Search PubMed⌕ Search

Biomedical subjects

J Aarts

Publications and source records attributed to J Aarts.

At least 19 recordsLinked to original sources
PubMed2006

Critical voltage of a mesoscopic superconductor.

We study the influence of a voltage-driven nonequilibrium of quasiparticles on the properties of short mesoscopic superconducting wires. We employ a numerical calculation based upon the Usadel equation. Going beyond linear response, we find a nonthermal energy distribution of the quasiparticles caused by the applied bias voltage. It is demonstrated that this nonequilibrium drives the system from the superconducting state to the normal state, at a current density far below the critical depairing current density.

Journal Article↗
PubMed2006

Same systems, different outcomes--comparing the implementation of computerized physician order entry in two Dutch hospitals.

OBJECTIVES: To compare the outcome of the implementation of computerized physician order entry (CPOE) systems in two Dutch hospitals. METHODS: Qualitative research methods, including interviews in both hospitals, observations of system in use, observations of staff meetings and document analysis were used to understand the implementation of CPOE. The transcribed texts and implementation documents were analyzed for relevant concepts. The transcripts and field notes were analyzed using a heuristic success and failure model with medical work as the primary focus. RESULTS: Occasions that determined the outcome of the implementation were classified according to factors that may influence the success or failure of implementing systems. CONCLUSIONS: The themes and patterns that emerged from the data helped validate the concept of medical work as the primary focus of our analysis model; in addition the concept of a support base necessary to accept changes in medical work that result from introducing CPOE may help to understand the different implementation outcomes.

Diffusion of Innovation↗
PubMed2004

Enhancement of the superconducting transition temperature in Nb/permalloy bilayers by controlling the domain state of the ferromagnet.

In (S/F) hybrids the suppression of superconductivity by the exchange field h(ex) of the ferromagnet can be partially lifted when different directions of h(ex) are sampled simultaneously by the Cooper pair. In F/S/F trilayers where the magnetization directions of the F layers can be controlled separately, this leads to the so-called spin switch. Here we show that domain walls in a single F layer yield a similar effect. We study the transport properties of Ni(0.80)Fe(0.20)/Nb bilayers structured in strips of different sizes. For large samples a clear enhancement of superconductivity takes place in the resistive transition, in the very narrow field range (order of 0.5 mT) where the magnetization of the Py layer switches and many domains are present. This effect is absent in microstructured samples.

Journal Article↗
PubMed2003

ICT in health care: sociotechnical approaches.

The importance of the social sciences for medical informatics is increasingly recognized. As ICT requires inter-action with people and thereby inevitably affects them, understanding ICT requires a focus on the interrelation between technology and its social environment. Sociotechnical approaches increase our understanding of how ICT applications are developed, introduced and become a part of social practices. Socio-technical approaches share several starting points: 1) they see health care work as a social, 'real life' phenomenon, which may seem 'messy' at first, but which is guided by a practical rationality that can only be overlooked at a high price (i.e. failed systems). 2) They see technological innovation as a social process, in which organizations are deeply affected. 3) Through in-depth, formative evaluation, they can help improve system design and implementation.

Computer Communication Networks↗
PubMed2002

STM imaging of flux line arrangements in the peak effect regime.

We present the results of a study of vortex arrangements in the peak-effect regime of 2H-NbSe2 by scanning tunneling microscopy. By slowly increasing the temperature in a constant magnetic field, we observed a sharp transition from collective vortex motion to positional fluctuations of individual vortices at the temperature which coincides with the onset of the peak effect in ac susceptibility. We conclude that the peak effect is a disorder driven transition, with the pinning energy winning against the elastic energy.

Journal Article↗
PubMed2001

Coupling of two superconductors through a ferromagnet: evidence for a pi junction.

We report measurements of the temperature dependence of the critical current, I(c), in Josephson junctions consisting of conventional superconducting banks of Nb and a weakly ferromagnetic interlayer of a CuxNi1-x alloy, with x around 0.5. With decreasing temperature I(c) generally increases, but for specific thicknesses of the ferromagnetic interlayer, a maximum is found followed by a strong decrease down to zero, after which I(c) rises again. Such a sharp cusp can be explained only by assuming that the junction changes from a 0-phase state at high temperatures to a pi phase state at low temperatures.

Journal Article↗
PubMed2000

A coherent approach to health informatics education: results of the Dutch curriculum project.

From the beginning a coherent approach to health informatics education has been aimed for in our project to develop learning materials. The features are the thematic approach of the contents, the interrelationship of the modules and the didactical approach embedded in the learning materials. Following results have been achieved. Learning materials have been developed for the following themes: healthcare policy and management, delivery of professional care (specific for nursing and allied health), more generic themes such as electronic patient record, clinical decision making, classification and coding of healthcare data and knowledge based systems. Software made available by private companies has been selected for use in the learning modules. In specific cases the available software products did not match the criteria to support the learning materials. In these cases model applications have been developed that can be considered as forerunners for systems in practical use. Already some companies have expressed interest to adapt our home grown products for use in clinical practice. The modules are based on a model curriculum that has been developed by Aarts et al in 1995. New developments in healthcare have prompted modification of the contents of a few modules. For example, a module has been redefined to cover the important issue of logistics in healthcare. The module on patient education has been adapted to take into account the resources available on the Internet. Also, new insights in the effectiveness of computer-based patient education have been taken into account. The module on informatics for disabled persons has been focussed on computer-based aids and is being linked to the EU-project "Impact" aimed at increasing knowledge about assistive technology. However, the model curriculum has proved to be reasonable robust as a base for our project to develop learning materials for health informatics.

Curriculum↗
PubMed1999

Spatially Inhomogeneous Metal-Insulator Transition in Doped Manganites.

Scanning tunneling spectroscopy was used to investigate single crystals and thin films of La(1-x)Ca(x)MnO(3) (with x of about 0.3), which exhibit colossal magnetoresistance. The different spectroscopic signatures of the insulating (paramagnetic) and metallic (ferromagnetic) phases enable their spatial extent to be imaged down to a lateral scale of the order of 10 nanometers. Above the bulk transition temperature T(c), the images show mostly insulating behavior. Below T(c), a phase separation is observed where inhomogeneous structures of metallic and more insulating areas coexist and are strongly field dependent in their size and structure. Insulating areas are found to persist far below T(c). These results suggest that the transition and the associated magnetoresistance behavior should be viewed as a percolation of metallic ferromagnetic domains.

Journal Article↗
PubMed1999

Using a descriptive model of change when implementing large scale clinical information systems to identify priorities for further research.

In this paper we identify domains for research based on a model that describes the stages of change when designing and implementing large scale information and communication technology throughout a healthcare organization. We use the model in the case of the electronic patient record systems. We suggest that the research agenda should include approaches from the social and business sciences.

Humans↗
PubMed1998

Exploring factors required for successful implementation of healthcare informatics.

This paper examines factors that are essential for a successful implementation of healthcare informatics in professional curricula. These factors are related to the design framework of the learning materials that have been developed as a part of a Dutch model curriculum of healthcare informatics. Next some ideas and suggestions for a successful implementation are presented.

Curriculum↗
PubMed1995

A model curriculum of health care informatics for Dutch higher professional education.

This paper describes the results of a two year project to design a model curriculum of health care informatics for Dutch higher professional education. The core of the curriculum are sixteen modules which cover the broad range of medical informatics and which are closely related to the profiles of the professions involved (nursing, physiotherapy, speech therapy, occupational therapy and dietetics). The curriculum emphasizes the need of using structured data and information to perform tasks in health care delivery and management, for which modern information technology is indispensable. The model curriculum will enable faculty to redesign existing undergraduate programs and to select the contents they see appropriate. In this way we hope that the model curriculum will contribute to an innovative attitude of future graduating health care professionals. A new three year project just has started to develop learning materials using professional health care software based on the sixteen modules of the curriculum.

Curriculum↗