Friday, August 30, 2013

Removing Pdf/A protection in adobe acrobat

Are you also annoyed with the fact that you cannot highlight text or insert comments in certain pdf files i.e., pdf/a? The following two steps will allow you to get rid of this protection.

1. Export the pdf A file as a Postscript
2. Open the Postscript file and print it as a pdf file

And there you go, open the new pdf file and make all the highlights/comments you like.

Tuesday, August 27, 2013

Benefits from playing action video games

I just finished reading a recent review by Dapne Bavelier about the benefits of playing action video games. This review does not address the controversial issue of whether video games cause people to become more violent or not (I am personally on the fence on that one).

Rather, this review focus on the effects on more basic perceptual processes, and how playing video games affects these abilities. All this is put within a "learning to learn" framework. That is, will playing action video games help you find patterns or gain knowledge when you are not playing video games as well.

The pattern is very clear here. Video games will help you in a number of different ways. People who play action video games (sim city or civilization won't do), are faster at identifying objects, without making more errors, there are not as easily distracted by irrelevant stimuli, and they have greater contrast sensitivity. It seems as though video games enhances eyesight in general.

There are also substantial benefits in certain cognitive functions. People who play action video games enhance their ability to perform mental rotations (ex determining which 3D shape matches another 3D shape). Mental rotation in turn correlates with improved mathematical skills. Multi-tasking is another cognitive function that is improved in video game players.

Significant improvements have also been seen in decision making and reaction times. These factors may determine whether you brake in time to prevent a traffic accident or whether you die.

Thus in general, playing action video games improve a broad range of perceptual/cognitive abilities which probably helps the individual find relevant information in the environment, even though that environment does not involve war.

The objection which I am sure that some of you have thought of already is the classic "correlation does not equal causation". Maybe people who are good at all of these perceptual/cognitive tasks to begin with like video games more and therefore play more. Indeed, it you are slow, you get killed a lot in many of these games which can be very discouraging (I have played a little bit online and it sucks when you get shot 30 times over by a ten year old).

Researchers of course anticipate this objection and therefore conduct controlled studies. For instance you can take a random group of student with equivalent video game experience and then pay them to play either call of duty or civilization (a turn based game) for a few hours per day for a week or so. Differences between these groups after the intervention are probably due to the different treatments. Such controlled studies support the conclusions above, video games really do improve perceptual/cognitive functions.

So depending on whether you think action video games will increase aggression (like I said, I think the jury is still out on that one), if your child is playing violent video games and still not missing out of school etc, then you might even want to encourage this.
Bavelier D, Green CS, Pouget A, & Schrater P (2012). Brain plasticity through the life span: learning to learn and action video games. Annual review of neuroscience, 35, 391-416 PMID: 22715883

Monday, August 19, 2013

How fast are audible books read?

Since my life involves many tasks that are very tedious, but can be done in an incognizant state of mind I tend to listen to many podcasts and audiobooks. That tedious work such as cleaning, washing up or walking the dog becomes an opportunity to learn instead of just a waste of time. I recommend this approach to every dad who feels under-stimulated when at home (not a prerequisite to be a dad of course).

Anyway, I was curious to know how many pages one hour of listening corresponds to and therefore I decided to do a small study on the books that I have listened to the past year. You can find the complete list of books that I have listened to below. The first column gives you the title of the book, the second gives you how many pages the book is (gathered this data from The third column gives you the reading pace for that particular book i.e., pages per hour.

I will give the most important statistics here. In total I have listened to audiobooks for a total of 284 hours this past year. This amounts to 5.5h per week or 0.8h per day. These 284h were spent listening to a total of 24 books, totalling 8469 pages. This amounts to 163 pages per week or 23 pages per day.

So what about the reading pace? To get the average number of pages you get through in an hour one can merely divide the total number of pages with the total listening time, 8469/284 = 30. That is, the average reading speed of audible readers is about 30 pages per hour, with a range from 22,2 (The 2nd world war by Anthony Beevor), to 54 (The science of evil by Simon Baron Cohen). The standard deviation was 7.79 pages per hour.

Here is the entire list of books I have listened to the past year, as well as the number of pages, the duration of the audibook and the average reading pace of that book:

Blood and thunder 499 21 23,76
Energy for future presidents 305 9,5 32,11
The Universe within 191 6,5 29,38
How pleasure works 223 7 31,86
Thinking fast and slow 483 20 24,15
We are anonymous 428 14 30,57
Half the sky 259 10,5 24,67
Bad astronomy 259 9,5 27,26
Naked statistics 257 11 23,36
Drinking water 320 8 40,00
Genghis Khan 352 14,5 24,28
The Moral Lanscape 320 7 45,71
At home 592 16,5 35,88
Radiation 288 7,5 38,40
The world until yesterday 512 18,5 27,68
Complications 269 8 33,63
The undercover economist 265 8,5 31,18
The willpower instinct 272 8,5 32,00
The science of evil 272 5 54,40
A history of the world in 6 glasses 311 7,5 41,47
God is not great 336 9 37,33
Incognito 304 9 33,78
The Second world war 880 39,5 22,28
Who's in charge 272 8 34,00

ps: An assumption of this analysis is that the number of words per page is approximately the same for different books - an assumption that is likely to be false for some books and may therefore bias the results.

Sunday, August 18, 2013

Review of Energy for future presidents by Richard Muller

I will start by admitting that I am a fan of Richard Muller. Before I even went to university I watched every lecture in his "Physics for future presidents" course at UC Berkeley, which was one of the first courses to become available online as a free webcast. I would describe Muller as an honest and rigorous scientist who is not afraid to speak his mind even when his views are controversial. He is also very critical of the way that different energy issues are portrayed in the media, something which you will realize if you read this book.


One good example of what can only be called overblown media reporting is what followed the BP oil spill in the Mexican gulf. When it happened the media was reporting on little else and many high standing politicians described it as one of the worst (sometimes the worst) environmental disasters in the history of mankind. What happened next? Suddenly the media moved on and I was surprised to learn (from this book) that though the initial explosion killed 11 workers, the subsequent oil spill only caused 6000-30.000 bird deaths. "Only" is indeed the appropriate term here, considering that glass windows kill 100.000.000 birds annually and power lines kill many million more. The BP oil spill was unfortunate, and it cost human lives, some birds and a lot of money to fix it, but it is clear that the media and the politicians got a bit carried away with this one.

Another so called " disaster" which got an unfair treatment in the media was the Fukushima power plant accident. To date not a single person have died from the radiation released and the prognosis is that a few hundred extra cancers, some of which could have a fatal outcome, will be the result of this “disaster”. My Fukushima headline would have read: “No deaths from breakdown of old nuclear power plant even though it was hit with an 8.0 earthquake and a tsunami”... (also see my pre-fukushima post on the irrational fear of nuclear power as well as my Review of the book “Radiation”).

Richard Muller spends a good deal of this book discussing the ever controversial topic of Global Warming. He was at a point very critical of the methodology used by climate researchers when they calculated the rate of global warming. For example it is not appropriate to use weather stations in populated areas because as population grows so does temperature. He also found some of the mathematics used... funky...

For this reason he did his own study, and unlike IPCC researchers this study was/is completely transparent with all data freely available for anyone who desires to make their own calculations. What did Muller find? Basically he says that the IPCC, despite their sometimes flawed methods, are correct. In other words, according to Muller the globe has warmed, and this warming has been due to human caused increases in atmospheric CO2 levels. While backing their overall conclusions about the temperature increase on earth Muller does not seem to share many peoples sense of pending disaster due to this warming. Models that predict the future climate of earth tends to have a lot of uncertainty associated with them, and it is almost impossible to know if we are able to come up with technologies that will significantly alter the future climate.

He also says that if we really want to prevent increasing levels of carbon dioxide in the atmosphere we should turn our efforts to China. For quite a long time they have been building one coal plant per week spewing out not only CO2, but also huge amounts of other pollutants such as lead and arsenic. Convincing them to use clean energy sources such as solar or nuclear power (by paying them if necessary), makes a lot more sense than going for expensive alternatives in the west. That is, if you aim to achieve the maximal reduction of CO2 release per dollar, that dollar should be invested in China. Muller also reiterates several times throughout the book that energy conservation will be a huge part of the future. Proper isolation of houses, driving efficient cars etc can drastically reduce energy expenditure.

I have really only touched upon some of the issues that are discussed in this book. Muller offers a perspective on many other energy related issues such as Shale gas/oil, electric cars, fusion, wind/solar/water energy, etc etc. All in all this book is both very educational and at the same time a page turner (keep in mind though that I am kind of a nerd). If you are even just a little interested in the technologies and politics related to energy issues this book is a terrific buy!