How do you Eat a Salad?

I like salads. I do not like trying to eat them neatly. Especially in a restaurant.

One of my favorite salads, with leaf lettuce, mangoes, sugared pecans and raspberry dressing.

Salads do not hold together, and holding together helps if you are trying to get a fork under something. Forks do a poor job of sticking in lettuce if you stab at it. The pieces of lettuce are frequently too wide for one bite, though generally far less than a satisfying mouthful. If the salad has small items, like the mangoes and sugared pecans in the mango salad pictured, they roll off a fork. In short, the conventional fork and spoon just do not work very well for eating a salad. (I except things like coleslaw or carrot salad, where the pieces are very small and glued together with dressing.)

At the same time, the dressing makes a salad far too messy to just pick up and eat.

Perhaps we need to invent something that would do a better job of conveying a bite of salad from plate to mouth?

One could wrap it in a bit of tortilla or pita, I suppose, but that is not always the taste desired. Nor do many restaurants serve them that way.

Is it too much to hope for that someone would invent a new eating utensil suitable for salads? Perhaps some kind of eating tongs? Something small enough to take a bite from neatly? Ideas, anybody?

Breakup Season

The usual four seasons, especially as defined by the equinoxes and solstices, don’t work very well for interior Alaska. Show cover is generally established by a month after the autumnal equinox, and stays on the ground until well after the vernal equinox. Rivers freeze a little later and remain frozen longer in the spring, and the only running water for six months of the year is in hot springs and indoors. But there is one season that everyone both longs for and dreads: Breakup.

Breakup is the time of year when snow melts and rivers thaw. The two are connected by more than sunshine and warmer weather. Melting snow makes mud (one of the reasons breakup is a time of some dread) but it also runs into rivers. If the water rises in the upper stretches of a river before lower reaches are thawed, as often happens in Alaska, the result can be ice jams and resultant flooding. I’ll talk about that some other time, but right now I want to discuss the simple process of melting snow.

Clean snow reflects most of the solar energy that strikes it. Some of the sun’s rays are absorbed within the snow pack, and cause internal melting and settling — but this is a slow process. Even clean snow, however, is a very good absorber in thermal infrared wavelengths. The sun doesn’t put out much energy in these wavelengths, but buildings, trees, and just about everything else except polished metal does. As a result, snow near the south side of a building melts much faster than snow out in the open. So does snow near tree trunks.

I see this every year. In addition to the photo of my road, which is rapidly turning into mud, I took two of the north and south yards of my house, minutes apart. Both areas got almost exactly the same amount of snow, and both have very similar exposure to sunlight. The snow stake still has a good 18” of snow. The ground around the birch is almost bare.

Why? Two reasons, actually, and the combination explains why open birch forest is usually the first natural area free of snow around here. First, birch trees hold their seeds through winter, and drop them shortly before breakup. As a result the seeds on the snow around the tree absorb the solar radiation and transfer that energy to the snow, speeding its melt. Natural selection? Quite possibly. It certainly seems likely that the enhanced snow melt, leading to earlier warming of the ground, would help the tree.

Second, the tree itself absorbs some solar energy, and then re-radiates it to the snow in the form of thermal infrared. Just about any object poking through the snow this time of year has a little depression around it. Spruce trees do an even better job of absorbing sunlight than do birches, but they also shade the ground and transfer much of the energy they absorb directly to the air. As a result spruce forest, while it probably does a better job of warming the air than birch forest, is among the last areas to have completely bare ground.

On a different note entirely, one of the fixtures of breakup in Fairbanks is the Beat Beethoven 5 km race, a fundraiser held today for and by the Fairbanks Symphony Orchestra. I won’t be running this year, though I did “run” with a cane once — and came in last. The idea is to cover the 5 km before the end of Beethoven’s 5th Symphony, about 30 minutes. I’m volunteering this year to park my car along the race route with the radio tuned to 91.5 (KSUA, the campus radio station) blaring out Beethoven’s 5th. I expect temperatures below 50°F and much of the course to be slippery or wet!

Added later (after the race.) This is definitely a family race. There were parents pushing their children in strollers, parents with children in backpacks or riding piggyback, dogs, and one contestant on crutches. (And she wasn’t at the end, either.) I did have a bit of a problem in that instruction to volunteers said if possible, not to have your car idling as the runner went by. I did. And needed a jump to start the car after the battery totally discharged itself.

Guest Blog #IAN

A very quick note. I have a guest blog up on But What Are They Eating about some of the foods my characters eat–and why those using esper talents must eat so much to avoid low blood sugar.

Cold-packed Snow: White Ice

This pile of white ice chunks was scraped off the OLLI parking lot. As you can see, the lot is still white.

I’ve talked about snow that is undisturbed without a temperature gradient, and about disturbed snow without pressure. Today we’re going to take that a step farther and look at snow that is disturbed by pressure—specifically, by car or foot traffic—when temperatures are below freezing. Here in Alaska we call it white ice, and the less-traveled roads and almost all the parking lots are solid white ice this time of year.

Wind or an avalanche will break snow crystals, but it doesn’t in itself press the broken grains together. Walking or driving over dry snow, however, not only breaks the crystals, it also presses them together. If it is near freezing, the pressure may even cause slight melting. In any event the crystals are very firmly welded together. The result is a mass that has some air trapped—that’s why it looks white. But it may be only a little less dense than ice, and is only slightly softer. An icebreaker or a sharp-edged shovel will generally break it much more easily than it will break true ice, but white ice is definitely solid.

Some of the chunks of white ice removed from the road I live on.

As a driving surface, white ice is something most Alaskan drivers learn to deal with. It is not impossibly slippery if it is not polished or near freezing temperature, though most of us drive on it with caution and learn to feather our brakes. Mine are anti-skid, but I’ve learned to brake softly enough that the anti-lock feature almost never engages—except at intersections.  Those are often polished to the point that they are extremely slick, even though graveled.

Yes, graveled. We don’t use salt much because our temperatures are generally so low that even salt water freezes and salt simply will not melt ice. Salt’s used on sidewalks sometimes, but in cold weather each salt pellet simply melts its way down to the pavement without having much effect on the main ice mass—except to make it slicker.

Notice the step left when one lane of my road was plowed a couple of days ago.

The road I live on is gravel, and a coating of white ice actually improves it. But it does do some things you might not think about to paved roads.

First, it covers any marking painted on the road or parking lot—lane markings, turn arrows, lines that mark parking spaces.

Second, it can at times be thick enough that when part of a road is cleared in the spring, a considerable drop-off may result.

Third, and especially a problem when it is overcast and the light is flat, is whiteout conditions. It’s not as bad as in an airplane north of tree line when the pilot may not even be able to see which way is up, but telling what is road and what is not can be very difficult when the road is white ice and the verge is snow and both are exactly the same color. It’s hard to see even with directional light and shadows, but in flat light everything looks the same.

I managed to high-center my car a few weeks ago taking an exit between a four-lane highway and a major side road. The exit was pure white ice, and I couldn’t quite see what was road and what was the curbed triangle between the side road and the exit. I wound up on the triangle and had to be pulled off by a tow truck. Neither the trooper who stopped to see if I needed help nor the tow truck driver seemed to have the slightest problem understanding how I’d gotten there, or even consider my situation unusual. “Whiteout”  was all the explanation I needed.

Inversions and Smokestacks

Why do plumes flatten?

Sometime the plumes from smokestacks just keep gong up until they disappear, but at other times they will stop and start spreading out once they have reached a specific height. Why?

One common explanation is that the plumes have reached a capping inversion and can’t go any higher. There is some truth in this, but it is a major oversimplification. Inversions aren’t something you reach, for one thing. Here in Fairbanks, and throughout the country at night, inversions often start at the ground. Further, they may extend for a considerable distance – up to a mile or more – vertically.

So just what is an inversion?

Under normal circumstances the air gets colder with height. One reason is that air cools as it rises. This is due to conservation of energy: the air is essentially swapping heat for potential energy. For dry air, the cooling rate is about 1°C per hundred meters, or 5.4°F per thousand feet. This is called the adiabatic lapse rate. When water is condensing, such as in a cloud, the air doesn’t cool quite as fast as it rises, because the condensing water adds heat to the air.

In an inversion layer, the air gets warmer with height. The rise can be only a degree or two occurring over a height of a few tens of feet, or it can be up to 20°C or more extending for a kilometer or two. But it is a layer of finite thickness, not just a flat plane at a specific height.

Here in Fairbanks, power plant plumes are generally visible because they contain water, which at low temperatures condenses. As a result it is very obvious when they reach a particular height and suddenly flatten out. But why?

They rise to start with because they are warmer than the surrounding air. They stop rising at the height where their temperature is the same as that of the air around them.

Part of this is because they cool as they rise. But if this were all that were involved, they would rise quite a long way. Suppose the plume temperature when it left the stack were 100°C – the boiling point of water. If it were simply cooling off at the adiabatic rate, it would take 10 kilometers just to reach the freezing point – and I guarantee that the air at 10 kilometers over Fairbanks in the winter never gets that warm.

So why do they flatten out and stop rising?

Because all the time they are rising, they are mixing with the surrounding air. This is actually visible in the photograph – the plume gets wider with height, due to the mixing in of cold environmental air. This works even for very small plumes. I have seen diesel trucks with stacks trailing a plume that flattens only a foot or two above the top of the stack, or stationary sources whose plumes flatten several hundred meters up. It’s a question of how fast the environmental air mixes with the plume as well as the initial plume temperature.

So if you see a plume flatten out, you can be pretty sure it is in an inversion, but not that there is a particular inversion at that particular height.

Technology Index

The Perversity of Inanimate Objects 1 4/10/10
Insulin Pumps 5/20/10
Wars With Word 5/28/10
The Perversity of Inanimate Objects 2 6/4/10
Float Chair (fictional) 6/24/10
Tricycles are not Bicycles 8/8/10
Why Temperature Remembered doesn’t match the Record 4/5/11
Does Banking Software Work? 4/21/11
My New Toy – an iPad 2 5/12/11
Before Computers 6/5/11
How do you Eat a Salad? 4/28/12
Battery Woes 5/12/12
Printer Woes 6/14/12
Adult Proof 9/8/12
Digital Cameras 9/29/12
Who Needs a Nightcap? 9/3/13

Indexing Blog Posts

500+ posts is too many for me to keep track of, and quite a few are “reference” posts, such as the ones on planet building or horse coat color genetics. So I’m putting in a new feature, an index page that links to posts linking to the posts on a given topic. (Sound confusing? Try doing it!)

These indexing posts start today (see below) and will appear occasionally until the reference posts are all indexed. After that I’ll just be updating the index posts, which will be accessible from the Index tab above.

Why an Index?

With 550 posts as of today, I’ve started to have problems remembering what I’ve already put on here. This is particularly a problem with posting existing content such as poems, short pieces from the Summer Arts Festival, or science explanations originally written for the Alaska Science Forum. I can’t remember which books or DVDs I’ve posted reviews on. It also is starting to be a problem when I want to link to a previous post and can’t remember when it was put up or what the title was. And there are posts on this blog that have permanent information, like the series on planet building and the one on horse color genetics, or the book and DVD reviews. I want to make it easier for my readers as well as myself to find things.

I made a start some time ago by adding an index page, which can be accessed from the menu at the top of any page. Right now, the only links are to index pages on my author site. This takes you out of the site and sometimes back in, which is rather clumsy. The index list is also incomplete.

I’m going to start posting an occasional entry which is strictly an index of past posts on a particular topic. These posts will be linked from the index page, and will link forward to the individual blog posts. As it takes a while to find all the posts that belong together, this will be a slow process—probably extending over the next few months. The first in this series, on DVD reviews, is already queued for January 3. Others will follow, most on Thursdays.

I probably won’t be indexing every post. Some, like those early posts which were simply glossary entries for my books, are on the author site and really belong there. Others, like the regular Monday updates on North Pole weather starting in November 2010, can be found easily enough just by using the calendar on the site. But I hope that by the time I have finished this, older posts of interest will be easier to find.

Contuous Glucose Monitors

Continuous Glucose Monitors (CGMs) are a relatively recent development in diabetes control. They are still controversial with many insurance companies, though prevention of even one high-cost ambulance trip to the emergency room should make them cost-effective. But they do have problems.

There are three devices that I am aware of, worldwide, and others in development. The best, according to users, is the Navigator – but it has been withdrawn from the US market. This leaves the Dexcom and the Medtronic sensors. My own experience has been entirely with the Medtronic sensor, but all three work in basically the same way, on interstitial fluid, and all are subject to the same problems of time lag.

Medtronics transmitter (white) and the visible part of the sensor (clear) with a U.S. quarter for scale. I use IV 3000 to hold everything in place.

The sensors available today consist of some kind of reusable transmitter, a receiver, and a disposable needle which injects a small disposable sensor under the skin. The sensor is then connected to the transmitter, which lies against the skin.

The sensors are expensive. The price today at the Medtronic store is $42 a sensor, with an official life of 3 days. (Most people actually manage to use them longer, and in fact I find they are most accurate on days 3-5, though I rarely get one that lasts more than a week.) The big advantage of the Medtronic system is that the Medtronic insulin pump (the kind I have) acts as the receiver, though separate receivers are available. The official life span on the Dexcom sensor is 7 days, though I understand they are correspondingly more expensive. Comments from users of the Dexcom are solicited!

A continuous sensor is extremely useful in that it allows you to see how your blood glucose varies between finger sticks, and also allows you to see whether it is rising, falling or staying reasonably constant. The Medtronic sensor allows you to choose whether to see a 3-hour, a 6-hour, a 12-hour or a 24-hour graph of your blood sugar, or download values about 5 minutes apart to a computer, and I believe the Dexcom sensor is similar. On the negative side, CGM accuracy is highly variable, and it needs regular calibration with a finger-stick meter. There is a further problem (at least with the Medtronic system) with alarms.

I used to eat protein bars for breakfast. They had a good balance of protein, carbohydrate and fat, they took no weighing, and they were consistent day to day. They also produced a considerable spike in blood sugar in the hour after breakfast, easily identified on the CGM graph but missed in finger-stick testing. When I switched to Greek yogurt with fruit, also a good balance of protein and carbohydrate but without the fat, my blood sugar graph leveled out. In fact, the CGM has allowed me to identify many regular meals as causing spikes or delayed rises in blood sugar. (The fat in the bars was not the problem; in fact fat delays the absorption of carbohydrates, but much of the carbohydrate in the bars was fast-absorbing sugars.)

I am not alone in finding trends more useful than absolute numbers. A high blood sugar (within reason) is not really a problem if the blood sugar is decreasing, nor is a moderately low reading with an upward trend. On the other had, a high reading going up or a low reading going lower is cause for immediate finger-stick confirmation and treatment if the reading is confirmed. A low reading at night or if I’m planning to drive is always reason for finger-stick confirmation.

What the sensor actually measures is a slight electrical signal, and this must be calibrated with a finger stick measurement to get the actual blood sugar reading. The calibration constant changes over the life of the sensor, and can drop very fast toward the end of sensor life. Consequently the sensor must be calibrated a minimum of twice a day, preferably when your blood sugar is fairly steady, and may give a lot of false low alarms near the end of its life.

Another problem is that the sensor measures the glucose concentration in the interstitial fluid, that is, the fluid between the cells. While this follows blood glucose, there is a significant time lag. My blood sugar can drop very rapidly, especially during exercise, and as a result CGM measurements during exercise can be much higher than my actual blood sugar. This time lag alone makes me very dubious about using this type of sensor for any closed-loop artificial pancreas.

My biggest complaint with the Medtronic system is the alarms. Ideally, to be most useful the CGM system should wake you up if your blood sugar starts to drop. In fact, the alarm is so low in volume and so high in frequency that I almost never hear it unless I am in a very quiet environment and there is only a layer of cloth between my ears and the pump, not a down comforter. This is partly my hearing, as others will sometimes point out to me that I am beeping. Yes, it does start vibrating eventually if I do not respond, but I feel the vibration only if the pump is tight against my skin. I usually feel it driving (well after I start going low) but often not at night.

Is it worth it? Yes, for me. But it definitely needs some improvements.

Fairbanks Weather, 11/7/11

Did you remember to change your clock yesterday? I spent close to an hour yesterday morning trying to remember where all the clocks were. The computer is automatic, but that leaves two indoor-outdoor thermometers, my wrist watch, my insulin pump and my glucose monitor in the computer room alone. In the kitchen I have the microwave, the stove clock, a travel alarm visible from the stationary bicycle, another thermometer, and the timer on the plant light. Then the bedroom: a radio alarm and a light-and birdsong-and alarm gadget, plus another thermometer. Finally the plant room, with two more timers. Most have to be set 23 hours forward, as it is impossible to reset them backward. I even found the reference on how to change the time on my GPS, in the process discovering a warning against using it while driving.

On Alaska Standard Time, the sun rose at 8:59 am — an hour earlier than ADT — but it will set at 4:09 pm, far too early. Our day length now is only 7 hours and 17 minutes, and the sun at its highest is less than 9° above the horizon. From my south windows, it barely skims the trees, and driving it seems it is always in my eyes.

The birches and aspens have completed their color changes: green, yellow-green, yellow, gold, brown, bare black branches,  white as the branches were covered with a layer of frost, and black-brown again as the wind rose and blew the frost off. That last will alternate through the winter, with periods when branches are white on top and black on the bottom due to fresh snow in windless conditions. There is snow on the ground, but it is deepening slowly here in the Interior. It was 5″ deep yesterday, but it was still too dark to see when this post went live. There is enough packed snow on the roads to make intersections slippery. This time of year I worry about drivers new to the state and those who have forgotten their ice driving skills, or who do not have winter tires.

It isn’t light enough to see the depth of snow yet, but when it became too dark to see last night we had about 5″ on the ground, with more expected overnight.

P.S. As of 8:30 this morning it looks like close to 8″ of snow on the ground. And I’m not looking forward to driving home from my afternoon OLLI class, which lets out just minutes before sunset.

This is post number 488. Remember to comment to take part in the drawing.