757 research outputs found
Urban Foraging and the Relational Ecologies of Belonging
Through a discussion of urban foraging in Seattle, Washington, USA, we examine how people\u27s plant and mushroom harvesting practices in cities are linked to relationships with species, spaces, and ecologies. Bringing a relational approach to political ecology, we discuss the ways that these particular nature–society relationships are formed, legitimated, and mobilized in discursive and material ways in urban ecosystems. Engaging closely with and as foragers, we develop an ethnographically grounded ‘relational ecologies of belonging’ framework to conceptualize and examine three constituent themes: cultural belonging and identity, belonging and place, and belonging and more-than-human agency. Through this case study, we show the complex ways that urban foraging is underpinned by interconnected and multiple notions of identity, place, mobility, and agency for both humans and more-than-human interlocutors. The focus on relational ecologies of belonging illuminates important challenges for environmental management and public space planning in socioecologically diverse areas. Ultimately, these challenges reflect negotiated visions about how we organize ourselves and live together in cosmopolitan spaces such as cities
Information mobility in complex networks
The concept of information mobility in complex networks is introduced on the basis of a stochastic process taking place in the network. The transition matrix for this process represents the probability that the information arising at a given node is transferred to a target one. We use the fractional powers of this transition matrix to investigate the stochastic process at fractional time intervals. The mobility coefficient is then introduced on the basis of the trace of these fractional powers of the stochastic matrix. The fractional time at which a network diffuses 50% of the information contained in its nodes (1/ k50 ) is also introduced. We then show that the scale-free random networks display better spread of information than the non scale-free ones. We study 38 real-world networks and analyze their performance in spreading information from their nodes. We find that some real-world networks perform even better than the scale-free networks with the same average degree and we point out some of the structural parameters that make this possible
Communicability in complex networks
Many topological and dynamical properties of complex networks are defined by
assuming that most of the transport on the network flows along the shortest
paths. However, there are different scenarios in which non-shortest paths are
used to reach the network destination. Thus the consideration of the shortest
paths only does not account for the global communicability of a complex
network. Here we propose a new measure of the communicability of a complex
network, which is a broad generalization of the concept of the shortest path.
According to the new measure, most of real-world networks display the largest
communicability between the most connected (popular) nodes of the network
(assortative communicability). There are also several networks with the
disassortative communicability, where the most "popular" nodes communicate very
poorly to each other. Using this information we classify a diverse set of
real-world complex systems into a small number of universality classes based on
their structure-dynamic correlation. In addition, the new communicability
measure is able to distinguish finer structures of networks, such as
communities into which a network is divided. A community is unambiguously
defined here as a set of nodes displaying larger communicability among them
than to the rest of nodes in the network.Comment: 20 pages, 5 figure
Fusion cross section for the system <SUP>6</SUP>Li+<SUP>28</SUP>Si at E~36 MeV
The fusion cross section for the system 6Li+28Si has been measured at E~36 MeV. Combining this with the data available at lower energies, the nucleus-nucleus real potentials have been determined for a range of interaction distances
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High Energy Gamma Rays from p+X, X=Cu, Ag, Au at 34 MeV
In this paper we present results from the measurement of the gamma ray yield in the reaction of 34-MeV protons on Cu, Ag and Au. The protons were produced by the University of Washington superconducting linac. The gamma rays were measured using a large NaI and two large BaF{sub 2} detectors. Angular distributions were obtained for each of the three targets. Data for the Cu and Ag target were taken at six lab angles between 35 and 135 degrees, while data were taken at eight lab angles between 35 and 135 degrees for the Au target. The data were compared to several models. These included Hauser-Feshbach and direct-semidirect (DSD) calculations. We also compared the measurements to proton-nucleus bremsstrahlung calculations. The bremsstrahlung calculations greatly underpredicted the cross section and produced an angular distribution which was too flat. The Hauser-Feshbach calculations reproduced the yield of the softer portion of the spectrum reasonably well for all three targets. The DSD calculations reproduced the yield and angular distributions quite well for energies above about 20 MeV. However, the yields were underpredicted in the 15-18 MeV region, which suggests that multistep mechanisms may be needed for this target
Finding a Disappearing Nontimber Forest Resource: Using Grounded Visualization to Explore Urbanization Impacts on Sweetgrass Basketmaking in Greater Mt. Pleasant, South Carolina
Despite growing interest in urbanization and its social and ecological impacts on formerly rural areas, empirical research remains limited. Extant studies largely focus either on issues of social exclusion and enclosure or ecological change. This article uses the case of sweetgrass basketmaking in Mt. Pleasant, South Carolina, to explore the implications of urbanization, including gentrification, for the distribution and accessibility of sweetgrass, an economically important nontimber forest product (NTFP) for historically African American communities, in this rapidly growing area. We explore the usefulness of grounded visualization for research efforts that are examining the existence of fringe ecologies associated with NTFP. Our findings highlight the importance of integrated qualitative and quantitative analyses for revealing the complex social and ecological changes that accompany both urbanization and rural gentrification
In-situ Optimized Substrate Witness Plates: Ground Truth for Key Processes on the Moon and Other Planets
Future exploration efforts of the Moon, Mars and other bodies are poised to
focus heavily on persistent and sustainable survey and research efforts,
especially given the recent interest in a long-term sustainable human presence
at the Moon. Key to these efforts is understanding a number of important
processes on the lunar surface for both scientific and operational purposes. We
discuss the potential value of in-situ artificial substrate witness plates,
powerful tools that can supplement familiar remote sensing and sample
acquisition techniques and provide a sustainable way of monitoring processes in
key locations on planetary surfaces while maintaining a low environmental
footprint. These tools, which we call Biscuits, can use customized materials as
wide ranging as zircon-based spray coatings to metals potentially usable for
surface structures, to target specific processes/questions as part of a small,
passive witness plate that can be flexibly placed with respect to location and
total time duration. We examine and discuss unique case studies to show how
processes such as water presence/transport, presence and contamination of
biologically relevant molecules, solar activity related effects, and other
processes can be measured using Biscuits. Biscuits can yield key location
sensitive, time integrated measurements on these processes to inform scientific
understanding of the Moon and enable operational goals in lunar exploration.
While we specifically demonstrate this on a simulated traverse and for selected
examples, we stress all groups interested in planetary surfaces should consider
these adaptable, low footprint and highly informative tools for future
exploration.Comment: Accepted to Earth and Space Science, Will be updated upon publicatio
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