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Complexity Digest's Blog

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What we get wrong about technology

August 20, 2017 Comments (0)

Blade Runner (1982) is a magnificent film, but there’s something odd about it. The heroine, Rachael, seems to be a beautiful young woman. In reality, she’s a piece of technology — an organic robot designed by the Tyrell Corporation. She has a lifelike mind, imbued with memories extracted from a human being.  So sophisticated is Rachael that she is impossible to distinguish from a human without specialised equipment; she even believes herself to be human. Los Angeles...

Social influence on 5-year survival in a longitudinal chemotherapy ward co-presence network

August 19, 2017 Comments (0)

Chemotherapy is often administered in openly designed hospital wards, where the possibility of patient–patient social influence on health exists. Previous research found that social relationships influence cancer patient’s health; however, we have yet to understand social influence among patients receiving chemotherapy in the hospital. We investigate the influence of co-presence in a chemotherapy ward. We use data on 4,691 cancer patients undergoing chemotherapy in Oxfordshire,...

How your mind protects you against hallucinations

August 19, 2017 Comments (0)

More than 300 years ago, the philosopher René Descartes asked a disturbing question: If our senses can’t always be trusted, how can we separate illusion from reality? We’re able to do so, a new study suggests, because our brain keeps tabs on reality by constantly questioning its own past expectations and beliefs. Hallucinations occur when this internal fact-checking fails, a finding that could point toward better treatments for schizophrenia and other psychiatric disorders....

Corrupting cooperation and how anti-corruption strategies may backfire

August 17, 2017 Comments (0)

Understanding how humans sustain cooperation in large, anonymous societies remains a central question of both theoretical and practical importance. In the laboratory, experimental behavioural research using tools like public goods games suggests that cooperation can be sustained by institutional punishment—analogous to governments, police forces and other institutions that sanction free-riders on behalf of individuals in large societies1,2,3. In the real world, however, corruption can...

Spatiotemporal Network Markers of Individual Variability in the Human Functional Connectome

August 17, 2017 Comments (0)

Functional connectivity (FC) analysis has revealed stable and reproducible features of brain network organization, as well as their variations across individuals. Here, we localize network markers of individual variability in FC and track their dynamical expression across time. First, we determine the minimal set of network components required to identify individual subjects. Among specific resting-state networks, we find that the FC pattern of the frontoparietal network allows for the most...

Quantifying Retail Agglomeration using Diverse Spatial Data

August 17, 2017 Comments (0)

Newly available data on the spatial distribution of retail activities in cities makes it possible to build models formalized at the level of the single retailer. Current models tackle consumer location choices at an aggregate level and the opportunity new data offers for modeling at the retail unit level lacks an appropriate theoretical framework. The model we present here helps to address these issues. Based on random utility theory, we have built it around the idea of quantifying the role of...

The elegant law that governs us all

August 16, 2017 Comments (0)

  A dog owner weighs twice as much as her German shepherd. Does she eat twice as much? Does a big city need twice as many gas stations as one that is half its size? Our first instinct is to say yes. But, alas, we are wrong. On a per-gram basis, a human requires about 25% less food than her dog, and the larger city needs only 85% more gas stations. As Geoffrey West explains in Scale, the reason behind these intriguing phenomena is a universal law known as allometry—the finding that as...

Jury Rigging and Supply Network Design: Evolutionary “Tinkering” in the presence of Unknown‐Unknowns

August 16, 2017 Comments (0)

Nobel laureate François Jacob wrote often about evolution as “tinkering” in which parts and processes alone or together in cells and organisms were co-opted for new functional purposes. Such behavior remains unexamined concerning how adaptive systems succeed in biology, supply networks, the economy, and beyond. In the presence of Unknown-Unknown events (Unk-Unks) that have no prior occurrences and are evident only in their realizations, the design of supply networks must...

Mapping spreading dynamics: From time respecting shortest paths to bond percolation

August 15, 2017 Comments (0)

We propose a mapping of spreading dynamics to an ensemble of weighted networks, where edge weights represent propagation time delays. In this mapping, shortest paths in the weighted networks preserve the temporal causality of spreading. Our framework provides insights into the local and global spreading dynamics, enables efficient source detection, and helps to improve strategies for time-critical vaccination. Finally, we establish the connection of our mapping to bond percolation theory....

Logarithmic distributions prove that intrinsic learning is Hebbian.

August 14, 2017 Comments (0)

In this paper, we document lognormal distributions for spike rates, synaptic weights and intrinsic excitability (gain) for neurons in various brain areas, such as auditory or visual cortex, hippocampus, cerebellum, striatum, midbrain nuclei. We find a remarkable consistency of heavy-tailed, specifically lognormal, distributions for rates, weights and gains in all brain areas.The difference between strongly recurrent and feed-forward connectivity (cortex vs. striatum and cerebellum),...