A novel AhR ligand, 2AI, protects the retina from environmental stress.

Various retinal degenerative diseases including dry and neovascular age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy are associated with the degeneration of the retinal pigmented epithelial (RPE) layer of the retina. This consequently results in the death of rod and cone photoreceptors that they support, structurally and functionally leading to legal or complete blindness. Therefore, developing therapeutic strategies to preserve cellular homeostasis in the RPE would be a favorable asset in the clinic. The aryl hydrocarbon receptor (AhR) is a conserved, environmental ligand-dependent, per ARNT-sim (PAS) domain containing bHLH transcription factor that mediates adaptive response to stress via its downstream transcriptional targets. Using in silico, in vitro and in vivo assays, we identified 2,2'-aminophenyl indole (2AI) as a potent synthetic ligand of AhR that protects RPE cells in vitro from lipid peroxidation cytotoxicity mediated by 4-hydroxynonenal (4HNE) as well as the retina in vivo from light-damage. Additionally, metabolic characterization of this molecule by LC-MS suggests that 2AI alters the lipid metabolism of RPE cells, enhancing the intracellular levels of palmitoleic acid. Finally, we show that, as a downstream effector of 2AI-mediated AhR activation, palmitoleic acid protects RPE cells from 4HNE-mediated stress, and light mediated retinal degeneration in mice

Aerodynamic Models for the Low Density Supersonic Declerator (LDSD) Supersonic Flight Dynamics Test (SFDT)

An overview of pre-flight aerodynamic models for the Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) campaign is presented, with comparisons to reconstructed flight data and discussion of model updates. The SFDT campaign objective is to test Supersonic Inflatable Aerodynamic Decelerator (SIAD) and large supersonic parachute technologies at high altitude Earth conditions relevant to entry, descent, and landing (EDL) at Mars. Nominal SIAD test conditions are attained by lifting a test vehicle (TV) to 36 km altitude with a large helium balloon, then accelerating the TV to Mach 4 and and 53 km altitude with a solid rocket motor. The first flight test (SFDT-1) delivered a 6 meter diameter robotic mission class decelerator (SIAD-R) to several seconds of flight on June 28, 2014, and was successful in demonstrating the SFDT flight system concept and SIAD-R. The trajectory was off-nominal, however, lofting to over 8 km higher than predicted in flight simulations. Comparisons between reconstructed flight data and aerodynamic models show that SIAD-R aerodynamic performance was in good agreement with pre-flight predictions. Similar comparisons of powered ascent phase aerodynamics show that the pre-flight model overpredicted TV pitch stability, leading to underprediction of trajectory peak altitude. Comparisons between pre-flight aerodynamic models and reconstructed flight data are shown, and changes to aerodynamic models using improved fidelity and knowledge gained from SFDT-1 are discussed

Age Constraints on Brane Models of Dark Energy

Inspired by recent developments in particle physics, the so-called brane world cosmology seems to provide an alternative explanation for the present dark energy problem. In this paper, we use the estimated age of high-$z$ objects to constrain the value of the cosmological parameters in some particular scenarios based on this large scale modification of gravity. We show that such models are compatible with these observations for values of the crossover distance between the 4 and 5 dimensions of the order of $r_c \leq 1.67H_o^{-1}$.Comment: 4 pages, 2 figures, 1 table, to appear in Phys. Rev.

Mutual Knowledge and its Impact on Virtual Team Performance

This paper describes the notion of mutual knowledge and its potential impact on virtual team performance. Based on a review of the literature, including proponents and opponents for the concept of mutual knowledge in group interaction, we suggest that there is a gap in our understanding of what is known about mutual knowledge as it impacts team dynamics and ultimately virtual team performance. We conclude the paper by discussing the importance of mutual knowledge for virtual team performance and the research issues that need to be addressed in this domain

The Influence of Online Word of Mouth on Product Sales in Retail E-commerce: An Empirical Investigation

The ability to exchange opinions and experiences online is known as online word of mouth (WOM). Due to the high acceptance of consumers and their apparent reliance on online WOM it is important for organizations to understand how it works and what kind of impact it has on product sales. Using the well-established notions of volume and valence to describe online WOM, we empirically evaluate the hypothesized relationship between online WOM in a retail e-commerce site and actual product sales. Our analysis of the data shows that there is a significant change in the number of products sold following the addition of online WOM to a retail e-commerce site’s product pages. Additionally, only the volume dimension of online WOM, measured by the number of customer review comments, is shown to have an influence on product sales

An Empirical Study of Online Word of Mouth as a Predictor for Multi-product Category e-Commerce Sales

The ability to exchange opinions and experiences online is known as online word of mouth (WOM) and has been shown in the literature to have the potential to impact e-commerce sales. The purpose of this paper is to expand previous findings by empirically evaluating the impact of online WOM attributes and other related factors (e.g. product views, promotion, and category) on e-commerce sales using real data from a multi-product retail e-commerce firm. Research has previously shown that the introduction of online WOM on a retail e-commerce site can positively impact product sales. We propose and validate a conceptual model of online WOM and its impact on product sales and the impact of moderator variables such as promotion, product category and product views. It is our conclusion that previous research on online WOM has been limited as our research empirically demonstrates the conclusion that it is the interaction of product category, volume and product views, and the interaction of product views and product category which are statistically significant in explaining changes in unit product sales. Pure increase in volume or number of reviewer comments has no significant effect on sales. These conclusions have critical implications for the practical use of online WOM in e-commerce and for internet marketing

Does Mutual Knowledge Affect Virtual Team Performance? Theoretical Analysis and Anecdotal Evidence

This paper describes the concept of mutual knowledge and its potential impact on virtual team performance. Based on an analysis of extant literature, we argue that there is a gap in our understanding of what is known about mutual knowledge as it impacts team dynamics and virtual team performance. Supporting literature, anecdotes, and case studies are used to discuss the importance of mutual knowledge for virtual team performance and the research issues that need to be addressed in the future

An Empirical Investigation of Virtual World Projects and Metaverse Technology Capabilities

Metaverses are immersive three-dimensional virtual worlds (VWs) where people interact with each other and their environment, using the metaphor of the real world but without its physical limitations. Unique technology capabilities of metaverses have the potential to enhance the conduct of virtual projects, but little is known about virtual worlds in this context. Virtual project teams struggle in meeting stated project outcomes due to challenges related to communication, shared understanding, and coordination. One way to address these challenges is to consider the use of emerging technologies, such as metaverses, to minimize the impact on virtual project teams. Applying a theoretical foundation for virtual teams in metaverses that includes both technology capabilities and the social interaction that takes place in the metaverse environment, we conducted an empirical investigation of project teams in a virtual world setting. The study examined the interplay of communication, representation, interaction, and team process tools with behaviors that led to role clarity, shared understanding, and coordination. While each individual technology capability contributed to project execution and outcomes, much of the power of the environment emerged through the interplay of social behaviors and technology capabilities. The results have intriguing implications for how metaverse technology capabilities might provide new ways to address gaps in the current research and practice of virtual project management and virtual teams

Avatars, People, and Virtual Worlds: Foundations for Research in Metaverses

Metaverses are immersive three-dimensional virtual worlds in which people interact as avatars with each other and with software agents, using the metaphor of the real world but without its physical limitations. The ubiquitous availability of high speed Internet access has spurred enormous interest in virtual worlds like Second Life and World of Warcraft, both in terms of user gaming and as a new technological platform for global virtual collaboration. These environments have potential for richer, more engaging collaboration, but their capabilities have yet to be examined in depth. Of particular interest in this paper is the use of metaverses for virtual team collaboration. We develop a conceptual model for research in metaverses that is based on five key constructs: (1) the metaverse itself, (2) people/avatars, (3) metaverse technology capabilities, (4) behaviors, and (5) outcomes. We present an in-depth characterization of metaverse technology capabilities from a socio-technical view that recognizes the potential for variation in emergent interaction and in outcomes. Example propositions and a discussion of key issues and challenges show how the model can be used to further research and practice in virtual teams in the context of these new environments