Dynamical density functional theory for the diffusion of injected Brownian particles

While the theory of diffusion of a single Brownian particle in confined geometries is well-established by now, we discuss here the theoretical framework necessary to generalize the theory of diffusion to dense suspensions of strongly interacting Brownian particles. Dynamical density functional theory (DDFT) for classical Brownian particles represents an ideal tool for this purpose. After outlining the basic ingredients to DDFT we show that it can be readily applied to flowing suspensions with time-dependent particle sources. Particle interactions lead to considerable layering in the mean density profiles, a feature that is absent in the trivial case of noninteracting, freely diffusing particles. If the particle injection rate varies periodically in time with a suitable frequency, a resonance in the layering of the mean particle density profile is predicted

Liquid pair correlations in four spatial dimensions: Theory versus simulation

Using liquid integral equation theory, we calculate the pair correlations of particles that interact via a smooth repulsive pair potential in d = 4 spatial dimensions. We discuss the performance of different closures for the Ornstein-Zernike equation, by comparing the results to computer simulation data. Our results are of relevance to understand crystal and glass formation in high-dimensional systems

Automatisch melken: risicofactoren voor de uiergezondheid = Automatic milking: risk factors for udder health

An epidemiological study is performed on 150 dairy farms milking with an automatic milking system to identify possible risk factors for udder healt

Challenges in the Conservation of an Over-Harvested Plant Species with High Socioeconomic Values

Overexploitation to meet commercial demands has threatened the existence of many species. In theory, one can adopt a portfolio of policies and measures from both the supply (i.e., encourage cultivation while punishing poaching) and demand (i.e., education of consumers) sides to achieve sustainable use. Here we examine the effects of governmental policies and measures towards the utilization of Aquilaria sinensis, a threatened species with high cultural and economic values. We found that, despite national protected status and a suite of government initiatives and granted projects to implement cultivation of the species, poaching persisted and even intensified. From the consumer side, current cultural education related to the species was not coupled with equally strong conservation education, which might have inadvertently reinforced the notion that wild-sourced materials are better, and facilitated a luxury goods-like market for wild products. It appeared that the current government portfolio of initiatives was highly skewed towards utilization, and therefore not effective for promoting the long term ecological persistence of the species. This finding is likely not unique to A. sinensis, nor limited to China. A more balanced portfolio of government initiatives to include stronger and more direct conservation measures towards highly exploited species is needed to achieve sustainable use of this species and related species