A Factor Analytic Examination of the Underlying Mechanisms of Delay Discounting

People tend to prefer smaller-but-sooner over later-but-larger rewards, indicating the subjective value of a reward is discounted as a function of time. This phenomenon is referred to as delay discounting and represents a facet of impulsivity that is associated with reward processing. Despite the empirical literature surrounding delay discounting, the underlying mechanisms are not yet well established. The current study investigated whether delay discounting belongs more to one grouping – personality traits or cognitive functioning – than the other. Additionally, neuroimaging metrics (i.e., cortical thickness) was also examined, as it has the potential to mediate these pathways to delay discounting. Data from the Human Connectome Project was used for the current study and included behavioral and neuroimaging data on 1,051 healthy young adults. Exploratory and confirmatory factor analysis (EFA and CFA, respectively) were used to investigate proposed relationships between personality and cognitive variables and delay discounting and examine the extent that neuroimaging variables mediate the relationship. Results from the exploratory factor analysis revealed support for two separate latent constructs of cognition and personality. A progression of CFA models in structural equation modeling demonstrated evidence for the relationship between cognition and delay discounting, while personality appeared to have little explanatory power in understanding delay discounting. Results from the analysis examining cortical thickness in a selected brain region of interest did not provide evidence for a mediative relationship between cognition and delay discounting. This study helps to clarify and explain the construct of delay discounting and highlights the importance of cognition in reward-based decision-making

Why the Pirate Flag is the Only One Worth Flying Direct-action and the Enforcement of International Marine Wildlife Conservation Laws

The subject of international law is fraught with debate over its legitimacy and efficacy. If laws without enforcement are merely good advice, then how can the environment be meaningfully protected by international legal institutions? This thesis will examine the role that non-governmental organisations can play in enforcing international environmental laws. Specifically, the history and efficacy of international marine wildlife conservation laws, and the role of the Sea Shepherd Conservation Society in enforcing them, will be explored. In order to do so, this thesis discusses the evolution of international conservation law, through which the failures on the part of nation-states and legal institutions to comply with and enforce them will be explored. Exploring the gap between law and enforcement provides a basis for the discussion of the Sea Shepherd Conservation Society’s efficacy as a marine conservation organisation, and legitimacy as an actor in international law. The Sea Shepherd Conservation Society upholds important international marine wildlife conservation laws using both non-violent direct-action tactics, and recently, direct-intervention approaches in cooperation with governments. The organisation undertakes such actions in order to fill gaps in enforcement where nation-states lack the means, political will, or jurisdiction to institutionalise conservation. By examining three such instances where the group has effectively enforced international conservation laws, it is shown that while the goal of marine wildlife conservation is not being met by state actors, it can be by the Sea Shepherd Conservation Society. Because nation-states have not proved themselves to be viable environmental actors, there is a necessary place for non-governmental organisations like the Sea Shepherd Conservation Society in the international legal realm. This discussion thereby serves to demonstrate that the actions of the Sea Shepherd Conservation Society ensure the protection of marine wildlife, and in doing so, strengthen and confer legitimacy to international law

How reliable is morphological species delimitation in kelp? : a study of two closely related South African Ecklonia species

Includes bibliographical references.Ecklonia maxima and Ecklonia radiata are both kelp bed forming macroalgae along the South African coast, and the latter is also found in considerable abundance in Australia and New Zealand. Genetically they exist as two distinct species and can usually be differentiated morphologically, especially when occurring as geographically separate entities. However, they do appear to intergrade when growing together, where plants of apparent intermediate and indeterminate morphology have been observed. This study tested the reliability of morphology in separating these two Ecklonia species across their intraspecific range of morphological variation, from locations where the species co-occur, as well as where they appear in isolation in South Africa (both species) and Australia (E. radiata only). No individual characters reliably separated between species, yet overall size distinctions as well as the morphometric separation of hollow and solid-stiped sporophytes provide good evidence for morphological differentiation of E. radiata and E. maxima. While E. radiata clusters morphometrically, a distinction between Australian and South Africa specimens is observed. In localities where the two species are reported to co-exist morphological distinction is less clear, particularly in deep water at Buffels Bay. The blade morphology of these deep water sporophytes is distinct from both E. radiata and E. maxima across all locations, while overall size distinctions contribute most prominently to the morphological separation of E. radiata and E. maxima at De Hoop. Environmental data in combination with more detailed genetic analyses, especially those aimed at hybrid identification, are necessary to resolve the nature of these subtidal plants as well as to investigate the relationship between genetic differentiation and overlapping morphology in plants at De Hoop

How to generate statistics and influence policy using participatory methods in research : reflections on work in Malawi, 1999-2002

In Malawi in 1999–2002 we conducted research studies using participatory methods to generate population estimates; estimates of the proportion of people in a population with certain characteristics (e.g. the very food insecure); and estimates of the proportion of people in a population that should be targeted by an intervention. We claim that the statistics generated in these studies are at least as reliable as statistics obtained from traditional methods such as surveys. A key requirement is to produce results from a representative sample, which can be generalised in order to reach conclusions for the population of interest. This implies working in a larger number of sites than is common for most studies that use participatory methods. However, we argue that the Malawi experience shows that it is possible to organise such studies at a reasonable cost. Other key requirements are for the study design to incorporate statistical principles; and for PRA tools to be adapted to meet the demands of standardisation and comparability of data produced across sites. We argue that this can be done without undermining participatory approaches, behaviours and methods. If research studies using participatory methods follow this approach, the data generated will be suitable for standard statistical analysis. The statistics produced by such studies should be capable of informing policy at national level. However, there are some concerns about empowerment and ethical issues, which present challenges for the future

Developing a Massive Open Online Course (MOOC) at a College of Education: Narrative of Disruptive Innovation?

A case study involving the establishment of a connectivist massive open online course (cMOOC) at a college of education is presented. cMOOCs are seen to represent an approach to learning that should be of interest to educators preparing their learners (the teachers of tomorrow) for life and work in a knowledge society. In other words, the cMOOC becomes an example of innovation and change, and an object of inquiry into organizational change and leadership. The chapter examines the case of establishing a cMOOC at the college using a methodology for analyzing organizational transformation triggered by the adoption of computing technologies. The organizational voices arising from this case study echoed a disruptive nature of the cMOOC idea as something that might break the boundaries of the institution while the locus of control moves from the official representative inside the institution to the students, websites and people outside. Although the analysis is based on data gathered from stakeholders in a specific higher education institution, it has implications for understanding organizational transformations in light of technological innovation that reach far beyond the specific college of education

A propos de la désirabilité et de la faisabilité entrepreneuriales perçues pour les jeunes femmes libanaises: une enquête exploratoire.

Ce texte qui valorise le mémoire de Master de Sara SAWMA (Co-Auteur) dans le cadre des MBA de l'USEK (Liban) a été présenté au colloque du LAAS.Initiant un programme de recherches visant à étudier l'intention entrepreneuriale des femmes sur l'ensemble du Moyen-Orient tout en tenant compte du facteur religieux, ce travail préliminaire s'intéresse au contexte libanais et s'appuie sur une enquête par questionnaire conduite auprès de 140 étudiants au Liban. Les résultats recueillis reflètent la persistance de préjugés socioculturels susceptibles de freiner l'entrepreneuriat féminin ainsi que l'importance de discriminations perçues. Pour autant, les conclusions de cette étude sont plus nuancées que ne le laisse présager le sens commun et traduisent sans doute une évolution progressive des mentalités

My Experience as a Jew at Passover

My Experienc

Exploring the Physics behind Dynamic Fragmentation through Parallel Simulations

The physical mechanisms underlying the dynamic fragmentation of heterogeneous brittle materials are explored through numerical simulations. The use of computational facilities, rather than experimental or fundamental sciences, ensures the accurate tracking of rapidly evolving fields (such as stress field, energies and damage). The numerical framework is based on Galerkin approximations coupled to the Cohesive Zone model, which addresses the failure response. Depending on the number of degrees of freedom, serial or parallel simulations are performed. The finite element method with dynamic insertion of cohesive elements constitutes the basis of the serial calculations. However, it is replaced by the scalable discontinuous Galerkin formulation for parallel computing. Both frameworks recover accurately the physical mechanisms behind dynamic fragmentation. The thesis is organized to handle gradually increasing complexity. First, the fragmentation of a quasi one-dimensional expanding ring, constituted of a heterogeneous material, is simulated. It involves two major mechanisms: crack initiation and crack interaction. Fragment sizes are highly dependent upon strain rate, material properties, and microstructural heterogeneity. Scaling laws of the average fragment size, as well as of the distribution of fragment masses, are proposed and lead to predictable laws. Then, crack propagation mechanisms are investigated through parallel simulations of the quasi three-dimensional breakage of a thin plate. By analyzing the energetic response, two regimes are defined: the strength controlled and the toughness controlled. At low strain rates, defects play a key role and govern energy levels. They correspond to the strength controlled regime and induce disordered responses. At high strain rates, fragmentation is more organized, fragment masses follow Weibull distributions, and crack interactions become secondary. This is the toughness controlled regime, governed by energetic arguments. The transition between the two regimes is derived as a function of material parameters. Finally, the transition between two- and three-dimensional fragmentation is analyzed. Massively parallel simulations of the fragmentation of a hollow sphere with variable thickness are conducted. The effect of dimensionality upon fragment shape and fragment mass distributions is analyzed. Interestingly, although these three tests involve distinct mechanisms due to the specimen geometry, they share common behaviors. Quasi-static loadings lead to highly dynamic fragmentation processes, involving extensive stress wave interactions. Defect distributions play a key role. By contrast, dynamic loadings are associated to smoother and more deterministic responses. They are primarily controlled by energy arguments. As suggested by Grady's energy balance theory, this results in a predictable dependence of the average fragment size and strain rate, characterized by a power law of exponent -2/3. However, we recover more fragments than Grady because of our ability to reproduce explicitly and accurately time-dependent mechanisms (dynamics of stress waves and energy transfers). Therefore, the interpretation of these numerical results sheds light on the complexity of the physics underlying fragmentation. The dynamics of stress waves, energetic arguments, the loading conditions, the dimensionality of the geometry, and the material itself (bulk and defects) must be all evoked to draw a global picture of the phenomenon. Reproducing such processes requires a high level of accuracy that novel parallel numerical frameworks are able to provide