Contrast sensitivity changes due to glaucoma and normal aging: low-spatial-frequency losses in both magnocellular and parvocellular pathways

PURPOSE: To explore the effects of glaucoma and aging on low-spatial-frequency contrast sensitivity by using tests designed to assess performance of either the magnocellular (M) or parvocellular (P) visual pathways. METHODS: Contrast sensitivity was measured for spatial frequencies of 0.25 to 2 cyc/deg by using a published steady- and pulsed-pedestal approach. Sixteen patients with glaucoma and 16 approximately age-matched control subjects participated. Patients with glaucoma were tested foveally and at two midperipheral locations: (1) an area of early visual field loss, and (2) an area of normal visual field. Control subjects were assessed in matched locations. An additional group of 12 younger control subjects (aged 20-35 years) were also tested. RESULTS: Older control subjects demonstrated reduced sensitivity relative to the younger group for the steady (presumed M)- and pulsed (presumed P)-pedestal conditions. Sensitivity was reduced foveally and in the midperiphery across the spatial frequency range. In the area of early visual field loss, the glaucoma group demonstrated further sensitivity reduction relative to older control subjects across the spatial frequency range for both the steady- and pulsed-pedestal tasks. Sensitivity was also reduced in the midperipheral location of "normal" visual field for the pulsed condition. CONCLUSIONS: Normal aging results in a reduction of contrast sensitivity for the low-spatial-frequency-sensitive components of both the M and P pathways. Glaucoma results in a further reduction of sensitivity that is not selective for M or P function. The low-spatial-frequency-sensitive channels of both pathways, which are presumably mediated by cells with larger receptive fields, are approximately equivalently impaired in early glaucoma.

An activity theory framework for industrial design

Ethnography has gained wide acceptance in the industrial design profession and curriculum as a means of understanding the user. However, there is considerable confusion about the particularities of its practice accompanied by the absence of an interoperable vocabulary. The consequent interdisciplinary effort is a power play between disciplines whereby the methodological view of ethnography marginalises its theoretical and analytical components. In doing so, it restricts the potential of ethnography suggesting the need for alternative methods of informing the design process. This article suggests that activity theory, with an emphasis on human activity as the fundamental unit of study, is an appropriate methodology for the generation of user requirements. The process is illustrated through the adaptation of an ethnographic case study, for the design of classroom furniture in India.

Achieving better stewardship of major infrastructure assets through configuration of governance arrangements utilising Stewardship Theory

Major infrastructure assets are often governed by a mix of public and private organizations, each fulfilling a specific and separate role i.e. policy, ownership, operation or maintenance. This mix of entities is a legacy of Public Choice Theory influenced NPM reforms of the late 20th century. The privatization of the public sector has resulted in agency theory based ‘self-interest’ relationships and governance arrangements for major infrastructure assets which emphasize economic efficiency but which do not do not advance non-economic public values and the collective Public Interest. The community is now requiring that governments fulfill their stewardship role of also satisfying non-economic public values such as sustainability and intergenerational responsibility. In the 21st century governance arrangements which minimize individual self-interest alone and look to also pursue the interests of other stakeholders have emerged. Relational contracts, Public-Private Partnerships (PPP’s) and hybrid mixes of organizations from the state, market and network modes (Keast et al 2006) provide options for governance which better meet the interests of contractors, government and the community there is emerging a body of research which extends the consideration of the immediate governance configuration to the metagovernance environment constituted by hierarchy, regulation, industry standards, trust, culture and values. Stewardship theory has reemerged as a valuable aid in the understanding of the features of governance configurations which establish relationships between principal and agent which maximize the agent acting in the interests of the principal, even to the detriment of the agent. This body of literature suggests that an improved stewardship outcome from infrastructure governance configurations can be achieved by the application of the emerging options as to the immediate governance configuration, and the surrounding metagovernance environment. Stewardship theory provides a framework for the design of the relationships within that total governance environment, focusing on the achievement of a better, complete stewardship outcome. This paper explores the directions future research might take in seeking to improve the understanding of the design of the governance of major, critical infrastructure assets.

Educating the Other: Standpoint and Theory on the 'Internationalisation' of Higher Education

How adequate are current theoretical standpoints, tools and categories for explaining the flows of international students to Anglo/American/European universities? This essay takes a different analytic tact and historical standpoint to the study of them and us, insiders and outsiders (cf. Foley, Levinson & Hurtig, 2001), in the internationalisation of education.

Varieties of Asian capitalism : toward an institutional theory of Asian enterprise

In this paper we respond to calls for an institution-based perspective on strategy. With its emphasis upon mimetic, coercive, and normative isomorphism, institutional theory has earned a deterministic reputation and seems an unlikely foundation on which to construct a theory of strategy. However, a second movement in institutional theory is emerging that gives greater emphasis to creativity and agency. We develop this approach by highlighting co-evolutionary processes that are shaping the varieties of capitalism (VoC) in Asia. To do so, we examine the extent to which the VoC model can be fruitfully applied in the Asian context. In the spirit of the second movement of institutional theory, we describe three processes in which firm strategy collectively and intentionally feeds back to shape institutions: (1) filling institutional voids, (2) retarding institutional innovation, and (3) deploying institutional escape. We outline the key contributions contained in the articles of this Special Issue and discuss a research agenda generated by the VoC perspective.

New insights into rebound effects : theory and empirical evidence

The main objective of the thesis is to seek insights into the theory, and provide empirical evidence of rebound effects. Rebound effects reduce the environmental benefits of environmental policies and household behaviour changes. In particular, win-win demand side measures, in the form of energy efficiency and household consumption pattern changes, are seen as ways for households and businesses to save money and the environment. However, these savings have environmental impacts when spent, which are known as rebound effects. This is an area that has been widely neglected by policy makers. This work extends the rebound effect literature in three important ways, (1) it incorporates the potential for variation of rebound effects with household income level, (2) it enables the isolation of direct and indirect effects for cases of energy efficient technology adoption, and examines the relationship between these two component effects, and (3) it expands the scope of rebound effect analysis to include government taxes and subsidies. MACROBUTTON HTMLDirect Using a case study approach it is found that the rebound effect from household consumption pattern changes targeted at electricity is between 5 and 10%. For consumption pattern changes with reduced vehicle fuel use, the rebound effect is in the order of 20 to 30%. Higher income households in general are found to have a lower total rebound effect; however the indirect effect becomes relatively more significant at higher household income levels. In the win-lose case of domestic photovoltaic electricity generation, it is demonstrated that negative rebound effects can occur, which can potentially amplify the environmental benefits of this action. The rebound effect from a carbon tax, which occurs due to the re-spending of raised revenues, was found to be in the range of 11-32%. Taxes and transfers between households of different income levels also have environmental implications. For example, a more progressive tax structure, with increased low income welfare payments is likely to increase greenhouse gas emissions. Subsidies aimed at encouraging environmentally friendly consumption habits are also subject to rebound effects, as they constitute a substitution of government expenditure for household expenditure. For policy makers, these findings point to the need to incorporate rebound effects in the environmental policy evaluation process.’

Organic and acquisitive employment growth : re-examining,testing and extending Penrose's Growth Theory.

Edith Penrose’s theory of firm growth postulates that a firm’s current growth rate will be influenced by the adjustment costs of, and changes to a firm’s productive opportunity set arising from, previous growth. Although she explicitly considered the impact of previous organic growth on current organic growth, she was largely silent about the impact of previous acquisitive growth. In this paper we extend Penrose’s work to examine that the relative impact of organic and acquisitive growth on the adjustment costs and productive opportunity set of the firm. Employing a panel of commercially active enterprises in Sweden over a 10 year period our results suggest the following. First, previous organic growth acts as a constraint on current organic growth. Second, previous acquisitive growth has a positive effect on current organic growth. We conclude that organic growth and acquisitive growth constitute two distinct strategic options facing the firm, which have a differential impact on the future organic growth of the firm.

Sensitivity of proximal femoral stiffness and areal bone mineral density to changes in bone geometry and density

Areal bone mineral density (aBMD) is the most common surrogate measurement for assessing the bone strength of the proximal femur associated with osteoporosis. Additional factors, however, contribute to the overall strength of the proximal femur, primarily the anatomical geometry. Finite element analysis (FEA) is an effective and widely used computerbased simulation technique for modeling mechanical loading of various engineering structures, providing predictions of displacement and induced stress distribution due to the applied load. FEA is therefore inherently dependent upon both density and anatomical geometry. FEA may be performed on both three-dimensional and two-dimensional models of the proximal femur derived from radiographic images, from which the mechanical stiffness may be redicted. It is examined whether the outcome measures of two-dimensional FEA, two-dimensional, finite element analysis of X-ray images (FEXI), and three-dimensional FEA computed stiffness of the proximal femur were more sensitive than aBMD to changes in trabecular bone density and femur geometry. It is assumed that if an outcome measure follows known trends with changes in density and geometric parameters, then an increased sensitivity will be indicative of an improved prediction of bone strength. All three outcome measures increased non-linearly with trabecular bone density, increased linearly with cortical shell thickness and neck width, decreased linearly with neck length, and were relatively insensitive to neck-shaft angle. For femoral head radius, aBMD was relatively insensitive, with two-dimensional FEXI and threedimensional FEA demonstrating a non-linear increase and decrease in sensitivity, respectively. For neck anteversion, aBMD decreased non-linearly, whereas both two-dimensional FEXI and three dimensional FEA demonstrated a parabolic-type relationship, with maximum stiffness achieved at an angle of approximately 15o. Multi-parameter analysis showed that all three outcome measures demonstrated their highest sensitivity to a change in cortical thickness. When changes in all input parameters were considered simultaneously, three and twodimensional FEA had statistically equal sensitivities (0.41±0.20 and 0.42±0.16 respectively, p = ns) that were significantly higher than the sensitivity of aBMD (0.24±0.07; p = 0.014 and 0.002 for three-dimensional and two-dimensional FEA respectively). This simulation study suggests that since mechanical integrity and FEA are inherently dependent upon anatomical geometry, FEXI stiffness, being derived from conventional two-dimensional radiographic images, may provide an improvement in the prediction of bone strength of the proximal femur than currently provided by aBMD.

Tests of the elaborated intrusion theory of craving and desire : features of alcohol craving during treatment for an alcohol disorder

Objectives. We tested predictions from the elaborated intrusion (EI) theory of desire, which distinguishes intrusive thoughts and elaborations, and emphasizes the importance of imagery. Secondarily, we undertook preliminary evaluations of the Alcohol Craving Experience (ACE) questionnaire, a new measure based on EI Theory. Methods. Participants (N ¼ 232) were in correspondence-based treatment trials for alcohol abuse or dependence. The study used retrospective reports obtained early in treatment using the ACE, and daily self-monitoring of urges, craving, mood and alcohol consumption. Results. The ACE displayed high internal consistency and test – retest reliability and sound relationships with self-monitored craving, and was related to Baseline alcohol dependence, but not to consumption. Imagery during craving was experienced by 81%,with 2.3 senses involved on average. More frequent imagery was associated with longer episode durations and stronger craving. Transient intrusive thoughts were reported by 87% of respondents, and were more common if they frequently attempted to stop alcohol cognitions. Associations between average daily craving and weekly consumption were seen. Depression and negative mood were associated with more frequent, stronger and longer lasting desires for alcohol. Conclusions. Results supported the distinction of automatic and controlled processes in craving, together with the importance of craving imagery. They were also consistent with prediction of consumption from cross-situational averages of craving, and with positive associations between craving and negative mood. However, this study’s retrospective reporting and correlational design require that its results be interpreted cautiously. Research using ecological momentary measures and laboratory manipulations is needed before confident inferences about causality can be made.

Theory and its role in mathematics education

The increased recognition of the theory in mathematics education is evident in numerous handbooks, journal articles, and other publications. For example, Silver and Herbst (2007) examined ―Theory in Mathematics Education Scholarship‖ in the Second Handbook of Research on Mathematics Teaching and Learning (Lester, 2007) while Cobb (2007) addressed ―Putting Philosophy to Work: Coping with Multiple Theoretical Perspectives‖ in the same handbook. And a central component of both the first and second editions of the Handbook of International Research in Mathematics Education (English, 2002; 2008) was ―advances in theory development.‖ Needless to say, the comprehensive second edition of the Handbook of Educational Psychology (Alexander & Winne, 2006) abounds with analyses of theoretical developments across a variety of disciplines and contexts. Numerous definitions of ―theory‖ appear in the literature (e.g., see Silver & Herbst, in Lester, 2007). It is not our intention to provide a ―one-size-fits-all‖ definition of theory per se as applied to our discipline; rather we consider multiple perspectives on theory and its many roles in improving the teaching and learning of mathematics in varied contexts.

Imaginary relish and exquisite torture : the elaborated intrusion theory of desire

The authors argue that human desire involves conscious cognition that has strong affective connotation and is potentially involved in the determination of appetitive behavior rather than being epiphenomenal to it. Intrusive thoughts about appetitive targets are triggered automatically by external or physiological cues and by cognitive associates. When intrusions elicit significant pleasure or relief, cognitive elaboration usually ensues. Elaboration competes with concurrent cognitive tasks through retrieval of target related information and its retention in working memory. Sensory images are especially important products of intrusion and elaboration because they simulate the sensory and emotional qualities of target acquisition. Desire images are momentarily rewarding but amplify awareness of somatic and emotional deficits. Effects of desires on behavior are moderated by competing incentives, target availability, and skills. The theory provides a coherent account of existing data and suggests new directions for research and treatment.