A prevailing argument posits that distal landmarks dominate over proximal landmarks as orientation cues. However, no studies have tested this argument or examined the underlying mechanisms. This ...project aimed to close this gap by examining the roles of relative cue precision and prior knowledge in cue preference. Participants learned object locations with proximal and distal landmarks in an immersive virtual environment. After walking a path without seeing objects or landmarks, participants disoriented themselves by spinning in place and pointed to the objects with the reappearance of a proximal landmark being rotated −50°, a distal landmark being rotated 50°, or both (Conflict). Heading errors were examined. Experiment 1 manipulated the relative cue precision. Results showed that in Conflict condition, the observed weight on the distal cue (exceeding 0.5) changed with but remained higher than the weight predicted by the relative cue precision. This indicates that besides the relative cue precision, prior knowledge of distal cue dominance also influences orientation cue usage. In Experiments 2 and 3, participants walked a path stopping at one object location. Participants were informed of it explicitly in Experiment 2 but not in Experiment 3. Results showed that distal cue dominance still occurred in Experiment 3. However, in Experiment 2, proximal cue dominance appeared, and it was not predicted by the relative cue precision. These results suggest that prior knowledge of proximal cue dominance might have been invoked by the instruction of locations. Consistent with the Bayesian inference model, human cue usage in orientation is determined by relative cue precision and prior knowledge. The choice of prior knowledge can be influenced by instructions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Crystallographic texture of alloy can trigger anisotropic properties, which have been studied extensively. However, the effect of spatial orientation of grains on the mechanical properties, ...especially for additive manufactured metals with lamellar morphology has remained elusive. Herein, this work theoretically calculated the spatial and crystallographic orientations of α lath from the β//Z-axis (build direction) fiber texture, and investigate the relationship between the orientations of α lath and the deformation behaviors and mechanical properties of the Ti–6Al–4V alloy built via electron beam directed energy deposition (EB DED). Deformation features display the prismatic slip system of α lath that exists a smaller angle to the broad face of α lath showing a lower effective critical resolved shear stress (CRSS). This is because this prismatic slip system has a greater slip range when compares with other slip systems. Such deformation features, combined with the spatial orientation distribution characteristic of α lath that is induced by the β//Z-axis fiber texture, lead to strongly tensile anisotropy, specifically, the samples oriented 45° and 67.5° angles to z-axis present greater strengths but lower ductility, whereas the sample in the z-axis direction generally displays a minimum strength but a superb ductility. This finding is vital for providing an important theoretical basis for optimizing the consistency of mechanical properties of the additive manufactured α+β dual phase titanium alloy.
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IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Spatial orientation is a complex ability that emerges from the interaction of several systems in a way that is still unclear. One of the reasons limiting the research on the topic is the lack of ...methodologies aimed at studying multimodal psychophysics in an ecological manner and with affordable settings. Virtual reality can provide a workaround to this impasse by using virtual stimuli rather than real ones. However, the available virtual reality development platforms are not meant for psychophysical testing; therefore, using them as such can be very difficult for newcomers, especially the ones new to coding. For this reason, we developed SALLO, the Suite for the Assessment of Low-Level cues on Orientation, which is a suite of utilities that simplifies assessing the psychophysics of multimodal spatial orientation in virtual reality. The tools in it cover all the fundamental steps to design a psychophysical experiment. Plus, dedicated tracks guide the users in extending the suite components to simplify developing new experiments. An experimental use-case used SALLO and virtual reality to show that the head posture affects both the egocentric and the allocentric mental representations of spatial orientation. Such a use-case demonstrated how SALLO and virtual reality can be used to accelerate hypothesis testing concerning the psychophysics of spatial orientation and, more broadly, how the community of researchers in the field may benefit from such a tool to carry out their investigations.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Various viewing and travel techniques are used in immersive virtual reality to allow users to see different areas or perspectives of 3D environments. Our research evaluates techniques for visually ...showing transitions between two viewpoints in head-tracked virtual reality. We present four experiments that focus on automated viewpoint changes that are controlled by the system rather than by interactive user control. The experiments evaluate three different transition techniques ( teleportation , animated interpolation , and pulsed interpolation ), different types of visual adjustments for each technique, and different types of viewpoint changes. We evaluated how differences in transition can influence a viewer's comfort, sickness, and ability to maintain spatial awareness of dynamic objects in a virtual scene. For instant teleportations, the experiments found participants could most easily track scene changes with rotational transitions without translational movements. Among the tested techniques, animated interpolations allowed significantly better spatial awareness of moving objects, but the animated technique was also rated worst in terms of sickness, particularly for rotational viewpoint changes. Across techniques, viewpoint transitions involving both translational and rotational changes together were more difficult to track than either individual type of change.
Successful navigation depends critically upon two broad categories of spatial navigation strategies that include allocentric and egocentric reference frames, relying on external or internal spatial ...information, respectively. As with older adults, aged rats show robust impairments on a number of different spatial navigation tasks. There is some evidence that these navigation impairments are accompanied by a bias toward relying on egocentric over allocentric navigation strategies. To test the degree to which young and aged animals utilize these two navigation approaches, a novel behavioral arena was used in which rats are trained to traverse a circular track and to stop at a learned goal location that is fixed with respect to a panorama of visual cues projected onto the surrounding walls. By instantaneously rotating the cues, allocentric and egocentric reference frames were put in direct and immediate conflict and goal navigation performance was assessed with respect to how accurately young and aged animals were able to utilize the rotated cues. Behavioral data collected from nine young and eight aged animals revealed that both age groups were able to update their navigation performance following cue rotation. Contrary to what was expected, however, aged animals showed more accurate overall goal navigation performance, stronger allocentric strategy use, and more evident changes in behavior in response to cue rotation compared to younger animals. The young rats appeared to mix egocentric and allocentric strategies for ICR task solution.
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CEKLJ, FFLJ, NUK, ODKLJ, PEFLJ, UPUK
Despite the now-ubiquitous two-dimensional (2D) electronic maps, three-dimensional (3D) globe viewers, or 3D geo-browsers such as Google Earth and NASA World Wind have gained much attention. However, ...the effect of such interactive 3D geo-browsers on spatial knowledge acquisition and decision-making is not well known. This study aims to explore the potential benefits of using interactive 3D geo-browsers in three processes of pedestrian navigation (self-localization, spatial knowledge acquisition, and decision-making) in digital environments. We employed eye tracking to show differences of visual attention in pedestrian navigation between a 2D map (Google Map) and a 3D geo-browser (Google Earth). The results indicated that benefits and drawbacks of 3D representations are task dependent. Participants using the 3D geo-browser had an extensively visual search resulting in significantly longer response time than the 2D participants for spatial knowledge acquisition, whereas 3D users performed a more efficient visual search and resulted in a better navigation performance at complex decision points. We speculate that the inefficient knowledge acquisition when using the 3D geo-browser was most probably due to information overload and obstructed views. Landmarks in photorealistic 3D models assisted recall of spatial knowledge from mental maps, which contributed to efficient decision-making at a complex turning point. These empirical results can be helpful to improve the usability of pedestrian navigation systems.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The perceived offset of a moving target is usually displaced forward, in the direction of motion (representational momentum), and downward, in the direction of gravity (representational gravity). In ...what refers to the latter, the meaning of "downward in the direction of gravity" is ill-defined, for it is known that the perceived direction of gravity ("downward") results from the interaction of vestibular signals, sensitive to the gravito-inertial vector, an aprioristic tendency to assume that it aligns with the body's main axis (idiotropic vector) and visual cues. The present work aims to disclose what effects visual cues have on representational gravity. Participants performed a spatial localization task as well as a subjective visual vertical (SVV) and an oriented character recognition task (OCHART), with stimuli superimposed on a realistic background either aligned with earth's vertical or tilted rightward or leftward. Outcomes disclosed significant and lawful effects of the orientation of the visual context on spatial localization judgements. Specifically, forward displacement along the target's motion direction was bigger for targets moving along the "horizontal" direction implied by the background scene. These trends were furthermore found to be correlated, at an individual level, with the magnitude of SVV, but not with the perceptual upright (as measured with OCHART). These findings show that features of the spatial localization judgements specifically index the visually induced spatial orientation, thus offering the prospect to expand available tools for inquiries concerning human spatial orientation, besides clarifying the multisensorial nature and significantly expanding the notion of representational gravity.
Public Significance StatementThis study reveals that the orientation of the visual context affects the spatial localization of moving targets, in accordance with the hypothesized role of an internal model of gravity. The found outcomes, besides adding to the current knowledge on the visual representation of gravity and human spatial orientation, offer tentative prospects for clinical assessment tools and human factors insights.
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CEKLJ, FFLJ, NUK, ODKLJ, PEFLJ, UPUK
The central complex is a group of modular neuropils across the midline of the insect brain. Hallmarks of its anatomical organization are discrete layers, an organization into arrays of 16 slices ...along the right-left axis, and precise inter-hemispheric connections via chiasmata. The central complex is connected most prominently with the adjacent lateral complex and the superior protocerebrum. Its developmental appearance corresponds with the appearance of compound eyes and walking legs. Distinct dopaminergic neurons control various forms of arousal. Electrophysiological studies provide evidence for roles in polarized light vision, sky compass orientation, and integration of spatial information for locomotor control. Behavioral studies on mutant and transgenic flies indicate roles in spatial representation of visual cues, spatial visual memory, directional control of walking and flight, and place learning. The data suggest that spatial azimuthal directions (i.e., where) are represented in the slices, and cue information (i.e., what) are represented in different layers of the central complex.
Membrane separation technology has shown great potential in resource recovery, energy utilization, and environmental protection, attracting extensive attention for the various practical applications. ...The alginate-based hydrogel membrane, derived from natural biomass, possesses sustainability and anti-fouling properties, effectively reducing the burden of waste membrane disposal. However, the limitations of alginate hydrogel include its high swelling ability, low permeability, and poor mechanical properties. In this study, we propose a straightforward method to fabricate orderliness hydrogels by employing lanthanide ion via dual cross-linking with CaAlg, resulting in the formation of lanthanum calcium alginate (La-CaAlg) hydrogel membrane. The La-CaAlg membrane exhibits superior mechanical performance and anti-swelling properties compared to LaAlg and CaAlg membranes. Additionally, through small-angle scattering and low-field nuclear magnetic resonance studies on the membrane's spatial orientation, and pore size distribution, we gained the comparable results into its internal structure for the design insight. Notably, the La-CaAlg membrane demonstrates outstanding performance in dye/salt separation, showcasing high selectivity and permeability. We propose the strategy that enhances the orderliness and durability of the alginate hydrogel membrane, providing the separation design insight to overcome the limitations associated with the permeability and rejection trade-off.
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•The dual cross-linking strategy was proposed to adjust the structural orderliness.•La-CaAlg membrane exhibits excellent mechanical stability, anti-fouling characteristic, and anti-swelling properties.•La-CaAlg membrane offers valuable insights to overcome the limitations associated with the trade-off between permeability and rejection.•La-CaAlg membrane has outstanding dye/salt selectivity separation property.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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