Eigen-Adaptation and Distributed Representation of 2-D Phase, Energy, Scale and Orientation in Spatial Vision

Distributed representations (DR) of cortical channels are pervasive in models of spatio-temporal vision. A central idea that underpins current innovations of DR stems from the extension of 1-D phase into 2-D images. Neurophysiological evidence, however, provides tenuous support for a quadrature representation in the visual cortex, since even phase visual units are associated with broader orientation tuning than odd phase visual units (J.Neurophys.,88,455–463, 2002). We demonstrate that the application of the steering theorems to a 2-D definition of phase afforded by the Riesz Transform (IEEE Trans. Sig. Proc., 49, 3136–3144), to include a Scale Transform, allows one to smoothly interpolate across 2-D phase and pass from circularly symmetric to orientation tuned visual units, and from more narrowly tuned odd symmetric units to even ones. Steering across 2-D phase and scale can be orthogonalized via a linearizing transformation. Using the tiltafter effect as an example, we argue that effects of visual adaptation can be better explained by via an orthogonal rather than channel specific representation of visual units. This is because of the ability to explicitly account for isotropic and cross-orientation adaptation effect from the orthogonal representation from which both direct and indirect tilt after-effects can be explained.

Changes in brain activation during working memory and facial recognition tasks in patients with bipolar disorder with Lamotrigine monotherapy

Verbal working memory and emotional self-regulation are impaired in Bipolar Disorder (BD). Our aim was to investigate the effect of Lamotrigine (LTG), which is effective in the clinical management of BD, on the neural circuits subserving working memory and emotional processing. Functional Magnetic Resonance Imaging data from 12 stable BD patients was used to detect LTG-induced changes as the differences in brain activity between drug-free and post-LTG monotherapy conditions during a verbal working memory (N-back sequential letter task) and an angry facial affect recognition task. For both tasks, LGT monotherapy compared to baseline was associated with increased activation mostly within the prefrontal cortex and cingulate gyrus, in regions normally engaged in verbal working memory and emotional processing. Therefore, LTG monotherapy in BD patients may enhance cortical function within neural circuits involved in memory and emotional self-regulation. © 2007 Elsevier B.V. and ECNP.

Exchange fairness and employee performance:An examination of the relationship between organizational politics and procedural justice

Data obtained from a manufacturing firm and a newspaper firm in India were used to examine the relationship between organizational politics and procedural justice in three separate studies. Study 1 constructively replicated research on the distinctiveness of the two constructs. Confirmatory factor analyses in which data from the manufacturing firm served as the development sample and data from the newspaper firm served as the validation sample demonstrated the distinctiveness of organizational politics and procedural justice. Study 2 examined the antecedents of the two constructs using data from the manufacturing firm. Structural equation modeling (SEM) results revealed formalization and participation in decision making to be positively related to procedural justice but negatively related to organizational politics. Further, authority hierarchy and spatial distance were positively related to organizational politics but unrelated to procedural justice. Study 3 examined the consequences of the two constructs in terms of task and contextual performance using data from the newspaper firm. Results of SEM analysis revealed procedural justice but not organizational politics to be related to task performance and the contextual performance dimensions of interpersonal facilitation and job dedication. © 2004 Elsevier Inc. All rights reserved.

Professionals, discretion and public sector reform in the UK:re-visiting Lipsky

Purpose – Seeks to examine how far Michael Lipsky's theory of discretion as it relates to public sector professionals as “street-level bureaucrats” is still applicable in the light of public sector reform and in particular the introduction of increased managerial control over professionals. Design/methodology/approach – The main thesis in Lipsky's work, Street-Level Bureaucracy, that street-level bureaucrats devise their own rules and procedures to deal with the dilemmas of policy implementation is linked to public sector reform over the past 25 years or so. The article differentiates between three forms of discretion, rule, task and value and assesses the extent to which these different forms of discretion have been compromised by reform. Examples are drawn principally from the literature on school teachers and social workers Findings – The findings suggest that the rule-making (hence bureaucratic) capacity of professionals at street-level is much less influential than before although it is questionable whether or not the greater accountability of professionals to management and clarity of the targets and objectives of organisations delivering public policy has liberated them from the dilemmas of street-level bureaucracy. Research limitations/implications – The work has focussed on the UK and in particular on two professions. However, it may be applied to any country which has undergone public sector reform and in particular where “new public management” processes and procedures have been implemented. There is scope for in-depth studies of a range of occupations, professional and otherwise in the UK and elsewhere. Practical implications – Policy makers and managers should consider how far the positive aspects of facilitating discretion in the workplace by reducing the need for “rule-making” to cope with dilemmas have been outweighed by increased levels of bureaucracy and the “de-skilling” of professionals. Originality/value – Lipsky's much cited and influential work is evaluated in the light of public sector reform some 25 years since it was published. The three forms of discretion identified offer the scope for their systematic application to the workplace.

Caffeine, cognition, and persuasion:evidence for caffeine increasing the systematic processing of persuasive messages

Caffeine is known to increase arousal, attention, and information processing–all factors implicated in facilitating persuasion. In a standard attitude-change paradigm, participants consumed an orange-juice drink that either contained caffeine (3.5 mg/kg body weight) or did not (placebo) prior to reading a counterattitudinal communication (anti-voluntary euthanasia). Participants then completed a thought-listing task and a number of attitude scales. The first experiment showed that those who consumed caffeine showed greater agreement with the communication (direct attitude: voluntary euthanasia) and on an issue related to, but not contained in, the communication (indirect attitude: abortion). The order in which direct and indirect attitudes were measured did not affect the results. A second experiment manipulated the quality of the arguments in the message (strong vs. weak) to determine whether systematic processing had occurred. There was evidence that systematic processing occurred in both drink conditions, but was greater for those who had consumed caffeine. In both experiments, the amount of message-congruent thinking mediated persuasion. These results show that caffeine can increase the extent to which people systematically process and arc influenced by a persuasive communication.

Should I stay or should I go? Explaining turnover intentions with organizational identification and job satisfaction

The social identity approach is a powerful theoretical framework for the understanding of individuals behaviour. The main argument is that individuals think and act on behalf of the group they belong to because this group membership adds to their social identity, which partly determines ones self-esteem. In the organizational world, social identity and self-categorization theories state that a strong organizational identification is associated with low turnover intentions. Because identification is the more general perception of shared fate between employee and organization, we propose that the relationship between identification and turnover will be mediated by job satisfaction as the more specific evaluation of ones task and working conditions. In four samples we found organizational identification feeding into job satisfaction, which in turn predicts turnover intentions.

Managing people and performance:An evidence based framework applied to health service organizations

People and their performance are key to an organization's effectiveness. This review describes an evidence-based framework of the links between some key organizational influences and staff performance, health and well-being. This preliminary framework integrates management and psychological approaches, with the aim of assisting future explanation, prediction and organizational change. Health care is taken as the focus of this review, as there are concerns internationally about health care effectiveness. The framework considers empirical evidence for links between the following organizational levels: 1. Context (organizational culture and inter-group relations; resources, including staffing; physical environment) 2. People management (HRM practices and strategies; job design, workload and teamwork; employee involvement and control over work; leadership and support) 3. Psychological consequences for employees (health and stress; satisfaction and commitment; knowledge, skills and motivation) 4. Employee behaviour (absenteeism and turnover; task and contextual performance; errors and near misses) 5. Organizational performance; patient care. This review contributes to an evidence base for policies and practices of people management and performance management. Its usefulness will depend on future empirical research, using appropriate research designs, sufficient study power and measures that are reliable and valid.

Bars and edges: what makes a feature for human vision?

There have been two main approaches to feature detection in human and computer vision - luminance-based and energy-based. Bars and edges might arise from peaks of luminance and luminance gradient respectively, or bars and edges might be found at peaks of local energy, where local phases are aligned across spatial frequency. This basic issue of definition is important because it guides more detailed models and interpretations of early vision. Which approach better describes the perceived positions of elements in a 3-element contour-alignment task? We used the class of 1-D images defined by Morrone and Burr in which the amplitude spectrum is that of a (partially blurred) square wave and Fourier components in a given image have a common phase. Observers judged whether the centre element (eg ±458 phase) was to the left or right of the flanking pair (eg 0º phase). Lateral offset of the centre element was varied to find the point of subjective alignment from the fitted psychometric function. This point shifted systematically to the left or right according to the sign of the centre phase, increasing with the degree of blur. These shifts were well predicted by the location of luminance peaks and other derivative-based features, but not by energy peaks which (by design) predicted no shift at all. These results on contour alignment agree well with earlier ones from a more explicit feature-marking task, and strongly suggest that human vision does not use local energy peaks to locate basic first-order features. [Supported by the Wellcome Trust (ref: 056093)]

Group work and cognitive style:a discursive investigation

This article investigates the relationship between work-group members’ cognitive style (as measured by Allinson and Hayes’s Cognitive Style Index), the group’s task and setting, and the way in which group members behave in the group. Behavior of a homogeneous analytic, a homogeneous intuitive, and a heterogeneous group was observed in a mechanistic setting and analyzed using discourse analysis. This study is discussed in light of a previous study in which homogeneous analytic and homogeneous intuitive groups worked in an organic setting. These two studies use different methodologies (quantitative approach versus qualitativediscursive). The benefits of methodological eclecticism are discussed.

Parent-child interaction and road behaviour:An exploratory study

The relationship between parent-child interaction and child pedestrian behaviour was investigated by comparing parent-child communication to road-crossing behaviour. Forty-four children and their parents were observed carrying out a communication task (the Map Task), and were covertly filmed crossing roads around a university campus. The Map Task provided measures of task focus and sensitivity to another's current knowledge, which we predicted would be reflected in road-crossing behaviour. We modelled indices of road behaviour with factor scores derived from a principal-component analysis of communication features, and background variables including the age, sex and traffic experience of the child, and parental education. A number of variables were significantly related to road crossing, including the age and sex of the child, the length of the conversation, and specific conversational features such as the checking and clarification of uncertain information by both parent and child. The theoretical and practical implications of the findings are discussed.

Contextual modulation involves suppression and facilitation from the center and the surround

In psychophysics, cross-orientation suppression (XOS) and cross-orientation facilitation (XOF) have been measured by investigating mask configuration on the detection threshold of a centrally placed patch of sine-wave grating. Much of the evidence for XOS and XOF comes from studies using low and high spatial frequencies, respectively, where the interactions are thought to arise from within (XOS) and outside (XOF) the footprint of the classical receptive field. We address the relation between these processes here by measuring the effects of various sizes of superimposed and annular cross-oriented masks on detection thresholds at two spatial scales (1 and 7 c/deg) and on contrast increment thresholds at 7 c/deg. A functional model of our results indicates the following (1) XOS and XOF both occur for superimposed and annular masks. (2) XOS declines with spatial frequency but XOF does not. (3) The spatial extent of the interactions does not scale with spatial frequency, meaning that surround-effects are seen primarily at high spatial frequencies. (4) There are two distinct processes involved in XOS: direct divisive suppression and modulation of self-suppression. (5) Whether XOS or XOF wins out depends upon their relative weights and mask contrast. These results prompt enquiry into the effect of spatial frequency at the single-cell level and place new constraints on image-processing models of early visual processing. © ARVO.

Creep and fatigue of a single crystal nickel base superalloy

The introduction of single crystal casting techniques has led to the development of existing nickel-base superalloys to produce materials with optimum mechanical properties in the single crystal condition. As single crystals are known to be anisotropic, a study is needed to determine the general mechanical properties of these materials, and determine the effects of crystal orientation upon them. A study has been carried out to identify the effect of orientation and temperature on the creep and fatigue properties of a development single crystal superalloy, SRR 99. Creep testing and crystal rotation experiments have been made on SRR 99 and an earlier development alloy, SRR 9. Fatigue experiments at elevated temperatures have been carried out on both notched and un-notched specimens of alloy SRR 99. To aid in this analysis, several analytical techniques have been employed including Laue x-ray orientation analysis, measurement of strain by photographic methods and microstructural examination. Crystal rotation experiments have indicated that shear of 1 precipitates by lbrace111rbrace< 112> slip systems is operative during primary creep deformation at temperatures of 750oC and 850oC. The effect of orientation variation obtained by standard casting practices was not found to be significant. Creep rupture was found to be associated with multiple crack initiation from micropores. Fatigue crack initiation in un-notched specimens was found to be related to microporosity and microstructural defects. Failure was predominantly by crystallographic crack growth on lbrace111rbrace planes. The use of linear elastic fracture mechanics to describe fatigue crack propagation in alloy SRR 99 was found to be acceptable at temperatures up to 850oC. Variation of temperature, frequency and crystal orientation was found to have only moderate effect upon crack propagation rates.

Leadership development: the role of developmental readiness, personality dispositions, and individual values

Increased awareness of the crucial role of leadership as a competitive advantage for organisations (McCall, 1998; Petrick, Scherer, Brodzinski, Quinn, & Ainina, 1999) has led to billions spent on leadership development programmes and training (Avolio & Hannah, 2008). However, research reports confusing and contradictory evidence regarding return on investment and developmental outcomes, and a lot of variance has been observed across studies (Avolio, Reichard, Hannah, Walumbwa, & Chan, 2009). The purpose of this thesis is to understand the mechanisms underlying this variability in leadership development. Of the many factors at play in the process, such as programme design and delivery, organisational support, and perceptions of relevance (Mabey, 2002; Day, Harrison, & Halpin, 2009), individual differences and characteristics stand out. One way in which individuals differ is in their Developmental Readiness (DR), a concept recently introduced in the literature that may well explain this variance and which has been proposed to accelerate development (Avolio & Hannah, 2008, 2009). Building on previous work, DR is introduced and conceptualised somewhat differently. In this study, DR is construed of self-awareness, self-regulation, and self-motivation, proposed by Day (2000) to be the backbones of leadership development. DR is suggested to moderate the developmental process. Furthermore, personality dispositions and individual values are proposed to be precursors of DR. The empirical research conducted uses a pre-test post-test quasi-experimental design. Before conducting the study, though, both a measure of Developmental Readiness and a competency profiling measure are tested in two pilot studies. Results do not find evidence of a direct effect of leadership development programmes on development, but do support an interactive effect between DR and leadership development programmes. Personality dispositions Agreeableness, Conscientiousness, and Openness to Experience and value orientations Conservation, Open, and Closed Orientation are found to significantly predict DR. Finally, the theoretical and practical implications of findings are discussed.

Innovation in teams : a qualitative and quantitative study of team behaviours

This thesis explores the processes of team innovation. It utilises two studies, an organisationally based pilot and an experimental study, to examine and identify aspects of teams' behaviours that are important for successful innovative outcome. The pilot study, based in two automotive manufacturers, involved the collection of team members' experiences through semi-structured interviews, and identified a number of factors that affected teams' innovative performance. These included: the application of ideative & dissemination processes; the importance of good team relationships, especially those of a more informal nature, in facilitating information and ideative processes; the role of external linkages in enhancing quality and radicality of innovations; and the potential attenuation of innovative ideas by time deadlines. This study revealed a number key team behaviours that may be important in successful innovation outcomes. These included; goal setting, idea generation and development, external contact, task and personal information exchange, leadership, positive feedback and resource deployment. These behaviours formed the basis of a coding system used in the second part of the research. Building on the results from the field based research, an experimental study was undertaken to examine the behavioural differences between three groups of sixteen teams undertaking innovative an task to produce an anti-drugs poster. They were randomly assigned to one of three innovation category conditions suggested by King and Anderson (1990), emergent, imported and imposed. These conditions determined the teams level of access to additional information on previously successful campaigns and the degree of freedom they had with regarding to the design of the poster. In addition, a further experimental condition was imposed on half of the teams per category which involved a formal time deadline for task completion. The teams were video taped for the duration of their innovation and their behaviours analysed and coded in five main aspects including; ideation, external focus, goal setting, interpersonal, directive and resource related activities. A panel of experts, utilising five scales developed from West and Anderson's (1996) innovation outcome measures, assessed the teams' outputs. ANOVAs and repeated measure ANOVAs were deployed to identify whether there were significant differences between the different conditions. The results indicated that there were some behavioural differences between the categories and that over the duration of the task behavioural changes were identified. The results, however, revealed a complex picture and suggested limited support for three distinctive innovation categories. There were many differences in behaviours, but rarely between more than two of the categories. A main finding was the impact that different levels of constraint had in changing teams' focus of attention. For example, emergent teams were found to use both their own team and external resources, whilst those who could import information about other successful campaigns were likely to concentrate outside the team and pay limited attention to the internal resources available within the team. In contrast, those operating under task constraints with aspects of the task imposed onto them were more likely to attend to internal team resources and pay limited attention to the external world. As indicated by the earlier field study, time deadlines did significantly change teams' behaviour, reducing ideative and information exchange behaviours. The model shows an important behavioural progression related to innovate teams. This progression involved the teams' openness initially to external sources, and then to the intra-team environment. Premature closure on the final idea before their mid-point was found to have a detrimental impact on team's innovation. Ideative behaviour per se was not significant for innovation outcome, instead the development of intra-team support and trust emerged as crucial. Analysis of variance revealed some limited differentiation between the behaviours of teams operating under the aforementioned three innovation categories. There were also distinct detrimental differences in the behaviour of those operating under a time deadline. Overall, the study identified the complex interrelationships of team behaviours and outcomes, and between teams and their context.

The antecedents and consequences of e-business adoption in Malaysian manufacturing firms

Theory suggests that firms that adopt innovation share some common characteristics, just as those who do not adopt innovation and firms adopt a particular technology because the functions provided by the chosen technology fulfils their needs. Building on these arguments, this research project investigates the antecedents and consequences of e-business adoption among manufacturing firms in Malaysia. This thesis develops from the existing literature of organisational innovation adoption, information technology and strategic marketing/management. It further adds to the existing literature by using cultural-based predictors representing organisational characteristics consisting of market orientation, innovativeness and organisational learning. The study also formalises the theoretical framework of organisational-environment-technology. This study develops a new construct called technology motivation in addition to the introduction of several e-business technology scales. The results substantiate the significance of firm technology motivation in determining firm adoption of the various e-business initiatives. In addition, business environment and market orientation are found to influence firm choice of technology motivation. Meanwhile, innovativeness and organisational learning are shown to influence the magnitude of a firm’s e-business adoption. Finally, the results show that firm adoption of e-business technology does not influence organisational performance. This investigation clarifies the rationale and importance of firm technology motivation in adopting the various e-business initiatives. It also highlights the importance of having the appropriate organisational culture in ensuring a successful technology adoption.