Brexit, for once some facts.

Danidl

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Masks, again...

Vallance said evidence in favour of masks protecting public 'marginal but positive'

Back in the health committee Vallance is now talking about masks.

He says the evidence suggests that, in terms of preventing wearers from spreading coronavirus to others, the evidence in favour of masks or face coverings is “marginal but positive”.

In healthcare settings there is a strong case for masks, he says.

He says when people are outdoors, the risk is generally low.

But he says there are circumstances in which masks can be useful. He says the risk of infection at one metre away from an infected source is 10 to 30 times higher than at two metres.


Surely the really obvious thing to do is mandate them for people who come into contact with lots of people, and advise them for most of the rest of us?

For example, the meeter/greeter/security people in supermarkets - ducking and diving round all the incoming and outgoing customers. Indeed, in general, staff have interactions with many people even at two metres.

A single hairdresser might manage, what, six people in a day? A till operator might manage that every five minutes. If the person is extremely infectious, and we know of historical super-spreaders of various diseases, the effect of a mask on the propagation by one checkout person could be huge.
I think he is slightly over egging the pudding. My calculation suggest on the simple inverse cube that doubling the distance makes at least an 8 fold reduction...and I gave you all the benefit of my calculations. If the spray is gravity driven,then it becomes even more distance friendly..and multiply by.An inverse exponential reduction .. exp(-x/z).. with Z the horizontal distance a spray travels from nose to ground, X the distance apart.

The predictor of infection is the intensity of virus flux times the duration of contact,so your hairdresser being around a person for 20 minutes and separated by 20 cm is more dangerous than a meet and greeter with 1000 people at 10 seconds at 2 metres , and maybe 100 infected.
For my part, should I need to spend time indoors in confined spaces with strangers or on public transport, I will want a mask.
 

oldgroaner

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They also lend some credence to the "I had the worst cough/flu I've ever had. Could it have been covid-19?" posts - which seemed to date from early January onwards - getting the answer "Yes!"

Although they are saying we have reliable antibody tests, I am not aware of significant deployment. Yes, there has been muttering about randomised testing.
It seems academic to be discussing "antibody" tests when the government struggles to test "anybody" very often
 
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flecc

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I don't get that.

Most similar devices do NOT have an inside microphone. They use their outside microphone(s) to sense environmental noise, and add generated anti-noise to the signal supplied to the sound element.
True for the external NR headphones like mine, but with these in ear buds they appear to use what external noise leaks into the ear. I'm surprised they work as well as is reported.
.
 

Woosh

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Where are those figures, i use the worldmeter website and it has not given todays data yet.
ONS this morning.
Week ending 24-April, over 40,000 excess deaths since beginning of March, over 30,000 where COVID was on the death certificates.
Deaths in hospitals are coming down, deaths in care homes still rising.
We are only beaten by Donald Trump's USA.
 

oyster

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I think he is slightly over egging the pudding. My calculation suggest on the simple inverse cube that doubling the distance makes at least an 8 fold reduction...and I gave you all the benefit of my calculations. If the spray is gravity driven,then it becomes even more distance friendly..and multiply by.An inverse exponential reduction .. exp(-x/z).. with Z the horizontal distance a spray travels from nose to ground, X the distance apart.

The predictor of infection is the intensity of virus flux times the duration of contact,so your hairdresser being around a person for 20 minutes and separated by 20 cm is more dangerous than a meet and greeter with 1000 people at 10 seconds at 2 metres , and maybe 100 infected.
For my part, should I need to spend time indoors in confined spaces with strangers or on public transport, I will want a mask.
But if your calculations are wrong... ?

My point being that a meeter/greeter in the worst case, belching out vast quantities of viral matter, could infect a LOT of people. A hairdresser working on his/her own with a single client at a time, could at worst manage a few a day. It is also far easier for a hairdresser to wash their hands, etc.
 

Wicky

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It is highly intriguing, and if anything adds credence to a non Wuhan origin. If he presented in hospital on 27th. , He probably contracted it on 15th..of even earlier, since you don't go to hospital with the first sniffle,and certainly not around Christmas.
These dates are important
Not really as there's a possible connection back to China where cases were reported going back to 17 Nov


The man’s wife worked alongside a sushi stand, close to colleagues of Chinese origin, Cohen said. It was not clear whether those colleagues had travelled to China, and the local health authority should investigate, he added.
 

flecc

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Most similar devices do NOT have an inside microphone. They use their outside microphone(s) to sense environmental noise, and add generated anti-noise to the signal supplied to the sound element.
Like you I was puzzled when I first heard of this but could think of nothing other than picking up the external sound inside the outer ear for compactness. I was never going to buy so didn't spend time on it.

I've now been giving it more thought and another possibility occurs. We also pick up low frequency sound through our bodies and particularly via bones, and low frequency is where noise reduction is at it's weakest.

If these buds have an external mike in the extension, it could be supplemented by low frequency addition from the internal mike to give a more effective outcome. That would certainly agree with the reports on how good they are.

If course that attributes an extraordinary level of sophistication in such tiny devices, but perhaps their designers are even more clever than I thought.
.
 

Wicky

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Unfortunately, this is why Coronavirus affects the “disadvantaged” more severely.

Neighbours break lockdown for a game of bingo and a BBQ, two arrested
https://mol.im/a/8286575

You wouldn’t find a neighbourhood of neurosurgeons BBQ ing and having a game of bingo in the street. They would be at home, finding things to do and keeping their children under control.
In the same vein - Farage with time on his hands wanders off to Dover on a 100 mile 'essential' journey...

 

Wicky

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In the same vein - Farage with time on his hands wanders off to Dover on a 100 mile 'essential' journey...

Hopefully Farage will find the time to investigate Whitley Bay for dodgy exercise activity

 

Danidl

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I don't get that.

Most similar devices do NOT have an inside microphone. They use their outside microphone(s) to sense environmental noise, and add generated anti-noise to the signal supplied to the sound element.

Nothing can detect what I am hearing. I could be 100% deaf, or (as is really the case) have notches in my hearing. No hardware can "know" that.
My understanding is that Oyster has the correct explanation. I have two such devices .. a set I got with a Sony NWA 25 music player with tiny wired earbuds and a very complex 3.5mm jackplug. The additional mics are pointing out and the electronics to do the subtraction are in the music player itself. Brilliant it is / was . The noise reduction was so effective that I was able to stand in the que of a very noisy cafe ( back in the day) with women talking before and aft over me, and still be lost in my Mozart. Unfortunately 5 pin jackplugs are rather delicate... Not yet repaired, as those earbuds lead to impacted earwax.
I now have the well respected Sony 1000M3 overear , Bluetooth jobs . Equally marvellous. I can be driving in my 10 year old diesel with a wonkly noisy gearbox ..one of the gears must have a chipped tooth , and I have the plushness and noise levels of a premium Rolls Royce.
 

RossG

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Wow, can you inflate a hot water bottle like a balloon too? I remember seeing acts on TV in the 1970s where people did things like that.
I never went that far. I did read once(again it was only the once) that it was really dangerous to puff up a hot water bottle because if it all goes wrong the pressurised air in the rubber bottle could blow back into your lungs, then you would end up looking like the bottle instead.
 

Danidl

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Like you I was puzzled when I first heard of this but could think of nothing other than picking up the external sound inside the outer ear for compactness. I was never going to buy so didn't spend time on it.

I've now been giving it more thought and another possibility occurs. We also pick up low frequency sound through our bodies and particularly via bones, and low frequency is where noise reduction is at it's weakest.

If these buds have an external mike in the extension, it could be supplemented by low frequency addition from the internal mike to give a more effective outcome. That would certainly agree with the reports on how good they are.

If course that attributes an extraordinary level of sophistication in such tiny devices, but perhaps their designers are even more clever than I thought.
.
..They are remember that they will typically digitise these microphone inputs compare digitally the actual signal with this noise, digitally subtract making compensation for the travel through these other paths and then drive the headphone coils . The premium models like the 1000m3 will automatically compensate for atmospheric pressure!.
. Actually I saw and listened last year to a set of bone conduction head phones in France. I am big into novelty and quirky science , but their audio performance was not enough to tempt me at 80 euro..very mediocre in fact.
 
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soundwave

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Danidl

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In the same vein - Farage with time on his hands wanders off to Dover on a 100 mile 'essential' journey...

Mr Farage is a private citizen ,holding no public office. He should be issued with a summons . As a message to the wider public it would be salutary. He can claim in court his "exemptions"
 
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Danidl

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Not really as there's a possible connection back to China where cases were reported going back to 17 Nov


The man’s wife worked alongside a sushi stand, close to colleagues of Chinese origin, Cohen said. It was not clear whether those colleagues had travelled to China, and the local health authority should investigate, he added.
.. yes I am aware of the November diagnosis in Wuhan. But it does beg the question and requires the evidence to be tested. There is no clear path back to China established as yet.
 

Barry Shittpeas

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Like you I was puzzled when I first heard of this but could think of nothing other than picking up the external sound inside the outer ear for compactness. I was never going to buy so didn't spend time on it.

I've now been giving it more thought and another possibility occurs. We also pick up low frequency sound through our bodies and particularly via bones, and low frequency is where noise reduction is at it's weakest.

If these buds have an external mike in the extension, it could be supplemented by low frequency addition from the internal mike to give a more effective outcome. That would certainly agree with the reports on how good they are.

If course that attributes an extraordinary level of sophistication in such tiny devices, but perhaps their designers are even more clever than I thought.
.
The AirPod pros are extraordinarily good, but at £250 per set they need to be. Very practical too, they charge in the storage case which has a battery in it. I’ve not had to charge the case yet and have charged the AirPods quite a few times.

I’m sure the internal mike is for the ANR and for the “leakage test”. As I mentioned earlier, my old flying hat had the microphones in the ear cups.
 
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