Gas station without pumps

2016 November 27

Cyber Monday sale 2016

Filed under: Circuits course — gasstationwithoutpumps @ 12:01
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My Black Friday sale was a moderate success (12 copies of my book sold for total royalties of about $25).  The sale continues through Cyber Monday (end date 29 Nov 2016), with the same coupon reducing the price to $2.56:

I’m not going to get rich off of this textbook, but I’m hoping that a few other teachers of electronics will pick it up and use it for a course.

2016 November 25

Heart risk

Filed under: Uncategorized — gasstationwithoutpumps @ 18:11
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My 90-year-old father recently needed several stents installed, because his coronary arteries were 85–95% blocked. This came as a bit of a shock to the family, as we had thought his heart was in good shape (aside from needing a pacemaker). So I’ve been thinking a bit about my own risk of coronary vascular disease (CVD), especially since I have hereditary high cholesterol (from my Mom’s side of the family).

Like any modern academic, I turned to the web for more information. There are many calculators on the web for computing one’s risk of CVD, almost all claiming to be based on the Framingham study of heart health. Unfortunately, they disagree enormously (by  a factor of 2) on what my risk is.

I used the following statistics for all site: age 62, male, cholesterol 161 mg/dL=4.16mmol/L, HDL 43 mg/dL=1.11mmol/L, triglycerides 90 mg/dL=1.016 mmol/L, BP134/83mmHg, height 5’11” (180cm), weight 163 lbs(74 kg), race white, no treatment for blood pressure, non-smoker, and no diabetes, though these numbers are not all from the same day, and I’m doubtful of the blood-pressure reading, as it was done with a cheap home cuff that I don’t believe handles my low heart rate well.  (When I’ve had oscillometric and auditory measurements made at nearly the same time, the oscillometric ones have been substantially higher.)

I got the following risks of CVD in the next 10 years:

Site Risk  9.7%  10%  10% (using lipids), 17.9% (using BMI)  10.1% (heart attack or stroke)  10.1%  10.1%  10.1% 10.1%  11.4%  15.4% (Framingham), 11.6% (Qrisk2), 10.3% (ACC/AHA ASCVD)  12% (CHD), 5% (MI), 3% (CHD death), 3% (stroke), 18% (**CVD),  4% (**CVD death), 14% (JBS CVS Risk)  13%  15.0%  18.4%

I’ll have to ask my doctor whether it is worth getting a high-sensitivity C-Reactive Protein (hsCRP) test for inflammation to use one of the risk calculators that takes inflammation into account.

The risks are about normal for my age, but I’d like to reduce them if I can.  I’m already on statins (and have been for 25 years) and 81mg aspirin (self-prescribed), I already get about 150 minutes a week of moderate exercise, and I’ve been controlling my weight (though I’ve put on 4 lbs in the past year that I’d like to get rid of).  I’m not sure how much more I can reduce the risk.

2016 November 22

Black Friday sale 2016

Filed under: Circuits course — gasstationwithoutpumps @ 20:29
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Although I personally celebrate Buy Nothing Day this Friday, I have bowed to the marketing wisdom of the LeanPub publishers and am having a sale on my book this weekend.  From 2016 Nov 25 until 2016 Nov 29, the coupon link

will reduce the minimum price of my book from $3.99 to $2.56, approximately a 36% discount!  (At other times, it will just offer the usual pricing.)

Once you’ve bought the book, you can download any future versions that I publish through LeanPub (and I expect to have at least one more version before classes start in January).

Note: I’ll be sending coupons for free copies to the students registered for the course some time in December, so they don’t need to spend even the $2.56 of the Black Friday discount.

2016 November 19

Electronics course over-enrolled

Filed under: Circuits course — gasstationwithoutpumps @ 22:35
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Course registration has been going on for next quarter, and my Applied Electronics for Bioengineers course has more students wanting (or needing) to take it than we had planned for.  The largest previous class was last spring, with 45 students, so I had planned for a modest increase to 66 students this year (3 lab sections of 22 students each).  That filled up before the first round of registration was over, so I squeezed in 6 more students making room for 72 students (3 lab sections of 24 students each).  Those slots are now full and there are 12 students on the waiting list.  I can’t increase the lab sections any more (24 students in the lab is already crowded as there are only 12 benches).

I can’t add another lab section for several reasons:

  • The lab space is shared with another class that has 86 students enrolled (with a capacity of 120) and it took a while to negotiate even the 6 weekly slots for my 3 sections.
  • My lecture hall only seats 75.  Somewhat surprisingly, there are a couple of larger halls available in the MWF 2:40-3:45 time slot, though only one is a reasonable walking distance from my office (particularly given the amount of stuff I often carry to lectures for demos).  (If I’d been looking for a T Th slot, it would have been impossible at most times, as all larger halls are already scheduled.)
  • I’m already scheduled for classes, meetings, labs, or office hours 25 hours a week, not counting my Academic Senate committee or my undergrad directors’ meetings (which haven’t been scheduled yet).  I’ll probably be in the instructional lab TTh 1pm–7:30pm, making my lab hours be 13 hours a week.  (Students will have 190 minutes a week of lab, but there are three back-to-back sections, plus I need to set up and clean up.)
  • I don’t have a TA, so I’ll be doing all my own grading (8 problem sets and 5 large design reports for this course, and 2-3 design reports for the freshman design seminar). I will be able to hire undergraduate group tutors to help me answer questions in the lab—having two people in the lab to ask questions of makes a big difference.  I think I’ve got three tutors (one per section) lined up, but the official hiring doesn’t happen until some time in December.

The problem comes from a combination of factors:

  • requiring this electronics course of all bioengineering students (to reduce the pressure on the EE circuits course)
  • growing enrollment in bioengineering
  • growing enrollment at UCSC generally, without corresponding growth in instructional resources (instructional labs, classrooms, TAships, … )
  • my deliberately not  taking up a TAship for this course in previous years, to free up scarce teaching resources for more junior colleagues (though I fear that some of these resources have been squandered on courses taught by other senior faculty who didn’t really need TAs for their classes that were small or had only modest grading loads).

It looks like next year we’ll have to plan around 100 students:  the 84 students that seem to be the steady-state demand, plus 12 left over from this year, plus a tiny amount (probably too little) for growth.  That means that I’ll need 5 lab sections of 20 next year (or, with squeezing, 4 sections of 24).  I don’t think that I’ll be able to do all the grading myself for that large a class, particularly not with supervising that many labs.  So I’ll probably need a TA, who will have to come from another department, as none of the grad students in our department have electronics expertise. I might be able to get by with undergraduate group tutors and graders (though I’ll need enough hours from them that this might run into union limits—I believe the TA union considers it improper to have more than 20 hours a week of undergrad assistance).


2016 November 15

Not getting a new MacBook Pro

Filed under: Uncategorized — gasstationwithoutpumps @ 21:40
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My old MacBook Pro (late 2009 model) has been failing for the past few months (the SD card reader no longer works, the battery only lasts about 2–3 hours, the case is now failing in a way that exposes the electronics, …), and so I was planning to get a new MacBook Pro when the 2016 models came out.

But having seen the descriptions of them online and the prices, I’m not very enthusiastic about the new laptops.  One problem is the USB-C-only approach.  This video sums up my attitude:

(My wife says that the real story of the video is a restaurant worker who lost all the paella pans to the tide after leaving them on the beach.)

Other problems for the new MacBook Pro include the small sizes for the RAM and SSD drives  (my current laptop has 735GB of files on it and 8GB of RAM, so a new one would not be more capacity). Maybe I’ll wait a year to see if they can get a decent price/performance ratio on them.I’m also not excited about the low-travel keyboard, and the large trackpad might make it difficult for me to type, as I often rest the heels of my hands on the case, just a little outside the old, smaller track pad.  So the machine description did not make me want to rush out and spend a couple of grand on a machine that I may be unhappy with.

But my laptop is unlikely to survive another quarter, much less another year, so I’m faced with a bit of a dilemma, as I need a functioning laptop for giving lectures—particularly for demoing PteroDAQ and gnuplot.

I had recently bought the household a refurbished MacBook Air for travel (11″ early 2014), as my laptop is a bit too heavy for convenient travel, and my wife prefers a small laptop to an iPad (which we don’t have). Today, my wife suggested that I use the tiny MacBook Air for lecturing, and get another iMac as a desktop machine (we already have a mid-2011 iMac). The MacBook Air is sufficient for lecturing and travel—it has a couple of USB-A ports, so I can use flash drives or run PteroDAQ or the BitScope USB oscilloscope for lectures, and it has a mini-display port, so I can use my existing VGA dongle to connect to the classroom projector (which is VGA, not HDMI, according to the website of classroom media capabilities—I’d better double-check IRL).

If I decide to use the MacBook Air for lecturing, I can set it up over Winter break with all the software I’ll need and not worry about replacing my MacBook Pro for a few more months.

And then I probably will get an iMac. I can get much more machine for the money buying an iMac rather than a MacBook Pro, but I’ll have to think about exactly which iMac to get. Currently I’m leaning towards a 27″ retina display  model with an i7 processor, but I’ll have to look at prices and specs a bit more.  I’ll want a machine that will not cost more than about $500/year, amortized over its usable life, and preferably a little less.  There is a tradeoff between getting a high-performance machine that will be usable for a year or two longer, or a refurbished machine that has somewhat lower performance but can reasonably be replaced sooner.

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