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PubMed2005

WebCT in occupational therapy clinical education: implementing and evaluating a tool for peer learning and interaction.

As occupational therapy expands into new practice arenas such as wellness, driver rehabilitation and ergonomics, educators are challenged to revise the curriculum as well as change educational technology. One of the changes in occupational therapy educational programmes is the utilization of on-line teaching. The purpose of this study was to evaluate the learning experiences of 42 occupational therapy students who were involved in a virtual learning environment during their six-week fieldwork placement. The results indicated that the majority of students enjoyed participating in this web-based learning environment (WebCT). A vast array of themes emerged from the on-line discussion and these themes reflected different levels of learning. Participation in WebCT during fieldwork appears to have a beneficial effect on student learning and achievement of stage 1 learning objectives by supporting students in peer learning. Other benefits include improving student autonomy during fieldwork, supporting self-directed learning and stimulating higher order thinking. Although the results of this study were positive there is still a need to further evaluate the effectiveness of web-based learning as an alternative to traditional educational methods during fieldwork education.

Computer-Assisted Instruction↗

PubMedDate not supplied

Using situs for flexible and rigid-body fitting of multiresolution single-molecule data.

We describe here a set of multiresolution visualization and docking procedures that we refer to as the Situs package. The package was developed to provide an efficient and robust method for the fitting of atomic structures into low-resolution data. The current release was optimized specifically for the visualization and docking of single molecules. A novel 3D graphics viewer, volslice3d, was developed for the package to provide an immersive virtual reality environment for measuring and rendering volumetric data sets. The precision of single-molecule, rigid-body docking was tested on simulated (noise-free) low-resolution density maps. For spatial resolutions near 20 A typically arising in electron microscopy image reconstructions, a docking precision on the order of 1 A can be achieved. The shape-matching score captured the correct solutions in all 10 trial cases and was sufficiently stringent to yield unique matches in 8 systems. Novel routines were developed for the flexible docking of atomic structures whose shape deviates from the corresponding low-resolution shape. Test calculations on isoforms of actin and lactoferrin demonstrate that the flexible docking faithfully reproduces conformational differences with a precision < 2 A if atomic structures are locally conserved.

Actins↗

PubMed2002

Neurodevelopmental aspects of spatial navigation: a virtual reality fMRI study.

Navigation in spatial contexts has been studied in diverse species, yielding insights into underlying neural mechanisms and their phylogenetic progression. Spatial navigation in humans is marked by age-related changes that may carry important implications for understanding cortical development. The emergence of "allocentric" processing, reflecting that ability to use viewer-independent spatial abstractions, represents an important developmental change. We used fMRI to map brain regions engaged during memory-guided navigation in a virtual reality environment in adolescents and adults. Blood oxygen level-dependent (BOLD) signal was monitored in eight adolescents and eight adults in a 1.5-T MRI scanner during three conditions: (1) memory-guided navigation (NAV); (2) arrow-guided navigation (ARROW); and (3) fixation (FIX). We quantified navigation ability during scanning and allocentric memory after scanning, based on subjects' ability to label a previously unseen, aerial view of the town. Adolescents and adults exhibited similar memory-guided navigation ability, but adults exhibited superior allocentric memory ability. Memory-guided navigation ability during scanning correlated with BOLD change between NAV/ARROWS in various regions, including a right frontal and right-anterior medial temporal lobe region. Age group and allocentric memory together explained significant variance in BOLD change in temporoparietal association cortex and the cerebellum, particularly in the left hemisphere. Consistent with developmental models, these findings relate maturation in the coding of spatial information to functional changes in a distributed, left-lateralized neural network.

Adolescent↗

PubMed2000

Security model for picture archiving and communication systems.

The modern information revolution has facilitated a metamorphosis of health care delivery wrought with the challenges of securing patient sensitive data. To accommodate this reality, Congress passed the Health Insurance Portability and Accountability Act (HIPAA). While final guidance has not fully been resolved at this time, it is up to the health care community to develop and implement comprehensive security strategies founded on procedural, hardware and software solutions in preparation for future controls. The Virtual Radiology Environment (VRE) Project, a landmark US Army picture archiving and communications system (PACS) implemented across 10 geographically dispersed medical facilities, has addressed that challenge by planning for the secure transmission of medical images and reports over their local (LAN) and wide area network (WAN) infrastructure. Their model, which is transferable to general PACS implementations, encompasses a strategy of application risk and dataflow identification, data auditing, security policy definition, and procedural controls. When combined with hardware and software solutions that are both non-performance limiting and scalable, the comprehensive approach will not only sufficiently address the current security requirements, but also accommodate the natural evolution of the enterprise security model.

Computer Communication Networks↗

PubMed2000

Planning factors for developing an enterprise-wide picture archiving and communication system maintenance program.

Picture archiving and communication system (PACS) maintenance on an individual site basis has historically been a complex and costly challenge. With the advent of enterprise-wide PACS projects such as the Virtual Radiology Environment (VRE) project, the challenge of a maintenance program with even more complexities has presented itself. The approach of the project management team for the VRE project is not one of reactive maintenance, but one of highly proactive planning and negotiations, in hopes of capitalizing on the economies of scale of an enterprise-wide PACS maintenance program. A proactive maintenance program is one aspect of life-cycle management. As with any capital acquisition, life-cycle management may be used to manage the specific project aspects related to PACS. The purpose of an enterprise-wide warranty and maintenance life-cycle management approach is to maintain PACS at its maximum operational efficiency and utilization levels through a flexible, shared, yet symbiotic relationship between local, regional, and vendor resources. These goals include providing maximum operational performance levels on a local, regional, and enterprise basis, while maintaining acceptable costs and resource utilization levels. This goal must be achieved without negatively impacting point of care activities, regardless of changes to the clinical business environment.

Cost-Benefit Analysis↗

PubMed1999

Meta-manager: a requirements analysis.

The digital imaging network-picture-archiving and communications system (DIN-PACS) will be implemented in ten sites within the Great Plains Regional Medical Command (GPRMC). This network of PACS and teleradiology technology over a shared T1 network has opened the door for round the clock radiology coverage of all sites. However, the concept of a virtual radiology environment poses new issues for military medicine. A new workflow management system must be developed. This workflow management system will allow us to efficiently resolve these issues including quality of care, availability, severe capitation, and quality of the workforce. The design process of this management system must employ existing technology, operate over various telecommunication networks and protocols, be independent of platform operating systems, be flexible and scaleable, and involve the end user at the outset in the design process for which it is developed. Using the unified modeling language (UML), the specifications for this new business management system were created in concert between the University of Arizona and the GPRMC. These specifications detail a management system operating through a common object request brokered architecture (CORBA) environment. In this presentation, we characterize the Meta-Manager management system including aspects of intelligence, interfacility routing, fail-safe operations, and expected improvements in patient care and efficiency.

Arizona↗

PubMed2001

Procedural motor learning in Parkinson's disease.

We have been investigating motor control and learning in parkinsonian subjects. In the current study, we sought to explore the existence of deficits in procedural motor learning, which is a form of implicit motor learning where skill improves over repetitive blocks of trials. We sought to determine, in particular, whether any such deficit is accentuated during specific types or phases of learning. We would expect that those specific learning tasks would require the greatest participation of the basal ganglia. Numerous studies have found that Parkinson's disease (PD) patients may show deficits in learning. Combined with information about basal ganglia neuronal connections and activity, this led some investigators to suggest that one of the key functions of the basal ganglia is to facilitate learning. To investigate these learning deficits, we used a robotic device to generate conservative force fields that disturbed the subjects' arm movements, thereby generating a "virtual mechanical environment" that subjects learned to manipulate. Movements were successively grouped into blocks comprising five different conditions: motor performance, early learning, late learning, negative transfer, and aftereffect motor performance. Our results with eight right-handed PD subjects and nine age-matched controls showed a relative decrease in the rate of learning for the PD patients in all blocks, but greater differences emerged between groups during novelty phases of learning. In particular, the difference in performance during the negative transfer condition reached statistical significance, suggesting that the basal ganglia might be a key center for "switching" motor patterns. Our results support the hypothesis that deficiencies in procedural motor learning are characteristic of PD. They add to existing evidence which has suggested a key role for the basal ganglia when new sensorimotor mappings are required by novel task environments. Better understanding of these deficits should facilitate the rehabilitation of PD patients.

Aged↗

PubMed2006

Virtual parameter-estimation experiments in Bioprocess-Engineering education.

Cell growth kinetics and reactor concepts constitute essential knowledge for Bioprocess-Engineering students. Traditional learning of these concepts is supported by lectures, tutorials, and practicals: ICT offers opportunities for improvement. A virtual-experiment environment was developed that supports both model-related and experimenting-related learning objectives. Students have to design experiments to estimate model parameters: they choose initial conditions and 'measure' output variables. The results contain experimental error, which is an important constraint for experimental design. Students learn from these results and use the new knowledge to re-design their experiment. Within a couple of hours, students design and run many experiments that would take weeks in reality. Usage was evaluated in two courses with questionnaires and in the final exam. The faculties involved in the two courses are convinced that the experiment environment supports essential learning objectives well.

Biomedical Engineering↗

PubMed1985

Mercury in the open Mediterranean: evidence of contamination?

In relation to the previously observed higher Hg concentrations in the tissues of certain Mediterranean fish (e.g. mackerel and tuna) compared with the same species in the Atlantic, the evidence for anomolously high Hg contamination of the Mediterranean has been examined. Four aspects have been addressed: the reliability of analytical measurements; the paucity of data on Hg in the Mediterranean and other oceanic areas; the actual levels of Hg in truly open-ocean waters; and ecological factors which may play a role in the enrichment of Hg in Mediterranean fish. Recent evidence suggests that former measurements of Hg in sea water are inadequate, and overestimate the concentrations of Hg in oceanic waters. Even today, intercalibration studies suggest that there are serious problems in the determination of Hg at the levels present in open oceans. A comparison of the most recent reliable data indicates that Mediterranean open-ocean waters are not enriched in Hg relative to the North Atlantic or other open-ocean areas. Similarly, no evidence exists for Hg anomalies in deep-ocean sediments in the Mediterranean, although it is apparent that localised coastal anomalies do occur as a result of natural and anthropogenic Hg sources. Generally, there is a severe lack of data on total Hg concentrations in truly open-ocean environments, and virtually no data on alkyl forms of Hg. Geographic comparisons of Hg in plankton and small pelagic fish do not indicate the presence of higher Hg concentrations in the Mediterranean Sea compared with oceanic regimes. Since these lower trophic species serve as a source of food for larger predaceous fish, e.g. tuna, the origin of the high Hg content in top-level predators is difficult to explain by evoking solely food chain relationships. In trying to resolve the question of why high Hg concentrations are found in certain Mediterranean fish, future studies should include an examination of the alkyl as well as inorganic forms of Hg, and ecological factors such as growth rates and feeding regime.

Animals↗

PubMed1991

Local depletion of monoamines induced with in vivo voltammetry in the cat brain.

A significant depletion of the electroactive monoamines and their metabolites in the vicinity of a carbon fiber microelectrode may be induced by in vivo staircase voltammetry in the brain, even if the duration of the voltammetric scans is relatively short (approximately 5 s). The variation of this depletion was determined in the extracellular fluid of the cat thalamus at different durations of the pauses separating consecutive measurements. Pauses not shorter than 5 min ensured a nearly full relaxation, so that at the beginning of each subsequent scan a virtually undisturbed environment surrounded the electrode. With pauses shorter than 5 min, it is still possible to monitor major changes in the monoamine concentration. Staircase scans separated with 45 s pauses, for example, were suitable to study the increase in monoamine levels after administration of reserpine, and release phenomena stimulated with KCl were monitored with frequently repeated voltammetric pulses. The electrochemically induced depletion, on the other hand, can be used for characterizing the dynamics of mass transport in the studied brain structure. This was demonstrated with staircase voltammetry alternated with pauses of 1-100 s, and with quasi-chronoamperometry. In vivo brain voltammetry is generally used for monitoring extracellular monoamine (including dopamine) levels. These may be significantly altered by the voltammetric measurement itself through depletion in the vicinity of the electrode. This effect can be minimized with appropriate selection of sampling intervals and other parameters of staircase voltammetry. Conversely, depletion and the following relaxation can be used for determining dynamic characteristics of the studied brain structure which would be difficult to obtain otherwise.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2006

Effects of D-cycloserine on extinction: translation from preclinical to clinical work.

Administration of benzodiazepines or serotonin reuptake inhibitors in combination with behavior therapy for the treatment of many anxiety disorders has generally lead to only modest gains. In this article we suggest that pharmacotherapy aimed not at treating the symptoms of anxiety but instead aimed at improving the learning that takes place in exposure therapy might actually improve the effectiveness of exposure therapy. This idea was based on animal work showing that the partial N-methyl-D-aspartate (NMDA) agonist D-cycloserine (DCS) facilitated extinction of fear when given either before or shortly after exposure to fearful cues, reduced return of fear that is normally seen when extinction training is followed by stress, and led to generalized extinction, where DCS given in combination with exposure to one fearful cue led to extinction to another cue previously paired with the same aversive event. These finding suggested that DCS might facilitate exposure-based psychotherapy, which was verified in a small clinical study showing that DCS facilitated exposure therapy for fear of heights in a well-controlled virtual reality environment.

Animals↗

PubMed2006

Humans ignore motion and stereo cues in favor of a fictional stable world.

As we move through the world, our eyes acquire a sequence of images. The information from this sequence is sufficient to determine the structure of a three-dimensional scene, up to a scale factor determined by the distance that the eyes have moved. Previous evidence shows that the human visual system accounts for the distance the observer has walked and the separation of the eyes when judging the scale, shape, and distance of objects. However, in an immersive virtual-reality environment, observers failed to notice when a scene expanded or contracted, despite having consistent information about scale from both distance walked and binocular vision. This failure led to large errors in judging the size of objects. The pattern of errors cannot be explained by assuming a visual reconstruction of the scene with an incorrect estimate of interocular separation or distance walked. Instead, it is consistent with a Bayesian model of cue integration in which the efficacy of motion and disparity cues is greater at near viewing distances. Our results imply that observers are more willing to adjust their estimate of interocular separation or distance walked than to accept that the scene has changed in size.

Computer Simulation↗

PubMed2006

Toward direct biocontrol using surface EMG signals: control of finger and wrist joint models.

Increased interest in virtual reality (VR) and telemanipulation has created a growing need for the development of new interfacing devices for measuring controlling actions of the human hand. The objective of the present study was to determine if surface electromyography signals (SEMG) from the flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU) generated during flexion-extension of the human index finger and wrist can be used for controlling the flexion-extension of the finger and wrist of a simple geometric computer model. A simple geometric computer model of finger and wrist joints was developed. Eighteen subjects controlled the computer model using the SEMG signals from their FDS and FCU. The results indicate that the SEMG signals from the FDS and FCU muscles can be used as a direct biocontrol technique for controlling the finger and wrist models. This study establishes the proof of concept for direct biological control of the dynamic motion of the finger and wrist models for use in virtual reality environments and telemanipulation.

Computer Simulation↗

PubMed2006

An exploration of on-line access by non-traditional students in higher education: a case study.

The nature of Higher Education (HE) has seen many changes throughout the last decade. The agenda for widening participation in HE has led to an increase in the number of students with a broader range of educational backgrounds. At the same time there has been a surge in the development of digitalisation and the convergence of computing and telecommunications technologies available for use in education. This paper discusses the outcomes of a case study, conducted in a School of Health Studies within a northern English University, which identified the extent to which 'non-traditional' students access on-line learning facilities, such as virtual learning environments and library networks, and what factors enhanced or formed barriers to access. 'Non-traditional' students, for the purpose of this study, were defined as mature students who were returning to higher education after a considerable break. The outcomes indicated that skill deficit is a major obstacle for many 'non-traditional' students. The paper explores this issue in depth and suggests potential ways forward for the delivery of technology supported learning for 'non-traditional' students in Higher Education.

Adult↗

PubMed2003

A task scheduler framework for self-powered wireless sensors.

The cost and inconvenience of cabling is a factor limiting widespread use of intelligent sensors. Recent developments in short-range, low-power radio seem to provide an opening to this problem, making development of wireless sensors feasible. However, for these sensors the energy availability is a main concern. The common solution is either to use a battery or to harvest ambient energy. The benefit of harvested ambient energy is that the energy feeder can be considered as lasting a lifetime, thus it saves the user from concerns related to energy management. The problem is, however, the unpredictability and unsteady behavior of ambient energy sources. This becomes a main concern for sensors that run multiple tasks at different priorities. This paper proposes a new scheduler framework that enables the reliable assignment of task priorities and scheduling in sensors powered by ambient energy. The framework being based on environment parameters, virtual queues, and a state machine with transition conditions, dynamically manages task execution according to priorities. The framework is assessed in a test system powered by a solar panel. The results show the functionality of the framework and how task execution reliably is handled without violating the priority scheme that has been assigned to it.

Algorithms↗

PubMed2002

Visual perception of planar orientation: dominance of static depth cues over motion cues.

We measured the ability to report the tilt (direction of maximal slope) of a plane under monocular viewing conditions, from static depth cues (square grid patterns) and motion parallax (small rotations of the plane about a frontoparallel axis). These two cues were presented separately, or simultaneously. In the latter case they specified tilts that were either collinear (coherent case) or orthogonal (conflict case). The field of view was small (8 degrees) or large (60 degrees). In small field, for motion parallax, the reported tilt depends strongly on the orientation of the plane relative to the rotation axis, being totally ambiguous when tilt is collinear with the rotation axis. In contrast, in large field, the reported tilt depends little on this variable, and is accurately specified by motion cues. In both cases static cues strongly dominated the tilt reports. Hence static grid patterns constitute robust tilt cues, which can dominate contradictory tilt indications from motion parallax, and should be considered as essential for the visual orientation during locomotion, or the immersion in virtual reality environments.

Adult↗

PubMed2003

Experience-dependent visual cue recalibration based on discrepancies between visual and haptic percepts.

We studied the hypothesis that observers can recalibrate their visual percepts when visual and haptic (touch) cues are discordant and the haptic information is judged to be reliable. Using a novel visuo-haptic virtual reality environment, we conducted a set of experiments in which subjects interacted with scenes consisting of two fronto-parallel surfaces. Subjects judged the distance between the two surfaces based on two perceptual cues: a visual stereo cue obtained when viewing the scene binocularly and a haptic cue obtained when subjects grasped the two surfaces between their thumb and index fingers. Visual and haptic cues regarding the scene were manipulated independently so that they could either be consistent or inconsistent. Experiment 1 explored the effect of visuo-haptic inconsistencies on depth-from-stereo estimates. Our findings suggest that when stereo and haptic cues are inconsistent, subjects recalibrate their interpretations of the visual stereo cue so that depth-from-stereo percepts are in greater agreement with depth-from-haptic percepts. In Experiment 2 the visuo-haptic discrepancy took a different form when the two surfaces were near the subject than when they were far from the subject. The results indicate that subjects recalibrated their interpretations of the stereo cue in a context-sensitive manner that depended on viewing distance, thereby making them more consistent with depth-from-haptic estimates at all viewing distances. Together these findings suggest that observers' visual and haptic percepts are tightly coupled in the sense that haptic percepts provide a standard to which visual percepts can be recalibrated when the visual percepts are deemed to be erroneous.

Adolescent↗

PubMed2001

A new approach for the real-time simulation of tissue deformations in surgery simulation.

Simulation of the behaviour of elastic objects in real time is one of the present objectives of computer graphics. One of its fields of application lies in virtual reality, mainly in surgery simulation systems. Models used for the construction of objects with deformable behaviour in computer graphics are known as deformable models. These have two conflicting characteristics: interactivity and movement realism. The deformable models developed up till now have promoted one characteristic to the detriment of the other. In this paper, a new approach is proposed based on boundary element methods (BEM). This is characterised by a positive equilibrium between speed and realism and great robustness. These properties along with the experimental results described in this paper permit one to assert that establishing deformable models with BEM is a reliable method to model objects in virtual reality environments for surgery simulation. In addition to that, the required elasticity parameters could be obtained experimentally through the use of a pig's liver.

Algorithms↗