How to Get There When You Are There Already? Defining Presence in Virtual Reality and the Importance of Perceived Realism

The aim of the current opinion paper is to challenge the current definition of presence in the context of virtual reality (VR). Opticians do not only measure visual acuity but also the visual field, stereoscopic vision, and color vision. In the same vein, presence researchers are encouraged to not only measure the experience of “being there” in the sense of attentional allocation to the virtual environment (VE), but also the perceived realism of the VE. Perceived realism is the result of an evaluation of the virtual world regarding (1) the subjective degree of reality of the depicted environment and (2) its overall plausibility and credibility. Thus, the sense of presence in a VE is conceived as a composite of being there and perceived realism. When in VR, a user will inevitably compare the look of virtual objects to real-world objects and judge the level of congruence (Sutcliffe and Gault, 2004). The user evaluates the plausibility and naturalness of the depicted world as well as the ease of interaction within the VE by answering questions such as: is there a shadow cast? Are the proportions of objects correct? Does the environment correspond to my own movements? Does my virtual body match the proportions of my real body? Just like the visual features, a story and its characters are also evaluated in terms of consistency and plausibility (Park et al., 2010; Gorini et al., 2011): are the consequences of actions plausible? Is the story coherent in itself? Does the causal sequence of events make sense? The answers to these questions define the degree of perceived realism. Perceived realism leads to the experience that a user not only feels surrounded by the VE, but rather has a compelling sense of reality and in extreme cases even forgets that he or she is wearing a head-mounted display (HMD). Previous papers on presence are based on the assumption that realism enhances presence (e.g., Heeter, 1992; Welch et al., 1996; Lombard and Ditton, 1997; Bystrom et al., 1999) suggested a conceptualization of presence as the degree to which a medium seems realistic. Interestingly, perceived realism is nevertheless not part of the most widely used presence definitions. It is either a possible trigger of presence or is blended in with the term being there. The conceptualization of presence as the experience of being there in a mediated environment dominates current presence definitions. Being there is strongly associated with attentional allocation and the sensation of being surrounded and absorbed by a mediated world. However, we claim that presence in VR requires much more than just being there. With the widespread use of immersive VR technology, it has become an easy task to absorb users in a VE. Thus, judgments about the realism of the VE become increasingly important. Being there and perceived realism are both important but yet different aspects of presence. They need to be combined in order to (1) adequately describe and define the experience of presence and (2) to obtain an appropriate and more complete assessment of presence in VR. Thus, theories and measures of presence need to be extended and establish perceived realism as an important domain besides being there. Presence in VR as a Two-Dimen

No association of a set of candidate genes on haloperidol side effects.

We previously investigated a sample of patients during an active phase of psychosis in the search for genetic predictors of haloperidol induced side effects. In the present work we extend the genetic association analysis to a wider panel of genetic variations, including 508 variations located in 96 genes. The original sample included 96 patients. An independent group of 357 patients from the CATIE study served as a replication sample. Outcomes in the investigation sample were the variation through time of: 1) the ESRS and UKU total scores 2) ESRS and UKU subscales (neurologic and psychic were included) related to tremors and 3) ESRS and UKU subscales that do not relate to tremors. Outcome in the replication sample was the presence vs absence of motoric side effects from baseline to visit 1 (~ one month of treatment) as assessed by the AIMS scale test. Rs2242480 located in the CYP3A4 was associated with a different distribution of the UKU neurologic scores through time (permutated p = 0.047) along with a trend for a different haloperidol plasma levels (lower in CC subjects). This finding was not replicated in the CATIE sample. In conclusion, we did not find conclusive evidence for a major association between the investigated variations and haloperidol induced motoric side effects

Periodic Mean-Field Solutions and the Spectra of Discrete Bosonic Fields: Trace Formula for Bose-Hubbard Models

We consider the many-body spectra of interacting bosonic quantum fields on a lattice in the semiclassical limit of large particle number $N$. We show that the many-body density of states can be expressed as a coherent sum over oscillating long-wavelength contributions given by periodic, non-perturbative solutions of the, typically non-linear, wave equation of the classical (mean-field) limit. To this end we construct the semiclassical approximation for both the smooth and oscillatory part of the many-body density of states in terms of a trace formula starting from the exact path integral form of the propagator between many-body quadrature states. We therefore avoid the use of a complexified classical limit characteristic of the coherent state representation. While quantum effects like vacuum fluctuations and gauge invariance are exactly accounted for, our semiclassical approach captures quantum interference and therefore is valid well beyond the Ehrenfest time where naive quantum-classical correspondence breaks down. Remarkably, due to a special feature of harmonic systems with incommesurable frequencies, our formulas are generically valid also in the free-field case of non-interacting bosons.Comment: submitted to Phys. Rev.

The Development Of Mutual Trust In British Workplaces Through ?Partnership?

This article examines the alleged links between 'partnership' forms ofmanaging workplace relationships in Britain, and the development ofintra-organisational 'trust'. The potential for mutually complementarylinkages between the two are clear, in theory at least: partnership,as defined here, should produce, nurture and enhance levels ofinterpersonal trust inside organisations, while in turn trust, asdefined here, legitimates and helps reinforce an organisation's'partnership'. Qualitative evidence drawn from the self-reports of keyparticipants in four partnership organisations provides considerablesupport for the claimed linkages, while also highlighting severalweaknesses, discrepancies and pitfalls inherent in the process ofpursuing trust through partnership. This research is of interest froma public policy perspective, most of all in the United Kingdom, wherepartnership is the favoured organisational model for the New Labourgovernment, most trade unions, and many employers (not to mention theEuropean Union) yet where an agreed definition of the idea has yet toemerge, and where still remarkably little is known about whatpartnership involves inside organisations. This analysis also seeks torestore the curiously neglected idea of trust to a position of centralimportance to the study of employment relations.United Kingdom;case studies;organisational change;trust;social partnership