Gas station without pumps

2022 January 27

PVC again

Filed under: Circuits course — gasstationwithoutpumps @ 17:34
Tags: , ,

In PVC: Premature Ventricular Contraction and PVC and pulse, I posted some ECG recordings of my heart to show the premature ventricular contractions.

I recorded for about 209 seconds, and I got 119 spikes and 56 PVCs.  The overall pulse rate was 50.0bpm, but the sinus rhythm was only about 33.9bpm with 15.8 PVCs/min.  That is a very high rate of PVCs.

Here are the averaged waveforms for Nov 25 again (about 209 seconds with 119 normal spikes and 56 PVCs).  The overall pulse rate was 50.0bpm, but the sinus rhythm was only about 33.9bpm with 15.8 PVCs/min. The PVC burden was 32%, which is very high (anything over 10% is considered frequent).


The solid lines are the ECG signals (in mV) and the dashed lines are the optical pulse signal (in dB, because I was using a log-transimpedance amplifier).

I have still do not have a setup that lets me record my heart beat while exercising—the ECG gets too many movement artifacts (enough to cause clipping), and my hand is not steady enough for the optical pulse monitor to work.  I plan to build a new ECG amplifier with lower gain (particularly in the first stage), so that I won’t get clipping. I still haven’t figured out how to get the pulse monitor to work—I probably need a gentle clamp, like a pulse oximeter uses, but I’ve not figured out how to make one yet—I’ll probably need to 3D print something, but coming up with the right strength of spring to get appropriate pressure is the hard part.

In the meantime, I’ll do resting ECG recordings occasionally, to see if there is any change.  I made some recordings on 26 Jan 2022 while lying down.  Here is the average of Lead I from the longest of them (628 seconds, 48.1bpm, 355 normal spikes and 150 PVCs, 30% PVC burden)—the shorter recordings were completely consistent with this longer one.


The spikes were a little smaller than before, so I had to tweak the program a little to find all of them. The shape of the PVC waveform in the S region is a little different, but overall the results are much the same as in November. My hand was not relaxed and steady enough while lying down, so the optical pulse measurements were not good, and so I did not bother plotting their average here.

I did a little library research on PVCs, because the consumer-level information about them said that they were generally harmless, but frequent ones could increase the risk of cardiomyopathy. The best review I found was Evaluation and Management of Premature Ventricular Complexes by Gregory M. Marcus, Circulation. 2020;141:1404–1418

The article suggests that over 10% of pulses being PVCs is associated with increased risk, but that people in my situation (normal left-ventricular ejection fraction (LVEF), no symptoms, >10% burden) should be given an echocardiogram annually and not otherwise treated until something changes.  I will pass on that citation to my physician before my next annual checkup, unless I find a better one in the meantime. There seems to still be a lack of knowledge about whether PVCs are a serious risk factor or not (or under what conditions they are a risk factor).

Mixer-bowl bread again

Filed under: Uncategorized — gasstationwithoutpumps @ 16:46
Tags: , , , ,

Once again I’m trying a bread baked in the bowl for our KitchenAid mixer, similar to Mixer-bowl bread.

On Wednesday I made a sponge using

1 cup sourdough starter
1 cup all-purpose flour
1 cup warm water

I let it rise for a day, and Thursday morning I took out one cup of the sponge to refrigerate for future sourdough.  I then added

1 Tablespoon salt
1 Tablespoon cocoa powder (Droste)
2 Tablespoons dark brown sugar
2 Tablespoons olive oil
½ cup warm water.

While mixing with the dough hook, I gradually added

3 cups whole-wheat flour

The dough was quite dry this time. I turned the dough out onto a counter floured with whole-wheat flour and kneaded by hand for a couple of minutes, keeping the dough lightly floured though there really was no danger of it sticking.  This used another

⅛ cup whole-wheat flour

and resulted in a fairly stiff dough.  I put it in a mixing bowl (not the one from the mixer) with a little olive oil and turned it to coat the ball of dough with oil.  I’ll let it rise for about 20 hours with a damp cloth covering the bowl.

Friday morning, I’ll grease the bowl of the KitchenAid mixer with

cocoanut oil

and turn the dough into the mixer bowl.

Let it rise in the new bowl for 6 hours. Bake at 400°F for about an hour Unitli the center of the loaf is about 150°F), then remove from bowl and bake on tiles for another 20 minutes (until the center of the loaf is around 193°F).

Here is the finished loaf (much smaller than previous mixer-bowl loaves, probably because of the stiffer dough):


2022 January 25

January tomatoes

Filed under: Uncategorized — gasstationwithoutpumps @ 11:00
Tags: ,

I posted about my tomato plants in November and again in December, surprised about them hanging on so long. The volunteer plant on the patio finally died, but the cherry tomatoes on the driveway are still (barely) alive:


I don’t know whether the small amount of fruit on the plants will ripen before the plant dies.


There are still flowers, so we might get more fruit.

Our “winter” has been very mild so far, with only a few light frosts. If that continues, the plants may survive into the spring. The warm weather also has meant that the lawn has gotten quite long—I had to mow the lawn yesterday. At this time of year the “lawn” is almost all oxalis, which is very wet and clumps up in the mower—I had to keep bumping the mower on the sidewalk to dislodge the buildup.

2022 January 23

Secret Walks: East Harbor–Arana Gulch

Filed under: Uncategorized — gasstationwithoutpumps @ 15:16
Tags: , , , , , ,

On Saturday 22 January 2022, my wife and I did the last of our walks from Secret Walks & Staircases in Santa Cruz, by Debbie Bulger and Richard Stover: the East Harbor–Arana Gulch loop.  We rotated the loop to start and end in Arana Gulch (the closest point for us).  Walking to Arana Gulch, we took Laurel and Broadway to Ocean View then moved over a block to Windsor to Harbor (2.9 miles).  The loop itself was 2.6 miles, and we walked back along Windham to Ocean View, took Soquel to downtown, and took our usual route home up Lincoln (3.2 miles).  So the total walk was 8.7 miles.

This walk was the first one using my new Panasonic Lumix ZS80 ultrazoom camera.  I carried it on a cross-body sling (OP/TECH USA 1601512), and I had the monopod that my son gave me, to steady the camera on telephoto shots. Eventually I put the monopod on the camera even when carrying it, because holding the camera with the stick was steadier than the usual grip.  I only extended the monopod to take telephoto pictures.

I played a lot with taking long telephoto shots, because that was something I could not do with the old camera or the phone. Most of them are not worth showing, but I’ll include a few anyway. The longest distance shot I took was of the Chaminade at 1.6 miles, but I also tried telephoto shots of water birds, sail boats, stand-up paddleboarders, … .  Framing the extreme telephoto shots was often difficult, as even the smallest hand tremor made me lose the subject.  The camera does have a button on the back for temporarily dezooming and rezooming, but using it was a bit tricky, as it required (for me) changing hand positions.

This sea otter painting on electric box (corner of Ocean and Broadway) is one I’ve always liked. My wife and I couldn’t help noticing that the electric box in front of the Art League had not been painted yet—this seems like a missed opportunity for the Art League.

This garden ornament was much easier to photograph with the telephoto lens.

As was this one facing it.

I rather like the unusual slightly domed top to the tower on this house.

In Arana Gulch the cows graze at this time of year, to keep the grass down and allow the endangered Santa Cruz tarplant to grow. The cows have ear tags with their names—these two are Megan and Lili.

I took a picture of the Chaminade resort from Arana Gulch, a distance of about 1.6 miles. Haze and perhaps a little motion blur from the camera limited the quality of the picture.

Here is where we joined the “official” walk. The instructions are a bit unclear about which path to take, but it is the lower, wider one that is relevant.

We saw some miner’s lettuce planted beside the harbor—my wife thinks that it might be a good thing for us to grow.

The colors of the kayaks made for a cheerful image.

This pipe seems to be part of the dredging infrastructure.

Live crabs were for sale directly from boats in several places in the harbor. The crab season is fairly short.

This duck appears to be a female common goldeneye. I had some difficulty keeping the duck in frame at the high zoom I was using—a focal length, equivalent to 944mm for a 35mm camera. There is a little blurring here, but I’m not sure if that is from the autofocus or motion blur.

This grebe was even further away—I used a focal length equivalent to 1319mm on 35mm. Its foot at the back is raised—a maneuver unique to grebes called “foot-shipping”. Supposedly they shake the water off and either leave the foot in the sun or tuck in under their wing to conserve heat.

The ripples and the grebe made a nice abstract image (the 35mm equivalent here was 1720mm).

Another crab sale—this one with a little more visible advertising.

We did not get very close to the Walton lighthouse, but the telephoto lens does a fair job of capturing it.

The sailboat was far enough away, and there was enough haze over the water, that this zoom that combines optical and digital zoom (2010mm equivalent) resulted in a rather impressionistic rendering of the sailboat. The optical zoom runs out at 720mm equivalent.

The standup paddleboard picture was also an attempt to see how much zoom I could use.

The recent Tongan volcano did cause a tsunami to flood the parking lot at the harbor.

Notices for entering and leaving the low-lying region immediately around the harbor are fairly clear.

The harbormaster has a nice lookout over the lower harbor.

These pigeons on the wires were there pretty much the whole time. Here I’ve used moderate zoom (equivalent of 160mm) to frame the picture.

Again, playing with the zoom let me see the birds much closer than my old camera (the equivalent of 1293mm here).

Looking back down the Mello steps gives a fair idea how steep they are.

This is a full wide-angle shot (the equivalent of 24mm) of Arana Creek from the bridge spanning it.

Here I’ve zoomed into just a little part of the previous image (883 mm equivalent, so a little bit of digital zoom past the 720mm optical zoom).

The shadows on the bridge show off the cut-metal panels.

This darkling beetle (family Tenebrionidae) was photographed in Arana Gulch, but I have no idea which of the 20,000 species it is.

On Windham we cam across a new Little Free Library—so new it did not have any books yet. (If we’d known we’d find an empty library, we would have brought some books with us to add.)

I like this photo of a painted electric box because of the juxtaposition of a real palm leaf with the painted palm on the box.

Although we have finished all the walks in the book, we don’t plan to stop walking—we’ll just have to start making up our own routes. If locals have suggestions for us (preferably no more than 9 miles, including walking to and from our house), please let me know.

2022 January 20

Red bean paste buns again

Filed under: Uncategorized — gasstationwithoutpumps @ 20:08
Tags: , , , , ,

For this week’s bread-and-tea I want to make bean-paste bao again.  I already posted the recipe I used for making the koshi-an (sweet red-bean paste) and a recipe for the bao dough, so this post will just have an updated recipe for the dough.

I made the koshi-an tonight, and it looks and tastes like it should, though the azuki beans are probably getting dried out, as it took about 8 hours of simmering to get them soft enough to push through the food mill.  I’m always amazed how the bean paste looks so grey and crumbly after the water is squeezed out, and adding the sugar makes it even paler and drier-looking, but heating and stirring makes it shine with the lovely red-bean-paste color.

For the bao, I am still adapting the recipe from Mai Leung’s Dim Sum and Other Chinese Street Food. I don’t have cake flour or pastry flour in the house, but I do have all-purpose flour. I did once try cutting all-purpose flour with sweet rice flour, but the results were terrible, so this time I’ll just try using straight al-purpose flour.

Furthermore, our household has gone vegan for January (veganuary), so I won’t use lard or butter.  I have a choice of a vegetable shortening made from red palm oil and coconut oil or pure coconut oil. Since I think that the palm oil has worse ecological impact than coconut oil, I’ll try the pure coconut oil this time.  It shouldn’t matter if it imparts a bit of coconut flavor to the dough, since I’m using a sweet filling.

Step 1:

1 tsp yeast
¼ cup lukewarm water
½ cup sifted all-purpose flour

Mix together and proof for fifteen minutes.

Step 2:

2 cups sifted all-purpose flour
½ cup powdered sugar
½ cup warm water

Mix with the sponge from step 1 and let rise for 2 hours (until doubled).

Step 3:

1 cup sifted all-purpose flour
2 teaspoons baking powder
1 tablespoon coconut oil
¼ cup slightly warm water

In a large mixing bowl, mix the flour and baking powder, then knead with the dough from Step 2, gradually adding the coconut oil and water. The dough was very dry, so I added an extra two teaspoons of water.  The dough was still rather dry, but seemed kneadable. 

Roll the dough into a sausage shape about 1½ inches in diameter, cut into 12 equal pieces and roll each one into a ball. Keep covered with a damp towel. Let rise until more than doubled (about 3.5 hours). I did the rising after the rolling into balls, rather than before, this time.

Cut 12 3-inch squares of waxed paper.  Roll each ball into a circle about 2½ inches in diameter, but no thinner than ¼” thick. (Using my cookie sticks!) Pinch the outer edges to be a little thinner. Wet the outermost ½” of edges of the circle with a wet fingertip, to encourage sealing.

Put about 1 tablespoon of filling in the center of the circle, then pull up the edges and pinch and twist them to seal. Put the bun flat-side-down on a waxed paper square. Let the buns rise for 30 minutes before steaming.

Keep the buns at least ½ inch apart in the steamer, and steam for 15 minutes. Serve hot.

Steamed buns can be frozen and thawed, then re-steamed.

21 Jan 2022: Here are the photos of the bao that I promised yesterday—about 5 of the 12 seem to have sealed ok, so I need to either make the dough wetter or do something to improve my technique. (Colored text above are modifications to the post since yesterday.)


The 12 bao in the bamboo steamer.


The five that did not open up too much on a black platter.

Next Page »

%d bloggers like this: