University of Waterloo

About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.

Inelastic light scattering from correlated electrons

Abstract: Inelastic light scattering is an intensively used tool in the study of electronic properties of solids. Triggered by the discovery of high-temperature superconductivity in the cuprates and by new developments in instrumentation, light scattering in both the visible (Raman effect) and x-ray part of the electromagnetic spectrum has become a method complementary to optical (infrared) spectroscopy while providing additional and relevant information. The main purpose of the review is to position Raman scattering with regard to single-particle methods like angle-resolved photoemission spectroscopy, and other transport and thermodynamic measurements in correlated materials. Particular focus will be placed on photon polarizations and the role of symmetry to elucidate the dynamics of electrons in different regions of the Brillouin zone. This advantage over conventional transport (usually measuring averaged properties) provides new insights into anisotropic and complex many-body behavior of electrons in various systems. Recent developments in the theory of electronic Raman scattering in correlated systems and experimental results in paradigmatic materials such as the A15 superconductors, magnetic and paramagnetic insulators, compounds with competing orders, as well as the cuprates with high superconducting transition temperatures are reviewed. An overview of the manifestations of complexity in the Raman response due to the impact of correlations and developing competing orders is presented. In a variety of materials, observations which may be understood and a summary of important open questions that pave the way to a detailed understanding of correlated electron systems, are discussed.

Effect of droplet size on the rheology of emulsions

Abstract: The effect of droplet size on the rheological behavior of water-in-oil and oil-in-water emulsions was investigated using a controlled-stress rheometer. Results indicate that the droplet size has a dramatic influence on emulsion rheology. Fine emulsions (water-in-oil or oil-in-water) have much higher viscosities and storage moduli than the corresponding coarse emulsions. The shear-thinning effect is much stronger in the case of fine emulsions. When coarse droplets are replaced by fine droplets (keeping total volume fraction of the dispersed phase constant), the resulting emulsion exhibits a minimum in rheological properties (viscosity, storage and loss moduli, time constant) at a certain proportion of fine droplets. However, the minimum in viscosity occurs only at low shear stresses. At high stresses, the viscosity of the mixed emulsion increases as the proportion of fine droplets increases. The study of the aging effect on the rheological behavior shows that water-in-oil emulsions age much more rapidly than the oil-in-water emulsions.

Temporal self-regulation theory: A model for individual health behavior

Abstract: Human behavior often seems “maladaptive”, “self-defeating”, or “dysfunctional” to the observer. Upon closer examination, the rationality of human behavior largely depends on the temporal frame adopted; behaviors judged to be maladaptive in the long-run are usually driven by a strongly favorable balance of immediate costs and benefits. That is, many ‘‘maladaptive’’ behaviors are associated with substantial long-term costs and few (if any) long-term benefits; however, these same behaviors are frequently associated with many benefits and few costs for the individual at the time of action. In contrast, many avoided behaviors that seem ‘‘adaptive’’ to the outside observer, are in fact associated with substantial costs (and few benefits) at the time of action, leading to the perplexing but common state of affairs where individuals know ‘‘what is good for them’’, but do not do it. We present a new theoretical framework—Temporal Self-Regulation Theory—as a way of understanding human behavior in general, ...