Influence of Working Memory on the Relationship Between Depressive Symptoms and Attention for Dysphoric Stimuli

Cognitive models suggest that depressed individuals display biased attention for depression-relevant information. One factor that contributes to our ability to attend to information is working memory. Research suggests that depressed individuals show deficits in working memory. This study experimentally examined the role of working memory on the relationship between depressive symptoms and attention for dysphoric stimuli. We tested four hypotheses: 1) increased depression would be associated with increased attention for dysphoric emotional stimuli; 2) increased depression symptoms would be associated with deficits to phonological and visuospatial working memory; 3) there would be an indirect effect of working memory on the relationship between depression symptoms and attention for dysphoric stimuli; and 4) a working memory load would moderate the relationship between depression symptoms and attention for dysphoric stimuli such that under a load condition, the relationship between depressive symptoms and attention for dysphoric stimuli would be stronger than in a no load condition. One hundred forty-seven participants completed measures of depressive symptoms, social anxiety symptoms, phonological and visuospatial working memory tasks, and two runs of an eye tracking task measuring attention bias to emotional facial expressions. During one of the eye tracking runs, participants completed The Serial Three's Task as a working memory load. Results supported our first hypothesis, that increased symptoms of depression were associated with increased attention to dysphoric stimuli, but our remaining hypotheses were unsupported. Possible explanations for our results include using non-emotionally valenced working memory tasks and The Serial Three's Task being too difficult. Nonetheless, results contribute to the growing literature examining cognitive factors and depression. Future work could examine differing levels of working memory loads, or use a working memory load that is emotionally valenced

Altruistic Duality in Evolutionary Game Theory

A game-theoretic model of social preference and enlightened self-interest is formulated. Existence of symmetry and duality in the game matrices with altruistic social preference is revealed. The model is able to quantitatively describe the dynamical evolution of altruism in prisoner's dilemma and the regime change in prey-predator dynamics.Comment: ReVTeX4, 4 papes, 2 ifigures, Typos corrected for publicatio

The management of pedagogic change in contemporary orthodox Jewish schooling

The study investigated how a pedagogic change process is managed by the divergent Haredi and Modern Orthodox streams of Orthodox Jewish schooling. Its literature study looked at the classical forms of historic Jewish pedagogy and how they have adapted to internal and external dynamics. It also examined how contemporary Orthodox schooling, specifically, is an amalgam of a variety of responses, reactions and adaptations to the radically changed landscape of modernity. The influence of the modern student profile was examined along with the affects of the inclusion of secular studies into the modern Jewish syllabus. The appropriateness of new interactive methods and technologies and the specialized teacher training they require were also explored. A qualitative study of the expert opinions of six contemporary experts was conducted and thematically analyzed along with an analysis of material from two file-sharing websites. Recommendations for educational practice and further research were proposed.Educational StudiesM. Ed. (Comparative Education

Evolutionary Markovian Strategies in 2 x 2 Spatial Games

Evolutionary spatial 2 x 2 games between heterogeneous agents are analyzed using different variants of cellular automata (CA). Agents play repeatedly against their nearest neighbors 2 x 2 games specified by a rescaled payoff matrix with two parameteres. Each agent is governed by a binary Markovian strategy (BMS) specified by 4 conditional probabilities [p_R, p_S, p_T, p_P] that take values 0 or 1. The initial configuration consists in a random assignment of "strategists" among the 2^4= 16 possible BMS. The system then evolves within strategy space according to the simple standard rule: each agent copies the strategy of the neighbor who got the highest payoff. Besides on the payoff matrix, the dominant strategy -and the degree of cooperation- depend on i) the type of the neighborhood (von Neumann or Moore); ii) the way the cooperation state is actualized (deterministically or stochastichally); and iii) the amount of noise measured by a parameter epsilon. However a robust winner strategy is [1,0,1,1].Comment: 18 pages, 8 figures (7 of these figures contain 4 encapsulapted poscript files each

Higher order topological actions

In classical mechanics, an action is defined only modulo additive terms which do not modify the equations of motion; in certain cases, these terms are topological quantities. We construct an infinite sequence of higher order topological actions and argue that they play a role in quantum mechanics, and hence can be accessed experimentally.Comment: 7 page

The resilience of embodied energy networks: a critical dimension for Sustainable Development Goals (SDGs)

Access, renewables and efficiency have been identified as targets in the field of energy under the Sustainable Development Goals (SDGs). Resilience is also a critical dimension that needs to be considered in moving towards sustainable energy. Diversification of direct energy suppliers has been the conventional recourse for achieving energy security. In consideration of the increasingly globalized nature of trade, energy and supply chain networks, however, this approach would be insufficient for addressing the resilience of energy supplies to potential environmental, economic and social shocks and disruptions. In this paper we investigate countries' energy resilience by quantifying diversity in suppliers of both direct and embodied energy and examine how selections of indirect energy supplies can affect the resilience of the entire embodied-energy trade network. We find that the geographical diversity of embodied energy imports is much greater than that of direct energy imports, and there are considerable variations across countries in the diversification of embodied energy imports. This suggests a possible strategy for countries that depend heavily on a few neighbors for their direct energy imports to diversify their supply chain globally in order to benefit from larger diversity of embodied energy supplies, thereby strengthening the energy resilience of their economies

Mechanical harvesting of leafy greens on small farms

Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (page 47).Over the last century and a half, farming practices have been revolutionized by the advent of mechanical harvesters, but there is a disparity between available agricultural technology and the technology used in the farm equipment that is affordable for operators of small farms. The harvesting practices for salad greens from small farms is just one example of this disconnect. This thesis is a historical and design study of mechanical salad green harvesters for small farms. The designs consist of a frame with power, cutting and collection systems mounted to the frame. Developing an inexpensive salad greens harvester would help small produce farms in one way, but it is only a step toward the overall transition inventors, entrepreneurs and manufacturers need to make toward equipping small farms with the technology that is already in use on large farms. Many consumers have begun deliberately purchasing from local sources. It would be advantageous for farmers and manufacturers alike if agricultural industries began deliberately addressing the demand from small farms.by Kathleen Kraines.S.B

Conditional Quantum Walk and Iterated Quantum Games

Iterated bipartite quantum games are implemented in terms of the discrete-time quantum walk on the line. Our proposal allows for conditional strategies, as two rational agents make a choice from a restricted set of two-qubit unitary operations. Several frequently used classical strategies give rise to families of corresponding quantum strategies. A quantum version of the Prisoner's Dilemma in which both players use mixed strategies is presented as a specific example. Since there are now quantum walk physical implementations at a proof-of principle stage, this connection may represent a step towards the experimental realization of quantum games.Comment: Revtex 4, 6 pages, 3 figures. Expanded version with one more figure and updated references. Abstract was rewritte

Special metrics and Triality

We investigate a new 8-dimensional Riemannian geometry defined by a generic closed and coclosed 3-form with stabiliser PSU(3), and which arises as a critical point of Hitchin's variational principle. We give a Riemannian characterisation of this structure in terms of invariant spinor-valued 1-forms, which are harmonic with respect to the twisted Dirac operator \Db on $\Delta\otimes\Lambda^1$. We establish various obstructions to the existence of topological reductions to PSU(3). For compact manifolds, we also give sufficient conditions for topological PSU(3)-structures that can be lifted to topological SU(3)-structures. We also construct the first known compact example of an integrable non-symmetric PSU(3)-structure. In the same vein, we give a new Riemannian characterisation for topological quaternionic K\"ahler structures which are defined by an $Sp(1)\cdot Sp(2)$-invariant self-dual 4-form. Again, we show that this form is closed if and only if the corresponding spinor-valued 1-form is harmonic for \Db and that these equivalent conditions produce constraints on the Ricci tensor.Comment: 41 pages. v2: typos corrected, presentation improved v3: final versio