803 research outputs found

    The Evolutionary Price of Anarchy: Locally Bounded Agents in a Dynamic Virus Game

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    The Price of Anarchy (PoA) is a well-established game-theoretic concept to shed light on coordination issues arising in open distributed systems. Leaving agents to selfishly optimize comes with the risk of ending up in sub-optimal states (in terms of performance and/or costs), compared to a centralized system design. However, the PoA relies on strong assumptions about agents\u27 rationality (e.g., resources and information) and interactions, whereas in many distributed systems agents interact locally with bounded resources. They do so repeatedly over time (in contrast to "one-shot games"), and their strategies may evolve. Using a more realistic evolutionary game model, this paper introduces a realized evolutionary Price of Anarchy (ePoA). The ePoA allows an exploration of equilibrium selection in dynamic distributed systems with multiple equilibria, based on local interactions of simple memoryless agents. Considering a fundamental game related to virus propagation on networks, we present analytical bounds on the ePoA in basic network topologies and for different strategy update dynamics. In particular, deriving stationary distributions of the stochastic evolutionary process, we find that the Nash equilibria are not always the most abundant states, and that different processes can feature significant off-equilibrium behavior, leading to a significantly higher ePoA compared to the PoA studied traditionally in the literature

    The Psychological Impacts and Message Features of Health Misinformation

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    What does health misinformation look like, and what is its impact? We conducted a systematic review of 45 articles containing 64 randomized controlled trials (RCTs; N = 37,552) on the impact of health misinformation on behaviors and their psychological antecedents. We applied a planetary health perspective by framing environmental issues as human health issues and focusing on misinformation about diseases, vaccination, medication, nutrition, tobacco consumption, and climate change. We found that in 49% of the cases exposure to health misinformation damaged the psychological antecedents of behaviors such as knowledge, attitudes, or behavioral intentions. No RCTs evaluated the impact of exposure to misinformation on direct measures of health or pro-environmental behaviors (e.g., vaccination), and few studies explored the impact of misinformation on feelings, social norms, and trust. Most misinformation was based on logical fallacies, conspiracy theories, or fake experts. RCTs evaluating the impact of impossible expectations and cherry-picking are scarce. Most research focused on healthy adult US populations and used online samples. Future RCTs can build on our analysis and address the knowledge gaps we identified

    LCD vs. E-ink: An Analysis of the Reading Behavior

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    Electronic books (e-book) are an interesting option compared to classic paper books. Most e-reading devices of the first generation were based on e-ink technology. With the appearance of the Apple iPad on the market, TFT-LCDs became important in the field of e-reading. Both technologies have advantages and disadvantages but the question remains whether one or the other technology is better for reading. In the present study we analyzed and compared reading behavior when reading on e-inkreader (e-ink displays) and on tablets (TFT-LCDs) as measured by eye-tracking. The results suggest that the reading behavior on tablets is indeed very similar to the reading behavior on e-ink-reader. Participants showed no difference in fixation duration. Significant differences in reading speed and in the proportion of regressive saccades suggest that tablets, under special artificial light conditions, may even provide better legibility

    The evolution of indirect reciprocity under action and assessment generosity

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    Indirect reciprocity is a mechanism for the evolution of cooperation based on social norms. This mechanism requires that individuals in a population observe and judge each other’s behaviors. Individuals with a good reputation are more likely to receive help from others. Previous work suggests that indirect reciprocity is only effective when all relevant information is reliable and publicly available. Otherwise, individuals may disagree on how to assess others, even if they all apply the same social norm. Such disagreements can lead to a breakdown of cooperation. Here we explore whether the predominantly studied ‘leading eight’ social norms of indirect reciprocity can be made more robust by equipping them with an element of generosity. To this end, we distinguish between two kinds of generosity. According to assessment generosity, individuals occasionally assign a good reputation to group members who would usually be regarded as bad. According to action generosity, individuals occasionally cooperate with group members with whom they would usually defect. Using individual-based simulations, we show that the two kinds of generosity have a very different effect on the resulting reputation dynamics. Assessment generosity tends to add to the overall noise and allows defectors to invade. In contrast, a limited amount of action generosity can be beneficial in a few cases. However, even when action generosity is beneficial, the respective simulations do not result in full cooperation. Our results suggest that while generosity can favor cooperation when individuals use the most simple strategies of reciprocity, it is disadvantageous when individuals use more complex social norms

    Metapholio: A mobile app for supporting collaborative note taking and reflection in teacher education

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    Mobile technologies open up new ways of fostering reflection in teacher education. With the intention of tying reflection closer to the actions in the classroom, facilitating multimedia recordings, providing prompts for reflection and fostering discussions between pre-service teachers, experienced teachers and university mentors, we developed the “Metapholio” app and tested it in the context of teaching internships. This app supports pre-service teachers in collecting noteworthy moments in the classroom by providing functionalities for individual and collaborative note taking. Notes can be created in the form of written text, photography, audio recordings and video recordings. Each note can be commented on and discussed with invited peers, experienced teachers and university mentors, who can also record moments themselves. Furthermore, the app makes it possible to select notes and attach them to more general written or spoken reflections on teaching and learning. Theoretical frameworks and writing prompts that are part of the app serve as scaffolds for such reflections. Peers, teachers and mentors can be invited to join the conversation on reflections. With the help of this app, pre-service teachers can, moreover, create their own multimedia mobile portfolio, which acts as a hybrid space for professional development in teacher education

    The known unknowns of the Hsp90 chaperone

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    Molecular chaperones are vital proteins that maintain protein homeostasis by assisting in protein folding, activation, degradation, and stress protection. Among them, heat-shock protein 90 (Hsp90) stands out as an essential proteostasis hub in eukaryotes, chaperoning hundreds of "clients" (substrates). After decades of research, several "known unknowns" about the molecular function of Hsp90 remain unanswered, hampering rational drug design for the treatment of cancers, neurodegenerative and other diseases. We highlight three fundamental open questions, reviewing the current state of the field for each, and discuss new opportunities, including single-molecule technologies, to answer the known unknowns of the Hsp90 chaperone.Comment: 29 pages, 4 figure

    Profile of patients diagnosed with AIDS at age 60 and above in Brazil, from 1980 until June 2009, compared to those diagnosed at age 18 to 59.

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    OBJECTIVES: The aim of this study was to learn more about people diagnosed with acquired immunodeficiency syndrome (AIDS) at age 60 and above in Brazil, and to compare them with people diagnosed at a younger age. METHODS: This study was based on the analysis of secondary data from the Brazilian AIDS Program. The study population consisted of people diagnosed with AIDS at age 60 and above. The comparison group was comprised of a 20% random sample of people diagnosed at age 18 to 59, frequency-matched by year of diagnosis. RESULTS: 544,846 cases of AIDS were reported in Brazil from 1980 until June 2009. Over 90% of cases were diagnosed between 18 and 59 years of age, and 13,657 (2.5%) at age 60 and above. The first case of AIDS among the elderly was reported in 1984. The comparison group consisted of 101,528 patients. Gender proportion was similar for both groups, and the proportion of people identified with AIDS after death in the Brazilian Mortality Information System (SIM) was 4% higher among the elderly. Both groups were also similar regarding the region of residence; a markedly higher proportion lived in Southeastern Brazil. Older people were more likely to have lower education and to have contracted AIDS by heterosexual contact, and less likely to be intravenous drug users. Male to female ratio among those diagnosed with AIDS at or above age 60 decreased over the years, in the same way as observed for the whole cohort. Mortality was higher among men in both groups. CD4 category (taken closest to the date of AIDS diagnosis) was very similar in both groups. CONCLUSION: The characteristics of the epidemic among the elderly show similarities to the younger group considering gender distribution and CD4 category, but differ regarding educational level and exposure category. Also, the elderly were more likely not to have their AIDS condition promptly diagnosed

    Adequacy of the production rules

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    Adequacy of the production rules
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