Future long-horizon performance measurement conditional on past survival

This paper examines the measurement of long-horizon abnormal performance when stock selection is conditional on an extended period of past survival. Filtering on survival results in a sample driven towards more-established, frequently traded stocks and this has implications for the choice of benchmark used in performance measurement (especially in the presence of the well-documented size effect). A simulation study is conducted to document the properties of commonly employed performance measures conditional on past survival. The results suggest that the popular index benchmarks used in long-horizon event studies are severely biased and yield test statistics that are badly misspecified. In contrast, a matched-stock benchmark based on size and industry performs consistently well. Also, an eligible-stock index designed to mitigate the influence of the size effect proves effective.

A medial to lateral shift in premovement cortical activity in hemi-Parkinson's disease: Studies of event-related potentials and whole-scalp magneto encephalography

Cortical activity associated with voluntary movement is shifted from medial to lateral premotor areas in Parkinson's disease. This occurs bilaterally, even for unilateral movements. We have used both EEG and MEG to further investigate medial and lateral premotor activity in patients with hemi-Parkinson's disease, in whom basal ganglia impairment is most pronounced in one hemisphere. The CNV, recorded from 21 scalp positions in a Go/NoGo task, was maximal over central medial regions in control subjects. For hemi-Parkinson's disease subjects, activity was shifted more frontally, reduced in the midline and lateralised towards the side of greatest basal ganglia impairment. With 143 channel whole-scalp magneto encephalography (MEG) we are further examining asymmetries in supplementary motor/premotor cortical activity prior to self-paced voluntary movement. In preliminary results, one hemi-Parkinson's disease patient with predominantly left-side symptoms showed strong medial activity consistent with a dominant source in the left supplementary motor area (SMA). Three patients showed little medial activity, but early bilateral sources within lateral premotor cortex. Results suggest greater involvement of lateral premotor rather than the SMA prior to movement in Parkinson's disease and provide evidence for asymmetric function of the SMA in hemi- Parkinson's disease, with reduced activity on the side of greatest basal ganglia deficit.

Premovement activity of the pre-supplementary motor area and the readiness for action: Studies of time-resolved event-related functional MRI

The supplementary motor area (SMA) is thought to play in important role in the preparation and organisation of voluntary movement. It has long been known that cortical activity begins to increase up to 2 s prior to voluntary self-initiated movement. This increasing premovement activity measured in EEG is known as the Bereitschaftspotential or readiness potential. Modern functional brain imaging methods, using event-related and time-resolved functional MRI techniques, are beginning to reveal the role of the SMA, and in particular the more anterior pre-SMA, in premovement activity associated with the readiness for action. In this paper we review recent studies using event-related time-resolved fMRI methods to examine the time-course of activation changes within the SMA throughout the preparation, readiness and execution of action. These studies suggest that the preSMA plays a common role in encoding or representing actions prior to our own voluntary self-initiated movements, during motor imagery, and from the observation of others' actions. We suggest that the pre-SMA generates and encodes motor representations which are then maintained in readiness for action. (c) 2005 Elsevier B.V. All rights reserved.

The preparation and execution of self-initiated and externally-triggered movement: A study of event-related fMRI

Studies of functional brain imaging in humans and single cell recordings in monkeys have generally shown preferential involvement of the medially located supplementary motor area (SMA) in self-initiated movement and the lateral premotor cortex in externally cued movement. Studies of event-related cortical potentials recorded during movement preparation, however, generally show increased cortical activity prior to self-initiated movements but little activity at early stages prior to movements that are externally cued at unpredictable times. In this study, the spatial location and relative timing of activation for self-initiated and externally triggered movements were examined using rapid event-related functional MRI. Twelve healthy right-handed subjects were imaged while performing a brief finger sequence movement (three rapid alternating button presses: index-middle-index finger) made either in response to an unpredictably timed auditory cue (between 8 to 24 s after the previous movement) or at self-paced irregular intervals. Both movement conditions involved similar strong activation of medial motor areas including the pre-SMA, SMA proper, and rostral cingulate cortex, as well as activation within contralateral primary motor, superior parietal, and insula cortex. Activation within the basal ganglia was found for self-initiated movements only, while externally triggered movements involved additional bilateral activation of primary auditory cortex. Although the level of SMA and cingulate cortex activation did not differ significantly between movement conditions, the timing of the hemodynamic response within the pre-SMA was significantly earlier for self-initiated compared with externally triggered movements. This clearly reflects involvement of the pre-SMA in early processes associated with the preparation for voluntary movement. (C) 2002 Elsevier Science.

Event-related FMRI analysis with maximum correlation modelling

Functional magnetic resonance imaging (FMRI) analysis methods can be quite generally divided into hypothesis-driven and data-driven approaches. The former are utilised in the majority of FMRI studies, where a specific haemodynamic response is modelled utilising knowledge of event timing during the scan, and is tested against the data using a t test or a correlation analysis. These approaches often lack the flexibility to account for variability in haemodynamic response across subjects and brain regions which is of specific interest in high-temporal resolution event-related studies. Current data-driven approaches attempt to identify components of interest in the data, but currently do not utilise any physiological information for the discrimination of these components. Here we present a hypothesis-driven approach that is an extension of Friman's maximum correlation modelling method (Neurolmage 16, 454-464, 2002) specifically focused on discriminating the temporal characteristics of event-related haemodynamic activity. Test analyses, on both simulated and real event-related FMRI data, will be presented.

Mild myocardial infarction - A classification problem in epidemiologic studies

In studies assessing the trends in coronary events, such as the World Health Organization (WHO) MONICA Project (multinational MONItoring of trends and determinants of CArdiovascular disease), the main emphasis has been on coronary deaths and non-fatal definite myocardial infarctions (MI). It is, however, possible that the proportion of milder MIs may be increasing because of improvements in treatment and reductions in levels of risk factors. We used the MI register data of the WHO MONICA Project to investigate several definitions for mild non-fatal MIs that would be applicable in various settings and could be used to assess trends in milder coronary events. Of 38 populations participating in the WHO MONICA MI register study, more than half registered a sufficiently wide spectrum of events that it was possible to identify subsets of milder cases. The event rates and case fatality rates of MI are clearly dependent on the spectrum of non-fatal MIs, which are included. On clinical grounds we propose that the original MONICA category ''non-fatal possible MI'' could bt:divided into two groups: ''non fatal probable MI'' and ''prolonged chest pain.'' Non-fatal probable MIs are cases, which in addition to ''typical symptoms'' have electrocardiogram (EGG) or enzyme changes suggesting cardiac ischemia, but not severe enough to fulfil the criteria for non-fatal definite MI In more than half of the MONICA Collaborating Centers, the registration of MI covers these milder events reasonably well. Proportions of non-fatal probable MIs vary less between populations than do proportions of non fatal possible MIs. Also rates of non-fatal probable MI are somewhat more highly correlated with rates of fatal events and non-fatal definite MI. These findings support the validity of the category of non-fatal probable MI. In each center the increase in event rates and the decrease in case-fatality due to the inclusion of non-fatal probable MI was lar er for women than men. For the WHO MONICA Project and other epidemiological studies the proposed category of non-fatal probable MIs can be used for assessing trends in rates of milder MI. Copyright (C) 1997 Elsevier Science Inc.

The semantic interference effect in the picture-word paradigm: An event-related fMRI study employing overt responses

We used event-related functional magnetic resonance imaging (fMRI) to investigate neural responses associated with the semantic interference (SI) effect in the picture-word task. Independent stage models of word production assume that the locus of the SI effect is at the conceptual processing level (Levelt et al. [1999]: Behav Brain Sci 22:1-75), whereas interactive models postulate that it occurs at phonological retrieval (Starreveld and La Heij [1996]: J Exp Psychol Learn Mem Cogn 22:896-918). In both types of model resolution of the SI effect occurs as a result of competitive, spreading activation without the involvement of inhibitory links. These assumptions were tested by randomly presenting participants with trials from semantically-related and lexical control distractor conditions and acquiring image volumes coincident with the estimated peak hemodynamic response for each trial. Overt vocalization of picture names occurred in the absence of scanner noise, allowing reaction time (RT) data to be collected. Analysis of the RT data confirmed the SI effect. Regions showing differential hemodynamic responses during the SI effect included the left mid section of the middle temporal gyrus, left posterior superior temporal gyrus, left anterior cingulate cortex, and bilateral orbitomedial prefrontal cortex. Additional responses were observed in the frontal eye fields, left inferior parietal lobule, and right anterior temporal and occipital cortex. The results are interpreted as indirectly supporting interactive models that allow spreading activation between both conceptual processing and phonological retrieval levels of word production. In addition, the data confirm that selective attention/response suppression has a role in resolving the SI effect similar to the way in which Stroop interference is resolved. We conclude that neuroimaging studies can provide information about the neuroanatomical organization of the lexical system that may prove useful for constraining theoretical models of word production. (C) 2001 Wiley-Liss, Inc.

The beliefs of nurses who were involved in a whistleblowing event

Background. Nursing codes of ethics bind nurses to the role of patient advocate and compel them to take action when the rights or safety of a patient are jeopardized. Reporting misconduct is known as whistleblowing and studies indicate that there are personal and professional risks involved in blowing the whistle. Aim. The aim of this study was to explore the beliefs of nurses who wrestled with this ethical dilemma. Design. A descriptive survey design was used to examine the beliefs of nurses in Western Australia who reported misconduct (whistleblowers) and of those who did not report misconduct (nonwhistleblowers). Methods. The instrument listed statements from current ethical codes, statements from traditional views on nursing and statements of beliefs related to the participant's whistleblowing experience. Respondents were asked to rate each item on a five-point Likert format which ranged from strongly agree to strongly disagree. Data were analysed using a Pearson's correlation matrix and one-way ANOVA. To further explore the data, a factor analysis was run with varimax rotation. Results. Results indicated that whistleblowers supported the beliefs inherent in patient advocacy, while nonwhistleblowers retained a belief in the traditional role of nursing. Participants who reported misconduct (whistleblowers) supported the belief that nurses were primarily responsible to the patient and should protect a patient from incompetent or unethical people. Participants who did not report misconduct (nonwhistleblowers) supported the belief that nurses are obligated to follow a physician's order at all times and that nurses are equally responsible to the patient, the physician and the employer. Conclusion. These findings indicate that nurses may respond to ethical dilemmas based on different belief systems.

Orthographic/phonological facilitation of naming responses in the picture-word task: An event-related fMRI study using overt vocal responding

In the picture-word interference task, naming responses are facilitated when a distractor word is orthographically and phonologically related to the depicted object as compared to an unrelated word. We used event-related functional magnetic resonance imaging (fMRI) to investigate the cerebral hemodynamic responses associated with this priming effect. Serial (or independent-stage) and interactive models of word production that explicitly account for picture-word interference effects assume that the locus of the effect is at the level of retrieving phonological codes, a role attributed recently to the left posterior superior temporal cortex (Wernicke's area). This assumption was tested by randomly presenting participants with trials from orthographically related and unrelated distractor conditions and acquiring image volumes coincident with the estimated peak hemodynamic response for each trial. Overt naming responses occurred in the absence of scanner noise, allowing reaction time data to be recorded. Analysis of this data confirmed the priming effect. Analysis of the fMRI data revealed blood oxygen level-dependent signal decreases in Wernicke's area and the right anterior temporal cortex, whereas signal increases were observed in the anterior cingulate, the right orbitomedial prefrontal, somatosensory, and inferior parietal cortices, and the occipital lobe. The results are interpreted as supporting the locus for the facilitation effect as assumed by both classes of theoretical model of word production. In addition, our results raise the possibilities that, counterintuitively, picture-word interference might be increased by the presentation of orthographically related distractors, due to competition introduced by activation of phonologically related word forms, and that this competition requires inhibitory processes to be resolved. The priming effect is therefore viewed as being sufficient to offset the increased interference. We conclude that information from functional imaging studies might be useful for constraining theoretical models of word production. (C) 2002 Elsevier Science (USA).

A stress and coping approach to organisational change: Evidence from three field studies

In this paper, a stress and coping perspective is used to outline the processes that determine employee adaptation to organisational change. A theoretical framework that simultaneously considers the effects of event characteristics, situational appraisals, coping strategies, and coping resources is reviewed, Three empirical investigations of organisational change that have tested various components of the model are then presented. In the first study, there was evidence linking event characteristics, situational appraisals, coping strategies and coping resources to levels of employee adjustment in a sample of pilots employed in a newly merged airline company. In a more focused test of the model with a sample of employees experiencing a restructuring process in their Organisation it was found that the provision of change-related information enhanced levels of efficacy to deal with the change process which, in turn, predicted psychological wellbeing, client engagement, and job satisfaction. In a study of managers affected by a new remuneration scheme, there was evidence to suggest that managers who received change-specific information and opportunities to participate in the change process reported higher levels of change readiness. Managers who reported higher levels of readiness for change also reported higher levels of psychological wellbeing and job satisfaction. These studies highlight ways in which managers and change agents can help employees to cope during times of organisational change.

Event-related potential correlates of impaired visuospatial working memory in schizophrenia

Previous studies have reported that patients with schizophrenia demonstrate impaired performance during working memory (WM) tasks. The current study aimed to determine whether WM impairments in schizophrenia are accompanied by reduced slow wave (SW) activity during on-line maintenance of mnemonic information. Event-related potentials were obtained from patients with schizophrenia and well controls as they performed a visuospatial delayed response task. On 50% of trials, a distractor stimulus was introduced during the delay. Compared with controls, patients with schizophrenia produced less SW memory negativity, particularly over the right hemisphere, together with reduced frontal enhancement of SW memory negativity in response to distraction. The results indicate that patients with schizophrenia generate less maintenance phase neuronal activity during WM performance, especially under conditions of distraction.

Regional development rhrough domestic and tourist event policies: Gold Coast and Brisbane 1974-2003

Governments, as key stakeholders in the development of events, produce policies to facilitate the growth and potential of events as a platform for industry and economic development. To date, however, there has been a paucity of research undertaken to determine the appropriateness and the consequences of government policies pertaining to events. This paper studies the event policies of two Australian local government authorities, the Gold Coast City Council and Brisbane City Council, from 1974-2003, as measured by four development paradigms: Modernisation, Dependency, Economic Neoliberalism, and Alternative. The analysis revealed that these policies were predominantly underpinned by the Alternative which has a strong socio-cultural focus. Increased awareness and utilisation of the various development paradigms will assist local governments in producing future event policies to promote growth of the event industry and concomitantly, appropriate development within their region.