Virtual reality at work

The utility of virtual reality computer graphics in telepresence applications is not hard to grasp and promises to be great. When the virtual world is entirely synthetic, as opposed to real but remote, the utility is harder to establish. Vehicle simulators for aircraft, vessels, and motor vehicles are proving their worth every day. Entertainment applications such as Disney World's StarTours are technologically elegant, good fun, and economically viable. Nevertheless, some of us have no real desire to spend our lifework serving the entertainment craze of our sick culture; we want to see this exciting technology put to work in medicine and science. The topics covered include the following: testing a force display for scientific visualization -- molecular docking; and testing a head-mounted display for scientific and medical visualization

Common Stock Price Effects of Security Issues Conditioned by Current Earnings and Dividend Announcements

The valuation effect of debt and equity issue announcements on stock price varies predictably with the timing of earnings and dividend reports. Issue announcements closely preceding current cash flow signals have more negative valuation effects. Straight debt announcements also have a significantly negative effect on stock price when the offer announcement closely precedes earnings and dividend releases. The evidence is consistent with a separating equilibrium where better performing firms signal superior value by announcing equity offers shortly after dividend announcements. Poorer performers appear to time equity offers just before dividend signals, which in turn are more likely to be negative

Scene-motion thresholds during head yaw for immersive virtual environments

In order to better understand how scene motion is perceived in immersive virtual environments, we measured scene-motion thresholds under different conditions across three experiments. Thresholds were measured during quasi-sinusoidal head yaw, single left-to-right or right-to-left head yaw, different phases of head yaw, slow to fast head yaw, scene motion relative to head yaw, and two scene illumination levels. We found that across various conditions 1) thresholds are greater when the scene moves with head yaw (corresponding to gain 1:0), and 2) thresholds increase as head motion increases

Effects of Handling Real Objects and Self-Avatar Fidelity on Cognitive Task Performance and Sense of Presence in Virtual Environments

Immersive virtual environments (VEs) provide participants with computer-generated environments filled with virtual objects to assist in learning, training, and practicing dangerous and/or expensive tasks. But does having every object being virtual inhibit the interactivity and effectiveness for certain tasks? Further, does the visual fidelity of the virtual objects affect performance? If participants spent most of their time and cognitive load on learning and adapting to interacting with a purely virtual system, this could reduce the overall effectiveness of a VE. We conducted a study that investigated how handling real objects and self-avatar visual fidelity affects performance on a spatial cognitive manual task. We compared participants' performance of a block arrangement task in both a real-space environment and several virtual and hybrid environments. The results showed that manipulating real objects in a VE brings task performance closer to that of real space, compared to manipulating virtual objects

Towards a theory of conceptual design for software

Concepts are the building blocks of software systems. They are not just subjective mental constructs, but are objective features of a system's design: increments of functionality that were consciously introduced by a designer to serve particular purposes. This essay argues for viewing the design of software in terms of concepts, with their invention (or adoption) and refinement as the central activity of software design. A family of products can be characterized by arranging concepts in a dependence graph from which coherent concept subsets can be extracted. Just as bugs can be found in the code of a function prior to testing by reviewing the programmer's argument for its correctness, so flaws can be found in a software design by reviewing an argument by the designer. This argument consists of providing, for each concept, a single compelling purpose, and demonstrating how the concept fulfills the purpose with an archetypal scenario called an 'operational principle'. Some simple conditions (primarily in the relationship between concepts and their purposes) can then be applied to reveal flaws in the conceptual design.SUTD-MIT International Design Centre (IDC

Survival from XDR-TB Is Associated with Modifiable Clinical Characteristics in Rural South Africa

Drug-resistant tuberculosis (TB) is a major threat to global public health. Patients with extensively drug-resistant TB (XDR-TB), particularly those with HIV-coinfection, experience high and accelerated mortality with limited available interventions. To determine modifiable factors associated with survival, we evaluated XDR-TB patients from a community-based hospital in rural South Africa where a large number of XDR-TB cases were first detected.A retrospective case control study was conducted of XDR-TB patients diagnosed from 2005-2008. Survivors, those alive at 180 days from diagnostic sputum collection date, were compared with controls who died within 180 days. Clinical, laboratory and microbiological correlates of survival were assessed in 69 survivors (median survival 565 days [IQR 384-774] and 73 non-survivors (median survival 34 days [IQR 18-90]). Among 129 HIV+ patients, multivariate analyses of modifiable factors demonstrated that negative AFB smear (AOR 8.4, CI 1.84-38.21), a lower laboratory index of routine laboratory findings (AOR 0.48, CI 0.22-1.02), CD4>200 cells/mm(3) (AOR 11.53, 1.1-119.32), and receipt of antiretroviral therapy (AOR 20.9, CI 1.16-376.83) were independently associated with survival from XDR-TB.Survival from XDR-TB with HIV-coinfection is associated with less advanced stages of both diseases at time of diagnosis, absence of laboratory markers indicative of multiorgan dysfunction, and provision of antiretroviral therapy. Survival can be increased by addressing these modifiable risk factors through policy changes and improved clinical management. Health planners and clinicians should develop programmes focusing on earlier case finding and integration of HIV and drug-resistant TB diagnostic, therapeutic, and preventive activities

The Integrated Virtual Environment Rehabilitation Treadmill System

Slow gait speed and interlimb asymmetry are prevalent in a variety of disorders. Current approaches to locomotor retraining emphasize the need for appropriate feedback during intensive, task-specific practice. This paper describes the design and feasibility testing of the integrated virtual environment rehabilitation treadmill (IVERT) system intended to provide real-time, intuitive feedback regarding gait speed and asymmetry during training. The IVERT system integrates an instrumented, split-belt treadmill with a front-projection, immersive virtual environment. The novel adaptive control system uses only ground reaction force data from the treadmill to continuously update the speeds of the two treadmill belts independently, as well as to control the speed and heading in the virtual environment in real time. Feedback regarding gait asymmetry is presented 1) visually as walking a curved trajectory through the virtual environment and 2) proprioceptively in the form of different belt speeds on the split-belt treadmill. A feasibility study involving five individuals with asymmetric gait found that these individuals could effectively control the speed of locomotion and perceive gait asymmetry during the training session. Although minimal changes in overground gait symmetry were observed immediately following a single training session, further studies should be done to determine the IVERT’s potential as a tool for rehabilitation of asymmetric gait by providing patients with congruent visual and proprioceptive feedback

Hydraulic redistribution by two semi-arid shrub species: Implications for Sahelian agro-ecosystems

Hydraulic redistribution is the process of passive water movement from deeper moist soil to shallower dry soil layers using plant roots as conduits. Results from this study indicate that this phenomenon exists among two shrub species (Guiera senegalensis and Piliostigma reticulatum) that co-exist with annual food crops in Sahelian agro-ecosystems. Real-time measurements were conducted for soil water content, soil water potential and microclimate variables notably; air temperature, relative humidity, wind speed, precipitation and solar irradiance. Additionally, sap flow measurements were conducted in shrub roots using the thermal dissipation technique on intact and coppiced shrubs. Monthly predawn leaf water potential was measured using a portable pressure chamber. Soil water potential (Ψ[subscript s]) at the 20 cm depth declined significantly during the dry season with diel changes in Ψ[subscript s] of −0.6 to −1.1 MPa. These variations were attributed to passive water release from shrub roots resulting in overnight rewetting of drier upper soil layers. Sap flow measurements on tap and lateral shrub roots indicated daily reversals in the direction of flow. During the peak of the dry season, both positive (toward shrub) and negative (toward soil) flows were observed in lateral shrub roots with sap flow in the lateral roots frequently negative at night and rapidly becoming positive soon after sunrise. The negative sap flow at night in superficial lateral roots and the periodic positive flow in the descending tap roots were indicative of hydraulic redistribution. Hydraulic redistribution may be an important mechanism for drought stress avoidance while maintaining plant physiological functions in both shrubs and neighboring annuals in water-limited environments.Keywords: Shrubs, Sahel, Annual food crops, Agro-ecosystems, Hydraulic redistributionKeywords: Shrubs, Sahel, Annual food crops, Agro-ecosystems, Hydraulic redistributio

A parallel randomised controlled trial of the Hypoglycaemia Awareness Restoration Programme for adults with type 1 diabetes and problematic hypoglycaemia despite optimised self-care (HARPdoc)

Impaired awareness of hypoglycaemia (IAH) is a major risk for severe hypoglycaemia in insulin treatment of type 1 diabetes (T1D). To explore the hypothesis that unhelpful health beliefs create barriers to regaining awareness, we conducted a multi-centre, randomised, parallel, two-arm trial (ClinicalTrials.gov NCT02940873) in adults with T1D and treatment-resistant IAH and severe hypoglycaemia, with blinded analysis of 12-month recall of severe hypoglycaemia at 12 and/or 24 months the primary outcome. Secondary outcomes included cognitive and emotional measures. Adults with T1D, IAH and severe hypoglycaemia despite structured education in insulin adjustment, +/− diabetes technologies, were randomised to the “Hypoglycaemia Awareness Restoration Programme despite optimised self-care” (HARPdoc, n = 49), a psychoeducation programme uniquely focussing on changing cognitive barriers to avoiding hypoglycaemia, or the evidence-based “Blood Glucose Awareness Training” (BGAT, n = 50), both delivered over six weeks. Median [IQR] severe hypoglycaemia at baseline was 5[2–12] per patient/year, 1[0–5] at 12 months and 0[0–2] at 24 months, with no superiority for HARPdoc (HARPdoc vs BGAT incident rate ratios [95% CI] 1.25[0.51, 3.09], p = 0.62 and 1.26[0.48, 3.35], p = 0.64 respectively), nor for changes in hypoglycaemia awareness scores or fear. Compared to BGAT, HARPdoc significantly reduced endorsement of unhelpful cognitions (Estimated Mean Difference for Attitudes to Awareness scores at 24 months, −2.07 [−3.37,−0.560], p = 0.01) and reduced scores for diabetes distress (−6.70[−12.50,−0.89], p = 0.02); depression (−1.86[−3.30, −0.43], p = 0.01) and anxiety (−1.89[−3.32, −0.47], p = 0.01). Despite positive impact on cognitive barriers around hypoglycaemia avoidance and on diabetes-related and general emotional distress scores, HARPdoc was not more effective than BGAT at reducing severe hypoglycaemia