Media Presence and Inner Presence: The Sense of Presence in Virtual Reality Technologies

Abstract. Presence is widely accepted as the key concept to be considered in any research involving human interaction with Virtual Reality (VR). Since its original description, the concept of presence has developed over the past decade to be considered by many researchers as the essence of any experience in a virtual environment. The VR generating systems comprise two main parts: a technological component and a psychological experience. The different relevance given to them produced two different but coexisting visions of presence: the rationalist and the psychological/ecological points of view. The rationalist point of view considers a VR system as a collection of specific machines with the necessity of the inclusion \ud of the concept of presence. The researchers agreeing with this approach describe the sense of presence as a function of the experience of a given medium (Media Presence). The main result of this approach is the definition of presence as the perceptual illusion of non-mediation produced by means of the disappearance of the medium from the conscious attention of the subject. At the other extreme, there \ud is the psychological or ecological perspective (Inner Presence). Specifically, this perspective considers presence as a neuropsychological phenomenon, evolved from the interplay of our biological and cultural inheritance, whose goal is the control of the human activity. \ud Given its key role and the rate at which new approaches to understanding and examining presence are appearing, this chapter draws together current research on presence to provide an up to date overview of the most widely accepted approaches to its understanding and measurement

Experimental evidence for the interplay between individual wealth and transaction network

We conduct a market experiment with human agents in order to explore the structure of transaction networks and to study the dynamics of wealth accumulation. The experiment is carried out on our platform for 97 days with 2,095 effective participants and 16,936 times of transactions. From these data, the hybrid distribution (log-normal bulk and power-law tail) in the wealth is observed and we demonstrate that the transaction networks in our market are always scale-free and disassortative even for those with the size of the order of few hundred. We further discover that the individual wealth is correlated with its degree by a power-law function which allows us to relate the exponent of the transaction network degree distribution to the Pareto index in wealth distribution.Comment: 6 pages, 7 figure

Future studies in Brazil:CGEE approach for bio- and nanotechnology

Companies and governments are increasingly using "Future Studies" for the design of their strategic planning. Techniques and methodologies are in very accelerated development all over the world. So it is necessary to establish the right set of tools and best way to use it in order to have results that you could compare and reproduce if you have in mimd to generate inputs for either companies or countries policy definition. This article describes the methodological approach adopted by a Brazilian Institution - Centre for Strategic Management and Studies - CGEE, mainly devoted to future analyses, and uses the recent examples of the Biotechnology and Nanotechnology foresight exercises in Brazil to show the real use of their results in the process for definition of national strategies

Is upper gastrointestinal radiography a cost-effective alternative to a Helicobacter pylori “Test and Treat” strategy for patients with suspected peptic ulcer disease?

Current clinical consensus supports an initial Helicobacter pylori (HP) “test and treat” approach when compared to immediate endoscopy for patients with suspected peptic ulcer disease. Alternative diagnostic approaches that incorporate upper GI radiography (UGI) have not been previously evaluated. We sought to determine the cost effectiveness of UGI compared to a HP test and treat strategy, incorporating recent data addressing the reduced prevalence of HP, lower cost of diagnostic interventions, and reduced attribution of PUD to HP. METHODS : Using decision analysis, three diagnostic and treatment strategies were evaluated: 1) Test and Treat —initial HP serology, treat patients who test positive with HP eradication and antiulcer therapy; 2) Initial UGI series —treat all patients with documented ulcer disease with HP eradication and antiulcer therapy; and 3) Initial UGI series, HP serology if ulcer present — treat ulcer and HP based on diagnostic test results. RESULTS : The estimated cost per ulcer cured for each strategy were as follows: test and treat, $3,025; initial UGI,$3,690; and UGI with serology, $3,790. The estimated cost per patient treatment were: test and treat,$498; initial UGI, $610; and UGI with serology,$620. When UGI reimbursement was decreased to less than $50, the UGI strategies yielded a lower cost per patient treated than the test and treat strategy. CONCLUSION : At the current level of reimbursement, UGI should not be considered a cost-effective alternative to the HP test and treat strategy for the initial evaluation of patients with suspected peptic ulcer disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73722/1/j.1572-0241.2000.01837.x.pd

Human toxocariasis: contribution by Brazilian researchers

In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT)