An ant under the microscope

I killed two ants the other day, for Science. “Adventures with a Microscope” instructs you in how to kill a fly so that you can remove its legs and eyes for a close look under the microscope. No flies were available, so I victimized some ants who kept trying, with mindless persistence, to invade my personal space. I put them under glass, where one asphyxiated, slowly, as I had no chloroform. The other escaped and I flicked it into some water, where it drowned. I felt more than a few twinges of guilt, staring at their huddled corpses, but then decided to examine them under the microscope.

And oh, how glorious!


40x (lowest magnification):
The segmented, slightly blurry object on the right is its antenna.
The thin filament is (I think) carpet fuzz.

Note the difference in texture between chitin and eye (zoom 100x):

Zoom 200x:


These were all taken with reflected light, since ants don’t transmit light well. But are they not beautiful and alien, seen up so close? We’ve all heard of the fly’s multi-faceted eye. I’m not sure I realized that the ant’s is likewise complex and compound.

Wow.

Chinese Edible Dogs

Yeah, I blinked at the headline, too. One of my projects at the Monrovia Library is scanning old newspapers (on microfilm) into digital files for easy later access (and hopefully indexing). This item came from the July 2, 1915 issue of the Monrovia Messenger:

Interesting slice of history!

Kitty litter considerations

After seven years of scooping kitty litter on a daily basis, one can’t help but meditate occasionally on the environmental impact of the stuff. What kind of litter is best? And what’s the best way to dispose of the scooped-out pet waste, or the used litter?

“Litter and the Environment” (2008) discusses the environmental impact of clay, silica, and plant-based litters. Did you know that the raw clay material (sodium bentonite) is obtained through strip mines, and that “The United States Geological Society estimates that 85 percent of the 2.54 million tons of clay used in this country every year is used for absorption of pet waste, with cat litter being the dominant”? That’s about 2.15 million tons of (ultimately) used-up clay that goes, most likely, into landfills. The article concludes that plant-based litters may cause the least environmental impact, but ultimately there is no perfect solution.

Some alternatives to clay-based litter that caught my eye, and have favorable comments in discussion fora, are:

These are inevitably more expensive than clay-based litters, but might ease your environmental conscience. For the ultimate in cost savings (at the expense of time), you can make your own paper-based litter.

Once you select a litter, there’s still the question of how to dispose of it after it’s used. I scoop waste (pee clumps and feces) from the litter into a Litter Locker, which is super handy (and keeps odors down) but not only consumes plastic, it seals the waste for eternity and guarantees it’ll never break down. But you can’t compost it (temperatures don’t get high enough to break down feces), you shouldn’t flush it (can clog pipes, and there’s a small risk of infecting marine life with toxoplasmosis, although apparently VERY small risk if your cat lives indoors and doesn’t eat mice), and from what I’ve read, most sources regretfully recommend sending it to the landfill. Probably the best solution is to put it in a paper bag or something a little more likely to ultimately decompose (versus plastic), then put it out with your trash.

I change out the unused litter very rarely, like every few months. From browsing online, I learned that some people just let the box fill up with waste and then throw out the whole thing once a week, which must make them go through a ton of litter! Why why why?

Finally, no discussion of this issue would be complete without mentioning the alternative strategy of toilet-training your cat, which uses no litter and takes another chore off your hands. However, the small toxoplasmosis risk would still be present.

I’m considering trying out Feline Pine and/or Yesterday’s News, just to see how well they work (and whether my cat will use them!). And I may try to devise an alternative to the Litter Locker that avoids the use of plastic. Hmm.

Implantable radio science

I had no idea what a broad range of topics the field of “radio science” covers. I recently attended the National Radio Science Meeting in Boulder, CO, to talk with other researchers about the latest advances in radio astronomy data analysis (e.g., hunting for pulsars). Other topics in the multiple parallel sessions included lightning detection, antenna design, remote sensing of rain, “biophotonics”, “metamaterials”, space plasmas, and “telemetry for monitoring and biosensing”. Intrigued by some of the talk titles, I attended one of the latter sessions.

One goal of this field is to develop and test low-power, efficient radio communications for implantable medical devices (IMD). One envisioned application is for people in very rural areas who don’t have regular access to a doctor. Internal sensors could monitor blood pressure and various nutrient levels, then report them to an external base station they could visually check. As one presenter imagined, “Low potassium? Push a button and find out what you should eat for the next week!”

The devices are still under development, and in the initial work they’re focusing on the ability to monitor blood pressure. They aren’t yet up to human trials. Researchers from Texas A&M and Mississippi State University described how they’d started with rats. They showed pictures of the rat surgeries needed to implant the tiny antennas and then described the experiments, which aimed to evaluate whether the simulated response from the antennas was the same as what was observed when it propagated through rat muscle, fat, and skin. Unfortunately, the presenter noted, they’d been forced to euthanize all of the rats after the tests, because they hadn’t coated the antennas with a “biocompatible material” and therefore by animal testing rules they could not let the animals live. (It seems odd to me that this oversight would not have been caught during the protocol review process!) At any rate, the results showed a not very good match between the simulated response and what they actually got, which they attributed to differences between human skin (in the simulation) and rat skin (in reality).

As a side note, I kept wondering if these tests really qualified for the “in vivo” term the presenters applied, since the rats went to sleep for the surgery and (presumably) never woke up. The point at which they were euthanized was never specified. I started wondering whether live fat/muscle/skin tissue has different dielectric properties than dead tissue, which I assume it must, since circulating blood probably affects any signal propagation. This particular experiment seemed perfectly designed to test both cases. But I wasn’t quite up to asking this question after the talk.

The next presenter (from the same group) continued on to describe their subsequent experiments with larger animals (pigs). Pig skin apparently is a much better match to human skin (insert obligatory “white meat” joke here), and they got an excellent match with their simulation. In this case, they used a proper coating and the pigs were permitted to live. The presenter also commented on how very expensive these particular bred-for-experimentation pigs are (about $10,000 each), although I had to wonder whether one must purchase an entire pig to do a radio antenna transmission test, or whether one can give it back afterwards to be used for other experiments, or possibly time-share with other researchers. But again I wasn’t actually able to ask a question, being more sort of transfixed in a rather distasteful fascination and slightly nauseated by all of the graphic surgery images!

These talks didn’t spend much time on other important IMD constraints, like where power for the wireless transmitter comes from and how to dissipate the excess heat generated without cooking the animal (or human) internally. They noted that the devices had a 25 day lifetime if in continuous use, or 1.7 months if only transmitting periodically, so I’m guessing that limit was based on some nonrenewable power source being exhausted.

Overall, the envisioned future of such devices is certainly promising—and I was kind of disappointed to see how premature such investigations apparently are (if this represents the state of the art). I would also have liked to hear more about the kind of technology used for the sensors that collect the data to be sent by the antennas!

The quick brown dogs jump over the lazy hurdles

Today I attended a dog agility competition for the first time, tagging along with my friend Wendy. It was a beautiful sunny day (despite significant fire-induced haze along the mountains) and we drove out to Rancho Cucamonga to Chaffey College for the show. We found a grassy field surrounded by tents and umbrellas to provide shade for the dogs as they waited for their events. We took our seats and watched quietly as a voice said, “Go,” and the first dog and handler pair came out.

There were two courses: “standard” to the left and “jumpers” to the right. Unlike ballroom dance competitions, the dogs seemed to be grouped in descending order of advancement, so first the “excellent”, then the “open”, and then the “novice” dogs competed. The Standard course included a ring to jump through, several low jumps, weave poles, a tunnel, a seesaw, an A-frame (to climb up and then down), a table (on which the dog had to sit for 5 seconds), a dogwalk (raised platform with a ramp at either end), and a chute (like a tunnel but with one end collapsed so the dog has to escape blindly). It was particularly fascinating to watch the dogs traverse the weave poles, which are spaced closely enough that the larger dogs end up hopping with their back legs held together in a complicated slalom to make it through. Very impressive. The Jumpers course was all jumps, plus weave poles and two tunnels, and generally looked easier to my untrained eye, but the dogs seemed to find it more difficult. I also think they had to clear the jumps without touching the bars, while touching I think was permitted in the Standard course (it wasn’t always clear when and for what reason faults were being called). Ultimately I believe these runs were being judged based on time (rather than style, faults excepted), but the times and the final results were never announced, so this is surmise (plus wikipedia research — and of course corrections are welcome!).

It was fascinating to watch the interplay between dog and handler. Some had a degree of synchrony that seemed almost psychic, or as if the dog didn’t even need a handler. Others would be going along fine and then the dog would just break focus (often for no apparent reason), leaving the frustrated and/or embarrassed handler to dance around, calling instructions, until giving up and carrying the dog off the course. Some handlers had a calm clear voice and others shouted continuously, sounding angry (but apparently investing energy in the voice helps communicate a need for speed to the dog). Some dogs would randomly run in the wrong direction or off the course — mistakes that would leave you wincing in sympathy.

Overall, it looks like a great way to spend time with your dog (and get exercise with yourself), and from what I saw, the dogs in general were very well behaved both on and off the course.

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