Category: Science

New discoveries, the scientific method, and all matters relating to the scientific study of the physical world

Software defined radio

Software defined radio (SDR) is one of the things I am most curious about. There is just so much data being exchanged via radio these days. It’s strange to think about the constant complex pattern of broadcasting happening all around us.

This video gives a bit of a taste of what is happening in one part of the world and across a fairly narrow range of frequencies:

It’s pretty cool that he is able to identify and analyze Chinese over-the-horizon RADAR. It shows some of the possibilities SDR opens up for hobbyists.

Much of the hardware required to seriously experiment with SDR is expensive. Interestingly, though, someone has figured out how to do the job for the 64-1700MHz frequency band using an $11 digital TV tuner chip.

You could do some very cool stuff with this: set up your own infrastructure independent computer networks, explore what sort of communication is happening around you, conduct intrusion detection (looking for interception devices broadcasting), and experiment with the security of your hardware, such as the Bluetooth chips in your phone and laptop.

Open thread: Antibiotic resistance

I frequently see interesting stories about antibiotic resistance, and it seems to be quite an important issue. Back in 2008, I wrote about a Canadian initiative to try to deal with the dangerous bugs.

More recently, tuberculosis has progressed from extensively drug-resistant TB (XDR-TB) to “totally drug-resistant TB” (TDR-TB).

We are going to need some new antibiotics.

2012 vernal equinox

The coming of spring is an astronomical and biological phenomenon.

The moment of the vernal equinox – the start of spring in the northern hemisphere – is the moment where the length of days is changing fastest. Biologically, spring is characterized by the re-emergence of life. In particular, it is characterized by the resumption of productive photosynthesis as leaf-bearing plants deploy their solar collectors to take advantage of longer days. This process, along with organic decay during the darker months, gives the Keeling Curve its characteristic wiggles.

In a way, each spring is a dawn for renewable energy. Aside from a few chemical-eating bugs in the ocean, pretty much all life on Earth is ultimately powered by sunlight as processed by photosynthetic organisms. Spring shows how the vast energy output of the sun can be used in the service of life.

We’re made of cheap stuff

As a child, I visited Vancouver’s Science World on what was probably a monthly basis. I knew most of the stage shows by heart (‘Arcs and sparks’ was the most energetic, complete with exploding pickle), along with the dramatic vocal introduction at the OMNIMAX theatre.

One display I remember well was located in the main atrium area. It was a scale that weighed you and then told you in a robot voice how much it would cost to buy lab-grade versions of all the chemicals that comprise you. It would say: “You contain $1.24 worth of carbon” or “You contain $0.03 worth of iron”. At the end, it said that you had a monetary value of X amount “give or take a few cents”.

In a way, the display illustrates that is remarkable about biology. You can take utterly mundane stuff – air and soil – and turn it into astonishingly complicated chemicals and structures, everything from the complex fragrances of flowers to DNA to the core of an oak tree to a human brain. Botany and plant cultivation are a kind of alchemy precisely because of how they allow the transformation of garden-variety raw materials into complex products. You can have all the materials necessary to make a wombat, but there is really no way to put them together in the right way unless you have a couple of fertile wombats on hand as well.

The same reality intersects with the practice of organ donation. Right now, a mass of a few kilograms located inside my thoracic cavity might be a highly-valuable liver or kidney. Without the benefit of a functioning circulatory and immune system – or, failing that, proper care and refrigeration – it becomes a near-worthless lump of meat in just a few hours. We’re made of cheap stuff; the added value is in the organization.

Lark sleep monitor

For the past couple of months, I have been using a Lark sleep monitor. It’s an accelerometer that you wear on your wrist at night that interfaces with your iPhone. It both works as an alarm clock and as a measuring device that provides data on the length and quality of your sleep. You set when you want to wake up and it wakes you at that time with nearly silent vibration (and a backup sound alarm from the phone).

The device has a few obvious uses. If two people sleep in the same bed but normally wake at different times, the Lark would allow one to more easily wake on time without waking the other. The Lark also lets you collect statistics about yourself, and evaluate how well you sleep in different environments and conditions.

For instance, I slept for an average of 8:41 per night when on vacation at my aunt and uncle’s very quiet house in Bennington, Vermont (with one early morning on December 25th). That compares with an overall average sleep time of 7:45 over the past couple of months.

So far, I have collected data for 86 days. More accurately, I have data for 81 of those days and null values for the five days when I wasn’t able to use the Lark – for instance, because I was taking an overnight Greyhound.

My recent sleep stats

This table shows some simple summary statistics:

Mean Median Standard deviation
Time asleep 7:45 7:56 2:00
Sleep quality 8.5 8.7 0.84
Fell asleep in 0:37 0:30 0:34
Woke up (# of times) 18.9 18 6.39

 

In blue, this time series shows time spent asleep. In pink, it shows how much time was spent falling asleep:

This is a histogram of time spent asleep:

And this shows the frequency of the different qualitative sleep ratings assigned by the Lark software:

The Lark software informs me that the amount of time it takes me to fall asleep “needs work”, as does the number of times I wake per night. My overall length of sleep and sleep quality it deems “OK”.

The biggest thing that jumps out at me from my own data is the sawtooth pattern of sleep. I tend to alternate between a night with relatively little sleep (about six hours) and a night with relatively much (about nine hours). Given that I usually need to wake up at 6:30am or 6:45am, these correspond to nights when I go to sleep around midnight and others where I collapse around 9:00pm or 10:00pm.

Remember, the Lark distinguishes between time spent falling asleep (the period before the first time of prolonged stillness detected by the Lark) and time spent actually asleep. A night recorded as eight hours of sleep is therefore a night with eight hours of stillness comparable to that of sleep, rather than a night when you spend eight hours in bed. Being able to distinguish those two things may be the most valuable thing about the Lark.

Evaluation of the Lark

Overall, I think the Lark works very well. It has never failed to wake me up, and the iPhone software works well.

One suggestion to all iPhone owners is to put your phone in ‘Airplane mode’ at night. That way, it doesn’t beep or buzz when you get late-night texts and emails. You can still use the Lark in this mode, but you do need to follow a simple procedure:

  1. Set the iPhone to ‘Airplane mode’
  2. Manually turn Bluetooth back on
  3. Connect to the Lark
  4. Set your alarm time in the Lark software
  5. Sleep, and be woken

One useful feature the makers of the Lark could add would be the ability to set pre-programmed alarms for different days of the week. For example, you might set your default Monday-Friday alarm for 6:30am or 7:00am, but your weekend alarm for a more reasonable 9:00am or 10:00am.

One side note: it is easy to transfer the basic sleep data from the Lark into your preferred statistical analysis software. For people who don’t want to do that, the company sells an absurdly overpriced (US$$159!) subscription service that keeps track of your data for you online and provides ‘coaching’.

Googling the Cyborg

In his engaging essay “Googling the Cyborg”, William Gibson effectively argues that the expectation that ‘the cyborg’ will be a human being with an electronic eye and a robot arm is mistaken. The cyborg – he argues – exists in the physical interactions between human beings and machines: “The electrons streaming into a child’s eye from the screen of the wooden television are as physical as anything else. As physical as the neurons subsequently moving along that child’s optic nerve”. (The terminology there is strangely incorrect. Cathode ray tube televisions emit photons, which are produced when the electrons fired from the back of the vacuum tube hit a phosphor screen – and the optic nerve is made of neurons, it isn’t a channel that conveys them. No matter.)

Gibson argues that the cyborg is the “extended communal nervous system” that humanity has grown for itself, with all these sensors and processors and network connections.

He also argues that there is a short-changing that occurs, when we deny that the humans who are behind machines are using them as true extensions of their own being. In the context of remote-controlled rovers on Mars, he says:

Martian jet lag. That’s what you get when you operate one of those little Radio Shack wagon/probes from a comfortable seat back at an airbase in California. Literally. Those operators were the first humans to experience Martian jet lag. In my sense of things, we should know their names: first humans on the Red Planet. Robbed of recognition by that same old school of human literalism.

Gibson, William. Distrust that Particular Flavor. p.251 (hardcover)

I am not sure what should be counted as the first cyborg on Mars. Specifically, did it need to be able to move on human command? Or is moving camera shutters enough to count? In any case, hardly anyone knows the name of the person who was controlling it when it first activated on the Martian surface.

Meteorologists on climate

The other day, I saw a Vancouver Sun article called “Meteorologists split on global warming“.

I was struck in particular by the sub-headline: “Fewer than one in five specialists in the U.S. see human influence as the only driver”.

At first glance, may seem like a garden-variety example of climate change skepticism from experts in fields other than climatology. People who are experts in one area often have misplaced confidence about their expertise in others.

On second reading, the sentence betrays considerable ignorance about the subject of climate. If “19 per cent of U.S. meteorologists saw human influences as the sole driver of climate change in a 2011 survey” then at least 19% of U.S. meteorologists have no idea what they are talking about.

Nobody is arguing that human behaviour – or CO2 emissions exclusively – is the only thing that affects the climate. Look up the concept of ‘radiative forcing‘ and you will quickly learn that scientists have studied many of the causes of climate change in detail. The work of the Intergovernmental Panel on Climate Change (IPCC) has involved consideration of other things. They looked at impacts from changes in ozone, albedo (the reflectiveness of the Earth’s surface), aerosols, linear contrails, and changes in the energy output of the sun. When you look at all of these factors, you see that greenhouse gases are simply the most important cause of change in the climate right now, and we are poised to emit vast additional quantities of them as the world continues to burn fossil fuels.

Gabor Maté on addiction and drug policy

Please listen to this podcast:

Gabor Maté on The Human Face of Addictive Behavior

Maté makes some excellent points about the psychological basis for addiction, as well as the serious problems with our current approach of treating addiction as a crime.

Maté makes a powerful case that criminalization of drug use is ineffective and unethical, and that we could do much more to lessen human misery by pursuing harm reduction approaches.

[Update: 28 Oct 2020] Broken link replaced