## Profile

Heikki Arponen
Works at Freelancer
Attended University of Helsinki
8,008 followers|327,683 views

## Stream

### Heikki Arponen

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I just KNEW it!! (I've had to do my share of brainteasers too...)

Google also used to be famous for posing impossibly difficult and punishing brain teasers during interviews. Things like "If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes (assuming constant default probability)?"

Turns out those questions are"a complete waste of time," according to Bock. "They don’t predict anything. They serve primarily to make the interviewer feel smart."﻿
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### Heikki Arponen

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Hi! Any Theano users here? I just posted a question at StackOverflow about a problem I have when trying to use Theano for parameter estimation for a stochastic differential equation (I know, it's not ML but it should work).

http://stackoverflow.com/q/21945079/742616﻿
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### Heikki Arponen

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I want to learn about Deep Learning... I hope the book is finished soon!﻿
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### Heikki Arponen

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I have to say I'm usually a big skeptic, but this one seems like a very interesting and promising idea rigt off the bat: self organization by maximizing heat dissipation (or vice versa)!

I wonder if this could also be practically useful in e.g. microchip design to radically improve cooling... maybe this is the secret to our brain power?

props to  and of course to  ;)

Jeremy England has shown that when you have a system of atoms driven by an energy source (like visible light from the sun) and the system can disspate energy into a heat bath (say, by using some of the light to build water and CO₂ into sugar and emitting the rest as infra-red light) then the atoms will tend to arrange themselves in a way that maximizes their ability to diffuse the energy.

This is a key feature of life: everything that replicates has to consume useful energy in some form in order to assemble copies of itself, then dump the waste products.  It's possible that England's discovery explains how life began.

Ont he other hand, many scientists don't care whether it justifies abiogenesis or not: "He’s trying something radically different," said Mara Prentiss, a professor of physics at Harvard who is contemplating such an experiment after learning about England’s work.  "As an organizing lens, I think he has a fabulous idea. Right or wrong, it’s going to be very much worth the investigation."

His ideas remind me a lot of work by Harold Morowitz and his colleagues, who pointed out that all aerobic life uses the citric acid cycle for processing energy.  Early geologic processes probably would have run the citric cycle in reverse; he proposed that life arose as a way to dissipate the resulting free energy.
- http://tuvalu.santafe.edu/~desmith/PDF_talks/OOL_colloq_07.pdf
- http://goo.gl/PQ4fM6﻿
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### Heikki Arponen

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What the hell is wrong with modern physics today?!

I guess the citation and publication count of this "Tegmark" guy is going to go way up because of crap like this, so by today's standards he must be a very good scientist!

Our Mathematical Universe

"Tegmark’s career is a rather unusual story, mixing reputable science with an increasingly strong taste for grandiose nonsense. In this book he indulges his inner crank, describing in detail an uttery empty vision of the “ultimate nature of reality.” What’s perhaps most remarkable about the book is the respectful reception it seems to be getting..."﻿
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Yeah seems about right! Anyway, I'm sure some of Woit's blog readers will read and thrash it... which Teggy will of course brush aside as rantings of idiots who just don't understand him :P﻿

### Heikki Arponen

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Passed the Coursera Machine Learning course! It was fun to be back in "school" for a while! Got 100% score too ;) (well, it was an easy course)﻿
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Well of course "easy" is a relative concept... I have a lot of experience in math etc so that part was really easy. I guess this way the course reached a lot more people, which is always good. Overall it was a really good MOOC and I can recommend it to everyone interested in ML.﻿
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### Heikki Arponen

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What. The. F.... This might actually work, although I think at least a part of the Android charm is the Google ecosystem!﻿
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kaikista halvimmat mallit mä luulen, jos microsoft ei kolkuttelisi niin voisi nähdä niitä parempia kuin nexus5 kavaljeerit﻿
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### Heikki Arponen

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This needs to happen! G+ is no good (enough) if we can't do $\int dx e^{-x^2}$!!!

This is a campaign to get Google+ to support the LaTeX markup language for the purpose of posting to the stream.

2) Choose 'Send Feedback'
3) Type in something to the affect of "Please support LaTeX on Google+"
4) Drag the dialog box over your stream and click 'Submit'﻿
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Yes, Mathjax would make sense...﻿

### Heikki Arponen

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Very interesting and just a small part in the coming paradigm shift in medicine! (That's my "educated" guess at least)

The microbiome of the gut contains roughly 100 trillion microorganisms. This accounts for 50% of the weight of the contents of the lower digestive tract in humans.

Researchers from University of British Columbia have discovered a genetic mechanism that allows common gut bacterium, Bacteroides ovatus, to metabolize xyloglucan, a main component of dietary fiber from the cell walls of fruits and vegetables.

The findings reveal the specialized roles played by key members of our microbial community inside the human gut. This discovery could aid in the development of tailored microbiota transplants to improve intestinal health after antibiotic use or illness.

“While they are vital to our diet, the long chains of natural polymeric carbohydrates that make up dietary fibre are impossible for humans to digest without the aid of our resident bacteria,” says UBC professor Harry Brumer, with UBC’s Michael Smith Laboratories and Department of Chemistry, and senior author of the study.

“This newly discovered sequence of genes enables Bacteroides ovatus to chop up xyloglucan, a major type of dietary fibre found in many vegetables – from lettuce leaves to tomato fruits. B. ovatus and its complex system of enzymes provide a crucial part of our digestive toolkit.”

According to the researchers’ survey of public genome data from 250 adults, approximately 92% of the population harbors bacteria with a variant of the gene sequence.

“The next question is whether other groups in the consortium of gut bacteria work in concert with, or in competition with, Bacteroides ovatus to target these, and other, complex carbohydrates,” says Brumer.

Press Release: http://goo.gl/WqzbPC
This study was published in the journal Nature: http://goo.gl/sSFt6w
Image: vegetables, Wikimedia commons﻿
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We still haven't got out of the habit of wiping everything out without always having the need: http://goo.gl/RD7zgp﻿

### Heikki Arponen

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So my Windows 7 C drive is getting all full even though I keep installing new stuff onto my other huge drive with about 300GB left...

Hmm... I think I could clone the C drive to the bigger drive, but I was wondering if I should instead beat the machine with a sledge hammer, set it on fire and bury the remains... I'd lose some good hardware, but then again, I'd get rid of Windows... hmm...﻿
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IF there is such a thing ;)﻿
People
In his circles
758 people
Have him in circles
8,008 people
Work
Occupation
Mathematician -> quantitative researcher
Skills
Math, Python, quantitative finance, statistical arbitrage, stochastics, portfolio theory, regression analysis
Employment
• Freelancer
Independent researcher, 2011 - present
• University of Helsinki
Postdoc, 2009 - 2011
• University of Helsinki
Basic Information
Gender
Male
Relationship
In a relationship
Other names
Heka
Story
Tagline
Theoretical physicist and an aspiring quant.
Introduction
I'm a Finnish theoretical physicist with research experience and/or interests in turbulence, stochastic PDEs, nonlinear phenomena, QFT, differential geometry, gauge theories and gravity. I have PhD in math and Master's in theoretical physics, but I consider myself more theoretical physicist than a mathematician.
Bragging rights
My G+ vanity address: www.gplus.to/heka. Started using Google+ on july 16, 2011.
Education
• University of Helsinki
Math PhD, 2009
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