jueves, 14 de mayo de 2009

Selección del Complexity Digest - Mayo

The reductionist blind spot, Complexity

Abstract: Can there be higher level laws of nature even though everything is reducible to the fundamental laws of physics? The computer science notion of level of abstraction explains how there can be. The key relationship between elements on different levels of abstraction is not the is-composed-of relationship but the implements relationship. I take a scientific realist position with respect to (material) levels of abstraction and their instantiation as (material) entities. They exist as objective elements of nature. Reducing them away to lower order phenomena produces a reductionist blind spot and is bad science.

On irreducible description of complex systems, Complexity

Abstract: The aim of the article is to present the description of complex systems in terms of self-organization processes of prime integer relations and illustrate its main properties. Based on the integers and controlled by arithmetic only, the processes can characterize complex systems by information not requiring further simplification. This raises the possibility to develop an irreduc

ible theory of complex systems.

Climate change: Too much of a bad thing, Nature

Excerpt: There are various and confusing targets to limit

global warming due to emissions of greenhouse gases. Estimates based on the total slug of carbon emitted are possibly the most robust, and are worrisome.
See Also: The Climate Crunch online collection.

The worst-case scenario, Nature

Excerpt: In a 1,000 p.p.m. scenario, many unique or rare systems would probably be lost, including Arctic sea ice, mountain-top glaciers, most threatened and endangered species, coral-reef communities, and many high-latitude and high-altitude indigenous human cultures. People would be vulnerable in other ways too: Asian mega-delta cities would face rising sea levels and rapidly intensifying tropical cyclones, creating hundreds of millions of refugees; valuable infrastructure such as the London or New York underground systems could be damaged or lost; the elderly would be at risk from unprecedented heat waves; and children, who are especially vulnerable to malnutrition in poor areas, would face food shortages.

What's Bugging Plants?, Science

Excerpt: Plants, like other organisms, including animals, live immersed in a thriving community of microbes. The diversity of fungi, oomycetes, and bacteria with which plants interact brings both plague and benefit. The more we understand how plants tame, thwart, and succumb to their bugs, the more likely we will be able to extract new resources for antimicrobial treatments and manage agricultural challenges

  • Source: What's Bugging Plants?, Pamela J. Hines and Laura M. Zahn, DOI: 10.1126/science.324_741, Science Vol. 324. no. 5928, p. 741, 2009/05/08

Alexander von Humboldt and the General Physics of the Earth, Science

Excerpt: As scientists are celebrating the 200th anniversary of Charles Darwin's birth and the 150th anniversary of the publication of his On the Origin of Species, Darwin's ideas continue to shape and enrich the sciences. 6 May 2009 marks the 150th anniversary of the death of another 19th-century figure"Alexander von Humboldt"whose scientific legacy also flourishes in the 21st century. Humboldt helped create the intellectual world Darwin inhabited, and his writings inspired Darwin to embark on H.M.S. Beagle. More pertinent to our time, Humboldt established the foundation for the Earth system sciences: the integrated system of knowledge on which human society may depend in the face of global climate change.

No hay comentarios: