A nonlinear approach to testing the unit root null hypothesis : an application to international health expenditures

In this article, we examine the unit root null hypothesis for per capita total Health Expenditures (HEs), per capita private HEs and per capita public HEs for 29 Organization for Economic Co-operation and Development (OECD) countries. The novelty of our work is that we use a new nonlinear unit root test that allows for one structural break in the data series. We find that for around 45% of the countries, we are able to reject the unit root hypothesis for each of the three HE series. Moreover, using Monte Carlo simulations, we show that our proposed unit root model has better size and power properties than the widely used Augmented Dickey–Fuller (ADF) and Lagrange Multiplier (LM) type tests.

Vascular access surveillance : the role of the access nurse in the renal dialysis unit.

Introduction
In January 2006, the Renal Dialysis Unit at Geelong Hospital appointed a Vascular Access Nurse. A Transonic Flow Qc HDO2 Ultrasound Dilution Monitor was purchased to monitor access flow and recirculation in arteriovenous fistulae in an attempt to predict AVF stenoses requiring early surgical correction.

Methods
A bi-monthly monitoring program tested all facility-based patients. 82 patients were assessed for access flow and recirculation between February and December 2006.

Results
18 (22%) had poor AVF function; 13 with access flows <500ml/minute on initial testing and 5 with an access flow decreasing >25% over a four month period. Of the 18 patients shown to have poor access flow, 2 died within one month of measurement while 5 were too frail to attempt corrective surgery. The remaining 11 proceeded to ultrasound or fistulography. A >50% stenosis was detected in all 11 cases. Of these, 4 had successful vein patch surgery and one had PTFE grafting, each with marked improvement in access flow. One had failed vein patch surgery requiring creation of a femoral AVF, one patient required cvc insertion to await AVF creation, and one had failed stenting requiring a permanent cvc. 3 died before planned surgery.

Conclusion
5 of the 82 patients that had access flow assessment, and needed further evaluation, proceeded to successful pre-emptive surgical intervention. We believe the Transonic is a useful adjunct to routine clinical AVF surveillance, in providing early evidence of AVF failure that can be avoided by pre-emptive surgery.

Creating value in an introductory business IS and IT unit

Given the downturn in student enrolments in Information Systems (IS) and Information Technology (IT) units, and the poor performance of a first-year IS and IT common-core unit in a business school, a new unit was developed. Action and design science research methods were employed. The new unit has a unique focus on two key skills and on modern IT and information literacy. The first skill involves describing information systems, and the second, determining how to create business value with IT in specific business contexts. Modern IT tools like a Web-based productivity suite and professional networking services are introduced, together with advanced search techniques and services and an information quality evaluation framework. The evaluation of the utility and efficacy of the unit is based on the institutional standard student feedback survey and unsolicited feedback. The unit has achieved a significant improvement in evaluation results and feedback from students, as well as converting students who were previously averse to IS and IT to study further in these areas.

Predicting the acceptance of unit guide information systems

Information Systems can play an important role in ensuring and improving the quality of education provided. However, lack of acceptance of these information systems and resistance of technology innovations by the end users limit the expected benefits of the system. This research attempts to identify the key determinants for the acceptance of the Unit Guide Information Systems (UGIS) in the Australian higher education sector. The technology acceptance model (TAM), social cognitive theory (SCT) and model of PC utilization (MPCU) are combined to provide a new framework for this analysis. Results of the study are consistent with the technology acceptance factors for explaining the behavioural intention of the academics. The study also shows the effects of application specific self-efficacy, application specific anxiety and social influence on the acceptance of UGIS. Implications of the results are discussed within the context of unit guides and curriculum mapping.

Estimating non-response bias in a web-based survey of technology acceptance : a case study of unit guide information systems

Surveys are mostly challenged by response rates. Among the various types of survey research, web-based (internet-based/electronic/online) surveys are commonly used for data collection for a geographically diverse population. In surveys with high/low response rates, non-response bias can be a major concern. While it is not always possible to measure the actual bias due to non-response there are different approaches and techniques that help to identify reasons of non-response bias. The aims of this paper are twofold. (1) To provide an appropriate, interesting and important non-response bias case study for future web-based surveys that will provide guidance to other Information Systems researchers. The case-study concerns an online-survey to evaluate a technology acceptance model for Unit Guide Information systems (UGIS). (2) To discuss how nonresponse bias in a web-based technology acceptance study of an information system (UGIS in this case) can be contained and managed.

A cascade genetic algorithm and particle swarm approach for solving unit commitment and economic dispatch problems

Positive Unit commitment and economic dispatch are two important decisions in thermal power generation scheduling. The tasks involve determination and allocation of power generation to thermal units that minimize the total power generation cost and satisfy the production constraints.This paper presents a cascade Genetic Algorithm and Particle Swarm Optimization (GA-PSO) approach for solving thermal power generation scheduling based on a layered matrix encoding structure.The proposed hybrid method is compared to layered matrix encoding GA using the thermal power generation problem given in Williams [1] to demonstrate its effectiveness in generating an optimal, cost-effective power generation schedule.The results showed that cascade GA-PSO outperformed the layered matrix encoding GA in minimizing the total power production cost for unit commitment and power dispatch problems.

Comparing the small sample properties of two break Lagrange Multiplier unit root tests

In this note, we examine the size and power properties and the break date estimation accuracy of the Lee and Strazicich (LS, 2003) two break endogenous unit root test, based on two different break date selection methods: minimising the test statistic and minimising the sum of squared residuals (SSR). Our results show that the performance of both Models A and C of the LS test are superior when one uses the minimising SSR procedure.

Early diagnosis and treatment of necrotizing fasciitis can improve survival : an observational intensive care unit cohort study

Background
The aim of this study was to describe the clinical characteristics, causative pathogens, clinical management and outcomes of patients presenting to a tertiary adult Australian intensive care unit (ICU) with a diagnosis of necrotizing fasciitis (NF).
Methods
This retrospective observational study was conducted in a 19-bed, level III, adult ICU in a 450-bed tertiary, regional hospital. Clinical databases were accessed for patients diagnosed with NF and admitted to The Geelong Hospital ICU between 1 February 2000 and 1 June 2011. Information on severity of sepsis, surgical procedures and microbiological results were collected.
Results
Twenty patients with NF were identified. The median age was 52.5 years and 38% were female. The overall mortality rate was 8.3%. Common co-morbidities were diabetes (21%) and heart failure (17%), although 50% of patients had no co-morbidities. Group A Streptococcus was the identified pathogen in 11 (46%) patients, and Streptococcus milleri group in 5 (21%) patients. Hyperbaric oxygen therapy was not used in the majority of patients. The initial antibiotics administered were active against subsequently cultured bacteria in 83% of patients. Median time to surgical debridement was 20 h. Diagnosis and management was delayed in the nosocomial group.
Conclusions
This study reports physiological data, aetiology and therapeutic interventions in NF for an adult tertiary hospital. We demonstrate one of the lowest reported mortality rates, with early surgical debridement being achieved in the majority of patients. The main delay was found to be in the diagnosis of NF.

Using quantitative and qualitative unit profiling for identifying the contribution of library resources to teaching quality

This paper presents the development and application of a new methodology incorporating both quantitative and qualitative profiling to help discern the characteristics of units of study that are the differentiators of student ratings of library resource quality. From the sub-set of those units with an ‘unremarkable’ rating for teaching quality, those units with the ‘extreme’ library resource quality ratings were selected for investigation. Examination of the handbook descriptions for those units suggests that units of study which explicitly incorporate student interaction with the wider literature and other information resources beyond those provided within the unit environment may lead students to engage with the library in deeper ways that highlight the value of library resources, and hence lead to higher mean ratings of library resource quality. This finding suggests potential areas for intervention to enhance student perceptions of the quality of library resources.

Women directors on boards of Australian Real Estate Investment Trusts

Purpose – This is the first paper which aims to investigate factors that might influence the gender composition of boards of directors of Australian Real Estate Investment Trusts (A-REITs).

Design/methodology/approach – This study follows Mateos de Cabo, Gimeno and Nieto and the gender diversity literature and investigates the existence and number of women directors on the boards of directors of 37 A-REITs from 2006 to 2011.

Findings – There is evidence that larger (by market capitalization) A-REITs are more likely to employ a woman director and that A-REITs with larger boards are more likely to employ a woman director and indeed more women directors. It also appears that A-REITs whose head office is in Sydney are more likely to employ a woman director and also more women directors.

Practical implications – Women seeking to be engaged as directors of A-REITs are more likely to be employed by larger A-REITs (by market capitalization), those with larger boards and those located in Sydney.

Originality/value – This paper adds to the existing literature on gender diversity by examining the factors that appear to influence the employment of women on A-REIT Boards.

Factors to drive clinical practice improvement in a Malaysian intensive care unit : assessment of organisational readiness using a mixed method approach

This study assessed organisational readiness and factors to drive clinical practice improvement for VAP, CRBSI and PU in a Malaysian intensive care unit (ICU). A mixed method study approach was undertaken in a 16-bed ICU in regional Malaysia using an environmental scan, key informant interviews, staff surveys, and patient audit to elucidate factors contributing to planning for clinical practice improvement. Measurements of sustainability of practice and regard for the practice environment were assessed using validated measures. An environmental scan demonstrated high patient occupancy and case load. Nineteen percent of ICU patients developed complications according to validated measures. Survey results indicated that the majority of nurses had a good knowledge of strategies to prevent ICU complications and a positive attitude toward change processes. Engaging executive leadership was identified as crucial in priming the clinical site for practice change. Providing nurses with tools to monitor their clinical practice and empowering them to change practices are important in improving clinical outcomes.

Size and power properties of structural break unit root tests

In this article, we compare the small sample size and power properties of a newly developed endogenous structural break unit root test of Narayan and Popp (NP, 2010) with the existing two break unit root tests, namely the Lumsdaine and Papell (LP, 1997) and the Lee and Strazicich (LS, 2003) tests. In contrast to the widely used LP and LS tests, the NP test chooses the break date by maximizing the significance of the break dummy coefficient. Using Monte Carlo simulations, we show that the NP test has better size and high power, and identifies the structural breaks accurately. Power and size comparisons of the NP test with the LP and LS tests reveal that the NP test is significantly superior.

A computationally convenient unit root test with covariates, conditional heteroskedasticity and efficient detrending

When testing for a unit root in a time series, in spite of the well-known power problem of univariate tests, it is quite common to use only the information regarding the autoregressive behaviour contained in that series. In a series of influential papers, Elliott et al. (Efficient tests for an autoregressive unit root, Econometrica 64, 813–836, 1996), Hansen (Rethinking the univariate approach to unit root testing: using covariates to increase power, Econometric Theory 11, 1148–1171, 1995a) and Seo (Distribution theory for unit root tests with conditional heteroskedasticity, Journal of Econometrics 91, 113–144, 1999) showed that this practice can be rather costly and that the inclusion of the extraneous information contained in the near-integratedness of many economic variables, their heteroskedasticity and their correlation with other covariates can lead to substantial power gains. In this article, we show how these information sets can be combined into a single unit root test.