Month: December 2016

Global patterns of kelp forest change over the past half-century

Kelp forests support diverse and productive ecological communities throughout temperate and arctic regions worldwide, providing numerous ecosystem services to humans. Literature suggests that kelp forests are increasingly threatened by a variety of human impacts, including climate change, overfishing, and direct harvest. We provide the first globally comprehensive analysis of kelp forest change over the past 50 y, identifying a high degree of variation in the magnitude and direction of change across the geographic range of kelps. These results suggest region-specific responses to global change, with local drivers playing an important role in driving patterns of kelp abundance. Increased monitoring aimed at understanding regional kelp forest dynamics is likely to prove most effective for the adaptive management of these important ecosystems.

Source: www.pnas.org

2 Prof. Positions on Mathematical Modeling of Complex Biosystems, UC Riverside

Applications are invited for two 9-month, tenure-track or tenure positions at the Assistant or Associate levels beginning July 1, 2017, as a part of the cluster hiring initiative in Mathematical Modeling of Complex Biosystems at the University of California, Riverside (UCR). 

 

The University of California at Riverside (UCR) is implementing a major expansion of our faculty and investing in state-of-the-art research facilities to support their work. This expansion will build critical mass in 34 vital and emerging fields of scholarship, foster truly cross-disciplinary work, and further diversify the faculty at one of America’s most diverse research universities. We encourage applications from scholars committed to excellence and seeking to help define the research university for the next generation. For more information about our hiring initiative or to submit an application, please visit clusterhiring.ucr.edu or academicpersonnel.ucr.edu .

 

https://aprecruit.ucr.edu/apply/JPF00675
https://aprecruit.ucr.edu/apply/JPF00676

Source: aprecruit.ucr.edu

On Macrostates in Complex Multi-Scale Systems

A characteristic feature of complex systems is their deep structure, meaning that the definition of their states and observables depends on the level, or the scale, at which the system is considered. This scale dependence is reflected in the distinction of micro- and macro-states, referring to lower and higher levels of description. There are several conceptual and formal frameworks to address the relation between them. Here, we focus on an approach in which macrostates are contextually emergent from (rather than fully reducible to) microstates and can be constructed by contextual partitions of the space of microstates. We discuss criteria for the stability of such partitions, in particular under the microstate dynamics, and outline some examples. Finally, we address the question of how macrostates arising from stable partitions can be identified as relevant or meaningful.

 

On Macrostates in Complex Multi-Scale Systems
Harald Atmanspacher

Entropy 2016, 18(12), 426; doi: 10.3390/e18120426

Source: www.mdpi.com

Emergence: A Philosophical Account

Interest in emergence amongst philosophers and scientists has grown in recent years, yet the concept continues to be viewed with skepticism by many. In this book, Paul Humphreys argues that many of the problems arise from a long philosophical tradition that is overly committed to synchronic reduction and has been overly focused on problems in philosophy of mind. He develops a novel account of diachronic ontological emergence called transformational emergence, shows that it is free of the problems raised against synchronic accounts, shows that there are plausible examples of transformational emergence within physics and chemistry, and argues that the central ideas fit into a well-established historical tradition of emergence that includes John Stuart Mill, G.E. Moore, and C.D. Broad. The book also provides a comprehensive assessment of current theories of emergence and so can be used as a way into what is by now a very large literature on the topic. It places theories of emergence within a plausible classification, provides criteria for emergence, and argues that there is no single unifying account of emergence. Reevaluations of related topics in metaphysics are provided, including fundamentality, physicalism, holism, methodological individualism, and multiple realizability, among others. The relations between scientific and philosophical conceptions of emergence are assessed, with examples such as self-organization, ferromagnetism, cellular automata, and nonlinear systems being discussed. Although the book is written for professional philosophers, simple and intuitively accessible examples are used to illustrate the new concepts.

https://global.oup.com/academic/product/emergence-9780190620325?q=Humphreys&lang=en&cc=us#

Social status alters immune regulation and response to infection in macaques

Rhesus macaques experience variable levels of stress on the basis of their position in the social hierarchy. To examine how stress affects immune function, Snyder-Mackler et al. manipulated the social status of individual macaques (see the Perspective by Sapolsky). Social status influenced the immune system at multiple levels, from immune cell numbers to gene expression, and altered signaling pathways in a model of response to infection. Macaques possess a plastic and adaptive immune response wherein social subordination promotes antibacterial responses, whereas high social status promotes antiviral responses.

Source: science.sciencemag.org