On analytical statistics and critical realism — LARS P. SYLL

I re-blog here today this nice pos from a fellow WordPress economist Blogger. And Nature& Science is also posting on Probability&Statistics, Mathematics topics.

 

In this paper we began by describing the position of those critical realists who are sceptical about multi-variate statistics … Some underlying assumptions of this sceptical argument were shown to be false. Then a positive case in favour of using analytical statistics as part of a mixed-methods methodology was developed. An example of the interpretation […]

via On analytical statistics and critical realism — LARS P. SYLL

Early warning signals of regime shifts in coupled human–environment systems — Complexity Digest

In complex systems, a critical transition is a shift in a system’s dynamical regime from its current state to a strongly contrasting state as external conditions move beyond a tipping point. These transitions are often preceded by characteristic early warning signals such as increased system variability. However, early warning signals in complex, coupled human–environment systems (HESs) remain little studied. Here, we compare critical transitions and their early warning signals in a coupled HES model to an equivalent environment model uncoupled from the human system. We parameterize the HES model, using social and ecological data from old-growth forests in Oregon. We find that the coupled HES exhibits a richer variety of dynamics and regime shifts than the uncoupled environment system. Moreover, the early warning signals in the coupled HES can be ambiguous, heralding either an era of ecosystem conservationism or collapse of both forest ecosystems and conservationism. The presence of human feedback in the coupled HES can also mitigate the early warning signal, making it more difficult to detect the oncoming regime shift. We furthermore show how the coupled HES can be “doomed to criticality”: Strategic human interactions cause the system to remain perpetually in the vicinity of a collapse threshold, as humans become complacent when the resource seems protected but respond rapidly when it is under immediate threat. We conclude that the opportunities, benefits, and challenges of modeling regime shifts and early warning signals in coupled HESs merit further research. Source: www.pnas.org

via Early warning signals of regime shifts in coupled human–environment systems — Complexity Digest

More from Complexity Digest: Home | NetSci 2017

 

 

 

NetSci 2017 aims to bring together leading researchers and practitioners working in the emerging area of network science. The conference fosters interdisciplinary communication and collaboration in…

Source: Home | NetSci 2017

 

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A re-post from Complexity Digest – Dendrology: The community of trees

Dendrology: The community of trees

Source: Dendrology: The community of trees

On two kinds of ignorance

I think there are two kinds of ignorance: one which is positive and a kind motor force of the world of knowledge; and one negative with which so much of Humanity find herself imprisoned. The negative ignorance is also more widespread, and this may be the reason that when we hear, read or pronounce this word, the first reaction is one of negativity and disgust. This kind of ignorance is of course a very bad state of affairs, as it invariably pushes everyone to one corner of our Minds where is difficult to get out; and it always finds ways to perpetuate itself in a whirlpool of further ignorance upon ignorance and error, and each move is like a move in a deadly swamp… But let us not forget about that first motor force of knowledge: a kind of bliss ignorance that propels us to seek more and more layers of further knowledge, and where the whirlpool is a happy virtuous one.

Bayes vs. Keynes on probability and belief in economic theory

An alternative possibility is to accept the consequences of the apparent fact that the central prediction of the Bayesian model in its descriptive capacity, that people’s choices are or are &…

Source: Bayes vs. Keynes on probability and belief in economic theory

The Start of Time (Physics)

I repost today this wonderful take on the Physics of Time by a recent follower of Self-organized Science&Technology.

Scientific Babble

The 2 common ways that the world was believed to have been created was:

• The Big Bang Theory – Science
• Creation – Christianity

Today I am going to talk about a few different versions humans have on how the world was created. Before I get started I would just like to point out that there are many different versions we have about the beginning of time, some science based, some religious. Everyone has the right to believe in what they deem is correct and not to be judged on their views.

First up, ‘The Big Bang Theory’

Most astronomers believed that 13.8 billion ears ago, there was a HUGE explosion! At that time, the entire universe was inside a bubble that was thousands of times smaller than a pinhead. It was hotter and denser than anything we can comprehend. BANG!!! It instantaneously exploded. Time, space and matter all started with the Big Bang. In a fraction of…

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International Workshop on Nonlinearity, Nonequilibrium and Complexity: Questions and perspectives in Statistical Physics.

         The workshop is aimed at discussing a few chosen contemporary developments in statistical physics. Topics include problems in condensed matter and dynamical systems (pattern structures, granular matter, glass formation, turbulence, marginal chaos, etc.); and also current applications outside of traditional fields in physics (in biology, ecology, sociology, economy, seismology and other geophysical, astrophysical phenomena, complexity in urban developments, complexity in linguistics, literature and arts, etc.). There would be an examination of equilibrium and nonequilibrium theories, and of the current efforts in generalizing statistical mechanical structures and methods. We would like to emphasize that our aim is to make the meeting the occasion for a memorable scientific discussion that can be carried out comfortably in an intimate environment.

International Workshop on Nonlinearity, Nonequilibrium and Complexity: Questions and perspectives in Statistical Physics. This is an event in honor of Prof. Alberto Robledo’s 70th birthday.

Mexico City, Mexico

A New Mathematical Model for Memory – repost

Repost from the excellent site neurosciencenews.com:

Human memory is the result of different mental processes, such as learning, remembering and forgetting. However, these distinct processes cannot be observed directly. Researchers at the University of Basel now succeeded at describing them using computational models. The scientists were thus for the first time able to identify gene sets responsible for steering specific memory processes. Their results have been published in the current issue of the journal PNAS.

Thanks to our memory we are able to learn foreign languages, solve exams and remember beautiful moments from the past. To ensure optimal memory performance, several distinct cognitive processes have to cooperate. Information is first learned and then stored. Later, when we want to remember them, we depend on a properly functioning retrieval process.

If all these various memory processes are controlled by the same or by different genes and molecular mechanisms has so far been mostly unknown. One reason for this, is the fact that many of these processes are not amenable to direct measurement and have therefore remained inaccessible for science.

Researchers at the University of Basel succeeded at describing distinct memory processes, such as learning, remembering and forgetting using a computational model. Image credit: MCN University of Basel.

A Mathematical Model for Memory

Pedro Vieira at the Perimeter Institute

Today’s news are nice indeed for a Portuguese such as me with a persistent enthusiasm for Science, and Physics in particular. I must say that I didn’t know Pedro Vieira‘s work and career, but given his age and excellent achievements thus far, it isn’t difficult to predict a few more good surprises in the years to come.

Perimeter Faculty member Pedro Vieira

Pedro Vieira’s field of study – Mathematical Physics – was one of my favourites while in College, where my grades were the best ones. So despite the fact of not have been this successful in my Research pursuits, Pedro’s example is and always will be a source of inspiration and in a way a form  of forcing me to look back and reconsider my path in the enthusiasm for Physics and Science. It is always a good time to re-evaluate what we do in Life, what we stand for, what are our preferences and decisions, why things happen in a way and not otherwise. Pedro’s example has made this effect on me today.

It’s been a big year for Perimeter’s Pedro Vieira. He recently won a Sloan Fellowship. Early career researchers who win Sloan Fellowships are widely viewed as people to keep an eye on, and with good reason: 42 of them have gone on to win Nobel Prizes. Now, Vieira’s been awarded the 2015 Gribov Medal, which honours outstanding work in theoretical particle physics or field theory by a physicist who is under 35 years old. The prestigious award is given once every two years by the European Physical Society. In other words, Vieira – who is just 32 – has now won a top award for young physicists on two continents. “We are delighted to see Pedro so widely recognized,” says Perimeter Faculty ChairRobert Myers. “He has a rare combination of mathematical talent and physical intuition, and he is doing remarkable work.” The European Physical Society cited Vieira “for his groundbreaking contributions to the determination of the exact spectrum of anomalous dimensions of N=4 supersymmetric Yang Mills theory and scattering amplitudes, for any interaction strength.”

PERIMETER FACULTY MEMBER WINS MAJOR INTERNATIONAL PRIZE

Photo Source: Perimeter Institute’s website