937 research outputs found

    Communicative Action and Citizen Journalism: A Case Study of \u3cem\u3eOhmyNews\u3c/em\u3e in South Korea

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    Drawing on Habermas’s theory of communicative action, this case study of OhmyNews in South Korea examines how citizen journalism operates in a broad organizational and social context. Through in-depth interviews with professional and citizen journalists, the study reveals that citizen journalism can be well understood at the intersection between the lifeworld and systems. Specifically, the study finds a coexistence mechanism by which citizen journalism competes, collaborates, coordinates, and compromises with professional journalism through communicative action, such as mutual understanding, reason-based discussion, and consensus building

    Coulomb Drag of Massless Fermions in Graphene

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    Using a novel structure, consisting of two, independently contacted graphene single layers separated by an ultra-thin dielectric, we experimentally measure the Coulomb drag of massless fermions in graphene. At temperatures higher than 50 K, the Coulomb drag follows a temperature and carrier density dependence consistent with the Fermi liquid regime. As the temperature is reduced, the Coulomb drag exhibits giant fluctuations with an increasing amplitude, thanks to the interplay between coherent transport in the graphene layer and interaction between the two layers.Comment: 5 pages, 5 figure

    Modeling the adoption and use of social media by nonprofit organizations

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    This study examines what drives organizational adoption and use of social media through a model built around four key factors - strategy, capacity, governance, and environment. Using Twitter, Facebook, and other data on 100 large US nonprofit organizations, the model is employed to examine the determinants of three key facets of social media utilization: 1) adoption, 2) frequency of use, and 3) dialogue. We find that organizational strategies, capacities, governance features, and external pressures all play a part in these social media adoption and utilization outcomes. Through its integrated, multi-disciplinary theoretical perspective, this study thus helps foster understanding of which types of organizations are able and willing to adopt and juggle multiple social media accounts, to use those accounts to communicate more frequently with their external publics, and to build relationships with those publics through the sending of dialogic messages.Comment: Seungahn Nah and Gregory D. Saxton. (in press). Modeling the adoption and use of social media by nonprofit organizations. New Media & Society, forthcomin

    U.S. Newspaper Editors’ Ratings of Social Media as Influential News Sources

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    Social media, as one key platform for citizen journalism, are becoming a useful news-gathering tool for journalists. Based on data from a nationwide probability sample of newspaper editors in the United States, this study investigates the extent to which newspaper editors consider social media an influential news source. Results show that variations in editors’ ratings of social media as a news source were related to multiple levels of influence, including professional journalistic experience, organization size, community structural pluralism, and citizen journalism credibility. Implications are discussed for the roles of social media in news production

    Structure and genetic diversity in wild and cultivated populations of Zapote mamey (Pouteria sapota, Sapotaceae) from southeastern Mexico: its putative domestication center

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    Tropical fruit trees are an important component of the human diet; however, little is known about their genetic diversity levels. Zapote mamey (Pouteria sapota) is a tree native to southeastern Mexico and Central America, and Mexico is the leading producer in the world. Studies of the genetic diversity of Zapote mamey have been based on cultivated materials using morphological and biochemical characterization or dominant molecular markers. To gain a deeper understanding about the conservation status of Zapote mamey in its center of origin and domestication, we collected 188 individuals from eight wild and five cultivated populations in southeastern Mexico and characterized them using eight microsatellite loci. STRUCTURE, 3D-PCoA, and neighbor-joining analyses showed three groups in the wild gene pool and one group in the cultivated gene pool. FST values were significant between wild and cultivated gene pools, among the four groups observed and among the 13 populations collected (0.13, 0.25, and 0.36, respectively). Overall, we found low levels of genetic diversity (A = 2.77, HO = 0.29, HE = 0.39), permutation tests did not show significant differences between wild and cultivated gene pools. The Garza–Williamson index showed low values in both gene pools (wild = 0.16, cultivated = 0.11) and the Bottleneck program indicated a decrease in genetic diversity in both gene pools (wild, P = 0.027; cultivated, P = 0.054); both analyses suggest a potential genetic bottleneck within this species. This study can help to generate adequate sampling techniques and to develop effective management strategies for Zapote mamey of southeastern Mexico

    Identifying Game Elements Suitable for MOOCs

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    Massive Online Open Courses (MOOCs) have increasingly become objects of research interest and studies in recent years. While MOOCs could be a means to address massive audiences, they suffer from high drop-out rates and low user engagement. Gamification is known as the application of game design elements in non-gaming scenarios to solve problems or to influence a user’s behaviour change. By applying gamification to MOOCs, we aim to enhance users’ engagement and goal achievement within a MOOC environment. To define our gamification strategy, we asked 42 experts in the fields of game design, learning science and technology-enhanced learning to rate 21 selected game design patterns according to their suitability within a MOOC environment application. The data collected allowed us to identify a set of nine game design patterns as promising candidates to be tested in MOOC environment

    AMoDSim: An Efficient and Modular Simulation Framework for Autonomous Mobility on Demand

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    Urban transportation of next decade is expected to be disrupted by Autonomous Mobility on Demand (AMoD): AMoD providers will collect ride requests from users and will dispatch a fleet of autonomous vehicles to satisfy requests in the most efficient way. Differently from current ride sharing systems, in which driver behavior has a clear impact on the system, AMoD systems will be exclusively determined by the dispatching logic. As a consequence, a recent interest in the Operations Research and Computer Science communities has focused on this control logic. The new propositions and methodologies are generally evaluated via simulation. Unfortunately, there is no simulation platform that has emerged as reference, with the consequence that each author uses her own custom-made simulator, applicable only in her specific study, with no aim of generalization and without public release. This slows down the progress in the area as researchers cannot build on each other's work and cannot share, reproduce and verify the results. The goal of this paper is to present AMoDSim, an open-source simulation platform aimed to fill this gap and accelerate research in future ride sharing systems

    Structure and genetic diversity in wild and cultivated populations of Zapote mamey (Pouteria sapota, Sapotaceae) from southeastern Mexico: its putative domestication center

    Get PDF
    Tropical fruit trees are an important component of the human diet; however, little is known about their genetic diversity levels. Zapote mamey (Pouteria sapota) is a tree native to southeastern Mexico and Central America, and Mexico is the leading producer in the world. Studies of the genetic diversity of Zapote mamey have been based on cultivated materials using morphological and biochemical characterization or dominant molecular markers. To gain a deeper understanding about the conservation status of Zapote mamey in its center of origin and domestication, we collected 188 individuals from eight wild and five cultivated populations in southeastern Mexico and characterized them using eight microsatellite loci. STRUCTURE, 3D-PCoA, and neighbor-joining analyses showed three groups in the wild gene pool and one group in the cultivated gene pool. FST values were significant between wild and cultivated gene pools, among the four groups observed and among the 13 populations collected (0.13, 0.25, and 0.36, respectively). Overall, we found low levels of genetic diversity (A = 2.77, HO = 0.29, HE = 0.39), permutation tests did not show significant differences between wild and cultivated gene pools. The Garza–Williamson index showed low values in both gene pools (wild = 0.16, cultivated = 0.11) and the Bottleneck program indicated a decrease in genetic diversity in both gene pools (wild, P = 0.027; cultivated, P = 0.054); both analyses suggest a potential genetic bottleneck within this species. This study can help to generate adequate sampling techniques and to develop effective management strategies for Zapote mamey of southeastern Mexico
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