143 research outputs found
What Makes a Climate Change Denier Popular? Exploring Networked Social Influence in a Disinformation Spreader Group
Exploring the Network and Topic Stability in Climate Change Deniers’ Disinformation Network: A Longitudinal Study
A Global Perspective on Public Relations Professionalism: Mapping the Structure of Public Relations Associations’ International Networks
Associations play a powerful role in socializing practitioners. The presence of public relations associations across the world is one more step toward professionalization for the entire profession. This study examines the structure of global public relations professionalization manifested through the networks among international and national public relations professional associations. The findings of a cross-national, multilevel network analysis suggest that despite the overall dominance of international public relations associations, at the regional level, local centers have also emerged. In addition, European public relations associations have developed more relationships with other national, regional, and international associations than American-based professional associations.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Global civil society and a structural analysis of international NGOs's virtual networks
This dissertation sought to examine the virtual structure of global civil society via three theoretical frameworks: World System Theory, World Polity Theory and the current discussion of Network Society. Virtual interactions among 509 INGOs originating from 86 different countries and regions of the world were collected through data mining technology. Findings showed that, respectively, the three theories were significant at macro, meso and micro levels. Furthermore, this study showed that the collective consequence of technology use and the logics of network significantly affected the structure of the virtual networks of global civil society. Findings also revealed a trend of international inequality and Western dominance in the global civil arena. Theoretical and methodological implications were presented in the end
Optogenetic astrocyte activation modulates response selectivity of visual cortex neurons in vivo
Astrocytes play important roles in synaptic transmission and plasticity. Despite in vitro evidence, their causal contribution to cortical network activity and sensory information processing in vivo remains unresolved. Here we report that selective photostimulation of astrocytes with channelrhodopsin-2 in primary visual cortex enhances both excitatory and inhibitory synaptic transmission, through the activation of type 1a metabotropic glutamate receptors. Photostimulation of astrocytes in vivo increases the spontaneous firing of parvalbumin-positive (PV[superscript +]) inhibitory neurons, while excitatory and somatostatin-positive (SOM[superscript +]) neurons show either an increase or decrease in their activity. Moreover, PV[superscript +] neurons show increased baseline visual responses and reduced orientation selectivity to visual stimuli, whereas excitatory and SOM[superscript +] neurons show either increased or decreased baseline visual responses together with complementary changes in orientation selectivity. Therefore, astrocyte activation, through the dual control of excitatory and inhibitory drive, influences neuronal integrative features critical for sensory information processing.National Institutes of Health (U.S.)National Science Foundation (U.S.)Picower Institute for Learning and Memory (Innovation Fund)Simons FoundationMarie Curie International Outgoing Fellowship (FP7-253635)Consolider (CDS2010-00045)Ramon y Cajal Program (RYC-2012-12014
Preparation and Characterization of Mesoporous Zirconia Made by Using a Poly (methyl methacrylate) Template
Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol–gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, N2adsorption-desorption isotherms, and pore size distribution. The results indicate that the average pore size was found to be 3.7 nm
Political Public Relations in Advocacy: Building Online Influence and Social Capital
This article explores how political public relations activities support advocacy
efforts and allow organizations to communicate and partner with other organizations
and individuals to affect change. Our study examined the organizational relationships
that engaged in political advocacy to defeat the 2012 Stop Online Piracy Act (SOPA). We
argue that networked social capital provides a theoretical framework for broadening the
study of relationships from a dyadic approach to one that encompasses the multitude of
relationships necessary to bring about change. Structural hole theory was used to
identify influential organizations based on their network position. Two methods
including a hyperlink network analysis of organizational websites involved in the
Internet Blackout and a semantic network analysis of the SOPA legislation media
coverage revealed three findings: 1) diverse ties enhance political advocacy, 2) political
public relations can enhance network positions of organizations, and 3) evidence shows
that social media can be used strategically to capitalize on political activism
Dopamine Neuron-Specific Optogenetic Stimulation in Rhesus Macaques.
Optogenetic studies in mice have revealed new relationships between well-defined neurons and brain functions. However, there are currently no means to achieve the same cell-type specificity in monkeys, which possess an expanded behavioral repertoire and closer anatomical homology to humans. Here, we present a resource for cell-type-specific channelrhodopsin expression in Rhesus monkeys and apply this technique to modulate dopamine activity and monkey choice behavior. These data show that two viral vectors label dopamine neurons with greater than 95% specificity. Infected neurons were activated by light pulses, indicating functional expression. The addition of optical stimulation to reward outcomes promoted the learning of reward-predicting stimuli at the neuronal and behavioral level. Together, these results demonstrate the feasibility of effective and selective stimulation of dopamine neurons in non-human primates and a resource that could be applied to other cell types in the monkey brain.This work was supported by the Wellcome Trust (Principal Research Fellowship and Programme Grant 095495), European Research Council (ERC Advanced Grant 293549), and NIH Caltech Conte Center (P50MH094258)
A High-Light Sensitivity Optical Neural Silencer: Development and Application to Optogenetic Control of Non-Human Primate Cortex
Technologies for silencing the electrical activity of genetically targeted neurons in the brain are important for assessing the contribution of specific cell types and pathways toward behaviors and pathologies. Recently we found that archaerhodopsin-3 from Halorubrum sodomense (Arch), a light-driven outward proton pump, when genetically expressed in neurons, enables them to be powerfully, transiently, and repeatedly silenced in response to pulses of light. Because of the impressive characteristics of Arch, we explored the optogenetic utility of opsins with high sequence homology to Arch, from archaea of the Halorubrum genus. We found that the archaerhodopsin from Halorubrum strain TP009, which we named ArchT, could mediate photocurrents of similar maximum amplitude to those of Arch (∼900 pA in vitro), but with a >3-fold improvement in light sensitivity over Arch, most notably in the optogenetic range of 1–10 mW/mm2, equating to >2× increase in brain tissue volume addressed by a typical single optical fiber. Upon expression in mouse or rhesus macaque cortical neurons, ArchT expressed well on neuronal membranes, including excellent trafficking for long distances down neuronal axons. The high light sensitivity prompted us to explore ArchT use in the cortex of the rhesus macaque. Optical perturbation of ArchT-expressing neurons in the brain of an awake rhesus macaque resulted in a rapid and complete (∼100%) silencing of most recorded cells, with suppressed cells achieving a median firing rate of 0 spikes/s upon illumination. A small population of neurons showed increased firing rates at long latencies following the onset of light stimulation, suggesting the existence of a mechanism of network-level neural activity balancing. The powerful net suppression of activity suggests that ArchT silencing technology might be of great use not only in the causal analysis of neural circuits, but may have therapeutic applications
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