The moments of the non-central t-distribution,

"This work was supported by the Office of Naval Reseaarch under Contract Nonr. 404(16)."

Evidence that the Bed Nucleus of the Stria Terminalis Contributes to the Modulation of Hypophysiotropic Corticotropin-Releasing Factor Cell Responses to Systemic Interleukin-1β

Systemic infection activates the hypothalamic-pituitary-adrenal (HPA) axis, and brainstem catecholamine cells have been shown to contribute to this response. However, recent work also suggests an important role for the central amygdala (CeA). Because direct connections between the CeA and the hypothalamic apex of the HPA axis are minimal, the present study investigated whether the bed nucleus of the stria terminalis (BNST) might act as a relay between them. This was done by using an animal model of acute systemic infection involving intravascular delivery of the proinflammatory cytokine interleukin-1 (IL-1, 1 g/kg). Unilateral ibotenic acid lesions encompassing the ventral BNST significantly reduced both IL-1-induced increases in Fos immunoreactivity in corticotropin-releasing factor (CRF) cells of the hypothalamic paraventricular nucleus (PVN) and corresponding increases in adrenocorticotropic hormone (ACTH) secretion. Similar lesions had no effect on CRF cell responses to physical restraint, suggesting that the effects of BNST lesions were not due to a nonspecific effect on stress responses. In further studies, we examined the functional connections between PVN, BNST, and CeA by combining retrograde tracing with mapping of IL-1-induced increases in Fos in BNST and CeA cells. In the case of the BNST, these studies showed that systemic IL-1 administration recruits ventral BNST cells that project directly to the PVN. In the case of the CeA, the results obtained were consistent with an arrangement whereby lateral CeA cells recruited by systemic IL-1 could regulate the activity of medial CeA cells projecting directly to the BNST. In conclusion, the present findings are consistent with the hypothesis that the BNST acts as a relay between the CeA and PVN, thereby contributing to CeA modulation of hypophysiotropic CRF cell responses to systemic administration of IL-1.

Hypothalamic paraventricular nucleus neurons regulate medullary catecholamine cell responses to restraint stress

Both physical and psychological stressors recruit catecholamine cells (CA) located in the ventrolateral medulla (VLM) and the nucleus of the solitary tract (NTS). In the case of physical stressors, this effect is initiated by signals that first access the central nervous system at or below the level of the medulla. For psychological stressors, however, CA cell recruitment depends on higher structures within the neuraxis. Indeed, we have recently provided evidence of a pivotal role for the medial amygdala (MeA) in this regard, although such a role must involve a relay, as MeA neurons do not project directly to the medulla. However, some of the MeA neurons that respond to psychological stress have been found to project to the hypothalamic paraventricular nucleus (PVN), a structure that provides significant input to the medulla. To determine whether the PVN might regulate medullary CA cell responses to psychological stress, animals were prepared with unilateral injections of the neurotoxin ibotenic acid into the PVN (Experiment 1), or with unilateral injections of the retrograde tracer wheat germ agglutinin-gold (WGA-Au) into the CA cell columns of the VLM or NTS (Experiment 2). Seven days later, animals were subjected to a psychological stressor (restraint; 15 minutes), and their brains were subsequently processed for Fos plus appropriate cytoplasmic markers (Experiment 1), or Fos plus WGA-Au (Experiment 2). PVN lesions significantly suppressed the stress-related induction of Fos in both VLM and NTS CA cells, whereas tracer deposits in the VLM or NTS retrogradely labeled substantial numbers of PVN cells that were also Fos-positive after stress. Considered in concert with previous results, these data suggest that the activation of medullary CA cells in response to psychological stress may involve a critical input from the PVN. (C) 2004 Wiley-Liss, Inc.

Self-determination theory: A case study of evidence-based coaching

The coach is central to the development of expertise in sport (Bloom, 1985) and is subsequently key to facilitating adaptive forms of motivation to enhance the quality of sport performance (Mallett & Hanrahan, 2004). In designing optimal training environments that are sensitive to the underlying motives of athletes, the coach requires an in-depth understanding of motivation. This paper reports on the application of self-determination theory (SDT; Deci & Ryan, 1985; Ryan & Deci, 2000) to coaching elite athletes. Specifically, the application of SDT to designing an autonomy-supportive motivational climate is outlined, which was used in preparing Australia's two men's relay teams for the 2004 Olympic Games in Athens.

A theory for execution-time derivation in real-time programs

We provide an abstract command language for real-time programs and outline how a partial correctness semantics can be used to compute execution times. The notions of a timed command, refinement of a timed command, the command traversal condition, and the worst-case and best-case execution time of a command are formally introduced and investigated with the help of an underlying weakest liberal precondition semantics. The central result is a theory for the computation of worst-case and best-case execution times from the underlying semantics based on supremum and infimum calculations. The framework is applied to the analysis of a message transmitter program and its implementation. (c) 2005 Elsevier B.V. All rights reserved.

Evidence of altered prefrontal-thalamic circuitry in schizophrenia: An optimised diffusion MRI study

MRI diffusion tensor imaging (DTI), optimized for measuring the trace of the diffusion tensor, was used to investigate microstructural changes in the brains of 12 individuals with schizophrenia compared with 12 matched control subjects. To control for the effects of anatomic variation between subject groups, all participants' diffusion images were non-linearly registered to standard anatomical space. Significant statistical differences in mean diffusivity (MD) measures between the two groups were determined on a pixel-by-pixel basis, using Gaussian random field theory. We found significantly elevated MD measures within temporal, parietal and prefrontal cortical regions in the schizophrenia group (P > 0.001), especially within the medial frontal gyrus and anterior cingulate. The dorsal medial and anterior nucleus of the thalamus, including the caudate, also exhibited significantly increased MD in the schizophrenia group (P > 0.001). This study has shown for the first time that MD measures offer an alternative strategy for investigating altered prefrontal-thalamic circuitry in schizophrenia. (c) 2006 Elsevier Inc. All rights reserved.

The network structure of a regional tourism organization: Application of he social network theory in one region of Queensland

Regional tourism organizations (RTOs) plays a central role in planning, coordinating and marketing tourism in many areas, including Queensland, Australia. RTOs rely on interaction with a network of other organizations for their efficient functioning. This paper describes an exploratory case study that develops a method for use of social network analysis techniques to analyse the inter-organizational network in one RTO region in Queensland. Results indicate that differences exist in the structure of inter-organizational links between commercial tourism organizations and planning organizations, between tourism organizations and other sectoral clusters, and between organizations at local, regional and state levels. The results highlight areas or improvement in the role and responsibilities of RTOs in Queensland.

Signal detection theory in applied tasks: The case of hazard perception in driving

Fuzzy signal detection analysis can be a useful complementary technique to traditional signal detection theory analysis methods, particularly in applied settings. For example, traffic situations are better conceived as being on a continuum from no potential for hazard to high potential, rather than either having potential or not having potential. This study examined the relative contribution of sensitivity and response bias to explaining differences in the hazard perception performance of novices and experienced drivers, and the effect of a training manipulation. Novice drivers and experienced drivers were compared (N = 64). Half the novices received training, while the experienced drivers and half the novices remained untrained. Participants completed a hazard perception test and rated potential for hazard in occluded scenes. The response latency of participants to the hazard perception test replicated previous findings of experienced/novice differences and trained/untrained differences. Fuzzy signal detection analysis of both the hazard perception task and the occluded rating task suggested that response bias may be more central to hazard perception test performance than sensitivity, with trained and experienced drivers responding faster and with a more liberal bias than untrained novices. Implications for driver training and the hazard perception test are discussed.

Asymptotic theory of time varying networks with memory and heterogeneous activation pattern

In this thesis work we develop a new generative model of social networks belonging to the family of Time Varying Networks. The importance of correctly modelling the mechanisms shaping the growth of a network and the dynamics of the edges activation and inactivation are of central importance in network science. Indeed, by means of generative models that mimic the real-world dynamics of contacts in social networks it is possible to forecast the outcome of an epidemic process, optimize the immunization campaign or optimally spread an information among individuals. This task can now be tackled taking advantage of the recent availability of large-scale, high-quality and time-resolved datasets. This wealth of digital data has allowed to deepen our understanding of the structure and properties of many real-world networks. Moreover, the empirical evidence of a temporal dimension in networks prompted the switch of paradigm from a static representation of graphs to a time varying one. In this work we exploit the Activity-Driven paradigm (a modeling tool belonging to the family of Time-Varying-Networks) to develop a general dynamical model that encodes fundamental mechanism shaping the social networks' topology and its temporal structure: social capital allocation and burstiness. The former accounts for the fact that individuals does not randomly invest their time and social interactions but they rather allocate it toward already known nodes of the network. The latter accounts for the heavy-tailed distributions of the inter-event time in social networks. We then empirically measure the properties of these two mechanisms from seven real-world datasets and develop a data-driven model, analytically solving it. We then check the results against numerical simulations and test our predictions with real-world datasets, finding a good agreement between the two. Moreover, we find and characterize a non-trivial interplay between burstiness and social capital allocation in the parameters phase space. Finally, we present a novel approach to the development of a complete generative model of Time-Varying-Networks. This model is inspired by the Kaufman's adjacent possible theory and is based on a generalized version of the Polya's urn. Remarkably, most of the complex and heterogeneous feature of real-world social networks are naturally reproduced by this dynamical model, together with many high-order topological properties (clustering coefficient, community structure etc.).

A test of basic assumptions of Affective Events Theory (AET) in call centre work

Based on data from 2091 call centre representatives working in 85 call centres in the UK, central assumptions of affective events theory (AET) are tested. AET predicts that specific features of work (e.g. autonomy) have an impact on the arousal of emotions and moods at work that, in turn, co-determine job satisfaction of employees. AET further proposes that job satisfaction is an evaluative judgement that mainly explains cognitive-based behaviour, whereas emotions and moods better predict affective-based behaviour. The results support these assumptions. A clear separation of key constructs (job satisfaction, positive and negative emotions) was possible. Moreover, correlations between several work features (e.g. supervisory support) and job satisfaction were, in part, mediated by work emotions, even when controlling for gender, age, call centre type (in-house versus outsourced centres) and call centre size. Predictions regarding consequences of satisfaction and affect were partly corroborated as continuance commitment was more strongly related to job satisfaction than to positive emotions. In addition, affective commitment and health complaints were related to both emotions and job satisfaction to the same extent. Thus, AET is a fruitful framework for explaining why and how specific management strategies used for designing work features influence important organizational attitudes and well-being of employees. © 2006 British Academy of Management.

Higher education reform in Kyrgyzstan: the politics of neoliberal agendas in theory and practice

There would seem to be no greater field for observing the effects of neo-liberal reforms in higher education than the former Soviet university, where attempts to legitimize neo-liberal philosophy over Soviet ideology plays out in everyday practices of educational reform. However, ethnographic research about higher education in post-Soviet Central Asia suggests that its “liberalization” is both an ideological myth and a complicated reality. This chapter focuses on how and why neo-liberal agendas have “travelled” to the Central Asian republic of Kyrgyzstan, what happens when educators encounter and resist them, and why these spaces of resistance are important starting points for the development of alternative visions of educational possibility in this recently “Third-worlded” society.

Functional interconnectivity between the globus pallidus and the subthalamic nucleus in the mouse brain slice

In accordance with its central role in basal ganglia circuitry, changes in the rate of action potential firing and pattern of activity in the globus pallidus (GP)-subthalamic nucleus (STN) network are apparent in movement disorders. In this study we have developed a mouse brain slice preparation that maintains the functional connectivity between the GP and STN in order to assess its role in shaping and modulating bursting activity promoted by pharmacological manipulations. Fibre-tract tracing studies indicated that a parasagittal slice cut 20 deg to the midline best preserved connectivity between the GP and the STN. IPSCs and EPSCs elicited by electrical stimulation confirmed connectivity from GP to STN in 44/59 slices and from STN to GP in 22/33 slices, respectively. In control slices, 74/76 (97%) of STN cells fired tonically at a rate of 10.3 ± 1.3 Hz. This rate and pattern of single spiking activity was unaffected by bath application of the GABAA antagonist picrotoxin (50 μM, n = 9) or the glutamate receptor antagonist (6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX) 10 μM, n = 8). Bursting activity in STN neurones could be induced pharmacologically by application of NMDA alone (20 μM, 3/18 cells, 17%) but was more robust if NMDA was applied in conjunction with apamin (20-100 nM, 34/77 cells, 44%). Once again, neither picrotoxin (50 μM, n = 5) nor CNQX (10 μM, n = 5) had any effect on the frequency or pattern of the STN neurone activity while paired STN and GP recordings of tonic and bursting activity show no evidence of coherent activity. Thus, in a mouse brain slice preparation where functional GP-STN connectivity is preserved, no regenerative synaptically mediated activity indicative of a dynamic network is evident, either in the resting state or when neuronal bursting in both the GP and STN is generated by application of NMDA/apamin. This difference from the brain in Parkinson's disease may be attributed either to insufficient preservation of cortico-striato-pallidal or cortico-subthalamic circuitry, and/or an essential requirement for adaptive changes resulting from dopamine depletion for the expression of network activity within this tissue complex. © The Physiological Society 2005.

Managing careers and managing fairness : an organisational justice theory perspective on employee evaluations of, and reactions to, organisational career management practices

This thesis presents the results of a multi-method investigation of employee perceptions of fairness in relation to their career management experiences. Organisational justice theory (OJT) was developed as a theoretical framework and data were gathered via 325 quantitative questionnaires, 20 semi-structured interviews and the analysis of a variety of company documents and materials. The results of the questionnaire survey provided strong support for the salience of employee perceptions of justice in regard to their evaluations of organisational career management (OCM) practices, with statistical support emerging for both an agent-systems and interaction model of organisational justice. The qualitative semi-structured interviews provided more detailed analysis of how fairness was experienced in practice, and confirmed the importance of the OJT constructs of fairness within this career management context. Fairness themes to emerge from this analysis included, equity, needs, voice, bias suppression, consistency, ethicality, respect and feedback drawing on many of the central tenants of distributive, procedural, interpersonal and information justice. For the career management literature there is empirical confirmation of a new theoretical framework for understanding employee evaluations of, and reactions to, OCM practices. For the justice literatures a new contextual domain is explored and confirmed, thus extending further the influence and applicability of the theory. For practitioners a new framework for developing, delivering and evaluating their own OCM policies and systems is presented.