Factors influencing user acceptance of a mature and embedded computer system

Productivity gains associated with investments in information technology (IT) have generally not been forthcoming. One construct that is seen as influencing the extent of individual productivity gains associated with utilising IT is user acceptance. Studies have identified a range of factors that influence acceptance in contexts where use is voluntary. However, in many modern workplaces systems are mature and embedded, affording users limited discretion over use. The current study, therefore, identified factors that influenced acceptance of a mature and embedded computer system, and identified ‘number of applications’ and ‘perceived usefulness’ as appropriate measures of acceptance for such systems

IS Project Success: Evaluating Beyond \u27On Time and To Budget\u27

There is considerable uncertainty about what to evaluate in IS projects and how this might be undertaken. Recent attention to the value that projects add to organisations indicates that evaluation at project closure needs to move beyond simplistic measures of ‘on time and to budget’. This paper argues that formal evaluation is an important aspect of IS project management and describes the evaluation activities undertaken for a project to develop a prototype web-based portal. The paper contributes to IS project management in the following ways: it sets out key dimensions for evaluating IS projects, presents an evaluation framework constructed for the characteristics of the project, and provides details of the application of the evaluation framework

Re-composing the elephant\u27 : bringing the big picture back into IS research

Information Systems is a practice-based discipline. It experiences periodic debates about the rigour and relevance of its research. The tensions between pretensions to be a &lsquo;real&rsquo; science (rigour) and the need to contribute to practice (relevance) are intensified at a time of low student enrolment, lack of a clear identity, and uncertainties about the viability of our discipline. This essay argues that decomposing phenomena into narrow topics of research to achieve rigour is damaging to our discipline if we fail to then &lsquo;recompose&rsquo; or integrate these back into understanding, lessons and guidelines for application to real-world practices. This argument is illustrated through recent work on the motors that drive changes in technology appropriation. It highlights the importance of plurality of theories and methods in understanding complex real-world phenomena in order to achieve both rigour and relevance.<br /

Investigating Training Technologies in the Australian Armed Forces

Observations of unexpected uses of technology triggered re-examination of current IS models of technology adoption, acceptance and use. The outcome is a framework for investigating the uptake of new technologies in our early twenty-first century environment. The framework draws on theories of context, portfolios and dialectics. Application of the framework to the use of training technologies in the Australian armed forces illustrates its usefulness as well as some further issues that remain relatively neglected in IS theorising. The paper concludes with implications for IS research and practice

Understanding information technology appropriation in organisations

This thesis develops understanding of the appropriation of information technology (IT) artefacts over time. Perceptions that the whole lifecycle of IT use, from pre-use, then initial use through to adaptive and stabilised use is not well understood were evaluated and supported in the initial part of the study. A generic lifecycle model of use, the model of technology appropriation (MTA), was chosen as the foundational theory for this thesis because it covers the entire IT use lifecycle, and it can be contextualised for different technologies, and user cohorts. The model was contextualised, tested and extended through data collected from three case studies that provided coverage of the entire lifecycle and involved a prototype information portal, a document management system that had been recently implemented, and an e-mail client. Defence was selected so as to provide an extreme organisational context which manifests strong structural and cultural imperatives to control use. Despite these imperatives, the findings demonstrated changes in users’ patterns of appropriations over time and heterogeneous patterns of appropriation across individuals. In addition, influences on patterns of appropriation differed throughout the lifecycle. The findings were used to contextualise the MTA by including case specific influences and patterns of appropriation. Contextualisation was followed by a critical evaluation of the fit between the core elements of the model and case findings, where the core elements represent those features of the model that exist prior to contextualisation. Whilst the MTA facilitates understanding of appropriation, the model was enhanced through: modifying core elements of the model; incorporating teleological, dialectic and evolutionary generative mechanisms; and including contextual features associated with appropriation of the IT artefacts studied. This research has produced a richer and more complete understanding of the use lifecycle in organisations than prior research. Achieving this enhanced view of the use lifecycle was supported by employing a combination of methods suited to examining the contribution of each of the generative mechanisms. This research therefore makes important theoretical and methodological contributions to the information systems field, as well as providing a basis for providing more informed guidance on how to improve the appropriation of IT artefacts in organisations

Malaria’s Missing Number: Calculating the Human Component of R0 by a Within-Host Mechanistic Model of Plasmodium falciparum Infection and Transmission

Human infection by malarial parasites of the genus Plasmodium begins with the bite of an infected Anopheles mosquito. Current estimates place malaria mortality at over 650,000 individuals each year, mostly in African children. Efforts to reduce disease burden can benefit from the development of mathematical models of disease transmission. To date, however, comprehensive modeling of the parameters defining human infectivity to mosquitoes has remained elusive. Here, we describe a mechanistic within-host model of Plasmodium falciparum infection in humans and pathogen transmission to the mosquito vector. Our model incorporates the entire parasite lifecycle, including the intra-erythrocytic asexual forms responsible for disease, the onset of symptoms, the development and maturation of intra-erythrocytic gametocytes that are transmissible to Anopheles mosquitoes, and human-to-mosquito infectivity. These model components were parameterized from malaria therapy data and other studies to simulate individual infections, and the ensemble of outputs was found to reproduce the full range of patient responses to infection. Using this model, we assessed human infectivity over the course of untreated infections and examined the effects in relation to transmission intensity, expressed by the basic reproduction number R0 (defined as the number of secondary cases produced by a single typical infection in a completely susceptible population). Our studies predict that net human-to-mosquito infectivity from a single non-immune individual is on average equal to 32 fully infectious days. This estimate of mean infectivity is equivalent to calculating the human component of malarial R0. We also predict that mean daily infectivity exceeds five percent for approximately 138 days. The mechanistic framework described herein, made available as stand-alone software, will enable investigators to conduct detailed studies into theories of malaria control, including the effects of drug treatment and drug resistance on transmission

Select pyrimidinones inhibit the propagation of the malarial parasite, Plasmodium falciparum

Plasmodium falciparum, the Apicomplexan parasite that is responsible for the most lethal forms of human malaria, is exposed to radically different environments and stress factors during its complex lifecycle. In any organism, Hsp70 chaperones are typically associated with tolerance to stress. We therefore reasoned that inhibition of P. falciparum Hsp70 chaperones would adversely affect parasite homeostasis. To test this hypothesis, we measured whether pyrimidinone-amides, a new class of Hsp70 modulators, could inhibit the replication of the pathogenic P. falciparum stages in human red blood cells. Nine compounds with IC50 values from 30 nM to 1.6 μM were identified. Each compound also altered the ATPase activity of purified P. falciparum Hsp70 in single-turnover assays, although higher concentrations of agents were required than was necessary to inhibit P. falciparum replication. Varying effects of these compounds on Hsp70s from other organisms were also observed. Together, our data indicate that pyrimidinone-amides constitute a novel class of anti-malarial agents. © 2009 Elsevier Ltd. All rights reserved

Stage-dependent localization of a novel gene product of the malaria parasite, Plasmodium falciparum

A novel Plasmodium falciparum gene, MB2, was identified by screening a sporozoite cDNA library with the serum of a human volunteer protected experimentally by the bites of P. falciparum-infected and irradiated mosquitoes. The single-exon, single-copy MB2 gene is predicted to encode a protein with an Mr of 187,000. The MB2 protein has an amino-terminal basic domain, a central acidic domain, and a carboxyl-terminal domain with similarity to the GTP-binding domain of the prokaryotic translation initiation factor 2. MB2 is expressed in sporozoites, the liver, and blood-stage parasites and gametocytes. The MB2 protein is distributed as a ~120-kDa moiety on the surface of sporozoites and is imported into the nucleus of blood-stage parasites as a ~66-kDa species. Proteolytic processing is favored as the mechanism regulating the distinct subcellular localization of the MB2 protein. This differential localization provides multiple opportunities to exploit the MB2 gene product as a vaccine or therapeutic target

Modeling Within-Host Effects of Drugs on Plasmodium falciparum Transmission and Prospects for Malaria Elimination

Achieving a theoretical foundation for malaria elimination will require a detailed understanding of the quantitative relationships between patient treatment-seeking behavior, treatment coverage, and the effects of curative therapies that also block Plasmodium parasite transmission to mosquito vectors. Here, we report a mechanistic, within-host mathematical model that uses pharmacokinetic (PK) and pharmacodynamic (PD) data to simulate the effects of artemisinin-based combination therapies (ACTs) on Plasmodium falciparum transmission. To contextualize this model, we created a set of global maps of the fold reductions that would be necessary to reduce the malaria RC (i.e. its basic reproductive number under control) to below 1 and thus interrupt transmission. This modeling was applied to low-transmission settings, defined as having a R0<10 based on 2010 data. Our modeling predicts that treating 93–98% of symptomatic infections with an ACT within five days of fever onset would interrupt malaria transmission for ∼91% of the at-risk population of Southeast Asia and ∼74% of the global at-risk population, and lead these populations towards malaria elimination. This level of treatment coverage corresponds to an estimated 81–85% of all infected individuals in these settings. At this coverage level with ACTs, the addition of the gametocytocidal agent primaquine affords no major gains in transmission reduction. Indeed, we estimate that it would require switching ∼180 people from ACTs to ACTs plus primaquine to achieve the same transmission reduction as switching a single individual from untreated to treated with ACTs. Our model thus predicts that the addition of gametocytocidal drugs to treatment regimens provides very small population-wide benefits and that the focus of control efforts in Southeast Asia should be on increasing prompt ACT coverage. Prospects for elimination in much of Sub-Saharan Africa appear far less favorable currently, due to high rates of infection and less frequent and less rapid treatment