Month: October 2016

Dendrology: The community of trees

Trees are networkers. Far from the solitary splendour of the ancient old stager, it turns out that trees communicate with one another through their roots. Underground fungi — mycorrhizae associated with the root network — form a sort of subterranean internet that connects trees, passing messages and even nourishment between neighbours. Nor do trees passively tolerate the onslaught of insects on their tasty young leaves. Chemical signals carried on the breeze from infested trees cause forest fellows to crank up their own chemical armouries. It’s not a case of every tree for itself: the forest can behave as a single entity when it yields a great crop of acorns or beechnuts, or lies fallow for a year. Trees share a common response to weather and nourishment.

 

Dendrology: The community of trees
Richard Fortey
Nature 537, 306 (15 September 2016) doi:10.1038/537306a

Source: www.nature.com

The phylogenetic roots of human lethal violence

The percentage of human deaths caused by interpersonal violence reflects our membership of a particularly violent clade of mammals, although changes in socio-political organization have led to marked variations in this proportion.

 

The phylogenetic roots of human lethal violence
José María Gómez, Miguel Verdú, Adela González-Megías & Marcos Méndez
Nature 538, 233–237 (13 October 2016) doi:10.1038/nature19758

Source: www.nature.com

Symmetric States Requiring System Asymmetry

Spontaneous synchronization has long served as a paradigm for behavioral uniformity that can emerge from interactions in complex systems. When the interacting entities are identical and their coupling patterns are also identical, the complete synchronization of the entire network is the state inheriting the system symmetry. As in other systems subject to symmetry breaking, such symmetric states are not always stable. Here we report on the discovery of the converse of symmetry breaking–the scenario in which complete synchronization is not stable for identically-coupled identical oscillators but becomes stable when, and only when, the oscillator parameters are judiciously tuned to nonidentical values, thereby breaking the system symmetry to preserve the state symmetry. Aside from demonstrating that diversity can facilitate and even be required for uniformity and consensus, this suggests a mechanism for convergent forms of pattern formation in which initially asymmetric patterns evolve into symmetric ones.

 

Symmetric States Requiring System Asymmetry
Takashi Nishikawa, Adilson E. Motter

Source: arxiv.org

Compression and the origins of Zipf’s law for word frequencies

Here we sketch a new derivation of Zipf’s law for word frequencies based on optimal coding. The structure of the derivation is reminiscent of Mandelbrot’s random typing model but it has multiple advantages over random typing: (1) it starts from realistic cognitive pressures, (2) it does not require fine tuning of parameters, and (3) it sheds light on the origins of other statistical laws of language and thus can lead to a compact theory of linguistic laws. Our findings suggest that the recurrence of Zipf’s law in human languages could originate from pressure for easy and fast communication.

 

Compression and the origins of Zipf’s law for word frequencies
Ramon Ferrer-i-Cancho

Complexity

Source: onlinelibrary.wiley.com

An efficient system to fund science: from proposal review to peer-to-peer distributions

This paper presents a novel model of science funding that exploits the wisdom of the scientific crowd. Each researcher receives an equal, unconditional part of all available science funding on a yearly basis, but is required to individually donate to other scientists a given fraction of all they receive. Science funding thus moves from one scientist to the next in such a way that scientists who receive many donations must also redistribute the most. As the funding circulates through the scientific community it is mathematically expected to converge on a funding distribution favored by the entire scientific community. This is achieved without any proposal submissions or reviews. The model furthermore funds scientists instead of projects, reducing much of the overhead and bias of the present grant peer review system. Model validation using large-scale citation data and funding records over the past 20 years show that the proposed model could yield funding distributions that are similar to those of the NSF and NIH, and the model could potentially be more fair and more equitable. We discuss possible extensions of this approach as well as science policy implications.

 

An efficient system to fund science: from proposal review to peer-to-peer distributions

Johan Bollen, David Crandall, Damion Junk, Ying Ding, Katy Börner

Scientometrics (2016). doi:10.1007/s11192-016-2110-3

Source: link.springer.com