Based on the results of two laboratory studies, we show how the implementation of minimalistic social and task-relevant cues in Augmented Reality-based assistance systems for spatially dispersed ...teams impact team experience while not affecting team performance. In study 1 (
N
= 224) we investigated the Ambient Awareness Tool, which supports spatially dispersed teams in their temporal coordination when multiple team tasks or team and individual tasks must be executed in parallel. We found that adding a progress bar to the interface led to a significant increase in the perception of work group cohesiveness (diff = 0.34,
p
= .03, CI: −0.65; −0.03,
d
= 0.39), but did not affect team performance (
p
= .92, η
2
= 0.03). In study 2 (
N
= 23) we piloted an AR-based avatar representation of a spatially dispersed team member and evaluated whether the interactivity of the avatar impacts the perception of co- and social presence as well as team performance. An interactive avatar increased the perception of co- and social presence (co-presence: diff = 2.7,
p
< .001, η
2
= 0.20; social presence: diff = 1.2,
p
= .001, η
2
= 0.06). Team performance did not differ significantly (
p
= .177, η
2
= 0.01). These results indicate that even minor social and task-relevant cues in the interface can significantly impact team experience and provide valuable insights for designing human-centered health-promoting AR-based assistance systems for spatially dispersed teams in the vocational context with minimal means.
The inquiry into the impact of diverse transitions between cross-reality environments on user experience remains a compelling research endeavor. Existing work often offers fragmented perspectives on ...various techniques or confines itself to a singular segment of the reality-virtuality spectrum, be it virtual reality or augmented reality. This study embarks on bridging this knowledge gap by systematically assessing the effects of six prevalent transitions while users remain immersed in tasks spanning both virtual and physical domains. In particular, we investigate the effect of different transitions while the user is continuously engaged in a demanding task instead of purely focusing on a given transition. As a preliminary step, we evaluate these six transitions within the realm of pure virtual reality to establish a baseline. Our findings reveal a clear preference among participants for brief and efficient transitions in a task-driven experience, instead of transitions that prioritize interactivity and continuity. Subsequently, we extend our investigation into a cross-reality context, encompassing transitions between virtual and physical environments. Once again, our results underscore the prevailing preference for concise and effective transitions. Furthermore, our research offers intriguing insights about the potential mitigation of visual incoherence between virtual and augmented reality environments by utilizing different transitions.
Using augmented reality in education is already a common concept, as it has the potential to turn learning into a motivational learning experience. However, current research only covers the students ...site of learning. Almost no research focuses on the teachers' site and whether augmented reality could potentially improve his/her workflow of teaching the students or not. Many researchers do not differentiate between multiple user roles, like a student and a teacher. To allow investigation into these lacks of research, a teaching system "Augmentix" is presented, which includes a differentiation between the two user roles "teacher" and "student" to potentially enhances the teachers workflow by using augmented reality. In this system's setting the student can explore a virtual city in virtual reality and the teacher can guide him with augmented reality.
Augmented and virtual reality have the potential to improve various aspects of everyday life such as tourism. An elementary part of tourism is the organization and execution of guided city tours. In ...case of tours for virtual cities, such as in the case of no longer existing ancient settlements, a combination of augmented and virtual reality may render high benefit for collaboration between guide and visitors. Immersive technology has been shown suitable for collaborative systems by previous research, as they can provide a better experience than other technologies. However, recent literature analyses showed that there is a lack of research regarding the role of augmented reality supporting the active/leading user role in such scenarios. Usually, augmented reality is used for the users who are passively experiencing the virtual environment and not for the one controlling it. However, we think that augmented reality has a large potential to improve the workflow of such a primary user. To investigate this research question, we present a collaborative system in this work, which implements a virtual city tour. In this system, the guide is using augmented reality and the visitor is immersed in the virtual city using virtual reality glasses. To implement a valid research prototype, the system has been developed in close feedback with experts in the field of guided city tours.
A major challenge in augmented reality applications is the occlusion of virtual objects by physical, real-world objects. Occlusion, however, is a major cue for perceiving the correct depth of objects ...and whether those are colliding or not. Obtaining an accurate depth perception is especially important for mid-air interactions since misperception can result in low usability. To investigate the effect of hand occlusion in radial mid-air menu interaction, we implemented a model-based method for hand occlusion and conducted a user study (N = 30) where basic mid-air interactions had to be performed with and without occlusion. Further, we were interested in investigating whether the effect of occlusion additionally depends on the interaction method used for the radial mid-air menu interaction, namely pinching or tapping. Contrary to our expectations, our results indicate both positive and negative effects occlusion for the interaction methods on usability. We identify and discuss possible side effects that could have led to these unexpected results.
This tech demo offers an immersive exploration of the most promi-nent scene transitions within the Reality-Virtuality Continuum (RVC). It delves into the seamless integration of real and virtual ...worlds, showcasing a spectrum of environments ranging from entirely real to fully virtual and various transitions to switch between them. Our innovative approach centers around an engaging cross-environmental spatial memory game. This game is not just a playful experience but a carefully crafted task designed to challenge users. As players navigate through different environments via transitions, they encounter different object categories and a dynamic scoring system. Previous studies have explored transitioning between stages like augmented reality (AR) and virtual reality (VR), but our work integrates these technologies into a demanding, interactive task. This integration allows for a nuanced examination of six types of transitions, ranging from diegetic to disruptive. Our demo is not just a showcase; it is a step forward in understanding and optimizing cross-reality applications. It offers a fresh perspective on RVC transitions and paves the way for future research into enhancing user experience in mixed-reality environments. A video of this tech demo can be found here: https://www.youtube.com/watch?v=o46r4QdUNgg
The impact of different transitions between two virtual reality (VR) environments is still an open research question, and related work often serves only an isolated view on different techniques, ...i.e., with low ecological validity. The purpose of this study was to start closing this gap and evaluate the impact of six transitions while the user is solving a task that keeps them engaged. Therefore, we first propose a suitable and reproducible task design. Then we evaluate the six transitions in a user study. The results show that in contrast to prior work, the users preferred a short and efficient transition against a transition that was designed to achieve higher interactivity and continuity but was perceived as more cumbersome to use.
To date, micropollutants from anthropogenic sources cannot be completely removed from effluents of wastewater treatment plants and therefore enter freshwater systems, where they may impose adverse ...effects on aquatic organisms, for example, on fish. Advanced treatment such as ozonation aims to reduce micropollutants in wastewater effluents and, thus, to mitigate adverse effects on the environment. To investigate the impact and efficiency of ozonation, four different water types were tested: ozonated wastewater (before and after biological treatment), conventionally-treated wastewater, and water from a river (River Ruhr, Germany) upstream of the wastewater treatment plant effluent. Zebrafish (Danio rerio) embryos were used to study lethal and sublethal effects in a modified fish early life-stage test. Mortality occurred during exposure in the water samples from the wastewater treatment plant and the river in the first 24 h post-fertilization, ranging from 12% (conventional wastewater) to 40% (river water). Regarding sublethal endpoints, effects compared to the negative control resulted in significantly higher heart rates (ozonated wastewater), and significantly reduced swimming activity (highly significant in ozonated wastewater and ozone reactor water, significant in only the last time interval in river water). Moreover, the respiration rates were highly increased in both ozonated wastewater samples in comparison to the negative control. Significant differences between the ozonated wastewater samples occurred in the embryonic behavior and heart rates, emphasizing the importance of subsequent biological treatment of the ozonated wastewater. Only the conventionally-treated wastewater sample did not elicit negative responses in zebrafish, indicating that the discharge of conventional wastewater poses no greater risk to embryonic and larval zebrafish than water from the river Ruhr itself. The sublethal endpoints embryonic- and larval behavior, heart rates, and respiration were found to be the most sensitive endpoints in this fish early life-stage test and can add valuable information on the toxicity of environmental samples.
Display omitted
•Conventionally-treated wastewater showed no adverse effects on Danio rerio.•No detoxification effect of wastewater following ozonation was detected.•Background toxicity in the river should be considered when evaluating WWTP effluents.•Sublethal effects are the most sensitive endpoints in the fish early life-stage test.
Scope
Acrolein (AC) and acrylamide (AA) are food contaminants generated by heat treatment. We studied human exposure after consumption of potato crisps by monitoring excretion of mercapturic acids ...(MAs) in urine.
Methods and results
MA excretion was monitored in human urine collected up to 72 h after ingestion of a test meal of experimental (study 1: 1 mg AA/150 g) or commercially available (study 2: 44 μg AA plus 4.6 μg AC/175 g) potato crisps. MA contents were analysed after purification via SPE using HPLC‐ESI‐MS/MS. On the basis of the area under the curve values of MAs excreted in urine, the total excretion of AC‐related MAs exceeded that of AA‐related MAs up to 12 times in study 1 and up to four times in study 2. Remarkably, AC content of potato crisps of study 2 was found to be only about 1/10 the AA content, as determined by isotope dilution headspace GC/MS.
Conclusion
Our results indicate substantially higher exposure to AC from potato crisps than to AA. Total AC in such foods may encompass bioavailable AC forms not detected by headspace GC/MS. Both findings may also apply to other heat processed foods.
Acrylamide (AA) is formed during the heating of food and is classified as a genotoxic carcinogen. The margin of exposure (MOE), representing the distance between the bench mark dose associated with ...10% tumor incidence in rats and the estimated average human exposure, is considered to be of concern. After ingestion, AA is converted by P450 into the genotoxic epoxide glycidamide (GA). GA forms DNA adducts, primarily at N7 of guanine (N7-GA-Gua). We performed a dose–response study with AA in female Sprague–Dawley (SD) rats. AA was given orally in a single dosage of 0.1–10 000 μg/kg bw. The formation of urinary mercapturic acids and of N7-GA-Gua DNA adducts in liver, kidney, and lung was measured 16 h after application. A mean of 37.0 ± 11.5% of a given AA dose was found as mercapturic acids (MAs) in urine. MA excretion in urine of untreated controls indicated some background exposure from endogenous AA. N7-GA-Gua adduct formation was not detectable in any organ tested at 0.1 μg AA/kg bw. At a dose of 1 μg/kg bw, adducts were found in kidney (around 1 adduct/108 nucleotides) and lung (below 1 adduct/108 nucleotides) but not in liver. At 10, respectively, 100 μg/kg bw, adducts were found in all three organs, at levels close to those found at 1 μg AA/kg, covering a range of about 1–2 adducts/108 nucleotides. As compared to DNA adduct levels from electrophilic genotoxic agents of various origin found in human tissues, N7-GA-Gua adduct levels within the dose range of 0.1–100 μg AA/kg bw were at the low end of this human background. We propose to take the background level of DNA lesions in humans more into consideration when doing risk assessment of food-borne genotoxic carcinogens.
