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.

A modified LLC panel unit root test of the PPP hypothesis

In a recent study, Westerlund (Empir Econ 37:517–531, 2009) shows that the performance of the popular LLC (Levin et al., J Econ 108:1–24, 2002) panel unit root test depends critically on the choice of lag truncation used when correcting for serial correlation, and that it is only when this parameter is set as a function of time that the power raises above size. The purpose of the current paper is to propose a modified test that does not suffer from this drawback. The new test is not only simpler to compute but also superior in terms of small-sample performance, which is illustrated using an example purchasing power parity for less developed countries.

Testing for unit roots in panel time-series models with multiple level breaks

This paper proposes two new unit root tests that are appropriate in the presence of an unknown number of structural breaks in the level of the data. One is based on a single time series and the other is based on a panel of multiple series. For the estimation of the number of breaks and their locations, a simple procedure based on outlier detection is proposed. The limiting distributions of the tests are derived and evaluated in small samples using simulation experiments. The implementation of the tests is illustrated using as an example purchasing power parity.

Modelling attribute dependencies in single unit game combat settings

The relative strengths of individual units, described as attributes, determine the outcome during unit conflicts involving units in the armies of opponents in large strategy games. We describe a process for developing predictive models of the outcome for such conflicts where combat involves single unit adversaries where each unit is defined in terms of 4 fundamental attributes. These attributes: range, speed, health and damage are common to unit descriptions in many successful real-time strategy games. Our analysis process identifies three phases of game play with invariant properties that hold throughout each phase. We demonstrate the utility of this analysis by creating a model that predicts game outcomes. Predictions are validated against the game simulation. The game outcomes are explicitly related to the attributes of the two units involved, highlighting the significance and role of each attribute.

Examining adverse events after intensive care unit discharge : outcomes from a pilot questionnaire

Adverse events are common in acute clinical settings but little is known about these events occurring after Intensive Care discharge. This study aimed to develop a reliable and valid tool for exploring clinicians’ opinions of factors associated with post-Intensive Care adverse events. A convenience sample of Australian Intensive Care Liaison Nurses was invited to complete and appraise a questionnaire using structured guidelines. Content validity and internal consistency were assessed.

Twelve Intensive Care Liaison Nurses completed the questionnaire. Cronbach?s alpha coefficient showed high internal consistency for the questionnaire; all 24 items on the questionnaire had coefficients greater than 0.852. The content validity index of the questionnaire overall was 0.76.

The post-Intensive Care adverse events questionnaire demonstrated reliability and validity. It is a tool that can be used to explore clinicians? opinions of factors associated with these events. The tool is important as it facilitates further insight into the causes of post-Intensive Care adverse events.

Patient comfort in the intensive care unit : a multicentre, binational point prevalence study of analgesia, sedation and delirium management

Objective: To measure the prevalence of assessment and management practices for analgesia, sedation and delirium in patients in Australian and New Zealand intensive care units.
Materials and Methods: We developed survey items from a modified Delphi panel and included them in a binational, point prevalence study. We used a standard case report form to capture retrospective patient data on management of analgesia, sedation and delirium at the end of a 4-hour period on the study day. Other data were collected during independent assessment of patient status and medication requirements.
Results: Data were collected on 569 patients in 41 ICUs. Pain assessment was documented in the 4 hours before study observation in 46% of patients. Of 319 assessable patients, 16% had moderate pain and 6% had severe pain. Routine sedation assessment using a scale was recorded in 63% of intubated and ventilated patients. When assessed, 38% were alert and calm, or drowsy and rousable, 22% were lightly to moderately sedated, 31% were deeply sedated (66% of these had a documented indication), and 9% were agitated or restless. Sedatives were titrated to a target level in 42% of patients. Routine assessment of delirium occurred in 3%, and at study assessment 9% had delirium. Wrist or arm restraints were used for 7% of patients.
Conclusions: Only two-thirds of sedated patients had their sedation levels formally assessed, half had pain assessed and very few had formal assessment of delirium. Our description of current practices, and other observational data, may help in planning further research in this area.

Innovative unit delivery : the supported cloud

Deakin University has recently moved to an academic calendar of three trimesters. This change aims to provide students with greater flexibility to plan their study around work or life commitments, create options for students to commence their degree and enable students to fast track their study. It has been found for students in the Bachelor of Construction Management that engagement and satisfaction during summer (Trimester 3) are less than when those same units are delivered during other trimesters. This research addresses the use of Supported Cloud learning to improve learning and the relationship with students. The School of Architecture and Built Environment used two units as case studies to examine different innovative unit delivery strategies that combined cloud and located learning. The research design included evaluation surveys, questionnaires, and semi-structured interviews as well as reflection by participating teachers. The findings show that students’ results are improved when the cloud based learning is supported by well-developed resources, structured delivery and availability of some face-to-face contacts. This innovation will serve as a benchmark for Cloud delivery in the School in all trimesters.

Innovative unit delivery : the supported cloud

Deakin University has recently moved to an academic calendar of three trimesters. This change aims to provide students with greater flexibility to plan their study around work or life commitments, create options for students to commence their degree and enable students to fast track their study. It has been found for students in the Bachelor of Construction Management that engagement and satisfaction during summer (Trimester 3) are less than when those same units are delivered during other trimesters. This research addresses the use of Supported Cloud learning to improve learning and the relationship with students. The School of Architecture and Built Environment used two units as case studies to examine different innovative unit delivery strategies that combined cloud and located learning. The research design included evaluation surveys, questionnaires, and semi-structured interviews as well as reflection by participating teachers. The findings show that students’ results are improved when the cloud based learning is supported by well-developed resources, structured delivery and availability of some face-to-face contacts. This innovation will serve as a benchmark for Cloud delivery in the School in all trimesters.