Complex-Systems-Biology Approach to Plasticity and Robustness

Life systems generally consist of different levels with hierarchy, from molecules, cells, tissues, organisms, to ecosystem. States at each level change dynamically in time, while consistency between different levels is generally formed for a stable biosystem. Such consistency is shown to lead to general...

The Challenge of Obesity, and a Systems Approach to Solutions

Obesity has grown into a major global epidemic. Rates in the US have doubled since the 1980s, with more than two-thirds of adults now overweight (including more than one third who are obese). These trends are paralleled by rapid growth in childhood obesity, suggesting adult rates may continue to climb...

Genetic and Epigenetic Determinants of Chronic Lymphocytic Leukemia Evolution

Cancer plasticity poses one of the main challenges to achieving a cure, as the malignant cell population evolves and adapt in response to effective therapy. In this work, we applied a genomic scale tool to a large cohort of chronic lymphocytic leukemia patient samples in order to dissect the dynamics...

A Discourse on Decision Theory

In April 2010 I presented a seminar at SFI where I demonstrated that certain classic problems in economics can be resolved by methods that present an alternative to the dominant formalism of expected utilities in decision theory. Specifically, I noted that simple mathematical models of economic processes,...

Active Discovery of Network Roles for Predicting the Classes of Network Nodes

We consider a network in which we know how the nodes are connected, but we do not know the class labels of the nodes. We wish to identify the best subset of nodes to label, in order to most accurately predict the class labels of the rest of the nodes. In contrast to previous work, we do not assume that...

A Wild Solution for Climate Change

Our planet’s biology and its climate are inexorably coupled. Warmer and less predictable climates will continue to diminish the planet’s biodiversity. But biological systems can be part of a solution. Conservation biology pioneer Thomas Lovejoy will examine the present and possible future impacts of...

The Lexicon as a Dynamical System: The Drive to Keep Words Distinct and the Evolution of Phoneme Inventories

All human languages make use of small systems of signal categories, such as the sounds [p] and [b], in combination to compose meaningful lexical categories, such as the words "pat" and "bat." These perceptually contrastive, yet individually meaningless signal categories are often called phonemes. Over...

Self-Organized Criticality in Hamiltonian Spin Systems: Intriguingly Ordinary or Ordinarily Intriguing?

Self-organized criticality (SOC) refers to the tendency of dissipative systems to drive themselves into a scale-invariant critical state without any parameter tuning. These phenomena are of crucial importance because fractal objects displaying SOC are found everywhere, e.g., in earthquakes, the structure...

President's Welcome Message

The Omes That Matter: Teleome, Nature-ome, and Culture-ome

To understand biology and brain we must have, in addition to comprehensive mechanistic inventories like the genome and connectome, a comprehensive account of all the functions the biology implements – I call it the teleome, the suite of all teleologically-steeped "purposes" evolution instilled into the...

Turing's Cathedral: The Origins of the Digital Universe

The two most powerful technologies of the 20th century -- the nuclear bomb and the computer -- were developed in New Mexico at the same time and by the same group of young people. But while the history of the Manhattan Project has been well told, the origin of the computer is relatively unknown. In his...

Collective Phenomena, Collective Motion, and Collective Action in Ecological Systems

Gateways to Emergent Behavior in Science and Society

Landscapes and Beyond — Glasses, Proteins, and the Cell

Gateways to Emergent Behavior in Science and Society

Patterns of Synchrony: From Animal Gaits to Binocular Rivalry

Gateways to Emergent Behavior in Science and Society

Insects in Free Flight: Movement and Thoughts

Gateways to Emergent Behavior in Science and Society

The Emergence of Multicellularity

Gateways to Emergent Behavior in Science and Society

Modeling Computer Networks from Chips to the Internet

The Internet is, perhaps, the largest and most complex human artifact ever created, encompassing billions of technologies, organizations, and human users worldwide. It operates simultaneously on several interacting time scales -- from slow processes, such as hardware development, to data transport occurring...

The Complex Science of Cyberdefense: Computer Immunology

Threats are ubiquitous in complex systems: biology is rife with viruses, parasites, and bacteria; social networks abound with bullies; and international relations are stymied by rogue nations. In the second of three lectures, Stephanie Forrest proposes that understanding how complex systems generally...

Software Engineering: Evolving Computer Programs

Software -- used today for everything from shopping and banking to streaming movies -- shapes our daily experience. The software industry contributes billions of dollars annually to the U.S. economy and employs millions of Americans. Programmers like to think of software as the carefully crafted product...

An Exactly Solvable Model of Racial Segregation

In the 1960s and 70s Thomas C. Schelling, an economist then at Harvard, developed a simple agent-based simulation in which a mixed population of two races spontaneously breaks down into segregated enclaves, even though no member of the population seeks that outcome. Many variations of Schelling's model...