting challenge. In their case the droplet needs to stay airborne long enough to make it from the paint gun to thr painted surface while the aerosol needs to either get exhausted or fall to the floor so it doesn't contaminate nearby surfaces.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

We hade a huge problem at our paint shop after someone else had taken over the running of the main building service.
They hade a lot of bad finish on the finished paint.
We use positiv and negative charge to get the paint to go to the "target".
After several month of investigations they reached the conclusion that the problem was that the building service department hade taken away all the humidifier from the ventilation system, so the air was full of all kind of particles when the air was dry, that was landing in the paint before it was dry.
And it might even be so that to dry air also effected the paints ability to find it's way to the "target" I think the paint is positively charged and the target negativ.
Not that would have any impact on a virus though.
So they hade to install new separate humidifiers there, with a control system keeping the humidity constant all the time.
I do not know at which level but I would guess around 45-50%.

And something totally of topic, I was looking for some info on this paint thing and found a promising link to a pdf.
And when I open it, it's a big picture on the frontpage with my CH.
It always hit you the hardest when you do not expect it, especially when he hated being photographed and I would never hade expected finding a photo of him on the web.

BR A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Anna, What's "CH"? I understand who you're talking about - just don't recognise the abbreviation.

A.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

It's the first two letters in his first name or the first of first name and first of his family name.
Ch. H he was always so private, I guess I still have it in me.
Even came across his Facebook page a couple of month back, almost never uses FB myself, you would not have know he was dead, that was also very strange.

This calculated evaporation curve might shead some light Fischstabchen it's not exactly the same conditions but it shows some interesting effects.

The relative humidity of the air is kept constant at 50%



How that is, can be read here.

https://www.ht.energy.lth.se/fileadmin/ht/Kurser/M...

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I probably do not think that evaporation has much to do with the spread of the infection either.
If someone coughs or sneezes and there are drops of all possible sizes, those that are too large do not have time to get much smaller before they have fallen to the floor or some some other surface.
So only those with less than 100 microns can possibly fly around if that's the limit.
In that case, the question is whether they have time to be airborne for so long that they have time to be affected by evaporation before they get stuck on some solid object.
Ordinary solid particles or dust that are dry can be stirred up from draft and air movement even after landing on a surface.
Not sure that it applies for this Covid-19, I think that as long as it is most it can stay alive, when it dries out it dies.
And how much of what you cough sneeze or exhale is less than 100 microns if that's the limit?

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I have a gut feel that although crude my fart "taste test" is a reasonable indicator....

And the medic's I know who are mostly orthopaedic don't really have many arguments against that rule of thumb.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I think that the point is first finding the source of the 5 micron limit, and once identified, trying to overcome the inertia to have the more realistic 100 micron limit accepted, and to have the protocols adjusted accordingly.
The science has been made pretty clear.
What is distressing is the refusal of so many people, both in the street and in medical administrative positions, to even consider that what they originally were taught was not a universal truth.
The reason for the 5 micron limit applys only to tuberculosis infection and not to aerosols/drops in general.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Bill if you had ever done bioengineering you would understand the issue.

Medics hate engineers

I did FEA on hips and knees for a while and then got asked one day to go in and watch a spinal fusion implant because they kept on failing after 2 years, target 8-10.

I watched the surgeon cycle plastic bend a bit of titanium 4 times putting it into the neck. On the fourth bend I told him to scrap it.. All hell let loose, I said you can't do that with titanium... he said why not... physical properties its not aluminium. Give me a material that can... if I could the way you want to handle it I would get Nobel prize... How many times can I adjust it? 2 max... and that was the end of my bio engineering career.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Yes i think they changed there approach for Covid-19 just to be on the safe side.
Here they only went from 2 meter to 2,5 meter distance and forbid the use of table fans and fans in elderly homes to keep the heat away.
They still say they have not seen any real evidence of that this virus is what they call air born.
No spread have been detected in places where people are far apart but many visits every day, like shops and stores.
I think maybe the UK variant is a bit different it seems to spread easier.


Saliva contains of 95,5% water, and we know it's density, how much the virus weighs and how much heavier it can make a droplet or it's abelite to be air born is also a unknown.
After all it has one of the longest RNA strands they have seen.

Best Regards A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The 5 micron limit for TB probably has much to do with larger contaminated particles being filtered out rather well by mucus. Possibly mucus covered TB is not very infectious.

If it turns out that mucus covered covid is infectious, then the 5 micron to 100 micron particles are still in play even after they are captured by our natural mucus filtration. This might be related to "receptors" or the integrity of the package in mucus.

ACGIH is more about the entire system of things used to control workplace contaminates than just filtermasks.
  • Masks don't provide rated protection unless fit tested, and put on per the tested method. (each person needs their own fit test)
  • Guiding the contaminate away from you is better than filtering it out at your nose.
  • Control is easier at the source than using bulk space ventilation.
Masks have been found to be effective at controlling "sources" probably due to even poor filters being able to catch fresh wet sticky drops in a humid air stream easily.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I got TB as a kid by drinking unpasteurised milk...

I believe thats the main source in the UK of getting it.

Where I am now its public transport that its mostly traced back to.

Measles seems to be in the same city in a two day period and unvaccinated and if you get it they are not surprised even if there is no traceable contact.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Since one of the effects of the virus and they also know why it happens is that some looses there taste and smell.
So it infects the area in the nose where the smelling sensors are, so obviously it can sustain it self in that environment,
The most healthy and fit seems to have been getting it worse, getting infected in the lungs.
Here they have sade from the beginning that you couldn't get infected by eating something that hade it on it, never heard any one claim that it happened either.
The sickest person we hade, who survived was in intensive care sedated for three month, he was a firefighter.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

It only takes ten TBC bacteria to get infected,
In a single sneeze there can be 40,000 infectious droplets (0.5-5 µm in diameter).

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

That's why I think masks that are anything but 100% effective are useless for preventing infections. With viruses, technically it only takes one successful infection of a cell to cascade into illness. Obviously the odds are small but a mask that reduces droplets by 50% when there are tens of thousands and it only takes a few droplets to cause infection.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The mask is meant to catch those 40 000 droplets, its not meant stop you breathing it in.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Respirator Rating Letter Class
N - Not oil resistant
R - Resistant to oil
P - Oil Proof
Respirator Rating Number Class
95 - Removes 95% of all particles that are at least 0.3 microns in diameter
99 - Removes 99% of particles that are at least 0.3 microns in diameter
100 - Removes 99.97% of all particles that are 0.3 microns in diameter or larger. HE or HEPA quality filter.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I picked up 200 that were rated KN95 which I understand is similar to N95.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote:

The mask is meant to catch those 40 000 droplets, its not meant stop you breathing it in.

So, don't kiss someone wearing a mask... lol

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Another difference between TBC and COvid-19 is that TBC is a bacteria it multiplies by dividing, it does not need get inside a cell to do it, and the immunsystem can't take care of it.
That's why it needs so few as ten to get infected.

If you got ten Covid-19 viruses in your mouth, nose or eyes, the chance of one making it to a cell to be able to reproduce is much smaller I would think.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (TugBoat)

That's why I think masks that are anything but 100% effective are useless for preventing infections. With viruses, technically it only takes one successful infection of a cell to cascade into illness. Obviously the odds are small but a mask that reduces droplets by 50% when there are tens of thousands and it only takes a few droplets to cause infection.

So the only choices are 100% effective or completely useless?!?
I see you brought your typical level of nuance to the subject!!!

Let’s say every inhaled virus particle has 0.001 probability of infecting you.
Then probably of not getting infected by one inhaled virus particle is 0.999
If you inhale N particles during a given interaction (N is proportional to product of inhalation concentration and staytime) then the probability of not getting infected during that interaction is 0.999^N (to not get infect after N particles, then each must not infect you, and we assume non-infection probabilities are independent).

So:
P(not getting infected)= 0.999^N
P(getting infected) = 1 -P(not getting infected) = 1 - 0.999^N
Plot this curve vs N below. Notice the following:
  • For N < 500 it is a very linear increase. 50% reduction in concentration can decrease your risk by almost 50% in this region. Our risk reduction is comparable to the minimum filtering efficiency of our mask
  • For N > 5,000, the probability of getting infected approaches 1 constant, so a low rate of increase. You are almost certain to get infected and 50% reduction in concentration probably won't help much in this region
So whether a given intervention that reduces N by 50% is worthwhile during a given interaction depends to some extent on where N starts out on that curve.
I saw a paper that drew such curve (can’t find the link) and made the case that we are in the linear part of the curve in the vast majority of interactions (there are very few interactions where you are almost guaranteed to catch the virus with near 100% probability). Here's my example curve using my arbitary 0.999 number, I don't recall the numbers in the paper. Also you might consider N as either virions or virus-laden respiratory particles, each requires some assumptions especially in the independence.




=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

TugboatENG,

You aren't trying to catch the virus but whatever the virus is attached to. In addition, the severity of the illness appears like a lot of viruses to be dose dependent. A lot of these medical personal who died I believe did because their initially exposure was so severe. People used to inoculate people with small pox by having them sniff ground up scabs from someone with small pox up their nose or run a single thread with blood from someone with small pox through an open wound. Of course, sometimes people still developed full blown small pox but it was at a much lower rate. I suspect that mask, even if not 100% effect, might be providing a similar effect or in the least reducing the severity of the illness.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The continued argument about masks not protecting the wearer simply flies in the face of logic and common sense. Regardless of the what the actual efficacy is, under any given circumstance,, be it 50% or 90%, it's better than breathing raw air, period.

https://www.preprints.org/manuscript/202007.0613/v...
https://ncceh.ca/documents/evidence-review/basics-...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

"An accurate quantitative estimate of the infective dose of SARS-CoV-2 in humans is not currently feasible and needs further research. Further work is also required on the relationship between routes of transmission, infective dose, and outcomes."

This is where we are at. We simply don't know. It's reasonable to question any assumptions at this point.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

4
TugboatENG,

You could say the same about near anything and the pandemic would come and go before the science has come to a firm 100% conclusion. There is evidence that shows a correlation between dosage and severity and this is common among many viruses. I don't know of what evidence there is that counters this even if it is presently just a hypothesis.

I get tired of this continual rant about what the science has confirmed and what is unknown. If I was working with some chemicals that had unknown carcinogenic effects but there was lot of evidence that suggested it was carcinogenic, I would suit up with proper PPE regardless of what has been confirmed. This pandemic has literally fleshed out those who would just keep doing as is instead of prepping for what could be. It is like keeping on driving while their car makes loud funny noises because it could be something minor instead of bringing the car in to a shop. It is the anti-thesis of precaution and safety and in a forum full of Professional Engineers, whose duty is to protect the safety of the public, it is a little unexpected.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Truth be told most of the protocols are actually naval 1700 quarantine requirements.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (TugBoat)

This is where we are at. We simply don't know.

#1 - So are you now saying you simply didn't know when you said "That's why I think masks that are anything but 100% effective are useless for preventing infections. " (?)

#2 - Referring to the model I provided above, we do have the ability to draw some conclusions about where our interactions might lie on the curve, even without rigorous infectious dose estimates. We can simply note that we have had many encounters and yet (for most of us) we never got covid (as verified by any testing that we've had done). If we had even one interaction a day during the first year, then that's 365 interactions, and if none of those interactions resulted in infection then it's a darned good bet those encounters were on the left side of the curve (near proportional reduction in risk with filtering efficiency) rather than the right/flat side of the curve where infection is near certain.

I'm fully on-board with saying we should all be humble about how well we understand this thing. It applies to the scientists and it applies doubly to us laymen. I wish you would move in that direction.

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

It's hard to say we had many encounters. Even at the peak case load the number of identified cases was still less than 1 in 1000 of population in the USA.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

It's a good clarification, not every trip out of the house brings you in direct contact with an infected person.

But a lot of the time (grocery store, at work, etc), there is not just one person in the space but a large number of people in the space. And you are not only faced with the people that are in the space at the same time as you, but also the people who may have been there in the last hour or two (potential settling time for aerosols).

And each person is infectious not only for one day (in which case infectious fraction would be same as case number fraction) but likely for 2 or 3 days and as much as a week.

With all that said, not all people are the same. Some people at certain points in time are identified as superspreaders much more infectious than average. Certainly if you spent several quality hours getting cozy with one of those superspreaders in their prime spreading window, then I'd agree you're probably on the right side of the curve where the 50% mask would probably not have very much effect on an almost-inevitable infection. On the other hand, if you happen to walk briskly past that same superspreader at a distance of a few feet, then I'd think you'd definitely want to have that mask on for the best odds.


=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

it was way higher than that in some places Tug... one state up north had 3500 in 100 000 at one point. Which did make me wonder why they were bothering with vaccination within 12 weeks they would have hit 75% anyway.

I think the super spreader having a mask on would have more effect than you wearing one.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I am not sure what exactly is the definition of a so called super spreaders?

In Sweden I seem to remember that it was used about a man that had infected many.
But this was at a large birthday party.
So if there was a lot of mingling and hugs during several hours, of course many would be infected.
It's not the same as if someone actually spreads more viruses with one breath when breathing then others.

The size of the virus is diameter 0,05 to 0,14 microns and it can vary in length with +0,009 to 0,012 microns (I think they mean the spikes here, it was called the tumors).

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

"superspreader" can apply to an event, or to an individual, and also to an individual at a specific point in time when his virus shedding peaks
https://www.laboratoryequipment.com/573221-The-3-F...

Quote:


According to the study results, published in PNAS, 50% of individuals with less than 650 BMI-years exhaled “significantly less aerosol” than the half of the group with more than 650 BMI-years. Essentially, the elderly, the obese and the obese elderly are at a heightened risk of transmission. Conversely, study participants younger than 26 and those under 22 BMI were all found to be low spreaders.

Within the high-producing group (> 156 particles/L), 18% of individuals accounted for 80% of the exhaled particles. The distribution follows the 20/80 rule seen in other infectious disease epidemics, meaning 20% of infected individuals are responsible for 80% of transmissions.
I'm waaay more than 650 "bmi-years". Good thing I'm vaxxed.

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

That's good info Pete. It highlights California's diversion from science as they keep schools closed.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

TugboatEng,

The U.S. has been way over 1 positive case per 1000 people. After it burned through NYC, immunological studies were putting the percentage infected at around 15%. 1 out of 1000 people in the U.S. is about 330,000 people and NYC had more than that by itself. Maybe, you are going by some positive test survey but immunological ,which check for anti-bodies, paint a much starker picture. If I were to guess based on the number of people I know that tested positive, I would say that about 20% of the population has had it. If you agree that the death rate is around 1%, we are at 600,000-700,000 officially dead from COVID-10 so you are looking at around 20% by that number.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

In TugBoat's defense, his comment was reply to mine in the context of how many times would a mask be challenged to defend you from coronavirus. So the relevant number for that particular comparison would not be cuumulative cases as a fraction of the population, but infectious cases at a particular point in time as a fraction of the population. Given 2-3 day infectious window, I'd think that would be around 2-3 times the daily cases new expressed as fraction of the population.

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I was commenting on the number of active cases, not the total. What is the likelyhood of coming into contact with an infected person in a day?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Tugboat,

Active cases have been way more than 300,000 or 1 out of 1000. If you buy that 20% of the population has been infected, you are looking at over 60 million people in the U.S.. We are bout a year into this but 60,000,000 / 60 weeks puts you at 1 million a week if it was evenly spread, which it wasn't.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Masks
Almost any kind of mask - except the ones with exhale valves were found in practice to be good at preventing infected persons from transmitting to others.

Quote (https://www.acgih.org/covid-19-fact-sheet-worker-r...)

  • With a cloth face covering (Cloth FC)…75% inward leakage and outward leakage.
  • With a surgical mask… has 50% inward leakage and outward leakage
  • With an N95 filtering facepiece respirator (FFR) 10% inward leakage and outward leakage. If fit tested to individual persons can approach 1%.

During the early part of the pandemic, my wife had the occasion to see an ER hospitalist that also worked as a virologist helping to design my employer's covid response.


N95 and P100 filters are available for these, I think he was using the P100 (99.97 percent efficient against 0.3 micron DOP.)

The point here is that high performance filters only provide high grade protection when they are not bypassing air due to poor fit. Most of us had no opportunity to fit test.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Today Worldometer is reporting that 1 in 10 in the US has or has had COVID.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

With the relatively low fatality rate and high number of deaths, I'm going to have to agree with Fisch and say that the number of infected is likely closer to 1 in 5.5

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

they are basically checking every blood sample in the UK now when it hits the labs for antibody's and also gene sequencing every covid test. But its months after the sample is taken before they have the full picture.

But they are not making a lot of noise about it I presume because they don't want someone taking them to court and stopping them and/or putting a load of data restrictions on them. They are not per say recording who has what immunity just if a person has it to see what the community values are.

They are also testing most sewage systems for viral load as apparently they can see what the viral load is of the covered area is. Again the data and fact they are doing it is not broadcast.

It will be 2-3 years though before the big picture is documented and published.

As for the contact stuff I lived in a social bubble of 2 family's which everyone tested positive apart from me. I wasn't wearing a mask and was cuddling a sick 5 year old for 18 hours straight because only daddy would do....

from reading about it my blood Group O neg might have been a factor.

Plus I had something strange in Jan when it all started. The female colleague that I have blamed for catching it off objects quiet strongly to being called a super spreader.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

BMI-years new unit?

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Body mass index, pretty old and controversial as a single-valued gauge of obesity https://en.wikipedia.org/wiki/Body_mass_index
BMI-years, not new, a measure of excess weight and years carried https://www.ncbi.nlm.nih.gov/pmc/articles/PMC35243...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Its like dog years

If your a fat chuffer like me, then you get some years added so you can work out how near you are to the average death age.

COVID though has been hitting diabetics quite hard and as fat chuffers are more likely to be class 2 diabetic even if they don't know they are class 2 yet or are in the pre stage some have been using this BMI age as an adjustment for working out what mortality group they are in.

Due to me getting medicals every year my blood sugar increasing was spotted years ago and I have been able to adjust things to not get labelled as class 2 and be subjected to that hellish drug metformin.

Most people because they don't get tested every year end up only finding out when there blood sugar is through the roof and they have a lot less options and their body's have been going through hell for years trying to deal with it.

I write this post as a self confessed fat chuffer so don't anyone be getting upset about body shaming comments all comments in relation to being fat are about myself.



RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

BMI has the advantage of being a simple number - easy to determine, and statistically correlates with some health situations that are deemed important. On an individual basis it is imprecise, and therefor useful mostly as a screening tool, but often provides incomplete or impossible to follow recommendations.
For BMI labeled obese (almost everyone over 40 fits this category), dieting is not necessary helpful for some of the health items that correlate. Aiming for a stable weight is likely helpful for most of us.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Okey I knew about BMI it was a bit of a hype here 7-8 years ago.
There was also a lot of blood testing "health control" at work checking, blood pressure good and bad cholesterol and things, it was voluntary.
We even had this 10 year checkouts 30, 40, 59, 60 by the healthcare system I think it was a project not shore they still do it though, I was never called last time.

But I never heard the expression BMI-years.
Seems to me as a difficult unit, to relate to if you don't keep track of your BMI and good/bad cholesterol ratio level every year.

Not even sure I understand why BMI-years would have anything to do with who is a super spreaders.
Do they have better lung capacity then children or atlets and can produce air born droplets that is spread further then others?
Or do they produce more saliva?
Or less saliva?
Do they bread more often?
That small kids is less infections at distance is clear since they are shorter have smaller lungs less airspeed when breathing out.

Might add I have just half read electricpetes artikel, but making a study about super spreaders with that as a starting point / base line feels odd and it was only done with 194 individuals so I am not sure how accurate it is.

ponder

/A



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (IRStuff)

BMI-years, not new, a measure of excess weight and years carried https://www.ncbi.nlm.nih.gov/pmc/articles/PMC35243...

Just as a point of clarification, that is excess BMI years.

The article I referenced in PNAS (an initialism, not an acronym!) defined their usage of BMI-years in their opening as just a simple multiplication (nothing to do with excess)

Quote (PNAS)

Our findings indicate that the capacity of airway lining mucus to resist breakup on breathing varies significantly between individuals, with a trend to increasing with the advance of COVID-19 infection and body mass index multiplied by age (i.e., BMI-years)

BMI at/below 18.5 is underweight, so if you're 35 years old you'd need to be underweight to be below this 650 BMI-years.
At my age 60, I'd need a BMI around 11... not much more than a skeleton.

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The correlation in the article, while significant, is pretty iffy to me; there appears to be lots of caveats buried in the reasoning. They had a lot of people with BMI*yeara above 1600 that were low spreaders.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Yes I agree the correlation in figure 2 is not overwhelming. Although it seems to show that superspreaders are rarer and not as super among those with less than 850 bmi-years.

The reason I cited the article was in response to question whether individuals (vs events) can be superspreaders. That is shown somewhat in figure 1A (A is the upper left graph) where you see a very few on the far left emit waay more particles than most people. I think this particular study only looked at respiratory droplets (not viral content) so there may be other viral shedding factors that vary among individuals.



=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Sure, probably not that different than people who spit more than others when talking; that was one reason one dim sum restaurant finally got their servers to wear spit shields

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

More then iffy.

They say

Quote:

We qualified as “low spreaders” those 159 individuals who exhaled below 156 particles per liter.
We evaluated relationships between exhaled aerosol particle number and sex, age, and body mass index (BMI). No correlation was found with sex, while significant correlations were observed between exhaled aerosol, age, and BMI—and particularly BMI-years.

They do not show any graf for only age or only BMI.
This BMI-Year graf only contains 146 test persons since the rest haven't left data to be in it.
And if you draw a line at 156 particles per liter.
And then take away every super spreader that has one or more low spreader in the same BMI-year.
There is only one super spreader left at 2300 BMI-year!
Hardly a statistical proven result with 146 test persons.
I would say this is total nonsens.
Or am I missing something?



Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I don't think that's the way they did the partitioning. The BMI correlation only applies to a small group of people designated as "superspreaders."

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

There was 159 persons that exhaled bellow 156 p/l and 35 super spreaders over, a total of 194 test persons in this study.
The graf contains 146 test persons since they hadn't the right data to make the BMI-year calculation for the rest.
Red triangle = super spreaders = 25 counted
Black dots = low spreaders = 121
There is more people in the graf then 35.

There is no natural correlation between years an BMI to begin with so why make a Unit BMI*years, it does not make sense.


/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Rather than significant linear correlation, I think what the data shows more clearly is a significant threshhold effect.

If you raise the horizontal red line (minimum threshhold for superspreaders) to about 250 particles/liter, then you can count 12 superspreaders above an 850 bmi-years cutoff and 0 superspreaders below. This is in spite of the fact that about (almost) half the sampled population is below 850 bmi-years. If it were random (probability of superspreader independent of BMI-years), then the probability of a superspreader falling above 850 would be the same as the probability of falling below (0.5). So the probability that 12 just happened to all fall on the right side (similar to flipping heads 12 times in a row) is 1/2^12 ~ 0.00024 or double that for two-tailed distribution 0.0005. So I think there is something there. My analysis would not pass the world of hypothesis testing (even if there were half below 850, which there aren't quite) where you have to define the criteria before you look at the data (I picked the horizontal and vertical threshholds only after looking at the data) so if I were to claim p=0.0005 for the hypothesis that that superspreaders (defined by a 250 threshhold) are more likely above 850 than below, that would not be a legitimate claim (maybe they'd call me a "p-hacker", or worse). Nevertheless it seems a very noticeable threshhold pattern to me.

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Does not help every super spreader above the line can be taken out with one or more below in the same BMI-year.



/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Yes, that's the horizontal line I wanted (thanks).

What they're trying to show are the characteristics of superspreaders. They are not particularly trying to characterize the entire population.

If I draw a random person from the general population, what is the probability that he is a respiratory-particle superspreader? We can answer that question better if we know the BMI-YRS. In particular the aspect I mentioned was:

P(Superspreader | BMI-YRS > 850) >> P(Superspreader | BMI-YRS < 850)

I agree with you the original wording in the article seems off especially talking about (linear) correlation

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

There are two regression lines one for superspreaders and one for lowspreaders. What can be said is that if the two top superspreaders weren't there, there wouldn't be much of a correlation for them

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

What they sade was that

Quote:

We note that all volunteers of <26 y of age and all subjects under 22 BMI were low spreaders of exhaled bioaerosol.

But you can't really se that from the graf, maybe that is whas annoys me.

They could as easily had sad that everybody with a 26 years x 22 BMI = 572 BMI-Year can be a super spreader.
They obviously have one at 475 that person does not fit any of the above.
And 850 can be a 34 year old with BMI 25.

So I am not shore what conclusions that can be made.
There is a lot factors left out.
Have they even written what the youngest and the oldest was?

Or maybe it is that this Unit isn't used in Sweden, can't find it if I am looking for it in Swedish.

BR A



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I can’t say I ever ran across the unit BMI-yr before either.

Why they chose to emphasize BMI-yrs over separately examining BMI and years, beats me. I would assume that maybe the correlation and/or threshold behavior was no more evident in the individual BMI and years data than in the combined BMI-years data (if not there would be merit to splitting it).

I will mention, the only reason I cited the article was to defend the idea of superspreader person (see figure 1A).

But another interesting thing is these authors POSTULATE that the higher respiratory droplets from old and obese people might be part of the explanation for their worse outcomes when infected (the “promiscuous” droplets are supposedly more likely to find their way into the lungs). And perhaps it’s another factor making nursing home outbreaks worse.

Quote:


The strong correlation observed here between advanced BMI-years and greater propensity to generate respiratory droplets (Fig. 2) may be significant in the light of the recognized risk of those with high BMI (18, 19), advanced age (20), or both (21) (the elderly, the obese, and the obese elderly) developing severe symptoms upon COVID-19 infection. Promiscuity of respiratory droplets in the airways heightens the probability that upper airway infection transports deeper into the lungs, promoting severe symptoms, as is observed, with remarkable speed, following intranasal and intratracheal instillation of SARS = CoV-2 in NHPs (22). It also heightens the probability of expelling the aerosol into the environment and transmission of the disease, underlining the transmission risk of living circumstances that bring high-risk (high BMI-year) populations into close proximity for extended periods of time, such as nursing homes.


=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Fat cell have ACE2 receptors for COVID-19. I suspect the hypothesis of the author is that the weak immune systems of old people and people with a lot of ace2 receptor location ,fat people, are more likely to spread the virus due to more likely reaching a higher viral load due to a quicker replication of the virus and/or a weak immune response. Early in the pandemic, there was talk of using staton drugs to latch onto the ace2 receptors and slow viral replication.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I suspect they were clutching at straws. Linear regression is sensitive to extrema, so BMI*yr potentially moves some datapoints around enough to get the 0.98 regression coefficient. Nevertheless, the fit is pretty awful, and correlation does not equal causation.

Even worse, I think they fudged the data. I digitized the superspreader datapoints and got a similar regression line, but R^2 = 0.0884, which is essentially no correlation. Image I used and spreadsheet attached. I used https://apps.automeris.io/wpd/ to digitze


https://files.engineering.com/getfile.aspx?folder=...
https://files.engineering.com/getfile.aspx?folder=...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

https://www.diabetes.org.uk/about_us/news/new-wors...

From personal experience my morning glucose reading is 5.9 mmol/L not great but sort of acceptable, its stable and down to dawn effect.

When I had the first shot of vaccine it went up to 8.5 for 4 days.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (IRStuff)

I suspect they were clutching at straws. Linear regression is sensitive to extrema, so BMI*yr potentially moves some datapoints around enough to get the 0.98 regression coefficient. Nevertheless, the fit is pretty awful, and correlation does not equal causation.

Even worse, I think they fudged the data. I digitized the superspreader datapoints and got a similar regression line, but R^2 = 0.0884, which is essentially no correlation. Image I used and spreadsheet attached. I used https://apps.automeris.io/wpd/ to digitze
Cool digitization tool. Yes, I believe your r^2 =0.0884 a lot more than their r^2 = 0.98. And yet this is a peer-reviewed article in a prestigous journal (PNAS - an initialism, not an acronym). I can't help but wondering if we're missing something somehow. Too bad we can't ask the authors to explain how the heck they came up with their number.


=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Having two members of the family with PhD's in the bio stuff I suspect it won't pass an engineer's sniff test on data spread.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
They might have used the 'rejection of outliers' trick.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The only thing that is clear to me is that anyone older then 25 years old or with a BMI over 22 can be a super spreader.
2/3 of the population in most countries would probably be in this group.
Since there is people in the same BMI-year that are and are not super spreaders, I have a hard time to see what benefits there would be in showing it with a Unit like this.
A 65 year old with BMI 25 (normal) would be at 1625 BMI-years equally a 40 year old with a BMI 40.

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Is the colloquial understanding of "Super Spreader" still acceptable?
A Super Spreader Event: A large public event such as a political rally or a sports event with no mask mandate or social distancing protocol. May be called a Super Spreader event.
A person who organizes or causes such an event to be organized may be called a Super Spreader.
A person who has unknowingly contracted COVID and continues to socialize while ignoring mask and social distancing protocols may be foolish.
A person who knows that they have contracted COVID and continues to socialize while ignoring mask and social distancing protocols may be characterized as a Super Spreader.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Super spreader has other meanings in Scottish referring to a female....

And high BMI is not a problem to your average Scottish bloke. More by lack of choice than anything else with the local lasses

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

If you like to hear my comment, come to the pub, I will tell you.
Wellcome back Alistair!

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
Wink wink, nudge nudge

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I get a lot of BMPs of curves where we need to get actual numbers, so this tool has been a serious improvement. The only issue I have now is that people don't always use sufficiently contrasting colors in their graphs winky smile

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Your comment reminded me of this:
Link
Thanks to dgallup for posting the original back in 2019.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (Your comment reminded me of this:)


Reminds me of the guy that got onto an elevator with a well endowed lady, and the last thing he remembers is her saying, "Press One."

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

The latest variety it's pretty nasty

R rate in UK way over 1 again.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

(OP)
That's sad. I heard the 'try and give everybody one shot strategy' is working pretty bad against the new strain. The 'buy up all the vaccine and bribe the reluctant' strategy seems to be working well in the states.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

There is folk who have had both shots plus the two weeks starting to die.

It was stupid not restricting flights back from India

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

What do you mean starting to die? The daily deaths for the entire UK are in single digits. Those are good numbers.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

There is people who have had double shot over two weeks ago dying of covid again.

Not many but with the r rate well over 1 it's expected to rapidly increase again

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

They are warming up the nightingales again in the UK plus overstocking O2

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

> The 'buy up all the vaccine and bribe the reluctant' strategy seems to be working well in the states.

I'm not sure about the "buying up" part but the "bribe the reluctant" part is not working so great (graphic below from here). If you consider people with one dose as an indication of recent progress, we're not doing so well recently. There is a very strong anti-vaccine sentiment among certain segments and I have seen it firsthand in roughly half of my coworkers. I have mentioned in another thread it seems likely to me that we will see a UK-like surge here in the US within a month or two. I'll be watching uk closely as indication of what might be coming here, hoping their surge is not too bad.







=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

I have heard that UK needs to hit 85% one dose.

They are into the difficult sections of the population now so expect the first numbers to go way down.

Truth be told UK was about to implode but then the army logistics and medics did there thing and a load of extremely sweary none commissioned officers got given the task of "fucking sort it" which is what they are brilliant at.

I got jabbed for gulf 1 and three army combat medics did 600 of us in the space of 4 hours. With a mid wife as the emergency response medic. We didn't even stop moving when they stuck it in us. The pub was open at 2pm. The mid wife was three sheets to the wind by 1pm. Only one person had an issue but a glass of red wine dealt with that.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (Alistair)

There is people who have had double shot over two weeks ago dying of covid again.
Is there any indication whether this is people that the vaccin didn't "take on" or not.
The vaccin only gives 93 to 95 % of people vaccinated immunity both for Pfizer and Moderna and it's lower for Astra, J&J.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

> Truth be told UK was about to implode but then the army logistics and medics did there thing and a load of extremely sweary none commissioned officers got given the task of "fucking sort it" which is what they are brilliant at.

"implode"... do you mean the medical people giving the shots were overloaded? (we have no shortage of people to administer shots in the US... we just have a shortage of arms to receive the shots).

Btw Alistair, what EU country are you from?

=====================================
(2B)+(2B)' ?

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

It was logistics and the rules.

Army have a raft of vehicles and drivers that have a 24h/7 contract.

Civi licensing and transport rules don't apply to army

We used to do organ transfers two squaddies a class A hire car and a fuel card and we could do Glasgow Great Ormond Street in 4 hours a civi couldn't.

When we did it during the night we only dropped below 100 twice most of the time it was 115 mph plus pedal to the metal.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

He is from Scotland.
That's why I can't understand him, half the time. winky smile
Just kidding, love your expressions Alistair.
I learn something new everyday. thumbsup2

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

As for the personnel apparently it was an issue to begin with. The NHS was overloaded, they had all these nightingales hospitals but no staff for them.

They said that everyone had to do a series of courses which were your standard bum covering HR type stuff and also they were wanting the full contact with children checks done. Which takes a month normally. If they were doing it through the NHS trusts

There was dentists having to do 40 hours of CBT in there spare time just to spend the weekend in the mass vaccination centres. And as for the child security check it just looked stupid as they were in the age 60 plus getting vaccinated period. It was similar for retired nurses and Doctors willing to help. They wanted them to have the full up to date paper work pack.

There is some legal allowance to allow military medics of all grades to practise in the NHS. So combat medics go and do shifts in Accident and Emergency and the like and they don't have to do all the HR box ticking.

Anyway they solved the issue and the matter disappeared, quite what legal fiddles occurred I have no clue or if the military exemption was used. It was about the same time that the logistic issues disappeared as well.

The above is not fact, just what I saw over the period. I have a gut feel that the military joker was played to get round a few red tape hurdles. But I could be wrong and they actually changed the red tape.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Quote (moon161)

That's sad. I heard the 'try and give everybody one shot strategy' is working pretty bad against the new strain.

We'll find out over the next month.

What I've been hearing (various sources) is that the UK's cases are about 90% delta variant and we (Canada) are around 25% and increasing. We're somewhat ahead on first doses and I suspect (can't prove) our first doses are somewhat more evenly distributed in the population ... UK seems to be adhering more strictly to age groups for vaccine distribution. I'm not sure where their threshold is now but it probably means they've got few teens and twentysomethings vaccinated. This report https://www.publichealthontario.ca/-/media/documen... (which is a week or so behind the real situation on the ground) shows the age group coverage in my province. (See figure 3) - Even teens have single-dose almost 50% coverage taking into account that this is about a week behind. The 18-29 group ought to be over 60% now. First-dose protection against delta variant evidently isn't all that great but it's better than nothing, and it reduces the chance of ending up in hospital from it.

The problem is that second-dose coverage is only around 10%, mind you, that's mostly health-care workers, people with certain health conditions, and the over-80 age group, so fingers crossed we've got the worst risks covered, and second-dose coverage is increasing fast. The big question is whether it increases fast enough to stay ahead of the delta variant.

We've still got public health measures in place. Indoor retail only opened up yesterday at greatly reduced capacity, and indoor restaurants are off limits. No crowds at outdoor sporting events, indoor is off limits, kids are learn-at-home the rest of this school year.

Anecdotally - aside from a small number of known deniers/antivaxxers, everyone that I know has had one dose and some have had their second ... I haven't had my second yet. The deniers/antivaxxers are small in number but have an extremely high noise level.

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

Here in Sweden, the government has very few opportunities to exercise restrictions if they are not already written into law, so most of them have been recommendations.
The government have been able to request that the police uphold some already in place laws, that actually have other purposes than reducing the spread of infection, for example dissolve crowds.
But then only if it is considered an illegal demonstration, if people only meet to socialize they can do nothing.

The military may not be used for civilian purposes except in certain exceptional cases and on request.
So when they managed to introduce pandemic laws, now at the beginning of the year, there were too few people to check that they were complied with.
But it was solved to some extent by bringing in other professional categories for this, for example, they used animal inspectors, who are trained veterinarians, to check that restaurants and outdoor cafes maintained the distance and sanitation requirements and closing times.
I guess inspecting livestock or pub visitors may not be a big difference. winky smile

The military had trained a lot in setting up vaccination posts especially in the outer regions where it is far to larger cities and they were just waiting to get a request, do not know how it actually went.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure to recognize when an aerosol isn't a droplet, but without the stubborn dissagreements.

In Sweden the deniers/antivaxxers are small in number and far in-between and they don not have a media platform.

I have heard one or two saying they want get vaccinated.
One was and old friend, she actually have had Covid-19, she hade bought into allot of the propaganda in the beginning.
I told her flat out you need to read up properly on that stuff, you are much smarter then that, and go get your shots.

The only uprising was around the AstraZeneca vaccin.
But I do not think that, that is the same as believing your DNA will be altered or that you will become magnetic if you get vaccinated.
With the AstraZeneca vaccin there where at least some facts involved.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close