Rate theory for correlated processes: Double-jumps in adatom diffusion

We study the rate of activated motion over multiple barriers, in particular the correlated double-jump of an adatom diffusing on a missing-row reconstructed Platinum (110) surface. We develop a Transition Path Theory, showing that the activation energy is given by the minimum-energy trajectory which succeeds in the double-jump. We explicitly calculate this trajectory within an effective-medium molecular dynamics simulation. A cusp in the acceptance region leads to a sqrt{T} prefactor for the activated rate of double-jumps. Theory and numerical results agree

Subbarrel patterns in somatosensory cortical barrels can emerge from local dynamic instabilities

Complex spatial patterning, common in the brain as well as in other biological systems, can emerge as a result of dynamic interactions that occur locally within developing structures. In the rodent somatosensory cortex, groups of neurons called "barrels" correspond to individual whiskers on the contralateral face. Barrels themselves often contain subbarrels organized into one of a few characteristic patterns. Here we demonstrate that similar patterns can be simulated by means of local growth-promoting and growth-retarding interactions within the circular domains of single barrels. The model correctly predicts that larger barrels contain more spatially complex subbarrel patterns, suggesting that the development of barrels and of the patterns within them may be understood in terms of some relatively simple dynamic processes. We also simulate the full nonlinear equations to demonstrate the predictive value of our linear analysis. Finally, we show that the pattern formation is robust with respect to the geometry of the barrel by simulating patterns on a realistically shaped barrel domain. This work shows how simple pattern forming mechanisms can explain neural wiring both qualitatively and quantitatively even in complex and irregular domains. © 2009 Ermentrout et al

Being in front is good—but where is in front? Preferences for spatial referencing affect evaluation

Speakers of English frequently associate location in space with valence, as in moving up and down the “social ladder.” If such an association also holds for the sagittal axis, an object “in front of” another object would be evaluated more positively than the one “behind.” Yet how people conceptualize relative locations depends on which frame of reference (FoR) they adopt—and hence on cross‐linguistically diverging preferences. What is conceptualized as “in front” in one variant of the relative FoR (e.g., translation) is “behind” under another variant (reflection), and vice versa. Do such diverging conceptualizations of an object's location also lead to diverging evaluations? In two studies employing an implicit association test, we demonstrate, first, that speakers of German, Chinese, and Japanese indeed evaluate the object “in front of” another object more positively than the one “behind.” Second, and crucially, the reversal of which object is conceptualized as “in front” involves a corresponding reversal of valence, suggesting an impact of linguistically imparted FoR preferences on evaluative processes.publishedVersio

Moving beyond Goffman: the performativity of anonymity on SNS

Purpose: This paper explores consumer behaviour on the popular anonymous social networking site (SNS) Yik Yak. It examines the reasons behind the turn to anonymous social networking and also considers the ways in which anonymity impacts consumers' self-performances on SNS. Design/methodology/approach: The study used a netnographic approach to explore Yik Yak across eight universities in Ireland and the UK. Data are based on observation and participation on the app. Screenshots on smart phones were the central method used to collect data. Data also included twelve in-depth interviews. Findings: Young consumers are becoming fatigued by the negative effects of self-presentation on many SNS. By enabling consumers to engage in what they consider to be more authentic modes of being and interaction, Yik Yak provides respite from these pressures. Through the structures of its design, Yik Yak enables consumers to realise self-authentication in anonymised self-performances that engender a sense of virtue and social connection. Originality/value: By invoking a performative lens, this paper extends a novel theoretical approach to understandings of identity formation within consumer research. Highlighting anonymity as a dynamic process of socio- material enactments, the study reveals how consumers' self-performances are brought into effect through the citation of various discursive arrangements, which promulgate distinct understandings of authenticity. Practical implications: This research highlights the potential value of anonymous SNS in fostering supportive dialogue, concerning mental health amongst post-millennials

A personalized and platform-independent behavior control system for social robots in therapy: Development and applications

Social robots have been proven beneficial in different types of healthcare interventions. An ongoing trend is to develop (semi-)autonomous socially assistive robotic systems in healthcare context to improve the level of autonomy and reduce human workload. This paper presents a behavior control system for social robots in therapies with a focus on personalization and platform-independence. This system architecture provides the robot an ability to behave as a personable character, which behaviors are adapted to user profiles and responses during the human-robot interaction. Robot behaviors are designed at abstract levels and can be transferred to different social robot platforms. We adopt the component-based software engineering approach to implement our proposed architecture to allow for the replaceability and reusability of the developed components. We introduce three different experimental scenarios to validate the usability of our system. Results show that the system is potentially applicable to different therapies and social robots. With the component-based approach, the system can serve as a basic framework for researchers to customize and expand the system for their targeted healthcare applications

Constructing the digitalized sporting body: black and white masculinity in NBA/NHL internet memes

In this article, I examine the ways sport fans construct and circulate discourses of race and masculinity in cyberspace. I do this through an examination of a set of Internet memes that juxtapose the bodies of National Hockey League players with National Basketball Association players in one single image. I argue these memes celebrate White masculinity, while at the same time constructing African American athletes as individualistic, selfish, and unwilling to sacrifice their bodies for the greater good of the team. More so, I argue that these memes construct a form of racial ideology that is representative of White backlash politics

Instagrammatics and digital methods: Studying visual social media, from selfies and GIFs to memes and emoji

Visual content is a critical component of everyday social media, on platforms explicitly framed around the visual (Instagram and Vine), on those offering a mix of text and images in myriad forms (Facebook, Twitter, and Tumblr), and in apps and profiles where visual presentation and provision of information are important considerations. However, despite being so prominent in forms such as selfies, looping media, infographics, memes, online videos, and more, sociocultural research into the visual as a central component of online communication has lagged behind the analysis of popular, predominantly text-driven social media. This paper underlines the increasing importance of visual elements to digital, social, and mobile media within everyday life, addressing the significant research gap in methods for tracking, analysing, and understanding visual social media as both image-based and intertextual content.In this paper, we build on our previous methodological considerations of Instagram in isolation to examine further questions, challenges, and benefits of studying visual social media more broadly, including methodological and ethical considerations. Our discussion is intended as a rallying cry and provocation for further research into visual (and textual and mixed) social media content, practices, and cultures, mindful of both the specificities of each form, but also, and importantly, the ongoing dialogues and interrelations between them as communication forms

The structure-function relationships of a natural nanoscale photonic device in cuttlefish chromatophores

Cuttlefish, Sepia officinalis, possess neurally controlled, pigmented chromatophore organs that allow rapid changes in skin patterning and coloration in response to visual cues. This process of adaptive coloration is enabled by the 500% change in chromatophore surface area during actuation. We report two adaptations that help to explain how colour intensity is maintained in a fully expanded chromatophore when the pigment granules are distributed maximally: (i) pigment layers as thin as three granules that maintain optical effectiveness and (ii) the presence of high-refractive-index proteins—reflectin and crystallin—in granules. The latter discovery, combined with our finding that isolated chromatophore pigment granules fluoresce between 650 and 720 nm, refutes the prevailing hypothesis that cephalopod chromatophores are exclusively pigmentary organs composed solely of ommochromes. Perturbations to granular architecture alter optical properties, illustrating a role for nanostructure in the agile, optical responses of chromatophores. Our results suggest that cephalopod chromatophore pigment granules are more complex than homogeneous clusters of chromogenic pigments. They are luminescent protein nanostructures that facilitate the rapid and sophisticated changes exhibited in dermal pigmentation.Engineering and Applied Science