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Masks
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PLee
Joined: 08 Dec 2003
Posts: 3688
Location: Brooklyn, NY

4/23/20 3:38 PM

There are apps for the iPhone that will measure your pulse and your oxygen levels by using the iPhone camera on your fingertip. I've read that the oxygen level reading is within 2% - accurate enough.

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Jesus Saves
Joined: 16 Jun 2005
Posts: 1150
Location: South of Heaven

4/23/20 4:34 PM

Tightness in the chest is preceded by a fever for a viral infection.

Besides a pulse oximeter, I would recommend a spirometer. Their utility extends well for runners and cyclists.

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/23/20 5:14 PM

iPhone Apps

An article in the American Journal of Emergency Medicine, July 2019, entitled "The utility of iPhone oximetry apps: A comparison with standard pulse oximetry measurement in the emergency department," concluded:

"While iOx has modest concordance with control, Ox and POx showed almost none. The iOx device was best in correctly identifying hypoxia patients, but almost 1/4 of patients were incorrectly classified. The three apps provided inaccurate SpO2 measurements and had limited to no ability to accurately detect hypoxia. These apps should not be relied upon to provide accurate SpO2 measurements in emergent, even austere conditions."

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PLee
Joined: 08 Dec 2003
Posts: 3688
Location: Brooklyn, NY

4/23/20 9:16 PM

Did they say anything about the pulse oximeters that were built in to the Samsung Galaxies pre-Galaxy 10?

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/24/20 6:32 AM

I don't know about other smart phones, as I could only access the abstract without paying to read the entire article. But note that the tests involved an iPhone 5s.

Here is the link to the abstract: https://www.ajemjournal.com/article/S0735-6757(19)30467-X/fulltext

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PLee
Joined: 08 Dec 2003
Posts: 3688
Location: Brooklyn, NY

4/26/20 7:03 PM

It appears that the device built into Samsung Galaxy devices (discontinued as of Galaxy 10) uses the same technology as the standalone pulse oximeters in the market. It should be as accurate.

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/27/20 7:24 AM

Grim Reading

My partner is an environmental lawyer, and this document, from an aerosol scientist on one of their expert panels, has been circulating around her orbit:

https://docs.google.com/document/d/11aYBWBP-Scf9FWMFyeh1OxrksqJw9p55MDKtg570K28/edit

If it doesn't open, I'll copy and paste--important information, I think.

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Steve B.
Joined: 19 Jan 2004
Posts: 759
Location: Long Island, NY

4/27/20 1:34 PM

This is really good advice, thx for posting

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dan emery
Joined: 11 Jan 2004
Posts: 6545
Location: Maine

4/27/20 2:16 PM

Good advice

Interesting this includes the 20m following distance for cycling at speed mentioned in the Belgium/Netherlands analysis mentioned earlier.

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Sparky
Joined: 08 Dec 2003
Posts: 18172
Location: PDX

4/27/20 3:29 PM

I don't ride near walkers, runners, etc. 15' around and turn away as I pass.

Cycling not an issue, I am in the boonies/hills and never see anyone, even cars are near non-existant.

Best part of that is no one sees my pitiful going up antics. Not alway too pretty....

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/27/20 4:26 PM

20'

I think the link actually takes you to the Belgium/Netherlands study.

Oddly enough, when I click on the green highlighted link, I get a "possibly unsafe" message.

I thought the comment about medical doctors not understanding aerosol science interesting, something I would not have realized independently. In any event, science + medicine = ok. Science + medicine + politics = no, not a good mix.

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Jesus Saves
Joined: 16 Jun 2005
Posts: 1150
Location: South of Heaven

4/27/20 4:45 PM

This other link admits that airborne transmission is controversial and shapes the conversation towards indoor droplet transmittal. Indoor only. The original study posted here focused on distance, but not duration.

Let me put this into practical perspective, using a basic probability model.

P(yi) = probability of you being infected while running or cycling outdoors.
P(ii) = probability of encountering an infected individual that is also exercising - as in not feverish, asymptomatic and infectious
P(t) = probability of infected individual transmitting infectious droplets at a given point of time, e.g. cough, heavy breathing, etc.
P(e) = probability of you passing by another exercising individual that if potentiallly infectious.

P(yi) = P(ii) * P(t) * P(e)

Whatever values you assign to the individual probabilities, when you do the math, you come up with a very small value. Very small. For instance, assign a value of 1 as in 100% to P(ii), the the remaining product will still yield a very small value. That is true even if you assume mutually independent events. You are probably more likely to be fatally hit by a car out cycling.

That is the problem with the original study posted here. It's analysis was excellent, truly so, but starting with information (other people's research) that is truly suspect. Weak, extrapolated input. I mean suspect in that there is not enough sufficient information known yet about the virus infection to derive really accurate models.

Even assuming one event to be accurate or even generously optimisitc, there are still other related (conditional) probabilisitc events to consider, ones that you can, with reason expect to be very small. Those details need to be considered, too.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 4797
Location: Nashua, NH

4/28/20 6:14 AM

That last article seems way too over-the-top and paranoid to me. There's a fine line between prudent and ridiculous. We're avoiding people as much as possible when outdoors, keeping our distance, reducing shopping trips as much as possible using hand sanitizer, etc. We're wearing masks when indoors in public places (grocery store, PO, etc.) but there's no f-ing way I'm going to wear one while riding. If I lived in a city, it would be different, but that's never going to happen.

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/28/20 10:06 AM

Neither ridiculous nor paranoid, but a different balance of science and politics.

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Sparky
Joined: 08 Dec 2003
Posts: 18172
Location: PDX

4/28/20 11:47 AM

Seemed like a good smattering of 'over compensation as to lessen liability' to me.

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KerryIrons
Joined: 12 Jan 2004
Posts: 3118
Location: Midland, MI

4/28/20 2:17 PM

Framing

As is always the case, hyperbole gets more clicks. This is why historically we have seen so many press releases from academics (and others) that turn out to be nothing in the long term. I know I have mentioned it before, but my favorite was a press release from USC that the male offspring of men who ate more than three hot dogs a week were more likely to get (???? I don't even remember). It was nonsense from the get go, but "it made the papers."

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dan emery
Joined: 11 Jan 2004
Posts: 6545
Location: Maine

4/29/20 3:14 PM

Paranoia strikes deep

Back to oximetry. I ordered one, then read an article saying they weren’t really that useful for for layfolks, and I probably wouldn’t have ordered one if I’d read that first. I’m riding quite well so I wouldn’t suspect I was short on O2, but I also tend to think the more data the better.

So it came today and I’m like Parkin, OK. Next question is whether to get an antibody test. I can get what is apparently a good one near here with a Dr. order, which I can probably get. I think it is possible I have had the virus, as I had what I thought was a bad cold after returning from South America. It may have been that, but now the info is that symptoms are more variable which increases my suspicion. But OTOH, if I have the antibodies, that is not going to change my activities at all because no assurance that provides protection. So my current thinking is don’t bother.

Strange times we are in.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 4797
Location: Nashua, NH

4/29/20 5:42 PM

I just saw a story on PBS tonight that two labs in CA tested 15 of the antibody tests and none of them were accurate enough to be meaningful. It sounds like it's going to take some time for accurate tests to become widely available. I agree with your assessment. If the accuracy is questionable and it won't change anything anyway, what's the point?

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Sparky
Joined: 08 Dec 2003
Posts: 18172
Location: PDX

4/29/20 8:10 PM

"If the accuracy is questionable and it won't change anything anyway, what's the point?"

Unless one considers baby steps changing anything I suppose...

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lrzipris
Joined: 04 Mar 2004
Posts: 528
Location: Doylestown, PA

4/30/20 5:52 AM

The point may be how much caution we each exercise in the face of great uncertainty and risk. To some extent, this is something for each individual to determine for himself or herself in the circumstances each faces: do I do X or not? Do I do Y or not? How much am I prepared to give up or adapt to? Do I live in a rural area, or in a major, crowded city?

This virus seems to be something new, something neither scientists nor doctors fully understand yet, and they are groping towards knowledge, solutions, vaccines, cures.

Scientists may not know the medicine, doctors may not know the science, politicians probably do not know either.

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dan emery
Joined: 11 Jan 2004
Posts: 6545
Location: Maine

4/30/20 9:34 AM

@Brian

Brian, you said you’d never ride with a mask, but what if it was a stylish Rene Herse mask? 😀

https://www.renehersecycles.com/blog/?utm_source=Retail+Customer+Newsletter&utm_campaign=2919ad26be-EMAIL_CAMPAIGN_2017_11_29_COPY_01&utm_medium=email&utm_term=0_f74fbd5ca8-2919ad26be-108703741&mc_cid=2919ad26be&mc_eid=1124689c2b

No, they’re not suggesting you ride with them, but maybe it’s an excuse to buy something else and add the mask....

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 4797
Location: Nashua, NH

4/30/20 6:34 PM

Too late

I've already made some similar masks, using a Singer machine that was made in 1941. I find sewing machines almost as mechanically fascinating as bikes, though I don't use them nearly as often, nor do I have as many (N+1 doesn't apply).

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Sparky
Joined: 08 Dec 2003
Posts: 18172
Location: PDX

4/30/20 7:27 PM

I was cutting, and Elaine was sewing. We made several dozen to donate to the local health dept. They were calling for them, and got them in spades.

Her sewing machine is a bit newer than the 40s. ;)

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dfcas
Joined: 11 Jan 2004
Posts: 2737
Location: hillbilly heaven

5/1/20 4:18 PM

I'm struggling with whether to resume my piano service business. Starting Monday, I'm allowed to resume working. West Virginia has done relatively well thru the virus, as the Gov issued a stay home order early, and we may be the best of all states.

As much as I like working, my head says stay home. So at this time I'm not going back to work or playing in a classic rock band.

I'm 67 with diabetes, and Nancy(SO) has bronchitis/asthma and other issues, so we are high risk.

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dan emery
Joined: 11 Jan 2004
Posts: 6545
Location: Maine

5/2/20 5:30 AM

Good luck Dan

Work presents issues not easy to resolve. Maybe harder if you like to work, like you a and me. Sounds like you’re making the best decision you can. I’m working, though at a reduced level and I have a bunch of unclear choices how to go about it. By coincidence yesterday I got a letter from the feds telling me to apply for Social Security, so I did. Maybe they’re trying to tell me something lol. Though I’m old enough there’s nothing to gain by waiting, working or not.

Bummer about the band, too.

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