Sunday, April 26, 2015

How Can I Go About Understanding the Math in Nassim Taleb's Technical Papers?

A great answer to this great question @ Quora:

Taleb uses fairly advanced math, especially Analysis, Probability and Statistics. So the first step would be to crack up a book on university-level analysis theory and building on that. Exercise are not dispensable, since that’s when you will internalize the concepts that you are presented. Merely reading about them is not enough, you have to handle them to really get a grasp on what they mean.

I would like to tell you that you can make do without studying things like linear algebra, which seem at first a bit distant from analysis, but unfortunately, they are absolutely crucial in understanding probability theory, so you’ll have to do that as well. Mathematics is a discipline in which you become knowledgeable by making yours a lot of intermediary concepts. It’s a fascinating journey, but there are no shortcuts. Good luck.

Quote of the Day

Every question is a cry to understand the world. There is no such thing as a dumb question.

-  Carl Sagan, The Demon-Haunted World: Science as a Candle in the Dark

Saturday, April 25, 2015

Wisdom Of The Week

In the 1990s, no academic could sell a message about lowered serotonin. There was no correlation between serotonin reuptake inhibiting potency and antidepressant efficacy. No one knew if SSRIs raised or lowered serotonin levels; they still don’t know. There was no evidence that treatment corrected anything.

The role of persuading people to restore their serotonin levels to “normal” fell to the newly obligatory patient representatives and patient groups. The lowered serotonin story took root in the public domain rather than in psychopharmacology. This public serotonin was like Freud’s notion of libido—vague, amorphous, and incapable of exploration—a piece of biobabble. If researchers used this language it was in the form of a symbol referring to some physiological abnormality that most still presume will be found to underpin melancholia—although not necessarily primary care “depression.”

The myth co-opted the complementary health market. Materials from this source routinely encourage people to eat foods or engage in activities that will enhance their serotonin levels and in so doing they confirm the validity of using an antidepressant. The myth co-opts psychologists and others, who for instance attempt to explain the evolutionary importance of depression in terms of the function of the serotonin system. Journals and publishers take books and articles expounding such theories because of a misconception that lowered serotonin levels in depression are an established fact, and in so doing they sell antidepressants.

Above all the myth co-opted doctors and patients. For doctors it provided an easy short hand for communication with patients. For patients, the idea of correcting an abnormality has a moral force that can be expected to overcome the scruples some might have had about taking a tranquilliser, especially when packaged in the appealing form that distress is not a weakness.

[---]

Serotonin is not irrelevant. Just as with noradrenaline, dopamine, and other neurotransmitters, we can expect it to vary among individuals and expect some correlation with temperament and personality.There were pointers to a dimensional role for serotonin from the 1970s onwards, with research correlating lowered serotonin metabolite levels with impulsivity leading to suicidality, aggression, and alcoholism.As with the eclipse of cortisol, this research strand also ran into the sand; SSRIs lower serotonin metabolite levels in at least some people, and they are particularly ineffective in patient groups characterised by impulsivity (those with borderline personality traits).

This history raises a question about the weight doctors and others put on biological and epidemiological plausibility. Does a plausible (but mythical) account of biology and treatment let everyone put aside clinical trial data that show no evidence of lives saved or restored function? Do clinical trial data marketed as evidence of effectiveness make it easier to adopt a mythical account of biology? There are no published studies on this topic.

These questions are important. In other areas of life the products we use, from computers to microwaves, improve year on year, but this is not the case for medicines, where this year’s treatments may achieve blockbuster sales despite being less effective and less safe than yesterday’s models. The emerging sciences of the brain offer enormous scope to deploy any amount of neurobabble.We need to understand the language we use. Until then, so long, and thanks for all the serotonin.


- Serotonin & Depression


Quote of the Day

Because vision appears so effortless, we are like fish challenged to understand water.

- David Eagleman, Incognito: The Secret Lives of the Brain

Friday, April 24, 2015

The Vital Question: Why is life the way it is?

 

A must read new book by Nick Lane - The Vital Question: Why is life the way it is? and a great review here

Living cells are powered by a totally unexpected process. The energy from food is used to pump protons across a membrane to build up an electrochemical gradient. This gradient drives the machinery of life, like water from a dam driving a turbine.

And Lane argues that life has been powered by proton gradients from the very beginning. Forget all those primordial soups or "warm ponds": only the natural proton gradients found in undersea alkaline hydrothermal vents could have provided the continuous flux of carbon and energy that life requires. These vents may be common on rocky planets so, if this reasoning is correct, simple cells should be too.

It's the next step that is tricky. To become more complex, cells need more membrane to provide more energy. But the larger the area of membrane, the harder it is to keep control of the proton gradient – and losing control means death. So cells stayed simple. "There is no innate or universal trajectory towards complex life," Lane writes.

Not, at least, until something extraordinary happened: one kind of simple cell somehow started living inside another. Eventually, the first cell turned into the self-contained energy-producing structures we call mitochondria. This Russian-doll arrangement meant cells could get more energy simply by making more mitochondria, allowing them to become much larger and more complex.

But learning to live together was far from easy. The first complex cells were forced to evolve features such as sexual reproduction and DNA wrapped up in a membrane to survive. In other words, the acquisition of mitochondria wasn't just necessary for cells to become complex, it shaped their entire nature – and it still does. Our lifespans are determined by our mitochondria, Lane argues, but not because they produce free radicals, as we once thought.

It sometimes seems that there are few big ideas in biology any more, that it's all about specialists crunching data. But this is a book of vast scope and ambition, brimming with bold and important ideas. I do hope some of them are wrong, because it's disappointing to think that alien life consists mostly of slime, or that it will be very difficult to extend our lifespans beyond about 120 years.

Quote of the Day

What's the use of a fine house if you haven't got a tolerable planet to put it on?

- Henry David Thoreau, Familiar Letters

Thursday, April 23, 2015

Quote of the Day

I have had my mother's wing of my genetic ancestry analyzed by the National Geographic tracing service and there it all is: the arrow moving northward from the African savannah, skirting the Mediterranean by way of the Levant, and passing through Eastern and Central Europe before crossing to the British Isles. And all of this knowable by an analysis of the cells on the inside of my mouth.

I almost prefer the more rambling and indirect and journalistic investigation, which seems somehow less… deterministic.


- Christopher Hitchens, Hitch-22: A Memoir


Wednesday, April 22, 2015

Quote of the Day

Putting things off is the biggest waste of life: it snatches away each day as it comes, and denies us the present by promising the future. The greatest obstacle to living is expectancy, which hangs upon tomorrow, and loses today. You are arranging what lies in Fortune's control, and abandoning what lies in yours. What are you looking at? To what goal are you straining? The whole future lies in uncertainty: live immediately.

- Seneca

Tuesday, April 21, 2015

Quote of the Day

To compose our character is our duty, not to compose books, and to win, not battles and provinces, but order and tranquility in our conduct. Our great and glorious masterpiece is to live appropriately. All other things, ruling, hoarding, building, are only little appendages and props, at most.

-  Michel de Montaigne

Monday, April 20, 2015

Quote of the Day

Those who think money can't buy happiness just don't know where to shop … People would be happier and healthier if they took more time off and spent it with their family and friends, yet America has long been heading in the opposite direction. People would be happier if they reduced their commuting time, even if it meant living in smaller houses, yet American trends are toward even larger houses and ever longer commutes. People would be happier and healthier if they took longer vacations even if that meant earning less, yet vacation times are shrinking in the United States, and in Europe as well. People would be happier, and in the long run and wealthier, if they bought basic functional appliances, automobiles, and wristwatches, and invested the money they saved for future consumption; yet, Americans and in particular spend almost everything they have – and sometimes more – on goods for present consumption, often paying a large premium for designer names and superfluous features.

- Jonathan Haidt, The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom