2024 π Daylatest newsbuy art
Here we are now at the middle of the fourth large part of this talk.Pepe Deluxeget nowheremore quotes
science + music
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
ADSR Collective Segue- Gene Machines [ADSR010] - clips

The cover of the album is based on my information graphic of gene expression designed for Scientific American Graphic Science.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The cover of Gene Machines shows expression profiles of a set of genes that cycle their activity throughout the day based on circadian rhythms.
An assembly of shifting soundscapes, textures and rhythmic loops produced by laboratory machines.
a bb 3000 micro centrifuge automation
b server room mini centrifuge thermal cycler
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The album features the sounds from around our laboratory including the Beckman Biomeck 3000 and Hamilton Starlet liquid handling robots, thermocyclers, centrifuges and our server room.

bb 3000

Curious machines explore the mysteries of a tumor cell. If you listen carefully, you can hear them hum to themselves and each other. It’s their way of talking.

micro centrifuge

A compact and low profile centrifuge with whisper-quiet operation and extremely fast acceleration and braking. The motorized latch secures the lid and rotary knobs allow fast parameter selection.

Relative centrifugal field (RCF) is the centrifugal force generated by a rotor of radius `R` (cm) spinning at a speed `S` (rpm). It is expressed in units of the Earth’s acceleration due to gravity, `g = 9.8 \, \text{m} / \text{s}^2` and given by `\text{RCF} = 1.118\times10^{–5}RS^2`


16,000 g


24 × 1.5/2.0 mL tubes


800–13,200 rpm


Robots automate liquid handling with interchangeable single or eight channel pipettes that can accommodate various tips. They are used to normalize samples, set up chemical reactions, or SPRI bead-clean samples prior to loading sequencers.


30 tracks


45 sec/cycle


10, 50, 300, 1,000 μL


1%, 0.75%, 0.75%, 0.75%

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The machinery of side A in detail.

server room

Computational pipelines and databases process more than 100 terabases of sequence per month.





Dell Intel E5

HPE E7 2.5Tb high-memory servers


24 PB

EMC Isilon X410

EMC A2000

NetApp 9000

DDN GS12K + GridScalar


40 Gbps

Brocade MLX Layer 2

Ruckus ICX Layer3

mini centrifuge

This compact centrifuge provide a quick method to spin down samples from the walls and caps of microcentrifuge tubes.


2,000 g


6 × 1.5/2.0 mL tubes


6,000 rpm

thermal cycler

The thermal cycler was instrumental to the Human Genome Project.It is used to amplify DNA libraries prior to loading onto DNA sequencers.


–5°C – 105°C




5' 95°C


60' 37°C

5' 70°C

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The machinery of side B in detail.
news + thoughts

Nasa to send our human genome discs to the Moon

Sat 23-03-2024

We'd like to say a ‘cosmic hello’: mathematics, culture, palaeontology, art and science, and ... human genomes.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
SANCTUARY PROJECT | A cosmic hello of art, science, and genomes. (details)
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
SANCTUARY PROJECT | Benoit Faiveley, founder of the Sanctuary project gives the Sanctuary disc a visual check at CEA LeQ Grenoble (image: Vincent Thomas). (details)
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
SANCTUARY PROJECT | Sanctuary team examines the Life disc at INRIA Paris Saclay (image: Benedict Redgrove) (details)

Comparing classifier performance with baselines

Sat 23-03-2024

All animals are equal, but some animals are more equal than others. —George Orwell

This month, we will illustrate the importance of establishing a baseline performance level.

Baselines are typically generated independently for each dataset using very simple models. Their role is to set the minimum level of acceptable performance and help with comparing relative improvements in performance of other models.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Comparing classifier performance with baselines. (read)

Unfortunately, baselines are often overlooked and, in the presence of a class imbalance5, must be established with care.

Megahed, F.M, Chen, Y-J., Jones-Farmer, A., Rigdon, S.E., Krzywinski, M. & Altman, N. (2024) Points of significance: Comparing classifier performance with baselines. Nat. Methods 20.

Happy 2024 π Day—
sunflowers ho!

Sat 09-03-2024

Celebrate π Day (March 14th) and dig into the digit garden. Let's grow something.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
2024 π DAY | A garden of 1,000 digits of π. (details)

How Analyzing Cosmic Nothing Might Explain Everything

Thu 18-01-2024

Huge empty areas of the universe called voids could help solve the greatest mysteries in the cosmos.

My graphic accompanying How Analyzing Cosmic Nothing Might Explain Everything in the January 2024 issue of Scientific American depicts the entire Universe in a two-page spread — full of nothing.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
How Analyzing Cosmic Nothing Might Explain Everything. Text by Michael Lemonick (editor), art direction by Jen Christiansen (Senior Graphics Editor), source: SDSS

The graphic uses the latest data from SDSS 12 and is an update to my Superclusters and Voids poster.

Michael Lemonick (editor) explains on the graphic:

“Regions of relatively empty space called cosmic voids are everywhere in the universe, and scientists believe studying their size, shape and spread across the cosmos could help them understand dark matter, dark energy and other big mysteries.

To use voids in this way, astronomers must map these regions in detail—a project that is just beginning.

Shown here are voids discovered by the Sloan Digital Sky Survey (SDSS), along with a selection of 16 previously named voids. Scientists expect voids to be evenly distributed throughout space—the lack of voids in some regions on the globe simply reflects SDSS’s sky coverage.”


Sofia Contarini, Alice Pisani, Nico Hamaus, Federico Marulli Lauro Moscardini & Marco Baldi (2023) Cosmological Constraints from the BOSS DR12 Void Size Function Astrophysical Journal 953:46.

Nico Hamaus, Alice Pisani, Jin-Ah Choi, Guilhem Lavaux, Benjamin D. Wandelt & Jochen Weller (2020) Journal of Cosmology and Astroparticle Physics 2020:023.

Sloan Digital Sky Survey Data Release 12

constellation figures

Alan MacRobert (Sky & Telescope), Paulina Rowicka/Martin Krzywinski (revisions & Microscopium)


Hoffleit & Warren Jr. (1991) The Bright Star Catalog, 5th Revised Edition (Preliminary Version).


H0 = 67.4 km/(Mpc·s), Ωm = 0.315, Ωv = 0.685. Planck collaboration Planck 2018 results. VI. Cosmological parameters (2018).

Error in predictor variables

Tue 02-01-2024

It is the mark of an educated mind to rest satisfied with the degree of precision that the nature of the subject admits and not to seek exactness where only an approximation is possible. —Aristotle

In regression, the predictors are (typically) assumed to have known values that are measured without error.

Practically, however, predictors are often measured with error. This has a profound (but predictable) effect on the estimates of relationships among variables – the so-called “error in variables” problem.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Error in predictor variables. (read)

Error in measuring the predictors is often ignored. In this column, we discuss when ignoring this error is harmless and when it can lead to large bias that can leads us to miss important effects.

Altman, N. & Krzywinski, M. (2024) Points of significance: Error in predictor variables. Nat. Methods 20.

Background reading

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple linear regression. Nat. Methods 12:999–1000.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of significance: Logistic regression. Nat. Methods 13:541–542 (2016).

Das, K., Krzywinski, M. & Altman, N. (2019) Points of significance: Quantile regression. Nat. Methods 16:451–452.

Martin Krzywinski | contact | Canada's Michael Smith Genome Sciences CentreBC Cancer Research CenterBC CancerPHSA
Google whack “vicissitudinal corporealization”
{ }