LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Operationalizing behavior change theory as part of persuasive technology: A scoping review on social comparison

Theories from psychology or the social sciences are commonly used as a starting point when designing persuasive technologies that aim to evoke a specific behavior change. Ideally, using these theories would (1) help guide the design of the persuasive technology and (2) help evaluate and inform the theory. In this paper, we focused on the first aspect and looked at how papers report on how a theory guided the design of persuasive technology. We performed a scoping review focused on the operationalization of social comparison theory as part of persuasive design. We chose social comparison due to its ubiquitous use in persuasive design as well as its potential positive or negative influence on the user. The former requires careful consideration in a persuasive design prototype. We focused on the proceedings of the Persuasive Technology conference from 2006 to 2020 to gain an understanding of the use of social comparison theory as part of persuasive design. Twelve studies met our inclusion criteria. Explanations of how the theory guides design decisions leading to the final operationalization were sparse. We suggest that conducting manipulation checks and using a systematic approach to reporting design decisions including the potential grounding of design elements in theory could highlight and clarify theoretical insights, and could increase our understanding of how social comparison—and behavior change theory in general—could be efficiently operationalized in persuasive technologies.Design Aesthetic

The three-step persuasion model on YouTube: A grounded theory study on persuasion in the protein supplements industry

Persuasion can be defined as an active attempt by a person to change the behavior and attitudes of others. The purposive attempt to influence one’s behavior can originate from different areas, and people who are able to do so are often referred to as influencers. Social media platforms such as Instagram or YouTube have become crucial platforms for influencers who generate their income by recommending products and services to their followers, including cosmetics, multimedia articles or clothing. Studies indicate that influencers actively try to persuade the viewer to adopt specific desirable behavior by strategically altering their displayed behavior on social media. Such strategies have mainly been explored in the context of beauty products, where lack of expertise and misinformation might have few negative consequences. Less is known about strategies used in a health-sensitive context, such as nutritional supplements. This research addresses this gap and aims to understand persuasive techniques used by health professionals on YouTube to promote the use of protein supplements. This study is based on an interpretive paradigm using interpretive grounded theory to analyze 60 YouTube videos. We developed a three-step model of persuasion for YouTube videos consisting of the steps: reaching the message, staying on the message, and performing the action that the persuader desires. Our analysis resulted in five core themes that contributed to the persuasiveness of the analyzed YouTube videos. These themes included: Quality, curiosity, engagement, concretization, and genuineness. We conclude the paper with reflections on our model’s theoretical and practical implications.Design Aesthetic

Mattpod: A Design Proposal for a Multi-Sensory Solo Dining Experience

The consumption of a meal is not just a bodily requirement but can also carry significant symbolic meaning. Solo dining is often contrasted to a shared eating experience and portrayed as an inferior way of eating a meal due to lacking essential social and normative qualities. Human-computer interaction research increasingly explores different ways of enhancing the solo dining experience. However, a focus seems to be on recreating aspects essential to the shared eating experience, such as a dining companion being present, rather than trying to enhance aspects that solo diners enjoy and, therefore, contribute to a reverie in eating. Based on earlier research findings, we developed a design concept that includes sound and visual elements supporting the multi-sensory eating experience and encouraging the user to concentrate on the food rather than seeking distraction. The formative usability evaluation results indicate that the proposed design needs further refinement to evoke the anticipated effect.Design Aesthetic

Commensality or Reverie in Eating? Exploring the Solo Dining Experience

Commensality, the act of eating together, is commonly associated with many benefits. Dining solo, in contrast, is frequently connected to adverse effects on a person. There is a growing interest in human-computer interaction (HCI) and design in how innovations can enhance eating experiences by, for example, facilitating commensality. The steadily growing number of people eating alone and the associated risks beg the question of how HCI and design could contribute to and improve the solo dining experience and whether or not mimicking or facilitating commensality is what solo diners want. This two-phased study reports on the context exploration of the multimodal solitary dining experience. In the first phase, we scoped the literature describing the benefits and drawbacks of solo dining and commensality. For the second phase, a digital food diary was developed and completed by six solo diners to collect further insights and user requirements. Photos and annotations collected as part of the food diary were analyzed using content analysis. The results indicate several advantages of eating alone, including feeling relaxed, perceiving solo dining as a moment of self-pampering, and appreciating the cooking experience. Overall, it seems that solo dining is not merely a lack of commensality, but a unique experience in and of itself, where people seem to strive towards finding reverie in eating.Design Aesthetic

Experts Get Me Started, Peers Keep Me Going: Comparing Crowd- versus Expert-Designed Motivational Text Messages for Exercise Behavior Change

We present a comparative analysis of motivational messages designed with a theory-driven approach. A previous study [4] involved crowdsourcing to design and evaluate motivational text messages for physical activity, and showed that these peer-designed text messages aligned to behavior change strategies from theory. However, the messages were predominantly rated as motivating in the later stages of behavior change, not in the earlier stages, including those strategies intended for the earlier stages. We speculated that the peers that designed the messages aligned to the strategies did not have sufficient expertise to motivate people in earlier stages. Therefore, we replicated the study with experts. We found that for two of the strategies expert-designed messages were found more motivating in the earliest stage, while for several of the strategies peer-designed messages were rated more motivating for later stages. We conclude that when using these strategies in behavior change technology, expert-designed messages could be more motivating in the earliest stage, while peer-designed messages could be more motivating in the later stages

Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity

NR4A nuclear receptors are induced in the liver upon fasting and regulate hepatic gluconeogenesis. Here, we studied the role of nuclear receptor Nur77 (NR4A1) in hepatic lipid metabolism. We generated mice expressing hepatic Nur77 using adenoviral vectors, and demonstrate that these mice exhibit a modulation of the plasma lipid profile and a reduction in hepatic triglyceride. Expression analysis of >25 key genes involved in lipid metabolism revealed that Nur77 inhibits SREBP1c expression. This results in decreased SREBP1c activity as is illustrated by reduced expression of its target genes stearoyl-coA desaturase-1, mitochondrial glycerol-3-phosphate acyltransferase. fatty acid synthase and the LDL receptor, and provides a mechanism for the physiological changes observed in response to Nur77. Expression of LXR target genes Abcg5 and Abcg8 is reduced by Nur77, and may suggest involvement of LXR in the inhibitory action of Nur77 on SREBP1c expression. Taken together, our study demonstrates that Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity. (c) 2007 Elsevier Inc. All rights reserve