Showing 1171 - 1180 of 2039 Items
The power of context in networks: Ideal point models with social interactions
Date: 2019-01-01
Creator: Mohammad T. Irfan
Tucker Gordon
Access: Open access
- Game theory has been widely used for modeling strategic behaviors in networked multiagent systems. However, the context within which these strategic behaviors take place has received limited attention. We present a model of strategic behavior in networks that incorporates the behavioral context, focusing on the contextual aspects of congressional voting. One salient predictive model in political science is the ideal point model, which assigns each senator and each bill a number on the real line of political spectrum. We extend the classical ideal point model with network-structured interactions among senators. In contrast to the ideal point model's prediction of individual voting behavior, we predict joint voting behaviors in a game-theoretic fashion. The consideration of context allows our model to outperform previous models that solely focus on the networked interactions with no contextual parameters. We focus on two fundamental problems: learning the model using real-world data and computing stable outcomes of the model with a view to predicting joint voting behaviors and identifying most influential senators. We demonstrate the effectiveness of our model through experiments using data from the 114th U.S. Congress.
Virtual Communities Don’t Exist: Avoiding Digital Dualism in Studying Collaboration
Creator: PJ Rey
Nathan Jurgenson
Access: Open access
- Effective collaboration in communities requires information sharing. Though digital media may have certain affordances that encourage us to communicate differently than in the past, the communities these media facilitate are no less real than communities bound together by voice or text. In this paper, we argue that idea of “virtual communities” is misleading. Communities and collaboration occur not in some virtual world or a new, cyber, space, but instead they are part of one reality influenced simultaneously by materiality and the various flows of information—digital included. In light of this argument, we implore researchers to take serious the influence of digitality, and, specific to this conference, those looking primarily at digitality to take seriously the materiality, bodies, history, and politics not separate from but deeply interpenetrating the digital. The changes in community organization brought about by digital media should not be thought of or called “virtual” (e.g., “virtual teams” as opposed to real ones), but instead part of one augmented community
Human protein Sam68 relocalization and interaction with poliovirus RNA polymerase in infected cells
Date: 1996-03-19
Creator: A. E. Mcbride
A. Schlegel
K. Kirkegaard
Access: Open access
- A HeLa cDNA expression library was screened for human polypeptides that interacted with the poliovirus RNA-dependent RNA polymerase, 3D, using the two-hybrid system in the yeast Saccharomyces cerevisiae. Sam68 (Src- associated in mitosis, 68 kDa) emerged as the human cDNA that, when fused to a transcriptional activation domain, gave the strongest 3D interaction signal with a LexA-3D hybrid protein. 3D polymerase and Sam68 coimmunoprecipitated from infected human cell lysates with antibodies that recognized either protein. Upon poliovirus infection. Sam68 relocalized from the nucleus to the cytoplasm, where poliovirus replication occurs. Sam68 was isolated from infected cell lysates with an antibody that recognizes poliovirus protein 2C, suggesting that it is found on poliovirus-induced membranes upon which viral RNA synthesis occurs. These data, in combination with the known RNA- and protein-binding properties of Sam68, make Sam68 a strong candidate for a host protein with a functional role in poliovirus replication.
The “New” Prosumer: Collaboration on the Digital and Material “New Means of Prosumption”
Creator: George Ritzer
Access: Open access
- Many of “cyber-utopians” have lauded the Internet, especially social networking sites, for a variety of reasons, including making possible a dramatic and revolutionary increase in social collaboration (Benkler, 2007; Tapscott and Williams, 2006). The goal of this essay is to examine- and, at least in part, debunk- this claim from a new and unique sociological perspective- the relationship between collaboration and the “new means of prosumption”. Such an examination is suggested by the fact that collaboration is, by definition, a form of prosumption. That is, it involves one or more parties “producing” and other(s) “consuming” something of mutual interest and importance. However, the collaborative process, like prosumption more generally, is not as separable as all that. In fact, collaboration is a dialectical process in which those involved are continually changing their positions on the prosumption continuum (see below), sometimes they are more
Xanthophyll cycle activity in two prominent arctic shrub species
Date: 2017-01-01
Creator: T.S. Magney
B.A. Logan
J.S. Reblin
N.T. Boelman
J.U.H., Eitel
H.E. Greaves
K.L. Griffin
C.M. Prager
L.A. Vierling
Access: Open access
Locating noctiluca miliaris in the arabian sea: An optical proxy approach
Date: 2014-01-01
Creator: Patricia S. Thibodeau
Collin S. Roesler
Susan L. Drapeau
S. G. Prabhu Matondkar
Joaquim I., Goes
P. Jeremy Werdell
Access: Open access
- Coincident with shifting monsoon weather patterns over India, the phytoplankter Noctiluca miliaris has recently been observed to be dominating phytoplankton blooms in the northeastern Arabian Sea during the winter monsoons. Identifying the exact environmental and/or ecological conditions that favor this species has been hampered by the lack of concurrent environmental and biological observations on time and space scales relevant to ecologic and physiologic processes. We present a bio-optical proxy for N. miliaris measured on highly resolved depth scales coincident with hydrographic observations with the goal to identify conducive hydrographic conditions for the bloom. The proxy is derived from multichannel excitation chlorophyll a fluorescence and is validated with microscopy, pigment composition, and spectral absorption. Phytoplankton populations dominated by either diatoms or other dinoflagellates were additionally discerned. N. miliaris populations in full bloom were identified offshore in low-nutrient and low–N:P ratio surface waters within a narrow temperature and salinity range. These populations transitioned to high-biomass diatom-dominated coastal upwelling populations. A week later, the N. miliaris blooms were observed in declining phase, transitioning to very-low-biomass populations of non–N. miliaris dinoflagellates. There were no clear hydrographic conditions uniquely associated with the N. miliaris populations, although N. miliaris was not found in the upwelling or extremely oligotrophic waters. Taxonomic transitions were not discernible in the spatial structure of the bloom as identified by the ocean color Chl imagery, indicating that in situ observations may be necessary to resolve community structure, particularly for populations below the surface.
Measuring Creative Performance of Teams Through Dynamic Semantic Social Network Analysis
Creator: Peter Gloor
Access: Open access
- In this project we compare communication structure and content exchanged by members of creative, interdisciplinary teams of medical researchers, physicians, patients and caretakers with their creative output. We find that longitudinal social networking patterns and word usage predict creative performance. We collected the e-mail archives of 60 members of a community of researchers working on 12 projects improving various aspects of the daily lives of patients of Crohn’s disease. Our results indicate that more creative projects show a decrease in group density, while more actors are involved, and more emails are exchanged, suggesting that a more successful project attracts more attention from many different people. We also found that members of more creative projects use more emotional language, which gets more focused over time.
Contingent planning under uncertainty via stochastic satisfiability
Date: 2003-07-01
Creator: Stephen M. Majercik
Michael L. Littman
Access: Open access
- We describe a new planning technique that efficiently solves probabilistic propositional contingent planning problems by converting them into instances of stochastic satisfiability (SSAT) and solving these problems instead. We make fundamental contributions in two areas: the solution of SSAT problems and the solution of stochastic planning problems. This is the first work extending the planning-as-satisfiability paradigm to stochastic domains. Our planner, ZANDER, can solve arbitrary, goal-oriented, finite-horizon partially observable Markov decision processes (POMDPs). An empirical study comparing ZANDER to seven other leading planners shows that its performance is competitive on a range of problems. © 2003 Elsevier Science B.V. All rights reserved.