A Laminar Cortical Model for 3D Perception of Slanted and Curved Surfaces and of 2D Images: Developement, attention, and Bistability

A model of laminar visual cortical dynamics proposes how 3D boundary and surface representations of slated and curved 3D objects and 2D images arise. The 3D boundary representations emerge from interactions between non-classical horizontal receptive field interactions with intracorticcal and intercortical feedback circuits. Such non-classical interactions contextually disambiguate classical receptive field responses to ambiguous visual cues using cells that are sensitive to angles and disparity gradients with cortical areas V1 and V2. These cells are all variants of bipole grouping cells. Model simulations show how horizontal connections can develop selectively to angles, how slanted surfaces can activate 3D boundary representations that are sensitive to angles and disparity gradients, how 3D filling-in occurs across slanted surfaces, how a 2D Necker cube image can be represented in 3D, and how bistable Necker cuber percepts occur. The model also explains data about slant aftereffects and 3D neon color spreading. It shows how habituative transmitters that help to control developement also help to trigger bistable 3D percepts and slant aftereffects, and how attention can influence which of these percepts is perceived by propogating along some object boundaries.

The Ford administration, Angola and the perception of Post-Vietnam US credibility, 1974-1976

This thesis is a study of how the Gerald Ford administration struggled to address a perceived loss of US credibility after the collapse of Vietnam, with a focus on the role of Secretary of State Henry Kissinger in the formulation, implementation and subsequent defence of US Angolan policy. By examining the immediate post-Vietnam period, this thesis shows that Vietnam had a significant impact on Kissinger’s actions on Angola, which resulted in an ill conceived covert operation in another third world conflict. In 1974, Africa was a neglected region in Cold War US foreign policy, yet the effects of the Portuguese revolution led to a rapid decolonization of its African territories, of which Angola was to become the focus of superpower competition. After South Vietnam collapsed in April 1975, Kissinger became fixated on restoring the perceived loss of US prestige, Angola provided the first opportunity to address this. Despite objections from his advisors, Kissinger methodically engineered a covert program to assist two anti-Marxist guerrilla groups in Angola. As the crisis escalated, the media discovered the operation and the Congress decided to cease all funding. A period of heated tensions ensued, resulting in Kissinger creating a new African policy to outmanoeuvre his critics publicly, while privately castigating them to foreign leaders. This thesis argues that Kissinger’s dismissal of internal dissent and opposition from the Congress was influenced by what he perceived as bureaucrats being affected by the Vietnam syndrome, and his obsession with restoring US credibility. By looking at the private and public records – as expressed in government meetings and official reports, US newspaper and television coverage and diplomatic cables – this thesis addresses the question of how the lessons of Vietnam failed to influence Kissinger’s actions in Angola, but the lessons of Angola were heavily influential in the construction of a new US-African policy.

Practitioners’ perception of the impact of the vision of policy-makers on practice: The example of the recommendations of the Moser Commission

This paper presents the perception of practitioners of the impact of the Moser Committee recommendations and the Skills for Life agenda it generated. The paper further explores areas of convergence and divergence between practitioners’ perceptions and the underpinning values of the Moser Committee recommendations. The study utilised a range of research tools including an online questionnaire, documentary analysis and elements of discourse analysis in the collection and analysis of data. It found that there is substantial divergence between the perception of practitioners and the values underpinning policy. It concludes by suggesting that a varying perception of what constitutes sustainable education and the lack of input from practitioners into policy might be responsible for this significant divergence of opinion and also raised a question on the perceived role of practitioners in the policy‐making process.

Teachers’ perception of visual deficiencies and their impact on students

The sense of vision is people’s main source of information acquisition, hence the importance of a right diagnosis and correction, if necessary, of any faults for proper learning, especially in the early years of schooling. This article discusses the results of a survey of teachers in Andalusian schools that aimed at highlighting their knowledge of their students’ possible visual deficiencies, and its possible impact on school performance. The results indicate that such knowledge is generally limited to the type of refractive anomalies, and that they think that such anomalies are well treated in their students. Despite the importance they attach to these deficiencies on school learning, they think that other factors may have a greater role. They also consider that better training on this topic is necessary.