Particles adsorbed at various non-aqueous liquid-liquid interfaces

Particles adsorbed at liquid interfaces are commonly used to stabilise water-oil Pickering emulsions and water-air foams. The fundamental understanding of the physics of particles adsorbed at water-air and water-oil interfaces is improving significantly due to novel techniques that enable the measurement of the contact angle of individual particles at a given interface. The case of non-aqueous interfaces and emulsions is less studied in the literature. Non-aqueous liquid-liquid interfaces in which water is replaced by other polar solvents have properties similar to those of water-oil interfaces. Nanocomposites of non-aqueous immiscible polymer blends containing inorganic particles at the interface are of great interest industrially and consequently more work has been devoted to them. By contrast, the behaviour of particles adsorbed at oil-oil interfaces in which both oils are immiscible and of low dielectric constant (ε < 3) is scarcely studied. Hydrophobic particles are required to stabilise these oil-oil emulsions due to their irreversible adsorption, high interfacial activity and elastic shell behaviour

Symmetry and quaternionic integrable systems

Given a hyperkahler manifold M, the hyperkahler structure defines a triple of symplectic structures on M; with these, a triple of Hamiltonians defines a so called hyperhamiltonian dynamical system on M. These systems are integrable when can be mapped to a system of quaternionic oscillators. We discuss the symmetry of integrable hyperhamiltonian systems, i.e. quaternionic oscillators; and conversely how these symmetries characterize, at least in the Euclidean case, integrable hyperhamiltonian systems.Comment: 26 page

Innovation and jobs: evidence from manufacturing firms

This paper is aimed at structurally assessing the employment effects of the innovative activities of firms. We estimate firm level displacement and compensation effects in a model in which the stock of knowledge capital raises firm relative efficiency through process innovations and firm demand through product innovations. Displacement is estimated from the elasticity of employment with respect to innovation in the (conditional or Hicksian) demand for labour. Compensation effects are estimated from a firm-specific demand relationship. We also assess the enlargement and weakening of these effects due to firm agents’ behaviour aimed at appropriating innovation rents. We find that the potential employment compensation effect of process innovations surpasses the displacement effect, both in the short and long run (when competitors react), and that product innovation doubles the expanding impact by unit of expenditure, but also that agents’ behaviour can seriously reduce these effects. The actual elasticity of employment to knowledge capital is estimated, however, not far from unity, while “passive” productivity growth is suggested to have null or negative employment effects.

Immigrants' Assimilation Process in a Segmented Labor Market

While much of the literature on immigrants' assimilation has focused on countries with a large tradition of receiving immigrants and with flexible labor markets, very little is known on how immigrants adjust to other types of host economies. With its severe dual labor market, and an unprecedented immigration boom, Spain presents a perfect natural experiment to analyze immigrations' assimilation process. Using data from the 2000 to 2008 Spanish Labor Force Survey, we find that immigrants are more occupationally mobile than natives, and that much of this greater flexibility is explained by immigrants' assimilation process soon after arrival. However, we find little evidence of convergence, especially among women and high skilled immigrants. This suggests that instead of integrating, immigrants are occupationally segregating, implying that there is both imperfect substitutability and underutilization of immigrants' human capital.immigrants' assimilation effects, cohort effects, occupational distributions and mobility, segmented labor markets