Research about vection (illusory self-motion) has investigated a wide range of sensory cues and employed various methods and equipment, including use of virtual reality (VR). However, there is ...currently no research in the field of vection on the impact of floating in water while experiencing VR. Aquatic immersion presents a new and interesting method to potentially enhance vection by reducing conflicting sensory information that is usually experienced when standing or sitting on a stable surface. This study compares vection, visually induced motion sickness, and presence among participants experiencing VR while standing on the ground or floating in water. Results show that vection was significantly enhanced for the participants in the Water condition, whose judgments of self-displacement were larger than those of participants in the Ground condition. No differences in visually induced motion sickness or presence were found between conditions. We discuss the implication of this new type of VR experience for the fields of VR and vection while also discussing future research questions that emerge from our findings.
Climate change impacts are felt globally, and the impacts are increasing in severity and intensity. Developing new interventions to encourage behaviors that address climate change is crucial. This ...pre-registered field study investigated how the design of a virtual reality (VR) experience about ocean acidification could impact participants’ learning, behavior, and perceptions about climate change through the manipulation of the experience message framing, the sex of voice-over and the pace of the experience, and the amount of participants’ body movement. The study was run in 17 locations such as museums, aquariums, and arcades in the U.S., Canada, the U.K., and Denmark. The amount of body movement was a causal mechanism, eliciting higher feelings of self-efficacy while hindering learning. Moreover, linking the VR narrative about ocean acidification linguistically to climate change impaired learning compared to a message framing that did not make the connection. As participants learned more about the experience, they perceived the risks associated with ocean acidification as higher, and they were more likely to engage in pro-climate behavior. The results shed light on the mechanisms behind how VR can teach about ocean acidification and influence climate change behavior.
Immersive virtual reality (IVR) provides great potential to experimentally investigate effects of peers on student learning in class and to strategically deploy virtual peer learners to improve ...learning. The present study examined how three social-related classroom configurations (i.e., students' position in the classroom, visualization style of virtual avatars, and virtual classmates' performance-related behavior) affect students' visual attention toward information presented in the IVR classroom using a large-scale eye-tracking data set of N = 274 sixth graders. ANOVA results showed that the IVR configurations were systematically associated with differences in learners' visual attention on classmates or the instructional content and their overall gaze distribution in the IVR classroom (Cohen's d ranging from 0.28 to 2.04 for different IVR configurations and gaze features). Gaze-based attention on classmates was negatively related to students' interest in the IVR lesson (d = 0.28); specifically, the more boys were among the observed peers, the lower students' situational self-concept (d = 0.24). In turn, gaze-based attention on the instructional content was positively related to students' performance after the IVR lesson (d = 0.26). Implications for the future use of IVR classrooms in educational research and practice are discussed.
•Peer effects in an immersive virtual reality (IVR) classroom with 24 simulated virtual classmates as social counterparts•Different social-related IVR classroom configurations regarding students' position, avatar visualization, and peer behavior•Large-scale eye-tracking data set to describe sixth graders' visual attention during instruction in the IVR classroom•Social-related IVR configuration features affect students' visual attention distribution during instruction•Gaze-based attention networks show relationships to students' interest and learning in the IVR classroom
ABSTRACT
We use data of ∼13 000 stars from the Sloan Digital Sky Survey/Apache Point Observatory Galactic Evolution Experiment survey to study the shape of the bulge metallicity distribution function ...(MDF) within the region |ℓ| ≤ 11° and |b| ≤ 13°, and spatially constrained to RGC ≤ 3.5 kpc. We apply Gaussian mixture modelling and non-negative matrix factorization decomposition techniques to identify the optimal number and the properties of MDF components. We find that the shape and spatial variations of the MDF (at Fe/H ≥ −1 dex) are well represented as a smoothly varying contribution of three overlapping components located at Fe/H = +0.32, −0.17, and −0.66 dex. The bimodal MDF found in previous studies is in agreement with our trimodal assessment once the limitations in sample size and individual measurement errors are taken into account. The shape of the MDF and its correlations with kinematics reveal different spatial distributions and kinematical structure for the three components co-existing in the bulge region. We confirm the consensus physical interpretation of metal-rich stars as associated with the secularly evolved disc into a boxy/peanut X-shape bar. On the other hand, metal-intermediate stars could be the product of in-situ formation at high redshift in a gas-rich environment characterized by violent and fast star formation. This interpretation would help us to link a present-day structure with those observed in formation in the centre of high-redshift galaxies. Finally, metal-poor stars may correspond to the metal-rich tail of the population sampled at lower metallicity from the study of RR Lyrae stars. Conversely, they could be associated with the metal-poor tail of the early thick disc.
The central (‘bulge’) region of the Milky Way is teeming with a significant fraction of mildly metal-deficient stars with atmospheres that are strongly enriched in cyanogen (
12
C
14
N). Some of ...these objects, which are also known as nitrogen-enhanced stars, are hypothesised to be relics of the ancient assembly history of the Milky Way. Although the chemical similarity of nitrogen-enhanced stars to the unique chemical patterns observed in globular clusters has been observed, a direct connection between field stars and globular clusters has not yet been proven. In this work, we report on high-resolution, near-infrared spectroscopic observations of the bulge globular cluster NGC 6723, and the serendipitous discovery of a star, 2M18594405−3651518, located outside the cluster (near the tidal radius) but moving on a similar orbit, providing the first clear piece of evidence of a star that was very likely once a cluster member and has recently been ejected. Its nitrogen abundance ratio (N/Fe ≳ + 0.94) is well above the typical Galactic field-star levels, and it exhibits noticeable enrichment in the heavy
s
-process elements (Ce, Nd, and Yb), along with moderate carbon enrichment; all characteristics are known examples in globular clusters. This result suggests that some of the nitrogen-enhanced stars in the bulge likely originated from the tidal disruption of globular clusters.
Abstract
In this work, we study the phase-space and chemical properties of the Sagittarius (Sgr) stream, the tidal tails produced by the ongoing destruction of the Sgr dwarf spheroidal (dSph) galaxy, ...focusing on its very metal-poor (VMP; Fe/H < −2) content. We combine spectroscopic and astrometric information from SEGUE and Gaia EDR3, respectively, with data products from a new large-scale run of the
StarHorse
spectrophotometric code. Our selection criteria yield ∼1600 stream members, including >200 VMP stars. We find the leading arm (
b
> 0°) of the Sgr stream to be more metal-poor, by ∼0.2 dex, than the trailing one (
b
< 0°). With a subsample of turnoff and subgiant stars, we estimate this substructure’s stellar population to be ∼1 Gyr older than the thick disk’s. With the aid of an
N
-body model of the Sgr system, we verify that simulated particles stripped earlier (>2 Gyr ago) have present-day phase-space properties similar to lower metallicity stream stars. Conversely, those stripped more recently (<2 Gyr) are preferentially akin to metal-rich (Fe/H > −1) members of the stream. Such correlation between kinematics and chemistry can be explained by the existence of a dynamically hotter, less centrally concentrated, and more metal-poor population in Sgr dSph prior to its disruption, implying that this galaxy was able to develop a metallicity gradient before its accretion. Finally, we identified several carbon-enhanced metal-poor (C/Fe > +0.7 and Fe/H ≤ −1.5) stars in the Sgr stream, which might be in tension with current observations of its remaining core where such objects are not found.
Previous analyses of large databases of Milky Way stars have revealed the stellar disk of our Galaxy to be warped and that this imparts a strong signature on the kinematics of stars beyond the solar ...neighborhood. However, due to the limitation of accurate distance estimates, many attempts to explore the extent of these Galactic features have generally been restricted to a volume near the Sun. By combining the Gaia DR2 astrometric solution, StarHorse distances, and stellar abundances from the APOGEE survey, we present the most detailed and radially expansive study yet of the vertical and radial motions of stars in the Galactic disk. We map velocities of stars with respect to their Galactocentric radius, angular momentum, and azimuthal angle and assess their relation to the warp. A decrease in vertical velocity is discovered at Galactocentric radius R = 13 kpc and angular momentum Lz = 2800 kpc km s−1. Smaller ripples in vertical and radial velocity are also discovered superposed on the main trend. We also discovered that trends in the vertical velocity with azimuthal angle are not symmetric about the peak, suggesting the warp is lopsided. To explain the global trend in vertical velocity, we built a simple analytical model of the Galactic warp. Our best fit yields a starting radius of and precession rate of . These parameters remain consistent across stellar age groups, a result that supports the notion that the warp is the result of an external, gravitationally induced phenomenon.
Ocean Acidification (OA) is an emerging environmental issue that is still largely unknown to the public and in its infancy in terms of educational strategies. OA teaching material should address the ...specific challenges that educators face while building learners' understanding of OA. The objective of this study is two-fold. First, we identified the barriers to teaching OA as experienced by formal and informal marine educators. Second, we provided educators an opportunity to experience virtual reality and discuss how it could serve as a tool for face-to-face and distance learning to address the identified challenges. The findings shed light on four overarching themes of challenges to teaching OA: lack of science literacy, unprepared education field, complex and invisible nature of OA and lack of personal connection with the ocean. Marine educators consider empowerment, perspective-taking and visualization as the three principal avenues through which virtual reality may contribute to mitigating the challenges to teaching OA.
Abstract
We identified eight additional stars as members of the Helmi stream (HStr) in the combined GALAH+ DR3 and Gaia EDR3 catalog. By consistently reevaluating claimed members from the literature, ...we consolidate a sample of 22 HStr stars with parameters determined from high-resolution spectroscopy and spanning a considerably wider (by ∼0.5 dex) metallicity interval (− 2.5 ≲ Fe/H < − 1.0) than previously reported. Our study focuses on
α
(Mg and Ca) and neutron-capture (Ba and Eu) elements. We find that the chemistry of HStr is typical of dwarf spheroidal (dSph) galaxies, in good agreement with previous
N
-body simulations of this merging event. Stars of HStr constitute a clear declining sequence in
α
/Fe for increasing metallicity up to Fe/H ∼ −1.0. Moreover, stars of HStr show a median value of +0.5 dex for Eu/Fe with a small dispersion (±0.1 dex). Every star analyzed with Fe/H < −1.2 belongs to the
r
-process enhanced (Eu/Fe > +0.3 and Ba/Eu < 0.0) metal-poor category, providing remarkable evidence that, at such a low-metallicity regime, stars of HStr experienced enrichment in neutron-capture elements predominantly via
r
-process nucleosynthesis. Finally, the extended metallicity range also suggests an increase in Ba/Eu for higher Fe/H, in conformity with other surviving dwarf satellite galaxies of the Milky Way.
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