Les interactions naturelles en réalité virtuelle : impact sur la charge cognitive

International audienceMany of the virtual reality (VR) interaction devices available to the general public rely on the use of controllers. However, theses ones generate some usability constraints. Current availability of new gestural devices provides a more “natural” way to interact in VR, i.e. more intuitive, facilitating learning and especially minimizing cognitive load. However, this last one is rarely taken into account in the literature on VR design and evaluation. In order to fill this gap, we propose to evaluate, within a comparative study, the respective impact of 2 interaction paradigms on the cognitive load and performance of two different user populations (experienced vs. novice): gestural interaction using Leap Motion® (test group) and more traditional interaction using gamepad controllers (control group). Initial results indicate significantly higher cognitive load and significantly lower performance during gestural interaction with the Leap Motion® than during interaction with the controllers. These results highlight technical limitations related to Leap Motion® and the need to improve technically these devices to obtain a robust technologyUne grande partie des dispositifs d’interaction en réalité virtuelle (VR) accessibles au grand public repose sur l’usage des contrôleurs. Or, ces derniers génèrent certaines contraintes d’utilisabilité. La récente disponibilité de dispositifs d’interaction gestuelle permet d’avoir des interactions plus « naturelles » pour l’utilisateur, i.e. plus intuitives, permettant de faciliter l’apprentissage et surtout de minimiser la charge cognitive; or ce dernier trait est peu pris en compte dans la littérature en conception/évaluation VR. Afin de pallier ce manque, nous proposons d’évaluer au sein d'une étude comparative, l’impact respectif de 2 paradigmes d’interaction sur la charge cognitive et les performances de deux populations d’utilisateurs différentes (expérimentée vs. novice) : les interactions gestuelles à l’aide du Leap Motion® (groupe test) et les interactions plus classiques à l’aide de contrôleurs de mouvement de type gamepad (groupe contrôle). Les premiers résultats indiquent une charge cognitive significativement plus élevée et des performances significativement moindres lors de l’interaction gestuelle avec le Leap Motion® que lors de l’interaction avec les contrôleurs et ce, pour les 2 types de population. Ces résultats mettent en évidence les limites techniques liées au Leap Motion® ainsi que la nécessité d’améliorer techniquement ces dispositifs avant de pouvoir aboutir à une technologie robuste

Using Market Forces for Social Good

The environment has traditionally been the domain of nonprofit organizations. For decades, nonprofit organizations have worked to reduce the negative impact of market-based activity on the environment. However, more recently nonprofits have started to adopt the methods and values of the market to achieve sustainability goals. One of the primary strategies that nonprofits use is to disclose, or pressure corporations to disclose, information about the environmental impact of their products and processes. These information disclosure strategies seek to help stakeholders make green purchases or invest in corporations that use green practices, thus incentivizing corporations to reduce their negative environmental impact. In this chapter, we review the benefits and the challenges encountered by nonprofits in their attempt to use information disclosure strategies

Interactions naturelles en réalité virtuelle~: impact sur la charge cognitive

National audienceMany of the virtual reality (VR) interaction devices available to the general public rely on the use of controllers. However, theses ones generate some usability constraints. Current availability of new gestural devices provides a more "natural" way to interact in VR, i.e. more intuitive, facilitating learning and especially minimizing cognitive load. However, this last one is rarely taken into account in the literature on VR design and evaluation. In order to fill this gap, we propose to evaluate, within a comparative study, the respective impact of 2 interaction paradigms on the cognitive load and performance of two different user populations (experienced vs. novice): gestural interaction using Leap Motion\textregistered (test group) and more traditional interaction using gamepad controllers (control group). Initial results indicate significantly higher cognitive load and significantly lower performance during gestural interaction with the Leap Motion\textregistered than during interaction with the controllers. These results highlight technical limitations related to Leap Motion\textregistered and the need to improve technically these devices to obtain a robust technology.Une grande partie des dispositifs d'interaction en réalité virtuelle (VR) accessibles au grand public repose sur l'usage des contrôleurs. Or, ces derniers génèrent certaines contraintes d'utilisabilité. La récente disponibilité de dispositifs d'interaction gestuelle permet d'avoir des interactions plus " naturelles " pour l'utilisateur, c'est-à-dire plus intuitives, permettant de faciliter l'apprentissage et surtout de minimiser la charge cognitive ; or ce dernier trait est peu pris en compte dans la littérature en conception/évaluation VR. Afin de pallier ce manque, nous proposons d'évaluer au sein d'une étude comparative, l'impact respectif de 2 paradigmes d'interaction sur la charge cognitive et les performances de deux populations d'utilisateurs différentes (expérimentée vs. novice)~: les interactions gestuelles à l'aide du Leap Motion\textregistered (groupe test) et les interactions plus classiques à l'aide de contrôleurs de mouvement de type gamepad (groupe contrôle). Les premiers résultats indiquent une charge cognitive significativement plus élevée et des performances significativement moindres lors de l'interaction gestuelle avec le Leap Motion\textregistered que lors de l'interaction avec les contrôleurs et ce, pour les 2 types de population. Ces résultats mettent en évidence les limites techniques liées au Leap Motion\textregistered ainsi que la nécessité d'améliorer techniquement ces dispositifs avant de pouvoir aboutir à une technologie robuste

Strontium ranelate and alendronate have differing effects on distal tibia bone microstructure in women with osteoporosis

The structural basis of the antifracture efficacy of strontium ranelate and alendronate is incompletely understood. We compared the effects of strontium ranelate and alendronate on distal tibia microstructure over 2years using HR-pQCT. In this pre-planned, interim, intention-to-treat analysis at 12months, 88 osteoporotic postmenopausal women (mean age 63.7±7.4) were randomized to strontium ranelate 2g/day or alendronate 70mg/week in a double-placebo design. Primary endpoints were changes in microstructure. Secondary endpoints included lumbar and hip areal bone mineral density (aBMD), and bone turnover markers. This trial is registered with http://www.controlled-trials.com, number ISRCTN82719233. Baseline characteristics of the two groups were similar. Treatment with strontium ranelate was associated with increases in mean cortical thickness (CTh, 5.3%), cortical area (4.9%) and trabecular density (2.1%) (all P<0.001, except cortical area P=0.013). No significant changes were observed with alendronate. Between-group differences in favor of strontium ranelate were observed for CTh, cortical area, BV/TV and trabecular density (P=0.045, 0.041, 0.048 and 0.035, respectively). aBMD increased to a similar extent with strontium ranelate and alendronate at the spine (5.7% versus 5.1%, respectively) and total hip (3.3% versus 2.2%, respectively). No significant changes were observed in remodeling markers with strontium ranelate, while suppression was observed with alendronate. Within the methodological constraints of HR-pQCT through its possible sensitivity to X-ray attenuation of different minerals, strontium ranelate had greater effects than alendronate on distal tibia cortical thickness and trabecular volumetric densit

Placing taxonomists at the heart of a definitive and comprehensive global resource on the world's plants

It is time to synthesize the knowledge that has been generated through more than 260 years of botanical exploration, taxonomic and, more recently, phylogenetic research throughout the world. The adoption of an updated Global Strategy for Plant Conservation (GSPC) in 2011 provided the essential impetus for the development of the World Flora Online (WFO) project. The project represents an international, coordinated effort by the botanical community to achieve GSPC Target 1, an electronic Flora of all plants. It will be a first‐ever unique and authoritative global source of information on the world's plant diversity, compiled, curated, moderated and updated by an expert and specialist‐based community (Taxonomic Expert Networks – “TENs” – covering a taxonomic group such as family or order) and actively managed by those who have compiled and contributed the data it includes. Full credit and acknowledgement will be given to the original sources, allowing users to refer back to the primary data. A strength of the project is that it is led and endorsed by a global consortium of more than 40 leading botanical institutions worldwide. A first milestone for producing the World Flora Online is to be accomplished by the end of 2020, but the WFO Consortium is committed to continuing the WFO programme beyond 2020 when it will develop its full impact as the authoritative source of information on the world's plant biodiversity

Innovation in tourism: Re-conceptualising and measuring the absorptive capacity of the hotel sector

Recent reviews of research on innovation in tourism have highlighted a number of weaknesses in the literature. Among these is the limited theorising and empirical investigation of innovative practices by tourism organisations. This paper responds to these concerns by examining one important dimension of innovation within commercial tourism organisations, namely their ability to acquire, assimilate and utilise external knowledge (absorptive capacity) for competitive advantage. The topic is pertinent because there is evidence to suggest that tourism organisations are particularly dependent on external sources of knowledge when compared with businesses in other sectors. Following a discussion of the conceptual antecedents of absorptive capacity and its dimensions, a validated instrument for its measurement is developed and used to measure the absorptive capacity of the British hotel sector. The results suggest that current conceptions of absorptive capacity have limitations when applied to tourism enterprises. Absorptive capacity is re-conceptualised to overcome these deficiencies. The research and policy implications of the findings are discussed. © 2014 Elsevier Ltd

The Impact of Indirect Corporate Social Performance Signals on Firm Value: Evidence from an Event Study

Prior research shows that signals sent by institutionalized third parties (i.e. indirect signals) about firms' corporate social performance (CSP) can impact firm value. However, the effects that different types of indirect CSP signals have on firm value have remained largely unexplored. Furthermore, managers often do not fully understand how to communicate CSP effectively. In this article, we operationalize CSP as a multidimensional construct and draw on signalling theory to examine how different types of indirect CSP signals impact firm value. The results of an event study show that institutionalized third parties can play an important role in delivering credible CSP‐related information to the market. Results also demonstrate that the valence (positivity vs. negativity) and content (the specific social domain) of indirect CSP signals are important predictors of the magnitude of market reactions, and that shareholders' responses to the valence and content of indirect CSP signals have substantially changed over time

Refocusing multiple stressor research around the targets and scales of ecological impacts

Ecological communities face a variety of environmental and anthropogenic stressors acting simultaneously. Stressor impacts can combine additively or can interact, causing synergistic or antagonistic effects. Our knowledge of when and how interactions arise is limited, as most models and experiments only consider the effect of a small number of non-interacting stressors at one or few scales of ecological organization. This is concerning because it could lead to significant underestimations or overestimations of threats to biodiversity. Furthermore, stressors have been largely classified by their source rather than by the mechanisms and ecological scales at which they act (the target). Here, we argue, first, that a more nuanced classification of stressors by target and ecological scale can generate valuable new insights and hypotheses about stressor interactions. Second, that the predictability of multiple stressor effects, and consistent patterns in their impacts, can be evaluated by examining the distribution of stressor effects across targets and ecological scales. Third, that a variety of existing mechanistic and statistical modelling tools can play an important role in our framework and advance multiple stressor research