Trance opera—Spente le Stellebe dramatic

# a rat: fun

Workshop at Brain and Mind Symposium, Långvik Congress Center, Kirkkonummi, Sep 17–18 2015.

# Alex — Internet's Most Popular Rat

## Poster Rat for Rat Genome Sequencing

The rat genome sequencing project at the Baylor College of Medicine Human Genome Sequencing Centre is complete. The genome has been analyzed and published.

I'd like to introduce you one of the faces of the project: Alex, the genomics rat idol.

Arguably, Alex is the most popular rat on the internet. For the justification of this strong statement, read on.

Alex, the rat. Rattus norvegicus on an ABI 3700 genome sequencer. (zoom)
Alex, the rat. Rattus norvegicus on an ABI 3700 genome sequencer. (zoom)

## Alex's Biography

Alex was born in May 2000. It's well known that a rat's cuteness reaches maximum at about 3-4 weeks. After this critical time, a pet store rat is less likely to be purchased and may be asked to act as snake food. In Alex's case, she was perilously close to her deadline. Luckily for her, we paid a ransom of \$6.99 to the Noah's Ark pet shop in Vancouver. She was on her last cute leg.

Portrait of Alex, the genome rat (Rattus norvegicus). Here, she is seen in a forced portrait position (zoom)

From May 2000 Alex spent most of her time hoarding food pellets and riding on shoulders.

Portrait of Alex, the genome rat (Rattus norvegicus). Riding on shoulder.

Alex liked to bite. And rats only bite hard — they don't nibble. Her contention for this unattractive behaviour was the uncanny similarity between a finger and a pellet of food.

Other than unpredictable bouts of biting (by far the most exciting aspect of her personality), Alex lacked other distinguishing characteristics.

Alex died of a seizure in late 2002. She was buried outside of the Museum of Anthropology. A ratty pair of underwear served as a burial shroud.

And I hope you got that last pun.

Photos are for public use. Use, modification and distribution of these photos is unrestricted.

## Alex's Popularity

Despite my best efforts at meaningful work, this web page continues to be the most popular of all my online offerings, making for a somewhat embarrassing achievement.

Alex's images consistently show up first in Google's web search for 'rat', 'rat image' and image search for 'rat'.

Alex image is the first for Google's 'rat' search query (retrieved 16 Mar 2013). (rat Google search)
Alex image is the first for Google's 'rat image' search query (retrieved 16 Mar 2013). (rat Google search)

Finally, Alex appears as the first entry in Google images for 'rat'.

Alex image is the first for Google's 'rat image' search query (retrieved 16 Mar 2013). (rat Google search)

## Alex's Public Appearances

Alex is neither without modesty nor public fame. Her first cover-ratgirl appearance was on the April 2004 issue of Genome Research.

Alex the rat appeared on the cover of Genome Research (April 2004). (zoom)

More recently, she's appeared on the cover of Ethnologie Francaise (Jan-Mar 2009 issue).

Alex the rat appeared on the cover of Ethnologie Francaise (1/2009). (zoom)

The topic of the issue was the relationship between animals and humans. It is fitting therefore to recount here the relationship I shared with Alex during her sojourn with us.

# Bayesian statistics

Thu 30-04-2015

Building on last month's column about Bayes' Theorem, we introduce Bayesian inference and contrast it to frequentist inference.

Given a hypothesis and a model, the frequentist calculates the probability of different data generated by the model, P(data|model). When this probability to obtain the observed data from the model is small (e.g. alpha = 0.05), the frequentist rejects the hypothesis.

Nature Methods Points of Significance column: Bayesian Statistics. (read)

In contrast, the Bayesian makes direct probability statements about the model by calculating P(model|data). In other words, given the observed data, the probability that the model is correct. With this approach it is possible to relate the probability of different models to identify one that is most compatible with the data.

The Bayesian approach is actually more intuitive. From the frequentist point of view, the probability used to assess the veracity of a hypothesis, P(data|model), commonly referred to as the P value, does not help us determine the probability that the model is correct. In fact, the P value is commonly misinterpreted as the probability that the hypothesis is right. This is the so-called "prosecutor's fallacy", which confuses the two conditional probabilities P(data|model) for P(model|data). It is the latter quantity that is more directly useful and calculated by the Bayesian.

Puga, J.L, Krzywinski, M. & Altman, N. (2015) Points of Significance: Bayes' Theorem Nature Methods 12:277-278.

Puga, J.L, Krzywinski, M. & Altman, N. (2015) Points of Significance: Bayes' Theorem Nature Methods 12:277-278.

# Bayes' Theorem

Wed 22-04-2015

In our first column on Bayesian statistics, we introduce conditional probabilities and Bayes' theorem

P(B|A) = P(A|B) × P(B) / P(A)

This relationship between conditional probabilities P(B|A) and P(A|B) is central in Bayesian statistics. We illustrate how Bayes' theorem can be used to quickly calculate useful probabilities that are more difficult to conceptualize within a frequentist framework.

Nature Methods Points of Significance column: Bayes' Theorem. (read)

Using Bayes' theorem, we can incorporate our beliefs and prior experience about a system and update it when data are collected.

Puga, J.L, Krzywinski, M. & Altman, N. (2015) Points of Significance: Bayes' Theorem Nature Methods 12:277-278.

Oldford, R.W. & Cherry, W.H. Picturing probability: the poverty of Venn diagrams, the richness of eikosograms. (University of Waterloo, 2006)

# Happy 2015 Pi Day—can you see pi through the treemap?

Sat 14-03-2015

Celebrate pi Day (March 14th) with splitting its digit endlessly. This year I use a treemap approach to encode the digits in the style of Piet Mondrian.

Digits of pi, phi and e. (details)

The art has been featured in Ana Swanson's Wonkblog article at the Washington Post—10 Stunning Images Show The Beauty Hidden in pi.

I also have art from 2013 pi Day and 2014 pi Day.