Post #1523: Ending the COVID-19 data week flat, still 33 new cases per 100K

 

A trend is a trend until it ceases to be a trend.   The U.S. remains at 33 new cases per 100K population, essentially unchanged from seven days ago.  This is starting to look like a typical turning point in one of these COVID-19 waves.  Case rates are rising in some areas and falling in others, and the net (average) just happens to work out to be flat.  We have not yet reached the point where new cases are falling uniformly across the U.S., but it looks like we’re headed there.

Continue reading Post #1523: Ending the COVID-19 data week flat, still 33 new cases per 100K

Post #1521: COVID-19 trend to 5/25/2022, and a reason to stay out of the cardio room at the gym.

 

The U.S. is back up to 33 new COVID-19 cases per 100K population per day, up 8% over the past seven days.  It now looks as if the Northeast region — the leader for the Omicron-II wave — has peaked.  That suggests that the U.S. as a whole should not be far behind.  The current, stable rate of new cases in the U.S. is the result of continued increases in most of the country being offset by reductions in the Northeast and Midwest regions.

Data source for this and other graphs of new case counts:  Calculated from The New York Times. (2021). Coronavirus (Covid-19) Data in the United States. Retrieved 5/26/2022, from https://github.com/nytimes/covid-19-data.”  The NY Times U.S. tracking page may be found at https://www.nytimes.com/interactive/2020/us/coronavirus-us-cases.html

Here’s the Northeast by state, where the peak continues to shape up nicely.  As they were the leaders on the up-slope of this wave, they should be the bellwethers for the peak.


Extreme aerosol emissions from intense aerobic exercise

 

 

One of the earliest U.S. COVID-19 super-spreader events occurred at a church choir practice in Washington State.  More than 50 persons (of the roughly 60 in attendance) were infected, and two died.

The terrible thing about this event is that they did everything “right” according to then-current CDC guidance.  But this was still the period during which the CDC was in denial about aerosol (airborne) transmission of COVID-19.   At that time, the CDC was still telling people that COVID spread via large droplets that rapidly fell out of the air.  Accordingly, the official party line was that if people stayed 6′ apart, all would be well and there would be no transmission of COVID-19.  No need for masks, ventilation, or other measures.  If you read the CDC’s official write-up about that event, they are still in denial, and per the existing, absolutely implausible writeup, that an entire roomful of persons was sickened by one index case because they failed to stay 6′ apart.

Putting the CDC’s past intransigence behind us, it’s now well-established that COVID-19 spreads via aerosols (tiny droplets that can float through the air).  We know that certain people (“superemitters”) and certain activities greatly increase emission of those aerosol droplets.  And, in particular, we know that singing produces as much aerosol emissions as coughing.  This is why some countries (e.g., Germany) and many U.S. mainstream churches banned singing in church for the duration of the emergency phase of the pandemic (see e.g. Post #678, or search this site for “singing”).

In hindsight, then, it’s no mystery why this choral practice created a superspreader event, as did many similar situations around the world.  It as if nearly every first-world country had at least one major church-based super-spreader event, e.g. Post #679).

You can extend that to any situation with crowds and loud talking.  Plausibly, this is why going to a bar seems to have been the most dangerous activity possible for spread of COVID-19, and why bars were always the first sites to be shut down when COVID-19 restrictions were in place.  Followed by indoor dining.  As it turns out, sipping a drink and talking loudly is just about the worst thing you can do in terms of aerosol emissions (Post #723).

If talking loudly increases aerosol emissions (Post #585), and singing does the same, it should come as no great shock that breathing heavily likely increases aerosol emissions as well.  This is probably why many lists rated “working out at a gym” as a relatively high-risk activity during the pandemic (Post #811).

Based on reporting in yesterday’s NY Times, research now shows definitively just how much intense aerobic exercise increases aerosol emissions.  This research, published in the Proceedings of the National Academies of Science,found the aerosol emissions increased well over 100-fold at maximal exercise rate, compared to emissions at rest.  My recollection is that this is modestly higher than was found for singing or coughing.  Thus, I believe that working out at your maximum aerobic capacity — breathing as hard as you can breathe — increases your aerosol emissions more than any other activity measured so far.  The upshot is that high-intensity indoor group exercise is likely among the most dangerous activities for spread of COVID-19. 

The research explicitly notes that emissions during intense exercise are far higher than emissions during loud speech.  For a given density (persons per square yard), and given level of ventilation, from the standpoint of COVID-19 transmission, you’re safer in a bar than in an aerobics class.

The article shows that the biggest increase occurs when you push really hard.  Moderate aerobic exercise pushes up aerosols somewhat.  But the big increase occurs when you are pushing yourself as hard as you can.  More-or-less, emissions are a function of how hard you breathe.  And, interestingly, trained athletes — with higher aerobic capacity — are capable of emitting more aerosols.

Source:  Adapted from “Aerosol particle emission increases exponentially above moderate exercise intensity resulting in superemission during maximal exercise”, Benedikt Mutsch, Marie Heiber , Felix Grätz , Rainer Hain et al, PNAS May 23, 2022m https://doi.org/10.1073/pnas.2202521119

There’s a clear policy implication here for Virginia and likely many other states.  When mask mandates were imposed for indoor public spaces, Virginia made an exception for individuals using cardio equipment in a gym.  In the gym my wife and I (used to, and maybe will again) use, you had to wear a mask walking around, using the weights, and so on.  But you did not have to wear one while using the cardiovascular equipment or otherwise engaging in intense aerobic exercise.  (Though, to be clear, I continued to wear one in that situation for my own protection, because breathing deeply is also the best way to inhale aerosolized virus directly to the locations where it can take hold most effectively.)

Based on this research, that’s entirely backwards.  It’s the people using the cardio equipment that pose the greatest threat to others, and for whom mandatory masking would generate the greatest public health benefit per person.

Given that we’ve all put this behind us, I don’t expect to see any changes in policy.  But if — as many expect — we have a winter COVID-19 wave, this research provides a reason for the cautious among you to skip the indoor aerobics when case counts are up.  A room full of people breathing heavily from intense cardio exercise is probably not a room you want to be in during an airborne pandemic.

Post G22-019: Parthenocarpic Catch-22.

 

The question.

Recall Post G22-013, where I proposed to bypass last year’s troubles with cucumber beetles and squash vine borer by growing parthenocarpic varieties of both plants.  A parthenocarpic plant is one that produces fruit without fertilization, that is, without pollination.   No bees needed, which means I can grow them inside an insect-proof enclosure, excluding the bees along with the pests.

The resulting fruits are sterile and lack fully-developed seeds.

I have to admit, as I ordered up a few packs of seeds for various parthenocarpic cucumbers and squash, I did have this nagging little question:  How do they produce viable seeds from parthenocarpic plants?  Isn’t “seedless cucumber seeds” an oxymoron?

I stifled that question and ordered the seeds anyway.  The seeds I bought were offered by a presumably reputable seed merchant.  And I know that greenhouse-based farms produce plenty of produce from parthenocarpic varieties.  Didn’t seem like much of a risk.

That said, buying seeds for seedless cucumbers does seem like a bit of a Catch-22.  Or maybe a chicken and egg problem.  Perhaps my local nursery stocks the seedless cucumber seeds right next to the dehydrated water.

At the time of purchase, I noted a seemingly unusual percentage of purchasers’ comments complaining of low or no germination rate.  But you see comments like that on the sites of any seed vendor.  I chalked up the squawking to the relatively high cost per seed.  These parthenocarpic varieties seem to sell for anywhere between 25 cents and 50 cents per seed A poor germination rate is not much different from mulching your plants with ground-up dollar bills.

And now, of the 20 seeds planted (five different varieties, three cucumber, two squash), in peat pellets, exactly four seeds appear to have sprouted.  These are from two cucumber varieties.  All the rest of my new whiz-bang parthenocarpic seeds appear to be duds.

But is that normal?  And is it true that they failed to sprout, or is there some other explanation?  Because if that’s really the germination rate, I paid somewhere around $1.75 per viable seed.    For cucumbers and squash.  Which feels more akin to mulching your plants with $20 bills.

So that gets back to the main question of this post:  How, exactly, do seed vendors produce seeds for parthenocarpic varieties?  (Or, more simply, where do seedless cucumber seeds come from?) And is there usually a low germination rate for parthenocarpic varieties?


The answers.

As it turns out, there are several ways in which you can get viable seeds for “seedless” parthenocarpic plants.   But as far as I can tell, the most common parthenocarpic varieties are F1 (first-generation) hybrids.  So, by and large, you don’t get seedless cucumber seeds from seedless cucumbers.  You manufacture them by crossing two seeded varieties that generate the parthenocarpic (seedless) first-generation hybrid offspring.

Of the five varieties I planted, four of the five ( Diva Cucumber, Sweet Success Cucumber, Easy Pick Gold II squash, and Golden Glory squash) are either explicitly marketed as F1 hybrids, or simply as hybrids.

For those, there’s no fundamental reason they would have any lower germination rate than any other F1 hybrid.  These same varieties are planted by commercial farmers growing produce in greenhouses and poly tunnels.  Presumably, they wouldn’t put up with extremely low germination rates.

The sole exception to the F1 rule is Little Leaf cucumber.  As it turns out, that is an open-pollinated variety, not a hybrid.  But that’s also a gynoecious variety — that is, it produces all (or nearly all) female flowers.  Thus, you can get a Little Leaf cucumber with seeds, in the rare event that a male flower is produced that fertilizes one of the many female flowers.

So the upshot is that of the five seedless varieties I’ve chosen, four are F1 (first-generation) hybrids, so the seeds for them are actually produced by crossing two non-parthenocarpic varieties.   I don’t think they’ll produce seeds under any circumstances.  And the last one is seedless, but only because the plants are rarely fertilized owing to its gynoecious nature.  It’ll produce either seeded or seedless cucumbers, depending.

Now that I know how this works, I’ve done what I should have done from the start, and dissected the peat pellets that I planted these in.  Mystery solved: There are no seeds inside.  Plausibly, some birds came by and pecked the seeds out while I had these sitting outside.  So all I need to do is replant, and be a bit more careful, and I should be able to proceed according to plan.

I’ll report back on the actual (bird-free) germination rate in a couple of weeks.

Post #1519: Inflation and Occam’s Razor

 

The American penchant for ignoring the rest of the world never ceases to amaze me.  And so, after reading my N-hundreth story about U.S. inflation rate — with nary a whisper about the rest of the world — I felt motivated to blog about the elephant in this particular room.

Much of the reporting on U.S. inflation is fundamentally idiotic.  It’s noise generated for political advantage, with no content.  It’s all about exploiting an opportunity for finger-pointing.  It lacks substance because all of that reporting assumes there’s some unique U.S. cause to our unique U.S. inflation.

I was going to invest maybe a whole ten minutes in looking up the current inflation rate in selected countries.  But this is the age of the internet.  Maybe somebody put all that information in one convenient place.

So that, if for some peculiar reason, you, as an American, actually wanted to know what the inflation rate was in countries other than the U.S.A., you wouldn’t even have to search for it.  Just look it up on the Financial Times website.

This takes the drama out of doing this one country at a time, but it gets right down to the bottom line.  Here are graphs of the inflation rate in the U.S., North America, Europe, Asia (other than China), and the world as a whole.  (I exclude China because they don’t have a credible domestic inflation measure.)  These are all taken from the Financial Times website.

Notice anything?

Now it’s time for Occam’s Razor.  On the one hand, maybe each of these countries has some unique, specific factors boosting their individual rates of inflation.  Simultaneously.

Or, just maybe, something has happened world-wide, to cause prices to rise.  But it’s so tough to imagine what could possibly account for an increase in inflation in almost the entire industrialized world.  It’s not as if these countries had anything in common over the past couple of years.

In any event, this is why I’ve had my fill of U.S. reporting on inflation.  It’s just so damned dumb.  The endless blather about why it’s due to this, that, or the other uniquely American factor.  The constant drumbeat of whom to blame for it.  But mostly, the absolute unwillingness to take five minutes, look around, and note that this is  not an American issue, it’s a global phenomenon.

 

Post G22-018, Sprawl method for tomatoes.

 

End-of-season edit:  When all is said and done, I won’t be doing the sprawl method again with full-sized tomatoes.  Maybe I planted these too closely, but I ended up with a tangled mass of vines, weighted down by the fruit.  A lot of tomatoes ended up rotting.  Either you can’t see them, or you can’t get to them, or they end up on the ground.  It’s a lot less effort to grow them, compared to staking them up, but you don’t get much in the end. 

Everything else here:  Cold-tolerant tomatoes, and electric fence as deer deterrent, gets two thumbs up.  I now plan on growing cold-tolerant (short-season) tomatoes every year.

I’m now in Phase III of my four-part tomato strategy for 2022.  I outlined that in  my first garden post of 2022 (G22-001).  It’s time for an update.  I’m posting it because otherwise I’ll never be able to recall how things went this season. Continue reading Post G22-018, Sprawl method for tomatoes.

Post #1516, COVID-19 trend, now 31/100K/day, rising 23%/week

 

At this point, I could probably just copy a post from any random day in the past month or so, and I doubt anyone would notice.  New cases continue to grow roughly 25 percent per week.  Today’s case count of 31/100K/day is there just a matter of arithmetic, plus or minus some random variation. Continue reading Post #1516, COVID-19 trend, now 31/100K/day, rising 23%/week