Sugar v fat

▼ Yesterday, BBC 2 broadcast Sugar v Fat, a one-hour show about two identical twin doctors trying to figure out what is worse: eating a lot of sugar (well, carbohydrates in general) and almost no fat, or a lot of fat and almost no carbs.

They both ate as much as they wanted to, and they both lost weight. The fat doctor lost 3.5 kg: 1.5 kilos of fat and 2 kilos of muscle. The sugar doctor lost less, only 1 kg, with half of that being fat and the other half muscle. Interestingly, the sugar-eating doctor produced more insulin, but the fat-eating doctor actually had higher blood sugar. The sugar doctor also did a lot better with exercise.

Obviously a sample set of two doesn't prove much, but research on rats shows the same results: when given fat or sugar, the rats don't really gain weight. But if you give them a combination of fat and sugar, they do overeat and gain weight.

It works the same way for humans: nobody is interested in eating a stick of butter or a handful of sugar cubes, but put them together and you basically have ice cream. It looks like a combination of 50% carbohydrates and 50% fat is our kryptonite. A lot of hard-to-resist "bad" foods have this ratio, such as glazed donuts. But foods found in nature don't, maybe with the exception of some types of nuts.

This may be why the people who are against processed foods have a point. We humans can barely survive off of raw food; processing, also known as "cooking", allows us to eat a lot of food that we otherwise wouldn't be able to digest very well. But combining carbs and fats into chips, donuts, cheesecake, ice cream, chocolate and so on was probably not the best idea, health-wise.

Permalink - posted 2014-01-30

Why another DSLR?

▼ I'm probably going to get a new Nikon digital single lens reflex (DSLR) camera. You know, those big cameras that let you attach different kinds of lenses. Even though I got a new regular point-and-shoot (P&S) camera this summer, and my iPhone also takes very nice pictures. So why another DSLR?

First, let me agree with Ken Rockwell up to a point: Your Camera Doesn't Matter.

For example, when I was in New York in 2005 I had a 2 megapixel point-and-shoot camera. I took the ferry to Staten Island to get a look at the city from the water, and was returning to Manhattan around sunset. The ferry gives you a pretty good view of the Statue of Liberty:

So I waited for the right moment and took this photo:

In 2011, I had a 12 megapixel DSLR. It got stolen on christmas day at a highway rest stop between Madrid and Barcelona. Then we came upon the Greenwich meridian around sunset. (Hm, do I detect a common theme?) So I took this photo with my 5 megapixel iPhone 4:

In both cases, I had tricky light to work with and was on a moving vehicle, so I had to wait for the right moment to take the picture. I'm very happy with both these photos. Would they have been sharper with better cameras? Sure. But would that have mattered? Not really. And maybe I would have been tempted to use more advanced settings and screwed up the shot.

Every camera you can buy today—including those in phones—has enough megapixels and a sufficiently good lens to take very good pictures in daylight outdoors. As long as you stick to small things close by, medium-sized things at medium distances, or large things at large distances and those things don't move very fast. So you're not going to get the following shots.

Small things at a distance, such as this red-winged starling at the Cape of Good Hope:

Some kind of power or communications station in the dark:

What these photos require are a zoom lens and/or manual exposure settings. Although these two were taken with a DSLR, they could have been taken with a point-and-shoot camera. But then there's the ones below.

Small things moving very fast in low light, such as bats above the parking lot:

Large things from up close: the whole skyscraper from right in front of the entrance:

Although there is no fundamental reason why a P&S can't have the same low-light capabilities as a DSLR and/or focus and shoot as fas as a DSLR, in practice DSLRs perform much better in these regards than reasonably priced P&S cameras. The same thing for lenses: there are point-and-shoots with very capable zoom lenses and ones with lenses that work well in low light, but with a DSLR you don't have to choose or compromise, you can get the most extreme lens imaginable and simply replace it in seconds when your needs change.

And that's why I think I still need that DSLR: for the bats, the skyscrapers and the like. And to not have to use a flash on people that just won't sit still when I want to take their picture indoors at night.

Permalink - posted 2014-01-26

The state of enhanced podcasts

▼ A long time ago Apple introduced "enhanced" podcasts. These are audio podcasts with chapters, where each chapter optionally has an image and/or a URL. It's a very nice idea, but enhanced podcasts never gained much traction, probably for three reasons:

• Few people care, you typically listen from start to finish without looking at your computer/phone/iPod screen
• The audio needs to be in MPEG4/AAC format rather than MP3, so there are one or two players that are incompatible
• There are no good tools to create enhanced podcasts

David Jackson thinks they're lame. I've never had a podcast of my own, although I've thought about starting one many times. But I have recorded a few presentations over the years and then added images of the slides I used as chapter images, like on the one I did last week.

I can see Jackson's point, but I disagree. First of all, I'm pretty sure that even outside the Apple universe MPEG4 audio is now so widely supported that it's not really necessary to have a separate MP3 version. And because I also value the ability to listen to podcasts while doing other things, I really don't like video podcasts, which require you to sit in front of your screen. Enhanced podcasts provide an extra visual channel without getting in the way.

It's too bad that enhanced podcasts are one of those things that Apple has let slide as they focus on other things. They used to have a "chapter tool" for creating enhanced podcast on the command line, but it no longer works. All podcast support was removed from Garageband, but I disliked the previous enhanced podcast support anyway because Garageband only allowed for low resolution images.

I did find a very useful web service that lets you make enhanced podcasts, though: Auphonic. I recorded the audio for my presentation with my iPhone through the headphones microphone using the built-in Voice Memos application. Keynote (on the Mac) can also record your presentation as you're delivering it, but unfortunately you can then only export it as a (very large) QuickTime movie, not as an enhanced podcast.

As for playing back enhanced podcasts, the new iTunes 11.1 doesn't support enhanced podcasts. Update: that's not completely true. Even though iTunes 11.1 doesn't display the images attached to chapters in any of the places where you normally see album artwork (such as the MiniPlayer), when playing an enhanced podcast iTunes has a "chapters" menu in the menu bar that you can use to navigate the chapters of the enhanced podcast and there are menu options with keyboard shortcuts to skip to the previous/next chapter in the "controls" menu. Also, the title of the current chapter is displayed in the main iTunes window during playback.

The QuickTime Player and Safari do, though. And the AppleTV plays the really well, but as far as I can tell only when streamed from the iPhone. The Podcasts application on the iPhone does support enhanced podcasts, but the text on my slides is really too small to be legible because the landscape slides are displayed in portrait, and when selecting chapters the chapter names are missing. And many but not all third party iOS podcast playing applications support enhanced podcasts.

If you want to see enhanced podcasting in action, subscribe to the Macworld Podcast.

Permalink - posted 2014-01-15

The free will paradox

▼ Do we have free will or not? I just watched this video on Youtube: Sam Harris on "Free Will".

I was somewhat dismayed to hear Sam Harris reject the notion of free will so easily. (He did get in a few good jokes at the expensive of religion, though.) Dismissing free will seems to be in vogue these days, based on the issue that it's hard to square free will with a deterministic universe and also with experiments that can predict what subjects are going to do before they're aware that they've made a decision.

The paradox is that if there's no free will, why do we torture ourselves trying to make good decisions? It certainly seems that we have free will!

This is a fascinating topic that resists easy answers. It starts with defining what free will really is. Intuitively, it seems to have something to do with conscious decision making, opening the door towards the problem of consciousness, an even tougher nut to crack.

We certainly do have free will in the sense that it is possible for us to farm out some decisions to our consciousness. (Although a depressingly large part of our decision making happens subconsciously.) For instance, suppose we want to invest € 3250 for a year. There are two options: one with a 3% return and € 50 costs, while the other has a 4% return and € 85 costs. Most of us will not be able to determine which investment has a higher net return without consciously doing the arithmetic. So if we decide to go for the best return, we have to do the calculations to determine that the first one pays out € 47.50 and the second € 45 and then we can select the first option. In this case the timing of the whole process is irrelevant.

Could it be that this is why we have consciousness and that we feel anxious about making important decisions: we need the consciousness to run algorithms that our subconscious is incapable of, and the anxiousness is simply the (deterministic?) trigger to get us to spend the time and energy to do so.

Permalink - posted 2014-01-11