"You don't see radio changing gradually and suddenly become radar. #Darwin's theory doesn't work for #technology, and we have to make a new observation."

- W Brian Arthur at SFI today

#evolution #innovation #invention

November is here, and that means a massive shift is coming. And by "massive" I am of course referring to the redefinition of the kilogram unit of mass that the world has been building up to for more than 100 years. Let me explain:

1/ I've had an unhealthy fascination with metrology (the study of measurement) ever since my 2nd year as a physics major when I took a class devoted to duplicating historic physics experiments, so please indulge me for going into heavy detail (get it?) about the kilogram.

2/ So what actually *defines* a unit of measurement? If you're American, you probably know a mile is 5280 feet and a foot is 12 inches and an inch is 2.54 centimeters etc. But where does this chain of definitions end? Is it turtles all the way down?

3/ It's actually not! For all units (even the imperial units used in America) the answers all end with the Système International (SI) unit definitions established and maintained for over 100 years by the Bureau International des Poids et Mesures (BIMP) in France.

4/ At the base of this tower are the SI base units. Just 7 SI base units define every other unit in existence. They are:

Kilogram, kg (mass)
Meter, m (distance)
Second, s (time)
Kelvin, K (temp)
Ampere, A (electric current)
Candela, cd (luminous intensity)
Mole, mol (quantity)

Did we get dietary saturated fats all wrong? The #HADLmodel provides a new understanding and an opportunity to get it right. THREAD👇👇👇
@simondankel @kariannesve

Increased dietary saturated fatty acids lead to increased cholesterol in lipoproteins, but we don’t know why. Enter the #HADLmodel, which explains changes in lipoprotein cholesterol as adaptive homeostatic adjustments that ensure optimal cell membrane fluidity and cell function.

We propose that circulating lipoproteins enable appropriate redistribution of cholesterol molecules between specific cells and tissues, to accomodate changes in dietary fatty acid supply, due to our omnivore nature and variable intake of fatty acids. #HADLmodel

Our #HADLmodel implies that circulating levels of LDL change for protective, not for pathological reasons; an SFA-induced raise in LDL cholesterol in healthy individuals is a normal response, while a lack of this needed response may reflect a deeper pathology in lipid handling.

Circulating lipoproteins may change for pathological reasons, when regulatory mechanisms become disrupted by pathogenic processes related e.g. to inflammatory processes. Diverging lipoprotein responses in healthy versus metabolically unhealthy individuals support this view.

11 BIG IDEAS OF PHYSICS

via @BlasMoros of @LTCWRK

(Thread 👇)

1. Galilean Relativity

We can never fully grasp, define, or understand a system we are part of.

“Distance provides perspective” and wisdom in life is often about perspective.

2. The Laws of Thermodynamics

The study of the large-scale behavior of systems exchanging work and heat with connected systems or their environment.

- The Transitive Law

- The Law of Conservation

- The “Contrast Advantage” Law

- The “Absolute Zero” Law

3. Newton’s Laws of Motion

Describe how objects in the world move and react to forces.

- The Inertia Law: An object at rest, stays at rest

- Force = Mass * Acceleration (F = ma)

- The Law of Reciprocity: For every action there is an equal and opposite reaction

4. Complexity

A complex system exhibits emergent behavior due to the collective interaction of many individual agents according to simple rules.

Complex systems are sensitive to original conditions, influenced by feedback loops, and buffeted by random outside variables.

Wonder why your Ph.D./Master's application is being rejected?

Here are some insider reasons (from a committee member) that result in such "Love Letters" 👇

- A Short Thread

1) First, you should know that sometimes, an independent reviewer is required (especially in the US) to review applications even after PIs must have selected their candidates. So, even if any bias slips through the PI, the independent reviewer will pick it up.

2) Having said this, there are three major issues that application reviewers/committees often find with your application. These three components make your applications almost challenging to assess.

3) NUMBER ONE - Incomplete Applications

This occurs when you do not upload the requested documents needed to evaluate your file. Think of a candidate that did not send a GRE score when the institution clearly requires it for admission.

4) NUMBER TWO - Error laden Essays

This is particularly interesting because based on reports from this resource person, it is not particularly about how little your experience is but how you communicate it error-free or at least extensively minimized. This gives headache!